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Study finds co-producing FT fuels and electricity from coal and biomass with CCS delivers low GHG synfuels at lower cost and with less biomass than cellulosic ethanol

Liuftl
Greenhouse has (GHG) index (top) and GHG avoided values for all 16 Fischer-Tropsch liquids systems analyzed along with those for ethanol (with and without CCS). GHGI of 1 is equivalent to fossil-fuel products. Credit: ACS, Liu et al. Click to enlarge.

A detailed study by researchers from China and the US has concluded that Fischer-Tropsch synthetic liquid fuels (FTL) are typically less costly to produce when electricity is generated as a major coproduct than when the plants are designed to produce mainly liquid fuels.

Furthermore, coproduction systems that utilize a co-feed of biomass and coal (CBTL) and incorporate CO2 capture and storage (CCS) in the design offer attractive opportunities for decarbonizing both liquid fuels and power generation simultaneously. Such co-production systems, when considered as power generators, can provide decarbonized electricity at lower costs than is feasible with new stand-alone fossil fuel power plants under a wide range of conditions, according to the study by Liu et al. published in the ACS journal Energy & Fuels.

At a plausible GHG emissions price of $50/t CO2eq under a future US carbon mitigation policy, such co-production systems competing as power suppliers would be able to provide low-GHG-emitting synthetic fuels at the same unit cost as for coal synfuels characterized by ten times the GHG emission rate that are produced in plants having three times the synfuel output capacity and requiring twice the total capital investment. Moreover, the low-GHG-emitting synfuels produced by such systems would be less costly and require only half as much lignocellulosic biomass (or less) to produce as would cellulosic ethanol.

This strategy depends on the viability of CCS as a major carbon mitigation option, but all system components for the first generation of the required conversion technologies (including carbon capture components) are proven technologically, so that commercial-scale projects for co-production plants with CCS that have modest biomass input rates (~ 10%) could be demonstrated during this decade.

—Liu et al.

The team used detailed process simulations, lifecycle greenhouse gas emissions analyses, and cost analyses in a comprehensive analytical framework to assess 16 alternative system configurations that involve gasification-based coproduction of Fischer-Tropsch liquid (FTL) fuels and electricity from coal and/or biomass, with and without capture and storage of byproduct CO2.

The analysis found that 9 of the systems in the study—including two cellulosic ethanol systems (with and without CCS) have greenhouse gas index (GHGI) numbers of less than 0.20, and represent low-carbon transportation fuel options. The GHGI represents lifecycle GHG emissions associated with the facility divided by lifecycle emissions for production and use of an LHV-equivalent amount of fossil fuel-derived products displaced—i.e., a GHGI of 1 would represent lifecycle GHG emissions equivalent to that of fossil-fuel derived products.

The study also found that both BTL-RC-CCS (biomass-to-liquids, with recycling of unconverted syngas to maximize FTL output and CCS) and cellulosic ethanol with CCS (EtOH-CCS) have negative GHGI emission values that can be exploited to offset GHG missions from difficult to decarbonize energy sources such as transportation fuels derived from crude oil.

The team also observed that GHG Avoided [GHGA = (1 - GHGI)·(lifecycle GHG emissions for the displaced fossil fuels] for BTL-RC-CCS is 56% higher than that of EtOH-CCS largely because 56% of the biomass carbon is stored underground for BTL-RC-CCS compared to only 15% for EtOH-CCS.

Resources

  • Guangjian Liu, Eric D. Larson, Robert H. Williams, Thomas G. Kreutz and Xiangbo Guo (2010) Making Fischer-Tropsch Fuels and Electricity from Coal and Biomass: Performance and Cost Analysis. Energy Fuels, Article ASAP doi: 10.1021/ef101184e

Comments

HarveyD

More and studies studies.... to produce more liquid fuels?

HarveyD

Forget my comments above.

Roger Pham

And H2 also, from gasification of coal or biomass. H2 will be far more efficient than liquid fuel in FC and FCV's.

Gorr

'' Study finds co-producing FT fuels and electricity from coal and biomass with CCS delivers low GHG synfuels ''

The article is wrong, the chatters and journalists are wrong, the refiners are wrong, the stupid scientifics also, LOL' LOL' LOL, and into the dark. They just have to feed the co2 expels into harvesting and feeding and heating green algae fuels instead of releasing the co2 into the atmosphere like the do actually.

It's only a money gimmick this website, LOL.

Mannstein

According to a latest Daimler report liquid fuels will continue to play a major role in the trucking transportation sector for the foreseeable future.

This is good news since liquid biofuels will not be sufficient to meet the demand.

SJC

This is the energy plant idea, let the plants absorb the CO2, make fuel and electricity then use the CO2 for more fuel.

Engineer-Poet

While I'm not surprised that adding bio-carbon to a system with CCS can yield liquid fuels with minimal carbon emissions, I think we should be aiming higher than that. Using nuclear heat to gasify waste and sequestering the CO2 fraction is going to be more sustainable than anything running on coal.

Henry Gibson

It is now necessary to start reducing the cost of liquid fuels with their production from coal. Carbon capture is already being used, but it is not necessary because super-ultra safe CANDU reactors can generate the electricity now being produced by coal, and the coal is then used to make fuel.

Pebble bed reactors have a high enough temperature that they can combine water and CO2 into liquid fuels in the future. There is little reason to avoid liquid fuels if they are made from CO2 collected from the air or other standard sources. The large ship engines operate more efficiently and at less cost than most fuel cells, and hydraulic hybrids use the energy with double efficiency. These engines use fuels that have avoided high refining costs and CO2 and energy losses. People demand fuels and energy and it is they not the energy companies that are putting CO2 into the air. ..HG..

richard schumacher

Peachy! except for the small problem that CCS on the scale required may be physically impossible.

We still need liquid fuels for a long time to come, but making them from coal is an unsustainable solution.

SJC

I favor biomass over coal, but if coal gets us off OPEC oil I am all for it.

Engineer-Poet

Carbon separation is an integral part of syngas processing for F-T (the H/C ratio has to be adjusted, and contaminant acid gases like H2S removed; amine scrubbers get CO2 along with the H2S). Steam-stripping of the amine produces a nitrogen-free stream of H2S and CO2. This is a necessary part of the process, there's no way around it.

Piping this captured gas to storage somewhere is a cost, but small compared to the energy burden of trying to scrub CO2 from the exhaust gas of a powdered-coal boiler.

Reel$$

Moreover, the low-GHG-emitting synfuels produced by such systems would be less costly and require only half as much lignocellulosic biomass (or less) to produce as would cellulosic ethanol.

Sure sounds like a coal company talking.

Aussie

If the feedstock was all biomass then CCS shouldn't be necessary since the carbon was already in the biosphere and would be mostly recycled. The addition of coal sounds like a greenwash maybe to confuse the carbon tax people. Note that coal is plant material that accumulated over millions of years and biomass is realtime. Therefore coal has to be cheaper until it runs out.

It would be good if FT could be done small scale to use local crop wastes and heat or electricity used nearby. Therefore the next step seems to be either
1) get CCS to work with large scale coal + biomass
2) get small scale FT to work with biomass alone.

Engineer-Poet

A biomass-fuelled system with CCS would be carbon-negative.

SJC

Yes, that is the idea.

Fred H

"Peachy! except for the small problem that CCS on the scale required may be physically impossible.

We still need liquid fuels for a long time to come, but making them from coal is an unsustainable solution.

Posted by: richard schumacher"


It's not a question of "either or". No one is proposing to make all liquid fuels from coal. There is no single solution. We need a combination of different sources and improved efficiency to meet demand most economically and safely.

Yes it's not sustainable, but it is more sustainable. It is not realistic to jump straight to 100% sustainability. We will have to make several steps along they way to the ultimate goal of full sustainability.

That said, I must admit that I also don't like coal. I'd rather we left as much as possible in the ground. But realistically that's just not going to happen, so at least we should try to make the most of what we do dig up.

SJC

Ethanol from Coal, Natural Gas and Coke, not from Corn

http://www.energytribune.com/articles.cfm/5870/Ethanol-from-Coal-Natural-Gas-and-Coke-not-from-Corn

SJC

Here is another good presentation of the coal and natural gas to ethanol process.

http://www.coalplantsengineering.com/Ethanol-from-Coal-and-Natural-Gas1.pdf

Engineer-Poet

(strange, my response didn't appear. reposting!)

Get off the corn ethanol rant.
I'll be happy to, when the RFA demands that the blend mandate and blender's tax credit be repealed and ethanol from cellulose becomes cheaper and more abundant than ethanol from starch.
100 million cellulose FFVs will go much further towards reducing oil imports than 1 million EVs.
Production of cellulosic ethanol is now expected to be about 6.5 million gallons per year. That is 0.065 gallon (about one cup) of ethanol per vehicle over your 100 million FFVs, and would drive the typical 20-MPG-on-ethanol vehicle about 1.3 miles per YEAR.

Each Chevy Volt, driving 10,000 electric miles per year at an avoided 1/35 gallon/mile, saves 286 gallons of fuel per year. Saving 6.5 million gallons a year requires less than 23,000 vehicles. Each Leaf, iMiev and Focus EV will probably achieve similar figures.

The electrics are coming. They come not to be compatible with the petroleum-powered system, but to bury it.

The coalplantsengineering link is crazy. Ethylene is energetically uphill from methane and carbon.

SJC

Fred,

What you say makes sense, we could use more rational discussion like yours here. Unfortunately the arguments usually turn into all or nothing at all. The statements are made that we can not run ALL our cars on ethanol, so forget it. Everyone should buy an EV and if they do not they get what they deserve. That is not a very enlightened viewpoint.

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