Furnaces – Utilizing powdered fuel – Having rotary flow means
Utility Patent
1999-07-13
2001-01-02
Ferensic, Denise L. (Department: 3749)
Furnaces
Utilizing powdered fuel
Having rotary flow means
C110S213000, C110S265000
Utility Patent
active
06167818
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an improved cyclone deflector cone and orifice member which is mounted to the re-entrant throat of a cyclone furnace to enhance the combustion performance within the cyclone furnace and the exit area of fuel-air particles at the re-entrant throat of the cyclone furnace.
The present invention is an improvement over my U.S. Pat. No. 4,473,014, which issued in my name on Sep. 25, 1984. As described in U.S. Pat. No. 4,473,014, a re-entrant throat extension member is adapted to be fitted to the re-entrant throat of a cyclone furnace/boiler to increase the residence time of the fuel-air mixture within the cyclone boiler assembly and to provide for enhanced combustion of the fuel-air mixture. The re-entrant throat extension member contemplated in accordance with U.S. Pat. No. 4,473,014 is an extension member having a plurality of fluid cooling tubes positioned therein which maintain the cyclone furnace within a controlled operating temperature range. The throat extension member increases the residence time of the fuel-air mixture within the cyclone furnace to provide improved combustion of the fuel-air mixture. However, a cooled re-entrant throat extension member oftentimes does not possess satisfactory properties, such as, resistance to thermal conductivity, resistance to abrasion, resistance to slag, resistance to thermal shock, resistance to oxidation and reducing atmospheres and resistance to carbon monoxide attack. Moreover, the '014 re-entrant throat extension member may not provide the shape and dimensional accuracy necessary to provide the proper deflection of and recycling of fuel particles toward the forward end portion of the wall surface of the cyclone chamber. Thus, the water-cooled re-entrant throat extension member may limit the proper distribution and dispersion of fuel particles through the cyclone.
Finally, the resultant time and costs necessary in retrofitting a cyclone boiler re-entrant throat extension member with water cooling tubes results in significant shutdown time of the cyclone furnace and is very costly. Moreover, the metal water tubes may result in degregation of the extension member after prolonged usage and performance impedance in water circulation in conventional cyclone furnaces.
SUMMARY OF THE INVENTION
It is one object of the present invention to provide re-entrant throat refractory deflector cone and orifice member which possesses improved thermal conductivity and abrasion resistance when installed within a cyclone furnace.
A further object of the present invention is a deflector cone and orifice member which is comprised of a refractory material which possess improved resistance to slag and thermal shock during operation of the cyclone furnace.
Yet another object of the present invention is to provide an improved deflector cone and orifice member which is comprised of a castable refractory material which possesses the requisite integrity of the deflector cone and orifice member shape and which is structured to be retrofitted to the re-entry throat of a cyclone boiler.
It is still another object of the present invention to provide a deflector cone and orifice member which is comprised of a castable ceramic refractory material which is selected from a group comprising chrome containing alumina, zirconia, metals, ceramics and mixtures or blends of these materials.
In accordance with the present invention, the deflector cone and throat member is sized to fit the internal diameter measurements taken of the re-entrant throat of any known cyclone furnace or boiler. After the size, width and dimensions of the re-entrant throat are known, a mold is made to provide the shape of the deflector cone and re-entrant throat member. The shape of the mold provides a monolithic cone having, preferably, more than one segment which are structurally arranged to be fitted together to provide a cylindrical re-entrant throat member and which are self supporting within the re-entrant throat portion of the furnace chamber.
The mold is adapted to receive the castable refractory material and the resultant molded deflector cone and re-entrant throat member consists of two portions, the first portion which forms the cylinder which is adapted to be received within the re-entrant throat of the cyclone furnace and a second portion which is an extension of the throat portion of the cone projecting into the furnace chamber at an angle substantially towards the end corner of the cyclone furnace. The angle of the second portion of the cone within the cyclone furnace ranges between approximately 15° to 20° from the central axis of the furnace. A preferred angle of approximately 17° is desired depending upon the slope of the re-entrant throat. The angle of the second portion away from the central axis is substantially the same as the angle of the re-entrant throat portion towards and with respect to the central axis. Such a relationship provides for the desired retention of the fuel-air mixture within the cyclone furnace to provide enhanced combustion within the furnace chamber.
One significant advantage of the present invention is the capital savings realized when using a deflector cone and re-entrant throat member comprised of a castable ceramic refractory material, rather than forming boiler tubes in the re-entry deflector cone. Moreover, the use of ceramic refractory materials in molding the deflector cone member is faster than rebuilding circulation tubes in the re-entrant throat member of the cyclone furnace and less expensive. Additionally, the heat retentive characteristics of the ceramic refractory throat member improves the operating conditions at the outlet end of the cyclone furnace. During combustion, the ceramic refractory deflector cone member absorbs and retains heat to elevate and sustain the high temperatures at the outlet end of the chamber to thereby provide a more complete burn of the fuel-air mixture as the mixture exits the cyclone furnace chamber. The increased temperature at the outlet end of the cyclone furnace results in an increase in temperature in the vicinity of the slag tap opening thereby facilitating and maintaining a liquid flow of the slag out of the cyclone furnace, a result which enhances the combustion cycle within the cyclone.
Other and additional objects of the present invention will be apparent from the following description and claims that are illustrated in the accompanying drawings which, by way of illustration, show a preferred embodiment of the present invention and the principles thereof and what is now considered to be best mode contemplated in applying these principles. Other embodiments of the present invention employing the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the scope of the appended claim.
REFERENCES:
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patent: 2971480 (1961-02-01), Sage
patent: 3124086 (1984-03-01), Sage et al.
patent: 4473014 (1984-09-01), Dejanovich
patent: 4565137 (1986-01-01), Wright
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patent: 5976445 (1999-11-01), Kuroda et al.
patent: 5979720 (1999-11-01), Nomura et al.
patent: 6031207 (2000-02-01), Dover et al.
Cyclone Combustion Enhancement Group, LLC
Emrich & -Dithmar
Ferensic Denise L.
Rinehart Ken
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