ASPEN Simulation of an Indirect Coal-Liquefaction Plant

摘要

The methanol synthesis, the Mobil methanol-to-gasoline (MTG) conversion, and the synthetic natural gas (SNG) upgrading steps in an indirect coal-liquefaction plant were simulated and analyzed using the Advanced System for Process Engineering (ASPEN). The plant, proposed to be built for the Tri-State Synfuels Company in Western Kentucky, converts 19,900,000 kg/d (21,900 ST/D) of coal to 3.31 x 10 exp 6 kg gasoline/day and 2.99 x 10 exp 6 kg liquefied petroleum gas/day. Closure of the simulation with the design mass balance was within 99.7% through the MTG processing step. Simulated estimates for the mass flow of crude methanol were only 0.2% less than those for the proposed design. A molar recycle-to-feed ratio of 4.5 yielded a crude methanol product stream similar to the design case. The purity of the crude methanol was calulated to be 98%, in comparison with the proposed design purity of 95%. The ASPEN simulation revealed the design case to have overestimated gasoline production by 16,400 kg/h (36,000 lb/h) or 11.8%, and underestimated wastewater production by 15,000 kg/h (33,000 lb/h) or 7.2%. The alkylation section of the MTG step and the methanation section of the SNG upgrading steps were only partially simulated due to limited process information. An overall energy balance indicated a net production of energy (4.9 GW or 17 x 10 exp 9 Btu/h) from the plant. Most (91%) of the energy comes from methanol synthesis. (ERA citation 07:049045)