Coal mine gas is divided into high concentration gas and low concentration gas. High concentration gas refers to gas with gas concentration greater than 30%, and low concentration gas refers to gas with gas concentration lower than 30%.
Low-concentration gas power generation needs to solve two problems. First, the conditions of each coal mine are different, and the gas condition is changing at any time. The traditional generator set is difficult to “change invariably”; the second is the safety of low-concentration gas. Delivery problem.
Low concentration gas generator set:
The electronically controlled gas mixer technology can automatically control the air-fuel ratio  to adapt to the change of gas concentration. At the same time, the low-concentration gas safety conveying technology uses the fine water mist technology to solve the problem of safe ground transportation of low-concentration gas.
Academician Zhou of the Chinese Academy of Engineering believes that: "Low-concentration gas generator sets are suitable for the small amount of coal mines in China, which is called the golden key to crack the gas problem of coal mines in China."
Since 2004, Shengli Oilfield Shengli Power Machinery Group has started to develop and research on “coal gas water mist transport and power generation technology” and successfully tested it in the second year, so that low-concentration gas power generation technology has developed rapidly. At present, the total installed capacity reaches 435,000 KW, generating 2.61 billion KW·H per year and 870 million cubic meters of gas. The new version of the "Safety Regulations for Coal Mines" has clearly defined the use of gas with a concentration below 30% for the internal combustion engine. The fifth paragraph of Article 148 of the Regulations states:
When the concentration of gas extracted is less than 30%, it shall not be directly burned as gas. When used for power generation or other purposes of internal combustion engines, the utilization and transportation of gas shall be in accordance with the relevant standards and safety technical measures shall be formulated. This provides an institutional guarantee for low-concentration gas power generation. More than 60% of the gas in China's coal mines is low-concentration gas, which is the source of gas for low-concentration gas power generation in China. With the continuous improvement of low-concentration gas power generation technology, the low-concentration CBM power generation industry will have a benign scale development, which will generate more and more economic and social benefits.