Scientists have found an ingenious way to convert carbon dioxide into jet fuel by using hydrogenation that produces long chain carbon compounds suitable for aviation fuel. If effective then this can be the ultimate sustainable solution we are looking for. So, here’s what the research paper published by nature says about it.
What is it?
The scientists report here a synthetic protocol to the fixation of carbon dioxide by converting it directly into aviation jet fuel using novel, inexpensive iron-based catalysts.
How did they do it?
They prepared the Fe-Mn-K catalyst by the so-called Organic Combustion Method, and the catalyst shows a carbon dioxide conversion through hydrogenation to hydrocarbons in the aviation jet fuel range of 38.2%, with a yield of 17.2%, and a selectivity of 47.8%, and with an attendant low carbon monoxide (5.6%) and methane selectivity (10.4%).
The conversion reaction also produces light olefins ethylene, propylene, and butenes, totalling a yield of 8.7%, which are important raw materials for the petrochemical industry and are presently also only obtained from fossil crude oil.
Converting Carbon Dioxide To Liquid Hydrocarbons
There are two ways to convert CO2 to liquid hydrocarbons;
- an indirect route, which converts CO2 to CO or methanol and subsequently into liquid hydrocarbons,
- or the direct CO2 hydrogenation route, which is usually described as a combination of the reduction of CO2 to CO via the reverse water gas shift (RWGS) reaction and the subsequent hydrogenation of CO to long-chain hydrocarbons via Fischer-Tropsch synthesis (FTS)45.
Jet fuel can then be obtained from the products after industrially recognized treatments such as distillation or hydro-isomerization. The second, direct route is generally recognized as being more economical and environmentally acceptable as it involves fewer chemical process steps, and the overall energy consumption for the entire process is lower46.
How does it make sustainable fuel?
As this carbon dioxide is extracted from air, and re-emitted from jet fuels when combusted in flight, the overall effect is a carbon-neutral fuel.
This contrasts with jet fuels produced from hydrocarbon fossil sources where the combustion process unlocks the fossil carbon and places it into the atmosphere, in longevity, as aerial carbon – carbon dioxide.
How will it help?
With mounting concerns over climate change, the utilisation or conversion of carbon dioxide into sustainable, synthetic hydrocarbons fuels, most notably for transportation purposes, continues to attract worldwide interest. This is particularly true in the search for sustainable or renewable aviation fuels. These offer considerable potential since, instead of consuming fossil crude oil, the fuels are produced from carbon dioxide using sustainable renewable hydrogen and energy.
Renewable jet fuels and the circular economy
The Circular Economy (CE) is an attractive, holistic concept gradually and steadily positioning itself as an alternative and reliable alternative to the present, “Business-as-Usual”, unsustainable Linear Economy (LE) based on the “Take, make and dispose” paradigm.
Nowadays, researchers have risen to the challenge of climate change and advanced the concept of the so-called “CO2 Circular Economy”, which directly integrates CO2 capture from the air (Direct Air Capture, DAC) and converts CO2 into value-added products81,82,83,84. This CO2 Circular Economy is a valid and highly powerful alternative route to simply burying huge volumes of captured CO2 underground and one in which future generations will surely expect us to have formed a major aspect of sustainable CO2 management.
Renewable jet fuels offer considerable potential in the worldwide drive for a future Sustainable Circular Economy Future for the aviation industry. The vision centres on CO2 conversion as an integral part of carbon recycling.
The advances reported in the study offer a route out of the current, worldwide LE for jet fuels, based on the (present) Production-Consumption- Disposal/Emission structure, where the valuable natural resource, crude oil, is extracted, shipped across oceans, transformed into jet fuel and then combusted, with the combustion product either emitted into the atmosphere, or trapped and buried underground (through Carbon Capture and Storage).
On the other hand, the CE approach is based on fundamentally—different Production—Consumption—Recycling/Recovery structure or Carbon Capture and Utilization, where, in this case, CO2 is indeed recognized as a powerful “Resource” to be recirculated using renewable energy to yield carbon-neutral jet aviation fuel.
Obviously, our advance can contribute significantly to more sustainable fuel production process if we input renewable energy into the chain for transforming CO2 into aviation jet fuel as an additional driving force for the inevitable and urgently required transition toward a circular fuel economy centred on renewable CO2 utilization.
Within a Jet Fuel CO2 Circular Economy, the “Goods” (here the Jet Fuel) are continually reprocessed in a closed environment, which saves the natural fossil resources and preserves the environment, whilst also, of course, creating significant numbers of new jobs, new economies and new markets.
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Source: Nature
