Iranian Journal of Chemical Engineering (IJChE)

Abstract The synthesis of methanol is a key industrial process, but its performance is constrained by equilibrium conversion, heat dissipation, and energy inefficiencies. This study simulated the multi-bed adiabatic reactor of the Methanol and Derivatives Complex (CP1Z) located in Arzew, Algeria by Aspen HYSYS. Two reactor models were evaluated: the Equilibrium Reactor (ER), based on Gibbs free energy minimization, and the Plug Flow Reactor (PFR), which incorporates detailed kinetics. Both models were validated against industrial plant data to assess predictive accuracy. The ER model demonstrated better agreement with industrial data, particularly for the concentration of methanol (0.36% deviation), and was therefore selected for process improvement studies. Two modifications were introduced. First, recycling unreacted syngas increased the production of methanol from 613 kmol/h to 1800 kmol/h, a 193% improvement. Second, replacing air coolers with a heat exchanger–steam turbine system enabled the recovery of 1100 kW of electricity without reducing the methanol yield. When both modifications were applied simultaneously, the methanol output rose to 1917 kmol/h (+213%), and electricity generation increased to 1763 kW. The integration of the recycling of syngas and waste heat recovery substantially enhances the conversion efficiency, energy utilization, and sustainability of the production of methanol. Since these modifications require no major hardware changes, they offer a practical and scalable strategy for improving the technical, economic, and environmental performance of existing industrial methanol plants. 

Abstract In this paper, a heterogeneous one-dimensional model for simulation of cascade methanol reactor has been developed, while the various percent of CO was injected to these reactors. In the cascade reactor configuration, a system with two-catalyst bed instead of one single catalyst bed is applied for methanol synthesis. In the first catalyst bed, the synthesis gas is partly converted to methanol in a water-cooled reactor. In the second bed, which is a gas-cooled reactor, the reaction heat is used to preheat the feed gas to the first bed. In this study, the various percent CO injections of feed entrance (1% and 2%) to different reactors (first and second reactor) of conventional dual type methanol reactor have been considered. The simulation results represent 5.127% and 4.158% enhancement in the yield of methanol production in comparison with conventional dual type methanol reactor (CDMR) and membrane dual type methanol reactor (MDMR) respectively, while 2% CO was injected to the first reactor. Also, by CO injection to the feed, water produced during methanol synthesis via CO2 hydrogenation which accelerates the catalyst deactivation and reduces methanol
production rate, is reduced greatly.