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.

Hydrogen production method

Abstract: A method of producing a hydrogen product stream in which a steam stream is reacted with a hydrocarbon containing stream within a steam methane reformer. The resulting product stream is subjected to a water gas shift reaction and then to pressure swing adsorption to produce the hydrogen product stream. The hydrocarbon stream is alternatively formed from a first type of feed stream made up of natural gas, refinery off-gas, naphtha or synthetic natural gas or combinations thereof and a second type that is additionally made up of a hydrogen and carbon monoxide containing gas. During use of both of the types of feed streams, the flow rate of the steam stream is not substantially changed and reformer exit temperatures of both the reactant and the flue gas side are held essentially constant.

Synthetic natural gas via integrated high-temperature electrolysis and methanation: Part I—Energy performance

Abstract: In this two-part paper the production of synthetic natural gas (SNG) through integrated plants featuring high temperature electrolysis and subsequent syngas methanation is analyzed. Part one focuses on plant configuration and performance evaluation. Part two focuses on cost for an economic assessment. Two different ways to produce SNG have been analyzed: the first option features a plant that integrates steam electrolysis with methanation (Sabatier reaction); the second one considers co-electrolysis of water and carbon dioxide coupled with TREMP™ (Topsoe recycle energy-efficient methanation process). In both cases high temperature electrolysis with solid oxide cells (SOEC) technology has been employed. A power input of 10 MWe was taken as the DC electricity input for both plant SOEC generators, based on power-to-gas plants now under construction in Europe. Sensitivity analyses were used to evaluate the impact of selected operating parameters on the plant performance. Especially the pressurization of the SOEC brings a reduction of the over all electrical input required to run the plant. By operating a pressurized SOEC, post-electrolysis syngas compression (that would be required otherwise because methanation takes place at ≈33 bar) is partly replaced by liquid water pumping before electrolysis. Thermal integration based on the pinch analysis methodology was also applied in order to calculate the minimum external (thermal) energy requirement. Notably, most of the heat required for vaporizing and super-heating the electrolysis water can be recovered from the exothermic methanation section. Hence, a good thermal integration is available between SOEC and syngas upgrade catalytic section. This boosts the electricity-to-SNG efficiency to values as high as 80%. The co-electrolysis plant shows a LHV efficiency of 81.4% that is more than five percentage points higher than the steam electrolysis case (76%): notably exothermic in-stack methanation – that occurs in the case of high pressure co-electrolysis assessment – allows for a reduction of the electricity input to the SOEC for the same amount of syngas produced among the two plants.

Chemical Methanation of CO2: A Review

Abstract: The chemical methanation of CO2 may become a ubiquitous process for the production of renewable substitute natural gas from any CO2 source coupled with renewable hydrogen. The produced gas can be fed into the natural gas pipeline or used as fuel. Over the past few years, great efforts have been made in developing the process of CO2 methanation. In this paper, the chemical methanation, which is the most common process, is reviewed. The purpose is to present a comprehensive updated review of the process. The CO2 methanation, covering the process mechanisms, thermodynamics, catalysts, kinetics, and reactors are discussed with the aim to outline the pathways for the future development of the methanation process.