Process Optimization of Coke Oven Gas to Methanol Based on the Downgrade of By-Product Steam

Abstract

In the coke oven gas to methanol (CTM) process, boiling water (above 200 °C) is generally used as the coolant in the methanol synthesis reactor, and thus, medium-pressure steam is generated as a by-product. In this paper, the influence of the coolant temperature on the CTM process is investigated from two aspects, which are the performance analyses of the reactor and the overall process and the energy integration of by-product steam. The results reveal that the coolant temperature plays a key role in the CTM process optimization. When the coolant temperature is reduced to 187 °C, though low-pressure steam is generated, the techno-economic performance of the whole process is greatly improved: the energy/exergy efficiency is increased by 4–9%, energy cost is saved by 37.1%, income is increased by 5.4 M$/year, and the CO 2 emission is reduced by 21.3%.