Proposal and investigation of CO2 capture from fired heater flue gases to increase methanol production: A case study

In a petrochemical complex in Iran, for production of 209575 kg of MeOH/h, 154,712 kg/h of flue gas with a CO2 concentration of 10.74 mol% enter the atmosphere through a fired heater. The target of this study is to investigate the effect of using post-combustion CO2 capture technology to reduce carbon dioxide emissions and use it to increase methanol production. In order to, the proposed process was simulated and effect of three different solvents, including piperazine (PZ) 30 wt%, monoethanolamine (MEA) 30 wt%, and a blend of MEA 20 wt %+ PZ 10 wt % were investigated. This study investigated solvent regeneration energy, CO2 absorption rate, energy efficiency, and exergy efficiency of stripper column. Simulation results showed PZ with 93% energy efficiency, 55.45% exergy efficiency of stripper column, CO2 emission intensity equal to 0.01 tCO2/tMeOH and lowest solvent regeneration energy equal to 2.6 GJreb/tCO2 has better performance than the other two solvents. Also, the simulation results showed that blending CO2 output from PZ solvent with syngas increases methanol production by 7.8%. The techno-economic analysis also indicated proposed process is more profitable than original process. [Display omitted] •Post-combustion CO2 capture process was used to reduce carbon dioxide emissions.•Methanol production increased 7.8% by blending CO2 from PZ solvent with syngas.•The effect of PZ, MEA, and blend of them on CO2 capture was investigated.•The energy efficiency and stripper column exergy efficiency of piperazine solvent are 93% and 55.45%, respectively.•The MEA solvent with 94.25% absorption and CO2 emission intensity 0.0086 tCO2/tMeOH was superior to two other solvents.