Process simulation and optimization of dodecyl benzene sulfonic acid production plant

Abstract

The aim of work is to design sulfonating plant on the basis of a hydrophilic sulfonate head-group and a hydrophobic alkyl benzene tail-group reaction mechanism, study of kinetics and thermodynamics followed by a steady-state simulation for the process was done by ASPEN HYSYS (V8.8) through using Peng-Robinson fluid package. Then heat integration of the process, done by using Aspen Energy Analyzer and studies of the influence parameters on the simulated process of dodecyl benzene sulfonic acid. Alkyl benzene sulphonate is produced due to the sulphonation reaction of an alkylbenzene (LAB) plus a sulphonating agent in a falling film sulphonator to produce sulfonic acid (LABSA).The modeling of dodecyl benzene sulfonic acid plant depends on : Air drying, Sulphur melting and proportioning, Sulphur combustion and SO3 production, Film sulfonation. Dodecyl benzene sulfonic acid production rate is influenced by changing of the following factors: the sulfur molar flow rate, molar flow rate of air and pressure of dodecyl benzene, the results of optimization shows that : The optimum operating Molar flow rate of sulfur is lies in the range of [3:3.5] Kg.mol/h, The optimum operating Molar flow rate of Air is 25 Kg.mol/h, The optimum operating Molar flow rate of Dodecyl Benzene is 3.1 Kg.mol/h and The optimum operating Pressure of Dodecyl Benzene is 70 KPa. For heat integration, a proposed heat exchanger network is generated which made the process functional without external heating. Generation of the top 10 heat exchanger network (HEN) leads to: the best case scenario from the top 10 scenarios from the point of cost and also from the point of cooling and heating required was design (9). After heat integration, the total amount of cooling demand decreased from 912620.50 KJ/h to 890261.56 KJ/h and the total amount of heating demand decreased from 22358.94 KJ/h to 0KJ/h.