System-Level Analysis of Methanol Production from Shale GasIntegrated with Multibed-BTX Production

초록

The production of benzene, toluene, and xylene (BTX) is anenergy-efficient subprocess that produces highly pure CH4from shale gas bycoaromatizing shale gas-derived C2H6and C3H8; this method is considered afeasible option for replacing conventional cryogenic distillation. Moreover, arationally designed proof-of-concept co-production of BTX and methanolproduction is proposed. Our proposed BTX production process from shale gasconsists of multiple beds, each of which undergoesfive sequential processes,including carburization, reaction, cooling, regeneration, and heating in acontinuous cyclic mode. Also, the switching time of the reaction/regenerationprocess is optimized withfixed-bed reactor experiments, and the general algebraicmodeling system was used to develop the corresponding nonlinear programming-optimized catalyst regeneration strategy. Our Mo/HZSM-5-based BTX production method enables continuous BTX production from shale gas and shows relatively high yield of BTX(10.0%) compared to conventional methane dehydroaromatization process (similar to 5%). Furthermore, the method leads to an increasedamount of produced CH4with a high BTX yield owing to the cracking of C2H6and C3H8, thereby resulting in increased methanolproduction. Most importantly, the technoeconomic analysis revealed that the estimated minimum selling price of methanolproduction is approximately 0.321 $/kg methanol for 24.4% improved methanol production, which is comparable to that obtainedwith the current most mature methanol production process. The proposed process also lower CO2emission compared to that of theconventional process. The results of this analysis support the feasibility of the integrated BTX and methanol production process forenergy-efficient shale gas conversion into high-value products

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