Showing papers on "Substitute natural gas published in 2021"
TL;DR: In this paper, the up-to-date developments on CO2 methanation catalysts and the optimal synergistic relationship between active metals, support, and promoters during the catalytic activity are reviewed.
79 citations
TL;DR: In this article, the authors investigated the recycling of carbon dioxide from gas-fired power plant emissions into synthetic natural gas based on a novel power-to-gas process with the aim of chemical energy storage and emission reduction.
45 citations
TL;DR: In this paper, the results of experimental research from gasification test runs of different biogenic fuels, carried out with an advanced 100kW pilot plant over the last 5 years at TU Wien, are presented.
Abstract: In many processes proposed for biorefineries, recycling procedures, and industrial or agricultural production processes, residue is generated which could be further transformed by thermochemical conversion via gasification. The technology of dual fluidized bed steam gasification is capable of producing a valuable product gas out of such residue. The generated nitrogen-free product gas can be used for heat and power production and is suitable for separating gases (e.g. hydrogen). However, if the product gas is cleaned, its use as syngas is more beneficial for manufacturing renewable chemical substances, like synthetic natural gas, methanol, Fischer–Tropsch liquids, or mixed alcohols. This paper presents the results of experimental research from gasification test runs of different biogenic fuels, carried out with an advanced 100 kW pilot plant over the last 5 years at TU Wien. The focus is to provide an overview of measured results validated by mass and energy balances and to present key calculated performance indicating key figures of the test runs. In this way, the influence of various operational parameters and the composition of the product gas are evaluated. The presented results form the basis for the proper design of suitable gas-cleaning equipment. Subsequently, the clean syngas is available for several synthesis applications in future biorefineries.
40 citations
TL;DR: In this paper, the authors proposed a sustainable way to control plastic-derived pollution and alleviate the energy crisis by using supercapacitor electrodes, such as KOH-activated carbon (AC-K) with a hierarchical porous structure, a high specific surface area and abundant surface functional groups.
39 citations
TL;DR: In this paper, an integrated CO2 capture and conversion process to Synthetic Natural Gas (SNG) is simulated, and different scenarios are defined considering the application to a cement plant flue gas and the production of renewable hydrogen.
Abstract: Carbon Capture Utilization and Storage (CCUS) technologies are receiving increasing interest and its implementation at world scale appears to be crucial to reduce CO2 emissions. In this context, Power-to-Gas technologies (PtG) are very promising, allowing to store renewable electricity and valorize captured CO2 to produce Synthetic Natural Gas (SNG), among other. The present work simulates an integrated CO2 capture and conversion process to SNG, and investigates its techno-economic and environmental performances. Different scenarios are defined considering the application to a cement plant flue gas and the production of renewable hydrogen. An advanced CO2 capture unit is implemented, considering a configuration (Rich Vapor Compression and Inter Cooling) and a solvent (MDEA + PZ) allowing to minimize its specific energy consumption (35 % regeneration energy savings in comparison with a conventional amine-based CO2 capture system). The excess heat released by the catalytic conversion is recovered for the solvent regeneration maximizing the amount of captured CO2. From the scenarios analyses, it is shown that integrating the CO2 capture and conversion steps is beneficial for reducing both the net CO2 emission to the atmosphere, by 45 %, and the contribution to fossil depletion, by 81 %, in comparison with the non-integrated one, as the production of fossil-based natural gas is replaced by renewable SNG. The proposed process leads to a cost of 2.39 € per kg Raw-SNG, with expected revenues of 0.87 € per kg Raw-SNG. Significant subsidies and incentives would thus be needed to compete with conventional energy prices for natural gas (0.55 € per kg).
36 citations
TL;DR: In this paper, a review identifies and quantitatively analyses 30 life cycle assessment studies on the greenhouse gas emissions of renewable gases, comparing their results and deriving the main determinants on their environmental friendliness.
Abstract: Natural gas is an energy carrier of predominant significance for today's electricity and heating sectors. However, science heavily discusses the actual environmental burden of natural gas mainly due to the uncertainty in upstream methane losses during its extraction and transportation. In this context, numerous technologies pave the way for the production of renewable methane to replace natural gas: biomethane from anaerobic digestion of biomass, substitute natural gas (bio-SNG) from gasification and Power-to-Gas via water electrolysis and subsequent methanation. In recent years, numerous studies aimed at analysing the life cycle carbon intensity of those renewable gases. Given the high degree of freedom in the methodology of life cycle assessment (LCA) however, the studies are highly dependent on the respective boundary conditions and assumptions. To summarise and discuss the different findings, this review identifies and quantitatively analyses 30 life cycle assessment studies on the greenhouse gas emissions of renewable gases, comparing their results and deriving the main determinants on their environmental friendliness. A comparison between the results for renewable gases and existing literature reviews on the LCA of fossil natural gas shows the considerable emission reduction potential of renewable gases. This however requires the consideration and right implementation of the main influencing factors (inter alia the storage of digestate in closed tanks for biomethane, heat extraction of excess heat for bio-SNG, or the use of renewable electricity for Power-to-Gas) and is not a mere result of the technologies per se.
28 citations
TL;DR: In this paper, a new process of coal chemical looping gasification that creates synthetic natural gas is proposed, where low energy consumption for CO2 capture is achieved simultaneously by increasing the CO2 concentration.
25 citations
TL;DR: In this article, the performance of 15.15%Ni-12.5%Co-5wt%Fe-Al2O3 catalyst in CO2 methanation reaction was assessed.
23 citations
TL;DR: In this article, the energy system analysis of an integrated process producing synthetic natural gas (SNG) from woody biomass has been carried out, considering the integration between biomass gasification, solid oxide electrolysis (SOEC) and catalytic reactors for methane synthesis.
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 %.
23 citations
TL;DR: In this paper, a Ni/CeO2 catalyst with novel structure was designed and synthesized through impregnation of Ce-based metal organic framework (MOF) with Ni precursor followed by calcination process.
22 citations
TL;DR: In this paper, four energy storage systems (Power-to-Gas-To-Power) were analyzed that allow electrolysis products to be fully utilized immediately after they are produced, where the electrolysis process was supplied with electricity from a wind farm during off peak demand periods.
TL;DR: In this paper, the feasibility of integrating syngas biomethanation with other processes, i.e., electrolysis and gasification, has not been thoroughly assessed so far by the existing literature.
Abstract: Biological methanation (biomethanation) of biomass-derived syngas can be a promising alternative to catalytic methanation, due to its milder operating conditions, and could improve the feasibility of power-to-gas and syngas upgrading systems. However, the feasibility of integrating syngas biomethanation with other processes, i.e., electrolysis and gasification, has not been thoroughly assessed so far by the existing literature. In this study, we carried out the techno-economic analysis of such integrated system and we compared it with the production of pure hydrogen. The results indicate that the two processes could produce 0.39 Nm3 of bio-derived substitute natural gas (bSNG) or 0.07 kg of bio-hydrogen (bH2) per kg of dry biomass, respectively. The process cold gas efficiency associated with the produced bSNG is estimated at 50.6%, with a 97.4% input hydrogen utilization efficiency. For bH2, the cold gas efficiency is 36.6%, with 85% hydrogen utilization. Gasification and gas compression were identified as the unit operations with the highest energy demand in both processes. The minimum selling prices (MSP) of the two products were estimated at 2.68 €/Nm3 for bSNG and 15.35 €/kg for bH2. While delivery costs and a limited production capacity pose additional challenges to the development of bH2 production on decentralized gasification plants, bSNG production for grid injection could become a more feasible alternative under appropriate incentive schemes. Key optimization opportunities for such process rely on better heat integration, lower pressure operation, and the use of waste biomass as feedstock.
TL;DR: In this paper, a highly active fibrous silica-beta zeolite (FS@SiO2-BEA) catalyst was prepared for CO2 methanation by a microemulsion process, and examined by N2 adsorption-desorption, field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), and electron spin resonance (ESR) spectroscopy techniques.
TL;DR: In this paper, a simulation-based optimisation model MIREG (Model for the Integration of Renewable Gases) is introduced to find transition paths to resolve the issue of the current market conditions.
Abstract: Natural gas plays an essential role in Germany's energy system, both in the heating and electricity sectors. In order to achieve climate goals, numerous technologies aim at substituting fossil with renewable gas. Those technologies start reaching technical maturity, yet they are mostly not economically competitive under the current market conditions. To find transition paths to resolve this issue this paper introduces the simulation-based optimisation model MIREG (Model for the Integration of Renewable Gases). Combining a system-dynamic simulation of the various renewable gas options with an optimisation model of the gas market, the model puts strong focus on the reproduction of gas market's mechanisms and the implications of a rising penetration of renewable gases. The model is then applied to analyse the effects of different developments of market conditions and funding strategies on the possible share of renewable gases in the German gas mix until 2050. Results show that if renewable gases are supposed to account for a significant share of gas consumed in Germany they either need to be funded substantially or market conditions have to change. For a share of 23% renewable gas in the gas mix CO2 prices for example would have to reach a level of 150 €/tCO2 by 2050 (300 €/tCO2 for 54%). The scenarios also indicate that in order to meet significant amounts of the German gas consumption with renewable gases, international solutions need to be aimed at e.g. by importing renewable gas from locations with high potential of renewable energy or by importing biomass.
TL;DR: In this paper, a power-to-gas system was designed and optimized, defining the number of involved catalytic cooled reactors, the number parallel tubes for each reactor and the staged CO2 injection to moderate the maximum temperature throughout the reactors.
TL;DR: In this paper, the authors presented an energy-efficient way for synthetic natural gas production using captured CO2 and renewable hydrogen, and evaluated five possible renewable hydrogen sources (photo fermentation, dark fermentation, biomass gasification, bio photolysis, and PV electrolysis) from an economic stand point using key performance indicators.
Abstract: Production of synthetic natural gas (SNG) offers an alternative way to valorize captured CO2 from energy intensive industrial processes or from a dedicated CO2 grid. This paper presents an energy-efficient way for synthetic natural gas production using captured CO2 and renewable hydrogen. Considering several renewable hydrogen production sources, a techno-economic analysis was performed to find a promising path toward its practical application. In the paper, the five possible renewable hydrogen sources (photo fermentation, dark fermentation, biomass gasification, bio photolysis, and PV electrolysis) were compared to the two reference cases (steam methane reforming and water electrolysis) from an economic stand point using key performance indicators. Possible hydrogen production capacities were also considered for the evaluation. From a technical point of view, the SNG process is an efficient process from both energy efficiency (about 57%) and CO2 conversion rate (99%). From the evaluated options, the photo-fermentation proved to be the most attractive with a levelized cost of synthetic natural gas of 18.62 €/GJ. Considering the production capacities, this option loses its advantageousness and biomass gasification becomes more attractive with a little higher levelized cost at 20.96 €/GJ. Both results present the option when no CO2 credit is considered. As presented, the CO2 credits significantly improve the key performance indicators, however, the SNG levelized cost is still higher than natural gas prices.
TL;DR: In this paper, a 20 kW fuel input bubbling fluidized bed facility with steam and oxygen as gasification agent was used to produce syngas with high H2 and CO concentrations of up to 0.37 m3 m−3 and 0.18 m3m−3, respectively.
Abstract: The conversion of biogenic residues to fuels and chemicals via gasification and synthesis processes is a promising pathway to replace fossil carbon. In this study, the focus is set on sewage sludge gasification for syngas production. Experiments were carried out in a 20 kW fuel input bubbling fluidized bed facility with steam and oxygen as gasification agent. In-situ produced sewage sludge ash was used as bed material. The sensitivity of the key operation parameters gasifier temperature, oxygen ratio, steam to carbon ratio, and the space velocity on the syngas composition (H2, CO, CO2, CH4, CxHy, H2S, COS, NH3, and tars) was determined. The results show that the produced syngas has high H2 and CO concentrations of up to 0.37 m3 m−3 and 0.18 m3 m−3, respectively, and is thus suitable for synthesis of fuels and chemicals. By adjusting the steam to carbon ratio, the syngas’ H2 to CO ratio can be purposely tailored by the water gas shift reaction for various synthesis products, e.g., synthetic natural gas (H2/CO = 3) or Fischer–Tropsch products (H2/CO = 2). Also, the composition and yields of fly ash and bed ash are presented. Through the gasification process, the cadmium and mercury contents of the bed ash were drastically reduced. The ash is suitable as secondary raw material for phosphorous or phosphate fertilizer production. Overall, a broad database was generated that can be used for process simulation and process design.
TL;DR: In this paper, the carbon footprint of synthetic natural gas production from biogas catalytic methanation was determined by means of the Global Warming potential impact in kg CO2-eq/kWh.
TL;DR: In this article, using a water-lean post-combustion capture solvent, [N-(2-ethoxyethyl)-3-morpholinopropan-1-amine] (2-EEMPA), >90 % conversion of captured CO2 to hydrocarbons, mostly methane, is achieved in the presence of a heterogenous Ru catalyst under relatively mild reaction conditions (170 °C and <15 bar H2 pressure).
Abstract: Integrated carbon capture and conversion of CO2 into materials (IC3 M) is an attractive solution to meet global energy demand, reduce our dependence on fossil fuels, and lower CO2 emissions. Herein, using a water-lean post-combustion capture solvent, [N-(2-ethoxyethyl)-3-morpholinopropan-1-amine] (2-EEMPA), >90 % conversion of captured CO2 to hydrocarbons, mostly methane, is achieved in the presence of a heterogenous Ru catalyst under relatively mild reaction conditions (170 °C and <15 bar H2 pressure). The catalytic performance was better in 2-EEMPA than in aqueous 5 m monoethanol amine (MEA). Operando nuclear magnetic resonance (NMR) study showed in situ formation of N-formamide intermediate, which underwent further hydrogenation to form methane and other higher hydrocarbons. Technoeconomic analyses (TEA) showed that the proposed integrated process can potentially improve the thermal efficiency by 5 % and reduce the total capital investment and minimum synthetic natural gas (SNG) selling price by 32 % and 12 %, respectively, compared to the conventional Sabatier process, highlighting the energetic and economic benefits of integrated capture and conversion. Methane derived from CO2 and renewable H2 sources is an attractive fuel, and it has great potential as a renewable hydrogen carrier as an environmentally responsible carbon capture and utilization approach.
TL;DR: In this article, the authors investigated the thermodynamics of methanation in a fluidized bed reactor for different product gas compositions of the dual fluidized-bed gasification technology.
Abstract: Natural gas is an important commodity in the European energy market. The gasification of biogenic residues and the further reaction to a methane-rich gas represent a promising concept for the production of synthetic natural gas on a fossil-free basis. This paper investigates the thermodynamics of methanation in a fluidized bed reactor for different product gas compositions of the dual fluidized bed gasification technology. The investigated product gases range from conventional steam gasification, over CO2 gasification, to product gases from the sorption enhanced reforming process. All investigated product gases from conventional steam gasification show an understoichiometric composition and therefore require a proper handling of carbon depositions and a CO2 separation unit downstream of the methanation reactor. The product gas from CO2 gasification is considered disadvantageous for the investigated process, because it only exhibits a carbon utilization efficiency of 23%. Due to the high flexibility of the sorption enhanced reforming process, a nearly complete methanation of the carbonaceous species is possible without the need for a CO2 separation step or the addition of steam upstream of the methanation reactor. Furthermore, the carbon utilization efficiency is found to be between 36 and 38%, similar to the results for conventional steam gasification. Temperature and pressure variations allow a thermodynamically optimized operation, which can increase the performance of the methanation and lower the extent of gas upgrading for grid feed-in. Additionally, if a higher hydrogen content in the natural gas grid would be allowed, the overall process chain could be further optimized and simplified.
TL;DR: In this paper, an analysis of the power-to-gas installation as an exemplary solution of a system storing excess electricity from renewable energy sources is presented, where the installation contains an integrated module of the electrolysis process, used for hydrogen production, hydrogen storage and a system for synthetic natural gas (SNG) production.
TL;DR: In this article, the CO2 methanation process, which yields synthetic natural gas (SNG) via the synthesis of CO2 and H2 through proton exchange membrane (PEM) water electrolysis using surplus electricity generated from renewable energy, was evaluated and optimized based on techno-economic analyses.
TL;DR: In this article, the authors show that the levelized cost of methane remains dominated by the cost of hydrogen until at least the middle of the century, but only if a carbon tax is levied of at least 270€/tCO2.
TL;DR: In this article, the design, construction and testing of a methanation reactor at laboratory scale to increase the knowledge of the key component of this system is presented, and experimental data are used to validate the theoretical kinetic model at different operating temperatures implemented in Aspen Plus.
TL;DR: In this article, the potentiality of Ni and NiFe supported biochar catalysts for CO2 methanation was evaluated, and the development of competitive biochar catalyst was found dependent on the creation of basic sites on the catalyst surface.
TL;DR: In this paper, the authors compared three hybrid systems for the production of synthetic natural gas (biomethane) from biogas or process gas, and calculated the carbon footprint of the three approaches using a streamlined life cycle assessment.
TL;DR: A detailed overview of bimetallic catalysts for CO methanation can be found in this article, which provides insights on how reaction effectiveness is enhanced, enabling catalyst development with the highest possible performance.
TL;DR: In this paper, the effects of integration manner of the Ni-Co components, Ni/Co mass ratio, and operating conditions on the catalytic performance were investigated for the conversion of syngas to SNG (CH4) and co-production of liquid fuels (C5+) over bimetallic NiCo catalysts at industrially relevant conditions.
TL;DR: In this article, the authors extend the reservoir simulator MUFITS for modeling flows in porous media related to these applications, such as the co-injection of natural gas, carbon dioxide, and other non-condensable gases into saline aquifers.
TL;DR: In this paper, the extrinsic and intrinsic interactions between catalytic gears (active metals, support materials, and promoters) have been investigated for carbon monoxide (CO) methanation.