Combustion – Porous – capillary – particulate or sievelike flame holder,... – Means supplying fuel for passage through the flame holding...
Patent
1996-01-22
1998-05-12
Dority, Carroll B.
Combustion
Porous, capillary, particulate or sievelike flame holder,...
Means supplying fuel for passage through the flame holding...
F23D 1412
Patent
active
057497214
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a ceramic combustion support element, preferably in the form of a ceramic composite body in surface radiant burners for industrial conversion and heating processes in the temperature range up to in particular approximately 1300.degree. C., and a process for producing the same.
2. Description of the Related Art
Surface radiant burners in many forms are employed in particular for space heating and drying purposes in the infra-red range and as low-pollution combustion units in the heating and boiler field. Here above all, the possibility of a low-pollution operation at operating temperatures up to 1000.degree. C. are exploited.
In general, a distinction can be made between two basic types, namely multi-flame surface burners and quasi-flameless surface burners.
Multi-flame burners are distinguished in that, from the burner surface, many individual flames form which in particular performance ranges can unite into a flame front.
Inter alia, stable perforated or slitted flame support elements are employed in order to improve working life relative to metallic flame supports, such as for example described in DE-A-40 41 061, from which there can be understood a ceramic combustion support element over which the present invention is an improvement. For reasons of safety with regard to flareback, the removal of heat remains relatively small. Nitrogen oxide formation is greater than in comparable quasi-flameless surface burners. The working range is additionally restricted through a higher CO and CxHy component. This is the case also for ceramics which are porous in the manner of a conglomeration of ceramics particles bound together in a manner which forms or leaves interstices, as for example described in EP-A-0 056 757. The binders employed here, clay or bentonite, allow there to be expected a sufficient working life in cyclical operation, with the necessary flareback security, only with small temperature drops over the layer thickness of the ceramics. Additionally, with the described low pressure loss of the ceramic in the case of a cylindrical form closed at one end, a factor is an expected unevenness of the flame distribution with increased energy transport towards the closed head end.
The quasi-flameless surface burners form a second group. With this burner type, in a certain performance range, the flame roots sit in the surface layer of the combustion support and cause this to glow. Through the removal of considerable proportions of radiative heat, the combustion temperature of the fuel-air mixture lead through the flame support, and the NOx-formation, is markedly suppressed. Above a certain burner power and at high combustion air excess, with these burners also the flame detaches itself from the surface and causes a deterioration in the exhaust cleanliness. A significant form of this burner type is based on radiative combustion elements of ceramic fibers, which are deposited by means of vacuum forming together with binders preferably on a metal sieve. Configurations of this form are described for example in EP-A-0 382 674, EP-A-0 397 591; U.S. Pat. No. 4,416,619; DE-A-3 311 953; U.S. Pat. No. 3,179, 156; U.S. Pat. No. 3,275,497 and U.S. Pat. No. 4,519,770.
The flame support proposals described in EP-A-0 382 674 and EP-A-0 397 591 permit only a vary narrow control range to be expected. The thick fiber layer, bonded in accordance with the description with alumina coating, is mechanically fragile, in particular sensitive to any handling, to vibration and tends increasingly to erosion with the thermal aging process. The closed burner head form means that there is to be expected a build-up effect with uneven distribution of flames on the ceramic coating and therewith a deterioration of the exhaust cleanliness and increased erosion of fibers in this region (hot-spot formation).
In general, the binder structure with the desired gamma and theta phases of Al.sub.2 O.sub.3 as main binder component, as described in U.S. Pat. No. 4,416,619 and D
REFERENCES:
patent: 1830826 (1931-11-01), Cox
patent: 3179156 (1965-04-01), Weiss et al.
patent: 3208247 (1965-09-01), Weil et al.
patent: 3275497 (1966-09-01), Weill et al.
patent: 3322179 (1967-05-01), Goodell
patent: 3912443 (1975-10-01), Ravault et al.
patent: 4039480 (1977-08-01), Watson et al.
patent: 4189294 (1980-02-01), Rice et al.
patent: 4416619 (1983-11-01), Craig et al.
patent: 4519770 (1985-05-01), Kesselring et al.
patent: 4533318 (1985-08-01), Buehl
patent: 4599066 (1986-07-01), Granberg
patent: 4605369 (1986-08-01), Buehl
patent: 4643667 (1987-02-01), Fleming
patent: 4673349 (1987-06-01), Abe et al.
patent: 4721456 (1988-01-01), Granberg et al.
patent: 4814300 (1989-03-01), Helferich
patent: 4889481 (1989-12-01), Morris et al.
patent: 5249953 (1993-10-01), Roth et al.
patent: 5356487 (1994-10-01), Goldstein et al.
Birnkraut Ingo
Gutknecht Michael
Klinge Bernd
Weise Bernd
Dority Carroll B.
Gossler Thermal Ceramics GMBH
LandOfFree
Ceramic combustion support element for surface burners and proce does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ceramic combustion support element for surface burners and proce, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ceramic combustion support element for surface burners and proce will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-974743