RU57279U1 - TECHNOLOGICAL COMPLEX FOR COAL PROCESSING - Google Patents

Abstract

The invention relates to coal processing technologies by enrichment and combustion. It can be used in the coal industry and energy. It differs in that the complex is additionally equipped with a plant for producing a highly concentrated water-coal slurry, represented by a mechanical mixer with a metered supply of dehydrated coal sludge and industrial water with a plasticizing additive, the discharge pipe of which is equipped with a control sieve with a vibrator, and the receiving tank is made in the form of two successive hydraulically interconnected compartments, in the subsequent of which a submersible activator pump is installed, the discharge pipe of which the pipe is connected to the storage tank, while the furnaces of the boiler units are equipped with vortex chambers for burning the suspension, which is pumped from the storage tank through fine filters to the nozzles, and the size of the filter slots is determined by the ratio where d _with - the diameter of the nozzles of the nozzles.

Description

The invention relates to technologies for processing coal by enriching and burning it. It can be used in the coal industry and energy.

Known methods of processing coal at coal preparation plants (see 1. Handbook of coal preparation. Edited by I. S. Blagov, A. M. Kotkin, L. S. Zarubin. 2 ed. Revised and added M: Nedra 1984, p. 54-70). Existing technological schemes use coal crushing processes, enrichment of large and small classes with the production of concentrate, industrial product and rock. A feature of coal processing plants with a wet enrichment process is the presence of fine-grained coal sludge, which, in closed cycles of the water-sludge scheme, is captured and dehydrated by filter presses. The filtercake obtained with this, as a rule, is mixed with the rock and shipped to the dump, or in small quantities it is added to the industrial product or concentrate, thereby impairing their quality in terms of humidity and ash content.

The closest solution to the technical nature and the achieved result is a method of utilizing fine coal sludge by burning in the form of coal-water slurries, described in the works (see 2. D. Morrison, A. Scaroni, D. Batista. The use of coal sludge for the production of coal-water fuel. XIII International Coal Preparation Congress Brisbane, Australia 4-10 October, 1998, p.643-645.3 Miller BG, Miller SF, Morrison JD, Scaroni AW, 1997, Co-firing coal-water slurry fuel with pulverized coal as a NO ^x reduction strategy, Fourteenth Annual International Pittsburgh Coal Conference, University of Pittsburgh, Taiyuan, PR China, Adobe Systems, CD ROM Paper 23-4). According to this method, thin coal sludge from the sump is delivered to the place of its burning. A low concentration water-coal suspension is being prepared, which is burned in boiler units together with pulverized coal fuel.

The disadvantages of the analogue and prototype are:

- the need to use external dumps for warehousing and storage of thin coal sludge;

- additional costs for the extraction and transportation of sludge to the place of burning;

- low combustion efficiency due to the high humidity of coal sludge;

- insufficient stability of the resulting suspension with high humidity;

- the need to use additional fuel for sustainable combustion of coal-water slurry from coal sludge.

The tasks solved by the invention are:

- elimination of the disadvantages inherent in the analogue or prototype;

- elimination of sludge sedimentation tanks and tailings;

- improving the stability and stability of combustion of a coal-water slurry from thin coal sludge;

- ensuring reliable removal of fly ash from the fuel combustion zone.

The tasks are solved in that the technological complex for coal processing is additionally equipped with a plant for producing a highly concentrated water-coal slurry, represented by a mechanical mixer with a metered supply of coal sludge and industrial water with a plasticizing additive, the discharge pipe of which is equipped with a control sieve with a vibrator, and the receiving tank is made in the form of two successive hydraulically interconnected compartments, the next of which is installed immersed pump activator, discharge conduit which is connected with the storage vessel, wherein the boiler furnace are equipped with swirl chambers for burning the resulting slurry being fed by pumps of the storage tank through the fine filters on the nozzle, wherein the size of the filter slots determined by the relation where d _with - the diameter of the nozzles of the nozzles.

The complex’s equipment with a plant for producing a highly concentrated water-carbon suspension, represented by a mechanical mixer with a dosed supply of dehydrated coal sludge and industrial water with a plasticizing additive, provides:

- the exception of the release of thin coal sludge beyond the complex and thereby the elimination of sludge sedimentation tanks and tailings;

- obtaining a highly concentrated water-coal suspension with minimal energy, and therefore operational costs;

- obtaining a highly concentrated water-coal slurry based on thin coal sludge with predetermined properties in terms of solid phase content, viscosity and lower heat of combustion.

The supply of the discharge pipe of the mixer with a control sieve with a vibrator eliminates the ingress of foreign objects (wood chips, rubber, etc.) and large pieces of coal and rock into the finished water-carbon suspension.

The implementation of the receiving tank in the form of two sequentially installed and hydraulically interconnected compartments, and installation in the subsequent compartment of the submersible activator pump, the discharge pipe of which is connected by a pipe to the storage tank, provides:

- trouble-free operation of the activator pump with a possible breakthrough of the control sieve and metal objects falling into the receiving tank;

- obtaining a highly concentrated water-coal suspension of constant quality with the necessary rheological characteristics and stability.

The equipment of boiler furnaces with vortex chambers for burning the resulting suspension, supplied by pumps from the storage tank through fine filters to nozzles, the size of the slits of which is determined by the ratio where d _{with the} diameter of the nozzles of the nozzles, provides:

- stable and steady burning of water-coal slurry even with high ash content (up to 60-65%) in boiler units without the use of additional fuels;

- reliable removal of fly ash with combustion products from the combustion zone;

- the exception of clogging of nozzle nozzles by large particles of a solid phase and possible clots of fuel.

The coal processing technological complex includes a coal crushing and beneficiation plant, a plant for producing highly concentrated coal-water slurry, and a station with boiler units for generating thermal and (or) electric energy. Installation for highly concentrated water-coal suspension (figure 1) consists of a hopper for dehydrated coal sludge with

a tape dispenser 1, a mechanical mixer 2 with a discharge pipe 3, a container 4 with a stirrer for a plasticizer reagent solution. The discharge pipe is equipped with a control sieve with a vibrator 5. The receiving tank of the mixer 2 is made in the form of two successive hydraulically interconnected compartments 6 and 7. In the subsequent compartment 7, a submersible activator pump 8 is installed, the discharge pipe 9 of which is connected by a pipe to the accumulating tank 10. boilers are equipped with vortex combustion chambers, a diagram of which is presented in figure 2. Burner chambers 13 with nozzles 14 are installed on the combustion chambers. Self-cleaning fine filters 12 are installed on the suction nozzles of the feed pumps 11, the size of the slots of which where d _with - the diameter of the nozzle nozzles. For spraying the suspension, the boiler unit is equipped with a compressor 15.

The technological complex for coal processing works as follows.

In the installation for crushing and beneficiating coal, in addition to concentrate, industrial product and rock, up to 10-20% of coal sludge with a particle size of 0-500 (1000) microns is obtained. Coal sludge after dehydration, as a rule, is sent to the press filters for the preparation of slurry-coal fuel on press filters. When this coal sludge is loaded into a receiving hopper with a dispenser 1 and a belt conveyor is fed into the mixer 2. In this case, the working mixing bodies of the mixer are turned on. At the same time, process water from the existing system and a plasticizer reagent solution from tank 4 are metered into the mixer until the fixed (working) volume of the mixer is filled with the finished suspension. After filling the fixed (working) volume of the mixer, the dosed feed of the starting products into the mixer is stopped, and mixing continues until a homogeneous mixture is obtained. After mixing, the finished suspension fuel is discharged through the discharge pipe 3 to a control sieve with a vibrator 5. Wood chips, rubber, large particles of coal and rock, and other foreign objects are removed into the waste tank, and a highly concentrated water-coal suspension flows by gravity into compartment 6 and then flows into compartment 7, from where the submersible activator pump 8 is pumped through the discharge pipe 9 and the pipeline into the storage tank 10. In the event of an emergency, caused by a breakthrough of the control sieve, p foreign metal objects will be caught in compartment 6. Suspension from the storage tank,

passing fine filters 12, pumps 11 are fed to the nozzles 14 of the burner devices 13 mounted on the vortex combustion chambers with which the furnaces of the boiler units are equipped. Figure 2 shows the scheme of operation of the vortex combustion chamber installed in the furnace of the boiler unit. Due to the tangential supply of atomized fuel to the vortex furnace of the boiler and the vortex movement of droplets of burning fuel and air flows (oxidizer) formed during spraying, reliable and stable operation of the boiler unit is ensured even with a high ash content of the solid phase in suspension fuel. The particles formed during the combustion of fuel droplets, losing their mass, approach the axis of rotation and, reaching the level of the exit window, are carried away into the convective part of the boiler and then into the dust collecting device (not shown in Fig. 2). The cleaned flue gases by the exhaust fan are emitted through the chimney into the atmosphere (not shown in FIG. 2). The thermal energy of the boiler unit is used either for heating or other needs, or water vapor is supplied to turbines that generate electrical energy (not shown in Fig. 2).

The technical feasibility and high economic efficiency of the developed technical proposal is confirmed by the operation of the complex at a demonstration plant in Novokuznetsk and at the industrial complex at the Zarechnaya mine processing plant in Leninsk-Kuznetsk, Kemerovo Region.

An example of the implementation of the developed technical proposal on a demo installation.

The mixer with a working volume of 50 l was loaded:

- technical water - 4.7 kg; - plasticizer reagent - 0.4 kg; - dehydrated coal sludge (flotation waste) with an ash content of 50.4% and a moisture content of 30% - 57.4 kg.

The total mass of loaded materials was 62.5 kg, i.e. when the density of the finished suspension 1250 kg / m ^{3 the} working volume was 50 liters

After stirring for 10 min, a homogeneous, highly concentrated suspension was obtained with a mass fraction of solid phase of 65%, effective viscosity of 550 mPa · s and a lower calorific value of 3100 kcal / kg.

The resulting portion of the suspension was passed through a sieve with a mesh diameter of 3 mm, and then treated with an activator pump (RPA) and fed into a container. From the tank, the suspension was fed through the filter with a hose pump to the nozzle of the burner device,

mounted on a vortex combustion chamber. The size of the filter slit is 1.5 mm with a nozzle diameter of 5 mm, which ensures reliable operation of the nozzle without clogging. The combustion results are presented below:

- pump feed - 50 l / h - pressure of suspension fuel - 0.2 MPa - pressure of compressed atomizing air - 0.2 MPa - temperature in the furnace - 1000 ° C - yield of nitrogen oxides (NO _x ) - 100 mg / m ³ - yield of carbon oxides (CO) - 155 mg / m ³

An example of the implementation of the proposed utility model in an industrial complex.

The Zarechnaya mine processing plant by processing grade G source coal produces concentrate with an ash content of 7.5%, a rock with an ash content of 65%, and coal sludge with a moisture content of 30% and an ash content of 35%.

In the technological complex of the factory, a plant for the preparation of slurry fuel from dehydrated coal sludge was created, consisting of a mixer, a vibrating control sieve, a receiving tank with two compartments, one of which has a submersible activator pump, a storage tank with feed pumps, a fine filter and a boiler with a vortex combustion chamber (photo 1, 2, 3).

Technical characteristics of the technological complex

Suspension Performance - up to 10 t / h Mass fraction of solid phase - up to 65% Effective viscosity - no more than 600 MPa · s Solid Ash - 30-35% Particle size in suspension - 0-500 microns Net calorific value - up to 3200 kcal / kg Installed capacity of the slurry preparation unit - 88 kW Boiler heating capacity - 0.5 Gcal / h Fuel supply to the boiler - up to 350 l / h

The complex works as follows. The dehydrated cake of the press filters with a moisture content of 30-32% is loaded by a forklift into the receiving funnel of the conveyor belt, which is sent to a mixer with a working volume of 1.5 m ³ . Pre-loaded into the mixer:

- technical water - 139 l; - plasticizer reagent - 12 kg.

The amount of sludge loaded into the mixer is 1724 kg, while the working volume (1500 l) is filled with the resulting suspension with a density of 1250 kg / m ³ .

After stirring for 30 minutes, a homogeneous suspension is formed with a mass fraction of solid phase of 65%, which is discharged through a discharge pipe onto a vibrating screen with a 3.5 mm mesh. The separated foreign objects and large pieces of coal and rock are separated into the waste tank, and the suspension enters the first compartment of the receiving tank and flows into the second compartment where the submersible activator pump is installed. With the activator pump, the finished suspension is processed and pumped into a storage tank with a capacity of 5 m ³ . From the storage tank, a highly concentrated suspension is supplied by a hose pump with an adjustable drive through a self-cleaning fine filter to the nozzle of the burner device mounted on the vortex chamber of combustion of the E-1-9 water boiler. The size of the filter slit is 2 mm with a nozzle nozzle diameter of 6 mm.

As a result of the operation of the technological complex, high reliability and economic efficiency of the boiler unit during the combustion of the resulting suspension fuel have been established.

Claims (1)

The technological complex for coal processing, including the installation for its crushing and wet enrichment to obtain concentrate, rock and coal sludge, a station with boiler units for the production of thermal and (or) electric energy, characterized in that the complex is additionally equipped with a plant for producing highly concentrated water-coal suspension, represented by a mechanical mixer with a metered supply of coal sludge and industrial water with a plasticizing additive, the discharge pipe of which is supplied a control sieve with a vibrator, and the receiving tank is made in the form of two successive hydraulically interconnected compartments, the next of which is a submersible activator pump, the discharge pipe of which is connected by a pipe to the storage tank, while the boiler furnaces are equipped with vortex chambers for burning the resulting suspension supplied by pumps from the storage tank through fine filters to the nozzles, and the size of the filter slots is determined by the ratio

where d _with - the diameter of the nozzles of the nozzles.