Current Situation of Low Concentration Methane Utilization

Low concentration methane has a large emission volume

• In 2018, the global coal mine methane leakage was 40 million tons, equivalent to the emission of 1 billion tons of CO2 equivalent greenhouse gases. China’s emissions account for over half of the total global methane emissions from coal mining.
• In 2018, China extracted 13 billion cubic meters of gas, of which 5.3 billion cubic meters with a concentration greater than 9% were utilized, with a utilization rate of 40.7%.
• During the coal mining process, about 60% -70% of the low concentration gas is below 9%, with a utilization rate of only 2%. Most of it is not utilized and directly discharged and leaked into the atmosphere, polluting the environment.
• China’s coal mines emit a total of 24 billion cubic meters of methane into the atmosphere every year, accounting for one-third of the total industrial methane exhaust volume and generating 200 million tons of carbon emissions.
• Gas is flammable and explosive (5%~15%) (safety issue).

Methane gas properties: fuel+non CO2 greenhouse gases

• Methane Gas is a clean fuel resource.
• Gas (methane) is a greenhouse gas. The greenhouse effect of methane has a “100 year time frame warming potential GWP” that is 28 times that of carbon dioxide.
• Deep reduction of methane emissions will be a necessary condition for achieving global warming control below 1.5 ℃.
• In January 2021, the Ministry of Ecology and Environmental Protection pointed out the need to strengthen greenhouse gas monitoring and gradually incorporate it into the overall implementation of the ecological environment monitoring system. At the level of key emission point sources, pilot projects will be carried out to monitor methane emissions in key industries such as oil and gas, coal mining, etc.
• The restart of the National Certified Voluntary Emission Reduction (CCER) program is imminent. (Calculated at 50 yuan/ton, equivalent to a gas value of approximately 0.75 yuan/Nm3).
• The oxidation and destruction of exhaust gas will become one of the directions for methane emission reduction in the future.

Reuse mode of low concentration methane

Cascade and Management of Methane Concentration in Coal Mines
(Taking China as an Example in 2020)

Thermal Storage and Oxidation Energy Cascade Utilization Technology

Process flow diagram

Safe transportation and blending of low concentration CH4 and Vam

• Function:
  Safely transport low concentration gas from the exhaust end to the gas consumption end, and ensure the quality of the transported gas; The exhaust end involved is a gas extraction station, and the gas end involved is a blending system.
  
• Встановлення:
  The three-way pipe directly connected to the exhaust outlet of the gas extraction station does not require pipeline modification.

Main Equipment ① — Electric release valve

• Principle and Function:
  The electric release device is mainly used to achieve emergency release of system pressure, installed at the beginning and end of the conveying pipeline, and focuses more on the protection of coal mine gas drainage stations and blending systems.
• Installation requirements:
  Installed on the end discharge pipe of the conveying pipeline and the outlet exhaust pipeline of the coal mine gas drainage station. A dry flame arrester should be installed at the rear end of the release valve to ensure that the released gas does not affect the pipeline;

Main Equipment ② — Powder automatic powder spraying and explosion suppression device

• Principle and Function:
  The electric release device is mainly used to achieve emergency release of system pressure, installed at the beginning and end of the conveying pipeline, and focuses more on the protection of coal mine gas drainage stations and blending systems.
• Installation requirements:
  Installed on the end discharge pipe of the conveying pipeline and the outlet exhaust pipeline of the coal mine gas drainage station. A dry flame arrester should be installed at the rear end of the release valve to ensure that the released gas does not affect the pipeline;

Main Equipment ③ —Powder automatic powder spraying and explosion suppression device

• Principle and Function:
  The electric release device is mainly used to achieve emergency release of system pressure, installed at the beginning and end of the conveying pipeline, and focuses more on the protection of coal mine gas drainage stations and blending systems.
• Installation requirements:
  Installed on the end discharge pipe of the conveying pipeline and the outlet exhaust pipeline of the coal mine gas drainage station. A dry flame arrester should be installed at the rear end of the release valve to ensure that the released gas does not affect the pipeline;

Main Equipment ⑥ —Dry flame arrester

• Principle and Function:
  The high-efficiency composite gas-liquid separator has multiple functions such as dehydration, dust removal, and pressure stabilization, and is a gas purification treatment equipment.
  Adopting cyclone separation technology, utilizing centrifugal force for gas-liquid separation. The separated water flows down along the cylinder wall, while the gas spirals up along the cylinder wall and enters the gas end through the secondary purification effect of the top separation layer, achieving the purification of the gas and meeting the gas indicators required by the gas engine.

Mixing System

Blender – Simulation Analysis