Design and Control of Acetaldehyde Production Process

Abstract

This paper discusses the steady state and dynamic simulations of acetaldehyde production process by using Aspen Plus and Aspen Dynamics. The model developed in the present study is the modification of the process developed by Eastman Chemical Company of U.S. Patent 6,121,498. The proposed design consists of a FEHE (feed effluent heat exchanger), reactor, absorption column, compressors and two distillation columns. Acetic acid reacts with hydrogen and gives acetaldehyde as main product and ethanol, ethyl acetate, acetone, and water as byproducts. The paper is divided into two stages. In the first stage, the entire process plant is developed for steady-state simulations and in the second stage, dynamic simulations are performed by providing decentralized controllers for the entire plant. Tray temperature control loop and composition control loop are designed to maintain final product purity. Results of dynamic simulation are analyzed for different process conditions. The proposed plant with control structure performs very well in rejecting various disturbances while maintaining the acetaldehyde product purity at 95.17 mol%, with a settling time of less than 9 h.