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不同CO₂压力下黄铁矿与煤制气耦合机制研究

夏大平1,2,3, 廖佳佳1, 王心义1,2,3, 李赛赛4, 顾朋涛4, 袁筱莹1, 简阔5

1.河南理工大学 资源环境学院，河南 焦作 454000 2.河南理工大学 煤炭安全生产与清洁高效利用省部共建协同创新中心，河南 焦作 454000 3.河南理工大学 矿业研究院，河南 焦作 454000 4.河南理工大学 能源科学与工程学院，河南 焦作  454000 5.太原科技大学 能源与材料工程学院，山西 晋城  048011

摘要:  目的  为了研究不同CO2压力下黄铁矿与煤制气的耦合机制， 方法  利用压力为1，3，5 MPa的高压罐进行煤和黄铁矿厌氧发酵产气试验。 结果 结果表明：（1）压力1 MPa时产气量较好，最终产气量为1.26 mmol/g；压力增加，罐中产气量减少，压力5 MPa时产气量仅0.02 mmol/g。（2）随着压力增加，水溶液中HCO^-₃质量浓度和氧化还原电位（Eh）逐渐上升，pH逐渐下降，5 MPa试验组反应末期pH最低，为4.02，1 MPa压力罐内总铁有消耗，波动较大；反应前期，3 MPa和5 MPa压力罐中总铁质量浓度持续增加，说明反应前期3 MPa和5 MPa压力下黄铁矿溶解量增加较多；（3）高压条件下，化学需氧量（chemical oxygen deman，COD）和短链脂肪酸浓度水平的显著减少反映了厌氧发酵程度的减弱和黄铁矿酸化程度的增强；；（4）压力增加，功能菌种丰度和多样性降低，硫杆菌属逐渐处于优势地位，厌氧发酵过程基本停滞。 结论  适宜的CO2压力条件可促进煤储层条件下的微生物生长代谢，同时添加黄铁矿发生氧化产生的铁离子，可促进菌群酶活，使煤生物产气反应顺利进行。研究结果可为原位条件富集营养液注入后的产气机制研究提供理论支撑。

关键词:CO压力;煤生物产气;黄铁矿;总铁;酸化程度

doi:10.16186/j.cnki.1673-9787.2023020065

基金项目:国家自然科学基金资助项目（42230804，42172199，42102218）；河南省创新型科技人才队伍建设工程项目（CXTD2016053）；河南省优秀青年科学基金资助项目（202300410168）；中国石油集团公司“十四五”前瞻性基础性技术攻关课题（2021DJ2302）

收稿日期:2023/02/22

修回日期:2023/04/06

出版日期:2024/05/15

Study on the coupling mechanism between pyrite and coal gasification under different CO2 pressure

XIA Daping1,2,3, LIAO Jiajia1, WANG Xinyi1,2,3, LI Saisai4, GU Pengtao4, YUAN Xiaoying1, JIAN Kuo5

1.School of Resources & Environment，Henan Polytechnic University，Jiaozuo  454000，Henan，China 2.Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization，Jiaozuo  454000，Henan，China 3.Mining Research Institute，Henan Polytechnic University，Jiaozuo  454000，Henan，China 4.School of Energy Science and Engineering，Henan Polytechnic University，Jiaozuo  454000，Henan，China 5.College of Energy and Materials Engineering，Taiyuan University of Science and Technology，Jincheng  048011，Shanxi，China

Abstract:  Objectives  To investigate  the coupling mechanism between pyrite and coal gasfication under different CO2 pressure，   Methods  anaerobic fermentation gas production experiments were carried out using high-pressure tanks with third-order pressures of 1，3 and 5 MPa for coal and pyrite，respectively.   Results  （1）The gas production was better at a pressure of 1 MPa，with a final gas production value of 1.26 mmol/g.As the pressure increased，the gas production in the tank decreased，and it was only 0.02 mmol/g at the 5 MPa.（2）With the increase of pressure，the mass concentration of HCO^-₃ and Eh in the aqueous solution gradually increased，while the pH kept decreasing，with the lowest value appeared at the end of the reaction in the 5 MPa experimental group，which was 4.02.The total Fe in the 1 MPa tank had a depletion and fluctuation，while the total Fe concentration in the 3 MPa and 5 MPa pressure tanks increased continuously in the pre-reaction period，indicating that the amount of dissolved pyrite increased more at the pressure of 3 MPa and 5 MPa.（3）Under high-pressure conditions，the significant decrease in chemical oxygen demand（COD） and short-chain fatty acid concentrations reflects a weakened anaerobic fermentation and an enhanced degree of pyrite acidification.（4）The high throughput results indicated that the increase in pressure led to a decrease in the abundance and strain diversity of the functional species，with Thiobacillus spp. gradually became dominant，and this brought the anaerobic fermentation process to a basic standstill.   Conclusions  Suitable CO2 pressure conditions can promote the growth and metabolism of microorganisms under coal reservoir conditions，while the addition of pyrite undergoes oxidation to produce iron ions，which can promote the enzymatic activity of the bacterial colony and make the biogenic gas production reaction of coal proceed smoothly.The study could provide good theoretical support for an in-depth understanding of the gas production mechanism after nutrient enrichment injection in situ conditions.  

Key words:COpressure;coal biogenic gas production;pyrite;total Fe;degree of acidification