The first gasifiers were known as gasification retorts and they have been around for well over a century providing our town gas supplies from coal. In basic terms they involve a container in which combustible fuel is heated, driving off flammable hydrocarbon gases. These gases are then scrubbed in filters to remove particulate matter and any corrosive chemicals, before being plumbed into anything from the towns gas supply to a modified carburettor to fuel a standard internal combustion engine.
Gasifiers are available now. They are proven technology. They can and are helping in the war to reduce gas and electricity prices, and the magic thing is that the same principle can be applied to many fuels other than coal.
These systems are capable of producing electricity from any biomass source. They may use any fuel in some, such as coal, petroleum coke, residual oil, oil emulsions, tar sands, and / or other similar fuels. Gasifiers produce a gas which is commonly known as syngas. This gas is used mostly where it is created to power a gas turbine. Gasification uses chemistry and high temperature and pressures to change the way the coal or other form of solid carbonaceous (fossil) fuel produces heat. In other words instead of burning the fuel outright, a gasifier part burns the fuel due to the presence of only a limited amount of oxygen and creates a fuel gas.
One gasifier, for example, is a device that has been developed by TERI (The Tata Energy Research Institute in India) for use in the drying of cardamom. The gasifier uses briquettes that are made from firewood and other types of biomass and turns them into a gas that burns with a clean smokeless flame.
In another example a gasifier is the key component in the Ag Bio-Power Energy System, but it is not the only component. In the patented configuration of the system, solid wastes containing metals and other non-combustible materials are burned separately while a gasifier is used as a scrubber for the polluting emissions because gasification is so good at burning out these substances.
It is reported that Household and Commercial Waste can also be gasified. In this case combustible gases are used within the system for increased efficiency and high temperature combustion than is archived in an incinerator. After gasification the residue of thermal decomposition is cooled and rough particles such as metals and non-combustibles are separated by means of a vibrating sieve and magnetic separator. The separated fine particles are mostly ash and carbon content, and these particles can then be crushed and sent to the final furnace for vitrification, where they are turned into essentially a form of glass, safely binding in any toxic substances, out of harm's way, for ever.
Combustible waste from industrial production processes which is reported to be suitable for gasification includes textile waste, wood scrap / trimmings, plastic scrap, and non-reusable solvents. Textile waste can consist of excess yarn, thread, cloth, carpet, or any other fabric. Combustion temperatures of 1500-1600 ~ F and heat release rates of about 400,000 Btu / cu ft / hr are possible and give heat transfer rates reported to be larger than those of conventional pulverized coal boilers.
Some of these technology providers are claiming cell microturbine combinations are possible which have the potential to achieve up to 60 percent efficiency and near-zero emissions. On top of that they say that fuel flexibility enables the use of low-cost indigenous fuels, renewables and waste materials. Even, for example, experts say briquettes produced from agricultural residues can be used in some gasifier models.
Some gasifier plant is now also being developed which is based on fluidized bed technology with the possibility of the common and low cost availability of practically zero emissions release systems achieving high efficiencies using a host cheap, locally produced, renewable fuel sources.
Now, we think that this is pretty cool, when at present all we can see is rapidly rising gas prices and practically no alternatives for me and you, but to pay them.
Reducing energy demand, especially in the sense of better insulation for heating homes and offices, is of course, more of a potential for saving CO2 emissions, but that's not what what we are discussing in this article.
We have been here before, as well, in that in the mid to late 1970s, when it was believed that there was going to be a shortfall of oil due to the formation of OPEC, fuel prices rose excessively. At that time also there was an expected decline in supplies, and considerable effort went into developing alternatives. But, those efforts came to very little, as in real terms the alternatives were still more expensive than the oil and coal based alternatives. This time around that is no longer the case, so expect to hear about more suddenly "cool" energy solutions, but which are also very "hot" indeed – at the same time!