Coal to Methanol Process Using Chemical Looping Gasification for Syngas Production and in Situ CO_2 Capture

摘要

Chemical Looping Gasification (CLG) technology has been developed for the efficient conversion of coal to syngas for efficient chemical and/or power generation. This CLG process uses an iron-based oxygen carrier (OC) in a co-current moving bed reactor to gasify coal without the need of molecular oxygen to perform the gasification reactions. The OC circulates between two reactors, a reducer and oxidizer, allowing for the continuous production of syngas and regeneration of the OC, respectively. In the case of methanol production, a specific syngas ratio of 2:1 hydrogen (H_2) and carbon monoxide (CO) is required. To reach this specific ratio, conventional processes use coal gasification methods that require energy and capital cost intensive air separation units (ASU). Compared to the current state of the art baseline carbon-capture case for a coal only feed to methanol production, the CLG process offers a more economical approach to utilizing coal for methanol production, providing 14% greater efficiency with ＞90% carbon capture, a lower methanol required selling price (RSP) by 21%, and lower capital costs by 28%. By using CLG process, a pure stream of CO_2 can be produced and sequestered economically, providing an incentive for combating the release of greenhouse gasses and global warming. This presentation will initially focus on the theoretical thermodynamic rationale and validating experimental results from bench and sub-pilot scale testing for using a co-current moving bed reducer and an optimized iron-based OC particle. The comprehensive techno-economic analysis results and sensitivity studies performed in collaboration with WorleyParsons on the CLG process for methanol production will be discussed.