Potential Applications of High Temperature Air Combustion Technology to Other Systems - High Temperature Air Combustion: From Energy Conservation to Pollution Reduction - page 355

turbine concept at present being developed at Nagoya University (Japan) is called the
chemical gas turbine. 13 This concept combines the conventional gas turbine combustion
technology and is based on converting the fuel to low molecular weight gases (and
hence called the chemical gas turbine) prior to combustion using high temperature air.
The combustion occurs under fuel-lean conditions. Limited studies on chemical gas
turbine combustion have shown good concept for chemical gas turbine, but data are
lacking under real engine-operating conditions. Further combustion challenges and
potential for gas turbine combustion are given in Reference 14.
A schematic diagram of gas turbine using high temperature air combustion is
essentially that shown in Figures 6.4 and 6.5 . In this gas turbine configuration most
of the heat from the exhaust gases is recovered and fed back into the furnace, boiler
or the gas turbine. In the proposed system the exhaust heat is recovered, using, for
example, a high efficiency heat exchanger and transported back to gas turbine
combustion chamber. A boiler or furnace may be utilized in conjunction with the
gas turbine to enhance overall system efficiency. The relative proportions of thermal
energy transported back to the furnace, afterburner, and gas turbine require careful
tailoring for the specific system under consideration.

6.8 PAINTS, OILY WASTES, AND HEAVY FUEL OILS

High temperature combustion technology offers significant potential for the thermal
destruction of waste paints, oily wastes, and other viscous hydrocarbons. The tech-
nology can also be developed for the clean and highly efficient combustion of heavy
fuel oils. At the time of writing this topic only very limited data are available on
heavy fuel oils using high temperature combustion air. 12 Much of the work on heavy
fuel oil using high temperature air combustion has been conducted in Taiwan and
Japan. Negligible to no data or experiences are available on waste paints using high
temperature air combustion technology, although we expect this topic to see progress
in the very near future. However, it can be expected that HiTAC should offer good
benefits for further development of this technology for waste paints, oily wastes,
and other viscous hydrocarbons.

6.9 FUEL CELLS

Steam reforming of hydrocarbons is attractive from the point of view of forming
increased amounts of hydrogen production at low cost. High temperature air com-
bustion technology has been demonstrated to be instrumental for providing higher
levels of hydrogen using steam reforming. High levels of hydrogen production at
the laboratory scale have been shown using characteristic features of high temper-
ature air combustion. The challenge here is to produce very large quantities of pure
hydrogen at low cost. It is expected that development efforts to produce hydrogen
at low cost will increase in the future. Another challenge would be to separate out
CO from the hydrogen produced. In the example given below, carbon (or hydrocar-
bon) is converted to useful chemical energy (CO and H 2 ) with the steam reforming
process. 15 The results of equilibrium calculation show that increased levels of CO