A comprehensive sensitivity analysis on the performance of pseudo‐steady propane thermal cracking process

Abstract

The propane thermal cracking reactor process is investigated in an industrial furnace with an alternative wall burner arrangement. Temperature and heat distribution of the furnace is obtained by three‐dimensional computational fluid dynamics (CFD) simulation technique using Ansys Fluent software. Ten calculation domains are adopted to decrease calculation costs. Different fuel rate ratios are selected as the main effective parameter on reactor performance. Different ratios of base fuel rate (0.0695 kg/s) have been considered. The obtained reactor tube wall temperature profile is used for a one‐dimensional pseudo‐steady reactor operation. By the proposed new arrangement, the created coke layer thickness is lower about 3 mm compared with the base case after 700 h. Meanwhile, Propane conversion is increased by 4%. Besides, reactor feed flow rate variations are considered one of the essential parameter on reactor operation. Despite surging in propylene yield after coke formation, ethylene yield decreases during the process. By increasing the fuel rate in each reactor flow rate, ethylene increased while propylene yield descended. The maximum allowable pressure drop is 2.7 bar. At 0.5ṁ fuel rate and 0.85 kg/s reactor flow rate, pressure drop, reactor lifetime, and ethylene yield are 1.23 bar, 1444 h, and 28%; respectively. In the reactor flow of 0.85 kg/s, by raising fuel rate 0.5–2ṁ ethylene yield is increased from 28% to 46.83%, while process operating time is reduced to 780 h. According to the results, 0.8–0.85 kg/s could be considered as an appropriate range for reactor feed flow rate.