Stretford process
Encyclopedia
The Stretford process was developed during the late 1940s to remove hydrogen sulfide
(H2S) from town gas. It was the first liquid phase, oxidation process for converting H2S into sulfur to gain widespread commercial acceptance. Developed by Tom Nicklin of the North-Western Gas Board (NWGB) and the Clayton Aniline Company
, in Manchester
, England, the name of the process was derived from the location of the NWGB's laboratories, in Stretford
.
The process uses reduction-oxidation (redox
) chemistry to oxidise the H2S into elemental sulfur, in an alkaline solution containing vanadium
as an oxygen carrier.
The process was licensed by NWGB, which later became part of British Gas
. At the height of its popularity during the 1970s there were more a dozen companies offering the Stretford technology. By 1987 about 170 Stretford plants had been built worldwide, and more than 100 were still operating in 1992, capable of removing 400,000 tons of sulfur per year. The first USA plant was commissioned in 1971 at Long Beach, California
, to process the gas from offshore oil wells.
Hydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...
(H2S) from town gas. It was the first liquid phase, oxidation process for converting H2S into sulfur to gain widespread commercial acceptance. Developed by Tom Nicklin of the North-Western Gas Board (NWGB) and the Clayton Aniline Company
Clayton Aniline Company
The Clayton Aniline Company Ltd. was a British manufacturer of dyestuffs, founded in 1876 by Charles Dreyfus in Clayton, Manchester.-Early history:...
, in Manchester
Greater Manchester
Greater Manchester is a metropolitan county in North West England, with a population of 2.6 million. It encompasses one of the largest metropolitan areas in the United Kingdom and comprises ten metropolitan boroughs: Bolton, Bury, Oldham, Rochdale, Stockport, Tameside, Trafford, Wigan, and the...
, England, the name of the process was derived from the location of the NWGB's laboratories, in Stretford
Stretford
Stretford is a town within the Metropolitan Borough of Trafford, in Greater Manchester, England. Lying on flat ground between the River Mersey and the Manchester Ship Canal, it is to the southwest of Manchester city centre, south-southwest of Salford and northeast of Altrincham...
.
The process uses reduction-oxidation (redox
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....
) chemistry to oxidise the H2S into elemental sulfur, in an alkaline solution containing vanadium
Vanadium
Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery gray, ductile and malleable transition metal. The formation of an oxide layer stabilizes the metal against oxidation. The element is found only in chemically combined form in nature...
as an oxygen carrier.
The process was licensed by NWGB, which later became part of British Gas
British Gas plc
British Gas plc was formerly the monopoly gas supplier and is a private sector in the United Kingdom.- History :In the early 1900s the gas market in the United Kingdom was mainly run by county councils and small private firms...
. At the height of its popularity during the 1970s there were more a dozen companies offering the Stretford technology. By 1987 about 170 Stretford plants had been built worldwide, and more than 100 were still operating in 1992, capable of removing 400,000 tons of sulfur per year. The first USA plant was commissioned in 1971 at Long Beach, California
Long Beach, California
Long Beach is a city situated in Los Angeles County in Southern California, on the Pacific coast of the United States. The city is the 36th-largest city in the nation and the seventh-largest in California. As of 2010, its population was 462,257...
, to process the gas from offshore oil wells.