Hydrogen is used in the production of carbon steels, special metals and semiconductors. In the electronics industry, it is widely employed as a reducing agent and as a carrier gas. High-purity hydrogen is also used as a carrier gas in gas chromatography.
Nowadays, hydrogen is used in several industrial processes. Among other applications, it is important to point its use as raw material in the chemical industry, and also as a reductor agent in the metallurgic industry. Hydrogen is a fundamental building block for the manufacture of ammonia, and hence fertilizers, and of methanol, used in the manufacture of many polymers. Refineries, where hydrogen is used for the processing of intermediate oil products, are another area of use. Thus, about 55 % of the hydrogen produced around the world is used for ammonia synthesis, 25 % in refineries and about 10 % for methanol production. The other applications worldwide account for only about 10 % of global hydrogen production.
Ammonia - Fertilizers
The most important hydrogen-nitrogen compound is ammonia (NH3), also known as azane. Technically, ammonia is obtained on a large scale by the Haber-Bosch process. This process combines hydrogen and nitrogen together directly by synthesis. To this end, the starting materials nitrogen and hydrogen must first be obtained. In the case of nitrogen this is achieved by low-temperature separation of air, while hydrogen originates today from natural gas steam reforming.
Almost 90 % of ammonia goes into fertilizer production. For this purpose, a large part of the ammonia is converted into solid fertilizer salts or, after catalytic oxidation, into nitric acid (HNO3) and its salts (nitrates). Owing to its high energy of evaporation, ammonia is also used in refrigeration plants as an environmentally friendly and inexpensively produced refrigerant; its technical name is R-717.
Hydrogen is used in various in industrial applications; these include metalworking (primarily in metal alloying), flat glass production (hydrogen used as an inerting or protective gas), the electronics industry (used as a protective and carrier gas, in deposition processes, for cleaning, in etching, in reduction processes, etc.), and applications in electricity generation, for example for generator cooling or for corrosion prevention in power plant pipelines.
The direct reduction of iron ore – i.e. the separation of oxygen from the iron ore using hydrogen and synthesis gas – could develop into an important industrial process in steel manufacturing, because in the traditional blast furnace method large amounts of carbon are released. While direct reduction with natural gas is now well-established in steel production (World Steel Association 2015), corresponding production methods based on hydrogen so far exist only on a pilot scale.
Hydrogen is used to process crude oil into refined fuels, such as gasoline and diesel, and also for removing contaminants, such as sulphur, from these fuels.
Hydrogen use in refineries has increased in recent years for different reasons:
(i) the strict regulations that require low sulphur in diesel,
(ii) the increased consumption of low quality ‘heavy’ crude oil, which requires more hydrogen to refine and
(iii) the increased oil consumption in developing economies such as China and India.
Approximately 75% of the hydrogen currently consumed worldwide by oil refineries is supplied by large hydrogen plants that generate hydrogen from natural gas or other hydrocarbon fuels
Hydrogen is also an important basic substance for producing methanol (CH 3 OH). The production of methanol (methanol synthesis) takes place by means of the catalytic hydrogenation of carbon monoxide.
Methanol can be used directly as a fuel in internal combustion engines. It is also used in direct methanol fuel cells or, after reforming, in PEM fuel cells. Fuel additives are produced from methanol, and it is used to transesterify vegetable oils to form methyl esters (biodiesel).