Design and optimization of small-scale methanol production from sour natural gas by integrating reforming with hydrogenation

This paper presents the design and simulation-based optimization of a small-scale sour natural gas to methanol process from the view of maximizing the operating profit during operation. It fully integrates steam reforming and CO/CO2 hydrogenation technologies, by which CH4 and CO2 in feeding gas are efficiently converted into methanol without considering CO/H-2 shift and CO2 removal. In order to obtain the true performances and potential advantages, a simultaneous multi-variable optimization strategy with multi-start procedure is performed by using built-in sequential quadratic programming algorithm. Besides, four cases studies that correspond to distinct levels of CO2 content are compared to investigate the effects of gas quality on the techno-economic performances. The optimization results show the proposed process has both economic and environmental benefits as it helps to achieve the valorization and carbon footprint reduction of CO2-rich natural gas resources. In particular, the feeding gas with 20 mol% CO2 concentration is beneficial for improving the operating profit of the process. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.