RU2627865C1 - Production method of synthetic gas from low-calorial brown coals with high-ash and device for its implementation - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: feedstock is subjected to disintegration, drying and gas generation in the field of the cyclonic swirl with the high temperature field applied to the swirling stream, where the part of the generated synthetic gas is supplied together with the high-temperature steam into the reaction chamber to activate the feedstock decomposition and increase the gas generation. The device contains the reaction chamber 4 with the power actuated screw pump 2, the swirler of the supplied superheated steam 24. The cavity of the chamber has the synthetic gas supply pipe to its purification 23, and it is also equipped with the part of the synthetic gas supply line again into the reaction area.

EFFECT: increase of the low-calorial brown coals gasification energy efficiency, productivity, synthetic gas quality, provision of the plant reliability.

2 cl, 5 dwg

Description

The invention relates to the field of heat transfer processes and is intended to produce high-energy synthesis gas, combustible generator and flue gases from low-calorie brown coal.

Brown coal is the most widespread type of low-grade coal in the countries of the European Union, Mongolia, the People’s Republic of China and other countries of the world. In particular, brown coal deposits are well developed in the Kansk-Achinsky and other brown coal basins and deposits of Russia, located from the European part to Sakhalin. Brown coals can have a low ash content - up to 20%, or high ash content - over 40%, but all brown coals, as a rule, are high-moist - with humidity up to 40-50%. Lignite of any grades can be easily gasified with the release of combustible generator gases, therefore their use for furnace purposes is economically advantageous in comparison with other carbon energy carriers, and in terms of its energy intensity, which is 5000 kcal / m ³ on average, synthesis gas for remote areas is quite competitive with natural gas.

The prior art various methods for the gasification of carbon-containing fuel. In particular, there is a known method of heat treatment of organic carbon materials [RU 1085509, 04/07/1984], which includes mixing the source material with a liquid, transporting the resulting mixture from bottom to top through a liquid layer with an adjustable level, supplying wet material to the reaction zone, processing it at high pressure and temperature to obtain gases and a solid product, the removal of the obtained gases and solid product, while the wet material is preheated before being fed into the reaction zone by passing through n its counterflow of gases obtained in the reaction zone.

The disadvantage of this method is the use of elevated pressure, elevated temperature and the need to heat the material before being fed into the reaction zone, which makes gasification more expensive and does not exclude its fire hazard.

A known method of processing coal into synthesis gas [RF No. 2190661, 10/10/2002], providing for crushing coal, obtaining dispersed fuel mass using mechanochemical activation, gasification of fuel in a tubular reactor.

This method involves the independent heating to 1000 ° C of the coolant supplied to the annulus of the reactor, which adversely affects the energy balance of the process as a whole, which complicates the hardware design of the process and reduces the efficiency of its use. A substantially high temperature (200-800 ° C) of the reaction between the organic part of coal and water vapor, however, will not allow for the efficient implementation of this process in the case of using low reaction coal. The resulting dispersed fuel system consists of relatively heavy colloidal particles and is subject to separation, which, together with the lack of technological methods and operating conditions for its purification from impurities before entering the reactor for gasification, will lead to the formation of scale in the pipes, reduce the rate of gasification reactions, and reduce useful the volume of pipes and, consequently, the volume of the fuel system processed per unit time, will lead to a decrease in the efficiency and reliability of the method, an increase in costs for maintenance and equipment maintenance.

A known installation for producing synthesis gas from water-carbon fuel [RU 2217477, 11/27/2003], using which a method of processing coal into synthesis gas is implemented, which includes obtaining a water-coal suspension, burning part of it to maintain the gasification process.

The known technical solution involves the use of flow swirls in the gasification chamber, which reduce the rate of gasification reactions and, consequently, the efficiency of the method implemented by the installation. In addition, an increase in the number of assembly units and, accordingly, surface area for unwanted deposits affects the reliability of operation. It is assumed that additional measures are needed to intensify heat transfer between the products of combustion of a water-coal suspension and its gasified part by installing additional heat pipes in the outer wall of the gasification chamber.

Known [I.S. Mezin, Transport gas generators] gas generator designs used in modern industry.

The essence of the processes proceeding in these constructions is as follows:

The source material (for example, brown coal) is loaded into the reaction chamber and subjected to thermal action with a lack of oxygen.

When heated, the starting material is dried and at a temperature of 400 ° C, the process of gasification of fuel begins, which ends with the complete decomposition of all organic components at a temperature of about 900 ° C.

The released gases partially burn out with a lack of oxygen with the release of heat.

Further, the gaseous reaction products pass through a layer of hot coke residue. In this part of the gasifier, a reduction reaction occurs, which goes with the absorption of heat.

To increase calorific value, water vapor is additionally added to the reduction reaction zone, which contributes to the formation of a large number of hydrogen-containing components with high energy saturation and a more complete extraction of carbon from the feedstock. Received gases heated to 1000 ° С mixed with dust are sent for cleaning, cooling and then to the consumer.

Inorganic reaction residues remain in the installation in the form of hot slag.

This method and the installation of its implementation to obtain synthesis gas has the following disadvantages:

The great complexity of organizing a continuous process of supplying raw materials and the subsequent removal of slag residue.

With the current level of technology and this method of producing gas synthesis, it is practically impossible to strictly control the process temperature and, when the temperature is exceeded, 1250 ° C, the process of melting and sintering of slags that are extremely difficult to remove from the installation begins.

On the other hand, raising the process temperature above 1600 ° С for guaranteed melting of slags and their removal from the plant in the form of a melt greatly increases the formation of nitrogen oxides with clear environmental and technical problems (in the presence of water vapor, nitrogen oxides form nitric acid vapor).

In addition, in the widely used designs of gas generators, the initial fuel is loaded in the form of relatively large pieces, which leads to low plant productivity, due to the small area on which oxidation-reduction reactions occur.

As a result, plants operating on the traditional principles of producing gas synthesis have extremely large dimensions, low productivity and great complexity of operation, which makes them unsuitable for use as part of industrial heat generators of high power.

Known vortex mill [RU No. 2048920], in which the initial product is loaded into a vertical, cylindrical grinding chamber, through an axial loading pipe, the output end of which is located at some distance from the bottom of the chamber along its axis. The gas grinding the material is supplied through nozzles of a special design located tangentially on the side surface of the chamber.

The output of the milled material is carried out through the side pipes, also located on the side surface of the grinding chamber. The exhaust gas is released through a nozzle located in the upper part of the side surface of the chamber connected to the grinding chamber by an axial hole through which the axial loading nozzle passes.

A significant drawback of the indicated design of the jet-vortex mill is that it requires a large flow of compressed gas for its operation. Which reduces the productivity and profitability of the synthesis gas production process.

The closest in technical essence is, according to the applicants, the method [RU No. 2190661, 10/10/2002] and the device of a vortex mill [RU No. 2048920], realizing the gasification of hydrocarbons, including low-calorie brown coals.

An object of the invention is to increase the energy efficiency of the process of gasification of low-calorie brown coal and increase productivity, as well as reducing the overall dimensions of the plants, improving the quality of the resulting synthesis gas and ensuring the reliability of the installation in a given process.

To solve the technical problem, the developed method for producing gas synthesis involves the simultaneous execution of drying, grinding, and gas generation operations in a cyclonic eddy upward flow in an environment of superheated water vapor.

The essence of the proposed method and device for generating gas synthesis is that drying, grinding and gas generation is carried out in one device, which is a continuous vortex grinding chamber, in which the working fluid is superheated to 1000 ° C water vapor mixed with products gas generation.

The heat required to start and maintain the gas generation reaction is not obtained from the partial combustion of the generated gases in the reaction chamber, but is delivered by superheated water vapor obtained from an independent source that is not part of the reaction chamber.

A method for producing synthesis gas from low-calorie brown coals with increased ash content, including disintegration of the feedstock, exposure to grinding by a high-temperature field, disintegration, drying and gas generation from feedstock are carried out while performing these operations by treating the feedstock with a cyclonic vortex high-temperature stream formed superheated steam and ascending gas-aerosol medium, while part of the gas-aerosol mass is used to form an ascending cyclonic water cartilage and synthesis gas.

A device for producing synthesis gas from low-calorie brown coal contains a chamber for processing feedstock connected to a source of high-temperature steam, while the chamber is made in the form of coaxially placed cavities forming a reaction chamber, an axial feeder is installed along the axis of this chamber, under which a flow divider is made on the bottom of the chamber, blades of a swirl of gel of the supplied steam and vapor-gas-aerosol mixture are mounted in the bottom of the chamber, in the middle part the chamber has a narrowing towards the bottom in the form of a truncated cone, Connections upper base of the cylinder, which is placed in the cavity of a hollow cylinder with a gap covering pshekovy feeder, with the top of the reaction chamber of the cylinder has a nozzle outlet of the synthesis gas and the pipeline connecting the cavity with the nozzle entry chamber high temperature steam.

A device for implementing a method for producing gas synthesis from low-calorie brown coal with increased ash content consists of a coal hopper, a screw batcher with a drive motor, a heat-insulated reaction chamber, a dust collector also coated with heat insulation, the receiving hopper of which is equipped with a cooling jacket, a heat exchanger-recuperator, and a swirl vapor condenser equipped with a cooling jacket, three control valves, a water supply tank, one main high pressure pump, three circulation GOVERNMENTAL pumps, three heat exchangers, steam generator, steam superheater unit and is equipped with automatic control.

A device for implementing the method is shown in the accompanying drawings,

Where:

- in FIG. 1 - functional diagram of the device and its connection;

- in FIG. 2 is a functional diagram of a reaction chamber;

- in FIG. 3 - diagram of the reaction chamber in sections aa,

- in FIG. 4 is a diagram of the reaction chamber in sections BB,

- in FIG. 5 is a diagram of the reaction chamber in sections BB.

A device for implementing the method comprises:

1. The coal bunker.

2. Screw feeder.

3. Drive motor.

4. The reaction chamber.

5. Dust collector.

6. Heat exchanger-recuperator.

7. Vortex vapor condenser.

8. The control valve gas mixture.

9. Control valve for chilled ash residue.

10. Contaminated condensate control valve.

11. Consumable water tank.

12. The main high pressure pump.

13. The primary circulation pump.

14. Secondary circulation pump.

15. Tertiary circulation pump.

16. The primary heat exchanger.

17. Secondary heat exchanger.

18. Tertiary heat exchanger.

19. The steam generator.

20. Superheater.

21. The control automation unit.

22. The outlet pipe gas mixture.

23. The outlet dust pipe.

24. Scapular swirls.

25. Steam inlet.

26. The outlet pipe synthesis gas.

27. Inkjet compressor.

28. Flow divider.

The direction of flow is shown by arrows.

The design of the reaction chamber is illustrated in the drawing (Fig. 2). The reaction chamber 4 is a three-sectional cylinder-conical structure. On the top cover of the reaction chamber 4, along the axis, there is a conical inlet of a cylindrical loading tube, the axis of which is equipped with an axial metering device 2 rotated by a drive motor 3, which feeds the reaction chamber 4 from the coal hopper 1 with feedstock (e.g., brown coal). The upper chamber, located under the cover of the reaction chamber 4, has an inlet pipe located on the axis of the structure, coaxial to the loading pipe. The gas mixture outlet pipe 22 is located radially on the lateral surface of the upper chamber through the gas mixture control valve 8 and is connected by a pipeline to the jet compressor 27. The middle chamber, of a cylindrical shape located under the upper chamber, is connected to the lower chamber by a narrow conical part, and to the upper chamber, by a nozzle located around the loading pipe. On the lateral cylindrical surface of the middle chamber, there is a dust outlet 23. A lower dust chamber 23 has an inlet annular channel at the inlet of which a jet compressor 27 and bladed swirlers 24 are inserted along the tangent along the generatrix of the mixture flow stream and the blade swirlers 24 along the entire height of the lower chamber. The lower end of the loading tube is located at some distance from the bottom of the lower chamber along its axis. The steam inlet 25 is connected to the superheater 20.

The device for implementing the method works as follows: From the supply water tank 11, the main high pressure pump 12 delivers water to the primary heat exchanger 16, then to the secondary heat exchanger 17 and through the tertiary heat exchanger 18, the heated water enters the steam generator 19.

The steam obtained in the steam generator 19 in the superheater 15 is heated to 1000 degrees Celsius and overheated water vapor is supplied to the jet compressor 27 through the inlet pipe 25 as an active stream. Passing the jet compressor, superheated steam draws in, heats and compresses the gas stream from the upper chamber. In the annular channel of the lower chamber, the mixed gas stream equalizes its temperature and pressure. Passing the blade vortexes 24, the mixed flow forms a vortex flow, rotating along the axis of the installation. Installed along the axis of the loading pipe, rotated by the drive motor 3, the axial feeder 2 feeds the feedstock (for example, brown coal) from the coal hopper 1 to the axial part of the vortex flow. The air necessary for the gas generation process enters the reaction chamber together with the feedstock. Chunks of raw materials picked up by the vortex flow, striking against each other and against the chamber walls, are crushed. Since the vortex flow has a high temperature (about 1000 ° C) and the crushed starting material has a large surface area, the gas generation process proceeds at a high speed, which guarantees a high productivity of the reaction chamber. At the same time, the process proceeds at a temperature significantly lower than the melting and sintering temperatures of inorganic residues, which eliminates the formation of hard to remove molten slag.

Since the temperature of the process does not exceed 1000 ° C, the formation of nitrogen oxides is negligible and the process is environmentally friendly.

The gas and dust flow, while maintaining a high rotation speed, washes the loading pipe and through a narrow conical part it enters the middle chamber, where it is divided.

The central, dust-free under the action of centrifugal forces, part of the flow through the connecting pipe enters the upper chamber, from where, through the gas mixture adjustment valve 8, it enters the jet compressor 27 as a passive stream. Using a regulator allows you to accurately control the process temperature according to the readings of temperature sensors located in each chamber (not shown in the diagram).

Repeated forced pumping of gas generation products through the reaction zone not only sharply reduces the required volume of superheated steam, but also contributes to a more complete processing of the feedstock, which guarantees high efficiency of the proposed reaction chamber.

The feed pipe, washed by the gas generation reaction products, is heated and, accordingly, dries and heats the feedstock supplied by a screw feeder.

Such a scheme for supplying raw materials avoids sharp thermal shocks when cold raw materials enter the hot reaction chamber, which ensures the reliability and durability of the reaction chamber.

The peripheral part of the stream, together with the dusty inorganic ash residues, leaves the reaction chamber through the dust outlet 23 and then goes to the dust collector 5, the separation chamber of which is coated with thermal insulation to reduce heat loss.

Separated red-hot ash residue is deposited in the dust hopper receiving hopper equipped with a cooling jacket, where, having given heat to the heat carrier circulating by the action of the tertiary circulation pump 15 along the circuit: the cooling jacket is a tertiary heat exchanger 18, then it is removed from the disposal device through the ash control valve 9.

The gas stream having a high temperature, cleaned from dust, enters the heat exchanger - recuperator 6 and, having given heat to the heat carrier circulating under the action of the secondary circulation pump 14 along the circuit: the heat exchanger - recuperator 6-secondary heat exchanger 17, enters the vortex vapor condenser 7 equipped with a cooling jacket.

In the vortex vapor condenser 7, the vapor contained in the gas mixture condenses under the action of centrifugal-gravitational forces, giving off heat to the coolant circulating under the action of the primary circulation pump 13 along the circuit: cooling jacket - primary heat exchanger 16. The purified cooled synthesis gas through the outlet pipe synthesis gas 26 is supplied to the consumer .

The condensate that has evolved is removed from the device through the contaminated condensate control valve 10 for disposal.

The described method of gas generation and the device can be used not only for processing brown coal with high ash content into high-calorie gas synthesis, but also for processing almost any solid fuels and solid waste containing hydrocarbon components, practically regardless of their ash content.

The method and device is very relevant for use at thermal power plants operating on brown coals and high-ash coals in order to reduce harmful and smoke emissions into the air, since the grinding and gasification process itself takes place in a single unit using superheated steam in a fluidized bed and the high-energy synthesis gas formed as a result of the reaction is supplied to the burners of the thermal power station where it burns smokeless, ensuring the ecological purity of the process. Calculations show the promise of using this method and device for the industrial production of synthesis gas from low-calorie brown coal, as well as from oil shale. Reserves of these raw material sources are significant and are located in regions where there is a need for furnace and technical gas volumes. The use of synthesis gas instead of direct burning of brown coals will reduce by 99.0% the smoke emissions and odor from burning coal, and in addition, significantly (by 40-50%) reduce ash waste from the burnt coal.

Claims (2)

1. A method of producing synthesis gas from low-calorie brown coals with increased ash content, including disintegration of the feedstock, exposure to grinding by a high-temperature field, characterized in that disintegration, drying and gas generation from the feedstock are carried out while performing these operations by impacting the feedstock with a cyclonic swirl high-temperature flow generated by superheated steam and ascending gas-aerosol medium, while part of the gas-aerosol mass is used to form an ascending cycle a vortical vortex and synthesis gas. 2. A device for producing synthesis gas from low-calorie brown coal, containing a chamber for processing the feedstock, connected to a source of high-temperature steam, characterized in that the chamber is made in the form of coaxially placed cavities that form the reaction chamber, a screw feeder is installed along the axis of this chamber, under which a flow divider is made on the bottom of the chamber, blades of a swirl of the supplied steam and a vapor-gas-aerosol mixture are mounted in the bottom of the chamber, in the middle part the chamber has a narrowing towards the bottom in the form of a whisker ennogo cone connected to the upper base of the cylinder, which is placed in the cavity of a hollow cylinder with a gap encompassing the screw feeder, while the upper part of the reaction chamber of the cylinder has a nozzle outlet of the synthesis gas and the pipeline connecting the cavity with the nozzle entry chamber high temperature steam.

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