Swedes Building Oxyfuel Clean Coal Pilot Plant

Stockholm-based Vattenfall AB has ordered the first components for a 30 megawatt US$50 million (40 million euro) oxyfuel pilot plant, with construction to start next year. The plant will be built at Schwarze Pumpe, south-east of Berlin where they operate a conventional coal-fired power plant. 

The plant will burn coal in a pure oxygen environment producing a flu gas that is mostly carbon dioxide and water.  The water can be condensed and the remaining nearly pure carbon dioxide collected for sequestration.   Nitrogen in the combustion air dilutes the oxygen in conventional coal furnaces, limiting the combustion temperatures, while In a oxyfuels furnace, the flu gases are recirculated to limit the oxygen concentration, producing the same effect.  An integrated cryogenic oxygen plant will be built as part of the pilot plant. 

Vattenfall's strategic director and oxyfuels project manager, says gasification, which is the main competing technology, is not ready to be a source of clean coal power. He cites mechanical difficulties that have plagued the gasification demonstration power plants built to date.

The development of advanced steam technology is not specifically linked to the CO2 capture field but more in general to the development of materials for extremely high pressures and temperatures, in combination with new boiler and turbine designs. During the 1990’s, power plants were built with very advanced steam data, such as Vattenfall’s lignite-fired units in Germany. Plant efficiencies (LHV) of over 49% have been obtained without CO2 capture.

One of the main opportunities with oxyfuel recycle combustion of coal in new plants is that the steam cycle is able to take advantage of the ongoing development to increase steam cycle efficiency through the use of advanced steam technology and lignite drying. The development of advanced steam technology is not specifically linked to the CO2 capture field but more in general to the development of materials for extremely high pressures and temperatures, in combination with new boiler and turbine designs

During the 1990’s, power plants were built with very advanced steam data, achieving efficiencies above 49%.  For the ferritic materials used in these power plants the limit for the materials lies just above 600°C.  Vattenfall is one of the 35 companies taking part the AD700 project which has a long-term target after year 2020 of a net efficiency above 55% (without CO2 capture) based on steam temperatures above 800°C. AD700 covers new materials (Ni-based superalloys, austenitic steels), new materials manufacturing methods and new welding methods.

Raw lignite contains roughly 50% of moisture, meaning that a non-negligible amount of the heat released during combustion is employed to evaporate water. Future lignite-fired plants will probably include lignite drying by using low-temperature heat from the steam power cycle or the flue gas.

The heat loss with the flue gas in a conventional air-fired boiler amounts to up to 10%. A significant part of this loss is the heat energy that leaves with the nitrogen in the flue gas. In the oxyfuel combustion boiler, there is no bulk nitrogen in the gas path, which in turn means that the heat losses with the flue gas can be significantly reduced.

Resources:

Oxyfuel Combustion for Coal-Fired Power Generation with CO2 Capture - Opportunities and Challenges, Kristin Jordal et al, Vattenfall Utveckling AB
Simpler and Cheaper Clean Coal Technology, Technology Review, April 26,2006

Technorati tags: coal, electric power, energy, technology

Comments

[New Reader]

This is only tangentially related, so I apologize.

But I was wondering if you could post something on conversion of CO2 to methane. I read recently that research is being conducted that hopes to convert sequestered CO2 to methane, then burn the methane for power, creating more CO2, convert to methane, etc.

Also, I was wondering if you could provide your thoughts on how coal can be extracted in a more environmentally-friendly manner. Even if coal plants start sequestering CO2, it seems like ramping up production means destroying the environment via extraction.

[Jim Robb]

re:Program to Mitigate the Consumption of Oil

Why not add a higher sales tax for vehicles that get poor MPG? I'm thinking about light trucks, SUVs and passenger vehicles.

And remove the tax incentive for businesses purchasing heavy SUVs.

[Robert McLeod]

New Reader:

You cannot violate conservation of energy. Sure you can create CH4 from CO2 but the process will be endothermic.

[amazingdrx]

Yep new reader, convert coal to fuel right underground with electric plasma drilling. The same with oil/tar sands.

The electric power coming from huge wind machines. Vaporized and liquified fuel is extracted and refined in one step.

This eliminates the massive use of water in most schemes and stores the wind power in the form of fuel. The problem is that it still produces CO 2.

The latest electric car to come on the market, mentioned in an article here, uses a lithium ion phosphate battery that stores the equivalent transportation energy to a gallon of gas at a weight of only 75 pounds.

That makes electric cars match the utility of liquid fueled vehicles. The weight of batteries and electric motor compares favorably to the weight of the internal combustion equipment it replaces. With zero emissions.

A lithium ion nano phosphate quick charge (5 minutes to 90% charge)battery with an even better power to weight ratio is under testing in cars right now, by Subaru and Altairno in Nevada.

That makes liquid fuel unecessary for vehicles. Wind, water, and solar power can provide the energy needed to charge these cars.

Forget coal, oil, tar sands, use the wind power directly. Electric cars have an order of magnitude fewer moving parts than internal combustion vehicles, making them much cheaper to manufacture.

Mass production of batteries, PV cells, geothermal heat pumps, wind, solar, and water powered generating equipment will vring the cost down to a much lower level than we pay for energy now.

Wind is already down to 2 cents per kwh, that equates to about 20 cents per gallon gasoline. Back to 50s prices.

Charge your car from your own home solar and wind installations and drive free, once the few years payback period is over.

Oh yeah, and CO 2 to methane? a process already exists and is under testing right now that uses algae in solar collectors to convert CO 2 and other power plant emissions to liquid fuel and methane.

[Big Gav]

amazingdrx - while CO2 to algae conversion is a neat development it still seems to be an incremental improvement to me - the carbon dioxide from the power plant still gets released - you just get a second bite at the cherry before it makes it into the atmosphere.

So its better than the current state of affairs but not really sustainable if you anticipate ever growing power consumption...

[amazingdrx]

That's true Gav. I like pure renewable electric power much better. Forget all combustion, except an ocasional campfire.

But if one needs liquid fuel, algae maybe the cleanest source. Until battery technology improves to 8 pounds per electrical equivalent of a gallon of gas, air travel will still require liquid fuel.

The best current manufactured battery appears to weigh around 70 pounds per gallon of gas equivalent. But research is getting very close to that 8 pound benchmark.

But burning coal or oil? That's just global suicide based on greed and ignorance.

[another new reader]

Dear new reader,
I think what you are talking about is extracting methane from abandoned coal mines by injecting CO2. This is somewhat similiar to EOR (enhanced oil recovery) process where CO2 is injected into oil mines to enhance oil recovery. However, for coal bed methane process (assuming that you are refering to it), captured CO2 is injected into old and abandoned coal mines (most of which still contain signifcant amount of coal) which displaces methane trapped between the coal seam and is eventually taken out for energy production.It is not at all concerned with converting CO2 to methane.

[Sandeep]

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