Coal Gasification and the Gasification of Biomass
Coal gasification has the potential to answer most of the problems of coal power stations and to see us through until improved renewable energy technologies can be developed to replace the use of coal as a main base-load power gernation fuel in many of the world\'s nations.
It offers the most versatile and cleanest way to convert coal into electricity, hydrogen, and other energy forms. Furthermore, the first coal gasification electric power plants are now operating commercially in the United States and in other countries.
New gasification power stations are, for example, planned for the United Kingdom and many experts predict that coal gasification will be the core technology of the future generations of clean coal technology plants for several decades to come.
US experts have recently confirmed that far from the idea of carbon capture and storage being unproven, there are many examples in nature of carbon storage, and that carbon from the atmosphere is already effectively stored in huge quantities underground across the globe, completely naturally.
Carbon capture and storage (known as CSS) will therefore work for man as it already has done in nature, and the gasification process is the one to use when power stations also need to capture carbon. The reason for this assertion is it lends itself to the reactions needed to remove the carbon dioxide from the combustion gases before they are emitted via the chimney or flue.
Now lets take a step back to consider how gasification has been used in the past. Coal based "gas works" in huge numbers around the world produced manufactured “town” gas from the early nineteenth century through the mid-twentieth century. In fact it preceded the natural gas which has since the 1960s replaced town gas in our gas grid distribution systems. Coal gasification was used in the 1700\'s in England, France and Germany for street lanterns. During World War I small gasifiers were even developed to operate vehicles, boats, trains and electric generators.
So, the commercial utilization of manufactured coal gas pre-dated that of natural gas due to the comparative ease of producing coal gas.
Coal gasification still has economic potential with high oil prices in mind, however, there are some drawbacks. There are a number of technical challenges to the power engineers in making the process work reliably, and in particular slagging must be dealt with to prevent the bed of coal from fusing.
These problems are now being overcome the US and international conglomerate GE has been saying for some years that it has the technology tamed, and in Europe the public funding of some flagship IGCC plants has enabled the technology to advance to maturity. The result is that most believe that coal will most likely be the principal source of syngas in the short-term future.
However, before, you say, what about the possible polluting and greenhouse gas producing effects of this? Let me stress that the sulfur, metals and other impurities in coal which have been causing pollution, and the solid residues from the gasification process which were often toxic, are now removed from the gases before they are discharged. Former gasworks sites are often contaminated with hazardous wastes, but this will certainly not be the case for the new plants.
Coal gasification involves the combustion of some of the carbon in the coal to produce the heat that makes the process work. By-products of this carbon combustion which will now be collected greenly are carbon dioxide, ash, and sulfur, all of which in their uncontaminated modern forms will have a market value and may be separated for sale. Meanwhile the provision of CSS (which I would rather not call “carbon sequestration" although many call it that) will avoid these coal burning systems contributing to global warming.
Once the technology of gasification becomes mature it will then be possible to take the whole thing one stage further to use gasification to produce energy from renewable carbon fuels which are continuously regrown, known a biomass
Biomass gasification extends the idea very well demonstrated in gasifying wood stoves. Indeed, there are a number of products now on the market using a huge range of available fuels, not just wood. In its current state the use of biomass, is open-source and grassroots, but it is fat becoming a mainstream power generating source.
Look out for biomass energy plants over the next few years. These are the renewable energy future for society, rather than coal which will eventually be used up in any event, even if there were no problems of climate change.
About the Author
Steve has built a great web site where there are a lot more facts about gasification. This is a hot subject indeed for this technology which has become an essential read for all those who appreciate renewable energy issues and are interested in taking action to reduce the impact of climate change.
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