Methanol Synthesis from Syngas: a Process Simulation
Ramesh Timsina, Rajan K. Thapa, Britt M. E. Moldestad, Marianne S. Eikeland
Abstract
Methanol is one of the major candidates to take over the petroleum based liquid transportation fuel. Methanol synthesis from syngas is proposed in this paper. The Aspen Plus simulation software was used to simulate the conversion process from syngas into methanol. A CSTR reactor with defined reaction kinetics was taken at 40 bar and 270°C to simulate the methanol synthesis. Hydrogen recycles gave an increase of 50.4% in the production of methanol as compared to the results without a H₂ recycle stream. The conversion of CO, CO₂ and H₂ are 50.4%, 99.8% and 100% respectively for the case with the H₂ recycle. Considering an operation of 8600 hr/year, the annual mass production of methanol is equal to 96492 tonnes for a feed rate of 154972 t/year. A distillation column is used to separate the methanol from water. Simulations were performed to calculate the minimum number of stages for the different recovery ratios of methanol in distillate and the required molar reflux ratio versus the purity of methanol in the distillate. The column temperature and the composition profile were analyzed for the column. The model provides the insights of the methanol synthesis plants for a specific quality and the quantity of methanol production.