煤炭地下气化碳减排技术研究进展与未来探索

Research progress and future study of carbon emission reduction for UCG

煤炭地下气化(UCG)与碳减排的相互融合,有望成为当前至碳中和到来之前过渡阶段的优秀绿色能源技术,甚至在未来更长的碳中和历史时期发挥重要作用。回顾研究历史与现状,UCG减排系统策略基本形成,可归纳为5种具体途径。其中,地下原位定向调控可减少CO_(2)释放产出并促进UCG提质增产,相关策略和途径可归纳为“碳调减(CRR)”。UCG-CO_(2)地下空间超临界气态封存研究成果相对较多,主要集中在封存介质、封存空间、封存能力等方面,少数研究讨论了封存机制。UCG-CO_(2)地下空间矿化封存不受地质体稳定性和封闭性苛刻条件的约束,潜在着固碳和转化产气的双重效果,但研究成果尚不多见。UCG-CO_(2)回注利用与封存的前期探索集中在煤层气增产和UCG合成气生产改善2个方面,近年来开创了UCG制氢尾气CO_(2)减排利用系列性探索。CRR作为一种主动减排策略,通过调节气化剂及其注入方式来定向调减UCG合成气中CO_(2)浓度,理论成果较多并且经过现场初步验证,有望成为集清洁能源生产与碳减排为一体的洁净煤实用技术。评述进展并分析短板,UCG碳减排科学技术研究已取得诸多实质性成果,也面临持续发展的挑战,未来探索似应聚焦在4个方向:一是立足可行,优先发展以UCG-CRR为重点的UCG-CO_(2)地下转化利用技术;二是聚焦短板,着力突破UCG减排-合成气提质协同机理和关键技术瓶颈;三是扎实推进,优先启动实施UCG-CRR先导试验和工程示范,探索步步取得实效;四是保障实现,探索建立由碳中和与碳管理战略、专项科技行动计划、专业人才培养构成的“三位一体”UCG减排政策支撑体系。

The integration of underground coal gasification(UCG)and carbon emission reduction is expected to become an excellent green energy technology during the transitional stage from the current to the arrival of carbon neutrality,and even play an important role in the longer history of carbon neutrality in the future.Looking back at the research history and current situation,the systematic strategy for UCG emission reduction has been basically formed,which can be summarized into five specific approaches.Among them,the targeted underground in-situ regulation can reduce the CO_(2) release and promote the quality and yield increase of UCG synthesis gas,and the relevant strategies and approaches can be summarized as the Carbon Regulation and Reduction(CRR).There are many research achievements on the supercritical gas storage of UCG-CO_(2) in underground space,mainly focusing on storage media,storage space,storage capacity,etc.,with some discussions for storage mechanisms.The mineralization and storage of UCG-CO_(2) in underground space are not constrained by the harsh conditions of geological stability and sealing,and there is a potential dual effect of both carbon sequestration and gas conversion,but there are not many research results yet.The previous exploration of UCG-CO_(2) reinjection,utilization and storage focuses on two aspects,such as enhancing coalbed methane production and improving the production of UCG synthesis gas,and a series of explorations have been initiated for the emission reduction and utilization of CO_(2) from the tail gas of UCG hydrogen production in recent years.The CRR,as an active emission reduction strategy,targetedly reduces the CO_(2) concentration in the UCG synthesis gas by adjusting the gasifying agent and its injection method,and there are many theoretical achievements and preliminary on-site verification,which are expected to become a practical clean coal technology that integrates clean energy production and carbon reduction.Reviewing the progress and analyzing the shortcomings,the scientific and technological research for UCG carbon emission reduction has made many substantial achievements,but also still faces some challenges of sustainable development,and the future study should focus on four aspects.One is to prioritize the development of UCG-CO_(2) underground conversion and utilization technology with a focus on the UCG-CRR based on feasibility.The second is to focus on the shortcomings and to strive for the breakthrough of the collaborative mechanism and key technological bottlenecks of both UCG emission reduction and synthesis gas quality improvement.The third is to make solid progess and promote the prior implementation of UCGCRR pilot tests and engineering demonstrations for the achievement of practical results step by step.The fourth is to ensure the implementation and establishment of the“trinity”policy support system for the UCG emission reduction consisting of carbon neutrality and management strategy,special science and technology action plans,and professional talent training.