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 a catalyst:
Greenhouse gas emissions from agriculture are large: the agriculture, forestry and land use sectors contribute between 13% and 21% of global greenhouse gas emissions. Direct greenhouse gas emissions include those from rice and livestock farming. Indirect emissions from the conversion of non-agricultural land such as forests into agricultural land are also very important. With regards to direct emissions, nitrous oxide and methane makeup over half of total greenhouse gas emissions from agriculture. A 2023 review emphasizes that emissions from agricultural soils are shaped by factors such as soil type, climate, and management practices. It also highlights several mitigation strategies, including conservation tillage, precision agriculture, improved water use, and the application of biochar, that can reduce emissions and enhance soil carbon storage.
Furthermore, there is also fossil fuel consumption for transport and fertilizer production. For example, the manufacture and use of nitrogen fertilizer contributes around 5% of all global greenhouse gas emissions. Livestock farming is a major source of greenhouse gas emissions.
Fuel efficiency (or fuel economy) is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical potential energy contained in a carrier (fuel) into kinetic energy or work. Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is often illustrated as a continuous energy profile. Non-transportation applications, such as industry, benefit from increased fuel efficiency, especially fossil fuel power plants or industries dealing with combustion, such as ammonia production during the Haber process.
In the context of transport, fuel economy is the energy efficiency of a particular vehicle, given as a ratio of distance traveled per unit of fuel consumed. It is dependent on several factors including engine efficiency, transmission design, and tire design. In most countries, using the metric system, fuel economy is stated as "fuel consumption" in liters per 100 kilometers (L/100 km) or kilometers per liter (km/L or kmpl). In a number of countries still using other systems, fuel economy is expressed in miles per gallon (mpg), for example in the US and usually also in the UK (imperial gallon); there is sometimes confusion as the imperial gallon is 20% larger than the US gallon so that mpg values are not directly comparable. Traditionally, litres per mil were used in Norway and Sweden, but both have aligned to the EU standard of L/100 km.
Abiological nitrogen fixation describes chemical processes that fix (react with) N2, usually with the goal of generating ammonia. The dominant technology for abiological nitrogen fixation is the Haber process, which uses iron-based heterogeneous catalysts and H2 to convert N2 to NH3. This article focuses on homogeneous (soluble) catalysts for the same or similar conversions.
Fritz Jakob Haber (German: [ˈfʁɪt͡s ˈhaːbɐ] ; 9 December 1868 – 29 January 1934) was a German chemist who received the Nobel Prize in Chemistry in 1918 for his invention of the Haber process, a method used in industry to synthesize ammonia from nitrogen gas and hydrogen gas. This invention is important for the large-scale synthesis of fertilizers and explosives. It is estimated that a third of annual global food production uses ammonia from the Haber–Bosch process, and that this food supports nearly half the world's population. For this work, Haber has been called one of the most important scientists and industrial chemists in human history. Haber also, along with Max Born, proposed the Born–Haber cycle as a method for evaluating the lattice energy of an ionic solid.
Haber, a known German nationalist, is also considered the "father of chemical warfare" for his years of pioneering work developing and weaponizing chlorine and other poisonous gases during World War I. He first proposed the use of the heavier-than-air chlorine gas as a weapon to break the trench deadlock during the Second Battle of Ypres. His work was later used, without his direct involvement, to develop the Zyklon B pesticide used for the killing of more than 1 million Jews in gas chambers in the greater context of the Holocaust.
Hydrogen safety covers the safe production, handling and use of hydrogen, particularly hydrogen gas fuel and liquid hydrogen. Hydrogen possesses the NFPA 704's highest rating of four on the flammability scale because it is flammable when mixed even in small amounts with ordinary air. Ignition can occur at a volumetric ratio of hydrogen to air as low as 4% due to the oxygen in the air and the simplicity and chemical properties of the reaction. However, hydrogen has no rating for innate hazard for reactivity or toxicity. The storage and use of hydrogen poses unique challenges due to its ease of leaking as a gaseous fuel, low-energy ignition, wide range of combustible fuel-air mixtures, buoyancy, and its ability to embrittle metals that must be accounted for to ensure safe operation.
Liquid hydrogen poses additional challenges due to its increased density and the extremely low temperatures needed to keep it in liquid form. Moreover, its demand and use in industry—as rocket fuel, alternative energy storage source, coolant for electric generators in power stations, a feedstock in industrial and chemical processes including production of ammonia and methanol, etc.—has continued to increase, which has led to the increased importance of considerations of safety protocols in producing, storing, transferring, and using hydrogen.
![{\displaystyle {\mathrm {N} {\vphantom {A}}_{\smash[{t}]{2}}{}+{}3\,\mathrm {H} {\vphantom {A}}_{\smash[{t}]{2}}{}\mathrel {\longrightleftharpoons } {}2\,\mathrm {NH} {\vphantom {A}}_{\smash[{t}]{3}}}\qquad {\Delta H_{\mathrm {298~K} }^{\circ }=-92.28~{\text{kJ per mole of }}{\mathrm {N} {\vphantom {A}}_{\smash[{t}]{2}}}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/ba3d04f7488f3eb39ea50f0c05bccf43243ae4fe)