Power plants – Combustion products used as motive fluid
Patent
1997-12-08
1999-11-23
Kim, Ted
Power plants
Combustion products used as motive fluid
60 3912, 60 39182, F02B 4300, F02C 600, F01K 2306
Patent
active
059878746
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/SE96/00654 filed May 20, 1996.
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for power generation based on char.
DESCRIPTION OF THE RELATED ART
In recent years a number of systems have been suggested for power generation based on sub-bituminous and bituminous coals according to which the coal is combusted in two steps: a first partial combustion step with an understoichiometric air ratio and a final combustion step with excess air. Both steps work with overpressure and with gases being produced. Low Btu gas from the first step and flue gases from the second are utilized in a combined cycle with gas as well as a steam turbine. Such a system is described in the conference notes from the EPRI Conference on Fluidized Bed Combustion for Power Generation, Atlanta, May 17-19, 1994 titled "PFBC Perspectives at the Power Systems Development Facility".
In that system there is described the use of raw material, e.g., coal of all types, in dry powdered state being fed into a pressurized carbonizer, where about 70% of the coal is combusted with air (partial combustion) in a fluidized bed at about 925.degree. C. in presence of a sulphur sorbent and is transformed to low Btu gas and char. The latter is combusted with excess air in a pressurized circulating fluidized bed ("PCFBC") at about 850.degree. C. in the presence of sulphur sorbent. Produced flue gas, after dust cleaning, is fed to the combustor of a gas turbine, in which the temperature of the gas is increased by combustion in mixture with the low Btu gas from the carbonizer "topping". After power generation in the gas turbine, the heat content of the flue gases is utilized in a steam generator for production of steam. The steam is utilized for power generation in a steam turbine. The temperature in the PCFBC must be controlled within a rather narrow interval to bring about effective sulphur fixation to the sorbent, which is accomplished by built-in heat exchangers, working as once through steam generators, in the bed material circulation cycle of the PCFBC.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an improved power generation system and method utilizing a system with devices for power generation based on char, preferably char from a pyrogas generator according to patent SE-9200989-3. The invention is described below in more detail in a manner which will be appreciated by one of skill in the art.
The system according to the invention works in a combined cycle with steam and gas turbines and suitably at a pressure, which by a few bar exceeds the admission pressure of the system's gas turbine. Further, the invention provides a combination of seven operations which follow.
1. Partial combustion of char in a first step at 750-850.degree. C. with greater than 500.degree. C., preferably about 600.degree. C., preheated air in a bubbling spouting fluidized bed in the presence of a flow of bed material (char ash and reaction products of the sorbent), the flow of bed material being greater than 20 times the flow of char.
2. Final combustion in a second step at about 850.degree. C. and with a large excess of air suitably corresponding to greater than three times the theoretical air ratio for complete combustion, of the first step formed carbon monoxide and unburned char, greater than 500.degree. C., preferably about 600.degree. C. preheated air is provided in the presence of a flow of bed material greater than 40 times the flow of the char.
3. Separation in a gas cleaning unit at high temperature of bed material and gas in the suspension from the final combustion step and delivering: the separated material to an intermediate multi-function container, and the cleaned gas to the gas turbine of the system.
4. Recirculation of bed material from the gas cleaning unit via the intermediate container to the combustion steps, where an adapted utilization of the heat content of the bed material by heat exchanging and splitting of the bed material flow into two partial flows
REFERENCES:
patent: 4338788 (1982-07-01), Fink
patent: 4508041 (1985-04-01), Voetter et al.
patent: 4655147 (1987-04-01), Brannstrom et al.
patent: 5099801 (1992-03-01), Scholl et al.
patent: 5241825 (1993-09-01), Collin et al.
patent: 5255507 (1993-10-01), Gounder
patent: 5327726 (1994-07-01), Daman et al.
patent: 5469698 (1995-11-01), Garcia-Mallol et al.
patent: 5765365 (1998-06-01), Fujioka et al.
Kim Ted
Nykomb Synergetics Technology Holding AB
LandOfFree
Method and apparatus for power generation based on char and a fl 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 apparatus for power generation based on char and a fl, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for power generation based on char and a fl will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1208005