Automation of a fixed-bed continuous–flow reactor

This paper describes the design and operation of a laboratory plant with a fixed-bed continuous-flow reactor, fully automated and controlled from a personal computer. The automated variables include two gas flows, one liquid flow, six temperatures, two pressures, one circulation of a cooling liquid, and 10 electrovalves. An adaptive-predictive control system was used. The chemical process chosen to run the automated reactor was the conversion of methanol to gasoline over a ZSM-5 catalyst. This is a highly exothermal process, so a cascade control system had to be used to control the reactor internal temperature. Pressure and weight hourly space velocity (WHSV) were fixed at 1 arm and 1.5h(-1) respectively. Accurate control (±0.2(°)C) of the reactor’s internal temperature was achieved and repeatability for the conversion of methanol to gasoline was good.