Sustainable Production of Maleic Anhydride: Minimizing By-Product Formation in Industrial Fixed-Bed Tubular Reactor

Abstract

The synthesis of maleic anhydride from n-butane in an industrial fixed-bed reactor is presented, with emphasis on reducing by-product formation. The modeling and simulation of an industrial fixed-bed reactor are also presented in this paper. The research was conducted using industrial process data collected from a fixed-bed reactor over a defined period, addressing challenges related to conversion, yield, selectivity, and minimization of acrylic acid formation. The numerical software package MATLAB was used for solving the system of mathematical model equations. By decreasing the molar flow of n-butane at the reactor inlet by 15%, the conversion of n-butane and the yield of maleic anhydride increased by 6.89% and 3.13%, respectively, while the amount of acrylic acid formed was reduced by 2.10%. Conversely, increasing the molar flow of oxygen at the reactor inlet by 15% led to a 13.12% increase in the molar percentage of acrylic acid, whereas decreasing the oxygen flow by 15% reduced the molar percentage of acrylic acid by 10.77%. Increasing the pressure of the reaction mixture at the reactor inlet by 15% raised the molar percentage of acrylic acid by 6.93%, while decreasing the pressure by 15% reduced it by 8.04%. The selectivity of acrylic acid increases with higher inlet pressure due to enhanced n-butane conversion. Given that the main objective of the n-butane oxidation process to maleic anhydride is to achieve high n-butane conversion and maleic anhydride yield while minimizing acrylic acid formation, the optimal strategy is to reduce the molar flow of n-butane at the reactor inlet.