On the economics of methanol production from natural gas

Methanol is rated among the top chemical commodities worldwide. Its production via indirect synthesis routes from natural gas is energy intensive and costly regarding the investment and operation. This study addresses the economics of methanol synthesis routes with different reforming technologies. Processes with steam reforming, autothermal reforming, and dry methane reforming are considered for medium capacities below 3000 metric tons per day. The exergetic efficiency of these processes is 34.8%, 56.9% and 39.8%, respectively. Furthermore, combined methane reforming, two-step reforming and a parallel configuration of steam - and dry methane reforming are discussed. Their exergetic efficiency is 48.6%, 57.2% and 46.3%, respectively. The processes with endothermic reforming technology inherently feature a co-production of electricity for high efficiency. The results from an economic case study are reported. Approximately 60-70% of the investment is required for the reforming unit. The fuel cost has a contribution of 50-60% in the specific product cost. Depending on the process, the payback period is 2 to 10 years. The economic uncertainties are addressed by conducting sensitivity analyses. An exergoeconomic analysis is used to calculate the levelized cost of methanol and electricity. The two-step reforming process constitutes the most attractive design from an exergoeconomic point of view, having the lowest levelized cost of methanol and electricity production among all processes. Finally, the plants are assessed by comparing the levelized cost of methanol with the range of historical methanol prices in Europe and North America. A low natural gas price makes an operation economically viable in both continents.