Overall control strategy of a coupled reactor/columns process for the production of ethyl acrylate

Ethyl acrylate (EA) is widely used in industry as a precursor for varnishes, adhesive, and finishes of papers and textiles. This important ester can be produced directly from ethanol (EtOH) and acrylic acid (AA) via esterification reaction with the presence of sulphuric acid as homogeneous catalyst. The proposed design flowsheet of this process includes a CSTR reactor coupled with a rectifier and an overhead decanter. In order to further purify the final EA product, another stripper is needed with its top vapor recycled back to decanter. The simplest and industrial easily applicable overall control strategy will be investigated with only one tray temperature control loop in each of the two columns. The final proposed overall control strategy of this process is found to be different than another similar coupled reactor/columns process published earlier [I-L. Chien, Y.P. Teng, H.P. Huang, Y.T. Tang, Design and control of an ethyl acetate process: coupled reactor/column configuration, J. Proc. Cont. 15 (2005) 435–449]. Both EtOH and AA feed flow rates are used as manipulated variables in the overall control strategy with CSTR heat duty left as throughput manipulator for the overall process. The final EA product with stringent specifications of 0.1 wt% EtOH and 0.005 wt% AA impurities can be achieved with this proposed overall control strategy despite feed flow rate and feed composition disturbances.