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
  • F01K3/00—Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein
  • F01K3/18—Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein having heaters
  • F01K3/26—Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein having heaters with heating by steam
  • F01K3/262—Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein having heaters with heating by steam by means of heat exchangers
• • 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
  • F01K7/00—Steam engine plants characterised by the use of specific types of engine; Plants or engines characterised by their use of special steam systems, cycles or processes; Control means specially adapted for such systems, cycles or processes; Use of withdrawn or exhaust steam for feed-water heating
  • F01K7/02—Steam engine plants characterised by the use of specific types of engine; Plants or engines characterised by their use of special steam systems, cycles or processes; Control means specially adapted for such systems, cycles or processes; Use of withdrawn or exhaust steam for feed-water heating the engines being of multiple-expansion type
  • F01K7/025—Consecutive expansion in a turbine or a positive displacement engine
• • 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
  • F01K7/00—Steam engine plants characterised by the use of specific types of engine; Plants or engines characterised by their use of special steam systems, cycles or processes; Control means specially adapted for such systems, cycles or processes; Use of withdrawn or exhaust steam for feed-water heating
  • F01K7/16—Steam engine plants characterised by the use of specific types of engine; Plants or engines characterised by their use of special steam systems, cycles or processes; Control means specially adapted for such systems, cycles or processes; Use of withdrawn or exhaust steam for feed-water heating the engines being only of turbine type
  • F01K7/22—Steam engine plants characterised by the use of specific types of engine; Plants or engines characterised by their use of special steam systems, cycles or processes; Control means specially adapted for such systems, cycles or processes; Use of withdrawn or exhaust steam for feed-water heating the engines being only of turbine type the turbines having inter-stage steam heating
• • 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
  • F01K7/00—Steam engine plants characterised by the use of specific types of engine; Plants or engines characterised by their use of special steam systems, cycles or processes; Control means specially adapted for such systems, cycles or processes; Use of withdrawn or exhaust steam for feed-water heating
  • F01K7/16—Steam engine plants characterised by the use of specific types of engine; Plants or engines characterised by their use of special steam systems, cycles or processes; Control means specially adapted for such systems, cycles or processes; Use of withdrawn or exhaust steam for feed-water heating the engines being only of turbine type
  • F01K7/22—Steam engine plants characterised by the use of specific types of engine; Plants or engines characterised by their use of special steam systems, cycles or processes; Control means specially adapted for such systems, cycles or processes; Use of withdrawn or exhaust steam for feed-water heating the engines being only of turbine type the turbines having inter-stage steam heating
  • F01K7/24—Control or safety means specially adapted therefor

Definitions

• the invention relates to a method for operating a power plant comprising a steam turbine, which is subdivided into a high-pressure turbine section, medium-pressure turbine section and low-pressure turbine section, and a reheater unit is arranged between the high-pressure turbine section and the medium-pressure turbine section.
• the invention relates to a power plant which is operated by the method according to the invention.
• Power plants in which large-volume steam turbines are used, u.a. used in the municipal energy supply.
• the steam turbines used in such power plants have relatively high masses and are usually designed for a given nominal power.
• These power plants which can also be referred to as conventional power plants, can be classified as a first approximation in pure steam power plants and in gas and steam power plants. Both have in common that fossil fuels are needed to generate electrical energy.
• Such power plants have hitherto been designed so that they were designed for a base load. Due to the increasing share of renewable energy sources, such as As the wind energy, which are not substantially controllable, the aforementioned conventional power plants must be operated more frequently in a partial load. This means that the power plants do not permanently deliver the nominal power, but deliver a percentage of the nominal power as a partial load. For example, the partial loads may in some cases be 25% of full load.
• the reheater heating surfaces were oversized and the hot reheater superheat temperature in the upper load range, for example, between 70% and 100%, regulated at the expense of the resulting thermodynamic loss of efficiency.
• the term "hZÜ" refers to the hot reheater temperature that is present after the reheater unit.
• Another approach is to limit the load gradients in the lower load range or to reduce the permissible load changes, whereby an increased wear is considered, so that the thick-walled components must be replaced early.
• the object is achieved by a power plant, which is operated by a method according to one of claims 1 to 5 and further by a power plant that is designed as a steam power plant or as a gas and steam power plant and operated by the method according to the invention.
• the invention is based on the idea that a frequent load change can still take place, but does not lead to a reduction in the service life of the components.
• the invention is based on the idea that the number of permissible load changes is generally not proportional to the temperature jump at the same temperature gradient. For example, a temperature jump of 30 Kelvin leads to about 1,000,000 permissible load changes, whereas a temperature jump of 60 Kelvin does not lead to a halving of the permissible load changes, but to a much smaller number of load changes, namely about 10,000 permissible load changes. Thus, when the temperature jump is doubled, the number of permissible load changes changes by one or more orders of magnitude.
• the above values are for illustrative purposes only.
• the number of permissible load changes as a function of the temperature jump strongly depend on the geometries of the components, the material properties as well as temperature levels and many other parameters.
• An essential feature of the invention is that the temperature of the reheater unit can be reduced by raising the inlet temperature to the reheater unit.
• the inlet temperature upstream of the reheater unit is also referred to as cold reheat.
• This increase in temperature is realized in that control valves that are throttled before the second expansion section, ie before the medium-pressure turbine section.
• the throttling reduces the expansion and thus the temperature reduction in the first expansion section, in this case in the high-pressure turbine section.
• the result is that there is an increase in load-dependent temperature fluctuations at the outlet of the high-pressure turbine section.
• the partial reheat waste of the reheater superheat temperature is reduced by raising the cold reheater temperature at the high pressure turbine exit.
• This temperature increase is achieved by targeted pressure increase in the reheater system at partial load by throttling the valves. If no throttling takes place, a partial load at one point would cause a temperature change of 60 Kelvin, for example on one component. Due to the throttling according to the invention, this temperature reduction of 60 Kelvin is counteracted and, for example, only a temperature reduction of 30 Kelvin is achieved, wherein this temperature reduction of 30 Kelvin is to be divided into two components. The permissible load changes thereby increase by more than an order of magnitude.
• the throttling is selected such that the amount of temperature reduction after the reheater unit is substantially halved in the unthrottled state.
• the throttling is controlled so that the load changes on all components then smaller temperature changes in the first approximation are the same size.
• a significant advantage of the invention is that now large load changes can be driven with significantly faster gradients and much more often in the life of the steam turbine. This leads to an overall increase in the lifetime.
• Conventional conventional power plants include a steam turbine that can be divided into a high-pressure turbine section, medium-pressure turbine section and low-pressure section turbine and a reheater unit, wherein the reheater unit between the high-pressure turbine section and the intermediate-pressure turbine section is arranged.
• a steam generator In front of the high-pressure turbine part, a steam generator generates a hot live steam, which flows through the high-pressure turbine section and then reheated in the reheater unit and then flows into the medium-pressure turbine section and then through the low-pressure turbine section. After the low-pressure turbine section, the steam condenses to water and is pumped back to the steam generator where it is converted back to steam.
• Such a power plant is designed for a rated power that is to be operated as permanently as possible at this nominal power level.
• a part-load operation which means that the power plant is operated at not 100% rated load, but at, for example, 25% of rated load, the temperatures in the reheater unit change.
• a control valve is arranged, which is throttled during operation of the partial load such that an increase in the temperature takes place at the entrance to the reheater unit.
• a controller controls the medium-pressure valve in such a way that the steam flow is throttled in such a way that the expansion in the high-pressure turbine part is reduced. In consequence of this reduction increases the temperature at the output of the high-pressure turbine section.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Control Of Turbines (AREA)

Priority Applications (8)

Applications Claiming Priority (1)

Publications (1)

Family

ID=48048014

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Citations (7)

Family Cites Families (11)

• 2012
  • 2012-04-04 EP EP20120163194 patent/EP2647802A1/de not_active Withdrawn
• 2013
  • 2013-03-27 CN CN201380018922.9A patent/CN104204425B/zh not_active Expired - Fee Related
  • 2013-03-27 PL PL13714254T patent/PL2805031T3/pl unknown
  • 2013-03-27 IN IN7231DEN2014 patent/IN2014DN07231A/en unknown
  • 2013-03-27 US US14/388,553 patent/US9574462B2/en not_active Expired - Fee Related
  • 2013-03-27 JP JP2015503823A patent/JP5985737B2/ja not_active Expired - Fee Related
  • 2013-03-27 EP EP13714254.3A patent/EP2805031B1/de not_active Not-in-force
  • 2013-03-27 WO PCT/EP2013/056496 patent/WO2013149900A1/de active Application Filing

Patent Citations (7)

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