(599d) The Process of Dehydrogenating N-Paraffins Into Mono-Olefins: Simulation and Optimization

Nowadays, detergents form one of the most developing markets in the world; note that linear alkylbenzene is the main component of these agents.
The major stage of linear alkylbenzenes (LABs) production is dehydrogenating the 10–13 n- paraffins into mono-olefins, performed by means of Pacol-Define assembly.
Conversion of paraffins into olefins in Pacol reactor makes 8–10%, in order to ensure high level of selectivity in mono-olefins production. Due to relatively low rate of n-paraffins generation in Pacol reactor, significant recycle of the paraffins from alkylation block to Pacol block is provided.
The aim of work is to investigate feasibility of improving the performance of the existing production process by simulation and optimization.
To develop the reactor’s model, kinetic data on the process evolution from certain sources have been analyzed.
The estimation results have motivated the authors to suggest redesigning the reactor, i.e., implementing the process in two serially connected reactors (instead of the only one) with the catalyst volumes satisfying the ratio of 1:0.15.
Two-reactor scheme of dehydrogenating the n-paraffins has been simulated in UniSim; it has been studied in the context of the following problems.
(1) increasing the level of conversion in the target reaction;
(2) increasing the rate of specific LAB production subject to 1-kg catalyst (under the same level of conversion).
In work model of complex industrial process of dehydrogenating the n-paraffins was improved and verified; principal feasibility of 15%-increase in conversion of 10–13 fractions in Pacol reactor has been demonstrated under the modified temperature mode in the reactor scheme(i.e., involving low-temperature and high-temperature reactors instead of the single reactor). Simulation model within the proposed scheme of reactor operation has been developed. It allows for solving the problems of structural and parametric synthesis of optimal chemical-engineering system for the dehydrogenating process. Simulation algorithm and relevant recommendations regarding the redesign of the reactor scheme used in Pacol-Define assembly have been provided.