Comparison and techno-economic evaluation of process routes for lower olefin production via Fischer–Tropsch and methanol synthesis

Abstract

This paper describes the simulation and techno-economic evaluation of a carbon dioxide capture and utilization unit integrated in a cement plant with a capacity of 10,000 tons of CO2 per year. The aim is to utilize CO2 along with hydrogen to produce lower olefins (C2–C4), the feedstock for polyolefin production. In a first step, three process routes, namely a Fischer–Tropsch synthesis with steam cracker, a methanol synthesis with rWGS syngas production and a methanol synthesis with direct hydrogenation of CO2, latter two followed by a methanol-to-propylene unit, are simulated in ASPEN Plus V12.1®. Furthermore, the effect of a high- and a low-temperature electrolysis on key performance indicators are also considered in the evaluation. Additionally, an estimation of investment, operating and specific net production costs (NPCPR) of the different process routes is made. The evaluation is based on the comparison of calculated global efficiencies, specific energy consumption (SEC), NPCPr and yields of the lower olefine products (C2–C4). The power-to-lower olefin plant, consisting of an amine scrubber unit, a PEM electrolysis and a Fischer–Tropsch synthesis with downstream steam cracker proves to be the most efficient process route for polyolefin production, resulting in a global efficiency of 38.2 %, an SEC of 34.4 kWh/kg and an NPCPr of 14.92 EUR/kg of lower olefine product.