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Tower of a Gas Plant in Schlieren, Switzerland

A manufactured gas plant (MGP) was an industrial facility at which gas was produced from coal, oil, and other feedstock. The gas was produced, stored, and then piped to the surrounding area, where it was used for lighting, cooking, and heating homes and businesses. Gas from MGPs was used for all the same purposes that natural gas is used for today. Image File history File links Nuvola_apps_browser. ... Coal (previously referred to as pitcoal or seacoal) is a fossil fuel extracted from the ground by underground mining or open-pit mining (surface mining). ... Natural olive oil Synthetic motor oil Oil, in a general sense, is a chemical compound that is not miscible with water, and is in a liquid state at ambient temperatures. ... Lighting refers to either artificial light sources such as lamps or to natural illumination of interiors from daylight. ... Cooking is an act of preparing food for eating. ... HVAC may also stand for High-voltage alternating current HVAC is an initialism that stands for heating, ventilation and air-conditioning. This is sometimes referred to as climate control. ... Many stoves use natural gas. ...

For a period of over 100 years, manufactured gas plants were an important part of life in cities and towns throughout the United States. They had their beginnings in the early 1800s, providing small amounts of gas for street lighting systems. By 1900, production had greatly increased, and gas was being widely used for heating and cooking. Most towns with populations of more than 5,000 in populace eastern states such as New York had at least one gas plant, and larger towns often had more than one. New York City had several dozen. A streetlight in front of a red sky at night A street light, also known as a light standard, is a raised light on the edge of a road, turned on or lit at a certain time every night. ... Flag Seal Nickname: The Big Apple, The Capital of the World[1], Gotham [2], Metropolis Location Location in the state of New York Government Counties (Boroughs) Bronx (The Bronx) New York (Manhattan) Queens (Queens) Kings (Brooklyn) Richmond (Staten Island) Mayor Michael Bloomberg (R) Geographical characteristics Area     City 1,214. ...

Small-town facilities began to close in the 1920s and 1930s as the industry consolidated production at larger facilities and connected smaller systems together with new pipeline networks. As World War II approached, interstate pipelines were built, making natural gas from the Midwest more widely available, and cheaper than manufactured gas. Combatants Allies: Soviet Union, United Kingdom, France/Free France, United States, Canada, China, India, Australia, Poland, New Zealand, South Africa, and others Axis Powers: Germany, Italy, Japan, Bulgaria, Finland, Romania, Hungary, Burma Casualties Military dead: 17 million Civilian dead: 33 million Total dead: 50 million Military dead: 8 million Civilian... The Midwest is a common name for a region of the United States of America. ...

Gas production

Two main processes were used to produce the gas. The older and simpler process was coal carbonization. In this process, coal was heated in closed retorts or beehive ovens. Inside these ovens, the coal was kept from burning by limiting its contact with outside air. Volatile constituents of the coal would be driven off as a gas, which was collected, cooled, and purified prior to being piped into the surrounding areas for use. The solid portion of the coal would become a black, granular material called coke. Coke was a valuable fuel for many industrial uses and for home heating, because it burned hotter and more cleanly than ordinary coal. Sometimes, the coke was the primary product, and the gas was a by-product, and the facility was called a coke plant. Coal (previously referred to as pitcoal or seacoal) is a fossil fuel extracted from the ground by underground mining or open-pit mining (surface mining). ... For the water carbonator, see Gasogene. ... Coke is a solid carbonaceous residue derived from low-ash, low-sulfur bituminous coal. ...

As the gas manufacturing industry developed and expanded after the Civil War, a new process was introduced which produced a gas mixture that burned hotter and brighter. This process, carburetted water gas (CWG), was first introduced in the 1870s. By 1900, most MGPs in New York State were using this process. However, some MGPs in the state never made the conversion and continued as coal carbonization facilities for their entire lives. 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. ...

A variety of water gas processes were developed, all of which involved a first step in which coke or coal was heated in a closed vessel or retort into which steam was injected. A chemical reaction took place which produced a flammable gas mixture of methane and carbon monoxide. Petroleum products were then sprayed into the hot gas mixture, creating another chemical reaction in which petroleum constituents were "cracked" to form methane, which increased the heating and lighting value of the gas. In physical chemistry, and in engineering, steam refers to vaporized water. ... The simplest hydrocarbon, methane, is a gas with a chemical formula of CH4. ... Carbon monoxide, chemical formula CO, is a colorless, odorless, tasteless, flammable and highly toxic gas. ... In petroleum geology and chemistry, cracking is the process whereby complex organic molecules (e. ...

Environmental legacy

The production of manufactured gas created wastes, some of which may still remain at former MGP sites.

A dense, oily liquid known as coal tar would condense out of the gas at various stages during its production, purification and distribution. Although most of the tar was collected for sale or reuse, recovery was incomplete. Most plants had tar/water separators, which sometimes could not fully separate the two liquids. The resulting tar/water emulsion was often discharged to a nearby surface water body. Over the decades during which many of these MGPs operated, substantial amounts of tar also leaked from storage and processing facilities and contaminated surface soils, subsurface soils, and groundwater. Coal tar is the liquid by-product of the distillation of coal to make coke. ... Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of geologic formations. ...

Today, at a number of former MGP sites, tar or tar/water emulsions continue to migrate slowly in the subsurface and may enter into sewers, basements, or nearby surface water bodies. Under some conditions, tar will temporarily float on the top of surface water bodies, creating oily sheens on the water surface. However, in most cases, the tar will sink to the bottom, leading to contamination of sediments. Whether present due to historic disposal or continuing migration, coal tar may impact water quality and the organisms which live or feed in the sediment. Sediment is any particulate matter that can be transported by fluid flow and which eventually is deposited as a layer of solid particles on the bed or bottom of a body of water or other liquid. ...

Another byproduct, purifier waste, was made up of either lime or wood chips treated with iron oxides, and was used to remove cyanide and sulfur from the manufactured gas. Once it had become saturated with impurities, purifier waste was often discarded or used as a fill material. This waste often contains complexed cyanide compounds which can contaminate groundwater. Purifier waste also generates a strong, objectionable odor when it is exposed on the ground surface. Lime is a general term for various naturally occurring minerals and materials derived from them in which carbonates, oxides and hydroxides of calcium predominate. ... Iron oxide pigment There are a number of iron oxides: Iron oxides Iron(II) oxide or ferrous oxide (FeO) The black-coloured powder in particular can cause explosions as it readily ignites. ... Synthesis of copper(II)-tetraphenylporphine, a metal complex, from tetraphenylporphine and copper(II) acetate monohydrate. ... A space-filling model of the cyanide ion A cyanide is any chemical compound that contains the cyano group -C≡N, with the carbon atom triple-bonded to the nitrogen atom. ...

Current use of MGP sites

Former MGP sites have found a variety of uses in the years since they ceased operations. Many are still owned by the utility companies and are used as electric substations, storage yards, truck garages, office buildings and major generating stations. Many also still contain gas regulating facilities, due to their access to the gas distribution system. Other uses range from abandoned industrial property, to commercial/retail uses, to schools and residences.

Potential problems

These sites often contain abandoned underground structures and pipes containing coal tar or other MGP residuals. Some of these waste materials (especially coal tars) may have migrated from existing/former structures and may be present in the subsurface. Impacts to surface water bodies and their sediments are also common since MGPs were typically located near a source of water.

It is not common to find MGP wastes exposed on the ground surface. Most of these plants have been closed for at least 50 years, and in some cases over 100 years. In many cases, subsequent redevelopment of the MGP sites has removed or covered wastes that were exposed at the surface. However, exposed wastes are sometimes found, and on some sites coal tars may migrate upwards to the ground surface from below.

(Information provided by the New York State Department of Environmental Conservation.)

See also

• Wood gas
• Syngas
• Town gas
• Gasification