1. FIELD OF THE INVENTION
This invention relates to anti-pollution apparatus and in particular to thermal regeneration incineration systems which can meet increasingly stringent anti-pollution requirements.
2. PRIOR ART
Thermal regeneration equipment is known which comprises a plurality of heat-exchange beds or chambers in communication with a high-temperature oxidation zone such as is shown in U.S. Pat. No. 3,895,918 to James H. Mueller. In such equipment, the exhaust gas or effluent from a factory, for example, is purified by passing it through a first inlet bed into the high temperature zone where noxious or toxic components are oxidized to decomposition. These oxidized gases are drawn by an exhaust fan from the high temperature chamber through a second heat-exchange bed to exhaust into the atmosphere. The elements of the second bed have their temperature raised substantially by the hot decomposed gases passing through them.
In apparatus such as shown in the Mueller patent, the same beds may function in different ways in different cycles of operation, i.e., in one cycle a particular bed may function as an inlet bed to which the effluent is initially applied and in another cycle as an outlet bed to which the heat-decomposed effluent combustion products are passed. Control of the mode of the beds is accomplished by providing an inlet valve and an outlet valve for each of the sections containing the beds.
Because of the very high temperatures involved in such apparatus, most such valves are metal-to-metal. For various reasons, the seal afforded by these valves when in the nominally "closed" condition, may be less than perfect with the result that between cycles of operation, for example, the effluent from the factory may leak past the valves directly into the exhaust duct and out through the stack. In many cases, such leakage is not very significant, but when the effluent has highly toxic or corrosive components, even the slightest amount of leakage into the ambient atmosphere may pose dangers to people and property and provoke action by the authorities for breach of anti-pollution laws. If the effluent leaks so that it effectively by-passes the combustion chamber, the overall thermal efficiency of the system is affected adversely. Such leakage may also damage the valves and other components of the apparatus.
It is therefore among the objects of the present invention to provide a system for reducing or preventing leakage of gases in the system past nominally closed valves.
It is also among the objects of the present invention to provide apparatus for reducing pollution especially in thermal regeneration incineration systems.
Still another object of the invention is to provide thermal regeneration incineration apparatus with improved thermal efficiency.