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There are many misconceptions about clean coal technology. Here are some of the most frequently asked questions and Coalworks responses to them:
Q & A
Have commercial clean coal plants been built?
Yes, they have been built to commercial scale and are operating successfully. The website "Clean Coal Success Stories" refers to many of the clean coal plants featured on this page (click on "CLICK FOR MORE CLEAN COAL SUCCESS STORIES" below). We also have listed some of these plants in the panel to the left with each button linking to a photo demonstrating the commercial size of the plants.
Note: Coalworks has announced a strategic alliance with Synthesis Energy Systems Inc (Nasdaq:SYMX) to consider the feasibility of developing a gasification and liquefaction plant at its Oaklands project utilising SES proprietary U-GAS® gasification technology.
This plant would process coal mined from the proposed Oaklands Coal mine and cleanly convert it to petrol. This involves the coal being stockpiled before being fed into a gasification reactor to produce syngas. The syngas is then processed to produce petrol in the remaining process plant.
The clean coal plant allows removal of sulphur, nitrous oxides and carbon dioxide from the syngas using this commercially proven technology. U-GAS® technology has been proven on a commercial scale with gasification plants in China, for example, at Shandong Province in China- the Hai Hua plant which has been operating since January 2008. See www.synthesisenergy.com
CLICK FOR MORE CLEAN COAL SUCCESS STORIES
Cleaner electricity is being produced from these plants which are known as integrated gasification combined cycle power stations (IGCC plants) - see Gasification below.
What about their clean coal performance?
The Puertollano Plant which is the largest IGCC plant has published performance figures showing substantial reduction in CO2 emissions and other pollutants compared with present technologies.
Carbon Capture and Storage occurs in the oil industry but has it been applied to the coal industry?
Yes, there is a large coal gasification plant in North Dakota sequestrating CO2 and piping it to Canada where it is sequestrated in depleted oil fields. This large commercial plant has been operating CCS for several years. There is a misconception that the technology is unproven or untried and thus CCS research has commenced. It is not the technology that is in issue, it is the suitability of the sequestration sites and the improvement of existing technologies for sequestration that are targeted. In summary CCS works but specific sites require differing solutions.
GASIFICATION - THE KEY TO CLEAN COAL TECHNOLOGIES
Coal gasification is the process of converting coal to a gaseous fuel through partial oxidation. The coal is fed into a high-temperature pressurized container along with steam and a limited amount of oxygen to produce a gas. The gas is known as synthesis gas or syngas and mainly consists of carbon monoxide and hydrogen. The advantage is that when you gasify to produce syngas CO2 can be captured as part of this process. Furthermore even without CCS emissions from gasification are much lower. Syngas can be used to produce electricity, gas, or synthetic fuels or major chemicals such as methanol, ammonia or urea. The synthetic fuels are purer than the fuels that are currently derived from petroleum because gasification allows removal of contaminants such as sulphur and nitrogen oxides. The IGCC plants featured above all use gasification and have superior efficiency to conventional plants meaning they emit less CO2 per tonne of coal. Key advantages of Gasification:
- Cleanest of all coal based technologies
- Uses 30% to 40% less water
- Can remove contaminants such as mercury and sulphur
- Lowers SOx and NOx emissions
- A proven and reliable technology
- More direct route to making clean burning hydrogen
NEW GENERATION CLEAN COAL PLANTS
Conventional coal fired power technology which has operated at lower temperatures (called sub critical temperature plants) has advanced to the stage where super critical and ultra supercritical plants are now being introduced. These new generation plants have much higher efficiencies meaning that less coal is consumed per megawatt of electricity produced thus lowering CO2 emissions. In addition more efficient techniques of reducing sulphur, SOx, NOx and mercury emissions are applied. The new Kogan Creek power station in Queensland is an example of a supercritical power station. In addition it has applied dry cooling in favour of water cooling to drastically reduce water usage. In March 2008 the CSIRO signed an agreement with China's thermal power institute to build a post combustion CO2 capture n plant at Huaneng Beijing Co Generation Power Plant as a research project. This would also allow older power plants to be retrofitted and made "carbon capture ready".
SEQUESTRATION OF CO2
Carbon capture and storage (CCS) is currently being demonstrated by a large commercial coal gasification plant in North Dakota at the Great Plains Gasification Plant which gasifies brown coal , captures the CO2 and then sends it by pipeline for sequestration to a depleted oil reservoir in Alberta.
CLICK FOR COAL CCS - CO2 SUCCESS STORY
Oil and gas reservoirs are a prime target for sequestration but saline aquifers have also been identified as potential reservoirs which could chemically lock the CO2 in solution if the conditions are right. For example a saline aquifer in sandstone would lock such CO2 in like a sponge absorbing water.
COALWORKS CLEAN COAL STRATEGY
Coalworks has been promoting its coal due to its excellent gasification and low sulphur qualities making it attractive for users of clean coal technologies
Coalworks has also conducted testwork on briquetting coal which reduces moisture in an endeavour to lower the CO2 emission footprint of the coal
Coalworks has commenced discussions with the NSW Government concerning the possible construction of an IGCC plant at Oaklands designed to lower CO2 emission. Government advisers have singled out Oaklands as an ideal location for a power station and Oaklands coal is excellent for gasification and has low sulphur giving excellent potential for a clean coal power station
One of the candidates for sequestration sites are deep saline aquifers. The Oaklands Basin contains saline formations extending to at least 1300m depth, with significant mudstone sealing layers, and may therefore be suitable for carbon capture and storage.
COAL TO LIQUIDS POTENTIAL
A Coal to Liquids plant using gasification at Oaklandscould be built which is capable of producing various chemicals e.g. methanol, ammonia and liquid fuels. Methanol has a number of uses including use as a blend with biofuels.
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