Ammonia suggested as a possible future “low carbon” jet fuel…

ammonia-suggested-as-a-possible-future-“low-carbon”-jet-fuel…

Ammonia suggested as a possible future “low carbon” jet fuel…

Ammonia suggested as a possible future “low carbon” jet fuel – but problematic
2021-11-14 11:00:00
A British company is hoping to use ammonia, in order to create “low carbon” flight in future decades.  The hope is to produce ammonia (NH3) using the very energy intensive Haber Bosch process, which is how fertiliser is produced.  Unless it used genuinely low carbon electricity for the process, a lot of carbon would be produced. The aspiration is that liquid ammonia could be stored in tanks on aircraft, and then – using the heat from the engines – “cracked” to produce hydrogen, which would fuel the plane. However NOx gases is produced in the process, and N2O is a highly potent greenhouse gas. Engines would need to have a second process, to turn the NOx into just water and nitrogen gas. The company wanting to do this hopes existing planes could be modified, though this would mean installing the cracker/heat exchanger unit next to each engine pod on an aircraft wing, and changes to fuel tanks. It is likely that an airliner with these modifications would only be able to fly short trips, of under 2,000km.  Ammonia fuel would cost a great deal more than fossil kerosene – and it is a toxic and corrosive substance, that can damage many metals.   .Tweet British firm to unveil technology for zero-carbon emission flights at Cop26 As yet unnamed company claims it could enable ‘clean’ flights running on liquid ammonia by 2030 By Gwyn Topham Transport correspondent (Guardian) @GwynTopham Fri 5 Nov 2021 A British company being launched at the Cop26 summit on Friday will unveil technology it claims could enable zero-carbon emission flights running on liquid ammonia by 2030. It aims to build lightweight reactors to “crack” the chemical to produce hydrogen to burn as fuel, a design it says could allow existing planes to be modified to store liquid ammonia rather than kerosene. Hydrogen is currently seen as the only possible “clean” fuel for future long-haul aviation, but the difficulty of safely storing it in fuel tanks, either as a gas or highly cooled liquid, means aerospace manufacturers have argued that vastly different planes would be needed. Small reactors could be retrofitted into passenger planes to allow the hydrogen to be obtained from ammonia, according to scientists on the UK’s state-funded Science and Technology Facilities Council, who have demonstrated that a mix of cracked ammonia can burn with similar properties as the kerosene normally used as jet fuel. The new joint venture, as yet unnamed, will combine their findings with rocket engine technology from Reaction Engines, with seed funding from cleantech investor IP Group. They believe the first sector likely to adopt their technology is shipping. Ammonia has already been seen as a cleaner fuel for the maritime sector, and could be a readily available fuel, as a product that is currently widely transported and stored globally. However, most of the world’s ammonia is produced from fossil fuels in an energy-intensive process [the Haber Bosch process – very energy intensive – used to make fertiliser] that is responsible for 1-2% of global carbon emissions. To be truly carbon-neutral, the new aircraft would have to run on “green ammonia”, produced from water and air using renewable energy. Cracking the ammonia using the reactors on the plane produces hydrogen and nitrogen, and the emissions are water and nitrous oxides (NOx). NOx is an indirect greenhouse gas and can lead to the formation of health-damaging air pollutants such as particulate matter. The cost of ammonia, or hydrogen, would far outstrip kerosene as a jet fuel, but the firms hope carbon taxes and legislation will alter the future economics. Aviation and shipping currently account for 5% of worldwide CO2 emissions and their impact is expected to grow without significant technological or behavioural change. The British government last year set up a jet zero council with the aim of decarbonising flight, with Boris Johnson suggesting that the UK could build an actual zero-emission transatlantic plane by 2050. [Which is, of course utter irresponsible Boris bollocks. AW comment].  The industry has signed up to a net zero pledge for 2050, which relies heavily on offsetting and sustainable fuels. Cracking ammonia onboard, if proved feasible, could give zero-carbon flight 20 years earlier, the new joint venture suggests, although large challenges would remain to decarbonise production of ammonia, reduce NOx, and tackle the effects of aircraft contrails that contribute to global warming. [The non-CO2 impacts probably at least double

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