Coal catalytic gasification system

Abstract

This invention discloses a coal catalytic gasification system, comprising a fluidized bed gasification system, a slag tank, and an underground gasifier. The slag discharge port of the fluidized bed gasifier and the discharge port of the dust removal device of the fluidized bed gasification system are both connected to the inlet of the slag tank. The discharge port of the slag tank is connected to the air inlet of the underground gasifier. The air outlet of the underground gasifier is connected to the air inlet of the dust removal device via a pipeline. The advantages are: combining the fluidized bed gasifier and the underground gasifier allows the solids in the crude coal gas products obtained from both gasifiers to be returned to the slag tank, and combined with the ash and slag discharged from the bottom of the fluidized bed gasifier, which is then transported to the underground gasifier, reducing ash and slag emissions from the fluidized bed gasifier and minimizing environmental pollution; simultaneously, the low-cost catalyst in the ash and slag of the catalytic gasifier plays a further catalytic role in the underground gasifier, increasing the reaction intensity and maximizing the utilization of the low-cost catalyst.

Description

Technical fields:

[0001] This invention relates to a coal catalytic gasification system, belonging to the coal chemical industry. Background technology:

[0002] Coal energy, as a crucial component of the energy structure, plays a vital role in ensuring energy supply security. The coal chemical industry serves as a powerful means to achieve efficient utilization of coal resources. Coal gasification holds an important position in the coal chemical industry, producing various gaseous fuels, which are clean energy sources that contribute to improving people's living standards and protecting the environment.

[0003] Coal gasification processes are classified into surface coal gasification processes and underground coal gasification processes, depending on whether coal is mined.

[0004] Coal gasification is one of the main methods for producing syngas. The gasification process converts solid coal into gaseous syngas, while producing byproducts such as steam, tar (in some gasification technologies), and ash. Coal surface gasification processes can be classified into three main categories based on their technical characteristics: fixed-bed gasification, fluidized-bed gasification, and entrained gasification. Among these, catalytic fluidized-bed gasification, under the action of a multifunctional catalyst, allows coal and gasification media (steam, oxygen, etc.) to simultaneously undergo three reactions in a single reactor: coal gasification, water-gas shift reaction, and methanation. This effectively couples endothermic and exothermic reactions, significantly improving methane yield and system energy efficiency. In this process, catalyst recovery and energy efficiency have become key focuses for research and development companies. Currently, in actual production, catalyst recovery requires additional equipment for physical and chemical reactions, consuming labor, reagents, water, and electricity, increasing equipment investment and energy consumption. Furthermore, 100% recovery cannot be guaranteed, resulting in a high proportion of catalyst costs in production costs. Therefore, in actual production, due to limitations in investment and operating processes, the application of low-cost catalysts has become a research and development direction for enterprises. Because of their low price, these catalysts are generally not recycled, meaning they are discharged with the ash after completing their one-time catalytic efficiency in the catalytic gasifier. Obviously, the catalyst-containing ash discharged from the catalytic gasifier requires a fixed storage site and is environmentally unfriendly. Considering that low-cost catalysts still retain activity after a single catalytic reaction, utilizing the catalytic efficiency of low-cost catalysts after a single use has become a research topic that needs to be studied.

[0005] Underground coal gasification is a chemical mining method that directly gasifies coal into coal gas within underground coal seams. Through boreholes or shafts, ignition is performed within the coal seam, and a suitable amount of reactant (such as air or oxygen-enriched air and water vapor) is continuously supplied, causing a thermochemical reaction in the coal to produce coal gas. This gas is then transported to the surface via pipelines for use. Underground gasification fundamentally eliminates underground operations in coal mining, transferring the energy contained in the coal seam to the surface in a clean manner, while residues and waste liquids remain underground. This significantly reduces environmental pollution caused by coal mining and gasification, and also reduces safety accidents. An underground gasifier consists of an intake well, a gasification channel, an outlet well, and auxiliary monitoring wells. The gasifying agent is injected from the intake well and undergoes a complex thermochemical reaction with the coal seam within the gasification channel. The generated coal gas is then transported to the surface along the gasification channel and the outlet well. However, as the gasification reaction proceeds, the coal in the reaction zone is gradually consumed, causing the space inside the gasifier to slowly increase. This objectively leads to a slow increase in the reaction zone of the gasifier. If a certain supply of gasifying agent is maintained, the intensity of the gasification reaction and the gasification efficiency will decrease. Summary of the Invention:

[0006] The purpose of this invention is to provide a coal catalytic gasification system that reduces ash and slag generated in coal gasification processes and increases the gas production rate of underground coal gasification.

[0007] This invention is implemented by the following technical solution: a coal catalytic gasification system, comprising a fluidized bed gasification system, a slag tank, and an underground gasifier; the slag discharge port of the fluidized bed gasifier and the discharge port of the dust removal device of the fluidized bed gasification system are both connected to the feed port of the slag tank; the discharge port of the slag tank is connected to the air inlet of the underground gasifier; and the air outlet of the underground gasifier is connected to the air inlet of the dust removal device via a pipeline.

[0008] Preferably, the fluidized bed gasification system includes the fluidized bed gasifier and the dust removal device, wherein the gas outlet of the fluidized bed gasifier and the gas inlet of the dust removal device are connected by a pipeline.

[0009] Preferably, a slag cooling device is provided between the slag discharge port of the fluidized bed gasifier and the feed port of the slag pot.

[0010] Preferably, the slag cooling device is either a dry slag discharge machine or a slag cooler.

[0011] Preferably, the slag cooling device comprises a slag remover and a water slag dryer connected in sequence. The inlet of the slag remover is connected to the slag discharge port of the fluidized bed gasifier, and the outlet of the water slag dryer is connected to the inlet of the slag tank.

[0012] Preferably, check valves are provided on the pipes between the gas outlet of the fluidized bed gasifier and the gas inlet of the dust removal device, and on the pipes between the gas outlet of the underground gasifier and the gas inlet of the dust removal device.

[0013] Preferably, the air intake well of the underground gasifier is either a vertical shaft or an inclined shaft.

[0014] Advantages of this invention: Compared with the prior art, this application combines a fluidized bed gasifier and an underground gasifier, allowing the solids in the crude coal gas products obtained from both the fluidized bed gasifier and the underground gasifier to be returned to the slag tank. Combined with the ash and slag discharged from the bottom of the fluidized bed gasifier being transported to the underground gasifier, this reduces the ash and slag emissions generated by the fluidized bed gasifier and reduces environmental pollution. At the same time, the low-cost catalyst in the ash and slag of the catalytic gasifier plays a further catalytic role in the underground gasifier, improving the reaction intensity of the underground gasifier and maximizing the utilization of the low-cost catalyst. Attached image description:

[0015] Figure 1 This is a schematic diagram of the system connection in Example 1.

[0016] Figure 2 This is a schematic diagram of the system connection in Example 2.

[0017] Figure 3 This is a schematic diagram of the system connection in Example 3.

[0018] Fluidized bed gasification system 1, fluidized bed gasifier 11, dust removal device 12, slag tank 2, underground gasifier 3, check valve 4, slag cooling device 5, slag remover 51, water slag dryer 52. Detailed implementation method:

[0019] Example 1: As Figure 1As shown, the coal catalytic gasification system includes a fluidized bed gasification system 1, a slag tank 2, and an underground gasifier 3. The fluidized bed gasification system 1 includes a fluidized bed gasifier 11 and a dust removal device 12. The outlet of the fluidized bed gasifier 11 and the inlet of the dust removal device 12 are connected by a pipeline. The dust removal device 12 collects fine ash powder from the generated gas to avoid affecting the subsequent processing efficiency and application effect of the generated gas. The fine ash powder collected in the dust removal device 12 is sent into the slag tank 2. A check valve 4 is installed on the pipeline between the outlet of the fluidized bed gasifier 11 and the inlet of the dust removal device 12. The slag discharge port of the fluidized bed gasifier 11 and the discharge port of the dust removal device 12 are both connected to the inlet of the slag tank 2. The discharge port of the slag tank 2 is connected to the underground gasifier 3. The gas inlet well of the underground gasifier 3 is connected; the dry ash in the slag tank 2 is sent into the gasification zone of the underground gasifier 3 through the gas inlet well of the underground gasifier 3, so that the ash containing low-cost catalyst produced by the fluidized bed gasifier 11 is transported to the underground gasifier 3, so that the combustion air zone of the underground gasifier 3 does not gradually expand and its gasification intensity is guaranteed, while the remaining low-cost catalyst in the ash containing low-cost catalyst can participate in the catalytic gasification reaction of the underground gasifier 3; the gas inlet well of the underground gasifier 3 can be either a vertical shaft or an inclined shaft; the gas outlet well of the underground gasifier 3 is connected to the gas inlet of the dust removal device 12 through a pipeline, and a check valve 4 is installed on the pipeline between the gas outlet of the underground gasifier 3 and the gas inlet of the dust removal device 12.

[0020] Example 2: As Figure 2 As shown, the coal catalytic gasification system includes a fluidized bed gasification system 1, a slag tank 2, and an underground gasifier 3. Its overall structure is the same as that of Example 1, except that a slag cooling device 5 is provided between the slag discharge port of the fluidized bed gasifier 11 and the feed port of the slag tank 2 to cool the ash and slag discharged from the fluidized bed gasifier 11. The slag cooling device 5 can be either a dry slag discharger or a slag cooler.

[0021] Example 3: As Figure 3 As shown, the coal catalytic gasification system includes a fluidized bed gasification system 1, a slag tank 2, and an underground gasifier 3. Its overall structure is the same as that of Example 1. The difference is that a slag cooling device 5 is provided between the slag discharge port of the fluidized bed gasifier 11 and the feed port of the slag tank 2 to cool the ash discharged from the fluidized bed gasifier 11. The slag cooling device 5 consists of a slag remover 51 and a water slag dryer 52 connected in sequence. The feed port of the slag remover 51 is connected to the slag discharge port of the fluidized bed gasifier 11, and the discharge port of the water slag dryer 52 is connected to the feed port of the slag tank 2.

Claims

1. A coal catalytic gasification system, characterized by, It comprises a fluidized bed gasification system, a slag tank and an underground gasification furnace; the slag discharge port of the fluidized bed gasification furnace of the fluidized bed gasification system and the discharge port of the dust removal device of the fluidized bed gasification system are communicated with the feeding port of the slag tank; the discharge port of the slag tank is communicated with the gas inlet well of the underground gasification furnace; the gas outlet well of the underground gasification furnace is communicated with the gas inlet port of the dust removal device through a pipeline.

2. The catalytic gasification system of claim 1, wherein, The fluidized bed gasification system comprises the fluidized bed gasification furnace and the dust removal device, and the gas outlet port of the fluidized bed gasification furnace is communicated with the gas inlet port of the dust removal device through a pipeline.

3. The catalytic gasification system of claim 1, wherein, A slag cooling device is arranged between the slag discharge port of the fluidized bed gasification furnace and the feeding port of the slag tank.

4. The catalytic gasification system of claim 3, wherein, The slag cooling device is any one of a dry slag discharge machine or a slag cooler.

5. The catalytic gasification system of claim 3, wherein, The slag cooling device is a slag dredger and a water slag dryer connected in sequence, the feeding port of the slag dredger is communicated with the slag discharge port of the fluidized bed gasification furnace, and the discharge port of the water slag dryer is communicated with the feeding port of the slag tank.

6. The coal catalytic gasification system according to any one of claims 1 to 5, characterized by, A check valve is arranged on the pipeline between the gas outlet port of the fluidized bed gasification furnace and the gas inlet port of the dust removal device and on the pipeline between the gas outlet port of the underground gasification furnace and the gas inlet port of the dust removal device.

7. The coal catalytic gasification system according to any one of claims 1 to 5, wherein The gas inlet well of the underground gasification furnace is any one of a vertical shaft or an inclined shaft.

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