RU2637119C2 - Line for producing fine-dispersed coal-water slurry - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention discloses a line for producing a fine-dispersed coal-water slurry that contains a receiving hopper for the coal component of the slurry, connected through a feeder with a shredder, to the inputs of which the water feed and diluent-stabiliser lines are also fed, as well as a device for activating the slurry, the yield of which is bound with a storage capacity intended for storing and dispensing the target product. The line is equipped with the second shredder and a hydrocyclone. As the first shredder, a parabolic vibroimpulse mill is used, and as a device for activating the slurry - a hydrostatic cavitator, the output of the parabolic vibroimpulse mill is connected with the hydrocyclone, the first output of the hydrocyclone is connected to the intermediate vessel, the output of which is connected to the input of the parabolic vibroimpulse mill, and the second - to the second shredder connected by its output to the input of the hydrostatic cavitator.

EFFECT: producing a high quality coal-water slurry.

1 dwg

Description

The invention relates to equipment for producing high-quality water-coal fuel mixtures, which can be used to replace fuel oil from power units or can be used to produce generator gas.

A known production line for producing coal-water fuel, containing containers for a solid component of fuel (coal), for a liquid component of fuel (water) and additives necessary to obtain a coal-water suspension.

The capacity (hopper) for the solid fuel component is connected to the chopper. Tanks for water, additives and the grinder outlet are connected to the mixer, and the mixer outlet is connected to a hydropercussion device, the outlet of which is connected to the reservoir for storing and distributing the obtained water-coal fuel (water-coal suspension).

The output of the hydropercussion device by the bypass line is additionally connected to the mixer.

During the operation of the line, the solid fuel component from the hopper is fed to the chopper, where it is preliminarily ground. The crushed component is loaded into the mixer, where the liquid fuel component (water) and, if necessary, additives are also fed. In the mixer, the components loaded into it are mixed with the formation of a coarse suspension, which is fed to the hydropercussion device. In this device, the fuel components are dispersed, heated and activated until a finely dispersed suspension is formed, which is fed to the reservoir for storage and distribution to consumers. In the event that it is necessary to re-process the resulting finely dispersed suspension, it is sent not to the tank, but recycled by the bypass line to the mixer for re-treatment, after which it is again fed to the hydropercussion device and then to the tank (see RF patent, No. 2185244, class B02C 21/00, 2000).

As a result of the analysis of the implementation of the known line, it should be noted that mixing the crushed solid component and the liquid component of water-carbon fuel and the subsequent preparation of the suspension in the hydropercussion device does not allow to obtain composite fuel of a sufficiently high quality, since the formation of the fuel composition is carried out with insufficient activation of its solid and liquid components That does not allow the fuel mixture to maintain its properties for a long time. The presence in the resulting fuel mixture of mineral ballast inclusions also reduces its quality.

A known technological complex for producing coal-water fuel, consisting of a hammer crusher designed to grind the coal loaded into it, a screen installed at the outlet of the crusher and designed to sort coal of substandard sizes, an elevator designed to load sorted coal from the screen into a crushed coal storage bin. The technological complex is equipped with a metering feeder located at the outlet of the hopper and connected to the inlet of the vibratory mill, as well as tanks for the reagent - plasticizer and process water associated with the inlet of the vibratory mill. The vibration mill consists of two horizontal drums located one above the other, hydraulically connected by a pipe. The technological complex includes an apparatus for the mechanical activation of a suspension - a sump installed at the output of a vibratory mill. The sump output is associated with a storage tank.

During the operation of the complex, coal is conveyed through the conveyor to a hammer mill, where it is crushed to class 0-3. Crushed coal from the receiving hopper by the bucket elevator is sent to the accumulating hopper, from which it is sent to the horizontal vibrating mill by a tape feeder-dispenser. At the same time, water and a plasticizer reagent are dosed into the feeding funnel of the upper drum of the vibratory mill. Passing through a vibrating upper drum with a grinding charge, usually consisting of a set of rods, crushed coal is mixed with water, with 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 crushed and flows through the discharge pipe from the mill to the sump. In the sump, the water-coal suspension is subjected to hydromechanical effects due to the high-gradient flow between the internal surfaces of the casing and the disks, as well as cavitation in the zones formed in the cavity of the perforation of the disks with a sharp change in the pressure field in them (from rarefaction to pressure increase) due to the high relative speed. Due to the indicated hydromechanical effect, the water-coal suspension acquires the necessary stability and rheological characteristics. The presence of a plasticizing reagent during wet grinding ensures its effective use due to the adsorption of surfactants on freshly discovered surfaces of coal particles during their destruction. The obtained coal-water fuel is sent to the storage tank, from which it is supplied to consumers or sent to the boiler furnaces for combustion (see RF patent for utility model No. 45731, class C10L 1/32, 2005) - the closest analogue.

As a result of the analysis of the known solution, it should be noted that the use of successively installed hammer crushers and vibratory mills does not provide guaranteed grinding of the solid phase to the given finely dispersed sizes of its fragments, and use as a device for activating the sump does not provide high-quality mechanochemical activation of the suspension. In addition, the suspension obtained on this line is characterized by a large spread in the ratios of the solid and liquid phases. All this reduces the quality of the resulting suspension, in particular, due to the significant underburning of the components upon receipt of the generator gas from it, low calorific value and low shelf life.

The technical result of the present invention is to develop a line design that provides high-quality water-carbon suspension.

The specified technical result is ensured by the fact that in the line for producing a finely dispersed coal-water suspension containing a receiving hopper for the coal component of the suspension, connected through a feeder to a grinder, to the inlets of which there are also lines for dosed water supply and a thinner-stabilizer, as well as an apparatus for activating the suspension, the output of which is associated with a consumable capacity intended for storage and delivery of the target product, new is that the line is equipped with a second grinder and a hydrocyclone, etc. why, a parabolic vibroimpulse mill was used as the first grinder, and a shock cavitator was used as an apparatus for activating the suspension, the output of the parabolic vibroimpulse mill is connected to a hydrocyclone, the first output of the hydrocyclone is connected to an intermediate tank, the output of which is connected to the input of a parabolic vibroimpulse mill the second chopper, connected by its output to the inlet of the hydraulic shock cavitator.

The information set forth in the application materials is sufficient for the practical implementation of the utility model.

The essence of the claimed invention is illustrated by graphic materials, which show a diagram of a line for producing a finely dispersed coal-water suspension (TWS).

The line for receiving fuel assemblies contains a receiving hopper 1 with a feeder 2 (for example, a lock) for a solid component of a fuel assemblies (for example, brown coal). The output of the feeder 2 is connected with the first input of the grinder 3 of the solid component of the FCS. As a grinder, a standard hammer mill or, most preferably, a parabolic vibratory impulse mill is used. The design of such a mill is standard.

The second input of the grinder 3 is connected to the water supply line (B), and the third - to the supply line of technological additives (C) (as a rule, these are stabilizer thinners). Water and technological additives can be supplied through pipelines from storage tanks (positions are not indicated). Water can also be supplied directly from the water supply system, and technological additives directly from the installation for their receipt (not shown). The fourth input of the grinder 3 is connected to the output of the intermediate tank 4. At the second, third and fourth inputs of the grinder, dispensers are installed 5. The output of the grinder 3 through the first pump (for example, sand) 6 is connected to the hydrocyclone 7.

The first output of the hydrocyclone is connected to the inlet of the intermediate tank 4, and the second to the input of the second grinder 8. The output of the grinder 8 through the second pump (for example, sand) 6 is connected to the first input of the apparatus for activating the obtained suspension — hydraulic shock cavitator 9. The output of the hydraulic shock cavitator can be connected with one or more consumable containers 10 for collecting and dispensing the target product and / or with the dispensing line of the target product - TVUS, in which the pump 12 (for example, screw) is installed. The line issuing the suspension can be a channel connected to the second input of the cavitator hydropercussion 9.

In the communication lines of a hydrocyclone with an intermediate tank, a cavitator with consumable tanks, a cavitator with a suspension line, adjustable gate valves 12 are installed.

The specific constructive implementation of the units and nodes of the line, as well as its transporting systems are known, they do not constitute the subject of patent protection and therefore are not disclosed in the materials of this application. Naturally, for the transportation of components and their mixtures in the process of obtaining fuel assemblies, the installation uses pumps, pipelines and other fittings, the implementation of which is also known.

The line for producing a finely dispersed coal-water suspension operates as follows.

The operation of the line can be carried out both in manual and automatic mode.

In the receiving hopper 1 load pre-crushed to a given particle size coal. A very promising raw material for the production of high-quality fuel-grade composite materials is enriched heat-treated ground brown coal.

From the hopper 1, the feeder 2 feeds coal into the chopper 3 into a chopper - a parabolic vibratory impulse mill. At the same time, water and a technological additive, namely, a diluent and a stabilizer, are fed through the dispensers 5 into the mill 3 along lines B and C. In a parabolic vibrational pulverizer, the solid component is ground and mixed with water and a diluent stabilizer. As a result, a water-coal suspension is obtained at the outlet of the mill 3. The kinetics of wet coal grinding in parabolic vibratory pulse mills is similar to disintegration processes occurring in a drum ball mill, only with a significant reduction in energy costs (up to 10 times) and reduction of wear (20-30 times) of grinding media. The use of a precisely parabolic vibroimpulse mill as a grinder provides ample opportunities for controlling the output parameters of the milled material based on varying the amplitude and frequency of oscillations, the time spent by the milled material in the grinding chamber, etc. This makes it possible to develop flexible, easily customizable wet grinding circuits that provide TVUS with a given particle size distribution. The mechanism of grinding of solid materials implemented in such mills provides a high probability that practically all particles without exception, during their stay in the grinding chamber, will undergo dynamic action from the grinding bodies. Studies show that at the output of the vibroimpulse mill MV-0.05 there is a very small percentage of large particles of coal, the size of which is commensurate with their input sizes. The presence of such particles in the fuel of the FCS is highly undesirable, since their presence increases the mechanical underburning of coal and reduces the efficiency of the use of this fuel, that is, reduces its quality. Stable water-coal suspensions with average particle sizes of crushed coal above 1 μm are obtained in parabolic vibratory pulse mills. The introduction of thinning additives into water-coal suspensions significantly improves their fluidity, which is expressed in a significant decrease (more than 10 times) in consistency. As such, standard additives (USR, in an amount of 1%, LFR, in an amount of 1%) can be used. It also makes it possible to increase the solid phase content in the suspension by 3-5%, while maintaining the yield strength acceptable for the HFCS. To increase the stabilizing characteristics of the suspension, it is possible to add stabilizing components (bentonite, bischofite) in an amount of 0.5-1.0%.

From the mill 3, the water-carbon suspension obtained in it is fed by the first pump 6 to the hydrocyclone 7. Hydrocyclone 7 is a standard unit in which, due to the action of centrifugal forces, coal particles having a mass larger than established by the technological requirements are removed from the suspension obtained in the mill. These particles are sent to an intermediate tank 4, from where they are fed to the mill 3 for regrinding. The hydrocyclone also provides a predetermined ratio of the solid and liquid phases of the suspension (optimal ratio: 60% solid and 40% liquid). The use of a hydrocyclone ensures the supply of a suspension to the hydraulic mill, the solid phase of which is guaranteed to be free of fragments whose sizes exceed those established for grinding in a mill.

The suspension, purified from substandard solid particles and having an optimal ratio of solid and liquid phases, is fed to the second grinder 8, in which the hydraulic mill obtained in the mill 3 and purified in the hydrocyclone 7 of the semi-finished product is carried out. In the grinder 8, the solid phase of the suspension is additionally crushed and qualitatively mixed with water and a diluent stabilizer. As the grinder 8 can be used grinder IGP5.

From the grinder 8, the suspension is fed by a second pump 6 to the cavitator hydropercussion 9, in which finely divided solid grinding of the solid phase and its mechanochemical activation takes place.

In the cavitator, grinding is carried out by means of shock-shearing effects on coal particles, which are broken into fragments with their simultaneous deformation. Deformation causes the appearance of mechanical and thermal stresses, electrostatic fields on these particles and leads to an increase in chemical activity on the outer surface and in the pores of solid particles. An increase in the internal energy of particles due to these phenomena caused by the specifics of their grinding makes up from 10 to 30% of the impact energy. With such grinding in suspension, a large number of highly reactive radical particles are formed.

When processing a water-coal suspension in a hydro-shock cavitator, three phases can be distinguished, which differ in the nature of the change in the physicochemical parameters of the water-coal suspension and in the properties of the dispersed phase:

- cavitation destruction to a size of 100 microns, homogenization and primary dispersion of the dispersed phase (average phase duration 5-10 minutes);

- the main phase of dispersion is the activation of the surface physicochemical properties of the dispersed phase, an increase in the yield of the ultrafine phase and, consequently, an increase in sediment volume, an increase in the structural-mechanical barrier, sedimentation stability of the suspension (average phase duration is 20-30 minutes);

- a decrease in the aggregative and sedimentation stability of the FCS upon reaching a critical value of the degree of dispersion and concentration of the dispersed phase (average phase duration 10-20 min.).

Thus, during cavitation treatment of the suspension, we obtain an activated metastable finely dispersed medium. In addition, cavitational devices have low metal consumption, high performance and low power consumption. At the output of the hydraulic shock cavitator, we obtain the target product - TWCS, which is supplied, depending on the position of the valves 12, into the storage tanks 10 and / or to the screw pump 11, by which the TWCS is sent, for example, to a direct-flow swirl gas generator to produce generator gas.

In the case of long-term storage in storage tanks, TWS can be fed to the second input of the hydraulic shock cavitator 9 for its activation and return to storage tanks 10.

The developed production line for the production of TVUS according to the design principle is linear, which is very convenient for automating the technological process of obtaining TVUS. At the same time, this scheme allows you to flexibly organize the production of high-quality TVUS depending on the initial components. Using the line allows you to get TVUS with the following characteristics:

- high calorie content (up to 6000 kcal / kg);

- low ash content (from 1 to 1.5%);

- satisfactory fluidity with a viscosity index of 144 cSt at t = 30 ° C (for reference, the viscosity of fuel oil at this temperature is 70-98 cSt);

- high stability (retains structure during storage for at least a year and when transported by road to a distance of at least 500 km).

Claims (1)

A line for producing a finely dispersed coal-water slurry, containing a receiving hopper for the coal component of the slurry, connected through a feeder to a grinder, to the inlets of which there are also lines for dosed water supply and a thinner-stabilizer, as well as an apparatus for activating the slurry, the output of which is connected to a consumable container for storage and delivery of the target product, characterized in that the line is equipped with a second grinder and a hydrocyclone, with parabol being used as the first grinder a vibratory impulse mill, and as a device for activating a suspension, a water shock cavitator, the output of a parabolic vibroimpulse mill is connected to a hydrocyclone, the first output of a hydrocyclone is connected to an intermediate tank, the output of which is connected to the input of a parabolic vibroimpulse mill, and the second to a second grinder connected by its output with the entrance of the cavitator hydropercussion.

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