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Gold/Mining/Energy : Global Thermoelectric - SOFC Fuel cells (GLE:TSE) -- Ignore unavailable to you. Want to Upgrade?

To: Gulo who wrote (5604)	9/9/2002 12:16:16 AM
From: CH4	Read Replies (1) \| Respond to of 6016

Coal beds: A source of natural gas Source: Oil & Gas Journal Publication date: 2002-08-01 Arrival time: 2002-09-07 Work by the Bureau of Mines has demonstrated that coal beds can yield substantial quantities of pipeline-quality natural gas. The estimated volume of gas contained in US. coals-some 300 trillion cu ft-is equivalent to the proved and currently recoverable reserves of natural gas in the US. And the necessary technology to drain and recover much of this gas is already available. Currently US. coal mines vent 200 MMcfd of natural gas to the atmosphere. Much of this wasted gas could be conserved by drainage in advance of mining. The value of the recovered gas, the relatively low capital investment and operating costs, the low exploration cost, and the high percentages of productive wells indicate that gas drained from coal beds is a potentially profitable source of fuel. How much gas in coal The amount of gas in coal is highly variable, and depends on such factors as porosity, permeability, and adsorptive capacity of the coal; the depth, pressure, degree of fracturing, and permeability of adjacent strata; and the distance from the outcrop. Experimentally determined values for relatively shallow U.S. coals range from 0.01 to 550 cu ft/ton. A conservative estimate of the average gas content of US. coals is 200 cu ft/ton. Minable coal beds with less than 3,000 ft of cover, excluding strippable coals, contain an estimated 1.5 trillion tons of coal, corresponding to an estimated 300 trillion cu ft of combustible gas (Table 1). To obtain a more specific value for the amount of gas in coal, a study was made of the Pittsburgh coal bed in southwestern Pennsylvania. Based on direct measurements, adsorption isotherms, and methane-emission rates of active mines, the Pittsburgh coal in this area is estimated to contain between 50 and 200 cu ft/ton, with the virgin reserves underlying a 575-sq-mile area containing about 599 billion cu ft of gas. Gas drained directly from coal beds is similar to natural gas in composition and heating value. Uncontaminated coal-bed gas generally contains in excess of 80% methane; varying amounts of N^sub 2^, O^sub 2^, and CO2 and small amounts of higher hydrocarbons hydrogen, and helium. It contains no sulfur compounds or carbon monoxide. The heating value of coal-bed gas is generally between 900 and 1,050 BTU/ scf Why drain gas from coal? There are several significant advantages to draining gas from coal beds in advance of mining. Not only would it improve mine safety and conserve a valuable energy resource, but the exploration cost is very low. The location of most coal beds is known, and even unmapped beds are readily located because of their distinctive response to gamma ray and hydrocarbon-emission logging. Potentially productive coal beds abound in the eastern and Midwestern United States, close to existing pipelines and established markets. Wells drilled into coal beds are relatively shallow, requiring minimal investment in time and equipment. Most U.S. coal beds occur at depths of less than 1,000 ft and are in the intermediate or thick categories. Drilling and stimulation techniques for draining coal beds are well developed, so that no technological breakthrough is needed to make draining coal beds feasible. Coal-bed gas generally requires no remedial treatment for use as fuel or feedstock gas. In most cases only a compressor and dewatering and metering equipment are needed to put coal-bed gas directly into a commercial pipeline. An additional advantage is that gas wells in properly selected coal beds have a high success rate, ranging from a minimum of 75% to a maximum 99%. How to obtain gas from coal Recent work by the Bureau of Mines has demonstrated several practical methods for draining gas from coal beds in advance of mining. In one experiment, a 48-in.-diameter shaft was drilled 839 ft to the Pittsburgh coal. In the coal, the hole was widened to a diameter of 14 ft, and seven horizontal degasification holes were drilled into the coal bed. The length of the 3-in.-diameter degasification holes ranged from 500 to 850 ft. Gas from the coal flows through a receiver tank and two 4-in. pipes to the surface. A compressor and 6-in. pipe deliver gas to a commercial pipeline. No stimulation technique is used to increase flow rates from the degasification holes. The coal contains an estimated 120 cu ft of gas/ton. The boreholes are currently draining gas at an average rate of 500 MMcfd with a water-flow rate of 0.25 gpm/hole. After 700 days of degasification, over 470 MMcf of gas has been removed from the coal bed through the horizontal degasification holes. Currently the gas is being added to a commercial pipeline at the rate of 500 MMcfd. The gas is 87% methane and requires no remedial treatment for acceptance into the gas company's supply line. Gas also can be drained from coal beds through small-diameter cased vertical boreholes (<9 in). A hydraulic stimulation technique is used to increase the permeability of the coal, enlarging the collection radius and insuring adequate gas-flow rates. Tests of this procedure conducted in the Pocahontas No. 3, Pittsburgh, and Mary Lee coal beds have shown five to 20-fold increases in gas production rates after hydraulic stimulation (Table 2). Flow rates of gas and water before and after stimulation of the Mary Lee coal demonstrate the efficiency of hydraulic stimulation. In 22 months before stimulation the boreholes drained 1.7 MMcf of gas; in 9 months after hydraulic fracturing 13.7 MMcf of gas was drained from the coal bed. The estimated drainage area for a single borehole is between 20 and 30 acres; 1,500 ft is considered optimum well spacing for smaller-diameter boreholes. Gas from vertical boreholes usually contains over 85% methane and can be introduced directly into commercial pipelines. Table 1 Table 2 Maurice Deal Ann G. Kimm U.S. Bureau of Mines Pittsburgh Copyright PennWell Publishing Company Aug 2002 Publication date: 2002-08-01 More information about coal bed methane ... matr.net ... September conference in Billings focuses on Coal Bed Methane and Montana's energy future matr.net ... Global Thermoelectric Inc.'s fuel cell systems to be tested at Montana State University Billings ... (excerpt) "This is an excellent opportunity for Global to work with others who share a similar commitment to developing new power generation products and also building markets for them," said Jim Barker, Global's Vice President, Business Development. "MSUB's role, like that of our other partners, will be to define the needs, scope and distribution channels of different early adopter markets as well as to test and demonstrate our fuel cell products. Also, we plan to test our systems using well-site gas as the feedstock for our fuel cell to demonstrate the fuel flexibility of our SOFC products," added Mr. Barker. Under the terms of the agreement with MSUB's Center for Applied Economic Research, Global will provide a 2kW natural gas fueled residential system and a 3-5 kW methane fueled remote power system for light industrial applications to MSUB for MSUB and MDU to test and evaluate. The two systems will be delivered over the next year for anticipated proceeds of US$125,000 to Global.