Enhanced transesterification reactive distillation for producing isopropanol: From kinetics, pilot-scale experiments, and process design to sustainability evaluation

Abstract

The demand for isopropyl alcohol (IPA) has increased significantly due to its excellent disinfection and sterilization effect. The production of IPA by isopropyl acetate (IPAC) with methanol (MeOH) transesterification is limited by chemical equilibrium, and there are three binary azeotropic mixtures in the system, which makes the production process more complex and energy consumption higher. Thus, the reaction distillation (RD) process is designed and developed for producing IPA more effectively and economically. The KRD001 as the commercial catalyst is utilized to build the kinetic reaction model, which supplemented the primary data of the chemical industry. The Pilot-scale RD experiments for producing IPA are explored to verify the feasibility of RD and the reliability of the model and to ensure the establishment of the follow-up process. The hybrid distillation process (RDC-HDC) of RD combining pressure-swing distillation (PSD) is designed and optimized based on the pressure sensitivity analysis and sequential iterative optimization algorithm on the minimum TAC under the 2,800 tons annual output of the factory. The thermal coupling processes (RDWC-HDC and RDWC-RDC) are explored to find energy-saving schemes. The RDWC-HDC process can reduce 20.46% in energy consumption, save 25.65% in total annual cost (TAC), and reduce annually the 1834.73 tons and 9557.13 $ in CO2 emissions, 55.20 tons and 20.59 $ in SO2 emissions and 27.60 tons, and 20.56 $ in NOx emissions in contrast with the RDC-HDC process, respectively. The exergy destruction elaborates that the RDWC-HDC process is positive for energy saving. The RDWC-HDC process is the most economical and attractive for producing IPA through the energy, economy, environment, and exergy (4E) analyses.