DECOMPOSITION OF CHLORINATED HYDROCARBONS
USING A NOVEL HIGH-TEMPERATURE FLUID WALL REACTOR
A. W. Hornig, Principal Scientist
Baird Corporation
Bedford, Massachusetts 01730
The proliferation of waste materials in our industrial society has created a severe problem
for safe and environmentally sound disposal. An acute subproblem is the disposal of increasing quantities of toxic and hazardous materials which are also very stable and difficult
to decompose. Examples are the polychlorinated hydrocarbons PCB and Kepone. It has become evident that burial in special sealed dumps is not a feasible long-range solution-at
most buying time. Thermal degradation of the materials in an environmentally sound
manner seems to be one of the possible useful solutions.
Federal regulations for the incineration of liquid PCB currently specify a temperature of
1200 C for a residence time of 2 seconds, or a temperature of 1600 C and a residence time
of 1.5 seconds. Not only are these temperatures unattainable in many incinerators, but the
extreme corrosivity of the chlorine (or HCL) emitted causes rapid deterioration of linings
and need for frequent, costly replacement.
This chapter presents the first results of a program to investigate the feasibility of using a
novel high-temperature fluid wall (HTFW) reactor for the specialized degradation of difficult
materials such as the halogenated organics, PCB, Kepone, etc. The HTFW Reactor [ 1 ],
developed and patented by the Thagard Technology Company of Irvine, CA, is attractive
because its unique operating conditions and design appear to circumvent the principal difficulties of standard incinerators while promoting the efficient degradation of these difficult
materials.
HIGH-TEMPERATURE FLUID WALL REACTOR
The HTFW reactor is a novel device that transfers energy to a reacting stream via radiation through a transparent gaseous envelope. There is no physical contact between the reacting stream and tne reactor's walls, which operate in the temperature range 1000-3000 C,
and little net pressure on the porous radiating core. Since the reactor is configured as a
blackbody cavity, all radiation not directly used by the chemical reaction or in heating the
reactants is returned to the radiator, resulting in an unusually efficient utilization of electrical energy.
The HTFW reactor is particularly suited to high-temperature reactions such as pyrolysis
and water-gas reactions. Because of the high-temperature capability, high pressures are not
necessary for completion of many of these reactions. Because the reactor is not dependent
on catalysts for its operation, the purity of its feedstock with respect to water, sulfur, metal
contaminants or inert filler is not important.
The prototype reactor consists principally of a cylindrical core made of a porous tube six
inches in diameter. A protective blanket of gaseous nitrogen or hydrogen is passed through
the porous tube walls. The core is heated to incandescence by an electrical heater constructed of graphite cloth. The core and electrodes are enclosed by a heat shield made principally of graphite which forms the blackbody cavity. These features can be seen in the
cross-section of Figure 1 and the schematic of Figure 2.
The fluid blanket protects the internal walls of the reaction tube from the reactants and
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