World energy consumption projections expect coal to stay one of the world’s main energy sources in the coming decades, and a growing share of it will be used in CTL, the conversion of coal to liquid fuels. Researchers from the National Institute of Clean-and-Low-Carbon Energy in Beijing and Eindhoven University of Technology have developed iron-based catalysts that substantially reduce operating costs and open the door to capturing the large amounts of CO2that are generated by CTL. Their results are published in the journal Science Advances.
To understand the significance of this achievement, some knowledge of the CTL process is required. The first stage is the conversion of coal to syngas, a mixture of carbon monoxide (CO) and hydrogen (H2). Using the so-called Fischer-Tropsch process, these components are converted to liquid fuels. But before that can be done, the composition of the syngas has to be changed to make sure the right products come out in the end – liquid fuels. So some of the CO is taken out of the syngas (rejected) by converting it to CO2, in a process called ‘water-gas shift’.
In this chain the researchers tackled a key problem in the Fischer-Tropsch reactor. As in most chemical processing, catalysts are required to enable the reactions. CTL catalysts are mainly iron based. Unfortunately, they convert some 30 percent of the CO to unwanted CO2, a byproduct that in this stage is hard to capture and thereby often released in large volumes, consuming a lot of energy without benefit.
The Beijing and Eindhoven researchers discovered that the CO2 release is caused by the fact that the iron based catalysts are not pure, but consist of several components. They were able to produce a pure form of a specific iron carbide, called epsilon iron carbide, that has a very low CO2 selectivity. In other words, it generates almost no CO2 at all. The existence was already known but until now it had not been stable enough for the harsh Fischer-Tropsch process. The Sino-Dutch research team has now shown that this instability is caused by impurities in the catalyst. The phase-pure epsilon iron carbide they developed is, by contrast, stable and remains functional, even under typical industrial processing conditions of 23 bar and 2500C.
The new catalyst eliminates nearly all CO2 generation in the Fischer-Tropsch reactor. This can reduce the energy needed and the operating costs by roughly 25 million euros per year for a typical CTL plant. The CO2 that was previously released in this stage can now be removed in the preceding water-gas shift stage. That is good news, because it is much easier to capture in this stage. The technology to make this happen is called CCUS (carbon capture, utilization and storage). It has been developed by other parties and is already being applied in several pilot plants.
The conversion of coal to liquid fuels is especially relevant in coal-rich countries that have to import oil for their supply of liquid fuels, such as China and the US. “We are aware that our new technology facilitates the use of coal-derived fossil fuels. However, it is very likely that coal-rich countries will keep on exploiting their coal reserves in the decades ahead. We want to help them do this in the most sustainable way,” says lead researcher professor Emiel Hensen of Eindhoven University of Technology.
The research results are likely to reduce the efforts to develop CTL catalysts based on cobalt. Cobalt based catalysts do not have the CO2 problem, but they are expensive and quickly becoming a scarce resource due to cobalt use in batteries, which account for half of the total cobalt consumption.
Hensen expects that the newly developed catalysts will also play an import role in the future energy and basic chemicals industry. The feedstock will not be coal or gas, but waste and biomass. Syngas will continue to be the central element, as it is also the intermediate product in the conversion of these new feedstocks.
The Latest on: Coal to liquid fuels
via Google News
The Latest on: Coal to liquid fuels
- Federal Labor MP Julie Owens declares coal can be phased outon November 27, 2020 at 1:51 pm
Federal Labor MP Julie Owens, who grew up in a mining town, has declared coal doesn't have a future because a little-known source of energy will be able to replace it.
- Origin Energy to add gas, batteries to its mixon November 26, 2020 at 2:08 am
Origin Energy will consider adding batteries and a fast-start gas plant to the countrys largest coal station, Eraring, and co-investing with partners alongside governments as it looks to accelerate ...
- Origin links with Japan giant Kawasaki in plan to export 'green' hydrogenon November 25, 2020 at 5:30 pm
As countries increasingly look to hydrogen as part of their 2050 carbon-reduction aims, Origin has been collaborating with Japanese manufacturing firm Kawasaki for a 300-megawatt electrolyser in ...
- Renewables, GOP supermajority loom large over energy and environmental groups’ 2021 state legislative prioritieson November 24, 2020 at 8:00 pm
New battle lines are being drawn in the state Legislature with renewables poised to seize a larger share of a West Virginia energy market where coal and natural ...
- As South Africa Clings to Coal, A Struggle for the Right to Breatheon November 24, 2020 at 2:24 am
Close ties between the ruling elite and the coal industry have helped perpetuate South Africa’s dependence on the dirtiest fossil fuel for electricity. But now residents of the nation’s most ...
- How NETL is helping find new purpose for coalon November 19, 2020 at 4:51 am
There may one day come a point when coal is mined just as much for its products as it is now for energy. The U.S. Department of Energy and the National Energy Technology Laboratory, which is based in ...
- Gains from gas-fired energy transition are too great to ignoreon November 17, 2020 at 7:59 pm
Why does the Grattan Institute want to deny Australia the benefits of a shift from coal to natural gas that will lower electricity prices, boost manufacturing, and reduce emissions?
- Fossil fuel support lands SA in the G20 dog boxon November 14, 2020 at 11:00 am
South Africa has been ranked the second worst performer of the G20 non-OECD member countries, behind Saudi Arabia, for its lack of transparency and continued support for fossil production, fossil-fuel ...
- Coal to Liquid (CTL) Market 2020-2024 | Rising Demand for Clean Fuel to Boost Growth | Technavioon November 9, 2020 at 4:00 pm
Rising demand for clean fuel has been instrumental in driving ... in CTL process as one of the prime reasons driving the coal to liquid (CTL) market growth during the next few years.
via Bing News