Assessing Industrial-Scale H₂SO₄-Catalyzed C4 Alkylation Enhanced by [N_1,1,1,1][C₁₀SO₄] Additives Based on a Complex Kinetic Model

Abstract

It is of vital importance to assess the effects of novel additives on the industrial-scale alkylation process before actual industrial operations. Herein, to evaluate the promotion of the novel [N 1,1,1,1 ][C 10 SO 4 ] additive on the industrial-scale H 2 SO 4catalyzed isobutane alkylation, a custom user model of the Aspen Plus simulation platform with embedded complex kinetic parameters was established to simulate the whole process. The prediction of the complex kinetic model can agree well with the continuous experimental alkylate distribution, including trimethylpentanes (TMPs), dimethylhexanes (DMHs), light ends (LEs), and heavy ends (HEs). There is a close agreement between the calculated results from the user module and the complex kinetic model with an error margin within 1%, thereby confirming the accuracy of the custom module and the kinetic model. For the process simulation, the introduction of 0.3 wt % [N 1,1,1,1 ][C 10 SO 4 ] additive can remarkably improve the selectivity of targeted TMPs and the yield of alkylate, even at the space time down to 20 min from typical 30 min in the pure used H 2 SO 4 system and at lower isoparaffin/olefin from 8:1 to 6:1, which is beneficial for the enhanced production capacity of alkylate. Specifically, the research octane number (RON) of alkylate can be maintained above 96.00, even with 40.72% decrease in space time as well as 33.3% decrease in the I/O ratio. Under optimized conditions, the production capacity of alkylate with [N 1,1,1,1 ][C 10 SO 4 ] additives can be increased by about 30% up to 134.01 kt/a from typical 103.13 kt/a in the pure used H 2 SO 4 system. This work provides a good guideline for the industrial application of novel additives for C4 alkylation.