(598d) Simulation Based Design of Simulated Moving Bed Reactor for the Production of Ethyl Chloro Acetate

Simulated moving bed reactor (SMBR) is a single-unit operation apparatus with four sections, each with a set number of beds. In this process, the reaction and separation happen simultaneously with the adsorption and desorption. This makes achieving complete conversion of the limiting reactant in equilibrium-constrained reactions feasible. Its design is difficult because of the thirteen degrees of freedom, which include feed and desorbent concentrations and associated flow rates, raffinate and extract flow rates, four sections flow rates, switch time, and column dimensions. Desorption recovery from the extract and raffinate phases completes the SMBR process and primarily controls operational costs. Conversely, the capital cost is contingent upon production . Thus, the goal of this study is to use a streamlined strategy to obtain optimum output with the least amount of solvent required. Rather than combining computationally exhaustive simulation with mathematical optimization. We used a simplified approach and the reaction of interest undertaken is ethyl chloro acetate (ECA) synthesis by reacting mono-chloro acetic acid with ethanol, catalyst/adsorbent Amberlyst-15.
The solution methodology adopted is the triangle theory, a well-developed approach for simulated moving beds (SMBs) without reaction . The process employs the linear adsorption isotherm and maintains consistency on internal flow rate ratios (m1, m2, m3 and m4) to guarantee the full conversion of the limiting reaction, the purity of the extract, and the raffinate. This hypothesis is expanded to include SMB with reaction, or SMBR. Equation for the SMBR model was solved in MATLAB with appropriate boundary conditions.
The parameters m1 and m4 were chosen carefully but m2 and m3 had a range of values as per constraints. Therefore, the feasibility of m2 -m3 pairs were studied and they were plotted on triangle diagram, as shown in Figure 1. Further, the effect of various parameters was studied such as effect of residence time , flow rates of all four sections, pseudo solid velocity etc. The parameters were optimized for m2-m3 feasible pairs through different paths that gave minimum desorbent and maximum productivity.