US3884036A - Steam plant with pressure-fired boiler - Google Patents

Steam plant with pressure-fired boiler Download PDF

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Publication number
US3884036A
US3884036A US419276A US41927673A US3884036A US 3884036 A US3884036 A US 3884036A US 419276 A US419276 A US 419276A US 41927673 A US41927673 A US 41927673A US 3884036 A US3884036 A US 3884036A
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United States
Prior art keywords
steam
gas turbine
pressure
gas
boiler
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Expired - Lifetime
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US419276A
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English (en)
Inventor
Hans Pfenninger
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BBC Brown Boveri AG Switzerland
BBC Brown Boveri France SA
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BBC Brown Boveri France SA
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    • 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
    • F01K13/00—General layout or general methods of operation of complete plants
    • F01K13/02—Controlling, e.g. stopping or starting
    • 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
    • F01K23/08—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 working fluid of one cycle heating the fluid in another cycle

Definitions

  • a steam power plant providing steam to drive a steam turbine coupled to an electrical generator includes a pressure-fired boiler the fuel flow rate of which is controlled by a livesteam regulator and a pressurecharging set consisting of turbocompressor for providing combustion air and which is driven by a gas turbine powered by the exhaust gas from the boiler and a starter motor, all on the same shaft.
  • the speed of the pressure-charging set is regulated by varying the throughput of the gas turbine and/or the temperature of the gas turbine inlet in such manner that it neither produces surplus power nor requires power from the outside in accordance with variations in the steam power demand from the boiler as the load on the steam turbine changes.
  • the starter motor for the pressure charging set is disconnected after starting and, at full load on the plant, the charging pressure for the combustion air is at least 9 bar, and the exhaust gas at the gas turbine outlet is no higher than 165.
  • Pressure-fired boilers for steam power plant have long been known under the name of Velox boilers.
  • the pressure-charging group is usually controlled by means of a Ward-Leonard set which is permanently coupled to the pressure-charging group.
  • the fuel flow rate is controlled in terms of steam consumption which at the same time influences the Ward-Leonard set in known manner and thus regulates the speed of the pressure-charging set, or in other words matches the required air flow rate to the fuel flow rate.
  • the power output of the gas turbine just covers the power requirement of the compressor.
  • the pressure-charging set consumes additional electrical power, while at higher part load, full load and overload surplus power is fed into the network.
  • the Ward Leonard configuration allows speed variation within broad limits, but has the disadvantage that the set runs continuously. It is also costly.
  • the impaired efficiency of the process due to the lower rise in feed water temperature can be counteracted in known manner by employing a combined process in which the gas turbine set, which at the same time serves to pressure charge the boiler, is operated at the maximum permissible temperature at the gas turbine inlet.
  • This method has the effect of reducing the steam output because the hot gases are cooled to a lesser extent in the boiler, but on the other hand the gas turbine produces useful power by way of a generator.
  • the losses due to the smaller rise in feed water temperature can just be overcome, but at the same time the following disadvantages must be taken into account:
  • the heat-exchange area of this nonpressurised heat exchanger is a multiple of those in the pressure-charged boiler.
  • the large volume of the heat exchanger also sharply increases the space required and the cost of the foundation.
  • the power produced must be divided between two generators, one for the gas turbine and one for the steam turbine, thus increasing the plant costs.
  • the gas turbine Since the gas turbine has a generator, its speed is constant and at part load the air rate cannot be reduced, or only at great expense, resulting in high exhaust losses. This can in fact be avoided by using a separate power turbine, but again the plant cost would be much higher.
  • the object of the invention is to create a structurally simple steam power plant of the kind mentioned above with good overall efficiency, such that on the gas side no additional heat exchanger is required after the pressure-fired boiler and yet the stack losses remain within the limits customary with such plant.
  • the speed of the pressure-charging set can be regulated by varying the throughput of the gas turbine and/or the temperature at the gas turbine inlet so that it neither produces surplus power nor requires power from outside, the starter motor can be disconnected after starting, at full load the charging pressure is at least 9 bar and the temperature of the gas turbine exhaust is no higher than C.
  • the speed, and hence also the air flow rate, is continuously matched to the fuel flow rate so that excess air in the boiler remains practically constant under all operating conditions and is restored immediately after load changes.
  • the high pressure ratio of the pressurecharging set means that the temperature of the compressed combustion air is high, allowing even heavy oil to be burned without difficulty and without the need for additional preheating of the air. Because of the high pressure ratio the dimensions of the steam generator can be small, allowing it to be transported in the assembled condition (packaged unit), and also the exhaust temperatures are low without the pressure-charging set sending out power so that no feed water heating by the exhaust gases is necessary and the thermal process can be optimised by heating the feed water with bleed steam.
  • the schematic, simplified drawing shows an example of the invention.
  • the steam power plant consists essentially of a high-pressure turbine 1 and a low-pressure turbine 2, which together drive the electric generator 3, of a condenser 4, condensate pump 32, feed water heaters 5, heated by bleed steam, and steam boiler 6 which includes a vaporizer section a and an economizer section 31 for pre-heating the returning feed water.
  • the boiler is pressurised, i.e. brought to the required gas-side pressure, by means of the pressure-charging set which basically comprises a turbocompressor 7, gas turbine 8, starter motor 9' and hydraulic coupling 10. All components of the pressure-charging set are mounted on the same shaft.
  • Gas turbine 8 is driven by the hot combustion gases discharged from the steam boiler 6, the temperature of the combustion gas delivered to the turbine inlet being controlled by a valve 29 which controls the amount of combustion gas permitted to by-pass the economizer section 31 through a by-pass duct 30. That is to say, when valve 29 is open part of the hot combustion gas exiting from the boiler by-passes the economizer section 31 by direct flow through duct 30 and the remaining part of the combustion gases pass through the economizer section 31 and are partially cooled off. The two partial gas flows mix and are thus delivered to the gas inlet of turbine 8. When valve 29 is closed, all of the combustion gas is forced to.
  • the control system of the plant includes the following individual components of interest in the present context: the steam pressure or flow rate in the live steam line 11 influence the live steam regulator 12 which controls drain 13 on pressure-oil line 14 of the v primary system, this line being fed at 15 by way of throttle 16.
  • Pressure-oil line 14 is connected at one end to servo 17, which regulates the fuel supply (not shown) via fuel nozzles 18 in the boiler, and at the other end to servo 19 which moves the cylinder 20 of centrifugal governor 21 of the pressure-charging set, whereupon the oil pressure in the pressure-oil line 23 of the secondary system is varied by means of drain 22.
  • Pressure-oil line 23 is fed at 24 by way of throttle 25 and leads to valve 26 on the bypass line 27 round gas turbine 8 and to the servo 28 which actuates valve 29, which in turn influences bypass 30 for the economizer section 31.
  • the hydraulic control system can also be replaced by an electrical control system with the same functions.
  • the turbocompressor 1 compresses the a combustion air to at least 9 bar, thus heating it to approx. 330C, which facilitates the burning of heavy oil.
  • the boiler 6 is so designed that the gas temperature at the outlet is approx. 430C, which is also the inlet temperature to the gas turbine 8. In association with the high pressure ratio, this results in an exhaust gas temperature after the gas turbine, and hence a stack temperature, of only 150C. The exhaust loss can thus be kept very low and a bulky extra heating surface avoided.
  • the turbocompressor has no form of cooling and thus the feed water does not have to be heated either by the compressed air or by the exhaust gas, which allows optimum heating by means of bleed steam.
  • the temperature at the gas turbine inlet is kept down, by the control system described below, to a value which just allows the gas turbine to drive the turbocompressor of the pressure-charging set.
  • the entire heat of expansion of the gas turbine passes to the compressor so that the pressure-charging set has the effect of the exhaust-gas-heated air heater required with known kinds of plant.
  • the pressure-charging set has the effect of the exhaust-gas-heated air heater required with known kinds of plant.
  • it generates a high pressure and thus reduces the boiler heating surface area to a fraction of that in a nonpressurised boiler.
  • the live steam regulator 12 closes drain 13 on pressure-oil line 14.
  • the pressure in the primary system then rises and, by way of servo 17, opens the fuel nozzles 18 in the boiler.
  • servo 19 moves the cylinder 20 of centrifugal governor 21 so that drain 22 is closed, thus raising the oil pressure in pressure-oil line 23 of the independent secondary system.
  • valve 26 in bypass line 27 round the gas turbine 8 closes, and servo 28 causes valve 29, and hence bypass 30 on the gas exit side of the boiler, to open.
  • the flow rate through the gas turbine increases and the temperature at the gas turbine inlet is raised; thus the speed of the pressure-charging set, or the combustion air flow rate, is adapted to the new, higher fuel rate.
  • valves 26 and 29 From the standpoint of efficiency it is of advantage not to actuate valves 26 and 29 simultaneously, but in the case of increasing demand for combustion air first to close bypass 27 round the gas turbine 8 and only then to open bypass 30 on the gas exit side of the boiler, and in the case of decreasing combustion air demand first to close 30 on the gas exit side of the boiler and then to open bypass 27 round the gas turbine 8.
  • the two control procedures can overlap to some degree, but it is also possible to leave a small neutral zone between them.
  • These various possibilities can easily be achieved by suitably selecting the spring forces of valve 26 and servo 28, in which case the spring of the servo must be the stronger.
  • bypass 30 on the gas exit side of boiler 6 opens at least temporarily in order to provide the combustion air flow needed for the higher fuel flow rate as quickly as possible, and closes again when the actual load decreases.
  • bypass 27 round gas turbine 8 opens temporarily in order to match the speed of the pressure-charging set as quickly as possible to the lower fuel rate. In this way the speed or combustion air rate can be matched as quickly as possible to the fuel rate.
  • the pressure-charging set can alter its speed with the live steam regulator 12 at a constant setting, i.e., at constant load. This happens if the outside air temperature fluctuates very widely, for example. in this case, too, the control system performs its function in full.
  • the entire control system can also be so designed that the pressure in pressure-oil lines 14 and 23 decreases when the live steam pressure falls, but the effects remain the same.
  • a combined steam and gas turbine plant comprising a pressure-fired boiler providing steam for driving a steam turbine coupled to a power consumer such as an electrical generator, means including a condenser at the discharge side of said steam turbine for converting the discharged steam into feed water and a return line for the feed water to the inlet side of said boiler for recycling, a heat exchanger for pre-heating the returned feed water by heat exchange with combustion gas at the gas discharge side of said boiler, a by-pass for the combustion gas passing through said heat exchanger, valve means for controlling said by-pass, the respective portions of the combustion gas put through said by-pass and through said heat exchanger being combined at the outlet thereof and delivered to the inlet of a gas turbine at a temperature variable in accordance with the portion of the gas put through said by-pass and constituting the sole motive fluid for driving said gas turbine, a livesteam regulator responsive to a change in load on the power plant for correspondingly regulating the fuel supply to said boiler and for regulating said valve means which controls the by-pass to said feed water heat exchange
US419276A 1972-12-01 1973-11-27 Steam plant with pressure-fired boiler Expired - Lifetime US3884036A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH1748172A CH552770A (de) 1972-12-01 1972-12-01 Dampfkraftanlage mit druckgefeuertem dampfkessel.

Publications (1)

Publication Number Publication Date
US3884036A true US3884036A (en) 1975-05-20

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US419276A Expired - Lifetime US3884036A (en) 1972-12-01 1973-11-27 Steam plant with pressure-fired boiler

Country Status (10)

Country Link
US (1) US3884036A (ja)
JP (1) JPS5321456B2 (ja)
AT (1) AT331584B (ja)
BE (1) BE807974A (ja)
CA (1) CA993664A (ja)
CH (1) CH552770A (ja)
DK (1) DK144834C (ja)
FR (1) FR2209393A5 (ja)
NL (1) NL169222C (ja)
SE (1) SE393660B (ja)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4175382A (en) * 1975-08-22 1979-11-27 Bbc Brown Boveri & Company Limited Steam power plant with pressure-fired boiler
NL2013536B1 (en) * 2014-09-26 2016-06-06 Innecs B V Method to provide a heated gas.
US9492780B2 (en) 2014-01-16 2016-11-15 Bha Altair, Llc Gas turbine inlet gas phase contaminant removal
US10502136B2 (en) 2014-10-06 2019-12-10 Bha Altair, Llc Filtration system for use in a gas turbine engine assembly and method of assembling thereof

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH592273A5 (ja) * 1975-08-22 1977-10-14 Bbc Brown Boveri & Cie
JPS59100088U (ja) * 1982-12-25 1984-07-06 太陽工業株式会社 パネルによる折りたたみ開閉式のドア構造

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2911789A (en) * 1958-08-27 1959-11-10 Gen Electric Regulating system for steam-gas turbine powerplant
US3203175A (en) * 1962-07-31 1965-08-31 Michalicka Ladislav System of operation of a steam-gas circuit or of a gas circuit for gas turbines comprising a combustion chamber for solid fuel
US3232052A (en) * 1962-12-28 1966-02-01 Creusot Forges Ateliers Power producing installation comprising a steam turbine and at least one gas turbine

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2911789A (en) * 1958-08-27 1959-11-10 Gen Electric Regulating system for steam-gas turbine powerplant
US3203175A (en) * 1962-07-31 1965-08-31 Michalicka Ladislav System of operation of a steam-gas circuit or of a gas circuit for gas turbines comprising a combustion chamber for solid fuel
US3232052A (en) * 1962-12-28 1966-02-01 Creusot Forges Ateliers Power producing installation comprising a steam turbine and at least one gas turbine

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4175382A (en) * 1975-08-22 1979-11-27 Bbc Brown Boveri & Company Limited Steam power plant with pressure-fired boiler
US9492780B2 (en) 2014-01-16 2016-11-15 Bha Altair, Llc Gas turbine inlet gas phase contaminant removal
NL2013536B1 (en) * 2014-09-26 2016-06-06 Innecs B V Method to provide a heated gas.
US10502136B2 (en) 2014-10-06 2019-12-10 Bha Altair, Llc Filtration system for use in a gas turbine engine assembly and method of assembling thereof

Also Published As

Publication number Publication date
BE807974A (fr) 1974-03-15
ATA791873A (de) 1975-11-15
DK144834C (da) 1982-11-29
SE393660B (sv) 1977-05-16
DK144834B (da) 1982-06-14
DE2262305A1 (de) 1974-06-20
JPS5321456B2 (ja) 1978-07-03
NL169222C (nl) 1982-06-16
FR2209393A5 (ja) 1974-06-28
NL169222B (nl) 1982-01-18
AT331584B (de) 1976-08-25
CH552770A (de) 1974-08-15
CA993664A (en) 1976-07-27
JPS4995053A (ja) 1974-09-10
DE2262305B2 (de) 1977-05-12
NL7316374A (ja) 1974-06-05

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