Development and application of composite ionic liquid catalyzed isobutane alkylation technology

Abstract

Alkylate from isobutane alkylation is an ideal blending component of motor gasoline. In China its blending ratio in gasoline is continuously increased with upgrading the gasoline quality standards. A series of studies on ionic liquid catalyzed isobutane alkylation were carried out around a new industrial process of alkylate production. The composition, structure and catalytic performance of chloroaluminate ionic liquids were studied, and a composite ionic liquid (CIL) with high catalytic activity and high selectivity was designed and synthesized. The deactivation mechanism of CIL during isobutane alkylation was studied and a feasible regeneration scheme was developed, including a Lewis acid activity monitoring method of chloroaluminate ionic liquids. A long period (2 months) operation test was carried out in a pilot plant, and then the initial process development of CIL catalyzed isobutane alkylation technology (CILA) was completed. A new type static mixing reactor and a hydrocyclone were developed. The first industrial plant of CILA was designed and constructed. The plant includes feed pretreatment, alkylation reaction, catalyst regeneration, product separation and clean-up systems. The industrial operation results were excellent. Butene conversion reached 100%, research octane number of alkylate maintained stably at above 95 and could reached up to above 98 at optimal operating conditions, end boiling point of alkylate was below 198 °C, and Cl content in alkylate was below 5 mg/L. CILA can produce clean alkylate with clean process, having a good application prospect and promotion value.