Power plants – Combustion products used as motive fluid
Patent
1993-01-08
1994-05-31
Casaregola, Louis J.
Power plants
Combustion products used as motive fluid
60 39464, 60728, F02C 326
Patent
active
053158164
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to limitation of temperature variations in flowing gases in a combustion plant in which heat transfer surfaces are arranged in the gas paths to limit the temperature of the gas which is supplied to a combustor located in the plant and of the flue gases emitted from the plant. The invention is especially valuable in a power plant with combustion in a pressurized fluidized bed, a Pressurized Fluidized Bed Combustion (PFBC)--plant, in which it permits limitation of temperature variations in pressurized air supplied to the combustor and flue gases emitted from the plant. This means that power output or efficiency remains essentially unaffected by variations in ambient temperature and compression ratios.
BACKGROUND OF THE INVENTION
During combustion in a fluidized bed, the fluidized bed is supplied with air for fluidization of the bed material and for combustion of fuel supplied to the fluidized bed. If the fluidized bed is part of a plant for combustion in a pressurized fluidized bed, a PFBC plant, the fluidized bed contained within a bed vessel is enclosed in a pressure vessel and the air supplied to the fluidized bed is pressurized, for example in a compressor driven by a gas turbine.
The mass flow of pressurized air supplied to a PFBC plant is controlled within an interval of 40-105% of nominal flow. The pressurization is normally carried out in a gas turbine-driven compressor. From the point of view of capital cost, high compression ratios are desirable A gas turbine-driven compressor provides different possibilities of controlling the mass flow, depending on the type of gas turbine. A single-shaft unit may control the mass flow by varying the adjustment of compressor guide vanes and inlet valves, and, in addition, compressed air may be recirculated through the compressor. Moreover, in a multi-shaft unit, adjustable turbine guide vanes and nozzles as well as variable rotor speed are utilized.
The temperature of the air supplied from the compressor via the pressure vessel to the fluidized bed must be limited, both when the air is used for cooling of pressure vessel, bed vessel, cyclones and other supporting components arranged in the pressure vessel, and when temperature variations, caused by compression ratios and ambient temperature, in air supplied to the fluidized bed affect the output power from the plant and the efficiency of the plant.
The temperature of air supplied to the pressure vessel is not limited in normal PFBC plants, and thus there is no equalization of the temperature variations which occur in the pressurized air. Temperature variations occur as a consequence of variations in the ambient temperature and varying compression ratios and are compensated for in a normal PFBC plant by a change in the output power from the plant and in the efficiency of the plant.
The residual heat in flue gases emitted from a combustion plant is delivered to flue gas economizers, which are arranged in the flue gas paths.
SUMMARY OF THE INVENTION
The influence of variations in the ambient temperature, compression ratios in air pressurized in the compressor, and the like, which in a plant for combustion in a pressurized fluidized bed, a PFBC--plant, is reflected in the output power from the plant and in the efficiency of the plant, is essentially eliminated when temperature variations in incoming Combustion air are limited according to the present invention.
The plant comprises a combustor in the form of a pressurized fluidized bed, air paths in which air supplied to the fluidized bed is pressurized, flue gas paths in which energy contained in flue gases emitted from the plant is partially extracted with a gas turbine arranged in the flue gas paths, and a feedwater/steam system comprising heat transfer surfaces arranged in the air and flue gas paths.
According to the present invention, the temperature variations of pressurized air supplied to the fluidized bed are limited by means of heat transfer surfaces, preferably in the form of a heat exchanger, arranged in
REFERENCES:
patent: 3422800 (1969-01-01), LaHaye
patent: 4852345 (1989-08-01), Greis
patent: 4852346 (1989-08-01), Granqvist et al.
patent: 4951460 (1990-08-01), Prochaska et al.
patent: 5010726 (1991-04-01), Garland
Kemmer Leif
Mukherjee Dilip
Tjellander Goran
ABB Stal AB
Casaregola Louis J.
LandOfFree
Method and device for temperature control in a combustion plant 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 and device for temperature control in a combustion plant, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and device for temperature control in a combustion plant will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1620225