Techno-economic analysis of methanol synthesis from syngas derived from steam reforming of crude glycerol

Abstract

Due to the large amount of crude glycerol produced as a by-product by the biodiesel industry, alternative technologies for converting glycerol to value-added fuels such as syngas have been proposed. By employing four main processes, the syngas could further be used to produce methanol. The first process is steam reforming (STR) where the crude glycerol is converted into syngas. The next step is a three-unit pressure swing adsorption (PSA) system which is employed to condition the syngas into the required stoichiometric ratio. The final two process are the methanol synthesis and methanol purification processes. The effects of STR temperature, steam-to-glycerol ratio (SGR), methanol synthesis temperature and pressure were all investigated. The results obtained shows that 0.29 kgMeOH/kgCG can be obtained through this process at STR of 650 ℃, SGR of 9, and methanol synthesis temperature and pressure of 250 ℃ and 80 bar respectively. In addition, a methanol production plant capacity of 6.8 tonnes/hr of crude glycerol feed for a 20-year plant life was investigated. The result from the economic analysis carried out shows that production of methanol from glycerol is economically feasible with net present value (NPV), return on investment, (ROI), discounted payback period (DPBP) and net production cost (NPC) of $74.2 million, 17%, 4.59 years, and 85₵/kgMeOH respectively. The sensitivity analysis results show that the revenue from sales of methanol and byproducts (hydrogen and methane), the manufacturing cost, the cost of raw materials, as well as fixed capital investment (FCI) were the most sensitive economic parameters.