What is Gasification?
Gasification Wood Boiler
Gasification is the thermal decomposition of organic material at elevated temperatures in an oxygen restricted environment. The process, which requires an initial heat supply to get underway, produces a mixture of combustible gases (primarily methane, complex hydrocarbons, hydrogen and carbon monoxide) called 'syngas'. Syngas can be stored or combusted as it is produced, giving the process a high degree of flexibility. Gasification enables biomass to be burnt very efficiently and in its most technologically advanced forms gasification can provide for carbon capture (carbon sequestration). This is a way forward in reducing carbon emissions which might also successfully combat climate change.
But, gasification has another use, other than energy production, and that is for the gas to be used as the starting point for the industrial/chemicals and refining industries, as a raw material in place of oil. As oil prices rise, gasification using low grade, and thus much lower cost, raw materials is becoming much more viable economically. The technique which was seen by many even five to ten years ago as expensive, and little more than a university and academic research subject, is now looking increasingly main-stream.
Investors like the fact that by using gasification and the un-glamorous non-stock exchange commodities low grade coal and tar sand biomass feed stocks typically used in large installations, the volatility recently seen in oil and natural gas prices can be avoided.
At the pinnacle of gasification technology is Integrated Gasification Combined Cycle (IGCC) technology. IGCC is the technology used at large scale by equally large companies like GEC for electricity generation. It is at the cutting edge of what high pressure and high temperature technology can provide, uses pure oxygen for super efficient gasification, and stands beside the atmospheric oxygen separation plant which feeds it, in turn using its own output to power its input. To see an IGCC plant working is an amazingly complex beast, a true wonder combining all of man's the latest engineering skills.
However, the wonder process that gasification can be goes even further. Not only is it a highly efficient method for obtaining energy from organic materials, it can be used as a method for disposing of waste. This is also an admirable attribute in these days of scarce and costly landfill disposal.
The process is not new though, and need not be driven by high technology in order to work. There is a long history of gasification going back many years. It was developed in the 1800s and was previously used to produce gas for lighting and cooking. Every town at one time had it own coking plant, and gasification was the process used to produce coke for fuel, and 'town gas' for piped distribution throughout the neighbourhood.
Unsurprisingly, due to the rapid recent oil price hikes, gasification use is growing everywhere. As we hinted earlier, the secondary step of using Fischer-Tropsch technology is seeing rapid uptake, to take the syngas and can convert it into ethanol, methanol, diesel, etc., and it has become a cheaper alternative to creating these substances from oil.
Gasification in all its variations - and it can be used to create many products (electric power, liquid fuels, hydrogen, synthetic gas) - also provides great opportunities for pollution control. Emissions from the process are inherently less problematic from this form of combustion when compared with incineration, and other methods of burning. Sulfur, nitrous oxides, and mercury are not generated to the same extent within flue gases so there is less efficiency-sapping energy needed to clean these emissions than in traditional systems.
But don't be deluded to think that gasification energy is necessarily green energy. Energy produced by this or any other process is not renewable energy unless the feedstock used is itself renewable biomass. In fact most gasification plants in the past were fossil fueled.
However, this is rapidly changing and for example wood gasification can be considered to be sustainable renewable energy as long as it is supplied by forests which are being managed by replanting all felling according to a proper management program.
Use of gasification by waste disposal operators can reduce dependency on landfill, and provide a replacement for energy previously provided by coal-burning power stations. Generating electricity from household waste by this method is a big step forward, and in the UK the government department DEFRA is funding technology demonstrations to show how well this can work, to prospective local authority waste engineers, councillor's and other decision makers.
Finally, we have yet another advantage of the process to tell you about. One form of waste that the emerging gasification technology has proven successful in treating is waste food, and in sterilising animal by-product food waste. During this process a carbonaceous food waste feedstock material is heated in a reducing atmosphere and this, with the high temperatures present, very successfully destroys pretty much all vectors of disease.
Gasification is the thermal decomposition of organic material at elevated temperatures in an oxygen restricted environment. The process, which requires an initial heat supply to get underway, produces a mixture of combustible gases (primarily methane, complex hydrocarbons, hydrogen and carbon monoxide) called 'syngas'. Syngas can be stored or combusted as it is produced, giving the process a high degree of flexibility. Gasification enables biomass to be burnt very efficiently and in its most technologically advanced forms gasification can provide for carbon capture (carbon sequestration). This is a way forward in reducing carbon emissions which might also successfully combat climate change.
But, gasification has another use, other than energy production, and that is for the gas to be used as the starting point for the industrial/chemicals and refining industries, as a raw material in place of oil. As oil prices rise, gasification using low grade, and thus much lower cost, raw materials is becoming much more viable economically. The technique which was seen by many even five to ten years ago as expensive, and little more than a university and academic research subject, is now looking increasingly main-stream.
Investors like the fact that by using gasification and the un-glamorous non-stock exchange commodities low grade coal and tar sand biomass feed stocks typically used in large installations, the volatility recently seen in oil and natural gas prices can be avoided.
At the pinnacle of gasification technology is Integrated Gasification Combined Cycle (IGCC) technology. IGCC is the technology used at large scale by equally large companies like GEC for electricity generation. It is at the cutting edge of what high pressure and high temperature technology can provide, uses pure oxygen for super efficient gasification, and stands beside the atmospheric oxygen separation plant which feeds it, in turn using its own output to power its input. To see an IGCC plant working is an amazingly complex beast, a true wonder combining all of man's the latest engineering skills.
However, the wonder process that gasification can be goes even further. Not only is it a highly efficient method for obtaining energy from organic materials, it can be used as a method for disposing of waste. This is also an admirable attribute in these days of scarce and costly landfill disposal.
The process is not new though, and need not be driven by high technology in order to work. There is a long history of gasification going back many years. It was developed in the 1800s and was previously used to produce gas for lighting and cooking. Every town at one time had it own coking plant, and gasification was the process used to produce coke for fuel, and 'town gas' for piped distribution throughout the neighbourhood.
Unsurprisingly, due to the rapid recent oil price hikes, gasification use is growing everywhere. As we hinted earlier, the secondary step of using Fischer-Tropsch technology is seeing rapid uptake, to take the syngas and can convert it into ethanol, methanol, diesel, etc., and it has become a cheaper alternative to creating these substances from oil.
Gasification in all its variations - and it can be used to create many products (electric power, liquid fuels, hydrogen, synthetic gas) - also provides great opportunities for pollution control. Emissions from the process are inherently less problematic from this form of combustion when compared with incineration, and other methods of burning. Sulfur, nitrous oxides, and mercury are not generated to the same extent within flue gases so there is less efficiency-sapping energy needed to clean these emissions than in traditional systems.
But don't be deluded to think that gasification energy is necessarily green energy. Energy produced by this or any other process is not renewable energy unless the feedstock used is itself renewable biomass. In fact most gasification plants in the past were fossil fueled.
However, this is rapidly changing and for example wood gasification can be considered to be sustainable renewable energy as long as it is supplied by forests which are being managed by replanting all felling according to a proper management program.
Use of gasification by waste disposal operators can reduce dependency on landfill, and provide a replacement for energy previously provided by coal-burning power stations. Generating electricity from household waste by this method is a big step forward, and in the UK the government department DEFRA is funding technology demonstrations to show how well this can work, to prospective local authority waste engineers, councillor's and other decision makers.
Finally, we have yet another advantage of the process to tell you about. One form of waste that the emerging gasification technology has proven successful in treating is waste food, and in sterilising animal by-product food waste. During this process a carbonaceous food waste feedstock material is heated in a reducing atmosphere and this, with the high temperatures present, very successfully destroys pretty much all vectors of disease.
Steve Evans is an energy expert and leading engineer in the
promotion of gasification technology. We suggest that you continue now
to his web site Gasification for Energy
in its wide range of forms from low-tech as in gasification of wood to
high tech IGCC
[http://gasification4energy.com/IGCC-is-the-Best-Way-to-Burn-Solid-Fuels-for-Energy.php],
and small scale to the very largest.
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