煤层瓦斯利用技术的现状和发展趋势开题报告

1. 研究目的与意义（文献综述包含参考文献）

A biological and structural change of the initial organic material generated coal deposits over thousands of years. This technique, known as coalification, creates huge amounts of by-product gasses that increase with mining rank, with anthracite producing the most around 27,000 ft3/t of gas only. During coalification procedure, the majority of such hydrocarbons go to the atmosphere, but a minor fraction is preserved in coal. The quantity of fuel preserved in coal is determined by several factors, including coal rank, burial depth, the surrounding roof and floors to the mine shaft, geological irregularities, geological forces, and the temperature at the completion of the coalification cycle. In general, the more the mining rank and the deeper the sedimentary layer, the higher the gas concentration of coal. Coal seam gas content ranges from such a couple ft3/t to 800 ft/ton at depths up to 3000 ft. Most gasses come from coal deposits, which serve as both a supply and a storage.Hydrocarbons build up the majority of methane in coal, accounting for 8095 percent of the entire gas flow rate. Hydrocarbons, methane, propane, CO2, hydrogen, dioxide, and nitrogen make up the balance. When subjected to ventilation system in such a mining, all coal seams begin to oxidize and produce carbon monoxide and sulfur oxides. Gasoline machinery for mining areas produces Sulphur dioxide pollutants.Mineral deposits (those which are too thick, excessively thin, or lack the inner consistency to be profitably produced with current technology) may have the ability to store CO2. Many power stations are close to coal seams, lowering transportation expenses. Carbon dioxide absorption in coal deposits can be most expense technique of safely storing CO2 from the atmosphere in an absorption tower that is intended to last for geologically long periods of time. Furthermore, because mineral deposits have a significant surface to volume ratio, they can store up to 7 times the volume of fuel as other natural reservoirs. The global CO2 storage potential is estimated to be 150 Gt.CO2 binds more readily into coals than CH4, which would be naturally produced in coal seams. More put it into another aspect, coal has a 213 times greater affinity for co 2 than methane. Adsorbent trapping is the feature that allows CO2 to be stored in coal deposits. Vacuum distillation and depressurization (coalbed gas extraction, or CBM) or infusion with N2 is the most common methods for recovering greenhouse gasses in coal seams (N2-ECBM). But, there is still a large quantity of gas contained in lignite that can be produced by CO2. Improved coalbed methane extraction is the method of infusing and retaining CO2 in mineral coal deposits to improve methane production.

2. 研究的基本内容、问题解决措施及方案

1.1 Research Content(研究内容)This study aims to discuss the gas drainage methods and technological systems across China in compliance with specific geologic circumstances. In establishing a general theory of CBM in China, a required procedure of CBM exploration, and a systems approach of exploitation in complies with the characteristics of coal layers in China, research needs to be conducted to investigate the dispersion, uptake, and adsorptive characteristics of CBM with in ground, as well as theories regarding comprehensive illustrations of coal reservoir layers.Because of the high demand for coal, many underground coal mines are being depleted on a daily basis. Furthermore, if the depth of coal has increased , many safety precautions taken in coal seams have been increasingly reduced in the development of deep hole practice, while the problems of coal operations has continued to increase. AS a result, even as situation demands, future state for well safety precautions has emerged. CBM has massive reserves as an unexpected energy resources and it can substitute to China's gas supply shortages. As a result, CBM mining and utilization are critical to an economic and ecological conservation. When coal mining depths rise, the technique for extracting CBM utilised in shallower coal deposits cannot be immediately adapted to deep coal seams, necessitating the use of specialized methods and techniques. As a result, understanding the present state of mining and CBM growth in China is critical for the safe operation of mining areas.1.2 Critical problems(关键问题)Simultaneously, continuous innovation of relevant techniques should be promoted; implementing this intensive of methane control technologies responding to different conditions should be built. It will enhance coal bed mine gas control and the CBM mining and usage sector in China.Ground CBM extraction and subterranean gas draining are the two main methods for gas utilization in China at the moment. Underground gas drainage is critical for preventing gas explosions and ensuring safe mining. On the one hand, underground gas draining has indeed been found to be lacking in boldness or far vision due to mine excavating and coal extraction arrangements, and as a result, it is still primarily used to deal with these situations in order to maintain safe mining. Furthermore, the limitations imposed by technological infrastructure have resulted in gas drainage being inefficient and ineffective.Different modes of techniques are used in china for the production of coal seam gas. These modes are as following.