Design and optimization of Kemira-Leonard process for formic acid production

Abstract Formic acid (FA) is a chemical with numerous industrial applications. Available literature including patents on FA processes are limited and do not provide sufficient information for process simulation. In the present study, a conventional FA process, known as the Kemira-Leonard (KL) process, for producing 98 wt% FA is developed and simulated using Aspen Plus V9. Then, heat integration and optimization of the process for two objectives (namely, minimization of total capital cost and annual utility cost) are performed. Finally, further improvement of the optimized process via vapor recompression (VR) is investigated. Bi-objective optimization provides many Pareto-optimal solutions for selection. Total annual cost (TAC) of the chosen optimized KL process without VR is found to be $19,887,834 (=0.724 USD/kg of FA produced), with total capital cost of $18,476,733. Addition of VR brings savings of $1,560,427 in annual utility cost, with an additional investment of $2,517,191 for the compressor and new heat exchangers; overall, this leads to TAC reduction of $1,035,748 (by 5.2%). Unit TAC after VR addition is 0.686 $/kg of FA produced.