Kinetic Model of Olefins/Isobutane Alkylation Using Sulfuric Acid as Catalyst

Abstract

The alkylation of isobutane and low molecular olefins using strong acid as catalysts is an important process in the petrochemical field, and its product, alkylate, is an ideal gasoline blending component due to high octane number, low vapor pressure, low sulfur, and lack of aromatics. To better meet the optimization process of the simulation of the alkylation unit, a reaction kinetic model with 20 reactions based on industrial data was developed, in which the alkylation products were divided into lumped components in detail. The reactor model was established based on the flow state and structural pattern of the industrial reactor, considering the internal circulation flow, and is suitable for the simulation of the DuPont alkylation process. Also, eventually, the model parameters were solved by the nonlinear least-squares fitting method. The results of the validation calculations showed that the kinetic model fitted the experimental data with good agreement. In addition, the reaction kinetic model was used to predict the influence of operating conditions, which is consistent with the trend in actual industrial production.

Production of Alkylate Gasoline Using Methanesulfonic Acid as a Green Catalyst in the Presence of Real Refinery Hydrocarbon Mixtures

“…The mixing of isobutane with the acid phase is essentially the controlling step of the reaction, and this can be triggered by temperature, time and the acid/HC ratio. 31 Therefore, in this section, all of these parameters are studied with MSA in the liquid form, analogously to the H 2 SO 4 -based process. as shown in Figure 1, reveal that low temperatures do not favor high butene conversion; however, when the temperature is raised, the butenes are converted to a higher extent.…”

“…Isobutane/butene alkylation reactions are very complex in nature, and they are controlled by mass transfer and diffusion of reactants through the active site of the catalyst. The mixing of isobutane with the acid phase is essentially the controlling step of the reaction, and this can be triggered by temperature, time and the acid/HC ratio . Therefore, in this section, all of these parameters are studied with MSA in the liquid form, analogously to the H 2 SO 4 -based process.…”

“…Reaction time is one other important parameter to take into consideration when acid catalysts are applied to the isobutane alkylation reaction. It is well-known that the isobutane/butene alkylation reaction is a kinetic-controlled process, which means that the yield of TMPs and side products is determined by the kinetics of the reaction and not by the thermodynamics; , then, a screening of the catalyst applying different reaction periods is critical to envisage its effect on the selectivity to C8s and TMPs. Figure A shows such a relationship at 5, 10, 15, and 30 min.…”

A Review of Computational Fluid Dynamics Modeling for Isobutane Alkylation: Process Optimization, Reactor Design, and Future Perspectives

“…Efficient operation of the alkylation process necessitates optimal conditions, emphasizing both effective mixing of hydrocarbon and catalyst as well as rapid separation of product and catalyst. In particular, the production of dimethylhexane (DMH) carbonium ions primarily stems from factors such as residence time and agitation conditions rather than predominantly relying on TMP carbonium ions isomerization, as the quantity of DMHs undergoes substantial changes under varied operational conditions …”

“…In particular, the production of dimethylhexane (DMH) carbonium ions primarily stems from factors such as residence time and agitation conditions rather than predominantly relying on TMP carbonium ions isomerization, as the quantity of DMHs undergoes substantial changes under varied operational conditions. 46 The form of the catalyst in the solid catalyst alkylation of isobutane holds substantial influence over pivotal industrial parameters, including bulk flow, voidage, drop in pressure, thermal transfer, reaction kinetics, and the coefficient of effectiveness governing internal diffusion. Efficiently designing catalyst dimensions and shapes within a fixed-bed reactor holds significance in minimizing the impact of diffusion on reactions through shortening the distance over which diffusion takes place.…”