This article may be expanded with text translated from the corresponding article in French. (January 2014) Click [show] for important translation instructions. View a machine-translated version of the French article. Machine translation like DeepL or Google Translate is a useful starting point for translations, but translators must revise errors as necessary and confirm that the translation is accurate, rather than simply copy-pasting machine-translated text into the English Wikipedia. Consider adding a topic to this template: there are already 4,879 articles in the main category, and specifying|topic= will aid in categorization. Do not translate text that appears unreliable or low-quality. If possible, verify the text with references provided in the foreign-language article. You must provide copyright attribution in the edit summary accompanying your translation by providing an interlanguage link to the source of your translation. A model attribution edit summary is Content in this edit is translated from the existing French Wikipedia article at [[:fr:Gaz de haut fourneau]]; see its history for attribution. You should also add the template ((Translated|fr|Gaz de haut fourneau)) to the talk page. For more guidance, see Wikipedia:Translation.
An early internal combustion blowing engine of around 1900, powered by furnace gas
An early internal combustion blowing engine of around 1900, powered by furnace gas

Blast furnace gas (BFG)[1] is a by-product of blast furnaces that is generated when the iron ore is reduced with coke to metallic iron. It has a very low heating value, about 93 BTU/cubic foot (3.5 MJ/m3),[2] because it consists of about 51 vol% nitrogen and 22 vol% carbon dioxide, which are not flammable. The rest amounts to around 22 vol% carbon monoxide, which has a fairly low heating value already and 5 vol% hydrogen.[3] Per ton of steel produced via the blast furnace route, 2.5 to 3.5 ton of blast furnace gas is produced. It is commonly used as a fuel within the steel works, but it can be used in boilers and power plants equipped to burn it. It may be combined with natural gas or coke oven gas before combustion or a flame support with richer gas or oil is provided to sustain combustion. Particulate matter is removed so that it can be burned more cleanly. Blast furnace gas is sometimes flared without generating heat or electricity.

Blast furnace gas is generated at higher pressure and at about 100–150 °C (212–302 °F) in a modern blast furnace. This pressure is utilized to operate a generator (Top-gas-pressure Recovery Turbine - i.e. TRT in short), which can generate electrical energy up to 35 kWh/t of pig iron without burning any fuel. Dry type TRTs can generate more power than wet type TRT.

Auto ignition point of blast furnace gas is approximate 630–650 °C (1,166–1,202 °F) and it has LEL (Lower Explosive Limit) of 27% & UEL (Upper Explosive Limit) of 75% in an air-gas mixture at normal temperature and pressure.

The high concentration of carbon monoxide makes the gas hazardous.

See also

Sources

  1. ^ Blast Furnace Gas-Fired Boiler for Eregli Iron & Steel Works (Erdemir), Turkey Archived September 30, 2011, at the Wayback Machine
  2. ^ "93 BTU%2Fcbft in MJ%2Fm%5E3 - Wolfram|Alpha".
  3. ^ De Ras, Kevin; Van De Vijver, Ruben; Galvita, Vladimir V.; Marin, Guy B.; Van Geem, Kevin M. (2019-12-01). "Carbon capture and utilization in the steel industry: challenges and opportunities for chemical engineering". Current Opinion in Chemical Engineering. 26: 81–87. doi:10.1016/j.coche.2019.09.001. ISSN 2211-3398. S2CID 210619173.