1、PDF外文：http:/ 附 录 附录 A： 英文翻译（原文） Status of worldwide coal mine methane emissions and use Abstract: Underground coal mines worldwide liberate an estimated 2941109 m3 of methane annually, of which less than 2.3109 m3 are used as fuel. The remaining methane is emitte
2、d to the atmosphere, representing the loss of a valuable energy resource. Methane is also a major greenhouse gas and is thus detrimental to the environment when vented to the atmosphere. Coal mine methane recovery and use represents a cost-effective means of significantly reducing methane emissions
3、from coal mining, while increasing mine safety and improving mine economics. The worlds ten largest coal producers are responsible for 90% of global methane emissions associated with the coal fuel cycle. China is the largest emitter of coal mine methane, followed by the Commonwealth of
4、Independent States, or CIS particularly Russia, Ukraine and Kazakhstan, the United States, Poland, Germany, South Africa, the United Kingdom, Australia, India and the Czech Republic. Most of these countries use a portion of the methane that is liberated from their coal mines, but the utilization rat
5、e tends to be low and some countries use none at all. Coal mine methane is currently used for a variety of purposes. Methane is used for heating and cooking at many mine facilities and nearby residences. It is also used to fuel boilers, to generate electricity, directly heat air for mine ventilation
6、 systems and for coal drying. Several mines in the United States sell high-quality mine gas to natural gas distributors. There are several barriers to decreasing methane emissions by increasing coal mine methane use. Many of the same barriers are common to a number of the subject countries. T
7、echnical barriers include low-permeability coals； variable or low gas quality, variations in gas supply an demand and lack of infrastructure. Economic and institutional barriers include lack of information pertinent to development of the resource, lack of capital and low natural gas pri
8、ces. A possible option for encouraging coal mine methane recovery and use would be international adoption of a traceable permit system for methane emissions. Keywords: coalbed methane； global warming； coal mining； natural gas 2 1 Introduction In recent years, coalbed methane has gained a
9、ttention as a saleable natural gas resource. Methane can be extracted either from coal seams which will never undergo mining, or it can be produced as a part of the coal mining process. This paper focuses on methane which is produced in conjunction with coal mining operations（ coal mine methan
10、e） . According to the United States Environmental Protection Agency （ USEPA, 1994a） , underground coal mines liberate an estimated 29 to 41109 m 3of methane annually, of which less than 2.3109 m3 are used as fuel. The remaining methane is vented to the atmosphere, representing the loss o
11、f a valuable energy resource. This paper examines the potential for recovering and using the methane which is currently being emitted from coal mines. There are three primary reasons for recovering coal mine methane. The first reason is to increase mine safety. Worldwide, there have been thousands o
12、f recorded fatalities from underground mine explosions in which methane was a contributing factor. Using methane drainage systems, mines can reduce the methane concentration in their ventilation air, ultimately reducing ventilation requirements. The second reason is to improve mine economics. By red
13、ucing emissions and preventing explosions and outbursts, methane drainage systems can cost effectively reduce the amount of time that the coal mine must curtail production. Moreover, recovered methane can be used either as fuel at the mine site or sold to other users. The third reason for coalbed me
14、thane recovery and use is that it benefits the global and local environment. Methane is a major greenhouse gas and is second in global impact only to carbon dioxide； methane thus is detrimental to the environment if vented to the atmosphere. Although the amount of carbon dioxide accumulating in the
15、atmosphere each year is orders of magnitude larger than that of methane, each additional gram of methane released to the atmosphere is as much as 22 times more effective in potentially warming the Earths surface over a 100-year period than each additional gram of carbon dioxide (USEPA, 1994a) . Comp
16、ared with other greenhouse gases, methane has a relatively short atmospheric lifetime. The lifetime of methane (defined as its atmospheric content divided by its rate of removal) is approximately 10 years. Due to its short lifetime, stabilizing methane emissions can have a dramatic impact on decreas
17、ing the buildup of greenhouse gases in the atmosphere. Coal mine methane recovery and use represent a cost-effective means of significantly reducing methane emissions from coal mines. Methane, moreover, is a remarkably clean fuel. Methane combustion produces no sulfur dioxide or particulates and onl
18、y half the amount of carbon dioxide that is associated with coal 3 combustion on an energy equivalent basis. Because of the environmental impact of coal mine methane emissions, the USEPA, the International Energy Agencys Coal Advisory Board (CIAB), and others have investigated methane emissions from
19、 coal mining worldwide. The USEPA (1994a) estimates that the coal fuel cycle (which includes coal mining, post-mining coal transportation and handling, and coal combustion) emits 35 to 59109 m3 of methane to the atmosphere annually. Table 1 shows methane emissions from the worlds ten largest coal pr
20、oducers, which are responsible for 90% of global methane emissions associated with the coal fuel cycle. Underground coal mining is the primary source of these emissions, accounting for 70 to 95% of total emissions. There are many opportunities for decreasing coal mine methane emissions by increasing
21、 recovery of this abundant fuel. Section 2 examines the status of methane recovery and use in key countries worldwide. 2 Coal mine methane recovery and use in selected countries 2.1 China The Peoples Republic of China (China) produces about 1.2109 raw tons of hard coal annually (EIA, 1996). In 1990,
22、 coal mining activities in China emitted an estimated 14 to 24109 m3 (10 to 16106 ton) of methane to the atmosphere, contributing one-third of the worlds total from this source. Not only is China the largest coal producer in the world； it is unique in that underground mines produce over 95% of the n
23、ations coal. Because of the great depth and high rank of Chinas coals, underground coal mines have higher methane emissions than surface mines. There are currently 108 Coal Mining Administrations (CMAs) in China, which manage more than 650 mines. These state-owned mines are responsible for most of C
24、hinas methane emissions, but there are numerous gassy local, township, and private mines that cumulatively produce over one-half of Chinas coal. However, these non-states owned mines are not gassy (International Energy Agency or IEA, 1994). 2.1.1 Methane recovery and use in China China has a long history of coal mine methane drainage, and the volume of methane drained has increased markedly during the past decade. Nationwide, coal mine methane drainage at state-run mines nearly doubled in 14 years, increasing from 294106 m3 in 1980 to more than 561106 m3 in 1994 .However, this is still
