Experimental forward and reverse in situ combustion gasification of lignite with production of hydrogen-rich syngas

Abstract

Abstract This research focused on the feasibility of applying the forward and reverse combustion approach to the in situ gasification of lignite with the production of hydrogen-rich syngas (H2 and CO). The so-called forward combustion gasification (FCG) and reverse combustion gasification (RCG) approach in which oxygen and steam are simultaneously fed to the simulated system of underground coal gasification (UCG) was studied. A simulated system of UCG was designed and established. The underground conditions of the coal seam and strata were simulated in the system. The combustion gasification of lignite has been carried out experimentally for almost 6.5 days. The average effective content (H2 + CO) of syngas during the FCG phase was 62.31 % and the maximum content was 70.92 %. For the RCG phase the corresponding figures are 61.33 % and 67.91 %. Thus, the feasibility of using RCG way for UCG has been demonstrated. The temperature profiles have been provided by using of 85 thermocouples during the model experiment, which portrayed the several nephograms of thermal data in the gasifier were of significance for the prospective gasification processes.

Keywords

• Underground coal gasification
• Reverse combustion gasification
• Forward combustion gasification
• Hydrogen-rich
• Syngas