Process for n-butyl acrylate production using reactive distillation: Design, control and economic evaluation

Abstract

n-Butyl acrylate is produced at industrial scale from acrylic acid and n-butanol using strong acidic homogeneous catalysts. The associated well-known problems (corrosion, product purification, and disposal of spent catalyst) lead to high operating costs and a continuously increasing difficulty to comply with environmental regulations. Employing solid catalysts and process intensification technologies can overcome these drawbacks. However, the literature is scarce in studies describing the development of complete plants.Here, the design, control and economic evaluation of a reactive distillation-based process are presented. Since n-butanol is not completely converted in one pass, a decanter–flash system is used to recover and recycle the alcohol, and obtain a high purity waste water stream. To control the purity of the acrylate product when throughput changes or fresh reactants get contaminated, direct control using concentration measurement is required. Indirect control using temperature measurement alone is insufficient; since constant tray temperature cannot hold constant the concentration profile in the column, the acrylate purity always shows an offset. The process robustness is proved by rigorous simulations in Aspen Plus Dynamics. The economic analysis shows key economic indicators similar with those of other solid-based catalytic processes presented in literature.