How to open a mini gypsum plant

The purpose of the plant by

Equipment for production of plaster of paris intended for obtaining a binder that meets the requirements of GOST 125 -79: Gypsum binders. Technical conditions.

Heat unit at production of plaster of paris our installation is a gypsum boiler TOS165.

Depending on the ultimate compressive strength of the finished product, building gypsum of the following grades can be obtained in a gypsum boiler: G-4, G-5, G-6, G-7.

By adjusting the technological parameters of gypsum boiling, it is possible to obtain fast-hardening gypsum with index A, the beginning of setting no earlier than 2 minutes, the end no later than 15 minutes, n normally hardening B, the beginning of setting no earlier than 6 minutes, the end no later than 30 minutes.

Depending on the degree of grinding, gypsum of medium grinding can be obtained with a residue on a 0.2 mm sieve not more than 14% and fine grinding with a residue on a 0.2 mm sieve not more than 2%.

When a product is obtained with a fine grinding of less than 2%, the productivity of the equipment decreases.

Plant productivity by production of plaster of paris with an average grinding of 5-8%, the residue on a sieve 0.2 is 8 t / h.

Plant equipment for production of plaster of paris is placed on a technological shelf inside an unheated production facility.

During the construction of a new plant for the production of gypsum binder, sandwich panels are used as the enclosing structures of the production building.

The dimensions in terms of the production shelf may differ depending on the customer's specifications and the available free space. Overall dimensions in terms of 4.5 x 30 m and 9.0 x 18 m are standard.The maximum height of the equipment inside the production room is 16 m.

For the dimensions of the production shelter, as a rule, they take out the equipment for the crushing and transportation of gypsum stone and the silo cans intended for storing and languishing the finished gypsum binder.

Requirements for the starting material - gypsum stone

It is carried out using gypsum stone that meets the requirements of GOST 4013-82 grade 1 with a CaSO4 x 2H2O content of at least 95% and a grade 2 gypsum stone with a CaSO4 x 2H2O content of at least 90%. A high-quality binder in a gypsum boiler of at least G4 grade can be obtained using grade 3 gypsum stone with a CaSO4 x 2H2O content of at least 80% on solid gypsum stone.

To obtain a gypsum binder in a gypsum boiler, a gypsum stone of fraction 60 - 300 mm is used. The coarse stone is the cleanest without inclusions of foreign material. In fine crushed stone, fraction 0-60 mm, there are more inclusions of non-gypsum rock, which reduces the properties of the finished gypsum binder during gypsum cooking.

Construction gypsum production technology

Technology production of stucco with a gypsum boiler TOS165 consists of three main technological stages: 1- Crushing of gypsum stone, 2-Drying and grinding of gypsum crushed stone, 3-Cooking of stucco in a gypsum boiler TOS165.

Crushing gypsum stone

Crushing of gypsum stone of fraction 60 - 300 mm takes place in a jaw crusher.

The stone is loaded into the receiving hopper of the crusher by a front or grab loader from the storage warehouse.

For the smooth operation of gypsum production, a 15-day supply of raw materials must be kept in the warehouse.

The gypsum stone is fed into the jaw crusher by an oscillating feeder.

The size of the fraction of gypsum crushed stone after the crusher is regulated by the size of the crusher outlet slot. After the crusher, the gypsum crushed stone goes for further processing to the grinding department and drying on a belt conveyor.

The crushing department is usually located outside the enclosed production area, where gypsum is dried, milled and boiled.

The crushed material, passing through the iron separator, is fed into the axial hammer mill.

The axial hammer mill is designed for fine grinding of medium hard gypsum crushed stone with simultaneous drying. The material is fed into the mill by an oscillating feeder from a feed hopper.

Gypsum powder, ground and dried in the mill, enters the dust and gas cleaning system in a stream of hot gases. Axial hammer mills belong to the group of high-speed hammer grinding machines. The supply of crushed stone to the mill is carried out in the direction of rotation of the rotor. As a result of the blows, crushed stone is crushed into powder. The fineness of grinding of the material depends on the feed rate, the volume of the ventilating agent and on the angle of installation of the blades of the built-in separator. The flue gases of a gypsum boiler are used as a heat carrier and a ventilating agent.

The temperature of the flue gases at the entrance to the mill, depending on the selected thermal mode of gypsum firing in the boiler, can range from 250 to 500 0 С.

Gypsum powder, crushed, dried and separated to a residue of not more than 5-8% on a sieve No. 02, is carried out in a dust-air stream into a dust deposition system. As the first stage of cleaning, cyclones are used, as the second stage of cleaning, two-section bag filters TOS 3.8. To eliminate material hang-up, pneumatic impact devices are installed in the cyclone hopper. The cyclone and the bag filter are thermally insulated.

Regeneration of the bag filter is carried out by back-flushing the bags with compressed air when one of the sections is turned off by the automation system. The fabric of the "Metaaramid" type is used as the fabric for the sleeves. The fabric can withstand operating temperatures up to 230 ° C. In the event of an unplanned increase in the temperature of the waste heat carrier above the specified temperature, the dilution flap installed in front of the filter opens in automatic mode and the outside air enters the aspiration system. Compressed air is supplied with a temperature exceeding the dew point temperature by at least 5-10 0 С.

A smoke exhauster Дн is used as a traction unit.

Powder caught by cyclones and bag filters is conveyed by screw conveyors to a heat-insulated bunker for raw meal. To eliminate suction in cyclones and bag filters, sluice gates are used.

Cooking of building gypsum - dehydration of gypsum powder takes place in a gypsum boiler with flue gases with a temperature of 600-950 0 С, supplied through the external channels created by the boiler lining and flame tubes. The coolant in these passages is the combustion products of gaseous fuel in the combustion chamber adjacent to the lining.

The coolant, passing through the channels in the boiler lining and flame tubes with a temperature of 250-500 0 С, without touching the material, is carried out of the boiler. Gypsum in the digester does not come into direct contact with gases, its temperature is 121-160 0 С. The process of gypsum firing is accompanied by intensive release of crystallization water. During this period, boiling of gypsum powder is observed.

The gypsum boiler is a vertical steel drum equipped with a stirrer and covered with a lid on top, equipped with pipes for loading the powder and removing the mixture of steam with gypsum particles.

The residence time of the material is regulated by the loading and unloading mode, depending on the required temperature of the material inside the boiler. The material is fed into the boiler by a screw conveyor from the raw meal hopper. Regulation of capacity for loading is carried out by changing the number of revolutions of the screw conveyor. In continuous mode, raw gypsum is loaded continuously above the material level in the boiler through a branch pipe installed on the boiler lid. The vertical discharge chute, placed inside the boiler, is open at the bottom.

The material is unloaded continuously by overflow from the top of the discharge chute. To improve the transportation of gypsum from the lower part of the discharge chute to the top, compressed air is supplied to the lower part with a pressure of 2 atm.

The vacuum in the boiler flue channels is created by the smoke exhauster, which is at the same time the traction unit of the axial hammer mill. Water vapor and gypsum particles formed during the hydration of gypsum in the boiler, as well as excess dust-air mixture of the languishing bin are removed from the boiler. The semi-aqueous gypsum obtained in the gypsum boiler is discharged into the simmering hopper.

Automated control system

Automated control system production of stucco ensures the operation of all elements of technological equipment in automatic, semi-automatic and manual modes to ensure the technological process of production of stucco.

The system is a set of hardware and software that jointly perform the task of controlling a technological process.

System architecture

The control system can be conditionally divided into three levels:

The lower (field) level is represented by sensors and actuators. As sensors in the system there are temperature and pressure sensors, level indicators, motor current monitoring devices, inductive sensors, limit position indicators and additional contacts signaling the state and operating mode of the motors.

The actuators of the system are motors with contactors for direct starting, variable speed motors controlled by variable frequency drives, electromechanical positioners for controlling the throttle valves of smoke exhausters and a switch for the direction of gypsum feed to silos.

At the middle level, the system is represented by a programmable logic controller (PLC) with input-output modules for analog and discrete signals. The PLC is responsible for receiving signals from sensors and issuing control signals to the actuators in accordance with the program laid down in it.

At the top level, the system is represented by a human-machine interface device. This is a computer connected to an industrial network controller and with specialized software installed on it.

Control equipment, switching and control gear are supplied pre-assembled in industrial cabinets. Instrumentation is supplied separately in the original packaging.

All control gear, circuit breakers, contactors and VFDs are manufactured by Siemens.

Programmable logic controller

A Siemens Simatic S7 300 controller with a set of discrete and analog inputs and outputs is used as a PLC in the system, in an amount sufficient to connect all sensors and actuators, and with a reserve determined at the design stage.

The controller must be mounted in a cabinet, which must be installed in a control room with a temperature regime of 0-50 ° C.

A brief description of the algorithms embedded in the controller will be discussed below.

Human-machine interface

An operator station (OS) with an installed Microsoft Windows XP operating system and a Siemens Simatic WinCC SCADA system was used as a human-machine interface system. This station is connected to the PLC by the MPI industrial network to obtain information on the progress of the technological process.

The main functions of the OS are:

• Display of the state of the technological process and equipment in the form of mnemonic diagrams, tables, trends and messages on the computer's dashboard.
• Providing the operator with the opportunity to adjust the technological modes of the installation.
• Manual control of some installation elements.
• Display and archiving of emergency and service messages.
• Storing historical data about the process with the ability to view them.

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Department of technology of building materials, products and structures

Course work

on the topic: "Plant for the production of plaster of paris 300 thousand tons per year"

Completed: student of group B 231

Gatilov S.V.

Checked by: professor

Shmitko E.I.

Voronezh 2017

Introduction

Building mineral binders are powdered materials that, after mixing with water, form a plastic dough that can harden over time as a result of physicochemical processes, that is, pass from a plastic pasty state into a solid stone-like state.

All building mineral binders, depending on their main properties to harden and resist for a long time to the effects of various environmental factors, are divided into two main groups: air and hydraulic. For the correct choice of certain binders for specific purposes, it is necessary to study their composition and properties, be able to determine their quality and make a conclusion about their compliance with technical requirements.

Astringents are the backbone of modern construction.

Gypsum binders are the most effective in technical and economic terms, especially in terms of the specific consumption of raw materials, fuel, electricity and labor per unit of product. The reserves of the original natural raw materials are also unlimited, as well as by-product gypsum-containing materials formed at the enterprises of the chemical industry.

Gypsum binders are divided into: plaster of paris, consisting of a-modification of a hemihydrate; molding plaster of the same composition with improved technical properties; technical (high-strength) gypsum, consisting of b-semi-aqueous gypsum.

Gypsum binders are used mainly for the production of gypsum dry plaster, partition plates and panels, filling elements for interfloor and attic floors of buildings, ventilation ducts and other parts used in the structures of buildings and structures with a relative humidity of not more than 60%. A variety of architectural, fire-retardant, sound-absorbing and similar products are made from gypsum. Wall stones, panels and blocks used in the construction of external walls of low-rise buildings, as well as utility buildings, are made of b-gypsum. In this case, it is necessary to protect the external gypsum structures from moisture.

1. Characteristics of the construction area

In this course project, the city of Novomoskovsk, Tula region, was chosen for the construction of a plant for the production of stucco. Since the Novomoskovsk urban district has the largest stone gypsum deposit in Europe and the region is well developed: metallurgy, mechanical engineering, chemical industry and building materials industry, the construction of such a plant is economically feasible. The gypsum stone will be delivered by road and rail. This is the most economical way. The motorways M4 E 115 "Don", P132 Kaluga - Tula - Mikhailov - Ryazan, Tula - Novomoskovsk, the railways Moscow - Donbass and Syzran - Vyazma, which connect Novomoskovsk with many large cities and others regions of the country.

1.1 Characteristics of products

Gypsum binder in the modification of semi-aqueous gypsum is called stucco. According to GOST 125-79 and GOST 23789-79, it is characterized by the compressive strength of the samples by grades from G-2 to G-25.

The properties of all varieties of gypsum binders, as well as methods for their determination, are regulated by GOST 125-79 “Gypsum binders. Specifications "and GOST 23789-79" Plaster binders. Test methods ".

The true density of stucco varies between 2.6-2.75 g / cm3. Bulk density in a loose state is usually 800-1300, in a compacted state - 1250-1450 kg / m3.

The produced binder has a true density of 2.6 g / cm3, a bulk density of 1300 kg / m3, fineness of grinding to a residue on a sieve No. 02 not more than 10%.

The hardened gypsum is a solid body with high porosity, reaching 40-60% or more (with an increase in the mixing water, the porosity of the gypsum product increases, and the strength decreases).

Plaster of paris is a fast-setting binder. According to GOST 125-79, depending on the setting time, three types of gypsum binders are distinguished, classified as follows:

Start of setting End of setting

not earlier, min not later, min

Fast hardening 2 15

Normal hardening 6 30

Slow hardening 20 not standardized

The quick setting of semi-aqueous gypsum is in most cases its positive property, which allows quick removal of products from the molds. However, in some cases, fast setting is undesirable. To regulate the setting time, various additives are introduced into the gypsum during mixing.

According to GOST 125-79, gypsum binders, depending on the ultimate strength in bending and compression, are divided into grades G-2 - G-25. The strength of gypsum binders is determined in accordance with the requirements of GOST 23789-79. The dependence of the strength of gypsum and gypsum products on moisture content is their significant disadvantage.

The brand of gypsum produced by us is G-10, G-13.

Gypsum binders in the hardened state, as well as products made from them, exhibit large plastic deformations, especially with prolonged action of bending loads. These deformations are relatively small if the product is completely dry. The significant susceptibility of hardened gypsum to creep deformations severely limits its use in bending structures.

Products made of semi-aqueous gypsum are characterized by high durability when used in an air-dry environment.

Fire resistant gypsum products. They warm up relatively slowly and break down only after 6-8 hours of heating, i.e. for a duration of fire that is unlikely. Therefore, gypsum products are recommended as fire retardant coatings.

1.2 Characteristics of raw materials

The starting materials for the production of binders are various rocks and some by-products of a number of industries.

For the production of gypsum binders, gypsum rocks are used, consisting mainly of gypsum dihydrate CaSO4 2H2O. For the same purpose, phosphogypsum is also used, which is a waste of the production of phosphorus fertilizers.

Natural dihydrate gypsum is a rock of sedimentary origin, composed mainly of large or small crystals of calcium sulfate CaSO4 2H2O.

Gypsum rocks usually contain a certain amount of impurities of clay, sand, limestone, bituminous substances and others. The chemical composition of gypsum from the Novomoskovskoye deposit in the Tula region is shown in Table 1.

Table 1- Chemical composition of natural gypsum from the Novomoskovskoye deposit

Pure gypsum is white, impurities give it different shades: iron oxides paint it yellowish-brown, organic impurities - gray, etc. A small amount of impurities evenly distributed in the gypsum does not significantly impair the quality of the binders. Large inclusions have a harmful effect.

According to GOST 4013-82, gypsum stone for the production of gypsum binders must contain at least 95% of dihydrate gypsum in raw materials of the 1st grade, at least 90% in raw materials of the 2nd grade and at least 80 and 70% in raw materials 3- and 4 -th varieties. The gypsum rocks of the Novomoskovskoye deposit contain up to 1-10% of impurities.

The average density of gypsum stone depends on the amount and type of impurities and is 2.2-2.4 g / cm3.

Bulk density of gypsum crushed stone 1200-1400 kg / m3, humidity fluctuates within significant limits of 3-5%. The water content in different batches of gypsum stone is not the same and depends on its physical properties, relative humidity, season and storage conditions.

As starting materials for the production of gypsum binders, it is rational to use by-products (waste) of the chemical industry - phosphogypsum, borogypsum, fluorogypsum. In the form of phosphogypsum, borogypsum, fluorogypsum, etc. at the respective enterprises they are obtained in large quantities and are almost completely sent to dumps. Dumps occupy significant areas of land. Dumping of waste into dumps is especially undesirable due to the harm caused to the environment. The reason for this is, in particular, the presence of harmful impurities in the waste (sulfuric, phosphoric acids, fluoride compounds in the amount of 1-2.5%).

Phosphogypsum is formed during the processing of natural apatite and phosphorite rocks into fertilizer, borogypsum and fluorohypsum - in the production of boric acid and fluoride compounds.

All waste mainly consists of dihydrate, semi-aqueous gypsum, anhydrite, the total content of which ranges from 80 to 98% by weight.

In the production of plaster of paris at our plant, we will use gypsum stone delivered from the Novomoskovskoye deposit, with an initial particle size of 500 mm, as a starting material.

1.3 Selection and justification of the general technology for the production of a binder

The main component of plaster of paris is a two-water gypsum stone, which is mined in a quarry using an excavator and delivered to the plant by road and rail. In our case, this is the most profitable method of delivering raw materials from the point of view of economic costs. Pieces of gypsum stone with a size of 500 mm and a moisture content of 4% are unloaded into a receiving hopper, from where they are sent to a closed-type warehouse. From the raw material bin, the gypsum stone is sent to the crushing and sorting shop, where it is crushed and then sorted.

Crushing is carried out in a jaw crusher, as it is a rather coarse material of medium strength. We accept multi-stage crushing, namely, in two stages, since in practice two-stage crushing is most often used, as it is more economical in comparison with a multi-stage single-line scheme. Then the obtained gypsum is divided into fractions by screening and sent to the next workshop for firing.

Roasting is the main technological operation in the production of binders.

An endothermic reaction occurs during firing

CaSO4 2H2O = CaSO4 0.5H2O + 1.5H2O

with the absorption of 588 kJ of heat per 1 kg of hemihydrate.

The main methods of production of stucco, currently used, can be divided into the following three groups, characterized by: preliminary drying and grinding of raw materials into powder, followed by dehydration of gypsum (gypsum firing in gypsum boilers); by combining the operations of drying, grinding and firing two-water gypsum; burning gypsum in the form of pieces of various sizes in shaft, rotating, chamber and other furnaces. As a result of firing, the dihydrate calcium sulfate contained in the gypsum stone is converted into semi-aqueous.

Gypsum boilers are widely used for heat treatment of finely ground gypsum stone.

In a boiler, gypsum is fired as follows. The duration of the cooking process depends on the size of the boiler, temperature, humidity and partial dehydration of the gypsum entering it. The duration of the cooking process ranges from 1 to 3 hours, while the cooking temperature is 140 ° C. Gypsum in digesters is intensively mixed and evenly heated, which ensures a homogeneous product of high quality. Gypsum boilers have a volume of 2.5-15m3; the power of the electric motors of the boiler drive is 2.8-20kW.

The disadvantage of gypsum boilers is the frequency of operation, which limits their performance, complicates the automation of production processes.

Currently, gypsum in pieces is fired in rotary kilns.

The rotary kilns for stucco firing are drums.

The drying drum is a welded steel cylinder rotating on support rollers. The drum is installed with an inclination to the horizon of 3-50 and is driven into rotation by an electric motor. If the direction of movement of hot gases and materials in the furnace coincides, then the drum works according to the principle of forward flow, if the direction does not coincide, according to the principle of counterflow. The second scheme is characterized by reduced fuel consumption.

Gypsum crushed stone 10-20 and 20-35 mm is usually fed to the drying drum for firing. Fractions 10-20 and 20-35 mm are fired separately. Firing is carried out at a temperature of 1600C. Fraction 0-10mm is a waste product if its content is not more than 5%. If its content is more than 5%, then a waste-free production can be created by sending crushed stone of this fraction to a gypsum boiler and firing at a temperature of 140 ° C.

The burnt gypsum grit enters the feed hopper of the ball mill or is sent to the holding hopper. The nibs are ground to a residue on a sieve No. 02 of no more than 10-12%. Most often they are ground in one- or two-chamber ball mills.

Gypsum is usually stored in round silos, where it is delivered by pneumatic transport.

Technological processes for the production of gypsum with its roasting in rotary kilns are continuous, and therefore it is easy to carry out their automatic control. This method of producing gypsum is very economical. Fuel consumption ranges from 45-50kg, electricity 15-20kWh per 1 ton.

Building gypsum, obtained by roasting in rotary kilns, has a reduced water demand (48-55%) when obtaining a dough of normal density compared to gypsum from digesters (60-65%), which is partly due to the use of ball mills for grinding, giving the particles a tabular shape ... In addition, when gypsum is milled in mills at 120-130 ° C, gypsum residues are dehydrated and its modification composition is leveled. This method of gypsum production is used on a significant scale in domestic and foreign practice.

1.4 Determination of the operating mode of the enterprise

In the production of plaster of paris, natural dihydrate gypsum stone is used as the main component.

c-gypsum is obtained by firing gypsum stone, previously ground and sorted, in rotary kilns at a temperature of 1600C, in gypsum boilers at a temperature of 1400C.

Due to the fact that drying drums are continuously operating units, a three-shift operation should be provided.

With continuous operation, the annual fund of time of the enterprise is calculated by the formula:

Tf.pr. = (365-n) 3 8 = (365-15) 3 8 = 8400 h / year

where n is the number of days for overhaul (taken equal to 15 days).

Table 2- Production program of an enterprise for the production of a binder

The need for raw materials according to the standards of technological design from the condition of the specific consumption of 1.25 t / t of commercial gypsum, i.e.

36 1.25 = 45 t / h

1.5 Calculation of traffic flows

Table 3-calculation of traffic flows in the production of plaster of paris

Functional diagram of the production of plaster of paris

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1.6 design of warehouses for raw materials, semi-finished products and finished products

Warehouses are designed on the basis of technological design standards, taking into account the amount of cargo flows and the accepted conditions for organizing the operation of the technological line. Raw materials are supplied to the production shops from the factory's raw material warehouses. The choice of warehouse types is determined by technological and technical and economic indicators. Basically, closed-type warehouses are used, which ensures the stability of the quality characteristics of the stored material. With the correct operation of the warehouse, fast unloading of arriving vehicles, uninterrupted supply of raw materials to production, and the lowest cost of transport operations are ensured.

The size of the warehouses should be the minimum required, which increases the use of the company's working capital. According to the norms of stock of material in the warehouses of raw materials, the stock in the warehouse is:

current - 2 days,

insurance - 1 day.

For finished products:

current - 2 days

insurance -

Based on this data, the current volume of raw materials stored in the warehouse is calculated using the formula:

Vmatter = Qday 3

where Qday. - daily material consumption, m3;

3 - total stock of material in the warehouse, days.

Thus, the volume of gypsum stone stored in the warehouse is:

V gypsum. = 2193.85 3 = 6582 m3.

The warehouse volume for the calculated raw material volume is calculated using the formula:

Vcl. = Vmatter / K,

where K is the utilization rate of the warehouse volume (K = 0.8)

Gypsum warehouse volume

Vfl. = 6582 / 0.8 = 8227.5 m3

The width (in) of the warehouse is assigned based on its accepted height, taking into account the angle of repose of the stored material.

The warehouse length is determined by the formula:

Lspl. = Vspl. / Fspl.,

where Fcl. - part of the warehouse cross-section filled with material

(determined by thumbnail representation).

Lfl. = 8227.5 / 90 = 91.4 m

Let's take a warehouse length of 96 m.

1.7 Calculation of finished goods warehouses

The plaster of paris is stored in a silo-type warehouse. The stock in the warehouse is made for four days.

Silo storage volume:

Vsil. = A 4/365 K g,

where Vsil.- the volume of silo warehouses,

K is the utilization rate of the warehouse volume, K = 0.9;

4 - total stock of material in the warehouse, days.

A - plant productivity, t / year;

g - average bulk density of gypsum loaded into silos.

Vsil. = 700000 4/365 0.9 1.3 = 655.6 m3;

The number of cans is 12 pieces, then the volume of one can

V1 = Vsil / 12 = 655.6 / 12 = 54.63 m3

Can height:

where d is the diameter of the can, d = 8m;

h = 4 54.63 / 3.14 82 = 1.08m.

2. Formation of initial data for the calculation

The initial data for calculating the apparatus are presented in Table 7.

Table 7- Initial data for calculating the drying drum, dried material - gypsum stone

2.1 Material balance of drying and dehydration processes

Drying drum performance for gypsum stone:

Pg.k. = P / 100-In.with 100, (1)

where P is the productivity of the drying drum in terms of in-hemihydrate, kg / h;

Incoming st. - removed chemically bound water (1.5H2O) by dehydration reaction relative to gypsum dihydrate,% (wt.).

Pg.k. = 66331 100 = 78740.5 kg / h

For 4 drums P = 16625 kg / h, Pg.c. = 19735.3 kg / h

Amount of chemically bound water evaporated:

Wх.св. = Pg.k.-P (2)

Wx.w. = 19735.3-16625 = 3110.3 kg / h

Amount of chemically unbound water evaporated

Wn.w = Pg.k. sc, (3)

where wn is the moisture content of the incoming gypsum stone,%.

Wn.w = 19735.3. 5 = 986.77 kg / h

Total amount of evaporated water:

W = Wx.w. + Wn.sv. , (4)

W = 3110.3 + 986.77 = 4097.07 kg / h

2.2 Calculation of the combustion process of fuel and parameters of combustion products at the entrance to the dryer

Most dryers use a mixture of atmospheric air and flue gases as a drying agent, which is obtained by burning fuel in its own combustion device. Such a mixture in the technical and reference literature is called fuel combustion products.

First, based on the composition of natural gas and the stoichiometric ratios of the combustion reactions of each combustible gas component, the amount of combustion products (CO2 and H2O) and the amount of oxygen (O2) required for combustion are calculated. This calculation is presented in table 8.

Table 8- Calculation of natural gas combustion (made for 100 m3 of gas)

Determination of the actual temperature of gas combustion at b = 1.0:

td = Qnr · s + CT · tT + b · Vt.v. Io · tvo, (5)

VCO2 СCO2 + VH2O CH2O + VN2 CN2

where Qнр - the highest heat of combustion of fuel, Qнр = 37385 kJ / mі;

h - furnace efficiency, 0.88 - 0.9 is taken;

tT is the temperature of the fuel supplied for combustion, tT = 10 ° C;

ST is the specific heat capacity of the fuel at tT, ST = 1.56 kJ / mі · K;

Vt.v. - theoretical volume of air (at b = 1.0), Vt.v. = 8.86 mі;

two is the temperature of the air entering the combustion, tbo = 10 ° С;

Svo - specific heat capacity of air at two, Svo = 1.29 kJ / mі · K;

VCO2, VH2O, VN2 - volumes of gases in the composition of flue gases formed from the combustion of 1 m3 of combustible gas, VCO2 = 1.06 m3, VH2O = 2.11 m3, VN2 = 7.8 m3;

СCO2, CH2O, CN2 - specific heat capacities of the flue gas components, their values ​​are determined according to the fuel combustion temperature.

Since when choosing the values ​​of the specific heat capacity td is not known, we conditionally assign a temperature in the range of 1500 - 2000 ° C, and calculate the approximate value of td. Let us take td = 1800 ° C, then СCO2 = 2.40 kJ / mі K, CH2O = 1.92 kJ / mі K, CN2 = 1.47 kJ / mі K.

td = 37385 0.9 + 1.56 10 + 1 8.86 1.29 10 = 1864 ° C.

1.06 2.4 + 2.11 1.92 + 7.8 1.47

At td = 1864 ° C: СCO2 = 2.18 kJ / mі K, CH2O = 1.7 kJ / mі K, CN2 = 1.38 kJ / mі K.

The total excess air ratio (b) is determined as:

b = bg + bd, (6)

where bg is the coefficient of excess air for combustion;

bd - additional excess air factor (to reduce

flue gas temperature.

The additional excess air ratio is calculated from the heat balance equation:

(VCO2 СCO2 + VH2O CH2O + VN2 CN2) td- (VCO2 СCO2 + VH2O CH2O + VN2 CN2) t1, (7)

bd = VТV CВ1

where V is the volume of dry combustion products formed from 1 m3 of gas at b = 1.0;

С - specific heat of dry combustion products, kJ / mі · К;

t1 - temperature of combustion products at the entrance to the dryer, t1 = 900 ° С;

Sv1 - specific heat capacity of air at temperature t1, Sv1 = 1.38 kJ / mі · K;

needles - moisture content of the air supplied for combustion, needles = 0.005 kg / kg;

svo - density of air supplied for combustion, svo = 1.29 kg / m³;

ro - heat of vaporization, at t = 0 ° С ro = 2481 kJ / kg;

CH2O - specific heat of water vapor at t1, CH2O = 1.7 kJ / mі · K;

сH2O - density of water vapor under normal conditions, сH2O = 0.803 kg / mі.

Taking into account the accepted designations:

(VCO2 СCO2 + VH2O CH2O + VN2 CN2) td = (1.06 2.4 + 2.11 1.92 + 7.8 1.47) 1864 = 33666.08

(VCO2 СCO2 + VH2O CH2O + VN2 CN2) t1 = (1.06 2.18 + 2.11 1.7 + 7.8 1.38) 900 = 14995.62

VTV CВ1 · tВ1 = 8.86 1.7 · 900 = 13555.8

Vt.v. free xvo t1 CH2O / сH2O = 8.86. · 1.29 · 0.005 · 1.7 10 / 0.803 = 1.21

Vt.v. · Ow · tvo = 8.86. · 1.29 10 = 114.29

bd = (33666.08-14995.62) / (13555.8-114.29 + 1.21) = 1.39,

b = 1.00 + 1.39 = 2.39

where Gn is the mass of water vapor in combustion products,

G is the mass of dry gases;

x1 = 178.36 = 0.061 kg / kg.

The enthalpy of gases at the entrance to the dryer in kJ / kg can be determined by the formula:

I1 = Qnr · s + CT · tT + b · Vt.v. Io · tvo, (9)

where b is the total excess air ratio;

Vt.v. - theoretical air consumption for combustion of 1 m3 of gas (at b = 1.0), m3 / m3;

G - mass of dry combustion products, kg / mі.

I1 = 37385 0.9 + 1.56 10 + 2.39 8.86 1.29 10 = 1152 kJ / kg.

2.3 Representation of the drying process in the I-x diagram, determination of combustion parameters at the outlet of the dryer, determination of the drying agent and fuel consumption

The plotting of the drying process begins with plotting point A, corresponding to the parameters of the source air to = 100C and tso = 65%. Then the position of point B is determined (t1 = 9000C, x1 = 0.061 kg / kg, I1 = 1152 kJ / kg), corresponding to the calculated values ​​of the parameters of combustion products I1 and x1 and temperature t1.

Point C corresponds to the intersection of the line I1 = const and t2 = const. Point C corresponds to x2T = 0.36kg / kg. We will use this value to determine the consumption of the drying agent, but first, using (4), we will determine the moisture capacity of the drying drum (W):

W = 4097.07 kg / h

The consumption of the drying agent L passing through the drying apparatus in the theoretical drying process is equal to:

L = W / (x2T-x1)

or L = 4097.07 / (0.36-0.061) = 19899.67 m3 / h.

To plot the practical drying process on the I-x diagram, it is necessary to determine the value of the decrease (loss) in the enthalpy (Ip) of the combustion products at the outlet of the dryer, which can be represented as

Iп = qn + (qm + qx.p.) / L, (10)

where qm is the heat consumption for heating the material, kJ / kg;

qn - heat losses to the environment through the walls and outer

drying drum thermal insulation, kJ / kg;

qx.p is the heat consumption for the chemical reaction of dehydration of gypsum dihydrate.

In turn

qm = Pg.k. (tm2 - tm1) Cm + Wp (tsm - tm1) Sv, (11)

where Cm is the specific heat of the material being dried, kJ / (kg0C);

Wp is the moisture performance of the dryer provided that the material is completely dry:

Wp = Pg.c. sc / 100, (12)

tcm is the average temperature of the material in the dryer, it can be determined as

tcm = tm1 + 2/3 (tm2 - tm1).

We get

Wp = 19735.3. 5/100 = 5950 kg / h;

tcm = 10 + 2/3 (80 - 10) = 570C;

qm = 19735.3. (80 - 10) 0.9 + 5950 (57 - 10) 4.19 = 8668733.5 kJ / h.

qn = 0.07 I1 = 0.07 1152 = 80.64 kJ / kg;

qx.p = Pg.c. · Qx.r. , (13)

where Qх.р-endo-effect of a chemical reaction (Qх.р = 580.7 kJ / kg).

qx.p = 19735.3.580.7 = 11460288.71 kJ / kg

The amount of enthalpy loss:

Ip = 80.64+ (8668733.5+ 11460288.71) / 19899.67 = 1092.17 kJ / kg

Let's return to the I-x-diagram and set aside from point C vertically down the value of Ip in the scale of the coordinate axis. We get T. D. We connect this point with the original point B, at the intersection with t2 = 1600С, х2 = 0.184 kg / kg.

The actual consumption of wet combustion products leaving the dryer, calculated as dry gases, will be equal to:

by mass - L = W / x2-x, (14)

by volume - Vc = L / dry,

where dry is the density of dry combustion products (table).

For the case under consideration, the flow rate will be:

L = 4097.07 / 0.184-0.061 = 33309.5 kg / h

Vc = 33309.5 / 1.198 = 27804.26 m3 / h

Natural gas consumption in the furnace will be:

B = I1 L / QHP YT, (15)

where JT is the efficiency furnace, you can take UT = 0.9.

For the considered example

B = 1152 33309.5 / 37385 0.9 = 1140.5 m3 / h.

Specific fuel consumption relative to moisture removed from matter:

Woodw = W / W = 1140.5 / 4097.07 = 0.278 m3 / h = 278 m3 / t.

The amount of air required for fuel combustion:

Vвг = VТВ. В. (16)

In our case

Vwg = 8.86. 1140.5 = 10104.83 m3 / h.

The amount of air required to dilute the flue gases:

Vvr = (b-1) VTV (17)

In our case: Vvr = (2.39-1) 8.86 11405.83 = 14045.71 m3 / h.

Total air quantity:

Vv = Vvg + Vvr, (18)

In our case: Vw = 10104.83 + 14045.71 = 24150.54 m3 / h

Amount of water vapor in exhaust gases from the dryer:

VH2Otot = VH2Ong · B + W / 0.803 (19)

VН2Опг is the volume of water vapor in combustion products at a calculated (b = 2.39) value

excess air ratio, m3 / m3,

We get: VH2Otot = 2.2212 1140.5 + 4097.07 / 0.803 = 7635.48 m3 / h

The volume of wet combustion products leaving the dryer:

Lwl = L + VH2 (twenty)

In our case: Lvl = 33309.5 + 7635.48 = 40944.98 m3 / h.

Volume ratio of dry gases (v1) and water vapor (v2):

y1 = L / Lwl; y2 = VH2Otot / Lwl. (21)

In our case:

y1 = 33309.5 / 40944.98 = 0.814;

y2 = 7635.48 / 40944.98 = 0.186.

Density (under normal conditions) of a mixture of wet gases:

svl = y1 dry + y2 spv, (22)

where dry is the density of dry combustion products, kg / m3;

csv is the density of water vapor, kg / m3.

In our case: dvl = 0.814 1.198 + 0.186 0.803 = 1.125 kg / m3.

Density of wet combustion products at temperature t1:

ct1 = svl 273 / (273+ t1). (23)

In our case: ct1 = 1.125 273 / (273+ 900) = 0.262 kg / m3.

Actual volume of humid gases entering the dryer at t1 (Vwl):

Vvl1 = Lvl svl / ct1. (24)

In our case: Vvl1 = 40944.98 1.125 / 0.262 = 143027.4 m3 / h

At the outlet of the dryer at t2 = 1600С

ct2 = 1.125 273 / (273+ 160) = 0.709 kg / m3.

Vw2 = 40944.98 1.125 / 0.709 = 28854 m3 / h = 8.2 m3 / s.

2.4 Determination of dryer parameters

2.4.1 Determination of the intensity of the drying process and the volume of the drying drum

The volume of the drying space Vb consists of the volume Vn required to warm up the wet material to the wet bulb temperature, at which intensive evaporation of moisture begins, and the volume Vc required for the evaporation of moisture:

Vb = Vn + Vc. (25)

The main share falls on the volume Vс.

To calculate the volume of the drying space, the formula is applicable:

Vs = W ", (26) vsh · Dx" cf

where W "is the moisture performance of the dryer, W" = W / 3600 = 1.138 kg / s;

product (vsh · Dx "cf) serves as a measure of the intensity of the evaporation process; it includes:

vsh - coefficient of volumetric moisture yield, s-1;

Dx "cf - the average driving force of the mass transfer process, kg / mі.

The volumetric moisture-yielding coefficient vsh can be calculated using the empirical equation:

wsch = 1.6 10-2 (wav ssr) 0.9 n0.7 w0.54 Po, (27)

C ssr (Ro - Rsr)

where wav is the average speed of the drying agent (it is taken no more than 2-3 m / s / 5 /);

сср - the average density of the drying agent at the average operating temperature in the drum, kg / m3;

n - drum rotation frequency, usually does not exceed 8 min-1;

в - the degree of filling the volume of the drum with the material to be dried, taken according to Appendix 8/5 /: for lifting-blade transfer devices в = 12%;

Po - pressure at which drying is carried out, Po = 105 Pa;

C is the specific heat capacity of the drying agent at the average operating temperature in the drum, kJ / mі · K; C = 1.32 kJ / mі · K;

Рср - average partial pressure of water vapor in the drying drum, Pa.

The average density of the drying agent ssr is determined at the average temperature of the gases:

tav = t1 + t2 = 900 ° C + 160 ° C = 530 ° C;

Accordingly: ssr = M. To = co. That, (28)

22.4 To + tav To + tav

where ω = mass of combustion products = 3123.8 = 1.26 kg / m3;

volume of combustion products 2477.03

csr = 1.26 273 = 0.43 kg / m2.

The average partial pressure of water vapor is defined as:

Рср = Р1 + Р2, (29)

where Р1 is the partial pressure of water vapor in the gas at the entrance to the dryer, Pa;

P2 is the partial pressure of water vapor in the gas at the outlet of the dryer, Pa;

The values ​​of P1 and P2 are determined from the I-x diagram, respectively, for points by the formulas:

P1 = (x1 / 18) 105 and P2 = (x2 / 18) 105, (30)

1 / Md.y. + x1 / 18 1 / Md.y. + x2 / 18

where Md.y. - average molar mass of flue gases:

MDG = 22.4 sdg. = 22.4 * 1.26 = 28.22 kg / mol;

P1 = (0.061 / 18) 105 = 0.0875 105 Pa;

1/28,22 + 0,061/18

P2 = (0.184 / 18) 105 = 0.22 105 Pa;

1/28,22 + 0,184/18

Pav = 0.0875 105 Pa + 0.22 105 Pa = 0.154 105 Pa.

The specific heat of combustion products at an average temperature can be determined as

С = уСО2 ССО2 + уН2О СН2О + уО2 СО2 + уN2 СN2, (31)

Thus,

C = 0.045 2 + 0.0897 1.33 + 0.1161 1.4 + 0.7517 1.33 = 1.3673 kJ / m3.

wsc = 1.6 · 10-2 · (3 · 0.43 kg / mі) 0.9 · (3) 0.7 · 100.54 · 105 = 0.3022 s-1.

1.37 · 0.43 kg / mі · (105 - 0.15 · 105)

The driving force for mass transfer can be determined from the equation:

Dx "cf = Dx" n - Dx "k, (32)

2,3? N (Dx "n / Dx" k)

where Dx "n = x1 * - x1 is the driving force at the beginning of the drying process, kg / kg;

Дх "к = х2 * - х2 - driving force at the end of the drying process, kg / kg;

х1 *, х2 * - equilibrium moisture content at the entrance to the dryer and at the exit from it, kg / kg; their values ​​are determined by the I-x diagram according to the points of intersection of the lines tmt1 (temperature of the wet thermometer for the initial state) and c = 100%, tmt2 and c = 100%;

x1 * = 0.44; x2 * = 0.21;

Dx "n = 0.44 - 0.061 = 0.379;

Dx "k = 0.21 - 0.184 = 0.026;

Dx "cf = 0.379 - 0.026 = 0.132 kg / mі.

2.31 × n (0.278 / 0.016)

Finally:

Vc = 1.138 = 66.1 mі.

The volume of the drum Vn required to warm up the wet material can be determined from the following heat transfer equation:

where Qn is the amount of heat required to heat the material to a temperature

Кх - volumetric heat transfer coefficient, kW / mіK;

Dtav - average temperature difference, ° С.

Heat consumption can be determined from the heat balance equation:

Qn = M2 Sm (tmt - tm1) + W Svd (tmt1 - tm1), (34)

where M2 is the mass of the material leaving the dryer, M2 = 4.62 kg / h;

Cm - specific heat of the material, Cm = 0.92 kJ / kg · K;

tm1 is the temperature of the material at the entrance to the dryer, tm1 = 10 ° С;

tmt - average temperature of a “wet” thermometer:

tmt = tmt1 + tmt2, (35)

respectively, tmt1 and tmt2 - the temperature of the “wet” thermometer at the beginning and at the end of the dryer,

tmt1 = 78 ° C, tmt2 = 70 ° C,

tmt = 78 + 70 = 74 ° C;

Svd - specific heat capacity of water, Svd = 4.19 kJ / kg · K.

Qn = 4.62 0.92 (74 ° C - 10 ° C) + 0.25 4.19 (74 ° C - 10 ° C) = 333.71 kJ / s

The volumetric heat transfer coefficient can be determined from the following equation:

Kx = 16 (wav · ssr) 0.9 · n0.7 · b0.54; (36)

Kx = 16 (3 0.43) 0.9 (3) 0.7 100.54 = 0.151 kW / mі K.

The average temperature difference can be defined as:

Dtav = (t1 - tm1) + (t2 - tm2), (37)

where t1 and t2 are the temperature of the drying agent at the inlet and outlet of the dryer;

tm1 and tm2 are the temperature of the material at the entrance and exit from the dryer;

Dtav = (900 ° C - 10 ° C) + (160 ° C - 80 ° C) = 485 ° C.

Drum volume required to heat wet material:

Vn = 333.7 = 4.6 mі.

Drum total volume

Vb = Vn + Vc = 4.6 + 66.1 = 70.7 mі.

2.4.2 Determination of the geometric dimensions of the drum and the choice of a serial brand of equipment

To determine the inner diameter of a drum dryer (DB), use the following formula:

DB = 0.0188 · L · Vvg. ,

where L is the hourly consumption of dry heat carrier, kg / h;

Vвг - the volume of wet gases at the end of the drum per 1 kg of dry gases contained in them, m / kg, it can be calculated as:

Vвг = x2 / сH2O + 1 / сср,

where сH2O and сср - density of water vapor and dry heat carrier at an average temperature of gases in the drum tср; ccr = 1.198 kg / m2; cH2O = 0.803 kg / m³;

V century = 0.184 + 1 = 1.06 m3 / kg;

в - the degree of filling the volume with material in fractions, в = 0.12;

w is the speed of the drying agent at the end of the drum (2-3 m / s).

DB = 0.0188 33309.5 1.06 = 2.17 m.

The length of the drum (Lb), m, is determined through the volume: Vb = rdb / Lb or

Lb = 4 70.7 = 19.13 m.

Determination of the angle b "tilt of the drum to the horizon:

b "= 30 · Lb + 0.007w. 180,

where f is the residence time of the material in the drum, s;

f = 3600 M + fx.r.

where M is the amount of dried material in the drum, kg; it can be calculated as M = Vb · v · cm, where cm is the density of the material (bulk), kg / mі;

M = 70.7 * 0.1 * 1300 kg / m2 = 9191 kg;

M2 is the mass of material leaving the dryer, kg / h, M2 = 16625 kg / h;

W is the amount of evaporated water, W = 4097.07 kg / h;

fc.r.-time for a chemical reaction, fc.r. = 0.7 f;

f = 3600 9191 = 1970 +0.07 1970 = 2108 s

16625 + (4097,07 /2)

b "= 30 * 19.13 + 0.007 * 3.380 = 3.81 °.

2.17 · 3 · 2108 3.14

The drum rotation frequency n, min-1, is determined by the formula:

n = k Lb 60,

where k is a coefficient equal to k? 0.4.

n = 0.4 * 19.13 * 60 = 4.386 min-1.

2108 2.17 tan 3.81 °

In accordance with the obtained overall dimensions and technical characteristics of the drying drum, a factory-grade drying drum was selected, the technical characteristics of which are presented in Table 9 (Table 23/4 /).

Table 9. Technical characteristics of the drying drum SMTs-428.2

2.4.4 Selection and calculation of auxiliary devices

Auxiliaries include combustion devices, including gas blowers, gaseous fuel burners, dust cyclones and traction devices.

In the developed project, cyclones and fans are subject to calculation and selection.

2.4.4.1 Selection and design of cyclones and filters

The main operational characteristic of the cyclone is its gas productivity V, m / s. It is on this characteristic that the initial choice of the type of cyclone is made. The choice and calculation of the cyclone should be carried out in a complex, taking into account the input characteristics (productivity, dust load) of the filter mated with it. Therefore, it is advisable to select the filter / 4 / first.

The filter is a fine filter. In small industries, mainly fabric bag filters are used, the degree of purification in which reaches 99.9%. Therefore, further selection of the filter will concern only bag filters of the FV type.

The choice of a bag filter is made according to its performance, which should not be lower than the volumetric flow rate of gas leaving the drying drum.

In our case, according to those given in clause 6.4.5. calculations:

Vw2 = 28854 m3 / h = 8.2 m3 / s.

According to Appendix 6/4 /, two filters of the FV-90 type with a capacity of 4.5 m3 / s, a filtering surface of 90 m2 are selected, the technical characteristics of which are presented in table 10.

Table 10. Technical characteristics of the FV-90 filter.

Then the permissible dust load on the filter / 13 / is calculated:

Mon = Pud Sph,

where Pud is the specific dust load on the filter (does not exceed 1 kg / m / h);

Sf is the total area of ​​the filtering surface;

Mon = 1 90 = 90 kg / h.

The maximum allowable content (by weight) of dust in gases leaving the cyclone and entering the filter is / 4 /:

Gvkhf = 90 = 0.0062 kg / mі = 6.2 g / mі.

This value should be guided by when choosing and calculating cyclones.

The original brand of cyclone is selected according to its capacity, which should not be lower than the amount of wet gases leaving the drying drum.

According to the productivity Vvl2 = 4.2 m / s, you can initially select a group of six cyclones of the TsN type (appendix 7/4 /) with a diameter of 700 mm.

Next, you should determine the content of dust in the combustion products leaving the drying drum, and evaluate the degree of gas cleaning in the cyclone of the selected diameter. If the obtained value of Gout turns out to be higher than that obtained above Gin, then you should check for this characteristic of another, smaller diameter, cyclone, etc.

Gvkhts = 45 - 80 g / mі.

The accepted value should be distributed among fractions, performing all calculations in the form of table 11.

Based on the definition of the partial fractional purification factor as

zFi = GulFi 100,

where GвхФi - dust content of the i-th fraction at the entrance to the cyclone, g / mі;

Gulfi - the amount of dust caught in the cyclone,

the fractional amount of dust captured is determined:

GulФi = ЗФi · ГвхФi.

Thus, the final value of Gout will be equal to:

Gout = Gin +? Gulfi,

where n is the number of isolated fractions.

Table 11- Material balance of the dust cleaning process in a cyclone of the TsN type, D = 700 mm.

Purification factor of the entire stream:

s = Gin - Gout * 100 = 80 - 4.76 * 100 = 94.05%.

Since in Appendix 9/4 / the partial cleaning factors are given for a cyclone with a diameter of 600 mm, the result obtained for Yu must be clarified using the diagram in Appendix 10/4 /.

The refined value of the cleaning factor U "= 92%

The result obtained satisfies the condition Gout? Gvkhf, or

4.76 g / m2? 6.2 g / m³, and therefore the cyclone and filter are correct.

2.4.4.2 Selection of traction devices

The design characteristics when choosing fans are:

- productivity;

- generated pressure (or head).

The performance should correspond to the value Vvl2 = 28854 m3 / h.

The total pressure of the DR fan must exceed the hydraulic resistance of all auxiliary devices (DRVU), which can be defined as:

DRvu = DRts + DRf + DRs,

where DRts is the hydraulic resistance of the cyclone, Pa;

DRts = about · mixtures · wцІ,

where o is the coefficient of hydraulic resistance, for cyclones of the TsN-15 brand:

mixture - the density of dry combustion products, taken according to table. eight,

mixture = 0.71 kg / m2;

wc is the conditional (fictitious) gas velocity in the cyclone (referred to the entire section), it can be defined as:

wc = V "vlfact · 4,

where D is the diameter of the cyclone, D = 700 mm = 0.7 m;

V "vl - gas consumption per one cyclone,

V "lfact = 8.2 = 1.37 m / s;

wts = 1.37 4 = 3.56 m / s.

Thus, for one cyclone:

DR1c = 90 0.71 (3.56) I = 404.9 Pa,

and for six cyclones: DR6ts = 6 404.9 Pa = 1620 Pa.

DRf is the hydraulic resistance of the filter, Pa, for one filter of the FV-45 brand, according to table 10, DR1f = 800 Pa, and for two filters: DR2f = 2 800 Pa = = 1600 Pa.

DRs - hydraulic resistance in the network, Pa, it can be taken approximately as 5% of (DR6ts + DR2f), i.e.:

DRs = 0.05 (1600 + 1620) = 161 Pa.

We finally get:

DRvu = 1620 + 1600 + 161 = 3381 Pa.

Taking into account the characteristics Vvlfact = 28854 m3 / h and DRvu = 3381 Pa, according to Appendix 11/3 /, two smoke exhausters of the D-0.7-37 series of standard size D-12 are adopted, the technical characteristics of which are presented in table 12.

Table 12. Technical characteristics of the D-0.7-37 series smoke exhauster, standard size D-12.

3. Justification and selection of equipment, calculation of its needs

The calculation of the number (n) of the required technological equipment is made on the basis of comparing the traffic flow at a certain technological stage with the passport capacity of the received equipment and is determined by the formula:

n = L / P, pcs, (2)

where G is the value of the traffic flow, t / h

P - passport capacity of a piece of equipment, t / h.

3.1 Selection and calculation of the main technological equipment

In the production of plaster of paris, the following types of technological equipment are used: equipment for crushing material; equipment for sorting material; equipment for material grinding; equipment for material firing; equipment for dosing and transporting material; auxiliary equipment; lifting equipment.

3.2 Selection and calculation of the equipment of the primary unit ...

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Search for an investor for the construction of a gypsum plant in the Moscow region based on the production of high-strength gypsum from waste phosphogypsum.

I am looking for an investor for the construction of a gypsum plant in the Moscow region.
It is based on the production of high-strength gypsum from waste phosphogypsum.
On the basis of the obtained gypsum (will be sold as a raw material for dry building mixtures), it is proposed to build a line of popular gypsum-containing building materials (dry mixtures, tongue-and-groove slabs, etc.)
The main advantage is cheap gypsum - a raw material for building materials with increased consumer characteristics.
R&D has been carried out, samples have been received, and a feasibility study has been developed.
The project goes on topics: waste recycling, nanotechnology, ecology, the program "affordable housing".
Equity participation, 50/50, is discussed.
At the stage until the full return of the invested funds - 90/10 in favor of the investor.
Production profitability - 136%

14.08.2017 Moscow region 280 000 000

An investment project for the development of an enterprise for the processing of gypsum stone and the production of gypsum board, GWP, building mixtures in the Altai Territory.

Project for the development of an enterprise for the processing of gypsum stone and production:

• drywall,
• building mixtures.

1. There are no similar enterprises in this region;
2. The region has significant reserves of raw materials;
3. Environmentally friendly parameters of raw materials;
4. Transport accessibility;
5. Affordable cost;
6. Quality indicator is not lower than analogs;
7. Optimal implementation schemes.

• Western Siberia,
• Neighboring regions of the Russian Federation,
• Kazakhstan.

15.02.2017 Altai region 2 000 000 000

Investment project for the creation of a line for the production of steel profiles for the installation of drywall in the Altai Territory.

Creation of a line for the production of steel profiles for the installation of drywall in the Altai Territory.

Closing a need:

• construction companies,
• private developers,
• individual construction crews,
• retail construction networks.

Competitive advantages of the project:
There is no similar production in the region, at present all the product is imported.

Geography of sales of products / construction projects:

• Siberian Federal District,
• Kazakhstan.

Brief information about the state of the industry at the regional level:
Annual growth is 15-20%.

The share of the economically active population in the region:
58%.

06.11.2015 Altai Republic 3 000 000

Modernization of equipment at the Khabezsky gypsum plant and expanding the range of products based on gypsum binder in the Khabezsky region of the Karachay-Cherkess Republic.

Modernization of gypsum plant equipment.

Objectives of the project:
Completion of technical re-equipment of the Khabez gypsum plant, increase in the output of existing and start of production of new products.

Acquisition:

• gypsum calcination lines
• gypsum board production lines with a production capacity of 20 million sq. m / year,
• lines for the production of GWP. with a production capacity of 450 sq.m. / year,
• lines for the production of dry building mixtures - 90 thousand tons / year.

What needs of potential consumers does the project satisfy:
providing construction organizations, the population of the KChR and the North Caucasus Federal District as a whole with a new type of building materials at an affordable price

Competitive advantages of the project:

• creation of about 140 jobs, as well as stimulating the emergence of additional jobs in related industries
• production of high-quality innovative products, the popularity of which is growing in the world,
• there is no similar production in the KChR
• all necessary licenses were obtained, design and estimate documentation was completed;
• the ownership of land was purchased;
• availability of a raw material base;
• selected and negotiated with suppliers of equipment and vehicles;
• availability of labor potential;
• negotiations are underway with a credit institution

Introduction

Basic concepts of mineral binders, their significance for the national economy. There are many different types of binders. However, only some of them are used in construction. They are called building binders.

Building mineral binders are powdered materials, which, after mixing with water, form a mass that gradually hardens and turns into a stone-like state. Building materials are divided into two groups: inorganic (mineral), the most important of which are Portland cement and its varieties, gypsum lime and others, and organic, of which the products of the distillation of oil and coal (bitumen, tar), called black binders, are most used.

Building materials have played a large role in the development of culture and technology. Without them, the construction of buildings and structures would have been impossible. One of the first places among building materials is occupied by binders, which are the basis of modern construction.

The production of binders is a complex of chemical and physical-mechanical effects on the raw materials, carried out in a certain sequence.

Astringents are the backbone of modern construction. They are widely used for the manufacture of plaster and masonry mortars, as well as a variety of concretes (heavy and light). All possible building products and structures are made of concrete, including steel reinforcement (reinforced concrete, reinforced silicate, etc.). Individual parts of buildings and entire structures (bridges, dams, etc.) are erected from concrete on binders.

Approximately 4-3 thousand years BC. astringents appeared, obtained artificially - by firing. The first of them was stucco, obtained by firing gypsum stone at a relatively low temperature of 413-463K.

Gypsum binders are powdered materials consisting of semi-aqueous gypsum and usually obtained by heat treatment of dihydrous gypsum in the range of 105-200 0 C. Gypsum, according to the conditions of heat treatment, setting and hardening speed, is divided into 2 groups: low-fired and high-fired.

Low-fired binders quickly set and harden; They consist mainly of semi-aqueous gypsum obtained by heat treatment of gypsum stone at t 383-453 0 C. These include building (alabaster) molding high-strength (technical) and medical gypsum, as well as gypsum binders from gypsum-containing materials.

High firing slowly set and harden, consist mainly of anhydrous calcium sulfate, obtained by firing at a temperature of 873-1173K. These include anhydrite binder (anhydrite cement), high-fired gypsum (estrich gypsum) and finishing gypsum cement.

By variety. Objects use one of the first places among binders is gypsum. The use of gypsum materials and products helps to save fuel, cement, reduce labor intensity and construction costs. Gypsum is used as a plastering material, for making ornamental decorations and for decorating buildings. In addition, they are used for the manufacture of gypsum concrete rolling partitions and partition plates.

Unfortunately, the production and use of gypsum products in the construction industry of Kyrgyzstan, in comparison with other countries - far and near abroad, is still in its infancy. In Kyrgyzstan, there is a colossal stock of gypsum stone, but they are almost never used in the building materials industry.

Nomenclature

Gypsum binders (GOST 125-79, STSEV 826-77) are obtained by heat treatment of gypsum raw materials to calcium sulfate hemihydrate. They are used for the manufacture of building products of all types and in the production of construction work.

The brand of gypsum binders from G-2 to G-25 is characterized by the compressive strength of the corresponding grades varying within 2… .25 MPa, and at bending 1.2… .8 MPA.

Depending on the setting time, there are fast-hardening binders (A), normal-hardening (B), with the beginning of setting, respectively, no earlier than 2, 6 and 20 minutes and the end no later than 15, 30.

Depending on the degree of grinding, binders are distinguished for coarse (I), medium (II), fine grinding (III) with a maximum residue on a sieve with a mesh size of 02 mm, respectively, no more than 23.14 and 2%.

Gypsum grades G-2… .G-7, of all hardening periods and degrees of grinding are intended for the manufacture of gypsum building products of all types.

Justification of the production method

Firing gypsum in rotary kilns... Rotary kilns used for burning gypsum are an inclined metal drum along which previously crushed gypsum stone moves slowly. Gypsum is fired with flue gases generated during the combustion of various types of fuel (solid, liquid and gaseous) in furnaces at furnaces.

The most widespread are ovens such as drying drums, in which heating is produced by gases passing through the drum. Furnaces with heating by flue gases of the outer surface of the drum can also be used, as well as furnaces in which flue gases are first washed outside the drum and then pass through its inner cavity. In furnaces with direct heating of the material, a mixing chamber is often placed between the firebox and the working cavity of the drum, in which the temperature of the gases leaving the firebox is lowered by mixing with cold air. The speed of movement of gases in the drum is 1-2m / s, at a higher speed, the entrainment of small particles of gypsum increases significantly. Dedusting devices and a smoke exhauster are installed behind the drum.

That part of the drum, in which dehydration occurs most intensively, is sometimes expanded, as a result of which the movement of both the gas flow and the material with high mobility slows down in this zone of the furnace, especially during the "boiling" period. To slow down the aperture. In the working cavity of the drum, a device for moving gypsum during firing is reinforced, which ensures its uniform dehydration. Moving the device also creates a large contact surface of the fired material with the hot gas stream. The absence of mixing devices worsens the conditions for dehydration.

Firing gypsum in rotary kilns can be carried out using the co-current and counter-current method. In the first method, gypsum stone is exposed to high temperatures at the beginning of firing, and in the second, at the end of firing. The temperature of the gases entering the furnace with a forward flow is 1223-1273K, and with a counterflow -1023-1073K. the temperature of gases leaving the furnace with a forward flow is 443-493K, and with a counterflow -373-383K. With the direct-flow method, the material is not burnt out, but the fuel consumption increases, since in the zone of maximum temperatures only preparatory processes take place - heating and drying of the material, while dehydration occurs in the zone of lower temperatures. It is preferable to use rotary kilns operating on the counterflow principle.

It is advisable to direct the hot material coming out of the oven into the simmering hopper or subject it to hot grinding. The latter is especially effective in improving the properties of gypsum, since the leveling of the mineral composition of the final product occurs faster due to the dehydration of the remaining dihydrate and the binding of the released water with soluble anhydrite.

To obtain high quality stucco in rotating drums, crushed gypsum stone with a uniform particle size should be fired. Otherwise, an uneven firing of the material occurs: small grains are burned up to the formation of insoluble anhydrite, and the inner part of large grains remains in the form of undecomposed dihydrate. In practical conditions, material with a grain size of up to 0.035 m is loaded into the furnace, and grains less than 0.01 m in size are sifted out. Dust particles are formed in kilns due to abrasion of material during movement during dehydration, especially when firing softer rocks of gypsum stone. These particles are carried away by the flow of gases and pass through the furnace faster, but some of them still have time to completely dehydrate. It is desirable to burn separately the fractions 0.01-0.2 and 0.02-0.035 m. The sifted fraction with a grain size of less than 0.01 m can be used after additional grinding for the production of stucco and digesters or for the production of raw gypsum used for gypsum in alkaline soils. The length of the rotary kilns used for firing gypsum is 8-14 m, the diameter is 1.6 and 2.2 m; their productivity is respectively 5-15t / h; the angle of inclination of the drums is 3-5 0; number of revolutions 2-5 rpm; equivalent fuel consumption 45-60kg per 1 ton of finished product.

Rotary kilns are continuously operating units, resulting in a compact technological scheme. In rotary kilns, crushed gypsum stone of a larger size is fired than in digesters, where it is less well mixed. Nevertheless, in rotary kilns with careful preparation of the material, correctly selected optimal conditions for firing and subsequent grinding of the fired product, it is practically possible to obtain high quality stucco. In fig. 1 shows a technological scheme for the production of stucco with roasting in rotary kilns.

Combined grinding and firing of plaster. Double heat treatment (drying and cooking), even with a combination of drying and grinding, complicates the production process. In the mill, along with grinding and drying, gypsum is dehydrated to some extent. However, the content of hydrated water is still high, as a result of which it is necessary to cook the gypsum in the digester to completely convert it into a hemihydrate. Known schemes for the production of stucco, in which the final dehydration of gypsum to hemihydrate is carried out in the grinding apparatus itself. In this case, the temperature of the flue gases entering the mill should be higher, 873-1073K, than simply when drying and grinding together. The temperature of the gases leaving the installation is 382-423K. equivalent fuel consumption 40-50 kg per 1 ton of plaster. Firing systems for grinding during grinding are compact.

Technological schemes of production with combined grinding and firing differ from each other mainly by grinding devices (mine, ball, aerobic mills), as well as by the fact that in some cases the mills operate with a single use of the heat carrier, and in others, with the return of part of the gases to the mill. after dust collectors. The use of gas recirculation increases energy consumption, but reduces fuel consumption.

In an installation for combined grinding and firing (where firing essentially occurs in a suspended state), due to the elevated temperature and rapid firing, large particles of soluble anhydrite appear in fine fractions and surface layers, while gypsum dihydrate remains undehydrated in the central layers of these particles. The final product sets quickly, which requires the introduction of retarders.

Characteristics of raw materials

The raw material for the production of gypsum binders is natural anhydrite (CaSO 4), mainly natural gypsum (CaSO 2 * 2H 2 O), as well as gypsum-containing waste from the chemical industry.

Natural gypsum (gypsum stone) is of sedimentary origin. The composition of chemically pure dihydrate gypsum: 32.56% CaO, 46.51% SO 3 and 20.93% H 2 O. It is a white mineral, usually containing a certain amount of clay and limestone impurities. Gypsum dihydrate is a soft mineral with a Mohs hardness equal to. The density is 2200-2400kg / m 3.

Impurities of limestone are ballast in the production of stucco, since the latter is fired at temperatures below the dissociation temperature of calcium carbonate. The moisture content of the gypsum stone is 3-5% or more.

Natural anhydrite is a rock of sedimentary origin, consisting of CaSO 4. Under the action of groundwater rocks, anhydrite slowly hydrates and turns into gypsum dihydrate, therefore it usually contains 5-10% or more of gypsum dihydrate.

Anhydrite rock is denser and stronger than gypsum dihydrate. Its true density is 2.9-3.1 g / cm 3. pure white anhydrite, but depending on the content of impurities in it, it has different shades.

Waste from chemical industries is an additional source of raw materials for the production of gypsum binders and is rationally used as by-products of the chemical industry - phosphogypsum, borogypsum, fluorogypsum, etc.

Kyrgyzstan is rich in deposits of a wide variety of building materials. Among them there are deposits of gypsum stones such as Ak-Belekskoe, Jergalanskoe, Karavanskoe, Boomskoe.

Let's take the Boomskoye (Sulu-Terekskoye) gypsum deposit - this area is located 4 km north of the village. Red Bridge in the Chuy region. Investigated by the parties of KSU in 1954. preliminary studied by the Geological Institute of the Academy of Sciences of the Kyrgyz Republic 1984.

The gypsum-bearing horizon is confined to the lower Tertiary red-colored sediment. The total length is 1100m, the capacity is 40-50m. Northwest dip at an angle of 25-40 0. gypsum in clays is present in the form of a cementing admixture, thin (5-10 cm) veins, lenses and individual nodules 15-20 cm in size. The total content of gypsum in the rock does not exceed 30-40%. In the upper part of the horizon, there is a layer of white and reddish gypsum contaminated with clay material. The seam was traced for 150m at a thickness of 3-5m.

Bulk density of unbaked gypsum 1.27, calcined gypsum 1.165. normal density 75%. Setting time: start in 6 minutes, end in 8 minutes. flow time 5min. tensile strength at the age of 7 days - 3.85 kg / cm 2. gypsum-bearing clays are unsuitable as raw materials for construction purposes and for obtaining fertilizers. Separate gypsum-rich sections of such clays can be used to produce low-grade gypsum and gange. In the seam of the sample sample, the content of CaSO 4 * 2H 2 O reaches 91%.

Technological calculation

The number of working days per year is calculated using the formula:

C p = 365- (B + P) days

where C p is the number of working days in a year;

365 days a year;

B-the number of days off with a five-day work week;

P - holidays.

C p = 365- (B + P) = 251 days

The estimated fund of operating time of technological equipment in hours, on the basis of which the production capacity of the enterprise as a whole and of individual lines of installations is calculated, is determined by the formula:

For the crushing department: B p = 251 * 2 * 8 * 0.92 = 3694.72

For firing: B p = 365 * 3 * 8 * 0.92 = 8059.2

For grinding: B p = 365 * 3 * 8 * 0.92 = 8059.2

For a warehouse: B p = 365 * 3 * 8 * 0.92 = 8059.2

Workshop or factory operating mode

To obtain 1 ton of plaster of paris, you will need gypsum stone:

Taking into account mineral impurities, moisture and technological losses, the consumption of stone will be:

A = 1.18 * 100 / (100-4) * (100-2) = 1.25t

where (100-W) is a coefficient that takes into account the moisture content of the stone;

(100-p) - coefficient taking into account technological losses.

Annual consumption of raw materials (gypsum stone)

P s = P g * A, t / year

Where P s is the annual consumption of raw materials (gypsum stone);

A-consumption of raw materials, taking into account impurities, moisture and technical losses;

П г - annual productivity of the plant for finished products (on assignment).

P s = 100000 * 1.25 = 125000 t / year

Daily consumption of raw materials (gypsum stone):

P year = 125000 t / year

P days = 125000/365 = 34246.6 t / day

P cm = 34246.6 / 3 = 114.15 t / shift

P hour. firing = 125000/8760 = 14.26 t / h

Material balance

Performance

Crushing room capacity:

P g.d. = 125000 t / year

P days dr. = 125000 / С р = 125000/251 = 498 t / day

P see others = P days / 2 = 498/2 = 249 t / shift

P hour = P g / B p = 125000/4016 = 31.12 t / hour

Firing shop productivity:

P g = 100,000 t / g

P day = 100000 / C p = 100000/365 = 273.9 t / day

P cm = P day / 3 = 273.9 / 3 = 91.3 t / shift

P hour = P g / B p = 100000/8760 = 11.41 t / hour

Grinding performance:

P g = 100,000 t / year

P day = P g / 365 = 273.9 t / day

P cm = P day / 3 = 91.3 t / cm

P hour = P g / 8760 = 100000/8760 = 11.41 t / hour

Workshop or plant productivity

Calculation and selection of equipment

Raw material warehouses

Warehouses for lumpy raw materials are constructed and operated in accordance with storage standards, as well as with the standards of technological and construction design of industrial enterprises.

The warehouse is calculated in the following sequence:

1. When choosing a type of warehouse, it is necessary to link the size of the warehouse and its location with the general plan of the plant.

2. The dimensions of the warehouse depend on its type and shape of the stack, as well as the mechanization scheme. The area and capacity of the warehouse are determined by the following formulas:

Where V n is the required storage capacity (in m 3) for a given material;

H n - the maximum stack height is approximately 8-12 m of the stack, taking into account the selected mechanization, with schemes with mechanisms with a grab:

F = 1945 / 0.87 * 11 = 203.23m 2 = 12 x18m,

V n = 100000 * 1.25 * 7/365 * 0.9 * 1.38 = 1930m 3

Bulk material silos

A bunker is a self-unloading container designed for receiving and storing bulk material (limestone, gypsum, active mineral additives, slag, etc.). The depth of the vertical part of the bunker should not exceed its maximum size in terms of more than one and a half times. The lower part of the hopper is made in the form of a funnel, which can be square, round or rectangular. The hopper filling factor is the ratio of the useful capacity V to the geometric V 0 and is expressed by the formula, usually.

The bunkers are designed for storage, crushing and grinding of raw materials for 2-5 hours of continuous operation of the unit. The hopper outlet should be 4-5 times the maximum size of the material piece. The minimum size of the hopper outlet is 800mm.

The calculation of the capacity of the storage bin for raw materials can be done using the following formula:

where P is the hourly productivity of the unit (crushers, ball mills, dryers and furnaces);

n is the maximum storage time of the material in the bin (2-5 hours);

The bin fill factor is usually 0.9;

Bulk material weight, kg / m 3.

For jaw crusher

For hammer crusher

For oven

For the mill

Silo warehouses for storing powdered materials

V c = A c * C n / 365 ** K 3,

where A c is the gypsum production capacity of the plant, t / year;

C n - the number of days of the standard stock (10-15 weeks);

Average volume of the weight of gypsum loaded into silos (1.2-1.45);

K 3 - the filling factor of the silos based on the lack of sleep 2m to the upper edge, usually 0.9.

V c = 100000 * 13/365 * 1.45 * 0.9 = 2729.23

As a result, we accept 2pcs. silo F-8, height - 25m.

Equipment list

Description of the technological scheme

Technological schemes. The technological process in workshops with rotary kilns can be expressed in the following abbreviated scheme: crushing, roasting, grinding.

Below is a description of the technological process for the production of stucco using two rotary kilns.

Gypsum stone delivered by a car is unloaded into a receiving hopper, from which it is sent to a jaw crusher by an apron feeder. Gypsum crushed stone from the jaw crusher is conveyed to a hopper located above the hammer crusher. When processing gypsum stone, which does not require crushing in a jaw crusher, it is possible to feed it into the hopper, bypassing the jaw crusher.

The hammer crusher is fed by a belt feeder, the crushing product is fed by an elevator to an inertial screen, which is divided into fractions 0-2 and 2-25 mm. Fraction 0-2mm is used as a gypsum fertilizer, and in the furnace and partially on the technological line No. 2.

Two rotary kilns operating in direct flow are fed uniformly with crushed stone by means of disc feeders. The residence time of the material in the oven is 45-50 min. The combustion products of natural gas, diluted with air to 900-1100 0 C, enter the furnace, which come out of the furnace, having a temperature of 170-180 0 C.

A cyclone and an electrostatic precipitator are installed to remove dust from gases. The draft in the firebox - oven - cyclone - electrostatic precipitator system is created by a smoke exhauster.

The fired material is fed into containers above two - chamber ball mills, which are fed by disc feeders. The finished binder is transported to the warehouse by pneumatic transport using pumps.

Control of production and quality of products

Control over the production of gypsum binders is divided into operational and technological.

Operational control is ensured by the established technological standards, a given level of quality of finished products in individual production areas and established operating modes of equipment. This control is carried out mainly by service personnel.

When firing gypsum, the parameters of the mode and the operation of the equipment are monitored. The parameters of the furnaces are monitored by a gypsum roaster according to the indications of instrumentation. When firing lumpy gypsum, the firing is checked visually by the fracture of the fired crushed stone. The final conclusion about the quality of firing is given by the laboratory.

Technological control has the goal of managing production as a whole, ensuring a given level of product quality, as well as improving production technology and is carried out by the factory laboratory. She also controls the properties of gypsum binders; setting times, grades, degree of grinding, normal density, volumetric expansion, content of impurities and hydrated water.

Depending on the quality, the stucco is divided into three grades. It must meet the following requirements:

fineness of grinding (residue on a sieve with mesh No. 02),% by weight is no more: for the first grade - 15, for the second - 20, for the third -30.

the ultimate compressive strength of samples aged 1.5 g is equal to, kg / cm 2: for the first grade-53, for the second-45, for the third-35

the beginning of setting is at least 4, and the end is at least 6 and not more than 30 minutes after the beginning of the gypsum dough hardening.

the time from the beginning of the gypsum test hardening to the end of crystallization should be at least 12 minutes.

The addition of 5% lime to gypsum improves the basic properties of the hardened gypsum (strength, water - frost resistance, fluidity under load) and accelerates drying. As additives, you can use a mixture of dextrin and soluble glass, while gypsum acquires increased water resistance and strength.

Plaster of paris is shipped without containers, in bulk and transported in closed vehicles. During transport, it must be protected from moisture and contamination.

Gypsum should be stored in closed dry warehouses (in bins) with solid flooring and protected from moisture (steam, groundwater and atmospheric precipitation), as well as from dust pollution. The floor in warehouses must be raised at least 30 cm above ground level. Stack height 2m.

Industrial automation and safety in gypsum plants

Modern plaster industry enterprises are generally highly mechanized. The widespread use at factories of conveyors, elevators, augers, grinding and other mechanisms that form connected transport systems of considerable length, makes it necessary to observe a certain sequence of switching on and off of individual mechanisms. This requires the automation of production.

During the design, construction and operation of new and reconstruction of existing enterprises for the production of plaster of paris and other binders, one should be guided by the "Sanitary Standards of Industrial Enterprises" and "Safety Rules in the Plaster Industry".

In the production of gypsum and products from it, unfavorable working conditions are most often caused by an increased structure of dust and moisture in the air of premises, insufficient thermal insulation of furnaces, digesters, drying drums, as well as knocking out flue gases into the room, which can lead to burns and poisoning, unreliable fencing of rotating parts of individual devices and mechanisms, stairs, pits, etc.

To combat dust, it is necessary to enclose all technological and transport equipment in which dust is formed in hermetically sealed solid metal casings with tightly closed inspection and repair hatches, doors and other openings. In places where dust and gases are generated, in addition to general ventilation, local aspiration should be arranged to remove dust and gases directly from the points of their formation. Steam pipes from digesters, drying drums and other units must be connected to a dust collection system to collect dust. Flue gases and air should be cleaned in the most efficient dust-collecting devices, in particular in electrostatic precipitators, which guarantee at least 98% dust removal from gases.

General and local ventilation systems must ensure the proper sanitary and hygienic condition of industrial premises. The permissible concentration of dust and toxic gases in the indoor air should not exceed (mg / m 3)

To improve the sanitary conditions of work at gypsum and other factories of binders, the replacement of mechanical transport with pneumatic ones, the use of electrostatic precipitators for cleaning dusty air and sealing of dusty equipment are of particular importance.

All rotating parts of drives and other machinery must be properly guarded. The factories should have a sound or light alarm warning the maintenance personnel about the start-up of this or that equipment, as well as about malfunctions in certain technological stages that can cause accidents. All conductive parts must be insulated, and metal parts of mechanisms and devices must be grounded in case of damage to the insulation.

The creation of safe working conditions should also be ensured by further improvement of technology, full mechanization and automation of all production processes.

At factories of binders, including gypsum ones, they use: automatic control of technological parameters; centralized remote control of electric drives of the main and auxiliary mechanisms, as well as switching and regulating devices; automatic control of the operation of individual technological units and lines.

At present, in the manufacture of semi-aqueous gypsum, automatic control of the operation of crushers, filling of bunkers with gypsum crushed stone, mine and other mills for grinding two-water gypsum, calcining gypsum in a digester or a rotary kiln, etc. is carried out.

The scheme for automating the operation of a periodically operating digester provides for the automatic shutdown of screw conveyors for supplying gypsum two-water powder to the boiler at the moment when the set upper level of the material is reached in it. This is ensured by the level indicator of the respective relays acting on the supply of current to the electric motors. Subsequently, when the set temperature is reached, the corresponding electric motors are switched on, the outlet gates of the digester are opened, and the product is discharged into the holding bin. After the plaster is released, the lower level indicator turns on the corresponding one.

Drywall

Gypsum plasterboard is a building and finishing material used for wall cladding, interior partitions, suspended ceilings, fire retardant structures, as well as for the manufacture of decorative and sound-absorbing products.

The end edges of the sheets have a rectangular shape and when making a seam, they must be chamfered (approximately 1/3 of the sheet thickness).

The conventional designation of gypsum plasterboard sheets consists of: letter designation of the type of sheet; sheet group designations; designations of the type of longitudinal edges of the sheet; numbers indicating the nominal length, width and thickness of the sheet in millimeters; designation of the standard.

An example of a conventional designation of a conventional gypsum plasterboard sheet of group A, with thinned edges, 2500 mm long, 1200 mm wide and 12.5 mm thick: GKL-A-UK-2500 × 1200 × 12.5 GOST 6266-97.

Strength

Evaluation of the strength of gypsum plasterboard in bending is carried out according to the results of tests of several samples (3 longitudinal and 3 transverse) from the batch. The tests are carried out on samples 400 mm wide, mounted on supports with a span of L = 40 × S, where S is the sheet thickness. The test results (arithmetic mean) must correspond to the data in the table.

The strength of the sheets produced exceeds the minimum permissible values. For example, for sheets with a thickness of 12.5 mm, the breaking load for longitudinal specimens is sometimes 730 N.

mineral binder firing

The weight of an ordinary sheet with dimensions of 2500 × 1200 × 12.5 mm (3 m²) is about 29 kg.

Fire-technical characteristics

Plasterboard sheets GKL, GKLV, GKLO, GKLVO belong to the flammability group G1 (according to GOST 30244), to the flammability group B3 (according to GOST 30402), to the group of smoke-generating ability D1 (according to GOST 12.1.044), to the toxicity group T1 (according to GOST 12.1.044).

Transportation and storage.

Plasterboard is transported by all types of transport in accordance with the rules for the carriage of goods in force for this type of transport, in packaged form. A package is formed from sheets of the same group, type and size, laid flat on pallets or spacers made of wood or plasterboard strips and other materials, usually with steel or synthetic tape strapping and wrapped in shrink polyethylene film.

Transportation and storage of drywall requires compliance with some rules:

· Dimensions of a transport package (with a pallet or gaskets) should not exceed 4100 × 1300 × 800 mm, weight - not more than 3000 kg;

· A stack formed from packages, during storage, should not be higher than 3.5 meters;

· When transporting transport packages in open rail and road vehicles, the packages must be protected from moisture;

· During loading and unloading, transport and storage and other works, strikes on sheets are not allowed;

GKL should be stored in a closed dry room with a dry or normal humidity regime, separately by type and size.

Production and composition.

The technological process for the manufacture of gypsum plasterboard includes the formation on a conveyor of a continuous flat strip with a section of a given shape (required thickness and type of side edges), 1200 mm wide, consisting of two layers of special cardboard with an interlayer of gypsum dough with reinforcing additives, while the side edges of the strip are rolled with edges cardboard (face layer). After the gypsum has "set", the strip is cut into separate sheets, as well as drying, marking, stacking and packaging of finished products.

For the formation of the core, gypsum is used, which has exceptional physical and technical properties as a building material. Gypsum-based materials have the ability to breathe, that is, to absorb excess moisture and release it into the environment when there is a lack. Gypsum is a non-combustible, fire-resistant material, it does not contain toxic components and has an acidity similar to that of human skin, its production and use does not have a harmful effect on the environment. To achieve the necessary indicators of the gypsum core, characterizing its strength, density, etc., special components are added to it that increase its operational properties.

Another important component of drywall is facing cardboard, the adhesion of which to the core is ensured through the use of adhesive additives. Cardboard plays the role of a reinforcing shell, and at the same time it is an excellent basis for applying any finishing material (plaster, wallpaper, paint, ceramic tiles, etc.). In terms of its physical and hygienic properties, cardboard is ideal for living quarters.

Description of the material.

Drywall is a composite material in the form of sheets, the length of which is 2.5-4.8 m, the width is 1.2-1.3 m and the thickness is 8-24 mm. Gypsum board is made from gypsum plaster, and the gypsum core is pasted over on both sides with special cardboard. Of the total mass of the sheet, approximately 93% is gypsum dihydrate, 6% is for cardboard, and the last 1% of the mass is formed by moisture, starch and organic surfactant. In terms of its physical and hygienic properties, drywall is ideal for living quarters. It is environmentally friendly, does not contain toxic components and does not have a harmful effect on the environment, which is confirmed by hygienic and radiation certificates. Drywall is an energy-saving material that also has good soundproofing properties. Non-flammable and fire retardant. In addition, drywall "breathes", that is, it absorbs moisture in case of its excess in the air and gives it back if the air is too dry. This is a very important, one might say invaluable quality of the material used indoors. Plus - it has an acidity similar to that of human skin. The last two properties allow drywall to regulate the microclimate of the premises in a natural way and greatly contribute to the creation of a harmonious atmosphere. Drywall is lightweight. When using it, inconvenient “wet” processes that create uncomfortable conditions at the facility are excluded, and labor productivity is significantly increased.

Gypsum concrete panels for partitions

Technical requirements.

1.1 Panels should be manufactured in accordance with the requirements of this standard according to working drawings and technological documentation, approved in the prescribed manner.

1.2 Main parameters and dimensions

1.3 Panels are subdivided, depending on the design solution, into types:

1.4 PG-without openings;

1.5 GWP - with premiums;

1.6 PGV- with cutouts.

1.7 The shape and dimensions of the panels must correspond to those indicated in the working drawings.

1.8 The panels must have openings for the passage of utilities, embedded pipes, channels, grooves or grooves for hidden wiring, sockets and embedded cylinders for junction boxes, switches and sockets, if this is provided for by the project of a particular building.

1.9 Symbols of panels - according to GOST 23009. the panel brand consists of alphanumeric groups separated by hyphens.

Bibliography

1. Yu.M. Butt, M.M. Sychev, V.V. Timashev "Chemical technology of binders". - Moscow Higher School of 1980

2. A.V. Volzhensky, A.V. Ferronskaya "Gypsum binders and products". - Moscow 1974

3. A.V. Volzhensky "Mineral binders". - Moscow 1986

4. M. Ya. Sapozhnikov, N.E. Drozdov Handbook of equipment for inputs of building materials. - Moscow 1970

Course project
protected with a rating of _________
Project Manager
_______ E. Yu. Ivanova

Explanatory note to the course project
in the discipline "Astringents" on the topic
"Workshop for the production of plaster of paris with simultaneous firing and grinding of raw materials"
Completed:
student P. L. Smirnova

Supervisor
E. Yu. Ivanova

Perm 2009

Content
Introduction 2
1 Justification of the feasibility of construction of the projected production. Range of products. 3
2 Technological part 4
2.1 Calculation and justification of the capacity and mode of the enterprise 4
2.2 Characteristics of raw materials. Material balance calculation 5
2.3 The choice of the technological scheme of production 6
2.4 Technical and economic indicators 13
2.5 Calculation of technical and economic indicators 14
2.6 Control of production and quality of finished products 15
2.7 Measures for labor protection and environmental protection of production 17
References 21

Introduction

Justification of the feasibility of building the projected production. Range of products.

Technological part

Calculation and justification of the capacity and mode of the enterprise

Characteristics of raw materials. Material balance calculation

Table 1 shows the costs of raw materials at each stage of production:
Table 1 - Consumption of raw materials

Table 2 - Mode of operation of workshops

2.3 Selection of the technological scheme of production

Calculation and selection of the main technological equipment

We determine the capacity of warehouses and silos. Determination of the capacity and size of silos depends on the accepted operating mode of the enterprise and the required standard stocks of raw materials and products.
The volume of the warehouse stock of raw materials is calculated by the formula:

Psut - daily productivity, t;
z - norms of the total stock per day.
Minimum warehouse volume in summer:

Minimum warehouse volume in winter:

Warehouse height, h = 12 m, warehouse area, S = 800 m 2.
The real volume of the warehouse is V = h S = 12 800 = 9600 m 3.
The volume of the silo is calculated by the formula:
, where
Pgod - annual productivity, kg;
SN - the number of standard days of stock (for gypsum - 15-30 days);
kz - silo filling factor (taken equal to 0.9).

We accept 3 silos for storage:
1 - diameter 6 m, height 21.5 m, capacity 500 m 3;
2 - diameter 6 m, height 21.5 m, capacity 500 m 3;
3 - diameter 6 m, height 31.2 m, capacity 750 m 3;
The capacity of the supply hoppers is calculated for the four-hour productivity of the devices in front of which they are installed. The volume of the bunker is determined by the formula:
V bun = P ap? T / (? Us? K nap),
where P ap - equipment productivity, t / h;
T = 4 hours;
? us - bulk density of the material, t / m 3;
K nap = 0.9 - the coefficient of filling the bunker.
Let's calculate the capacity of the supply bins:
- lumpy gypsum stone:
V bun = 8.7? 4 / (1.35? 0.9) = 28.6 m 3.
- before the crushers:
V bun = 27? 4 / (1.35? 0.9) = 88.9 m 3.
- in front of the mill:
V bun = 8.6? 4 / (1.35? 0.9) = 28.3 m 3.

Technical and economic indicators

2.5 Calculation of technical and economic indicators

Number of engineers and employees:
25 * 10/100 = 3 people

Determine the coefficient k c:

Labor intensity is determined by:
, where Gh is the annual number of person-hours; A year is a year. performance

Labor productivity is determined by:
, where kc is the payroll

Control of production and quality of finished products

Occupational health and safety measures

Bibliography

Baldin V.P. Production of gypsum binders. - M .: Higher school, 1988 .-- 167 p.
http://www.diamond-nn.ru/rus/information /? ArticleId = 105
Bulychev G.G. Mixed gypsum. - M .: Higher school, 1952 .-- 231 p.
Ovcharenko G.I. Gypsum binders. - Publisher: AltGTU, 1995 .-- 29 p.
Silenok S.G. Mechanical equipment for enterprises of building materials, products and structures. - M .: Mashinostroenie, 1990 .-- 415 p.
Volzhensky A.V. Mineral binders. - M .: Stroyizdat, 1986 .-- 464 p.
Vikhter Ya.I. Production of gypsum binders. - M .: Stroyizdat, 1974 .-- 336 p.
Gorbovets N.V. Production of gypsum. - M .: Higher school, 1981 .-- 176 p.