The Fischer-Tropsch process

Emily Horn and the sunset

Those hoping to understand energy politics in the coming decades would be well advised to read up on the Fischer-Tropsch process. This chemical process uses catalysts to convert carbon monoxide and hydrogen into liquid hydrocarbons. Basically, it allows you to make gasoline using any of a large number of inputs as a feedstock. If the input you use is coal, this process is environmentally disastrous. It combines all the carbon emissions associated with coal burnings with extra energy use for synthetic fuel manufacture, not to mention the ecological and human health effects of coal mining. If the feedstock is biomass, it is possible that it could be a relatively benign way to produce liquid fuels for transport.

The process was developed in Germany during the interwar period and used to produce synthetic fuels during WWII. The fact that it can reduce military dependence on imported fuel is appealing to any state that wants to retain or enhance its military capacity, but feels threatened by the need to import hydrocarbons. The US Air Force has shown considerable interest for precisely that reason, though they are hoping to convert domestic coal or natural gas into jet fuel – an approach that has no environmental benefits. By contrast, biomass-to-liquids offers the possibility of carbon neutral fuels. All the carbon emitted by the fuel was absorbed quite recently by the plants from which it was made.

Such fuels are extremely unlikely to ever be as cheap as gasoline and kerosene – even with today’s oil prices. The fact that there are parts of the world where you can just make a hole in the ground and watch oil spray out ensures that. That said, Fisher-Tropsch-generated fuels could play an important part in a low-carbon future, provided three conditions are met: (a) the fuels are produced from biomass, not coal or natural gas (b) the energy used in the production process comes from sustainable low-carbon sources and (c) the process of growing the biomass is not unacceptably harmful in other ways. If land is redirected towards growing biomass in a way that encourages deforestation or starves the poor, we will not be able to legitimately claim that synthetic fuels are a solution.

Author: Milan

In the spring of 2005, I graduated from the University of British Columbia with a degree in International Relations and a general focus in the area of environmental politics. In the fall of 2005, I began reading for an M.Phil in IR at Wadham College, Oxford. Outside school, I am very interested in photography, writing, and the outdoors. I am writing this blog to keep in touch with friends and family around the world, provide a more personal view of graduate student life in Oxford, and pass on some lessons I've learned here.

8 thoughts on “The Fischer-Tropsch process”

  1. Synfuels turns “stranded” natural gas into gasoline

    By Tyler on Main Page

    A Texas company, Synfuels International, has come up with a way to turn natural gas into gasoline and other liquid fuels that is much cheaper and cleaner than established processes, namely the Fischer-Tropsch approached used since Nazi Germany converted coal and coal-bed methane into diesel fuel back during the Second World War.

    Now why would anyone convert natural gas into gasoline? It’s not that all natural gas would undergo this process. The target is natural gas that results as a byproduct of oil extraction in remote locations. Oil companies, more focused on getting at the oil, usually flare or vent natural gas that comes to the surface because it’s too expensive to build a dedicated pipeline that would collect it and send it to market. A lot of this gas is wasted this way. The World Bank estimates about 150 billion cubic meters every year is flared — the combined total gas consumption of France and Germany. The associated greenhouse gas emissions are enormous.

    Some, such as BP and Shell, have counted on Fischer-Tropsch plants as a less expensive alternative to building a dedicated natural gas pipeline. The plants would convert the natural gas into gasoline, diesel or jet fuel and transport it by truck/ship, or send it to market inside existing oil pipelines. Unfortunately the cost of Fischer-Tropsch still remains too high. Synfuels hope to change the game, offering plants that have a third the footprint of a Fischer-Tropsch plant but with the same output. “Why use a sledgehammer when you only need a hammer?” said Synfuels president Tom Rolfe. Scientists behind the company figure they can produce, on small scale, a barrel of gasoline from natural gas for about $25, compared to $35 for a Fischer-Tropsch plant benefiting from economies of scale. They also say their plant is cleaner, producing none of the hard waxes, toxic byproducts and other “crud” associated with Fischer-Tropsch.

    For a full story on the Synfuels technology check out this article in MIT Technology Review. I don’t typically write about better ways to use fossil fuels, but in this case if we can put more natural gas to use rather than flare/vent it, and at the same time displace the use of oil, then it’s something that should be pursued.

  2. Biomass-to-Liquids

    When an organic material is burned (e.g., natural gas, coal, biomass), it can be completely oxidized (gasified) to carbon dioxide and water, or it can be partially oxidized to carbon monoxide and hydrogen. The latter partial oxidation (POX), or gasification reaction, is accomplished by restricting the amount of oxygen during the combustion. The resulting mixture of carbon monoxide and hydrogen is called synthesis gas (syngas) and can be used as the starting material for a wide variety of organic compounds, including transportation fuels.

    Syngas may be used to produce long-chain hydrocarbons via the Fischer-Tropsch (FT) reaction.

  3. “Like GTL and CTL, development of BTL is presently hampered by high capital costs. According to the Energy Information Administration’s Annual Energy Outlook 2006, capital costs per daily barrel of production are $15,000-20,000 for a petroleum refinery, $20,000-$30,000 for an ethanol plant, $30,000 for GTL, $60,000 for CTL, and $120,000-$140,000 for BTL (EIA 2006). “

  4. Gasification: Biomass to Liquids

    The following example is just one reason I think gasification is going to play a big part in our future. During World War II, the Germans were cut off from liquid fuel supplies. In order to keep the war machine running, they turned to coal to liquids, or CTL (coal gasification followed by Fischer-Tropsch to liquids) for their liquid fuel needs. At peak production, the Germans were producing over five million gallons of synthetic fuel a day. To put matters into perspective, five million gallons probably exceeds the historical sum of all the cellulosic ethanol or synthetic algal biofuel ever produced. Without a doubt, one week’s production from Germany’s WWII CTL plants dwarfs the combined historical output of two technologies upon which the U.S. government and many venture capitalists are placing very large bets.

    South Africa during Apartheid had a similar experience. With sanctions restricting their petroleum supplies, they turned to their large coal reserves and once again used CTL. Sasol (South African Coal, Oil and Gas Corporation) – out of necessity – has been a pioneer in gasification technology. Today, they have a number of gasification facilities, including the 160,000 bbl/day Secunda CTL facility, which has been highly profitable for the company (but very expensive relative to oil prices when constructed). In total, Sasol today synthetically produces about 40% of South Africa’s liquid fuel.

    While we can speculate on the source of future fuel supplies in a petroleum constrained world, we do know that two countries that already found themselves in that position turned to gasification as a solution. The technology has a track record and is scalable. The same can’t be said for many of the technologies upon which we are pinning our hopes (and taxpayer dollars). We hope these other technologies scale and that technical breakthroughs allow them to compete. But gasification has already proven itself as a viable go-to option. There are presently a number of operating CTL and GTL plants around the world. Shell has been running their Bintulu GTL plant for 15 years, and is currently building the world’s largest GTL plant with a capacity of 140,000 barrels/day.

    The biomass to liquid fuel efficiency for gasification is around 70% (See Section 1.2.2: Second-Generation Biofuels), a number cellulosic ethanol will never approach. In short, no other technology to my knowledge can convert a higher percentage of the embedded energy in biomass into liquid fuels.

    Of course there’s always a catch. Despite large reserves of coal, the United States has not turned to gasification as a solution. Why? High capital costs. At the end of the day the desire to keep fuel prices low consistently overrides our desire for energy security. (There is also environmental pressure over using coal gasification which should not be an issue for waste biomass gasification).

    But biomass is more difficult to handle, so there are added costs above those of coal gasification. So you are talking about a process that is more capital intensive than a conventional oil refinery, or even a cellulosic ethanol plant. But what you save on the cellulosic ethanol plant ultimately costs a lot in overall energy efficiency. Until someone actually scales up and runs a cellulosic ethanol plant, we can only speculate as to whether the process is truly a net energy producer at scale.

    Interestingly, one of the “cellulosic ethanol” hopefuls that we often hear so much about – Range Fuels – is actually a gasification plant. (Ditto Coskata). The front end of their process is intended to produce syngas in a process very similar to that of World War II Germany. For their back end they intend to produce ethanol, which in my opinion is an odd choice that was driven purely by ethanol subsidies. But this is definitely not the optimal end product of a gasification process. They are going to lose a lot of efficiency to byproducts like methanol (which is actually a good end product for a gasification plant) – and that’s assuming they get their gasification process right. They are then going to expend some of their net energy trying to purify the ethanol from the mixed alcohols their process will produce.

    The question for me is not whether BTL can displace 20% of our petroleum usage. It absolutely can. The question is whether we are prepared to accept domestic fuel that will cost more to produce. In the long run – if oil prices continue to rise – then BTL plants that are built today will become profitable. The risk is that a sustained period of oil prices in the $50-$70 range will retard BTL development. But I don’t expect that to happen.

  5. To turn it into aviation fuel, he suggests siting the electrolysers near plants extracting CO2 from the air—a process known as Direct Air Capture (dac). The gas would be converted into carbon monoxide and combined with hydrogen using the 100-year-old Fischer-Tropsch process that is used to make liquid fuels, all powered by renewable energy. The fuel could be refined into kerosene and other products, such as diesel for marine transportation and naphtha for use in the chemicals industry. When burned, there would be no net addition of carbon dioxide to the atmosphere. “It would work like nature,” says Dr Breyer.

    Unfortunately dac is the most nascent of nascent technologies. Yet it is attracting the attention of influential promoters such as Bill Gates, founder of Microsoft. Initially it was conceived as a way to reduce the amount of CO2 in the atmosphere; if a captured CO2 molecule can be burned again to keep people flying, at least it does not add to the overall stock.

    The firm backed by Mr Gates is Carbon Engineering, based in Canada, that has run a dac pilot project since 2015 that is capable of extracting one tonne of CO2 per day, and has produced synthetic fuels since 2017. Another firm is Climeworks of Switzerland. Estimates have suggested the dac technology can cost up to $600 per ton of CO2 removed, but in a recent paper in Joule, an energy journal, Geoffrey Holmes of Carbon Engineering and others argue that costs can be below $100 per ton if done at scale.

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