山西重点煤矿区瓦斯梯级利用关键技术与工程示范

Key technology and engineering demonstration for cascade utilization of gas in key coal mining areas of Shanxi Province, China

  • 摘要: 山西重点煤矿区包括晋城、阳泉、西山、汾西、潞安等矿区,是“十三五”国家科技重大专项“山西重点煤矿区煤层气与煤炭协调开发示范工程”的主要实施地点。依托国家科技重大专项项目资助,研发了煤矿瓦斯梯级利用系列技术,并进行工程示范,引导山西重点煤矿区瓦斯抽采量与利用量由2015年的60.2亿m3和22.3亿m3提高至2020年的64.03亿m3和28.94亿m3,利用率由37%提升至45%,在保障煤矿安全开采的前提下极大地助力碳达峰碳中和目标的实现。梯级利用主要是根据甲烷浓度高低分别加以综合利用,对于甲烷体积分数≥30%的高浓度煤矿瓦斯,可以进行集输后按照效益最大化原则进行发电、民用、工业利用等。对于甲烷体积分数<30%的低浓度瓦斯,依据不同浓度瓦斯利用技术差异性及适应性,将低浓度瓦斯的浓度利用区间划分为4级:甲烷体积分数介于16%~30%的低浓度瓦斯可采用变压吸附技术,提纯后可使甲烷体积分数达到30%以上满足后续民用及集输等要求,该项技术已在晋城矿区成庄矿建设了处理能力为12 000 m3/h的示范装置;在有高浓度煤矿瓦斯的矿区也可利用掺混技术直接将甲烷体积分数提高至30%以上进行集输利用。甲烷体积分数介于9%~16%的低浓度瓦斯可采用就地发电技术,转化为电能后可自用或上网,该技术已在晋城矿区赵庄矿、胡底矿、长平矿等建设了示范装置。甲烷体积分数介于6%~9%的低浓度瓦斯可采用直燃技术,转化为热能后进行电、热、冷三联供,该技术已在成庄矿建设了示范装置。甲烷体积分数介于1%~6%的低浓度瓦斯可采用蓄热氧化与掺混技术,同样转化为热能后进行电、热、冷三联供,该技术已在华阳新材料科技集团有限公司(原阳泉煤业集团)一矿及五矿建设了示范装置。低浓度瓦斯梯级利用技术虽然在山西重点煤矿区进行了成功示范,但目前仍存在很多技术经济难题,在碳达峰碳中和目标下,亟需进行持续攻关并快速提高利用率。

     

    Abstract: The key coal mining areas of Shanxi Province, including Jincheng, Yangquan, Xishan, Fenxi and Lu’an, are the main implementation sites of the “13th Five-Year” national science and technology major project “Demonstration Project of Coordinated Development of Coalbed Methane and Coal in Key Coal Mining Areas of Shanxi”. Relying on the high-end platform of the national science and technology major project, a series of technologies for cascade utilization of coal mine gas have been developed and demonstrated to guide the enhancement of gas drainage and utilization from 6.02 billion m3 and 2.23 billion m3 in 2015 to 6.403 billion m3 and 2.894 billion m3 in 2020 respectively, as well as the increasing of utilization rate from 37% to 45%, thereby greatly assisting to the realization of the goals of coal peaking and coal neutrality under the precondition of ensuring the safe mining of coal mine. Cascade utilization is mainly based on the comprehensive utilization of methane concentration of gas. Specifically, the high-concentration coal mine gas with the volume fraction of methane above 30% (including) can be used for power generation, civil and industrial utilization according to the principle of maximizing the benefits after gathering. For the low-concentration gas with the volume fraction of methane less than 30%, the utilization interval is divided into four levels according to the difference and adaptability of different gas utilization technologies. The low-concentration gas with the volume fraction of methane of 16%‒30% could be purified with the pressure swing adsorption technology, so that the volume fraction of methane reaches 30% or more, satisfying the subsequent requirements of civil utilization and gathering. In terms of this technology, a demonstration device with a processing capacity of 12 000 m³/h has been built in Chengzhuang Mine of Jincheng mining area. In the mining area with high-concentration coal mine gas, the mixing technology can also be used to directly increase the concentration of methane to more than 30% for gathering. The low-concentration gas with the volume fraction of methane ranging from 9% to 16% can be converted into electricity locally for local-use or access to the grid, for which the demonstration devices have been constructed in Zhaozhuang Coal Mine, Hudi Coal Mine and Changping Coal Mine in Jincheng mining area. The low-concentration gas with the volume fraction of methane within 6%‒9% can be converted into heat by direct combustion technology for the combined supply of electricity, heat and cold, for which the demonstration device has been built in Chengzhuang Coal Mine. In addition, the low-concentration gas with the volume fraction of gas in the range of 1% to 6% can be converted into heat by regenerative oxidation technology for the combined supply of electricity, heat and cold, for which the demonstration device is built in No. 1 Coal Mine and No. 5 Coal Mine of Huayang New Material Technology Group Co., Ltd. (the former Yangquan Coal Industry Group). The cascade utilization technology of low-concentration gas, successfully demonstrated in the key mining areas of Shanxi, still has many technical and economic challenges at present. Therefore, it is urgent to perform the research continuously and rapidly improve the utilization rate under the goal of coal peaking and coal neutrality.

     

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