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Gasification is a process that converts carbonaceous materials, such as coal, petroleum, or biomass, into carbon monoxide and hydrogen by reacting the raw material at high temperatures with a controlled amount of oxygen. The resulting gas mixture is called synthesis gas or syngas and is itself a fuel. Gasification is a very efficient method for extracting energy from many different types of organic materials, and also has applications as a clean waste disposal technique. Image File history File links Sustainable_development. ... The gasogene (or seltzogene) was a late Victorian device for producing carbonated water. ... Coal Example chemical structure of coal Coal (pronounced ) is a fossil fuel formed in swamp ecosystems where plant remains were saved by water and mud from oxidization and biodegradation. ... Petro redirects here. ... For the use of the term in ecology, see Biomass (ecology). ... R-phrases , , , , S-phrases , , , , Flash point Flammable gas Related Compounds Related oxides carbon dioxide; carbon suboxide; dicarbon monoxide; carbon trioxide Supplementary data page Structure and properties n, εr, etc. ... This article is about the chemistry of hydrogen. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colourless (gas) colourless (liquid) Standard atomic weight 15. ... Syngas (from synthesis gas) is the name given to gasses of varying composition that are generated in coal gasification and some types of waste-to-energy facilities. ... It has been suggested that Town gas be merged into this article or section. ... Waste management is literally the process of managing waste materials (normally those produced as a result of human activities). ...

The advantage of gasification is that using the syngas is more efficient than direct combustion of the original fuel; more of the energy contained in the fuel is extracted. Syngas may be burned directly in internal combustion engines, used to produce methanol and hydrogen, or converted via the Fischer-Tropsch process into synthetic fuel. Gasification can also begin with materials that are not otherwise useful fuels, such as biomass or organic waste. In addition, the high-temperature combustion refines out corrosive ash elements such as chloride and potassium, allowing clean gas production from otherwise problematic fuels. It has been suggested that Town gas be merged into this article or section. ... It has been suggested that Town gas be merged into this article or section. ... Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naptha or wood spirits, is a chemical compound with chemical formula CH3OH. It is the simplest alcohol, and is a light, volatile, colourless, flammable, poisonous liquid with a distinctive odor that is somewhat milder and sweeter than ethanol (ethyl alcohol). ... This article is about the chemistry of hydrogen. ... // The Fischer-Tropsch process is a catalyzed chemical reaction in which carbon monoxide and hydrogen are converted into liquid hydrocarbons of various forms. ... Synthetic fuel or synfuel is any liquid fuel obtained from coal, natural gas, or biomass. ... For the use of the term in ecology, see Biomass (ecology). ... Organic may refer to: Look up organic in Wiktionary, the free dictionary. ...

Gasification of fossil fuels is currently widely used on industrial scales to generate electricity. However, almost any type of organic material can be used as the raw material for gasification, such as wood, biomass, or even plastic waste. Thus, gasification may be an important technology for renewable energy. In particular biomass gasification is carbon neutral. Fossil fuels are hydrocarbon-containing natural resources such as coal, petroleum and natural gas. ... Electricity (from New Latin Ä“lectricus, amberlike) is a general term for a variety of phenomena resulting from the presence and flow of electric charge. ... Organic may refer to: Look up organic in Wiktionary, the free dictionary. ... For other uses, see Wood (disambiguation). ... For the use of the term in ecology, see Biomass (ecology). ... For other uses, see Plastic (disambiguation). ... Renewable energy effectively utilizes natural resources such as sunlight, wind, tides and geothermal heat, which are naturally replenished. ... For the use of the term in ecology, see Biomass (ecology). ... A carbon audit regime is an effective means of accounting for greenhouse gas control efforts. ...

Gasification relies on chemical processes at elevated temperatures >700°C, which distinguishes it from biological processes such as anaerobic digestion that produce biogas. Anaerobic digestion component of Lübeck mechanical biological treatment plant in Germany, 2007 Anaerobic digestion is a process in which microorganisms break down biodegradable material in the absence of oxygen. ... Biogas-bus in Bern, Switzerland Biogas typically refers to a (biofuel) gas produced by the anaerobic digestion or fermentation of organic matter including manure, sewage sludge, municipal solid waste, biodegradable waste or any other biodegradable feedstock, under anaerobic conditions. ...

Chemistry

In a gasifier, the carbonaceous material undergoes several different processes:

Pyrolysis of carbonaceous fuels

Gasification of char

1. The pyrolysis (or devolatilization) process occurs as the carbonaceous particle heats up. Volatiles are released and char is produced, resulting in up to 70% weight loss for coal. The process is dependent on the properties of the carbonaceous material and determines the structure and composition of the char, which will then undergo gasification reactions.
2. The combustion process occurs as the volatile products and some of the char reacts with oxygen to form carbon dioxide and carbon monoxide, which provides heat for the subsequent gasification reactions. Letting C represent a carbon-containing organic compound, the basic reaction here is
3. The gasification process occurs as the char reacts with carbon dioxide and steam to produce carbon monoxide and hydrogen, via the reaction
4. In addition, the reversible gas phase water gas shift reaction reaches equilibrium very fast at the temperatures in a gasifier. This balances the concentrations of carbon monoxide, steam, carbon dioxide and hydrogen.

In essence, a limited amount of oxygen or air is introduced into the reactor to allow some of the organic material to be "burned" to produce carbon monoxide and energy, which drives a second reaction that converts further organic material to hydrogen and additional carbon monoxide. Image File history File links Pyrolysis. ... Image File history File links Gasification. ... Simple sketch of pyrolysis chemistry Pyrolysis usually means the chemical decomposition of organic materials by heating in the absence of oxygen or any other reagents, except possibly steam. ... Charring is a process of incomplete combustion that often occurs when biological tissue (living or dead) is subjected to heat. ... This article is about the chemical reaction combustion. ... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... R-phrases , , , , S-phrases , , , , Flash point Flammable gas Related Compounds Related oxides carbon dioxide; carbon suboxide; dicarbon monoxide; carbon trioxide Supplementary data page Structure and properties n, εr, etc. ... Organic may refer to: Look up organic in Wiktionary, the free dictionary. ... A reversible reaction is a chemical reaction that may proceed in both the forward and reverse directions. ... The water gas shift reaction is an organic reaction in which water and carbon monoxide react to form carbon dioxide and hydrogen (water splitting) CO + H2O → CO2 + H2 The water gas shift reaction is part of steam reforming of hydrocarbons and is involved in the chemistry of catalytic converters While... A burette, an apparatus for carrying out acid-base titration, is an important part of equilibrium chemistry. ... R-phrases , , , , S-phrases , , , , Flash point Flammable gas Related Compounds Related oxides carbon dioxide; carbon suboxide; dicarbon monoxide; carbon trioxide Supplementary data page Structure and properties n, εr, etc. ... This article is about the chemistry of hydrogen. ... R-phrases , , , , S-phrases , , , , Flash point Flammable gas Related Compounds Related oxides carbon dioxide; carbon suboxide; dicarbon monoxide; carbon trioxide Supplementary data page Structure and properties n, εr, etc. ...

History

The gasification process was originally developed in the 1800s to produce town gas for lighting and cooking. Natural gas and electricity later replaced town gas for these applications, but the gasification process has been utilized for the production of synthetic chemicals and fuels since the 1920s. Town gas is a generic term referring to manufactured gas produced for sale to consumers and municipalities. ...

Wood gas generators, called Gasogene or Gazogène, were used to power motor vehicles in Europe during World War II fuel shortages.^[1] Wood gas generator schematic Wood gasifier on a Ford truck converted to a tractor (an EPA tractor). ... For other uses, see Europe (disambiguation). ... Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000...

Current applications

Industrial-scale gasification is currently mostly used to produce electricity from fossil fuels such as coal, where the syngas is burned in a gas turbine. Fossil fuels are hydrocarbon-containing natural resources such as coal, petroleum and natural gas. ... Coal Example chemical structure of coal Coal (pronounced ) is a fossil fuel formed in swamp ecosystems where plant remains were saved by water and mud from oxidization and biodegradation. ... It has been suggested that Town gas be merged into this article or section. ... This machine has a single-stage centrifugal compressor and turbine, a recuperator, and foil bearings. ...

Gasification is also used industrially in the production of electricity, ammonia and liquid fuels (oil) using Integrated Gasification Combined Cycles (IGCC), with the possibility of producing methane and hydrogen for fuel cells. IGCC is also a more efficient method of CO₂ capture as compared to conventional technologies. IGCC demonstration plants have been operating since the early 1970s and some of the plants constructed in the 1990s are now entering commercial service. Combined cycle is a term used when a power producing engine or plant employs more than one thermodynamic cycle. ... Methane is a chemical compound with the molecular formula . ... This article is about the chemistry of hydrogen. ...

Within the last few years, gasification technologies have been developed that use plastic-rich waste as a feed. In a plant in Germany such a technology—on large scale—converts plastic waste via syngas into methanol.^[2] For other uses, see Plastic (disambiguation). ... It has been suggested that Town gas be merged into this article or section. ... Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naptha or wood spirits, is a chemical compound with chemical formula CH3OH. It is the simplest alcohol, and is a light, volatile, colourless, flammable, poisonous liquid with a distinctive odor that is somewhat milder and sweeter than ethanol (ethyl alcohol). ...

Small-scale rural biomass gasifiers have been applied in India to a large extent, especially in the state of Tamil-Nadu in South India. Most of the applications are 9 kWe systems used for (drink) water pumping and street lighting operated by the local panchayat government. Although technically applicable the systems do face a number of problems. There are political, financial and maintenance problems. Most of the systems are no longer running after 1...3 years. , Tamil Nadu (Tamil: தமிழ்நாடு,   English: , IPA: ) is one of the 28 states of India. ... // The Panchayat (पंचायत in Devanagiri) is an Indian political system that groups five villages in a quincunx (four peripheral villages around a central one were laid out as the 5 side of a die). ...

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== Potential for renewable energy ==

Gasification can proceed from just about any organic material, including biomass and plastic waste. The resulting syngas burns cleanly into water vapor and carbon dioxide. Alternatively, syngas may be converted efficiently to methane via the Sabatier reaction, or diesel-like synthetic fuel via the Fischer-Tropsch process. Inorganic components of the input material, such as metals and minerals, are trapped in an inert and environmentally safe form as ash, which may have use as a fertilizer. Organic may refer to: Look up organic in Wiktionary, the free dictionary. ... For the use of the term in ecology, see Biomass (ecology). ... For other uses, see Plastic (disambiguation). ... It has been suggested that Town gas be merged into this article or section. ... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... It has been suggested that Town gas be merged into this article or section. ... Methane is a chemical compound with the molecular formula . ... The Sabatier process involves the reaction of hydrogen with carbon dioxide at elevated temperatures and pressures in the presence of a nickel catalyst to produce methane and water. ... Synthetic fuel or synfuel is any liquid fuel obtained from coal, natural gas, or biomass. ... // The Fischer-Tropsch process is a catalyzed chemical reaction in which carbon monoxide and hydrogen are converted into liquid hydrocarbons of various forms. ...

Regardless of the final fuel form, gasification itself and subsequent processing neither emits nor traps greenhouse gasses such as carbon dioxide. Combustion of syngas or derived fuels does of course emit carbon dioxide. However, biomass gasification could play a significant role in a renewable energy economy, because biomass production removes CO₂ from the atmosphere. While other biofuel technologies such as biogas and biodiesel are also carbon neutral, gasification runs on a wider variety of input materials, can be used to produce a wider variety of output fuels, and is an extremely efficient method of extracting energy from biomass. Top: Increasing atmospheric CO2 levels as measured in the atmosphere and ice cores. ... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... For the use of the term in ecology, see Biomass (ecology). ... Renewable energy effectively utilizes natural resources such as sunlight, wind, tides and geothermal heat, which are naturally replenished. ... For the use of the term in ecology, see Biomass (ecology). ... For articles on specific fuels used in vehicles, see Biogas, Bioethanol, Biobutanol, Biodiesel, and Straight vegetable oil. ... Biogas-bus in Bern, Switzerland Biogas typically refers to a (biofuel) gas produced by the anaerobic digestion or fermentation of organic matter including manure, sewage sludge, municipal solid waste, biodegradable waste or any other biodegradable feedstock, under anaerobic conditions. ... This article is about transesterified plant and animal oils. ... A carbon audit regime is an effective means of accounting for greenhouse gas control efforts. ...

Biomass gasification is therefore one of the most technically and economically convincing energy possibilities for a carbon neutral economy ^[3] A carbon audit regime is an effective means of accounting for greenhouse gas control efforts. ...

There is at present very little industrial scale biomass gasification being done. The Renewable Energy Network Austria^[4] is associated with several successful biomass gasification demonstration projects, including a plant using dual fluidized bed gasification^[5] that has supplied the town of Güssing with 2 MW of electricity and 4 MW of heat, generated from wood chips, since 2003. Güssing ( in Hungarian Németújvár ) is a town in Burgenland, Austria The lords of Güssing (in Hungarian: Köszeg, in Slovak: Kysak) were a noble family in the frontier region of Austria and the Kingdom of Hungary. ...

Gasification processes

Four types of gasifier are currently available for commercial use: counter-current fixed bed, co-current fixed bed, fluidized bed and entrained flow.^[6][7][8] A fluidized bed is formed when a quantity of a solid particulate substance (usually retained in a holding tank) is forced to behave as a fluid; usually by the forced introduction of pressurised gas through the particulate medium. ...

The counter-current fixed bed ("up draft") gasifier consists of a fixed bed of carbonaceous fuel (e.g. coal or biomass) through which the "gasification agent" (steam, oxygen and/or air) flows in counter-current configuration. The ash is either removed dry or as a slag. The slagging gasifiers require a higher ratio of steam and oxygen to carbon in order to reach temperatures higher than the ash fusion temperature. The nature of the gasifier means that the fuel must have high mechanical strength and must be non-caking so that it will form a permeable bed, although recent developments have reduced these restrictions to some extent. The throughput for this type of gasifier is relatively low. Thermal efficiency is high as the gas exit temperatures are relatively low. However, this means that tar and methane production is significant at typical operation temperatures, so product gas must be extensively cleaned before use or recycled to the reactor.

The co-current fixed bed ("down draft") gasifier is similar to the counter-current type, but the gasification agent gas flows in co-current configuration with the fuel (downwards, hence the name "down draft gasifier"). Heat needs to be added to the upper part of the bed, either by combusting small amounts of the fuel or from external heat sources. The produced gas leaves the gasifier at a high temperature, and most of this heat is often transferred to the gasification agent added in the top of the bed, resulting in an energy efficiency on level with the counter-current type. Since all tars must pass through a hot bed of char in this configuration, tar levels are much lower than the counter-current type.

In the fluidized bed gasifier, the fuel is fluidized in oxygen and steam or air. The ash is removed dry or as heavy agglomerates that defluidize. The temperatures are relatively low in dry ash gasifiers, so the fuel must be highly reactive; low-grade coals are particularly suitable. The agglomerating gasifiers have slightly higher temperatures, and are suitable for higher rank coals. Fuel throughput is higher than for the fixed bed, but not as high as for the entrained flow gasifier. The conversion efficiency can be rather low due to elutriation of carbonaceous material. Recycle or subsequent combustion of solids can be used to increase conversion. Fluidized bed gasifiers are most useful for fuels that form highly corrosive ash that would damage the walls of slagging gasifiers. Biomass fuels generally contain high levels of corrosive ash. A fluidized bed is formed when a quantity of a solid particulate substance (usually retained in a holding tank) is forced to behave as a fluid; usually by the forced introduction of pressurised gas through the particulate medium. ... Fluidization (or fluidisation) is a process similar to liquefaction whereby a granular material is converted from a static solid-like state to a dynamic fluid-like state. ...

In the entrained flow gasifier a dry pulverized solid, an atomized liquid fuel or a fuel slurry is gasified with oxygen (much less frequent: air) in co-current flow. The gasification reactions take place in a dense cloud of very fine particles. Most coals are suitable for this type of gasifier because of the high operating temperatures and because the coal particles are well separated from one another. The high temperatures and pressures also mean that a higher throughput can be achieved, however thermal efficiency is somewhat lower as the gas must be cooled before it can be cleaned with existing technology. The high temperatures also mean that tar and methane are not present in the product gas; however the oxygen requirement is higher than for the other types of gasifiers. All entrained flow gasifiers remove the major part of the ash as a slag as the operating temperature is well above the ash fusion temperature. A smaller fraction of the ash is produced either as a very fine dry fly ash or as a black colored fly ash slurry. Some fuels, in particular certain types of biomasses, can form slag that is corrosive for ceramic inner walls that serve to protect the gasifier outer wall. However some entrained bed type of gasifiers do not possess a ceramic inner wall but have an inner water or steam cooled wall covered with partially solidified slag. These types of gasifiers do not suffer from corrosive slags. Some fuels have ashes with very high ash fusion temperatures. In this case mostly limestone is mixed with the fuel prior to gasification. Addition of a little limestone will usually suffice for the lowering the fusion temperatures. The fuel particles must be much smaller than for other types of gasifiers. This means the fuel must be pulverized, which requires somewhat more energy than for the other types of gasifiers. By far the most energy consumption related to entrained bed gasification is not the milling of the fuel but the production of oxygen used for the gasification.

Waste disposal

High Temperature Conversion of Waste (HTCW) reactor. One of many proposed gasification processes which are still to be proven in real life installments.^[9]

Several gasification processes for thermal treatment of waste are under development as an alternative to incineration. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... For other forms of waste plant that produce energy see waste-to-energy. ...

Waste gasification has several principal advantages over incineration:

• The necessary extensive flue gas cleaning may be performed on the syngas instead of the much larger volume of flue gas after combustion
• Electric power may be generated in engines and gas turbines, which are much cheaper and more efficient than the steam cycle used in incineration. Even fuel cells may potentially be used, but these have yet severe requirements to the purity of the gas
• Chemical processing of the syngas may produce other synthetic fuels instead of electricity
• Some gasification processes treat the ash containing e.g. heavy metals at very high temperatures so that the it is released in a glassy and chemically stable form

A major challenge for waste gasification technologies is to reach an acceptable (positive) gross electric efficiency. The high efficiency of converting syngas to electric power is counteracted by significant power consumption in the waste preprocessing, production of large amounts of pure oxygen (which is often used as gasification agent), and gas cleaning. Another challenge becoming apparent when implementing the processes in real life is to obtain high availabilities of the plants, so that for example it is not necessary to close down the plant every few months for cleaning the reactor. For delivered electrical power, see Electrical power industry. ... A colorized automobile engine The internal combustion engine is an engine in which the combustion of fuel and an oxidizer (typically air) occurs in a confined space called a combustion chamber. ... This machine has a single-stage centrifugal compressor and turbine, a recuperator, and foil bearings. ... A steam-electric power plant is a power plant in which the prime mover is steam driven. ... A fuel cell is an electrochemical device similar to a battery, but differing from the latter in that it is designed for continuous replenishment of the reactants consumed; i. ... Synthetic fuel or synfuel is any liquid fuel obtained from coal, natural gas, or biomass. ... In telecommunications and reliability theory, the term availability has the following meanings: 1. ...

Several waste gasification processes have been proposed, but few have yet been built and tested, and only a handful have been implemented as plants processing real waste, and always in combination with fossil fuels^[10].

One plant (in Chiba, Japan using the Thermoselect process^[11]) have been processing industrial waste since year 2000, but has yet not documented positive net energy production from the process. Chiba (千葉市 Chiba-shi) is the capital city of Chiba Prefecture, Japan. ...

See also

Energy Portal

• biofuel
• FutureGen zero-emissions coal-fired power plant
• Fluidized bed
• Fluidized bed combustion
• Isle of Wight gasification facility
• List of solid waste treatment technologies
• Plasma arc waste disposal
• synthetic fuel

Image File history File links Crystal_128_energy. ... For articles on specific fuels used in vehicles, see Biogas, Bioethanol, Biobutanol, Biodiesel, and Straight vegetable oil. ... FutureGen is a project of the US government to build a zero-emissions coal-fired power plant that produces hydrogen and electricity while using carbon dioxide sequestration. ... A fluidized bed is formed when a quantity of a solid particulate substance (usually retained in a holding tank) is forced to behave as a fluid; usually by the forced introduction of pressurised gas through the particulate medium. ... Fluidized bed combustion (FBC) is a combustion technology used in power plants. ... The Isle of Wight gasification facility is a municipal waste treatment plant that has commenced construction in southern England. ... The following page contains a list of different forms of waste treatment Anaerobic digestion ArrowBio Composting Gasification Incineration In-vessel composting Landfill Mechanical biological treatment Mechanical heat treatment Plasma Pyrolysis Recycling Sewage treatment Tunnel composting UASB Windrow composting Categories: | ... Plasma arc gasification is a waste treatment technology that uses high electrical energy and high temperature created by an electrical arc gasifier. ... Synthetic fuel or synfuel is any liquid fuel obtained from coal, natural gas, or biomass. ...

External links

Look up Gasification in
Wiktionary, the free dictionary.

• Pyrolysis and Gasification Factsheet
• Carbon cycle management with increased photo-synthesis and long-term sinks,
• Heat Transfer International Biomass Technology Experts

Wikipedia does not have an article with this exact name. ... Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Web-based project to create a free content dictionary, available in over 151 languages. ...

References

1. ^ Gas Generator Project History of the Gasogene technology.
2. ^ Converting waste to methanol
3. ^ Read, Peter, Carbon cycle management with increased photo-synthesis and long-term sinks. Royal Society of New Zealand, http://www.rsnz.org/topics/energy/ccmgmt.php
4. ^ http://www.renet.at/main_en.php
5. ^ http://www.ficfb.at
6. ^ Beychok, M.R., Process and environmental technology for producing SNG and liquid fuels, U.S. EPA report EPA-660/2-75-011, May 1975
7. ^ Beychok, M.R., Coal gasification for clean energy, Energy Pipelines and Systems, March 1974
8. ^ Beychok, M.R., Coal gasification and the Phenosolvan process, American Chemical Society 168th National Meeting, Atlantic City, September 1974
9. ^ KBI Process Review, www.environment-agency.gov.uk/wtd, Retrieved 28.12.06
10. ^ Gasification case studies by the Environment Agency of England and Wales
11. ^ Thermoselect website - a waste gasification plant supplier