Showing papers on "Substitute natural gas published in 2006"

Biogas Potential of Manure and Straw Mixtures

Abstract: Wheat straw or manure or both were converted to a methane-rich gas mixture. Anaerobic biomethane production is an effective process for conversion of a broad variety of lignocellulosic materials to methane to substitute natural gas and medium calorific value gases. Methane generating bacteria (methanogens) and other microbes help digest dying plants in anaerobic (without oxygen) conditions. Wheat straw wastes represent a potential energy resource if they can be properly and biologically converted to methane. The yields of methane from the materials used were found between 10.4% and 14.7%. The producing gas has an energy content of about 33%–50% of the higher heating value from the feedstock. The most important parameters for the biogas generation rates were the total solids (TS) concentration in the slurry, the digestion time, species of feeding substrate, and pH of the medium. The methane content of the biogas was in the range of 73%–79% for the runs, the remainder being principally carbon dioxide.

Production of Synthetic Natural Gas (SNG) from biomass development and operation of an integrated bio-SNG system non-confidential version

Abstract: The substitution of natural gas by a renewable equivalent is an interesting option to reduce the use of fossil fuels and the accompanying greenhouse gas emissions, as well as from the point of view of security of supply. The renewable alternative for natural gas is the so-called green natural gas, i.e. gaseous energy carriers produced from biomass comprising both biogas and Synthetic Natural Gas (SNG). Via this route can be benefited from all the advantages of natural gas, like the existing dense infrastructure, trade and supply network, and natural gas applications. To implement green natural gas in the Dutch energy infrastructure a phased approach is suggested. On the short term is started with the route of upgraded biogas produced by biological digestion of biomass materials like manure. The main source of green natural gas on the long term, however, will be synthetic natural gas (SNG) that is produced via gasification of biomass and subsequent methanation of the product gas. The potential for natural gas substitution by SNG is in fact 100%, a potential limitation might be set by the requirement for large amounts of biomass. In order to demonstrate that this bio-SNG can comply (at least after blending) with these specifications, an experimental bench-scale line-up for SNG production from biomass has been developed and implemented, consisting of a biomass gasifier and several gas cleaning and conditioning steps.

"green gas" as sng (synthetic natural gas) a renewable fuel with conventional quality

Abstract: ”Green Gas” as SNG (Synthetic Natural Gas) can play an important role in the transition process from the present Dutch fossil fuel-based energy supply to a renewable fuel-based economy. Anaerobic digestion and supercritical water gasification have been assessed for SNG production from wet biomass streams. For relatively dry biomass streams steam-blown indirect gasification, pressurised oxygenblown gasification, hydrogasification, and co-production of both Fischer-Tropsch diesel and SNG have been considered. All cases with upstream gasification are followed, after gas cleanup, by a downstream methanation step. Although upgrading of landfill gas, or biogas produced via anaerobic digestion of wet biomass, will be interesting for the short-term introduction of “Green Gas” in the Dutch energy supply, the supercritical water gasification processes seem to be more promising for conversion of wet biomass to “Green Gas” on the longer term. Based on the modelling results, the upstream-pressurised oxygen-blown CFB and indirect atmospheric steam-blown gasification with downstream methanation routes were identified to be the most promising options for stand-alone SNG production from relatively dry biomass feedstocks. In combination with downstream methanation, SNG production efficiencies up to 70% (LHV) can be achieved. The successful integrated lab-scale demonstration of “Green Gas” production confirmed the potential of the ECN gas cleanup concept to deliver a product gas that can satisfy, among others, the specifications for downstream methanation. For 100 MWth stand-alone systems and biomass costs of 2.3 €/GJwood, the SNG production costs range from 7.8 to 8.5 €/GJSNG and the CO2 emission reduction costs range from 83 to 95 €/tonne. “Green Gas” production via biomass gasification with downstream methanation will become an economic feasible process in the Netherlands, when “Green Gas” receives the same tax exemptions as currently are given to green electricity.

수소가스화기에서 석탄의 메탄화 반응 특성

Abstract: To investigate the characteristics of substitute natural gas (SNG) production from direct coal methanation, the continuous lab-scale entrained flow hydrogasifier (I.D. : 0.025 m, Height : 1.0 m) was used in this experiment. The hydrogasification system consisted of high pressure gas handling system, high pressure coal feeder, entrained flow hydrogasifier, and unreacted char separator. The experiment was performed at the various conditions of reaction temperature (600~800 oC), H2/coal ratio (0.2~0.4), and coal feed rate (0.8~2.5 g/min). Although it was shown that carbon conversion was different trends with coals from the methanation results for 6 sample coals, the carbon conversion increased with increasing reaction temperature. And it increased with increasing H2/coal ratio, whereas the concentration of CH4 decreased. Also. the carbon conversion increased with the carbon content of coal sample and had a maximum value at volatile matter content of 35 wt.

Browngas blend substitute gas

Abstract: A hydrogen/oxygen blend substitute gas is provided to supply a brown gas by mixing hydrogen and oxygen with the 2:1 ratio, thereby enhancing the use efficiency as the regeneration energy. The brown gas of 1-99% is mixed with LNG(Liquefied Natural Gas) and SNG(Substitute Natural Gas) as the existing fossil fuels. The substitute gas mixed with the brown gas is used for the city gas, the industrial gas fuel and a gas engine, a gas turbine and the steam supply and power generation. The substitute gas has the rapid combustion property and the wide combustion range due to the wide inflammable limitation so that the harmful air pollution materials are reduced.