Gas
Material, Processing and Power Technologies
Introduction
The coal mine methane (CMM) is preliminarily discharged from coal seams in underground coal mines for safety reasons, but the discharged CMM is usually emitted straight into the atmosphere, because most of the discharged CMM has a methane concentration of less than 30%. Methane is one of the greenhouse gases. Therefore, CMM emissions contribute to global warming. Osaka Gas has been working to develop the low-concentration CMM concentration technology in an effort to (i) achieve effective use as fuel for gas engines, gas boilers, etc, and (ii) promote energy-saving and environmental protection efforts.
Features
The low-concentration CMM concentration technology:
- Has been achieved to concentrate low-concentration CMM by utilizing Osaka Gas's unique material technology to selectively adsorb methane in the air-methane mixture.
- Enables effective use of methane, whose global warming effect is 21 times stronger than carbon dioxide. A standard unit to be commercialized (CMM flow rate: 2,000 m3/h) can reduce methane emissions of approx. 40,000 t-CO2 per year.
This technology makes low-concentration CMM (which has been released into the atmosphere) available in various forms, such as (i) fuels for gas engines and gas boilers, and (ii) city gas for household and industrial purposes.
Past achievements and Future effort
In fiscal years 2007 and 2008, Osaka Gas formed a joint research consortium (comprising five companies including two Chinese companies) to undertake a joint research project for “Development of Methane Concentration Technology Aimed at Effective Use of Low-concentration CMM (Coal Methane Gas)”, under the auspices of the New Energy and Industrial Technology Development Organization (NEDO). A CMM concentration demonstration plant (CMM flow rate: 1,000 Nm3/h) was built at the Fuxin Coal Mine in Liaoning Province, China, and low-concentration CMM extracted from the coal mine was successfully concentrated through demonstrations.
Currently, Osaka Gas has been working on NEDO’s “Clean Coal Technology Demonstration and Popularization Project (FS) for FY 2009” in an effort to be commercialized in China. Specifically, investigations and reviews have been performed regarding the introduction of CMM concentration plant, and feasibility studies have been carried out at specific coal mines with a view toward launching commercial projects early on.
Pilot Plant
Specifications of standard unit to be commercialized
| Feed gas flow rate | 2000 Nm3/h |
|---|---|
| Concentration Performance | 25 % or more |
| Methane recovery rate | 90 % or more |
| Operation | one-touch automatic operation |
| energy-saving | Approx. 3,000 kL/year |
| greenhouse gas emissions reduction | Approx. 40,000 t-CO2/year |
* Concentration performance (%) = Methane concentration in product gas - Methane concentration in feed gas
* Methane recovery rate (%) = (Methane concentration in product gas × Integrated volume of product gas) ÷ (Methane concentration in feed gas × Integrated volume of feed gas)
