Water gas is a kind of

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 ...

, a mixture 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 ...

and

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 ...

. It is produced by "alternately hot blowing a fuel layer okewith air and gasifying it with steam". The caloric yield of the fuel produced by this method is about 10% of the yield from a modern

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 ...

plant. The coke needed to produce water gas also costs significantly more than the precursors for syngas (mainly

methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The abundance of methane on Earth makes ...

from natural gas), making water gas technology an even less attractive business proposition.

Production

Synthesis gas is made by passing

steam Steam is water vapor, often mixed with air or an aerosol of liquid water droplets. This may occur due to evaporation or due to boiling, where heat is applied until water reaches the enthalpy of vaporization. Saturated or superheated steam is inv ...

over a red-hot carbon fuel such as coke: : (Δ''H'' = +131 kJ/mol) The reaction is

endothermic An endothermic process is a chemical or physical process that absorbs heat from its surroundings. In terms of thermodynamics, it is a thermodynamic process with an increase in the enthalpy (or internal energy ) of the system.Oxtoby, D. W; Gillis, ...

, so the fuel must be continually re-heated to maintain the reaction. To do this, an air stream, which alternates with the vapor stream, is introduced to combust some of the carbon: : (Δ''H'' = −393 kJ/mol) Theoretically, to make 6 L of water gas, 5 L of air is required. Alternatively, to prevent contamination with nitrogen, energy can be provided by using pure oxygen to burn carbon into carbon monoxide. : (Δ''H'' = −221 kJ/mol) In this case, 1 L of oxygen will create 5.3 L of pure water gas.

History

The

water-gas shift reaction Water gas is a kind of fuel gas, a mixture of carbon monoxide and hydrogen. It is produced by "alternately hot blowing a fuel layer okewith air and gasifying it with steam". The caloric yield of the fuel produced by this method is about 10% o ...

was discovered by Italian physicist

Felice Fontana Abbé Gasparo Ferdinando Felice Fontana (15 April 1730 – 9 March 1805) was an Italian polymath who contributed to experimental studies in physiology, toxicology, and physics. As a physicist he discovered the water gas shift reaction in 1780. He ...

in 1780. Water gas was made in England from 1828 by blowing steam through white-hot coke.

Hydrocarbonate (gas)

Hydrocarbonate is an archaic term for water gas composed of

and

generated by passing

through glowing coke. Hydrocarbonate was classified as a factitious air and explored for therapeutic properties by some eighteenth-century physicians, including

Thomas Beddoes Thomas Beddoes (13 April 176024 December 1808) was an English physician and scientific writer. He was born in Shifnal, Shropshire and died in Bristol fifteen years after opening his medical practice there. He was a reforming practitioner and te ...

and

James Watt James Watt (; 30 January 1736 (19 January 1736 OS) – 25 August 1819) was a Scottish inventor, mechanical engineer, and chemist who improved on Thomas Newcomen's 1712 Newcomen steam engine with his Watt steam engine in 1776, which was f ...

. The term hydrocarbonate, coined by Beddoes in 1794, should not be confused with the modern name "hydrogen carbonate" for

bicarbonate In inorganic chemistry, bicarbonate (IUPAC-recommended nomenclature: hydrogencarbonate) is an intermediate form in the deprotonation of carbonic acid. It is a polyatomic anion with the chemical formula . Bicarbonate serves a crucial bioche ...

ion. Between 1794 and 1802, physicians such as

Tiberius Cavallo Tiberius Cavallo (also Tiberio) (30 March 1749, Naples, Kingdom of Naples21 December 1809, London, England) was an Italian physicist and natural philosopher. His interests included electricity, the development of scientific instruments, the na ...

and

Davies Gilbert Davies Gilbert (born Davies Giddy, 6 March 1767 – 24 December 1839) was a British engineer, author, and politician. He was elected to the Royal Society on 17 November 1791 and served as its President from 1827 to 1830. He changed his name to ...

experimented with hydrocarbonate as an analgesic and anesthetic.

Humphry Davy Sir Humphry Davy, 1st Baronet (17 December 177829 May 1829) was a British chemist and inventor who invented the Davy lamp and a very early form of arc lamp. He is also remembered for isolating, by using electricity, several Chemical element, e ...

infamously inhaled three quarts of hydrocarbonate at the

Pneumatic Institution The Pneumatic Institution (also referred to as Pneumatic Institute) was a medical research facility in Bristol, England, in 1799–1802. It was established by physician and science writer Thomas Beddoes to study the medical effects of gases, kno ...

and nearly died upon "sinking into annihilation"; Davy recovered two days later and concluded inhalation of more hydrocarbonate could have "destroyed life immediately without producing any painful sensations". He was right:

carbon monoxide poisoning Carbon monoxide poisoning typically occurs from breathing in carbon monoxide (CO) at excessive levels. Symptoms are often described as " flu-like" and commonly include headache, dizziness, weakness, vomiting, chest pain, and confusion. Large ...

can be fatal. Diseases treated by hydrocarbonate included:

tuberculosis Tuberculosis (TB), also known colloquially as the "white death", or historically as consumption, is a contagious disease usually caused by ''Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can al ...

inflammation Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', '' ...

asthma Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wh ...

expectoration Sputum is mucus that is coughed up from the lower airways (the trachea and bronchi). In medicine, sputum samples are usually used for a naked-eye examination, microbiological investigation of respiratory infections, and cytological investigation ...

hemoptysis Hemoptysis or haemoptysis is the discharge of blood or blood-stained sputum, mucus through the mouth coming from the bronchi, larynx, vertebrate trachea, trachea, or lungs. It does not necessarily involve coughing. In other words, it is the airw ...

pneumonia Pneumonia is an Inflammation, inflammatory condition of the lung primarily affecting the small air sacs known as Pulmonary alveolus, alveoli. Symptoms typically include some combination of Cough#Classification, productive or dry cough, ches ...

hydrothorax Hydrothorax is the synonym of pleural effusion in which fluid accumulates in the pleural cavity. This condition is most likely to develop secondary to congestive heart failure, following an increase in hydrostatic pressure within the lungs. More r ...

spasm A spasm is a sudden involuntary contraction of a muscle, a group of muscles, or a hollow organ, such as the bladder. A spasmodic muscle contraction may be caused by many medical conditions, including dystonia. Most commonly, it is a musc ...

and other indications. Many of the diseases treated with hydrocarbonate, whose active ingredient was carbon monoxide, are now being investigated using modern biomedical research methods to determine the therapeutic potential of carbon monoxide. For example,

James Lind James Lind (4 October 1716 – 13 July 1794) was a Scottish physician. He was a pioneer of naval hygiene in the Royal Navy. By conducting one of the first ever clinical trials, he developed the theory that citrus fruits cured scurvy. Lind ...

recognized hydrocarbonate to effectively treat lung inflammation; delivery of carbon monoxide via inhalation protocol or

carbon monoxide-releasing molecules Carbon monoxide-releasing molecules (CORMs) are chemical compounds designed to release controlled amounts of carbon monoxide (CO). CORMs are being developed as potential therapeutic agents to locally deliver CO to cells and tissues, thus overcomin ...

has significant preclinical data indicating an effective treatment for inflammation. The pioneering work of exploratory medicinal application of hydrocarbonate is an important origin for modern drug development.

suggested hydrocarbonate could act as "an antidote to the oxygen in blood" in 1794 and cautioned about the toxicity of an overdose prior to the discoveries of carbon monoxide (1800) and hemoglobin (1840). Despite Watt's observation, it is widely accepted that

Claude Bernard Claude Bernard (; 12 July 1813 – 10 February 1878) was a French physiologist. I. Bernard Cohen of Harvard University called Bernard "one of the greatest of all men of science". He originated the term ''milieu intérieur'' and the associated c ...

had first described the mechanism for carbon monoxide poisoning by describing carbon monoxide's affinity for hemoglobin displacing oxygen to induce asphyxia circa 1857.

Lowe's gas process

In 1873,

Thaddeus S. C. Lowe Thaddeus Sobieski Constantine Lowe (August 20, 1832 – January 16, 1913), also known as Professor T. S. C. Lowe, was an American Civil War aeronaut, scientist and inventor, mostly self-educated in the fields of chemistry, meteorology, and a ...

developed and patented the water gas process by which large amounts of

gas could be generated for residential and commercial use in heating and lighting. This gas provided a more efficient heating fuel than the common

coal gas Coal gas is a flammable gaseous fuel made from coal and supplied to the user via a piped distribution system. It is produced when coal is heated strongly in the absence of air. Town gas is a more general term referring to manufactured gaseous ...

, or coke gas, which was used in municipal service. The process used the water-gas shift reaction: : The process was discovered by passing high-pressure steam over hot

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 ...

, the major source of coke gas. Lowe's process improved upon the chimney systems by which the coal could remain superheated, thereby maintaining a consistently high supply of the gas. The reaction produced carbon dioxide and hydrogen, which, after a process of cooling and " scrubbing", produced hydrogen gas. The process spurred on the industry of gas manufacturing, and

gasification Gasification is a process that converts biomass- or fossil fuel-based carbonaceous materials into gases, including as the largest fractions: nitrogen (N2), carbon monoxide (CO), hydrogen (H2), and carbon dioxide (). This is achieved by reacting ...

plants were established quickly along the eastern seaboard of the United States. Similar processes, like the

Haber–Bosch process The Haber process, also called the Haber–Bosch process, is the main industrial procedure for the production of ammonia. It converts atmospheric nitrogen (N2) to ammonia (NH3) by a reaction with hydrogen (H2) using finely divided iron metal as ...

, led to the manufacture of

ammonia Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...

(NH₃) by the combining 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. ...

, found in

air An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosph ...

, with hydrogen. This spurred on the

refrigeration Refrigeration is any of various types of cooling of a space, substance, or system to lower and/or maintain its temperature below the ambient one (while the removed heat is ejected to a place of higher temperature).IIR International Dictionary of ...

industry, which long used ammonia as its

refrigerant A refrigerant is a working fluid used in the cooling, heating, or reverse cooling/heating cycles of air conditioning systems and heat pumps, where they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are ...

. Lowe also held several patents on artificial ice making machines and was able to run successful businesses in cold storage, as well as products which operated on hydrogen gas.

Variations

Carburetted water gas

Water gas has a lower

heat of combustion The heating value (or energy value or calorific value) of a substance, usually a fuel or food (see food energy), is the amount of heat released during the combustion of a specified amount of it. The ''calorific value'' is the total energy relea ...

than

, so the

calorific value The heating value (or energy value or calorific value) of a substance, usually a fuel or food (see food energy), is the amount of heat released during the combustion of a specified amount of it. The ''calorific value'' is the total energy release ...

was often boosted by passing the gas through a heated

retort In a chemistry laboratory, a retort is a device used for distillation or dry distillation of substances. It consists of a sphere, spherical vessel with a long downward-pointing neck. The liquid to be distilled is placed in the vessel and heat ...

, into which oil was sprayed. The resulting mixed gas was called ''carburetted water gas''. The average composition of carburetted water gas is as follows: 34–38% H; 23–28% CO; 17–21% saturated hydrocarbons; 13–16% unsaturated hydrocarbons; 0.2–2.2% CO; 2.5–5.0% N. It is used as a source of heat, since it has a high calorific value.

Semi-water gas

''Semi-water gas'' is a mixture of water gas and

producer gas Producer gas is a fuel gas manufactured by blowing air and steam simultaneously through a coke or coal fire. It mainly consists of carbon monoxide (CO), hydrogen (H2), as well as substantial amounts of nitrogen (N2). The caloric value of the pro ...

made by passing a mixture of air and steam through heated coke. The heat generated when producer gas is formed keeps the temperature of the coke high enough to allow water gas to be formed.

Water gas shift reaction

Pure hydrogen can be obtained from water gas by using the

Water–gas shift reaction The water–gas shift reaction (WGSR) describes the reaction of carbon monoxide and water vapor to form carbon dioxide and hydrogen: : CO + H2O CO2 + H2 The water gas shift reaction was discovered by Italian physicist Felice Fontana in 1780. It w ...

, after subsequent removal of the carbon dioxide formed when carbon monoxide reacts with water.

Uses

Completely displaced by syngas, water gas could be applied to certain fuel cells. Used in

Fischer–Tropsch process The Fischer–Tropsch process (FT) is a collection of chemical reactions that converts a mixture of carbon monoxide and hydrogen, known as syngas, into liquid hydrocarbons. These reactions occur in the presence of metal catalysts, typically at te ...

. It reacts with producer gas to produce

. It could also be used to gain pure hydrogen for synthesis of ammonia.

References

* Mellor, J.W., ''Intermediate Inorganic Chemistry'', Longmans, Green and Co., 1941, pp. 210–211 * Adlam, G.H.J. and Price, L.S., ''A Higher School Certificate Inorganic Chemistry'', John Murray, 1944, page 309 * History e-book project. ACLS Humanities E-book. Vol 5. "The use of mineral oil" p. 119

Bibliography

Guillaume Delcourt Guillaume Delcourt (31 March 1825 – 2 February 1898) was a Belgian Royal Navy officer, navigator, naval engineer and maritime advisor to Leopold II of Belgium, King Leopold II. He was one of the major players of early Belgian colonial empire, B ...

, ''Notice sur le gaz à l'eau, 1894.'' {{Authority control Fuel gas Hydrogen production Synthetic fuel technologies Industrial gases History of chemistry pl:Gaz wodny