Substitute natural gas

About: Substitute natural gas is a research topic. Over the lifetime, 1216 publications have been published within this topic receiving 23604 citations. The topic is also known as: synthetic natural gas.

Effect of sulfidation temperature on the catalytic behavior of unsupported MoS2 catalysts for synthetic natural gas production from syngas

Abstract: Unsupported MoS2 catalysts were obtained by thermal decomposition of ammonium tetrathiomolybdate (ATM) or ammonium heptamolybdate (AHM) using sulfur powder as sulfiding agent at variable sulfidation temperature (400–550 °C). The CO conversion, selectivity and yield of CH4 on the catalysts were studied for the methanation reaction. It was found that CO conversion increased with temperature rise at first, reached maximum value at sulfidation temperature of 450 °C and then decreased sharply with further increase of temperature. The catalyst derived from ATM could get higher CO conversion than the catalyst from AHM because of the structural similarity between ATM and MoS2. XRD analysis demonstrated that amorphous MoS2 was favorable for the methanation reaction and a crystal transition of MoS2 nanoparticle happened during the methanation reaction. The higher the sulfidation temperature was, the more easily regular crystal structure of MoS2 formed. TEM characterization results showed that at the optimum sulfidation temperature of 450 °C, the length and stacking degree of MoS2 crystallite were the highest and so more active sites could reside on the edges of MoS2 slabs for CO methanation. The crystal growth of MoS2 particle and its structure change are probably the reasons for the deactivation of the MoS2 catalysts with the increase of sulfidation temperature. In addition, it is the loss of surface sulfur that caused deactivation of the catalyst with reaction time.

Integration between biomass gasification and high-temperature electrolysis for synthetic methane production

Abstract: The energy system analysis of an integrated process producing synthetic natural gas (SNG) from woody biomass has been carried out. Two different process configurations have been proposed and modeled, considering the integration between biomass gasification, solid oxide electrolysis (SOEC) and catalytic reactors for methane synthesis. The two investigated process configurations differ in the size of the SOEC unit. In the first configuration, the electrolysis unit is sized to increase H2 content in the produced syngas to satisfy the methanation reaction stoichiometric requirement. In the second configuration, electrolysis provides to the gasifier the requested amount of oxygen. For this second configuration, an additional section composed of a water gas shift (WGS) reactor and a carbon capture and sequestration (CCS) unit is required to adjust the reacting gas composition and thus to ensure the proper stoichiometry for the methanation process. The two different configurations have been compared at the same gasification condition. The gasifier has been modeled and studied to choose the gasification parameters' appropriate values, as equivalence ratio and steam-to-biomass ratio, and their impact on gasification outlet temperature and syngas composition. The whole process has been analyzed from a thermodynamic standpoint. After a thermal integration between the streams of the plant, energy efficiency has been calculated for both configurations: the first one (SOEC sized on hydrogen requirement) presented an efficiency of 71.7 %, while the second one (SOEC sized on oxygen requirement) showed an efficiency of 66.8 %.

Ferrite catalysts derived from electroplating sludge for high-calorie synthetic natural gas production

Abstract: In this study, a ferrite catalyst has been prepared through a facile hydrothermal method using industrial Zn and Fe-rich electroplating sludge as raw materials and utilized for the first time as an efficient catalyst for methanation of syngas. The ferrite catalyst showed pretty good catalytic performance during the stability test at 340 °C for 300 h, meanwhile exhibited a higher resistance to thermal shock (600 °C for 12 h) than that of the catalyst prepared from pure chemical reagents or commercial methanation catalyst. More importantly, a high-calorie natural gas with heating value of 41.73 MJ Nm −3 could be obtained via methanation of syngas over the ferrite catalyst derived from electroplating sludge. Thus, this work provides some new insights for utlising solid waste as raw material for methanation catalyst, which is very cheap.