Techno-economic evaluation of simultaneous methanol and hydrogen production via autothermal reforming of natural gas

The demand for clean energy and efficient resource utilization needs the existing processes to be modified for optimal performance. The study investigates the production of high purity methanol through the autothermal reforming (ATR) process technology. Two cases were developed: Case I, where only methanol is produced from syngas via natural gas reforming, and Case II, where co-production of high-purity hydrogen and methanol was made possible. In Case II, the adjustment of the module number was used to optimize the conversion in the methanol synthesis reactor by manipulating the recycle split ratio. Results show that by adjusting the split ratio, approximately 21.12 t/h of high purity H2 can be produced along with 101.99 t/h of AA-grade methanol. However, the co-production of hydrogen is made at the expense of decreased methanol production. The proposed co-production route offers process flexibility to produce hydrogen and methanol as per customer demand. The study also examined the process efficiency and found that the proposed Case II consumes less energy in the methanol synthesis and methanol purification sections compared to Case I. The process efficiency is 55 % and 57.5 % for Case I and Case II respectively, on the other hand, Case I requires 13.05 GJ, while Case II requires 17.55 GJ for fuel production. A sensitivity analysis has been performed to study the effect of varying split ratio on the module number, and the results show that as the split ratio increases, methanol production decreases, which reduces the total energy requirement of the process. Finally, a detailed economic comparison has been conducted to ascertain the production of dual fuel versus single fuel, and the results show that Case II is more profitable than Case I over the project lifetime.