Modeling, simulation, and techno-economic analysis of Lurgi gasification and BGL gasification for coal-to-SNG

Abstract Developing coal-to-SNG is an important way to deal with the shortage of natural gas supply. Lurgi gasification and BGL gasification are both adaptive for coal-to-SNG because of the rich content of CH 4 in raw gas after gasification. In this paper, the coal gasification unit and WGS units in the two coal-to-SNG processes are modeled and simulated. The numerical model of the two units are based on industrial data. Technical analysis shows that the Lurgi gasifier and BGL gasifier are consistent on the effect of steam to coal ratio and oxygen to coal ratio. As the increase of oxygen to coal ratio, the productivity firstly increases and then decreases. As the increase of steam to coal ratio, the “quality” of productivity decreases and the flowrate increases. The exergy loss of the Lurgi process is higher than that of the BGL process. So is that of the Lurgi gasification unit. Economic analysis shows that the investment for the Lurgi gasification unit is 5.9 × 10 7  USD more than that of the BGL gasification unit. Investment of the WGS unit in the Lurgi process is 1.8 × 10 6  USD less than that in BGL process. The income from steam generated in the WGS unit in the Lurgi process is higher than that in the BGL process. However, production cost for the Lurgi process is 88 USD while producing 1000 N m 3 effective gases, much higher than the cost for the BGL process, 50 USD.

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