Coal Bed Methane
Methane is a powerful green house gas, as its adverse impacts are felt more intensely due to its shorter residence and higher potency in the atmosphere than carbon dioxide.
Methane is associated with coal as a by product of the coal formation process. It is trapped in coal beds and released during and after mining. This methane does cause disasters in underground coal mines.
If effectively recovered, coal bed methane associated with coal reserves and emitted during coal mining could be a significant potential source of energy.
Methane capture and its utilization from coal mines is not being undertaken in India due to:
This project is a mine-related CMM demonstration project, which is under implementation at Sudamdih and Moonidih mines of BCCL, in the Jharia Coalfield, Jharkhand State of India. The project having a duration of 5 years, was approved by the Govt. of India at an estimated cost Rs. 76.85 crores.
The different collaborators and their contributions for funding the project is given below:
The CBM resources as per Directorate General of Hydrocarbons (DGH), Ministry of Petroleum & Natural Gas (MoP&NG) is tabulated here under :
Table : Prognosticated Resource of CBM
Brief description of the specific options for utilisation:
CBM can be ideal fuel for co-generation Power plants to bring in higher efficiency and is preferred fuel for new thermal power plant on count of lower capital investment and higher operational efficiency. On the basis of predicted per day recovery from the identified blocks, possible power which can be generated in Jharkhand State is tabulated below :
At the lower end of value, power generation of about 800MW in Jharkhand is possible from the identified blocks.
Auto Fuel in form of Compressed Natural Gas (CNG)
CNG is already an established clean and environment friendly fuel. Depending upon the avaibility of CBM, this could be a good end use. Utilization of recovered CBM as fuel in form of CNG for mine dump truck is already part of demonstration project titled “Coalbed Methane Recovery & Commercial Utilization Project” presently under implementation in collaboration with UNDP/GEF at Sudamdih and Moonidih mines of BCCL.
Feed Stock for Fertilizer
M/S Sindri Modernization Plant (SMP), Sindri is utilizing fuel oil as feedstock for its cracker complex. The installed capacity of this plant is 900 tonne per day ammonia and is operational at 80% of capacity during last three years. The CBM produced from Jharia, Bokaro coalfields can be utilized at Sindri, which will economise the operations.
Fuel for Industrial Use
It may provide an economical fuel for a number of industries like cement plant, refractories, Rolling mills etc. in Dhanbad, Bokaro, Palamu regions in view of the superior combustion properties of CBM. According to survey carried out by MECON (I) Ltd, there is demand of 5000000 Nm3 of natural gas/CBM in the Jharkhand state alone for industrial purposes.
Use of CBM at Steel Plants
Blast furnace operations use metallurgical coke to produce most of the energy required to melt the iron ore to iron. Since coke is becoming increasingly expensive in the U.S., the steel industry is seeking low-capital options that reduce coke consumption, increase productivity and reduce operating costs. All blast furnaces in North America inject some type of supplement fuel, such as natural gas, coke oven gas, oils and tars, or coal to form additional carbon monoxide and hydrogen for combustion, and chemical reduction of iron-bearing materials into molten iron. Of these fuels, natural gas and pulverised coal are the most widely accepted for injection. Recent full-scale tests have shown that injecting natural gas into blast furnaces at the rate of 195.4 cubic meters per ton of hot metal can reduce coke consumption by 30% , and can increase iron-making capacity by 40%. Coal mine methane provides the same benefits as conventional natural gas, and could easily be substituted for, or mixed with, natural gas for blast furnace use as long as it meets gas quality requirements (low sulfur content and at least 94% methane). Injection of CBM in blast furnace of Bokaro Steel Plant will improve performance and can enhance its productivity.
CMM use in Methanol Production
Methanol is a key component of many products, including MTBE (used in reformulated gasoline), methanol and gasoline blends (such as M 85 for flexible fuel vehicles), formaldehyde resins (widely used in the housing industry), and acetic acid, a major raw material in the chemical industry. Most of the world’s production of methanol uses natural gas as a feedstock, which is also the most important cost component. No methanol producers have coalbed methane, but it is a potential alternative feedstock to fuel large methanol plants in areas that mine gassy coal. Smaller (11.4-15 million liters/year) mobile methanol plants used at off-shore oil rigs may be a potential option for use at coal mines. Gas quality should be at least 89% methane, up to 1% oxygen and up to 10% carbon dioxide.
Utilisation of Coal Mine Methane
Besides above utilization prospects, linkages of coal mine methane (CMM) produced as a result of degasification of coal mines in comparatively in smaller quantity through cross country pipe lines may not be economical and therefore can be utilized at mine sites itself.
Three strategies for developing the CBM resource associated with mining are proposed