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Showing papers on "Substitute natural gas published in 2007"


Journal ArticleDOI
TL;DR: In this paper, the authors compare greenhouse gas (GHG), SOx, and NOx life-cycle emissions of electricity generated with NG/LNG/SNG and coal and show that with the current fleet of power plants, a mix of domestic NG, LNG, and SNG would have lower GHG emissions than coal.
Abstract: The U.S. Department of Energy (DOE) estimates that in the coming decades the United States' natural gas (NG) demand for electricity generation will increase. Estimates also suggest that NG supply will increasingly come from imported liquefied natural gas (LNG). Additional supplies of NG could come domestically from the production of synthetic natural gas (SNG) via coal gasification−methanation. The objective of this study is to compare greenhouse gas (GHG), SOx, and NOx life-cycle emissions of electricity generated with NG/LNG/SNG and coal. This life-cycle comparison of air emissions from different fuels can help us better understand the advantages and disadvantages of using coal versus globally sourced NG for electricity generation. Our estimates suggest that with the current fleet of power plants, a mix of domestic NG, LNG, and SNG would have lower GHG emissions than coal. If advanced technologies with carbon capture and sequestration (CCS) are used, however, coal and a mix of domestic NG, LNG, and SNG ...

329 citations


Journal ArticleDOI
TL;DR: In this paper, it is suggested that atomic step sites play the important role as the active sites of the reaction and maintain the activity and stability of the catalyst after exposure to high temperatures.
Abstract: Manufacture of substitute natural gas (SNG) using high temperature methanation of synthesis gas is becoming important due to high energy prices, a wish for a stable energy supply, and diminishing natural gas in some areas. Maintaining the activity and stability of the catalyst after exposure to high temperatures is crucial for the process. At 600 °C, loss of active surface area proceeds via the atom migration sintering mechanism. The methanation reaction is structure sensitive and it is suggested that atomic step sites play the important role as the active sites of the reaction.

265 citations


Journal ArticleDOI
TL;DR: In this paper, the most promising skeletal nickel catalysts and Ru/C granular were tested in a continuously operating catalyst test rig, under demanding conditions (high feed concentrations, 10−20%wt%, and high space velocities, 2−34g organics ǫ(g catalyst Âh) −1 ) at 30-MPa and around 400°C.
Abstract: Catalyst stability and tolerance towards dissolved inorganics are the main challenges for successful hydrothermal gasification of wet biomass. A continuously operating catalyst test rig was built. Synthetic liquefied wood (phenol, anisole, ethanol, formic and acetic acid) was chosen to represent real biomass. After initial screening in a batch reactor, the most promising skeletal nickel catalysts and Ru/C granular were tested in the new rig, under demanding conditions (high feed concentrations, 10–20 wt%, and high space velocities, 2–34 g organics (g catalyst h) −1 ) at 30 MPa and around 400 °C. Skeletal nickel catalysts sintered rapidly but Ru/C was stable during 220 h of testing. The inorganic salt tolerance was examined by co-feeding Na 2 SO 4 . Ru/C deactivated over time; a possible mechanism was identified as irreversible sulfate bonding to Ru III being formed in the redox cycle of biomass gasification.

94 citations


Patent
24 Jul 2007
TL;DR: In this article, the carbonaceous material is first pyrolyzed, then subjected to steam reforming to produce a syngas, which is then passed to several clean-up steps then to a methanation zone to produce synthetic natural gas.
Abstract: The production of synthetic natural gas from a carbonaceous material, preferably a biomass material, such as wood. The carbonaceous material is first pyrolyzed, then subjected to steam reforming to produce a syngas, which is then passed to several clean-up steps then to a methanation zone to produce synthetic natural gas.

66 citations


Journal ArticleDOI
TL;DR: In this paper, a comprehensive life cycle-based ecological impact of synthetic natural gas (SNG) is investigated and compared with standard fuels delivering the same service (natural gas, fuel oil, petrol/diesel, and wood chips).
Abstract: A promising option to substitute fossil energy carriers by renewables is the production of synthetic natural gas (SNG) from wood, as this results in a flexible energy carrier usable via existing infrastructure in gas boilers or passenger cars. The comprehensive life cycle-based ecological impact of SNG is investigated and compared with standard fuels delivering the same service (natural gas, fuel oil, petrol/diesel, and wood chips). Life cycle impact assessment methodologies and external costs from airborne emissions provide measures of overall damage. The results indicate that the SNG system has the best ecological performance if the consumption of fossil resources is strongly weighted. Otherwise natural gas performs best, as its supply chain is energy-efficient and its use produces relatively low emissions. Wood systems are by far the best in terms of greenhouse gas emissions (GHG), where SNG emits about twice as much as the wood chips system. The main negative aspects of the SNG system are NOx and particulate emissions and the relatively low total energy conversion efficiency resulting from the additional processing to transform wood to gas. Direct wood combustion has a better ecological score when highly efficient particulate filters are installed. SNG performs better than oil derivatives with all the evaluation methods used. External costs for SNG are the lowest as long as GHG are valued high. SNG should preferably be used in cars, as the reduction of overall ecological impacts and external costs when substituting oil-based fuels is larger for current cars than for heating systems.

58 citations


Journal ArticleDOI
TL;DR: In this article, the onset of the gasification reaction was visualized in sealed quartz capillaries as high pressure batch reactors, by using an optical microscope, and the onset temperature was found around 250 °C, which was much lower than conventional atmospheric gasification processes operating at 800-900 °C.

48 citations


Journal ArticleDOI
TL;DR: The yield of bio-oil from pyrolysis of the samples increased with temperature, while the bio-char yield decreased with increasing particle size of the sample in this article.
Abstract: Bio-fuels, such as bio-oil, bio-char, and bio-gas, can be obtained from agricultural residues. Agricultural residues are potential renewable energy resources such as biogas from anaerobic digestion, bio-oil from pyrolysis, and bio-char from carbonization and slow pyrolysis processes. Pyrolysis process of agricultural residues are the most common and convenient methods for conversion into bio-oil and bio-char. When the pyrolysis temperature increased, the bio-char yield decreased. The bio-char yield increased with increasing particle size of the sample. The yield of bio-oil from pyrolysis of the samples increased with temperature. Anaerobic biogas production is an effective process for conversion of a broad variety of agricultural biomass to methane to substitute natural gas and medium calorific value gases.

45 citations


DissertationDOI
01 Jan 2007
TL;DR: In this paper, the authors propose a method to solve the problem of "uniformity" and "uncertainty" in the context of health care, and propose a solution.
Abstract: xiii

36 citations


Journal ArticleDOI
01 Oct 2007-Energy
TL;DR: In this paper, the economic conditions under which new biomass technologies become competitive were assessed with the cost optimization model SWISS-MARKAL (MARKet ALlocation) with a focus on the production of synthetic natural gas (bio-SNG) from wood in a methanation plant.

33 citations


DissertationDOI
01 Jan 2007
TL;DR: In this article, the authors presented an experimental campaign with a slipstream of the FICFB-gasifier (Fast Internally Circulating Fluidized Bed) in Gussing (Austria) in 2003.
Abstract: Rising prices for fossil fuels and concerns over the climate change increase the interest in renewable energies. Synthetic natural gas (SNG) can be an option, filling the request for alternatives in the transportation sector, where the dependence on the oil is very strong. The advantages of synthetic natural gas (SNG) as fuel are the high energy density, the clean combustion and the already existing natural gas distribution grid. The perspective for a realization in the near future of an industrial size SNG production from biomass is promising as already a sound scientific basis for the methane synthesis exists. In the 70`s and 80`s of the last century methanation of synthesis gas was investigated intensely. At that time coal gasification and synthesis of SNG was considered as a possibility to increase the security of energy supply. With the participation of PSI, a project team was set up that has the vision to realize a first 20 MW plant converting “Wood to SNG” until the end of this decade. A systems analysis identified key issues, for the optimization of the combination of gasification technology and fuel synthesis. Calculations using ASPENPLUS®, furthermore, showed the expected chemical efficiency from wood to SNG to be in the range of 60 to 65% and determined promising operation conditions for the experimental campaigns. State of the art for the methane synthesis from producer gas is a multistage fixed bed process. To control the reaction conditions and to avoid catalyst deactivation by carbon deposition, tar reforming, water gas shift and methanation reaction are performed in different operation units. Goal of the technology development is an efficient synthesis process for SNG from biogenic producer gases, which is economically attractive. From literature it is known, that fluidization of the catalyst has a regenerating effect, limiting the carbon deposition. Based on fluidized bed technology, a once through SNG synthesis concept was developed incorporating tar reforming, water gas shift and methanation in a single fluidized bed. To proof the reactor concept, a lab scale fluidized bed methanation system was constructed. After several preliminary tests, an experimental campaign was performed with a slipstream of the FICFB-gasifier (Fast Internally Circulating Fluidized Bed) in Gussing (Austria) in 2003. The producer gas of this industrial 8 MWth gasification power plant with a H2/CO ratio of 1.4 and a content of light tars (Benzene, Toluene, Naphthalene, etc.) in the order of several g/m3 is used to run a gas engine which has an output of 2 MWel. As the producer gas is nearly nitrogen-free but methane-rich it is also considered as very suitable for methanation. During this campaign, the methanation catalyst was tested using three different gas cleaning strategies. The campaign started with an additional cleanup, consisting of an ammonia scrubber, an active carbon filter and a ZnO bed for desulphurization. Stepwise, the active carbon filter and ammonia scrubber were removed form the cleaning system. At the end of the campaign the gas cleaning for the methanation catalyst consisted only of the existing product gas cleaning of the power plant and a ZnO bed. During this campaign the catalyst was in operation for 120 h. Under the final conditions without additional cleaning, more than 98% CO conversion and 99% tar conversion was achieved resulting in an overall chemical efficiency of 63%. The experiences gained in this campaign and the promising results set the basis for the construction of a 10 kW mini pilot. The new test rig was designed for unmanned operation, needed to perform on-site long-duration experiments. The setup was commissioned in summer 2004 and tested with synthetic product gas for promising operation conditions. Finally, a 100 h test was performed as a preparation for the on-site experiments in Guessing. In September 2004, the setup was transferred to Guessing and linked to the FICFB gasifier. Until the end of 2004, two 200 h long duration experiments in Guessing were performed. Results from the campaign 2003 could successfully be reproduced. A second proof of concept could be done. The results are encouraging even though the catalyst deactivated after 200 hours, probably due to a combination of carbon deposition and sulphur poisoning by organic sulphur species. In the last part of the thesis, we concentrated on the carbon exchange processes in the fluidized bed, facilitating the methanation with integrated WGS and reforming, and limiting the rate carbon deposition. By means of in-situ measurements of the axial gas phase concentration profiles with a moveable sampling probe, strong carbon exchange processes between the catalyst and the gas phase were shown. These exchange processes structure the bed into three zones: Carbon deposition, predominantly by CO dissociation, at the inlet; predominant gasification of solid carbon species from the catalyst in the following zone, and predominant carbon deposition by methane dissociation in the upper part of the bed. By analyzing the carbon balance, locally up to 20 % excess carbon was found in the gas phase, mainly in form of methane. Due to an intensive catalyst mixing, the build-up of unreactive carbon is prevented by regeneration in the middle zone of the reactor. The result of the two campaigns (2003 and 2004) was the technical basis for an EU project within the 6th Framework program of DG-TREN. Within this project a 1 MW SNG process development unit (PDU) will be erected and operated. The project started May 2006.

21 citations


Journal ArticleDOI
01 Aug 2007-Energy
TL;DR: In this article, a combined cycle with synthetic utilization of coal and natural gas is proposed, in which the burning of coal provides thermal energy to the methane/steam reforming reaction, and the syngas fuel generated by the reforming reaction is directly provided to the gas turbine as fuel.

Patent
28 Feb 2007
TL;DR: In this paper, a method for producing natural gas with coking gas, comprising the following steps: purifying coking gases and removing benzene, naphthalene, hydrocarbon and sulphide, compressing, heat transferring, carrying out methanation reaction with catalyst, hydrogen in COG reacting with carbonic oxide and carbon dioxide to get methane; putting the mixture gas into pressure swing adsorbing device, and getting natural gas whose concentration is 90%.
Abstract: The invention discloses the method for producing natural gas with coking gas, comprising the following steps: purifying coking gas and removing benzene, naphthalene, hydrocarbon and sulphide, compressing, heat transferring, carrying out methanation reaction with catalyst, hydrogen in COG reacting with carbonic oxide and carbon dioxide to get methane; putting the mixture gas into pressure swing adsorbing device, and getting natural gas whose concentration is 90%. The natural gas has high caloric value, low impurity content.

Patent
08 Feb 2007
TL;DR: In this article, a system and method for producing substitute natural gas and electricity, while mitigating production of any greenhouse gasses is presented, which includes a hydrogasification reactor, to form a gas stream including natural gas, a char stream, and an oxygen burner to combust the char material to form carbon oxides.
Abstract: The present invention provides a system and method for producing substitute natural gas and electricity, while mitigating production of any greenhouse gasses. The system includes a hydrogasification reactor, to form a gas stream including natural gas and a char stream, and an oxygen burner to combust the char material to form carbon oxides. The system also includes an algae farm to convert the carbon oxides to hydrocarbon material and oxygen.

Patent
08 Feb 2007
TL;DR: In this paper, a system and method for producing substitute natural gas and electricity, while mitigating production of any greenhouse gasses is presented, which includes a hydrogasification reactor, to form a gas stream including natural gas, a char stream, and an oxygen burner to combust the char material to form carbon oxides.
Abstract: The present invention provides a system and method for producing substitute natural gas and electricity, while mitigating production of any greenhouse gasses. The system includes a hydrogasification reactor, to form a gas stream including natural gas and a char stream, and an oxygen burner to combust the char material to form carbon oxides. The system also includes an algae farm to convert the carbon oxides to hydrocarbon material and oxygen.


Journal ArticleDOI
TL;DR: In this article, a survey of processes for manufacturing synthetic liquid fuels on the basis of Fischer-Tropsch synthesis from alternative feedstock (natural gas, coal, biomass of various origins, etc.) is presented.
Abstract: Processes for manufacturing synthetic liquid fuels on the basis of the Fischer-Tropsch synthesis from alternative feedstock (natural gas, coal, biomass of various origins, etc.) are surveyed. State-of-the-art technology, companies that offer such processes, and the quality of products in comparison with their oil analogs, as well as economic features of the processes, are considered.

Journal Article
Lou Diming1
TL;DR: In this article, the authors established the life cycle energy consumption and environment emission assessment model of conventional gasoline and its alternative fuels and proposed a life cycle and environment assessment model for conventional gasoline.
Abstract: Life cycle energy consumption and environment emission assessment model of conventional gasoline and its alternative fuels is established in this paper.And,external cost of net energy yield(ECNEY),an indictor to link life cycle energy consumption and environmental pollutant emissions of conventional gasoline,ethanol,methanol,liquefied petroleum gas(LPG),liquefied natural gas(LNG) and compressed natural gas(CNG),is put forward.Then,life cycle energy and environment assessment of conventional gasoline and its alternative fuels is made.Compared with conventional gasoline,ethanol(from wheat,maize,and cassava) and methanol from coal achieve higher ECNEY,whereas,methanol from natural gas,LPG,LNG,and CNG achieve lower ECNEY.From the perspective of reducing ECNEY,methanol from natural gas,LPG,LNG,and CNG are proposed to be chosen first as gasoline alternative fuels in China.

Patent
09 Jan 2007
TL;DR: In this paper, an entrained flow gasifier is used to produce synthetic natural gas through a direct reaction between hydrogen/steam and coal without using a catalyst, and to minimize the generation of hydrogen and carbon monoxide.
Abstract: Provided is a hydrogen gasifying reaction apparatus of coal to produce synthetic natural gas through a direct reaction between hydrogen/steam and coal without using a catalyst, and to minimize the generation of hydrogen and carbon monoxide. The hydrogen gasifying reaction apparatus of coal for production of synthetic natural gas is constituted by an entrained flow gasifier(17) where a hydrogen/steam gasifying reaction occurs, compressed gas input units(7,14), a compressed steam input unit(3), a compressed coal input unit(11), non-incinerated residue and ash collection units(22,24,26), and a gas analyzer(20). To control concentration of hydrogen and pressure of a reactor, nitrogen and helium gas(12) are directly injected to the gasifier(17) through pressure controllers(6,13). If the pressure of the gasifier(17) is higher than a certain value, a signal is sent to automatic valves(4,8,15,18,25) so as to stop the gas injection or to release the gas into outside.

Journal Article
Han Weijian1
TL;DR: In this paper, a well-to-wheel analysis was used to accurately evaluate the energy use and global warming impact of the production and utilization of natural gas and coal-based vehicle fuels in China.
Abstract: Well-to-Wheel analyses are used to accurately evaluate the energy use and global warming impact of the production and utilization of natural gas and coal-based vehicle fuels in China. The Well-to-Wheel analysis predicts the energy use and greenhouse gases emissions due to recovery, production, transport, and distribution of the methanol, dimethyl ether, and Fischer-Tropsch diesel (FTD) fuels. The results are compared with traditional gasoline and diesel fuels. The results show that natural gas and coal-based methanol, DME, and F-T diesel fuels have lower lifecycle petroleum consumption than traditional gasoline and diesel fuels, so they may be enhance China’s oil security. The lifecycle total energy use, fossil energy use, and greenhouse gas emission of natural gas-based fuels are lower than those of coal-based fuels, but higher than traditional gasoline and diesel, so utilization of natural gas-based fuels will lead to potential pressure to reduce China’s greenhouse gas emissions.

01 Jan 2007
TL;DR: The observance of local and technical basic conditions is one of the main subjects associated with designing a SNG (substitute natural gas) plant based on the gasification of biomass feedstock as discussed by the authors.
Abstract: The observance of local and of technical basic conditions is one of the main subjects associated with designing a SNG (substitute natural gas) plant based on the gasification of biomass feedstock. Amongst others the local basic conditions comprise the kind of biomass to be gasified, its local and seasonal availability, the haul distance of educts and products to and from the gasification plant and above all the possibilities to use the process heat. Mainly dry lignin containing biomass like wood is the most suitable biomass for thermal gasification. For other biomasses, especially for those with a high water content, SNG production by fermentation is preferable. Furthermore, a high energy density of biomass is desirable because the collection and transportation of biomass with a low energy density is coupled with a high consumption of energy. This is one of the main reasons for choosing wood as a feedstrock because its energy density with about 6500 MJ/m3 is much higher than for example for straw with about 1000 MJ/m3. For the technical aspects of gasification the selection of the most suitable gasification process, of the process temperature and the process pressure are determined by the properties of the chosen biomass (e.g. water content, grain size, contents of ash, chlorine, sulphur and of other trace components). Finally all the requirements of the relevant DVGW-regulations (above all of G 260 and G 262) have to be fulfilled.

ReportDOI
31 May 2007
TL;DR: The Advanced Hydrogasification Process (AHP) as mentioned in this paper was developed through NETL with a DOE Grant and has successfully completed its first phase of development and has shown promising potential.
Abstract: The Advanced Hydrogasification Process (AHP)--conversion of coal to methane--is being developed through NETL with a DOE Grant and has successfully completed its first phase of development. The results so far are encouraging and have led to commitment by DOE/NETL to begin a second phase--bench scale reactor vessel testing, expanded engineering analysis and economic perspective review. During the next decade new means of generating electricity, and other forms of energy, will be introduced. The members of the AHP Team envision a need for expanded sources of natural gas or substitutes for natural gas, to fuel power generating plants. The initial work the team has completed on a process to use hydrogen to convert coal to methane (pipeline ready gas) shows promising potential. The Team has intentionally slanted its efforts toward the needs of US electric utilities, particularly on fuels that can be used near urban centers where the greatest need for new electric generation is found. The process, as it has evolved, would produce methane from coal by adding hydrogen. The process appears to be efficient using western coals for conversion to a highly sought after fuel with significantly reduced CO{sub 2} emissions. Utilities have a natural interest in the preservation of their industry, which will require a dramatic reduction in stack emissions and an increase in sustainable technologies. Utilities tend to rank long-term stable supplies of fuel higher than most industries and are willing to trade some ratio of cost for stability. The need for sustainability, stability and environmentally compatible production are key drivers in the formation and progression of the AHP development. In Phase II, the team will add a focus on water conservation to determine how the basic gasification process can be best integrated with all the plant components to minimize water consumption during SNG production. The process allows for several CO{sub 2} reduction options including consumption of the CO{sub 2} in the original process as converted to methane. The process could under another option avoid emissions following the conversion to SNG through an adjunct algae conversion process. The algae would then be converted to fuels or other products. An additional application of the algae process at the end use natural gas fired plant could further reduce emissions. The APS team fully recognizes the competition facing the process from natural gas and imported liquid natural gas. While we expect those resources to set the price for methane in the near-term, the team's work to date indicates that the AHP process can be commercially competitive, with the added benefit of assuring long-term energy supplies from North American resources. Conversion of coal to a more readily transportable fuel that can be employed near load centers with an overall reduction of greenhouses gases is edging closer to reality.

01 Jan 2007
TL;DR: In this article, the optimal design of thermochemical fuel production processes with respect to its environomic (energetic, economic and environmental) performance is addressed, and a multi-objective optimisation algorithm is proposed to target the best process technology and operating conditions for the trigeneration of fuels, heat and power.
Abstract: Transport applications are a major global source of greenhouse gas emissions and the production of fuels that are renewable and neutral in CO2 is an important issue in chemical process research and development. Contrary to the biological routes that produce bioethanol and -diesel on industrial scale through fermentation or esterification, 2nd generation biofuels obtained through thermochemical processing of lignocellulosic and waste biomass by means of gasification and fuel reforming are expected to be truly sustainable since high conversion efficiencies and a decidedly positive environmental balance are achieved. The poster addresses the optimal design of such thermochemical fuel production processes with respect to its environomic (energetic, economic and environmental) performance. Thereby, the challenge is to develop design methodologies that allow the identification of the most promising conversion routes in a specific environmental and economical context. Thermo-economic process modelling and integration techniques are coupled with a multi-objective optimisation algorithm to target the best process technology and operating conditions for the trigeneration of fuels, heat and power. The approach is demonstrated on the production of synthetic natural gas from wood considering different gasification technologies and the possibility to increase the fuel yield from biomass and electrical power by integrating an electrolyser in the system.

Journal ArticleDOI
TL;DR: In this paper, three IGCC-power plant concepts for central production of a hydrogen-rich fuel (methanol, hydrogen, synthetic natural gas? SNG) from lignite are presented.
Abstract: This paper presents three IGCC-power plant concepts for central production of a hydrogen-rich fuel (methanol, hydrogen, synthetic natural gas ? SNG) from lignite. Each concept contains a CO2-separation, which produces a sequestration-ready CO2-rich stream. Thus, CO2-emissions caused by use of lignite are considerably reduced. Furthermore, the produced low-carbon fuels are converted in decentralised Combined Heat and Power Plants (CHPP). CHPP leads to high efficiencies of fuel utilisation between 54 and 62%, which exceed the efficiencies of single power generation. Regarding to the CO2-emissions of a natural gas fired CHPP, heat and power can be generated by lignite as clean as by natural gas. The specific CO2-emissions are even much lower in the case of hydrogen production. Costs for the centrally produced methanol and hydrogen are with 29 and 19 EUR/MWh(LHV) already within an economic range. Synthetic natural gas can be produced for 23 EUR/MWh(LHV).

Patent
14 Mar 2007
TL;DR: One kind of synthetic natural gas producing process is disclosed in this paper, where CO2 is separated out from marsh gas material by means of the difference in smelting point and boiling point between CO2 and methane, chemical adsorption and other methods.
Abstract: One kind of synthetic natural gas producing process is disclosed. Marsh gas is used as material in producing synthetic natural gas, and after CO2 is separated out from marsh gas material by means of the difference in smelting point and boiling point between CO2 and methane, chemical adsorption and other methods, synthetic natural gas with high content of methane may be obtained. The synthetic natural gas producing process has low cost and is clean and environment friendly.