CN110792481A - Cogeneration power generation system and control method thereof - Google Patents
Cogeneration power generation system and control method thereof Download PDFInfo
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- CN110792481A CN110792481A CN201910871279.3A CN201910871279A CN110792481A CN 110792481 A CN110792481 A CN 110792481A CN 201910871279 A CN201910871279 A CN 201910871279A CN 110792481 A CN110792481 A CN 110792481A
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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
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D15/00—Adaptations of machines or engines for special use; Combinations of engines with devices driven thereby
- F01D15/10—Adaptations for driving, or combinations with, electric generators
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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
- F01K11/00—Plants characterised by the engines being structurally combined with boilers or condensers
- F01K11/02—Plants characterised by the engines being structurally combined with boilers or condensers the engines being turbines
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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
- F01K17/00—Using steam or condensate extracted or exhausted from steam engine plant
- F01K17/02—Using steam or condensate extracted or exhausted from steam engine plant for heating purposes, e.g. industrial, domestic
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E20/00—Combustion technologies with mitigation potential
- Y02E20/14—Combined heat and power generation [CHP]
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Abstract
The invention discloses a cogeneration power generation system and a control method thereof. The power generation system comprises a three-in three-out cogeneration unit and a single-in single-out heat storage tank. The cogeneration unit comprises a steam turbine provided with a steam turbine controller, a steam extraction heat source provided with a steam extraction heat source controller and a boiler provided with a fuel quantity controller; the heat storage tank is provided with a heat storage tank controller, and the water flow in and out of the heat storage tank is controlled by a heat storage tank regulating valve. The control method of the power generation system responds to the power generation load demand by controlling the prior action of the steam extraction heat source regulating valve, and the heat storage tank heat release load makes up the part with insufficient heat source supply, so that the AGC performance of the unit can be obviously improved on the premise of ensuring the heat supply quality of the unit.
Description
Technical Field
The invention belongs to the field of generator set control, and particularly relates to a cogeneration power generation system and a control method thereof.
Background
In order to solve the problem of wind and light abandonment, flexible modification of thermal power generating units, particularly cogeneration units, has been widely developed in the three north areas of China. The configuration of the heat storage tank is one of important ways for realizing thermoelectric decoupling and deep peak regulation of the cogeneration unit and improving the operation flexibility of the unit. In consideration of complementarity of the heat storage tank to a heat source (heat supply extraction steam) of the unit and the quick response characteristic of the heat source to a power generation load, the quick load change control method of the cogeneration unit based on heat storage compensation of the heat storage tank is designed, is expected to further improve the automatic power generation control (AGC) performance of the cogeneration unit, and provides support for safe and stable operation of a power system and reliable guarantee of power quality.
Disclosure of Invention
The invention aims to provide a cogeneration power generation system and a control method thereof, wherein a heat storage tank mode is adopted to change the power generation load, the preferential action of a steam extraction heat source regulating valve is controlled to respond to the power generation load demand, and the heat storage tank heat release load makes up the part with insufficient heat source supply. The invention can obviously improve the AGC performance of the unit on the premise of ensuring the heat supply quality of the unit.
One aspect of the present invention provides a cogeneration power generation system, including a cogeneration unit and a heat storage tank, characterized in that:
the cogeneration unit is a three-input three-output system and comprises a steam turbine provided with a steam turbine controller, a steam extraction heat source provided with a steam extraction heat source controller and a boiler provided with a fuel quantity controller; the steam turbine controller controls main steam pressure through the opening of a main steam regulating valve, the steam extraction heat source controller controls the flow of a steam extraction heat source through a steam extraction heat source regulating valve, and the fuel quantity controller controls the power generation load of the cogeneration unit through controlling the fuel quantity;
the heat storage tank is a single-input single-output system and is provided with a heat storage tank controller, and the flow of inlet and outlet water of the heat storage tank is controlled by a heat storage tank regulating valve;
the boiler controller provides all energy requirements of electric heating loads by controlling fuel quantity, the steam extraction heat source is responsible for all heat supply of the cogeneration power generation system, and the fuel quantity of the boiler is designed to be the sum of the power generation load deviation of the cogeneration power generation system and the power generation load corresponding to the change of the steam extraction heat source; the method comprises the steps that the flow of a steam extraction heat source is controlled to distribute the electric heat load of the cogeneration unit, the electric load demand is met preferentially, and when the electric load deviates, the power generation load is adjusted, so that the load response rate of the cogeneration unit is improved;
the heat storage tank controller controls the heat source of the heat storage tank, is used for complementing the insufficient part of the supply of the extraction heat source, calculates the required heat source of the heat storage tank according to the deviation of the flow of the extraction heat source, supplies the target flow, and takes the difference with the actual flow supplied by the heat source of the heat storage tank as the input of the heat storage tank controller.
In another aspect of the present invention, there is provided a control method for a cogeneration power generation system of the above invention, the control method varying a power generation load by a heat storage tank method, wherein the power generation load corresponding to the change of the extraction heat source is expressed by a product of a deviation of a flow rate of the extraction heat source and a gain coefficient k, wherein the gain coefficient is obtained from a thermocouple characteristic model:
wherein, P represents the generating power of the cogeneration unit under the pure condensation heat supply working condition under the maximum boiler evaporation capacity, and P0Represents the generating power m of the cogeneration unit under the rated heat supply working condition under the maximum boiler evaporation capacityHIndicating the deviation of the flow of the extracted steam heat source.
Preferably, the control method for a cogeneration system of the present invention described above, wherein the target flow rate supplied from the heat source of the heat storage tank is represented by a product of a deviation of the flow rate of the extraction heat source and a proportionality coefficient C, that is:
wherein m isHAspIndicates the target flow rate, hHDenotes the extraction enthalpy, hdDenotes the extraction steam and drainage enthalpy, houtIndicating the enthalpy of the effluent, h, of the heat supplyinIndicating heat supplyEnthalpy of return, △ mHIndicating the deviation of the flow of the extracted steam heat source.
Further, the control method for the cogeneration system of the invention described above includes the steps of:
(1) when the generating load instruction of the unit changes, the flow of the steam extraction heat source is changed by controlling the opening of the steam extraction heat source regulating valve, so that the instantaneous response rate of the electric load is improved, and the demand of the electric load is met preferentially;
(2) when the step (1) is executed, after the equivalent power generation load output corresponding to the flow change of the steam extraction heat source is superposed with the power generation load deviation, the equivalent power generation load output and the power generation load deviation are sent to a fuel quantity controller together, and the fuel quantity output of the controller is ensured to meet the requirement of the total electric heating load at any moment;
(3) and (3) converting insufficient heat supply caused by the flow change of the steam extraction heat source into required heat storage tank heat source supply target flow while executing the step (1), and taking the difference with the actual heat storage tank heat source supply flow as the input of a heat storage tank controller to control the heat storage tank heat source to make up the insufficient heat supply caused by the flow change of the steam extraction heat source.
The invention has the advantages of realizing the rapid variable load control of the cogeneration unit and the automatic compensation of the heat storage tank.
Drawings
FIG. 1 is a diagram showing a cogeneration power generation system of the invention and a control method thereof
FIG. 2 is a power generation load response curve
FIG. 3 is a flow chart of the heat source of the steam extraction heat source and the heat storage tank
Detailed Description
The present invention provides a cogeneration power generation system and a control method thereof, and the present invention will be described in detail with reference to the accompanying drawings and specific embodiments.
Fig. 1 is a schematic view showing a control method of a cogeneration power generation system of the present invention. As shown in fig. 1, the cogeneration power generation system of the invention includes a cogeneration unit system and a heat storage tank system. The cogeneration unit is a three-input three-output system and is provided with a steam turbine controller (PID), a steam extraction heat source controller (PID) and a boiler fuel quantity controller (PID); the heat storage tank is a single-input single-output system and is provided with a heat storage tank controller (PID). The system can control the main steam pressure, the steam extraction heat source flow and the power generation load of the cogeneration unit through a steam turbine controller (PID), a steam extraction heat source controller (PID) and a boiler fuel quantity controller (PID) respectively, and the heat storage tank controller (PID) controls the water flow rate of the heat storage tank through a heat storage tank regulating valve.
The control method of the cogeneration system is set as follows:
1. the input of the fuel quantity control is the sum of the power generation load corresponding to the power generation load deviation and the change of the steam extraction heat source.
2. The input of the steam extraction heat source control is the power generation load deviation.
3. The input to the heat storage tank heat source control is the deviation between the heat storage tank heat source supply target flow and the heat storage tank heat source actual flow.
4. The input to the steam turbine control is the deviation of the main steam pressure command from the actual main steam pressure.
In the above strategy, the power generation load corresponding to the change of the extraction heat source is obtained by multiplying the extraction heat source deviation by a gain coefficient k, where k is represented by the following formula:
wherein, P represents the generating power of the cogeneration unit under the pure condensation heat supply working condition under the maximum boiler evaporation capacity, and P0Represents the generating power m of the cogeneration unit under the rated heat supply working condition under the maximum boiler evaporation capacityHIndicating the deviation of the flow of the extracted steam heat source.
Taking a 670MW cogeneration unit as an example, the steam inlet volume of the steam turbine under the pure condensation and rated heat supply working conditions under the maximum boiler evaporation capacity is 2009.628t/h, and the generating power is P, P0714.569MW and 638.608MW respectively, and the rated heat supply extraction flow is as follows: 335t/h, its gain factor k is (714.569-638.608)/(335-0) 0.22675.
The heat source supply target flow rate of the heat storage tank is represented by the product of the deviation of the flow rate of the extraction heat source and a proportionality coefficient C, which is represented by the following formula:
wherein h isHDenotes the extraction enthalpy, hdDenotes the extraction steam and drainage enthalpy, houtIndicating the enthalpy of the effluent, h, of the heat supplyinRepresenting the return enthalpy of the heating.
Take 670MW cogeneration unit as an example, its extraction enthalpy hH3008.4kJ/kg, its extraction steam-drainage enthalpy hd311.7kJ/kg, hot effluent houtAnd enthalpy of backwater hin549.2kJ/kg and 315.56kJ/kg, respectively, the proportionality coefficient is as follows:
the initial working condition of the unit is a rated heating working condition, when the unit is in a steady state working condition, a step of +10MW is applied to the power generation load instruction of the unit at the 120 th s, and a step of-20 MW is applied to the load instruction at the 180 th s after the standby unit is stabilized, and the simulation results are shown in fig. 2 and 3. It can be seen from fig. 2 that the variable load performance of the strategy provided by the invention is significantly superior to that of the traditional coordination control method, and fig. 3 shows the heat load output condition and the heat release condition of the heat storage tank in the variable load process, which proves the effectiveness of the cogeneration system and the control method thereof disclosed by the invention.
Claims (4)
1. The utility model provides a combined heat and power generation system, includes cogeneration unit, heat accumulation jar, its characterized in that:
the cogeneration unit is a three-input three-output system and comprises a steam turbine provided with a steam turbine controller, a steam extraction heat source provided with a steam extraction heat source controller and a boiler provided with a fuel quantity controller; the steam turbine controller controls main steam pressure through the opening of a main steam regulating valve, the steam extraction heat source controller controls the flow of a steam extraction heat source through a steam extraction heat source regulating valve, and the fuel quantity controller controls the power generation load of the cogeneration unit through controlling the fuel quantity;
the heat storage tank is a 'single-in single-out' system and is provided with a heat storage tank controller, and the flow of inlet and outlet water of the heat storage tank is controlled by a heat storage tank regulating valve;
the boiler controller provides all energy requirements of electric heating loads by controlling fuel quantity, the steam extraction heat source is responsible for all heat supply of cogeneration, and the fuel quantity of the boiler is designed to be the sum of the power generation load deviation of the cogeneration and the power generation load corresponding to the change of the steam extraction heat source; the method comprises the steps that the flow of a steam extraction heat source is controlled to distribute the electric heat load of the cogeneration unit, the electric load demand is met preferentially, and when the electric load deviates, the power generation load is adjusted, so that the load response rate of the cogeneration unit is improved;
the heat storage tank controller controls the heat source of the heat storage tank, is used for complementing the insufficient part of the supply of the extraction heat source, calculates the required heat source of the heat storage tank according to the deviation of the flow of the extraction heat source, supplies the target flow, and takes the difference with the actual flow supplied by the heat source of the heat storage tank as the input of the heat storage tank controller.
2. A control method for a cogeneration power generation system in accordance with claim 1, wherein the power generation load corresponding to the change of the extraction heat source is represented by a product of a deviation of the flow rate of the extraction heat source and a gain coefficient k obtained from a model of the thermoelectric coupling characteristics:
wherein, P represents the generating power of the cogeneration unit under the pure condensation heat supply working condition under the maximum boiler evaporation capacity, and P0Represents the generating power m of the cogeneration unit under the rated heat supply working condition under the maximum boiler evaporation capacityHIndicating the deviation of the flow of the extracted steam heat source.
3. A control method of a cogeneration power system according to claim 2, wherein the target flow rate supplied from the heat source of the heat storage tank is represented by the product of the deviation of the flow rate of the extraction heat source and the proportionality coefficient C, that is:
wherein m isHAspIndicates the target flow rate, hHDenotes the extraction enthalpy, hdDenotes the extraction steam and drainage enthalpy, houtIndicating the enthalpy of the effluent, h, of the heat supplyinIndicating the enthalpy of return of heat supply, △ mHIndicating the deviation of the flow of the extracted steam heat source.
4. A control method of a cogeneration power system in accordance with claim 2, comprising the steps of:
(1) when the generating load instruction of the unit changes, the flow of the steam extraction heat source is changed by controlling the opening of the steam extraction heat source regulating valve, so that the instantaneous response rate of the electric load is improved, and the demand of the electric load is met preferentially;
(2) when the step (1) is executed, after the equivalent power generation load output corresponding to the flow change of the steam extraction heat source and the power generation load deviation are superposed, the equivalent power generation load output and the power generation load deviation are sent to a fuel quantity controller together, and the fuel quantity output is ensured to meet the requirement of the total electric heating load at any moment;
(3) and (3) converting insufficient heat supply caused by the flow change of the steam extraction heat source into required heat storage tank heat source supply target flow while executing the step (1), and taking the difference with the actual heat storage tank heat source supply flow as the input of a heat storage tank controller to control the heat storage tank heat source to make up the insufficient heat supply caused by the flow change of the steam extraction heat source.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112344413A (en) * | 2020-10-30 | 2021-02-09 | 广西电网有限责任公司电力科学研究院 | Low-pressure steam source boosting and heat supplying method for cogeneration unit |
| CN114856740A (en) * | 2022-06-10 | 2022-08-05 | 西安交通大学 | Flexible regulation and control system and method based on adjustable heat source coupling steam jet flow heat storage unit |
| CN115013100A (en) * | 2022-06-10 | 2022-09-06 | 西安交通大学 | Coupling steam jet condensation heat storage cogeneration unit flexible regulation and control system and method |
| CN115218245A (en) * | 2022-07-21 | 2022-10-21 | 西安热工研究院有限公司 | Control method and system for improving flexibility of unit through heat supply steam extraction throttling |
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