Furnaces – Process – Incinerating refuse
Patent
1994-11-18
1996-09-03
Kwon, John T.
Furnaces
Process
Incinerating refuse
110246, 110347, F23G 100
Patent
active
055513581
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a method of burning waste comprised essentially of plastic, especially PVC waste.
It is known (German Publication "Mull und Abfall", 6/84, Pages 169-175) to collect plastic, especially PVC plastic, separately from household refuse and to burn it in a combustion unit. In addition to being generated in household refuse, plastic also results as a residual product in industry, for example during the manufacture of windows and the like, during building renovation or the like.
During the combustion of waste that comprises essentially plastic in a combustion unit that is provided with grate firing, there exists the danger that due to the low melting point of the plastic waste, for example in a temperature range of 70.degree.-200.degree. C., molten plastic falls through the grating into the air boxes and is thus lost to the combustion.
It is an object of the present invention to provide a method of the aforementioned general type that essentially guarantees a more complete combustion.
SUMMARY OF THE INVENTION
This object is realized in that the waste comprised essentially of plastic (plastic waste) is burned in a revolving cylindrical furnace accompanied by the addition of at least one finely ground solid additive having at least one component with a melting temperature higher than the melting temperature of the plastic.
Due to the combustion in the revolving cylindrical furnace, and due to the addition of the finely ground solid additive, the pyrolysis phase during the combustion of the plastic (melting of the plastic, softening and partial combustion of volatile components and coking) are influenced in such a way that the coke that is formed does not cake up the revolving cylindrical furnace and has a looser structure that burns as efficiently as possible. This can essentially be attributed to the fact that after the plastic melts it becomes disposed upon the finely ground additive, thus making available a considerably greater surface area for the further steps of the pyrolysis phase. In other words, a coke structure is formed that leads to a substantially more complete combustion. It is preferred that such an additive be used that even at the end of the combustion the melting temperature of the at least one component is not reached. The temperature at the end of the revolving cylindrical furnace can, for example, be in the range of from 1100.degree.-1300.degree. C. The terminology "melting temperature of the plastic" in the specification and the claims also includes a temperature window, since with a mixture of various plastics one cannot expect a uniform melting temperature of the plastic components. The window can be between 70.degree. and 200.degree. C., but preferably between 80.degree. and 150.degree. C.
Due to the combustion in a revolving cylindrical furnace, an adequate retention time for the essentially uniform distribution of the softened or melted plastic upon the particles of the solid additive is ensured. Although the combustion of solid waste, especially specialty waste, industrial waste or the like, in a rotary kiln has already been proposed, with the general combustion of plastic waste caking and complete combustion problems can occur.
In a preferred manner, as the finely ground solid additive one or more additives from the following group are selected: quartz sand, fine gravel, stone chippings, bauxite, pure clay, oxidized ore, waste glass, granite, residue from combustion, especially slag, lignite, bituminous coal, especially highly volatile bituminous coal, asphalt road surface that has been reduced in size, chips of old tires.
With a portion of the aforementioned additives, in addition to the additives a fuel is also introduced into the process to enlarge the surface area in the event that the heating value of the plastic waste is not adequate by itself. With fuels an additional effect can be achieved in that the volatile constituents, by means of gasification, also contribute to a loosening of the coke structure and hence to a
REFERENCES:
patent: 3716339 (1973-02-01), Shigaki et al.
patent: 4846083 (1989-07-01), Serbent
patent: 4953481 (1990-09-01), Clayton
Von Dieter O. Reimann; Chlorverbindungen . . . PVC; Jun. 1984; pp. 169-176.
Burkhard Theo
Schmid Christoph
Sobolewski Hans
Kwon John T.
L. & C. Steinmuller GmbH
LandOfFree
Method of burning waste, especially PVC waste, comprised essenti does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of burning waste, especially PVC waste, comprised essenti, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of burning waste, especially PVC waste, comprised essenti will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1944675