【背景】水力压裂是煤层气商业化开发中常用的增产技术,胍胶已被广泛用作水力压裂的增稠剂。然而,在煤储层低温条件下,常规化学破胶方法存在破胶不充分、残渣含量高等问题,易引发储层伤害并降低煤层气井的开采效率。【方法】利用煤层本...【背景】水力压裂是煤层气商业化开发中常用的增产技术,胍胶已被广泛用作水力压裂的增稠剂。然而,在煤储层低温条件下,常规化学破胶方法存在破胶不充分、残渣含量高等问题,易引发储层伤害并降低煤层气井的开采效率。【方法】利用煤层本源菌作为功能菌种,开展微生物破胶实验,分析煤层本源菌对胍胶的生物降解特性并确定群落中具有胍胶降解能力的功能微生物。【结果和结论】煤层本源菌可以彻底降解胍胶,满足黏度≤5 mPa·s的压裂液破胶要求,同时降低残渣含量及其粒径分布水平,可有效减轻胍胶压裂液破胶过程产生的不溶性残留物对煤储层的潜在伤害;胍胶主要被煤层本源菌水解为可溶性多糖,从而降低黏度并实现破胶;微生物群落结构分析表明,拟杆菌门(Bacteroidota)和螺旋体门(Spirochaetota)在胍胶降解中发挥了主要作用;通过PICRUSt2(Phylogenetic Investigation of Communities by Reconstruction of Unobserved States 2)功能预测发现,胍胶降解主要依赖于α-半乳糖苷酶(EC:3.2.1.22)、β-甘露糖苷酶(EC:3.2.1.25)和β-甘露聚糖酶(EC:3.2.1.78)的协同作用,其中β-甘露聚糖酶的基因丰度增幅最大,表明其是胍胶破胶的主要功能酶。此外,环境因素直接影响胍胶的破胶效率,煤层本源菌在45℃、pH=6.0降解效率最高;高盐度抑制胍胶降解,但在40 g/L盐度条件下,煤层本源菌仍具有破胶能力。研究成果不仅揭示了煤层本源菌对胍胶的降解机制,还确定了环境因素对煤层本源菌生物破胶的影响规律,为煤层本源菌生物破胶技术在煤层气开采中的应用提供了理论依据。展开更多
Coal serves not only as a crucial energy resource but also as a significant reservoir of critical metal elements,including Lithium(Li),Gallium(Ga),Germanium(Ge),and rare earth elements(REE).This paper provides a syste...Coal serves not only as a crucial energy resource but also as a significant reservoir of critical metal elements,including Lithium(Li),Gallium(Ga),Germanium(Ge),and rare earth elements(REE).This paper provides a systematic review of the enrichment characteristics,occurrence modes,and comprehensive utilization potential of these critical metals in coal.Globally,the distribution of these metal resources exhibits significant regional heterogeneity.While the concentration in most coals falls below industrial cut-off grades,anomalous enrichment in specific coal basins results in Li,Ga,Ge,and REE concentrations far exceeding global averages,highlighting their considerable potential as unconventional metal deposits.The occurrence modes of these metals are diverse:Li is primarily hosted in mineral phases;Ga exists in inorganic,organic,and complex forms;Ge shows a strong association with organic matter;and REE are mainly present in adsorbed/isomorphic forms within clay minerals,while also displaying organic affinity.Direct extraction of metals from raw coal is often cost-prohibitive;effective recovery is therefore more feasible when integrated with coal processing.Metals are further enriched in solid wastes such as coal gangue,fly ash,and bottom ash,from which recovery is more economically and technically viable.Current comprehensive utilization primarily employs integrated mineral processing-hydrometallurgy approaches.Future research should focus on elucidating the precise occurrence forms of metals in coal and solid wastes,optimizing pre-treatment methods,and selecting effective activators and leachants.Advancing the synergistic extraction and green recovery of multiple associated resources from coal and its by-products is essential for achieving high-value,comprehensive utilization of coal-based resources.展开更多
文摘【背景】水力压裂是煤层气商业化开发中常用的增产技术,胍胶已被广泛用作水力压裂的增稠剂。然而,在煤储层低温条件下,常规化学破胶方法存在破胶不充分、残渣含量高等问题,易引发储层伤害并降低煤层气井的开采效率。【方法】利用煤层本源菌作为功能菌种,开展微生物破胶实验,分析煤层本源菌对胍胶的生物降解特性并确定群落中具有胍胶降解能力的功能微生物。【结果和结论】煤层本源菌可以彻底降解胍胶,满足黏度≤5 mPa·s的压裂液破胶要求,同时降低残渣含量及其粒径分布水平,可有效减轻胍胶压裂液破胶过程产生的不溶性残留物对煤储层的潜在伤害;胍胶主要被煤层本源菌水解为可溶性多糖,从而降低黏度并实现破胶;微生物群落结构分析表明,拟杆菌门(Bacteroidota)和螺旋体门(Spirochaetota)在胍胶降解中发挥了主要作用;通过PICRUSt2(Phylogenetic Investigation of Communities by Reconstruction of Unobserved States 2)功能预测发现,胍胶降解主要依赖于α-半乳糖苷酶(EC:3.2.1.22)、β-甘露糖苷酶(EC:3.2.1.25)和β-甘露聚糖酶(EC:3.2.1.78)的协同作用,其中β-甘露聚糖酶的基因丰度增幅最大,表明其是胍胶破胶的主要功能酶。此外,环境因素直接影响胍胶的破胶效率,煤层本源菌在45℃、pH=6.0降解效率最高;高盐度抑制胍胶降解,但在40 g/L盐度条件下,煤层本源菌仍具有破胶能力。研究成果不仅揭示了煤层本源菌对胍胶的降解机制,还确定了环境因素对煤层本源菌生物破胶的影响规律,为煤层本源菌生物破胶技术在煤层气开采中的应用提供了理论依据。
基金supported by the Key Support Project of Regional Innovation and Development Joint Fund of the National Natural Science Foundation of China(No.U24A2095).
文摘Coal serves not only as a crucial energy resource but also as a significant reservoir of critical metal elements,including Lithium(Li),Gallium(Ga),Germanium(Ge),and rare earth elements(REE).This paper provides a systematic review of the enrichment characteristics,occurrence modes,and comprehensive utilization potential of these critical metals in coal.Globally,the distribution of these metal resources exhibits significant regional heterogeneity.While the concentration in most coals falls below industrial cut-off grades,anomalous enrichment in specific coal basins results in Li,Ga,Ge,and REE concentrations far exceeding global averages,highlighting their considerable potential as unconventional metal deposits.The occurrence modes of these metals are diverse:Li is primarily hosted in mineral phases;Ga exists in inorganic,organic,and complex forms;Ge shows a strong association with organic matter;and REE are mainly present in adsorbed/isomorphic forms within clay minerals,while also displaying organic affinity.Direct extraction of metals from raw coal is often cost-prohibitive;effective recovery is therefore more feasible when integrated with coal processing.Metals are further enriched in solid wastes such as coal gangue,fly ash,and bottom ash,from which recovery is more economically and technically viable.Current comprehensive utilization primarily employs integrated mineral processing-hydrometallurgy approaches.Future research should focus on elucidating the precise occurrence forms of metals in coal and solid wastes,optimizing pre-treatment methods,and selecting effective activators and leachants.Advancing the synergistic extraction and green recovery of multiple associated resources from coal and its by-products is essential for achieving high-value,comprehensive utilization of coal-based resources.
