Coke profile and effect on methane/ethylene conversion process

Abstract

The objective of this study was to investigate the coke profile with respect to time on stream and the change of product distribution due to catalyst deactivation. A fixed bed reactor was used to conduct this investigation. A series of runs were conducted using the Engelhard catalyst with fixed operating conditions. The only variable was the time on stream of each run. Six experiments were conducted starting with one hour time on stream up to six hours with an increment of one hour. In each experiment data on product flow rate, reactor temperature, and product distribution were collected. And at the end of each run, the amount of coke deposited on the catalyst was measured. Hydrogen concentration in the product distribution decreased as a function of time on stream. On the other hand, low and high end hydrocarbons increased with time on stream. The coke deposition kinetics for the catalyst at the process operating conditions can be estimated using Voorhies' empirical formula. The coke profile inside the reactor showed that the coke reaction follows a parallel mechanism to the main reaction. Ethylene was found to be the main coke precursor; however, the participation of methane in the coke reaction could not be neglected.