Effect of the flow pattern on catalytic reaction of propylene hydrogenation through structured catalyst bed: Mathematical modeling and experiment observations

This novel study is experimental and modeling. In experimental section a pilot package including trickle bed reactor, automatic dosing pump, measuring instruments, gas chromatograph apparatus and five sample points along the reactor were employed to investigate the performance of propylene hydrogenation through structured catalyst bed under concurrent and countercurrent flow patterns. The experimental setup was configured in two different modes providing countercurrent and concurrent pattern for liquid phase and gas phase flow. First liquid propane containing propylene impurity flew from top of the reactor and hydrogen was injected from bottom as a gas phase counter-currently thereafter liquid and gas contacting phases both flew from bottom side of the reactor concurrently. Propylene content of liquid propane was hydrogenated through structured catalyst bed filling the pilot reactor and sampling has been done after establishing steady state conditions. In modeling a set of 12 partial differential equations (PDEs) were developed for dynamic modeling of current process including mass transfer and momentum transfer equations in liquid and gas phase. Afterward orthogonal collocation method was utilized to solve developed PDEs. Finally the results of mathematical modeling showed good consistency with experimental data. Furthermore, the sample analysis showed nil concentration of propylene in countercurrent flow in several operating condition, however nil concentration of propylene was not reported in concurrent flow pattern even by increasing the liquid flowrate.