RU2344163C1 - Method of coal conversion to synthesis gas - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention refers to thermal coal conversion to high-quality synthesis gas and can be used in chemical industry, for production of synthesis gas as fresh raw materials for chemical products, e.g. light hydrocarbons, in power engineering, in metallurgy for metal melt process. Offered method of coal conversion to synthesis gas includes as follows. Coal is crushed, supplied to preheated water tank, and mixed with soda ash added. Prepared mixture is mechanochemically activated, delivered through circulation loop with cavitator until suspension fuel dispersion is produced. Premagnetic suspension is split-fed to tubular reactor for gasification and burning to maintain process. Synthesis gas produced by high-speed suspension heating is purified and cooled in washing scrubber with circulating reused water with added calcium hydroxide. Derived residue is handled to reused water tank. Then synthesis gas is completely cooled in cooling condenser, where it is separated from aqueous condensate supplied to reused water tank.

EFFECT: intensification of gasification with simultaneous elimination of external heat-carrier, as well as reliable functional result of unballast end product process.

2 cl, 1 dwg

Description

The invention relates to the thermal processing of coal into high-quality synthesis gas and can be used in the chemical industry in the production of synthesis gas as a primary raw material for the production of chemical products, for example light hydrocarbons, in the energy sector, and in metallurgy during metal smelting.

A known installation for producing synthesis gas from coal-water fuel according to the patent of the Russian Federation No. 22177477 (publ. November 27, 2003, bulletin No. 33), using which a method of processing coal into synthesis gas is implemented, which includes obtaining a coal-water suspension, burning part of it to support the process gasification.

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.

The prior art method of processing coal into synthesis gas, adopted as a prototype, according to the patent of the Russian Federation No. 2190661 (publ. 10.10.2002, bulletin No. 28), providing for crushing coal, obtaining a dispersed fuel system using mechanochemical activation, gasification of fuel in a tubular the reactor.

The known method involves the independent heating to 1000 ° C of the coolant supplied to the annulus of the reactor, adversely affecting the energy balance of the process as a whole, 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 nevertheless does not allow to ensure the effective conduct of this process in the case of using low-reaction coal, for example anthracite. 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, therefore, 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 n and maintenance and equipment maintenance.

The objective of the proposed technical solution is to create a method for processing coal into synthesis gas, which provides an increase in the efficiency of producing synthesis gas by implementing conditions to intensify the process of gasification of the fuel system in the reactor by increasing its reactivity, sedimentation stability and minimizing the likelihood of unwanted interference for its movement in the tubes of the reactor while eliminating the use of an external coolant and ensuring reliable operation a national result for obtaining a ballasted target product while lowering the upper limit of the temperature range used for water decomposition.

The problem is solved by the proposed method of processing coal into synthesis gas, which involves crushing coal, obtaining a dispersed fuel system using mechanochemical activation, gasification of the fuel system in a tubular reactor. The peculiarity lies in the fact that before mechanochemical activation, crushed coal is fed into a container with preheated water for mixing in the presence of soda ash, the resulting mixture is subjected to mechanochemical activation by passing through a circulation circuit with a cavitator to obtain a dispersed fuel system in the form of a suspension with its subsequent direction in the supply tank, the suspension is magnetized and sent to the reactor in two streams, one stream to the reactor pipes for gasification, etc. oh - for combustion to maintain the process, the synthesis gas obtained as a result of high-speed heating of the suspension is cleaned and cooled in a scrubber-washer, in which circulating water with added calcium hydroxide is circulated, the resulting slurry is transported to a container with circulating water, and synthesis gas finally cooled in a refrigerator-condenser, where water condensate is separated from it and sent to a container with recycled water.

In particular, the sludge accumulating in the mixing tank and in the tank with recycled water is periodically drained.

A comparative analysis shows that the inventive method differs from the closest analogue by the presence of multi-aspect preparation of the fuel system before feeding directly to the reactor; using a coolant having a different origin — burning part of the obtained dispersed fuel system (in the prototype, the arrival of the coolant heated outside the main process is organized); another agent used to cool the synthesis gas is water (in the prototype, air); the presence of two-level cooling of the synthesis gas, one of which is combined with purification; other hardware design of the stage of separation of water condensate; lowering the upper limit of the temperature range used for water decomposition to 400 ° C (in the prototype - 800 ° C).

When creating methods for processing coal into synthesis gas, they usually focus on the optimal combination of process intensification and economic attractiveness. In the inventive method, a balance is achieved between a combination of basic technological parameters - high-speed pyrolysis and the use of thermal energy, the receipt of which is provided by the process itself.

The proposed method is illustrated by a graphic image (see drawing), which schematically shows the installation, on the example of which the embodiment of the method is characterized.

The installation contains a screw feeder 1 for feeding crushed coal into a container 2 with preheated water, a pump 3, a cavitator 4, a supply tank 5, a second pump 6, a magnetizing device 7, a reactor 8 with pipes 9 (shown conditionally) and a device 10 for burning part of the obtained fuel system, scrubber-washer 11, container 12 with recycled water, refrigerator-condenser 13. The magnetizing device 7 is a high-energy magnets installed in the housing with the formation of a working gap through which the suspension flows I am. Magnetizing devices are manufactured by industry. For example, Eniris-SG LLC (Moscow) produces hydromagnetic systems (HMS) of various models according to TU 3697-001-46492190-2000; MVS KEMA CJSC (Novosibirsk) produces magnetic water activators MPAV MVS KEMA according to TU 3697-001-76479620-05.

The method is as follows.

Crushed coal, the degree of grinding of which does not exceed 2 mm, is continuously supplied by a screw feeder 1 to a container 2, into which heated water is preliminarily filled from the cooling system of the target product and calcined soda is introduced. In addition to its catalytic properties, which lower the activation energy of the reaction of coal with water, soda ash has the ability to effectively bind sulfur, leaving it in the form of sulfates, and also improves the rheological properties of the resulting suspension, preventing its separation. In the process of circulating a mixture of coal, water and soda ash using pump 3 through cavitator 4, the mixture is crushed and homogenized, forming a suspension. Sludge accumulating in tank 2 and formed as a result of clogging of coal with waste rock and due to ultrafine cavitation grinding are periodically drained. The finished fuel system is transported to a supply tank 5 for further use. In the empty tank 2, the feedstock is reloaded. From the supply tank 5 by the second pump 6, the prepared suspension is magnetized to prevent scale formation in the pipes 9 of the reactor 8, passing through the device 7, where it receives additional activation, becomes more sedimentation resistant. Then, the magnetized suspension is fed in two streams into the pipes 9 of the reactor 8 for gasification and into the device 10 (for example, two burners) for combustion to obtain a heat carrier having a temperature of 1000-1200 ° C. The synthesis gas reaction occurs at a high speed for 0.2-2 seconds, after which the resulting synthesis gas, unreacted parts and ash residue are removed from the zone of the reactor 8. Next, the target product is sent for washing and cooling to the scrubber-washer 11. In the scrubber-washer 11 circulating water circulates from the tank 12 with calcium hydroxide added to it, which allows you to completely remove sulfur compounds, as well as catch particles of ash. The ash and the resulting gypsum are transported by washing water to a settling tank 12. As the accumulation of sludge (the amount depends on the ash content and the amount of sulfur in the coal), the latter is removed through the bottom drain. Floated unreacted coal fines (coke) are collected and returned to the beginning of the process in tank 2. The washed and purified synthesis gas is finally cooled in the condenser refrigerator 13. The resulting water condensate is taken into tank 12, and the gas (practically unballasted mixture of CO and H ₂ ) sent to the consumer.

The slurry from the tank 12 during thickening, for example, on a hydrocyclone is suitable for the production of building materials.

The proposed method is phased tested in the processing of ordinary coal grade "ZB" Munaysky deposits of the Altai Territory. Currently, work is underway to create a facility for processing coal into synthesis gas of the claimed method.

Claims (2)

1. A method of processing coal into synthesis gas, comprising crushing coal, obtaining a dispersed fuel system using mechanochemical activation, gasifying the fuel system in a tubular reactor, characterized in that before the mechanochemical activation, crushed coal is fed into a container with preheated water for mixing in the presence of soda ash, the resulting mixture is subjected to mechanochemical activation by passing through a circulation circuit with a cavitator to obtain a dispersion of the fuel system in the form of a suspension, followed by its direction into the supply tank, the suspension is magnetized and sent to the reactor in two streams, one stream to the gasification pipes of the reactor, the other to combustion to maintain the process, the synthesis gas obtained by high-speed heating of the suspension is purified and cooled in a scrubber-washer, in which circulating water is circulated with calcium hydroxide added to it, the formed sludge is transported to a container with circulating water, and the synthesis gas is finally cooled in a condenser lodilnik, where water condensate is separated from it and sent to a container with circulating water. 2. The method according to claim 1, characterized in that the sludge accumulating in the mixing tank and in the tank with circulating water is periodically drained.