Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
  • F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
  • F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
  • F01K23/06—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle
  • F01K23/10—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle with exhaust fluid of one cycle heating the fluid in another cycle

Definitions

• the invention relates to a method for the environmentally compatible generation of energy in a combined gas-steam power plant by work-relieving relaxation of a high-tension hot working medium in a gas turbine and of high-tension superheated steam in a steam turbine, the residual heat of the relaxed working medium of the gas turbine Generation of water vapor is used, as well as a plant for performing such a method.
• the accumulating in the oil or gas fired combustor of the gas turbine compressed working gas at a Tempe ⁇ is first work-expanded temperature of now more than 1,000 * C in the gas turbine and then further cooled in a waste heat boiler to produce high-pressure steam.
• the cooled flue gas is released into the atmosphere via a chimney.
• the steam generated is expanded in a steam turbine.
• the steam temperatures and thus the working capacity of the steam turbine are disadvantageously predetermined or limited by the, in some cases, relatively low exhaust gas temperatures of the gas turbine.
• the invention is therefore based on the object of a method of the type mentioned at the outset for generating energy in a combined gas-steam turbine process both for achieving higher outputs and thus for reducing the specific CO2 emissions and also for reducing the nitrogen oxide ⁇ to further develop emissions.
• This object is achieved in that the water vapor is additionally overheated before it relaxes in the furnace of a fluidized bed furnace.
• the performance of the turbine is increased considerably. For example, performs a Tempe ⁇ raturerhöhung the highly strained water vapor from 500 * C to 600 * C already an increase in the turbine power by more than 5%. It proves particularly advantageous that the temperature increase of the water vapor takes place in a fluidized bed furnace, since such furnaces are characterized by particularly good heat transfers from the fluidizing bed material to the heat exchanger surfaces immersed in the bed. As a result of the relatively low and, above all, very uniform temperatures distributed over the cross section of the bed there are also no material problems with regard to the heat exchanger tubes through which the high pressure steam flows. Due to the low bed temperatures, the formation of thermal nitrogen oxides is also not very pronounced in fluidized bed firing.
• the fluidized bed combustion can be operated both with oil or gas and with a solid fuel, with in the case of oil or gas firing a suitable foreign material, such as e.g. Quartz sand, to be provided as bed material, while the ashes are used as bed material in the combustion of coal.
• a suitable foreign material such as e.g. Quartz sand
• the nitrogen oxide formation in the combustion chamber of the gas turbine can also be considerably reduced if, according to a further feature of the invention, part of the working medium of the gas turbine, which is relaxed and cooled during work, that is to say the low-oxygen gas turbine exhaust gas, is mixed with and mixed with the fresh air to be compressed is fed back into the combustion chamber of the gas turbine.
• This measure replaces the part of the fresh air, which was essentially only provided as a mass flow for the gas turbine in a method according to the prior art, with the oxygen-poor exhaust gas from the gas turbine, so that the combustion in the combustion chamber with far less excess oxygen can be done. This in turn has the consequence that almost no thermal nitrogen oxides are generated in the combustion chamber of the gas turbine.
• the remainder of the non-recycled gas turbine gas which still has a temperature of approximately 80 ° C., is expediently mixed with the flue gas from the fluidized bed furnace and released together with the latter into the atmosphere via a suitable chimney.
• the invention provides for the integration of a further self-heated steam generator, in which case the flue gases from the fluidized bed furnace are then introduced directly into the furnace of the further steam generator.
• the residual heat of the flue gas from the fluidized bed furnace can be directly used in the further steam generator.
• the nitrogen oxide content in the total smoke gas stream of the further steam generator can be influenced favorably.
• the temperature and thus the working capacity of the superheated high-pressure steam obtained in the further steam generator can be increased if it is mixed with the very hot water vapor from the fluidized bed combustion in a suitable mixing collector before it is released , and both steam flows are then fed to the same steam turbine.
• a combined gas-steam power plant for carrying out the method according to the invention has a gas turbine, a waste heat boiler downstream of the gas turbine for steam generation and a steam turbine and is characterized by a fluidized bed combustion with a heat exchanger arranged in the combustion chamber, the cold end of which connects to the steam outlet of the heat exchanger and its warm end mi * ; - is connected to the steam inlet of the steam turbine.
• the nitrogen oxide content is also relatively low in the total smoke gas flow to be released into the atmosphere, so that - depending on the required limit values - only correspondingly reduced measures or no measures at all are required for subsequent denitrification of the smoke gases.
• the formation of CO2 is reduced accordingly.
• the application of the invention also lends itself particularly to the retrofitting of existing power plants.
• the proposed measures such as connecting upstream and connecting a gas turbine and fluidized bed combustion to the existing steam generator and moving a part, can now be implemented the heat output of the steam generator on the upstream furnaces.
• the investment costs for the proposals according to the invention are comparable at least in the order of magnitude with the costs for subsequent denitrification measures, it follows that at least the energy gain resulting from the increase in efficiency is made available practically free of charge.
• the invention in connection with the retrofitting of old power plants, but also in the construction of new power plants, the invention with the same advantages can be used both in coal dust furnaces with dry ash removal and in furnaces with liquid ash extraction.
• Figure 1 shows an embodiment of a combined steam power plant in the range of small to medium power
• Figure 2 shows an embodiment in connection with the Um-. or retrofitting an existing coal-fired power plant.
• fresh air for the gas turbine cycle is fed to the system via a line 1, compressed to about 6-20 bar in a compressor 2 and then introduced as combustion air into a gas or oil-fired combustion chamber 3.
• the hot working gas produced in the combustion chamber 3 is expanded to about 1 bar in a gas turbine 4, which is seated on a shaft with a generator 5 and the compressor 2.
• the inlet temperature of the gas turbine 4 is approximately 800 - 1,300 * C and the outlet temperature is approximately 400 - 600 * C.
• the residual heat of at 400-600 * C accumulating exhaust gas of the Gas ⁇ turbine 4 is used in a waste heat boiler 6 for generating steam for the steam turbine process.
• This high-tension (approximately 20-300 bar) water vapor occurring in the waste heat boiler 6 at a temperature of approximately 300-500 ° C. is now, according to the invention, in a heat exchanger 7 which is arranged in the fluidized bed of a fluidized bed furnace 8 with a fuel supply 9, to a temperature of about 540-600 * C, and then further heated in a relaxed connected to a generator 10 steam turbine.
• the processed steam is liquefied in a condenser 12, pressurized again in a feed water pump 13 and returned to the waste heat boiler 6 via a line 23 in the circuit. It has been shown that the performance of the steam turbine 11 can be increased considerably by the further overheating of the water vapor in the fluidized bed furnace 8.
• the flue gas of the fluidized bed system 8 fired with coal in the present example is cooled in a heat exchanger 14 against fresh air, dedusted in an electrostatic filter 15, in one.
• System 16 desulfurized and then withdrawn via a line 17.
• a suction fan 24 serves to compensate for the pressure losses.
• the fresh air required for the fluidized bed combustion 8 is supplied via a line 18, an induced draft fan 19 and a pressure increasing fan 25.
• a considerable reduction in nitrogen oxide formation can also be achieved if a partial stream of the gas turbine exhaust gas is continuously mixed with the fresh air via a line 20 and together with this in the combustion chamber 3 is returned.
• the amount of the recirculated exhaust gas partial flow is measured according to the mass flow required for optimal performance of the gas turbine 4 and can be up to 50% of the total exhaust gas amount.
• part of the flue gas from the fluidized bed furnace 8 can also be returned to the furnace via a line 21, the fluidized bed Firing (8) is known, however, already characterized by a low nitrogen oxide formation.
• the virtually non-nitrogen oxide-free residual stream of the gas turbine exhaust gas which is not returned to the combustion chamber 3 is fed via a line. 22 deducted, mixed with the flue gas stream flowing via line 17 and released into the atmosphere via a chimney or a cooling tower, not shown here. Additional measures for denitrification are generally not necessary to achieve the required limit values.
• the power plant to be retrofitted consists of a steam generator 30 with a dry-ash buried fire chamber 31, a fuel supply 32 and heating surfaces 33, 34 for generating the high-pressure steam in the water-steam cycle, which in addition to the heating surfaces 33, 34 is a steam turbine 35 as further main components having a generator 36, a steam condenser 37 and a feed water pump 38.
• the flue gas from the steam generator 30 successively passes through an air preheater 39, an electrostatic filter 40, a suction fan 41, a desulfurization system 42 and is then fed via line 43 to a chimney (not shown) or a cooling tower (also not shown) for discharge into the atmosphere .
• the required fresh air is drawn in via a fresh air blower 44, preheated in the heat exchangers 45 and 39 and then fed into the combustion chamber 31.
• the coupling takes place, inter alia, in that the still hot, low nitrogen oxide flue gases of the fluidized bed system 8 are introduced directly into the combustion chamber 31 of the steam generator 30, whereby on the one hand the residual heat of the flue gases is emitted directly to the water-steam circuit 33, 34 of the steam generator 30 can and on the other hand the existing devices for flue gas cooling and purification can also be used for the treatment of the flue gases of the fluidized bed furnace 8.
• the high pressure steam of the steam generator 30 is mixed with the strongly superheated water vapor from the fluidized bed system 8 in a mixing collector 46 after it has been relaxed in the steam turbine 35.
• the resulting mixing temperature is above the maximum temperature achievable in the steam generator 30, so that the steam turbine 35 has a higher inlet temperature with a corresponding increase in output.
• the flue gas streams from the combustion chamber 3 and the fluidized bed furnace 8 being almost the result of the proposed measures are nitrogen oxide-free, with a corresponding optimization, in particular in old plants with dry ash removal, a final nitrogen oxide concentration can generally be set which satisfies the respectively required limit values.
• the integration of a gas turbine cycle and the additional superheating of the water vapor in the mixing collector 46 can improve the efficiency of the power plant> 45% with a corresponding reduction in the specific CO2 emissions.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Engine Equipment That Uses Special Cycles (AREA)

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• 1991
  • 1991-05-25 DE DE19914117192 patent/DE4117192C2/de not_active Expired - Fee Related
• 1992
  • 1992-05-21 JP JP4509146A patent/JPH06511060A/ja active Pending
  • 1992-05-21 WO PCT/DE1992/000412 patent/WO1992021858A1/de not_active Application Discontinuation
  • 1992-05-21 AU AU16918/92A patent/AU1691892A/en not_active Abandoned
  • 1992-05-21 EP EP19920910239 patent/EP0586431A1/de not_active Withdrawn
  • 1992-05-21 CA CA002109963A patent/CA2109963A1/en not_active Abandoned

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