Enhancement in Research Octane Number and Hydrogen Production via Dynamic Optimization of a Novel Spherical Axial-Flow Membrane Naphtha Reformer

Abstract

Spherical axial-flow membrane reactors (SMR) can be proposed as a promising alternative for conventional tubular reactors (CTR) in the catalytic naphtha reforming process. In this study, the operating conditions and design parameters of SMR are optimized via a differential evolution (DE) method to maximize the hydrogen yield, the reformate production rate, and the aromatic content of reformate (octane number). Regarding this, 26 decision variables such as the membrane thickness, catalyst mass distribution, and flow distribution of sweeping gas are optimized, and the performance of the SMR is evaluated under optimized operating conditions. The optimization results show that the operating costs can decrease sharply with a decrease in the sweeping gas streamlines’ pressures where they decline from 985, 1810, and 2000 kPa in the first, the second, and the third reactors of nonoptimized SMR to 242.4, 563.1, and 796.6 kPa in optimized SMR, respectively. Moreover, the research octane number (RON) of gasoline can improve well in optimized SMR owing to the achievement of higher aromatic yield and the aromatic content of the reformate. Consequently, an optimized SMR configuration can properly address the increasing demand for high-octane gasoline. The superiority of the optimized SMR configuration to CTR can be counted as assisting the membrane concept, lower pressure drop along the reaction side, and utilizing the optimum operating conditions.