Coal underground gasifier technology

It is currently in the experimental stage and is technically difficult. The scale that can be achieved is around 40Nm3/h. Personally, I estimate that industrialization still has a long way to go.

According to online inquiries, some coal mines are in the industrial production stage and have passed appraisals. If it is really as described? Wouldn’t my country, a coal-rich country, enjoy a bumper harvest?

It takes a long time for a new technology to be developed and matured into industrial production. We hope to see the successful application of this technology as soon as possible. :lol

Why are you bringing this up? My heart hurts. I came from the underground gasification center back then. I feel so far away from this:'(

Let me tell you objectively, this technology is not very mature. The key is that it is difficult to control the measurement and control of underground parameters.

Please help "zhaomingucg" Haiyou, can you be more specific? This is very important for our investment, thank you again!

This technology was tested by the China University of Mining and Technology in the mines of the Xukuang Group in the 1990s, and there have been no reports of industrialization. The previous difficulty with this technology was that it was difficult to control the production temperature of the coke ring after underground coal seam gasification.； If a strong coke ring is not formed, the voids in the coal seam formed after combustion will collapse, and subsequent coal seams will not be able to contact the air for anaerobic reactions.

In other words, this technology has good prospects. It is actually divided into well-type gasification and well-less gasification. Among them, well-less gasification is already being done abroad, especially in the former Soviet Union, and Australia is also currently conducting such experiments. Well-type gasification is mainly used in China to mine Sanxia coal. It is said to be a promising technology, but the current domestic technology in this area is not mature enough, mainly because the gas output is not stable enough. As long as you devote yourself to research, there should be no problem within 20 years.

“"Coal underground direct gasification furnace technology" should be "coal underground direct gasification technology". ——There are many technical problems in this technology, which are difficult to overcome, and the geological conditions vary greatly in different locations.

Does that mean that at present, this underground coal gasification technology lacks practical operability in my country?

I feel that underground gasification is really not feasible and is a last resort. It can be studied as a subject. If it is industrialized, I feel that it will cut off the road for future generations. Personally think: 1. Move the danger from the ground to the underground, making it more difficult to avoid it. ； 2. Transferring pollution from the ground to the underground increases the difficulty of treatment. ； 3. Using resources below the ground only deeply damages the environment, and the advantages far outweigh the disadvantages. ； 4. There will be a phenomenon of "big steel smelting", which will make resources look different and turn them into waste products. This post was last edited by GSP on 2009-4-28 16:46 ]

At present, underground coal gasification projects have not yet achieved industrialization internationally. Personally, I think there are many problems with the development of this technology: First of all, controlling the underground gasification and combustion process is a difficult point. Secondly, after underground gasification, there will be problems such as geological structures and re-mining of residual coal (incomplete utilization of resources). The development of this technology still has a long way to go.

Personally, I feel that the underground coal gasification project has good development prospects. Although it has not yet been industrialized and there are some problems, any new project or technology cannot be developed in one or two years. It will gradually solve problems and improve with people's gradual understanding of technology and the continuous progress of science and technology. Underground coal gasification technology is a multi-disciplinary development of clean energy and chemical raw materials that integrates well construction, coal mining, and conversion processes. The essence of this new technology is to transform physical coal mining into chemical coal mining, extracting only the useful components of coal rather than mining itself. It realizes an underground unmanned and equipment-free production working surface. It can fully recycle and utilize coal resources, fully guarantee the personal safety of production personnel, reduce damage to the surface environment, achieve clean combustion and provide raw materials for the development of coal chemical industry and ideal new energy. Therefore, it has the advantages of safety, efficiency, less pollution, etc., and is conducive to environmental protection and ecological balance. This is a very promising method and means for the modern society with depleted resources and increasingly environmentally conscious society, and it will definitely be industrialized in the near future.

Gasification technology definitely lacks practical operability, and we look forward to the mature application of the technology.

From the perspective of chemical technology, underground coal gasification is a complete gasification process. The study of gasification methods is the sum of certain technical means to solve the chemical process problems of coal gasification. The underground gasification of coal is different from the gasification of surface gas generators. The coal does not move, but is an organized moving reaction zone - that is, a moving flame working surface. Therefore, when classifying according to chemical process characteristics, the flame working surface, wind flow and gas movement direction can be used as classification signs of gasification methods. Based on this, gasification methods can be divided into four types: (1) Forward gasification method ； (2) Reverse gasification method ； (3) Post-degradation method ； (4) Continuous gasification method From the perspective of mining technology, we divide gasification methods into the following categories. 1． This underground gasification method of coal seam permeation gasification treats a gasification zone of the coal seam as a natural coal seam with pores and fissures, and also takes into account that as the coal seam heats up, the jointness of the coal seam increases. When using this method to gasify, the coal seam must be ignited, and air must be blasted into the coal seam through blast boreholes. The blown wind then penetrates into the exhaust holes along the natural pores and fissures of the coal seam. 2. Gasification Method of Artificially Broken Coal Seams Considering the difficulty of using natural pores and fissures in coal seams for coal seam gasification, a gasification method using artificially created pores and fissures in coal seams was tested. 3． In-bore gasification method In order to simplify the preparation of gasified coal seams, another method has been tested, which is to use the coal seam to drill some boreholes close to each other, instead of breaking the coal seam. This method also forms a large number of artificial fissures in the coal seam, but the cross-sections of these fissures are much larger than natural fissures. Therefore, the required air volume can be guaranteed even when the wind pressure is low. However, this method requires drilling many parallel boreholes in the coal seam. The spacing between boreholes is required to be equal to the thickness of the coal seam. This method is not suitable for thin or medium-thick coal seams because it is easy to deflect the boreholes into the roof floor or penetrate each other. This type of method has many practical applications. 4． Channel gasification method This gasification method is implemented in the gasification channel (Figure 7-9). When using this method, it is first necessary to dig a channel of appropriate cross-section in the coal seam. The resistance of the channel should be able to meet the air volume that can pass under economic wind pressure. Channel gasification method is also called continuous gasification method. The channel should be opened to ensure that air enters from one end and gas is discharged from the other end. There are many structural systems for this underground gasification method. When designing these structural systems, we must consider both the geological conditions of the coal seam and the technical level of building underground gas generators. A common structural system is to drill vertical boreholes from the ground to the coal seam, and then open up gasification channels (through or open coal lanes) in the coal seam between the boreholes to carry out gasification.

Underground gasifier type When gasifying coal seams underground, in order to break and loosen the coal seams, increase cracks and pores, and make them have similar conditions to the gasified coal seams in the above-ground furnace, the underground coal seams must be processed before gasification. This kind of work of processing coal seams to prepare gasification conditions before gasification is divided into well-type underground gasification, well-less underground gasification and hybrid underground gasification according to different preparation methods. The established underground gasifiers are respectively called well-type underground gasifiers, well-less underground gasifiers and hybrid underground gasifiers.