Modeling and optimization of acetylene hydrogenation reactors using commercial process simulator

Abstract

In chemical engineering plant operation, problems of inefficient usage of materials and energy arise over time. For effective solutions, many measures could be selected to overcome them. Process simulation and optimization, a selecting procedure for obtaining the best efficient solution, is widely used by process engineers. This research addresses the addresses the problems of finding the optimal operating condition for a front-end acetylene hydrogenation reactors, a combination of a lead, intermediate and guard reactors. Modeling of the reactors based on base case design was achieved by using three plug flow reactors connected in series using a lumped parameter as a function of catalyst deactivation and pre-exponent factor in Arrhenius with Peng-Robinson thermodynamic properties. Data fit and reconciliation was modify the lumped parameters to fit the model with actual plant data. Weight analysis was made to in crease the precision of acetylene concentration to be leverage with other components. A number of 10 equal-size CSTRs connected in series having the same volume as a single plug flow reactor was also developed. Results show similar predictions for both reactor models on the period of study. Updating the lumped parameter of both the plug flow and CSTR model was recommended in order to obtain an accurate prediction over a longer period of time. The catalyst deactivation rate alone was carried out to investigate the catalyst deactivation over a longer period of time. The catalyst deactivation rate alone was carried out to investigate the catalyst deactivation profile apart from the lumped parameter in the kinetic reaction model. The result shows a significant deactivation profile along the study period of 6 months. An optimization study of the optimal condition of which were to maximize the ethylene gain or minimize ethane gain was made. The results were obtained achieving pu to 43.6 kg/hr of ethylene gain done by increasing the lead reactor form 68.6℃ to 69.3℃, decreasing the intermediate reactor form 71.2℃ to 67.2℃ and decreasing the guard temperature from 54.5℃ to 37.2℃. Sensitivity analysis of the temperature and acetylene concentration changes shows that the lead reactor could remove up to 95% of acetylene, the rest of acetylene is then removed at the intermediate reactor.