Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
  • F02C3/00—Gas-turbine plants characterised by the use of combustion products as the working fluid
  • F02C3/20—Gas-turbine plants characterised by the use of combustion products as the working fluid using a special fuel, oxidant, or dilution fluid to generate the combustion products
  • F02C3/205—Gas-turbine plants characterised by the use of combustion products as the working fluid using a special fuel, oxidant, or dilution fluid to generate the combustion products in a fluidised-bed combustor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
  • F02C3/00—Gas-turbine plants characterised by the use of combustion products as the working fluid
  • F02C3/20—Gas-turbine plants characterised by the use of combustion products as the working fluid using a special fuel, oxidant, or dilution fluid to generate the combustion products
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
  • F02C3/00—Gas-turbine plants characterised by the use of combustion products as the working fluid
  • F02C3/20—Gas-turbine plants characterised by the use of combustion products as the working fluid using a special fuel, oxidant, or dilution fluid to generate the combustion products
  • F02C3/26—Gas-turbine plants characterised by the use of combustion products as the working fluid using a special fuel, oxidant, or dilution fluid to generate the combustion products the fuel or oxidant being solid or pulverulent, e.g. in slurry or suspension
  • F02C3/28—Gas-turbine plants characterised by the use of combustion products as the working fluid using a special fuel, oxidant, or dilution fluid to generate the combustion products the fuel or oxidant being solid or pulverulent, e.g. in slurry or suspension using a separate gas producer for gasifying the fuel before combustion

Definitions

• the present invention relates to a power plant com- prising a combustor, in which a combustion of a fuel while forming hot flue gases is intended to take place, means for supply of first combustible gases to a location in or in the immediate proximity of a path of said flue gases downstream of the combustor and at least a burner arranged to cause a combustion of said first combustible gases at said location for mixing the gases resulting therefrom with said flue gases for increasing the temperature of the latters .
• the supply of the combustible gases to and the com ⁇ bustion thereof in or in the proximity of the flue gas path takes in such a power plant primarily place for increasing the temperature of the flue gases so as to make it possible to increase the efficiency of the power plant or simply increase the possible power output therefrom.
• All conceivable types of power plants in which flue gases are formed during combus ⁇ tion of a fuel may be concerned, such as power plants having fluidised beds of for example bubbling or cir- culating type for combustion of particle-like fuel, oil-fired boilers, soda pans and ⁇ o or.
• power plant is m this disclosure de ⁇ fined as comprising not only plants for generating electricity but also all types of plants for generat- ing heat or heat and electricity.
• PFBC-power plant i.e. a plant for combustion of particle-like fuel in a pres ⁇ surised fluidised bed, will hereinafter be described.
• a power plant of this type i ⁇ already known through for example SE publication 458 955 and the Swedish patent application 9501097-1 of the applicant, in which the combustible gases are supplied to the top ⁇ ping combustor, in which they are combusted and the hot gases resulting therefrom are mixed with the flue gases for increasing the temperature thereof before they reach the gas turbine belonging to the power plant.
• the chemistry of the fuel bed in said combustor makes it impossible to ob ⁇ tain flue gases having a higher temperature than about 950°C in such a power plant, but the power that may be generated by the gas turbine rises very strongly with a temperature of the propellant gas, i. e. the flue gases, increased therebeyond, which makes it desirable to increase the temperature thereof to 1200-1500°C, so that a higher total effi ⁇ ciency of the plant is obtained.
• the object of the present invention is to find a rem ⁇ edy to the inconveniences mentioned above of prior art power plants of the type defined m the introduc ⁇ tion by providing a power plant having an increased flexibility with respect to adaption to the power output required therefrom and primarily having an m creased ability to rapidly be adapted to an increased power output required.
• This object is according to the invention obtained by providing such a power plant with additional means separated from said means for supplying additional second combustible gases to said location, and said additional means comprises members for optionally regulating the supply of said additional second com- bustible gases It will m this way be possible to obtain a very fast load increase when it is suddenly called for a load increase from the partial load op ⁇ eration, since said members may be regulated to sup ⁇ ply said additional second combustible gases to said location, so that the gas flow to a gas turbine, if the plant has such one, may directly be increased and the power increase upon load increase may be acceler ⁇ ated.
• the additional combustion at said lo ⁇ cation a power addition is obtained, which in the case of a power plant having a gas turbine is given to the gas turbine, which by that may generate more air and power quicker.
• said members are adapted to keep the ⁇ upply of the second combustible gases closed at normal operation of the power plant at substantially constant power output therefrom
• said second combustible gases will by that only be utilised when the power output of the power plant is to be changed, and it is then of course a question of an increase of this power output, and such an increase may then be realised more rapidly through the possibility to supply the second combustible gases to said location for m- creasing the flue gas flow from said location and possibly the temperature thereof .
• the power plant comprises a means for provid- mg said first combustible gases, th s means is adapted to also provide the second combustible gases and it is adapted to provide the gases b/ gasifying a liquid or solid fuel
• th s means is adapted to also provide the second combustible gases and it is adapted to provide the gases b/ gasifying a liquid or solid fuel
• the power plant comprises a container for storing the second combustible gases and this is con ⁇ nected to said locations through a connection which may be optionally opened.
• a container for storing the second com ⁇ bustible gases in this way in a container they may instantaneously be supplied to said location through opening the connection.
• the gasifier may charge the con ⁇ tainer, when it i ⁇ able to gasify more fuel than is presently desired to supply to ⁇ aid location, and these second combustible gases may than be supplied to said location when the gasifier is not able to produce the amount combustible gases that would be desired to then supply to the location, i.e. primar- ily when there is a desire of a rapid load rise of the power plant .
• Another preferred embodiment of the invention is directed to exactly this possibility and it relates to a power plant comprising means adapted to accomplish charging of the container with ⁇ econd combustible gases when the supply of said additional second combustible gases to said location i ⁇ closed.
• the charging of the container takes place at a time when no supply of the second combustible gases to said location is required.
• the power plant comprises members for con ⁇ trolling said means for supplying the second combus ⁇ tible gases for supply thereof to ⁇ aid location when an increase of the power desired to be tapped from the power plant occurs . It will by that be pos ⁇ ible to ensure a very rapid such a power increase for the reasons discussed further above .
• the power plant comprise ⁇ a gas turbine in ⁇ tended to be driven by said flue gases
• the problem according to invention is particularly accentuated in the case of a power plant of the type defined m the introduction having such a ga ⁇ turbine and the advan tages of supplying said second combustible gases are particularly great m such a case, although the prob ⁇ lem according to the invention is not at all only ap ⁇ plicable to power plants having a gas turbine
• the power plant comprises at least a room, m which combustion of said first and second combus- tible gases and a mixing of the gases resulting therefrom with said flue gases for temperature in ⁇ crease thereof is intended to take place, and said room is arranged m the path of the flue gases down ⁇ stream of the combustor.
• Such a room may according to another preferred embodiment of the invention be a so called topping combustor, which is arranged m he path of the flue gases upstream of the gas turbine, and it may according to yet another preferred embodi ⁇ ment of the invention be a ⁇ o called reheating co - bustor or a reheating combustion chamber, which m the case of at least two gas turbines of the power plant is arranged in the path of the flue gases be ⁇ tween the two gas turbines so as to increase the tem ⁇ perature of the flue gases which have experienced a temperature reduction in the first gas turbine, be ⁇ fore they are supplied to the gas turbine following thereupon, so that the power of the gas turbine may be rapidly increased by the supply of the second com ⁇ bustible gases to the flue gases and it is effi- ciently contributed to a fast load increase of the power plant .
• said means for supplying said additional second combustible gases is adapted to supply the ⁇ e both to a ⁇ o called topping combustor and a so called reheating combustor for providing a possibility to a very fast load rise of such a power plant.
• FIG. 1 illustrates schematically a PFBC- power plant having a combined gas and steam cycle (the latter is not shown) according to a preferred embodiment of the invention.
• the invention is as already mentioned not in any way restricted to the application to a PFBC-power plant, i.e. a plant for combustion of particle-like fuel in a pressurised fluidised bed, but it will nevertheless hereinafter be described as applied to such a plant for explaining the basic idea of the invention, since the problem upon which the invention is based is par ⁇ ticularly pronounced for thi ⁇ type of power plant .
• a PFBC-power plant i.e. a plant for combustion of particle-like fuel in a pressurised fluidised bed
• a vessel 2 which may have a volume in the order of 10 4 m 3 and which may be pres ⁇ surised to for example about 16 bars .
• Compressed air 3 for pres ⁇ urising the combustor 1 and for fluidising a bed 4 in the combustor is supplied to the pressure vessel.
• the compressed air is applied to the combus- tor through fluidising nozzles 5 schematically indi ⁇ cated at the bottom of the combustor for fluidising the bed enclosed in the combustor.
• the bed consists of bed material, granule-shaped absorbent and a par ⁇ ticle-like fuel, preferably crushed carbon, which is combusted in the fluidising air led to the bed.
• the combustion gases hereinafter called flue gases, from the bed are then led through a purification apparatus 6, which in the example con ⁇ i ⁇ t ⁇ of a high tempera ⁇ ture filter intended for high pressures, and an in- tercept valve 7 to a fir ⁇ t room 8 in the form of a topping combustor.
• the combustible gas is al ⁇ o sup ⁇ plied to the topping combustor 8 through a conduit 9 from a gasifier 10 of known type to a high tempera ⁇ ture filter 11, a nonreturn valve 12 and a member 13, a valve, for optional regulation of the flov; in the conduit 9.
• the combustible gases are combusted in the topping combustor 8, and these are here called first combustible gases, in connection with supply of com ⁇ pressed air through the conduit 14 from a high pres- sure compressor 15 through influence of a burner 42 and mixed with the flue gases from the combustor 1 for increasing the temperature thereof, so that the gases leaving the topping combustor have a tempera ⁇ ture (1200-1500°C) making them well suited a ⁇ propel- lant ga ⁇ for propelling a fir ⁇ t turbine 16 in the form of a high pressure turbine.
• the temperature of said combustion gases has through the topping combus ⁇ tor been increased from about 850-950°C to 1200- 1500°C.
• the high pressure turbine and the high pressure com ⁇ pressor are arranged on the same axle as a generator 17, from which usable energy may be taken.
• the high pres ⁇ ure compressor 15 delivers also compre ⁇ sed air to the PFBC-combustor 1 through the conduit 18, from which the conduit 14 is branched.
• An intercept valve 19 is arranged between the high pressure compressor and the combustor 1.
• a liquid or solid fuel, in this example particle-like carbon, which in a known way produces combustible gases dur ⁇ ing an under-stoichiometric process is gasified in the gasifier. Remaining fuel from the gasifier 10 may be supplied to the bed 4 in the combustor 1 through a fuel conduit 22.
• the PFBC-power plant shown in the figure is of an ad- vanced type, since it has a further gas turbine 23 in the form of an intermediate pressure turbine, which i ⁇ arranged on the same axle 39 as the high pressure turbine 16.
• the gas, which has been expanded and the temperature of which has been reduced in the high pre ⁇ sure turbine 16, is led through a conduit 24 to a second room 25, which i ⁇ called a reheating combustor or reheating combustion chamber.
• the reheating com ⁇ bustor 25 receives a flow of said first combustible gases deriving from the gasifier 10 and compressed air from the high pressure compressor 15 in the same way as the topping combustor 8, which is ⁇ hown in the drawing through the conduits 26 and 27, respectively, whereby these combustible ga ⁇ e ⁇ are combusted there ⁇ through a burner 43 and the hot gases so produced are mixed with the flue gases from the high pres ⁇ ure turbine, for increasing the temperature thereof again before they are supplied to the intermediate pre ⁇ ure turbine 23 through the conduit 28.
• the power taken from the intermediate pre ⁇ sure turbine may in this way be increased considerably.
• the flue gases expanded in the intermediate pressure turbine 23 are led to a low pressure turbine 29.
• the exhau ⁇ t gases leaving the low pressure turbine still contain energy, which an economiser 30 may take care of.
• a low pressure compressor 31 is also arranged on the axle 40 of the low pressure turbine 29 and atmos ⁇ pheric air is supplied thereto through a filter 32.
• the low pressure compressor is driven by the low pressure turbine and provides from the outlet thereof the high pressure compressor 15 with air com ⁇ pressed in a first step.
• An intercooler 33 is ar ⁇ ranged between the low pres ⁇ ure compressor and the high pressure compressor for lowering the temperature of the air supplied to the inlet of the high pressure compressor 15.
• the power plant has also a steam turbine side, which is not shown here but indicated through a set of tubes 38 immersed into the fluidised bed 4, in which water is circulated and evaporated and superheated through heat exchange between the tubes and the bed material for absorbing heat generating at the combus ⁇ tion taking place in the bed.
• the power plant comprises a container or accumulator tank 34 for storing combustible gases.
• the accumula- tor tank 34 is connected to the conduit 36 through a clo ⁇ eable valve member 35, through which conduit the ga ⁇ ifier 10 provides the topping combustor and the reheating combustor with combustible gase ⁇ . Further ⁇ more, the conduit 26 from the conduit 36 to the re- heating combustor is provided with a closeable valve member 37.
• the valve member 35 is preferable at maxi ⁇ mum load, i.e.
• the valve member 35 At normal op ⁇ eration of the power plant at substantially constant power output therefrom, it is intended to have the valve member 35 closed except for said charging of the accumulator tank 34, while the two valve members 13 and 37 are kept open for supply of said first com ⁇ bustible gases from the gasifier 10 to the topping combustor 8 and the reheating combustor 25, respec ⁇ tively.
• the distribution of the flow of the combusti ⁇ ble gase ⁇ to the two chambers 8 and 25 may be regu- lated by regulating the throttle degree of the ⁇ e mem ⁇ bers 13, 37. It i ⁇ of cour ⁇ e also po ⁇ ible to com ⁇ pletely close any of these valves, although it would hardly happen.
• the plant has a means 41, preferably an electrical heater, for keeping the con- tainer hot, more exactly at a temperature of 800- 1000°C, for ensuring that the second combustible gas not condenses .
• the vessel 2 and by that the combustor 1 and the flue gas paths are at partial load operation of the power plant pressurised through the compressors 31 and 15 to a lower level than at maximum load operation.
• a partial load operation suddenly a desire of an increased power output from the power plant, i.e. increasing the load thereof, arises, pos ⁇ ibly to maximum load operation, it i ⁇ of vital importance for the ⁇ peed by which the load increa ⁇ e may be accom ⁇ plished how rapidly the pressure in the system may be increased.
• the power of the gas turbine has to be m- creased for increasing the air flow from the compres- sor, which ha ⁇ m prior art power plants resulted m an initial reduction of the number of revolutions of the gas turbine and by that of the air pres ⁇ ure com ⁇ pressor, so that there will be a delay of the pres- sure increase in the system, wherein then also the pressure m the gas flow from the gasifier 10 l ⁇ re ⁇ cuted, which makes the possible load rise slower
• the present invention solve this problem by arranging the regulating member 35 to open at a de- sire of a load increase, whereby the combustible gases from the accumulator tank 34 stored under high pressure are supplied to the topping combustor 8 and/or the reheating combustor 25
• the flue gas flow is m this way increased at these location and an ad- d tional power is obtained in the respective turbine 16 and 23 and also indirectly in the turbine 29, so that the gas turbines may directly deliver more power and increase the
• the load increase may by that be achieved very fast without any need whatso ⁇ ever of an initial lowering of the power of the power plant because of the gas turbine compressor directly requires more power for being able to press an in ⁇ creased air flow into the pressure vessel
• a regulating member 35 is preferably closed for being opened later on when a new load rise is desired from this level or from a lower level established after a load reduc ⁇
• the container for the second combu ⁇ tible ga ⁇ e ⁇ through another means than the gasifier, also in the case when a such one is present, for example through a ga ⁇ network, although exactly the combination of a ga ⁇ ifier and the connection thereof to a container for charging thereof through the former i ⁇ particularly advanta ⁇ geous and by that intere ⁇ ting.
• the first and second combustible gase ⁇ may but do not have to be of the same type, as is the case above.

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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)

Applications Claiming Priority (2)

Publications (1)

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ID=20400552

Family Applications (1)

Country Status (2)

Citations (4)

• 1995
  • 1995-12-11 SE SE9504430A patent/SE509988C2/sv not_active IP Right Cessation
• 1996
  • 1996-12-11 WO PCT/SE1996/001634 patent/WO1997021916A1/en active Application Filing

Patent Citations (4)

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