Recent Developments in the Partial Oxidation of Methane to Syngas

Abstract

Natural gas is catalytically converted into several bulk chemicals such as ammonia, methanol, dimethyl ether, and synthetic liquid fuels by Fischer-Tropsch synthesis and similar processes. The main step in the conversion of natural gas to these products is the production of synthesis gas with the desired composition ranging from H 2 /CO = 3:1 used for the production of ammonia to the 1:1 mixture preferred for production of dimethyl ether. Catalysts and catalytic processes are important in the production of synthesis gas from natural gas. In this work, relevant catalytic systems employed recently in the production of syngas by the catalytic partial oxidation of methane, as well as experimental evidences on the reaction mechanisms are examined. Differences in methane dissociation, binding site preferences, stability of OH surface species, surface residence times of active species and contributions from lattice oxygen atoms and support species are considered. The methane dissociation requires reduced metal sites, but at elevated temperatures oxides of active species may be reduced by direct interaction with methane or from the reaction with H 2 and CO (or C). The comparison of elementary reaction steps on Pt and Rh illustrates the fact that a key factor to produce hydrogen as primary product is a high activation energy barrier to the formation of OH. Another essential property for the formation of H 2 and CO as primary products is a low surface coverage of intermediates, such that the probability of O-H, OH-H and CO-O interactions is reduced.

Catalytic Hydrogen Production from Methane Partial Oxidation: Mechanism and Kinetic Study

“…Several noble catalysts have been used in CPOM reactions, especially group VIII–X (8–10) metals, e.g., rhodium (Rh), ruthenium (Ru), palladium (Pd), lanthanum (La), and platinum (Pt) , , , , where rhodium demonstrated good activity , . It was reported that Rh is more selective to syngas production (CO and H 2 ) than Pt in CPOM reactions in the corresponding catalysts of Rh/ α ‐Al 2 O 3 and Pt/ α ‐Al 2 O 3 , respectively .…”

Perovskite catalysts for methane combustion: applications, design, effects for reactivity and partial oxidation

“…In homogeneous processes, extreme temperatures, long residence time, and excessive coke formation decrease the controllability of the reaction. 236 Pt, Rh, Ir, and Pd are frequently used in the POM as precious (noble) metals. Ni and Co catalysts are also frequently in use as nonnoble metals.…”

Combined synthesis and hydroprocessing on a cobalt catalyst on a cobalt-containing zeolite catalyst

“…TEM micrographs of reduced composite catalyst and histograms of cobalt particle size distribution Активность катализатора определяли на синтез-газе (% об. : СО -20; Н2 -40; N2 -40), моделирующем состав газа, получаемый при использовании на первой стадии технологии XTL в качестве окислителя воздуха вместо кислорода [21,22]. Использование дешевого и доступного окислителя позволит сократить капитальные и эксплуатационные затраты при создании производства XTL, а присутствие в синтез-газе азота уменьшить вероятность перегрева катализатора ФТ.…”