Furnaces – Process – Treating fuel constituent or combustion product
Patent
1995-12-04
1997-12-16
Bennett, Henry A.
Furnaces
Process
Treating fuel constituent or combustion product
110346, 110215, 110204, F23J 1100
Patent
active
056973071
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
When operated properly, incinerators can achieve high efficiency in destroying hazardous organic materials in treating both hazardous wastes and mixed wastes. However, problems arise during improper operations or upset conditions, when dioxanes, furans, and other toxic materials may be released at dangerous levels. By means of careful design and operation, which are regulated by the Environmental Protection Agency, and various state and local agencies, dangerous emission levels can be avoided.
Fluid bed incineration for hazardous organic waste is an old concept and has been practiced for years by several companies, one of which being the Doff-Oliver Company. In the June, 1992 edition of "Chemical Engineering Progress", John F. Mullin of the Dorr-Oliver Company reviewed the waste incinerator designs used to treat hazardous waste over the past fifteen years. Examples of the Dorr-Oliver technology are included in the Fitch et al. U.S. Pat. No. 4,159,682 issued Jul. 3, 1979 showing separate dryer and incinerator fluid beds wherein the dryer off gases are handled separately from the incinerator off gases and hot bed material from the incinerator is used to heat the moist feed material to the dryer. However, the Fitch et al. '682 patent vents incinerator off gases to the atmosphere. Another Dorr-Oliver patent is the Fitch et al. U.S. Pat. No. 4,232,614 issued Nov. 11, 1980, which also teaches separate air dryer and incinerator mechanisms, both of which have off gas streams which are treated separately but which eventually exit the system to the atmosphere.
Another company that has been active in the incineration of hazardous waste material was the Envirotech Corporation of Menlo Park, Calif., later bought by the Lurgi Company. However, in the 70's and early 80's, the Envirotech Company operated a number of systems in an attempt to treat sewage sludge and industrial waste. Representative systems include rotary kiln systems and multiple hearth systems which were used to classify and dry sludge and thereafter incinerate same, for instance see the Isheim U.S. Pat. No. 4,153,411, the Isheim U.S. Pat. No. 4,248,164, the Lombana U.S. Pat. No. 4,215,637. There are other patents issued to Envirotech which are also pertinent; however, none of these patents relate to systems in which no vapor emissions exit to the atmosphere.
Briefly, other companies through the years, have used fluidized bed systems which treat hazardous organic compounds inherent in the operation of the system. For instance, the Foster-Wheeler Energy Corporation developed significant technology relating to the fluidized bed treatment of coal as for instance in the Daman U.S. Pat. No. 4,275,668 issued Jun. 30, 1981, the Taylor U.S. Pat. No. 4,197,086 issued Apr. 8, 1980 and other Foster-Wheeler patents of this general time frame; however, none of the Foster-Wheeler systems and processes to the knowledge of the applicants included systems which are unvented to the atmosphere. Combustion Power Company in Palo Alto, Calif. investigated fluidized bed separation and incineration, see the Smith et al. U.S. Pat. No. 3,654,705 issued Apr. 11, 1972. A large waste incinerator was operated in Palo Alto in the 1970's and this may have been a precursor to such system. Other representative technologies in the hazardous waste disposal business include rotary kilns useful for incineration and such processes were routinely practiced throughout the United States in the 70's and 80's for incinerating waste including hazardous waste of both solid and liquid, but all of these incineration technologies involve venting off gases to the atmosphere.
Finally, there is a rotary kiln process which has been successfully used to remediate PCBs at Waukegan Harbor, Ill. and at Wide Beach, N.Y., which produces a reduced amount of off gases from the remediation, represented by the Taciuk U.S. Pat. Nos. 4,180,455, 4,280,879, 4,285,773 and 4,306,961. However, the Taciuk process still produces significant quantities of vapor which has to be treated by down stream
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Nelson Paul A.
Swift William M.
Bennett Henry A.
The University of Chicago
Tinker Susanne C.
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