Methane Dry Reforming at High Temperature and Elevated Pressure: Impact of Gas-Phase Reactions

Abstract

Catalytic dry reforming over a platinum-based catalyst is described experimentally and numerically in a laboratory pilot-plant flow reactor. The results reveal that coking in the upper part of the catalyst bed and at the entrance of the reactor occurs, depending on the composition of the reaction mixture and the respective temperature. To a significant extent, gas-phase reactions play a role as being the cause for the observed coking behavior in the reforming of methane in the presence of carbon dioxide at high temperatures of 1123−1273 K and at 20 bar. Hydrogen addition can inhibit coke formation better than water addition. The reactor is modeled by a one-dimensional description of the reacting field using elementary-step reaction mechanisms of up to 4238 gas-phase reactions among 1034 species and 58 heterogeneous reactions among 8 gas-phase species and 14 surface-adsorbed species. The study leads an optimized positioning of the catalyst in a technical reformer tube.

Surface Reaction Kinetics of Steam- and CO2-Reforming as Well as Oxidation of Methane over Nickel-Based Catalysts

“…The formation of coke can lead to lower catalytic activity and even complete catalyst deactivation, depending on the amount of solid carbon deposited on the surface [22][23][24][25][26]. Hydrogen and water have recently been studied as inhibitors of coke formation in dry reforming of methane at higher pressure and temperatures [26]. The influence of hydrogen and water in DR of methane was studied in the fixed bed reactor at atmospheric pressure, 4 slpm flow rate, residence time of 0.013 s, temperatures between 373 and 1173 K and inlet mixture of 1.6% CH4, 2.1% CO2 and 1.8% H2 in N2 dilution.…”

“…Coke deposition on catalysts and reactor pipe walls are serious problems in many industrial reactors that involve methane as fuel; in some cases it leads to the blocking of reactor tubes as well as the physical disintegration of the catalyst structure [22][23][24][25][26][27].…”

Pyrolysis-catalytic dry (CO 2 ) reforming of waste plastics for syngas production: Influence of process parameters

“…A study on dry reforming of methane over a Ni/ -Al2O3 catalyst in a fixed bed continuous flow quartz reactor and direct current corona discharge found an increase selectivity for CO and decreased carbon formation on the catalyst surface [13]. Dry methane reforming is not only affected by temperature, but also the CH4/CO2 ratio, mass to flow ratio, catalyst selection and reaction mixture [14][15][16].…”

On the coke deposition in dry reforming of methane at elevated pressures

“…To study the pathway of coke deposition, 13 CO 2 was used to trace the origin of carbon formation. Using a previously established network of elementary surface reactions [30,31], reaction pathways on Pt-and Ni-based catalysts were theoretically analyzed. The nature and concentration of carbon deposited were investigated by temperature-programmed oxidation and electron microscopy.…”