RU45731U1 - TECHNOLOGICAL COMPLEX FOR PRODUCING COMPOSITE WATER-COAL FUEL - Google Patents

Abstract

The invention relates to methods for producing liquid fuel based on coal and water - composite water-coal fuel (WUT) and can be used in the fuel industry, energy, housing and communal services and other industries.

The aim of the invention is to increase the efficiency of wet grinding in a vibration mill and improve the quality of the finished fuel.

This goal is achieved in that the equipment for wet grinding of coal is represented by a pyro mill, consisting of two horizontal drums located one above the other and hydraulically interconnected by a nozzle, and the sump is additionally equipped with a mechanical activator consisting of a case with perforated ones having a relative rotational speed disks, the gap between which and the side walls of the housing where D is the upper particle size of the solid particles in the fuel.

Description

The invention relates to methods for producing liquid fuel based on coal and water - composite water-coal fuel (WUT) and can be used in the fuel industry, energy, housing and communal services and other industries.

Known technological complex for the preparation of coal-water fuel from raw coal (see 1. Zaydenvarg V.K., Trubetskoy K.P., Murko V.I., Nekhoroshiy I.Kh. Production and use of water-coal fuel. M. Publishing House of Mountain Academy Sciences, 2001, p.52-56), implemented on a pilot industrial coal pipe Belovo-Novosibirsk. At this complex, equipment for crushing and classification is represented by hammer crushers of large and small crushing, vibrating screens with a 6 mm cell. As a result, pre-crushed to cl. 0-3 (6) mm of coal is sent to storage bins, from which it is dosed by tape feeder-dispensers into horizontal drum, ball and rod mills. At the same time, water and a plasticizer reagent are metered into the mills. The water-coal suspension obtained in mills flows into sumps, from which it is pumped for homogenization (mechanical treatment). Mechanical processing is carried out in homogenizing mixers, which are containers rotating around the vertical axis with agitators located inside them. The finished fuel is sent by pumps to storage tanks (2 pcs.).

The closest solution to the technical nature and the achieved result is a method of preparing water-coal suspensions for combustion (see patent No. 2178454 from 10.27.2000, M. class. With 10 L 1/32). According to

of this method, the production of coal-water fuel is carried out by grinding and classifying coal, feeding classified coal, water and a plasticizer reagent into a vertical vertical multi-chamber vibratory mill with a one or two mass vibrational system with an operating body amplitude of 3-5 mm and an oscillation frequency of 10-30 Hz. The disadvantages of the analogue are:

- the use of energy-intensive two-stage grinding of coal sequentially in ball and then rod mills (the specific energy consumption of only wet grinding is 90-110 kW × h / t);

- low homogenization efficiency due to the use of conventional mixing devices.

The disadvantages of the prototype are:

- extremely low efficiency of wet grinding of coal in a vertical multi-chamber mill (in such a mill it is impossible to “bind-hold” water with the crushed coal, as a result, water with plasticizer reagent, passing through the chambers and intermediate interchamber grills, merges into the receiving sump, and coal remains in the chambers of the mill;

- lack of homogenization obtained after wet grinding of a water-coal suspension;

- the complexity and unreliability of a vibrating vertical mill consisting of 5 chambers.

The tasks solved by the invention are:

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

- improving the efficiency of wet grinding in a vibration mill;

- improving the quality of the finished fuel due to effective homogenization (machining).

The tasks are solved in that the equipment for wet grinding of crushed coal is represented by a vibrating mill, consisting of two horizontal drums located one above the other and hydraulically

interconnected by a pipe, and the sump is additionally equipped with a mechanical activator, consisting of a case with perforated disks having a relative frequency of rotation, the gap between which and the side walls of the case where D is the upper particle size of the solid particles in the fuel.

Indeed, the implementation of wet grinding of crushed coal in the presence of a plasticizer reagent in a vibrating mill, consisting of two horizontal drums located one above the other and hydraulically connected by a pipe, allows the necessary time for contacting the crushed coal, water and plasticizer reagent to ensure effective mixing and grinding coal in the presence of a plasticizing agent. This ensures the achievement of the upper limit of particle grinding (D) by regulating the performance of the mill. The mixture of crushed coal, water and a plasticizing reagent passes one horizontal drum of a vibration mill, filled with crushed medium (mainly rods), then flows into the lower drum, filled mainly with ball crushed loading, where it is crushed to the required size. The result is a high efficiency of wet grinding of coal in the presence of a plasticizer reagent. This achieves a low energy consumption of coal grinding in a horizontal vibratory mill, not exceeding 25 kW h / t.

Getting in the mill water-coal suspension with the required upper size D before machining in a special apparatus provides:

- reliable operation of the apparatus for mechanical processing of the suspension - (homogenizer) by reducing the abrasive wear of its working surfaces due to the absence of large particles of coal and rock in the water-coal

suspension (if necessary, a coarse filter of size D can be installed before machining the suspension);

- further reliable operation of nozzles for spraying and burning water-coal fuel due to the exclusion of clogging by large particles.

The mechanical treatment of a water-coal suspension by hydromechanical action in an apparatus equipped with perforated disks having a relative rotational speed relative to each other by supplying a suspension through the end gap between the apparatus body and disks, the value of which is H≥2D, and the cavities formed in the disks by perforation, provide:

- effective homogenization of a water-coal suspension with obtaining a water-coal fuel, stable with the necessary rheological properties. The suspension is fed through a relatively small end gap between the body and relatively rotating perforated disks (one or two of which can be stationary, or rotate in the opposite direction relative to the others) and the cavities formed in the disks by perforation provide a high intensity of hydromechanical processing in a high gradient slit stream ( which is achieved by a high relative rotational speed of closely spaced disks), and due to the effects of cavitation arising in the suspension during its the passage of disc perforation cavities, where there is a sharp change in the pressure field (rarefaction - compression);

- the necessary reliability of the slurry machining apparatus due to the fact that the size of the end gap between the apparatus body and the disks is H≥2D, where D is the upper size of the coal particles after wet grinding or rough classification and during the suspension flow there is no intensive wear of the working surfaces during direct flow interaction with housing and working surfaces of two relatively rotating discs.

The technological complex for producing composite coal-water fuel consists of the following elements (Fig. 1): a source coal warehouse, a conveyor 1, a crusher 2, a screen 3, an elevator 4, an accumulated hopper for crushed coal 5, a metering feeder 6, a vibratory mill 7, which consists of two horizontal drums 8 located one above the other, hydraulically interconnected by a pipe 9, reagent tanks 10 and process water 11, sump 12 for receiving a water-coal slurry from the mill. The sump is equipped with a device for mechanical processing of the slurry 13. The machine for mechanical processing can be installed outside the sump (not shown in the figure). The finished fuel is stored in the storage tank 14.

The apparatus for machining a water-coal suspension (figure 2) consists of a housing 1 and perforated disks 2, rotating relative to each other. Part of the disks may be stationary, or rotate in the opposite direction, as shown in figure 2. The size of the gap 3 between the rotating disks and the walls of the housing is H, where . Perforations 4 are made in the disks, through which a water-carbon suspension passes.

The technological complex works as follows. Initial coal is conveyed by conveyor 1 to a hammer mill 2, where it is crushed to cl. 0-3 (13) mm. Crushed coal from the receiving hopper 3 by the bucket elevator 4 is sent to the storage hopper 5, from which it is sent to the horizontal vibrating mill 7, consisting of two drums 8, located one above the other and hydraulically interconnected by a pipe 9. with a belt feeder-doser 6. Into the feeding funnel the upper drum of the vibratory mill is simultaneously dosed with water 11 with reagent-plasticizer 10. Passing through the vibrating upper drum with a chopping charge, usually consisting of a set of rod th, crushed coal is mixed with water and a plasticizer reagent and pre-crushed. The resulting mixture flows through the pipe into the lower drum, usually loaded with a ball load or rods whose diameter is less than the diameter of the rods of the upper drum. Passing the second drum and the vibrating grinding charge, the mixture is refined and flows through the discharge pipe from the mill to the sump 12.

Thus, horizontal grinding drums with rods or balls of a vibratory mill provide the necessary time for effective mixing of coal with water and a plasticizing reagent and obtaining the required size (D) of the suspension at the outlet of the mill. At the same time, the indicated time depends on the productivity of the feedstock, the mass fraction of the solid phase and the initial particle size of the material. The presence of a plasticizer reagent during wet grinding ensures its effective use due to the adsorption of surface-active substances (surfactants) on freshly discovered surfaces of coal particles during their destruction. If necessary, the water-carbon suspension is additionally classified (filtered) according to the required upper size D (as a rule, D = 200-500 μm) (not shown in the figure). For classification, a vibrating screen with a cell equal to D. can be used. Top classification product

return to the source of raw materials or to the storage hopper, and the lower product by pump or gravity is sent to the machine for machining.

Entering the apparatus for machining 13 (figure 1), the water-carbon suspension passes through the end gap 3 (figure 2) between the body and the disks and the cavity 5 (figure 2) formed by perforation. In this case, the coal-water suspension is subjected to a powerful hydromechanical effect due to the high gradient flow between the internal surfaces of the housing and the disks and cavitation in the zones formed in the disk perforation cavities) with a sharp change in the pressure field in them (from rarefaction to pressure increase) due to the high relative frequency rotation.

Due to the indicated hydromechanical effect, the water-coal suspension acquires the necessary stability and rheological characteristics.

The size of the gap H≥2D provides the necessary mechanical reliability of the apparatus for machining a water-coal suspension, since it minimizes direct contact of coal particles with the inner surface of the housing and the working surfaces of perforated disks rotating with a high relative frequency. The resulting water-coal fuel is sent to the storage tank 14 (figure 1) and then burned without further processing in the furnaces of the boilers. At the same time, the nozzles used for spraying work reliably without clogging with large particles, the absence of which is ensured by the tuned grinding technology for the upper particle size (D) or by the coarse and fine filters used for classifiers.

Below are examples of the implementation of the complex for producing composite coal-water fuel in a bench demonstration

installation (Novokuznetsk) and an operated industrial installation at the Tyrganskaya mine (Prokopyevsk).

In the conditions of a bench demonstration installation, the technological complex for producing composite coal-water fuel is implemented as follows.

Original coal 0-25 (100) mm is crushed in a hammer mill to cl. 0-3 (13) mm. Crushed coal is poured into the storage hopper, from which it is dosed with a screw feeder-dosing unit into the receiving funnel of the upper horizontal drum of the BMP-60 vibrating mill (photo 1 of the appendix). At the same time, an aqueous solution of a plasticizing agent is sent to the funnel through a flow meter with a control valve. Passing the upper drum, the resulting coal-water suspension through the nozzle enters the lower horizontal drum of the vibratory mill, where it is crushed. In this case, the upper drum of the vibration mill is loaded with rods, and the lower one is loaded with balls. The water-carbon suspension emerging from the lower drum flows into the sump, from which it is pumped to a vibrating screen with a mesh of 0.5 × 0.5 mm. The lower classification product is collected in a container, from which it enters the inlet pipe of the machining apparatus (photo 2 applications). The machining apparatus consists of a housing, inside of which there are two perforated discs, one of which rotates at a speed of 6000 rpm, and the other is stationary. The gap between the case and the discs is 1 mm. The water-coal suspension passed through the apparatus is subjected to a powerful hydrodynamic effect in the gap between the housing and the disks and in the cavity of the disks formed by perforation. As a result, water-coal fuel with the necessary rheological characteristics comes out of the apparatus, ready for long-term storage, pipeline transportation and direct combustion. In the conditions of the demonstration installation, the obtained coal-water fuel is directly burned without additional preparation in a specially equipped combustion chamber (photo 3 of the appendix).

Under the conditions of an operating industrial installation at the Tyrganskaya mine (Prokopiesk), the complex for producing composite coal-water fuel is implemented as follows.

Coal slurry of hydraulic mining with a grain size of 0-0.5 (13) mm is used as a feedstock for the preparation of water-coal fuel; therefore, the unit does not have a preliminary coal crushing unit. Coal slurry from the warehouse is transported by truck to the installation warehouse, where it is fed by a grab onto the grate located above the buried receiving hopper (photo 4 of the appendix). From the hopper, the sludge enters the scraper conveyor, which feeds the sludge into the bucket elevator. The sludge is loaded with an elevator into the storage hopper (photo 5 of the appendix), from which it is fed with a tape feeder-dispenser to the scraper conveyor (photo 6 of the appendix), which transports the sludge into the loading funnel of the top horizontal drum of the VM-400 vibrating mill (photo 7 of the appendix). At the same time, an aqueous solution of a plasticizer reagent is metered into the feed hopper through a flow meter with a control valve. From the upper drum, the water-carbon suspension through the nozzle enters the lower horizontal drum of the vibratory mill, where it is crushed. From the lower drum, the water-carbon suspension merges into a sump. The grinding medium of the upper drum of the vibratory mill is the rods, the lower one is balls. From the sump, the suspension is pumped through a self-cleaning filter to a machining apparatus, the design of which is similar to that used in the demonstration unit. The slot width of the self-cleaning filter is 0.5 mm. From the machining apparatus, the finished water-carbon fuel is discharged into the storage tank.

Thus, the implemented practical implementation of the proposed technological complex confirms the high efficiency of the claimed technical solution.

The results of the demonstration and industrial installations are presented in the table.

Table - The results of the demonstration and industrial installations Parameter Name Numerical value Demo installation Industrial installation Productivity, t / h 0.5 2,5 Initial coal (brand) D, G, SS, etc. SS _w Fineness of initial coal, mm 0-25 (100) 0-0.5 (13) Ash content of coal,% 5-40 15-35 Mass fraction of solid phase,% 58-68 60-68 The particle size in the finished HLW, mm 0-0.25 0-0.25 Effective viscosity at a shear rate of 81 s ^-1 , MPa × s 200-800 400-800 Stability, days, not less 10 thirty

Claims (1)

A technological complex for producing composite coal-water fuel, including equipment for crushing and classification of coal, its accumulation, equipment for wet grinding of crushed coal to a given size with a sump for receiving the crushed product, a dosed water supply system and a plasticizing reagent for wet grinding, an accumulating tank, Technologically interconnected by conveyors and pipelines, characterized in that the equipment for wet grinding of coal is represented by vibromel nitsey consisting of two horizontal drums arranged one above the other and fluidly interconnected pipe and the sump is further equipped with a mechanical activator consisting of a perforated casing having a relative rotation between a frequency drives, the gap between them and the side walls of the housing

where D is the upper particle size of solid particles in the fuel.