Furnaces – Refuse incinerator – Refuse suspended in or supported by a fluid medium
Patent
1985-07-03
1987-03-10
Yuen, Henry C.
Furnaces
Refuse incinerator
Refuse suspended in or supported by a fluid medium
110346, 110267, 110270, F23G 500
Patent
active
046483292
DESCRIPTION:
BRIEF SUMMARY
The present invention concerns a device for reinjecting flown-off particles during combustion in the fire box of a solid fuel boiler or furnace of the so-called "projector with back grid" type.
Such a boiler is characterised by the fact that it is fed with fuel, for example coal having a granulometry able to reach several tens of millimeters, or wood, husks, bagasse, or other comparable combustible solids, by fuel feed means arranged adjacent a first zone of the boiler and which project continuously a determined load of fuel along a trajectory leading to a second zone of the boiler, onto a grid driven with a return movement from this second zone towards the first; combustion taking place during the course of the said trajectory and continuing not only during the end of it but also on the grid, where this combustion ends so that the grid drives only ashes into the first zone, whence these ashes are evacuated.
Boilers of this type have a certain number of advantages.
With respect to boilers with a mechanical grid, in which the combustion occurs exclusively on the grid, they have advantages connected with the fact that a part of the combustion occurs during the projection of the fuel, that is on the one hand an increase in the rate of combustion with the resultant possibility of reduction of the surface of the grid, and on the other hand a consequent flexibility of operation, permitting rapid changes of load to be made in the best conditions.
With respect to pulverised coal boilers, boilers of this type have the advantage of using coals of varied granulometry, and in particular coals of a greater granulometry which does away with crushing means, which are necessary for pulverised coal boilers and are costly in terms of investment, maintenance and consumption of energy.
Nevertheless, the development of boilers with a projector and a back grid has been limited until now, by reason of a lower output than that of other types of boilers, and more precisely because of the very important rate of combustible particles unburned.
In fact, the feed of fuel by projection permits the flying off, with the flue gases released by the combustion, of sufficiently light combustible particles to be thus entrained but nevertheless too heavy to burn completely in the course of the trajectory. This inconvenience is marked with respect to fixed grid boilers, where there is no projection, and with respect to pulverised coal boilers, which use coal of a sufficiently fine granulometry that the rate of unburned particles is minimal. In comparison with other types of boilers, an increase in the proportion of solid particles extracted from the flue gases, before evacuation to the atmosphere, by appropriate dust removers, with a greater proportion of carbon in the particles is noticed in the use of boilers with a projector and back grid. In other terms, an increase of losses and unburned solids is noted. In addition, the evacuation of solid particles extracted from the flue gases by the dust removers can present difficulties on account of their number.
For remedying these inconveniences of projector and back grid boilers, it has been proposed to reinject into the boiler a part of the solid particles flown off with the flue gases, after they have been caught at the outlet from the boiler by means of dust removers or separators used for purifying these flue gases before their being ejected into the atmosphere.
In practice, such dust removers or separators are normally provided in series, for extracting from the flue gasses first the larger particles and then the finer particles. Up to now the larger particles separated first have been reinjected, but the finer particles have not also been rejected, since the fine particles are particularly difficult to burn before they fly off again, carried by the flue gasses. In other terms, up to now one has been limited to a reinjection of the larger particles insofar as there exists a significant risk that the reinjection of the finer particles will lead immediately to their flying off again, with or wi
REFERENCES:
patent: 4259911 (1981-04-01), Jones
patent: 4263857 (1981-04-01), Ban
patent: 4279222 (1981-07-01), Pearce
patent: 4355601 (1982-10-01), Hattiangadi
patent: 4416418 (1983-11-01), Goodstine et al.
patent: 4419940 (1983-12-01), Cosan et al.
patent: 4434724 (1984-03-01), Kunkel, Jr.
patent: 4446799 (1984-05-01), Anderson
patent: 4474119 (1984-10-01), Jones
patent: 4532872 (1985-08-01), Anderson
patent: 4552097 (1985-11-01), Jarmuzewski
Bernet Robert R. E.
Bessouat Roger
Couarc'h Michel F. E.
Lafaye Marc R. R.
Manutair Moller
Stein Industrie
Yuen Henry C.
LandOfFree
Device for reinjecting flown-off particles into a solid fuel boi does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for reinjecting flown-off particles into a solid fuel boi, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for reinjecting flown-off particles into a solid fuel boi will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1015925