Producer gas is a
fuel gas
Fuel gas is one of a number of fuels that under ordinary conditions are gaseous. Most fuel gases are composed of hydrocarbons (such as methane and propane), hydrogen, carbon monoxide, or mixtures thereof. Such gases are sources of energy that c ...
manufactured by blowing air and steam simultaneously through a
coke or
coal
Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.
Coal i ...
fire.
It mainly consists of
carbon monoxide
Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...
(CO),
hydrogen
Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...
(H
2), as well as substantial amounts of
nitrogen
Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...
(N
2). The caloric value of the producer gas is low (mainly because of its high nitrogen content), and the technology is obsolete. Improvements over producer gas, also obsolete, include
water gas, where the solid fuel is treated intermittently with air and steam, and, far more efficiently,
synthesis gas, where the solid fuel is replaced with methane.
In the US, producer gas may also be referred to by other names based on the fuel used for production, such as
wood gas
Wood gas is a fuel gas that can be used for furnaces, stoves, and vehicles. During the production process, biomass or related carbon-containing materials are gasified within the oxygen-limited environment of a wood gas generator to produce a c ...
. Producer gas may also be referred to as suction gas, referring to the way the air was drawn into the
gas generator by an internal combustion engine.
Production
Producer gas is generally made from
coke, or other
carbon
Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ...
aceous material such as
anthracite coal. Air is passed over the red-hot carbonaceous fuel and
carbon monoxide
Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...
is produced. The reaction is
exothermic.
Formation of producer gas from air and carbon:
:C + O → CO, +97,600 calories/mol
:CO + C → 2CO, –38,800 calories/mol (mol of the reaction formula)
:2C + O → 2CO, +58,800 calories/mol (per mol of O i.e. per mol of the reaction formula)
Reactions between steam and carbon:
:HO + C → H + CO, –28,800 calories/mol (presumably mol of the reaction formula)
:2HO + C → 2H + CO, –18,800 calories/mol (presumably mol of the reaction formula)
Reaction between steam and carbon monoxide:
:HO + CO → CO + H, +10,000 calories/mol (presumably mol of the reaction formula)
:CO + H → CO + HO, –10,000 calories/mol (presumably mol of the reaction formula)
The average composition of ordinary producer gas according to Latta was: CO: 5.8%; O: 1.3%; CO: 19.8%; H: 15.1%; CH: 1.3%; N: 56.7%; B.T.U. gross per cu.ft 136 The concentration of carbon monoxide in the "ideal" producer gas was considered to be 34.7% carbon monoxide (carbonic oxide) and 65.3% nitrogen.
After "scrubbing", to remove
tar, the gas may be used to power
gas turbine
A gas turbine or gas turbine engine is a type of Internal combustion engine#Continuous combustion, continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas gene ...
s (which are well-suited to fuels of low
calorific value), spark ignited engines (where 100% petrol fuel replacement is possible) or diesel internal combustion engines (where 15% to 40% of the original diesel fuel requirement is still used to ignite the gas ).
During
World War II
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
in Britain, plants were built in the form of trailers for towing behind commercial vehicles, especially buses, to supply gas as a replacement for petrol (gasoline) fuel. A range of about 80 miles for every charge of anthracite was achieved.
In old movies and stories, when there is a description of suicide by "turning on the gas" and leaving an oven door open without lighting the flame, the reference was to coal gas or town gas. As this gas contained a significant amount of carbon monoxide it was quite toxic. Most town gas was also odorized, if it did not have its own odor. Modern 'natural gas' used in homes is far less toxic, and has a
mercaptan
In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl grou ...
added to it for odor for identifying leaks.
Alternative names
Various names are used for producer gas, air gas and water gas generally depending on the fuel source, process or end use including:
* Air gas: also called "power gas", "generator gas", or "Siemens' producer gas". Produced from various fuels by partial combustion with air. Air gas consists principally of carbon monoxide with nitrogen from the air used and a small amount of hydrogen. This term is not commonly used, and tends to be used synonymously with wood gas.
* Producer gas: Air gas modified by simultaneous injection of water or steam to maintain a constant temperature and obtain a higher heat content gas by enrichment of air gas with H. Current usage often includes air gas.
* Semi-water gas: Producer gas.
* Blue water-gas: Air, water or producer gas produced from clean fuels such as coke, charcoal and anthracite which contain insufficient hydrocarbon impurities for use as illuminating gas. Blue gas burns with a blue flame and does not produce light except when used with a Welsbach
gas mantle.
* Lowe's Water Gas: Water gas with a secondary pyrolysis reactor to introduce hydrocarbon gasses for illuminating purposes.
* Carburetted gas: Any gas produced by a process similar to Lowe's in which hydrocarbons are added for illumination purposes.
* Wood gas: produced from wood by partial combustion. Sometimes used in a gasifier to power cars with ordinary internal combustion engines.
Other similar fuel gasses
* Coal gas or illuminating gas: Produced from coal by distillation.
* Water gas: Produced by injection of steam into fuel preheated by combustion with air. The reaction is endothermic so the fuel must be continually re-heated to keep the reaction going. This was usually done by alternating the steam with an air stream. This name is sometimes used incorrectly when describing carburetted blue water gas simply as blue water gas.
* Coke oven gas: Coke ovens give off a gas exactly similar to illuminating gas, part of which is used to heat the coal. There may be a large excess, however, which is used for industrial purposes after it has been purified.
*
Syngas
Syngas, or synthesis gas, is a mixture of hydrogen and carbon monoxide in various ratios. The gas often contains some carbon dioxide and methane. It is principally used for producing ammonia or methanol. Syngas is combustible and can be used as ...
, or synthesis gas: (from synthetic gas or synthesis gas) can be applied to any of the above gasses, but generally refers to modern industrial processes, such as natural gas reforming,
hydrogen production
Hydrogen gas is produced by several industrial methods. Nearly all of the world's current supply of hydrogen is created from fossil fuels. Article in press. Most hydrogen is ''gray hydrogen'' made through steam methane reforming. In this process, ...
, and processes for synthetic production of methane and other hydrocarbons.
* City (Town) gas: any of the above-manufactured gases including producer gas containing sufficient hydrocarbons to produce a bright flame for illumination purposes, originally produced from coal, for sale to consumers and municipalities.
Advantages
* There is no loss due to smoke and convection current.
* Quantity of air required for the combustion of producer gas is not much above the theoretical quantity; when burning solid fuel, far more than the theoretical quantity is required. With solid fuels, the larger quantity of exhaust takes away considerable heat with it.
* Producer gas is more easily transmitted than solid fuel.
* Gas-fired furnaces can be maintained at a constant temperature.
* With gas, an oxidising and reducing flame can be obtained.
* Heat loss due to converting solid fuel into producer gas can be made in an economic way.
* Smoke nuisance can be avoided.
* Producer gas can be produced even by the poorest quality of fuel.
* When used in a large furnace no scrubbing is required.
Scrubbing is necessary in a small furnace to avoid choking small burners, and for using internal combustion engines.
See also
*
Fuel gas
Fuel gas is one of a number of fuels that under ordinary conditions are gaseous. Most fuel gases are composed of hydrocarbons (such as methane and propane), hydrogen, carbon monoxide, or mixtures thereof. Such gases are sources of energy that c ...
*
Gasification
*
Gasifier
*
History of manufactured gas
*
Pyrolysis
Pyrolysis is a process involving the Bond cleavage, separation of covalent bonds in organic matter by thermal decomposition within an Chemically inert, inert environment without oxygen. Etymology
The word ''pyrolysis'' is coined from the Gree ...
*
Water gas
*
Wood gas
Wood gas is a fuel gas that can be used for furnaces, stoves, and vehicles. During the production process, biomass or related carbon-containing materials are gasified within the oxygen-limited environment of a wood gas generator to produce a c ...
References
* Mellor, J.W., ''Intermediate Inorganic Chemistry'', Longmans, Green and Co., 1941, page 211
* Adlam, G.H.J. and Price, L.S., ''A Higher School Certificate Inorganic Chemistry'', John Murray, 1944, page 309
External links
Paxman Suction Gas Producers
{{DEFAULTSORT:Producer Gas
Fuel gas
Industrial gases