CN113864848B - Full-working-condition efficient heat supply system and method for cogeneration unit - Google Patents
Full-working-condition efficient heat supply system and method for cogeneration unit Download PDFInfo
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
- F24D1/00—Steam central heating systems
- F24D1/08—Feed-line arrangements, e.g. providing for heat-accumulator tanks, expansion tanks
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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
- F01D17/00—Regulating or controlling by varying flow
- F01D17/10—Final actuators
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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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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
- F24D19/00—Details
- F24D19/10—Arrangement or mounting of control or safety devices
- F24D19/1003—Arrangement or mounting of control or safety devices for steam heating systems
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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 application relates to a heat and power cogeneration unit full-working-condition efficient heat supply system and a method, wherein the system comprises a medium pressure cylinder and a plurality of low pressure cylinders which are communicated with a heat steam source, the low pressure cylinders are decoupled into separate cylinder independent arrangement structures by conventional cylinder combination arrangement, the low pressure cylinders are respectively communicated with steam exhaust pipelines of outlets of the medium pressure cylinders, a butterfly valve is arranged on a main steam exhaust pipe of the medium pressure cylinder, the butterfly valve is communicated with a low pressure cylinder branch of each independent separate cylinder arrangement, a first valve is arranged on each branch, and the method comprises the step of supplying steam pressure P under the full-opening state of the butterfly valve and the first valve Steam supply Meet the pressure requirement P of heat supply and steam supply Demand for When the device is operated according to the existing operation mode; when P Steam supply <P Demand for And when the valve is in use, the first valve and the butterfly valve are cooperatively regulated and controlled to realize efficient steam supply. The system and the method can obviously reduce the steam throttling loss generated for meeting the heat supply pressure requirement, thereby effectively improving the energy efficiency of the unit, greatly reducing the fuel consumption and realizing energy conservation and emission reduction.
Description
Technical Field
The application relates to the technical field of heat and power cogeneration heat supply and steam supply, in particular to an all-condition efficient heat supply system and method of a heat and power cogeneration unit.
Background
The cogeneration is a high-efficiency energy supply form based on energy cascade utilization, and is widely applied to the fields of resident heating, industrial steam supply and the like. In general, there is a need for heating (steam) pressure, for example, residential heating steam pressure may require up to 0.4MPa (corresponding to a steam saturation temperature of about 140 degrees celsius), and industrial steam pressure may require up to 0.785MPa (corresponding to a steam saturation temperature of about 170 degrees celsius). When the flow rate of the steam through flow in the steam turbine is smaller, the steam supply of the cogeneration unit is difficult to reach the corresponding required pressure. Therefore, the cogeneration unit mostly adopts devices such as butterfly valves, and the like, and utilizes throttling pressure holding to improve the steam supply pressure. However, the pressure loss of the steam is huge, and the acting capacity of the steam is greatEnergy) is significantly reduced, thereby greatly reducing the energy efficiency and thermal economy of the unit. Along with the acceleration of the energy transformation process in China, the share of new energy power is rapidly increased, and the large-scale grid connection of intermittent new energy power is faced, so that the cogeneration unit is taken as a main body of northern power in China to comprehensively participate in deep peak regulation, and is operated under the working condition of medium and low electric load for a long time, and the problem that the energy efficiency is greatly reduced due to frequent throttling and pressure holding of the cogeneration unit is solved in order to meet the corresponding steam supply pressure requirement.
Disclosure of Invention
The application mainly aims to solve the problem of low energy efficiency of the conventional cogeneration unit, and provides a high-efficiency heat supply method of the system while providing a full-working-condition high-efficiency heat supply system of the cogeneration unit.
Wherein, a high-efficient heating system of full operating mode of cogeneration unit, include with the well pneumatic cylinder of hot vapour source intercommunication and with the low pressure cylinder of a plurality of every well pneumatic cylinder intercommunication, its characterized in that: the low pressure cylinder is decoupled into a separate cylinder independent arrangement structure by conventional cylinder combination arrangement, is respectively communicated with a steam exhaust pipeline of an outlet of the medium pressure cylinder, a butterfly valve is arranged on a steam exhaust main pipe of the medium pressure cylinder, is communicated with a low pressure cylinder branch of each independent separate cylinder arrangement, and is provided with a first valve on each branch.
Further, the butterfly valve is connected with a first processor for controlling the opening degree of the butterfly valve.
Further, a first valve on a pipeline where each low-pressure cylinder is communicated with the butterfly valve and a second valve arranged on a pipeline between the low-pressure cylinders and the condenser are respectively connected with a second processor for controlling the opening and closing of the low-pressure cylinders and the butterfly valve.
Further, a first pressure gauge for detecting steam pressure in the pipeline is arranged in the pipeline between the medium pressure cylinder and the butterfly valve, the first pressure gauge is connected with the first processor, the first pressure gauge sends detected steam supply pressure information to the first processor, and the first processor controls the opening of the butterfly valve according to the steam supply pressure condition of the first pressure gauge.
Further, a second pressure gauge for detecting the inlet steam pressure of the low pressure cylinder is arranged in a pipeline between the low pressure cylinder and each valve, the second pressure gauge sends detected steam pressure information to a second processor, and the second processor controls the opening and closing of each first valve and each second valve according to control logic.
The application provides a full-working-condition efficient heat supply method for a cogeneration unit, which is characterized by comprising the following steps of:
step 1, obtaining steam supply pressure P Steam supply Low pressure cylinder inlet vapor pressure P Low pressure cylinder ；
Step 2, when the butterfly valve, the first valve and the second valve are all opened, and the steam supply pressure meets the steam supply pressure requirement, namely P Steam supply ≥P Demand for Operating according to the existing operation mode; when P Steam supply <P Demand for When the first valves are closedThe door and the corresponding second valve, i.e. selectively closing a plurality of low-pressure cylinders to reduce the number of low-pressure cylinders with through flow and increase the steam flow G of the remaining low-pressure cylinders with through flow g Increasing the low pressure cylinder inlet vapor pressure P Low pressure cylinder Thereby improving the steam supply pressure P Steam supply . The number of the low-pressure cylinders in operation in each working condition is n, wherein the number n of the low-pressure cylinders in operation corresponds to an nth operation mode.
Further, the method for determining the number of the low-pressure cylinders operated in each working condition in the step 2 specifically includes:
a, when the butterfly valve is fully opened and the first valve and the second valve are fully opened, the steam supply pressure just meets the steam supply pressure requirement, namely P Steam supply ＝P Demand for When the corresponding total steam flow G of the low-pressure cylinder is obtained 1 Steam flow G of each low-pressure cylinder g ＝G 1 /n；
b, obtaining the total mass flow G of low-pressure cylinder through-flow steam under the specific working condition according to principle thermodynamic calculation of a thermodynamic power plant Working conditions of Dividing G into n operation modes according to different through flow numbers of the low-pressure cylinders Working conditions of Divided by the number of through-flows of the low-pressure cylinders in the n operation modes, respectively, to estimate the steam flow (G Working condition 1 ，G Working condition 2 ，G Working condition 3 ，…，G Working condition n ) Steam flow and G of each low pressure cylinder under the n operation modes g Comparing, optimizing n low-pressure cylinder operation modes by taking the highest unit energy efficiency as an optimization target, and determining the value of the low-pressure cylinder through-flow quantity m in the optimized mode, wherein m is 1-n.
Further, in the step b, n low-pressure cylinder operation modes are optimized, and the method for determining the value of the low-pressure cylinder through-flow quantity m comprises the following steps:
when G Working condition n ≥G g When the working conditions are met, the n low-pressure cylinders are all in a through-flow state, namely m=n, which is a preferable operation mode under the working conditions;
when G Working condition 1 ≤G g When the low-pressure cylinder is in a through-flow state, the low-pressure cylinder is in a preferable operation mode under the working condition, namely m=1;
when G Working condition j ≥G g ≥G Working condition j+1 And when j=1, 2, … and n-1, performing performance evaluation on the 2 operation modes of through flow of j low-pressure cylinders and j+1 low-pressure cylinders based on principle thermodynamic calculation of the thermodynamic power plant, and taking the operation mode with the minimum power supply standard coal consumption as a preferred mode by taking the power supply standard coal consumption as an objective function.
Further, the method further comprises:
step 3, when the number of through-flows of the low-pressure cylinder is m, the steam supply pressure is still lower than the steam supply pressure requirement, namely P Steam supply <P Demand for The opening degree of the butterfly valve is regulated down until the steam supply pressure is equal to the steam supply demand pressure through throttling and pressure holding, P Steam supply ＝P Demand for 。
Further, the method further comprises: and step 4, optimizing the operation modes of all the operation working conditions of the cogeneration unit, thereby determining the corresponding relation between the low-pressure cylinder through-flow quantity and the specific working conditions in the optimized mode and obtaining the high-efficiency heat supply steam operation mode of the cogeneration unit under the whole working conditions.
The application has the beneficial effects that:
through the improvement of the system structure of the cogeneration unit and the optimization of the operation mode under all working conditions, the steam throttling loss generated for meeting the heat supply (steam) pressure requirement can be obviously reducedLoss), thereby effectively improving the energy efficiency of the unit, greatly reducing the fuel consumption and realizing energy conservation and emission reduction.
Drawings
FIG. 1 is a schematic diagram of a system architecture of the present application;
FIG. 2 is a flow chart of the method of the present application;
FIG. 3 is a diagram of a corresponding preferred mode of operation under full operating conditions for cogeneration in the example;
fig. 4 is a graph of power supply standard coal consumption energy saving effect in the case of the embodiment;
in the figure, a 1-medium pressure cylinder; 2-a low pressure cylinder; 3-butterfly valve; 4-a first valve; 5-a second valve; 6-a steam supply pressure measuring point of the first pressure gauge; 7-the low pressure cylinder inlet vapor pressure measurement point of the second pressure gauge.
Detailed Description
The embodiment of the application provides a full-working-condition efficient heat supply system and method for a cogeneration unit.
The terms "first," "second," "third," "fourth" and the like in the description and in the claims and in the above drawings, if any, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments described herein may be implemented in other sequences than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed or inherent to such process, method, article, or apparatus.
For ease of understanding, the following describes specific flows of systems and methods according to embodiments of the present application.
As shown in figure 1, the full-working-condition efficient heat supply system of the cogeneration unit comprises a medium pressure cylinder 1 communicated with a heat steam source and a plurality of low pressure cylinders 2 communicated with each medium pressure cylinder, wherein the low pressure cylinders are decoupled into separate-cylinder independent arrangement structures by conventional combined-cylinder arrangement and are respectively communicated with steam exhaust pipelines of outlets of the medium pressure cylinders, butterfly valves 3 are arranged on medium pressure cylinder steam exhaust main pipes, the butterfly valves are communicated with low pressure cylinder branches arranged independently and are provided with first valves 4 on respective branches, each low pressure cylinder is communicated with a condenser through a second valve 5, the first valves 4 and the second valves 5 can adopt electric valves, the butterfly valves are connected with first processors for controlling opening degrees of the butterfly valves, the first valves 4 and the second valves 5 are respectively connected with second processors for controlling opening and closing of the butterfly valves, and the opening degrees or opening and closing of the butterfly valves, the first valves and the second valves can be controlled through the respective processors.
A first pressure gauge 6 for detecting steam supply pressure is arranged in a pipeline between the medium pressure cylinder 1 and the butterfly valve 3, the first pressure gauge 6 is connected with the first processor, the first pressure gauge 6 sends detected steam supply pressure information to the first processor, and the first processor controls the opening of the butterfly valve according to the steam supply pressure condition of the first pressure gauge 6.
The low pressure cylinder 2 is internally provided with a second pressure gauge 7 for detecting the steam pressure at the inlet of the low pressure cylinder, the second pressure gauge sends detected steam pressure information to a second processor, and the second processor controls the first valve and the second valve to be opened and closed simultaneously.
In the system, through changing the layout structure and the communication mode of the medium pressure cylinder and the low pressure cylinder, when the low pressure cylinder of the cogeneration unit is provided with n (n is more than or equal to 2) cylinders and the butterfly valve, the first valve and the second valve are all in an open state, the steam flow of the low pressure cylinder is too small to cause the steam supply pressure P Steam supply Too small to meet the steam supply pressure requirement, i.e. P Steam supply <P Demand for The number of low-pressure cylinders through the flow can be reduced by closing part of the valves 1-n, so that the steam flow of the single (each) low-pressure cylinder through the flow is increased, and the inlet pressure P of the low-pressure cylinder is improved Low pressure cylinder Thereby improving the steam supply pressure P Steam supply . According to the different through-flow quantity of the low-pressure cylinders, the steam turbine has n running modes, namely, a single (low-pressure) cylinder, a double cylinder, a … cylinder and an n-cylinder.
When the steam flow of the low-pressure cylinder is too small and the cylinder cutting operation is performed, the steam supply pressure is still lower than the steam supply pressure requirement, namely P Steam supply <P Demand for At this time, butterfly valve throttling is needed, when the steam flow of the low pressure cylinder is too small and cylinder cutting operation is performed, the steam supply pressure is higher than the steam supply pressure requirement, namely P Steam supply >P Demand for At this time, butterfly valve throttling is not needed.
Through the system, the efficiency of the unit can be effectively improved.
Specifically, the embodiment also provides a specific method for improving the efficiency of the system, which is described as follows:
the variable working condition characteristics of the steam turbine are as follows: in the vaporWhen the back pressure of the turbine is fixed, the larger the flow of the steam through flow in the steam turbine stage is, the larger the pressure before the steam turbine stage is, and the pressure P before the ith stage of the steam turbine stage under the variable load working condition can be obtained by the formula (1) 1,i 。
Wherein G is 0 ,P 0,i ,P 0,i+1 ,T 0,i The steam flow of the ith stage is the steam flow of the steam turbine under the design working condition, the steam pressure before the stage, the steam pressure after the stage and the inlet steam temperature before the stage; g 1 ,P 1,i ,P 1,i+1 ,T 1,i The steam flow of the ith stage of the steam turbine under the variable load working condition, the steam pressure before the stage, the steam pressure after the stage and the inlet steam temperature before the stage are respectively.
The steam supply pressure of the cogeneration unit can be obtained according to the above formula (1). When the steam flow rate is lower in the operation working condition of the steam turbine, the steam supply pressure is lower, and the steam supply pressure requirement cannot be met. To make the steam supply pressure reach the requirement P Demand for A butterfly valve is arranged as shown in figure 1, and the opening of the butterfly valve is adjusted to enable steam to generate throttling pressure to meet the steam supply pressure requirement, namely P Steam supply ＝P Demand for . The low pressure cylinder inlet vapor pressure P of FIG. 1 Low pressure cylinder The steam supply pressure is the steam supply pressure when the butterfly valve is not arranged; exhaust pressure P of medium pressure cylinder Steam supply The steam supply pressure is reached after the steam throttling is suppressed. The steam throttling causing pressure lossLoss delta E Throttling The water and water vapor related properties can be found by the formula (2):
wherein h is steam enthalpy, s is steam entropy, T amb Is ambient temperature.
Step 1, determining the time according to the modification formula (3) of the formula (1)The steam supply pressure is the steam supply pressure requirement (i.e. P Steam supply ＝P Demand for ) Steam flow G of single low pressure cylinder g
Step 2, when the butterfly valve, the first valve and the second valve are all opened, and the steam supply pressure meets the steam supply pressure requirement, namely P Steam supply ≥P Demand for Operating according to the existing operation mode; when P Steam supply <P Demand for When the valve is in the open state, the first valves and the second valves are closed, i.e. the low pressure cylinders are closed to reduce the number of low pressure cylinders with through flow and increase the steam flow G of the low pressure cylinders with residual through flow g Increasing the low pressure cylinder inlet vapor pressure P Low pressure cylinder Thereby improving the steam supply pressure P Steam supply . The number of the low-pressure cylinders in operation in each working condition is n, wherein the number n of the low-pressure cylinders in operation corresponds to an nth operation mode.
The method for determining the number of the low-pressure cylinders operated in each working condition in the step 2 specifically includes:
a, when the butterfly valve is fully opened and the first valve and the second valve are fully opened, the steam supply pressure just meets the steam supply pressure requirement, namely P Steam supply ＝P Demand for When the corresponding total steam flow G of the low-pressure cylinder is obtained 1 Steam flow G of each low-pressure cylinder g ＝G 1 /n；
b, obtaining the total mass flow G of low-pressure cylinder through-flow steam under the specific working condition according to principle thermodynamic calculation of a thermodynamic power plant Working conditions of Dividing G into n operation modes according to different through flow numbers of the low-pressure cylinders Working conditions of Divided by the number of through-flows of the low-pressure cylinders in the n operation modes, respectively, to estimate the steam flow (G Working condition 1 ，G Working condition 2 ，G Working condition 3 ，…，G Working condition n ) Steam flow and G of each low pressure cylinder under the n operation modes g Comparing and optimizing the highest energy efficiency of the unitAnd (3) optimizing n low-pressure cylinder operation modes, and determining the value of the low-pressure cylinder through-flow quantity m in the optimized mode.
It should be further described in detail that, in the step b, n low-pressure cylinder operation modes are preferably selected, and the method for determining the value of the low-pressure cylinder through-flow quantity m includes:
when G Working condition n ≥G g When the working conditions are met, the n low-pressure cylinders are all in a through-flow state, namely m=n, which is a preferable operation mode under the working conditions;
when G Working condition 1 ≤G g When the low-pressure cylinder is in a through-flow state, the low-pressure cylinder is in a preferable operation mode under the working condition, namely m=1;
when G Working condition j ≥G g ≥G Working condition j+1 And when j=1, 2, … and n-1, performing performance evaluation on the 2 operation modes of through flow of j low-pressure cylinders and j+1 low-pressure cylinders based on principle thermodynamic calculation of the thermodynamic power plant, and taking the operation mode with the minimum power supply standard coal consumption as a preferred mode by taking the power supply standard coal consumption as an objective function.
The method further comprises the steps of:
step 3, when the number of through-flows of the low-pressure cylinder is m, the steam supply pressure is still lower than the steam supply pressure requirement, namely P Steam supply <P Demand for The opening degree of the butterfly valve is regulated down until the steam supply pressure is equal to the steam supply demand pressure through throttling and pressure holding, P Steam supply ＝P Demand for 。
The method further comprises the steps of: and 4, optimizing the operation modes of all the operation working conditions of the cogeneration unit, thereby determining the corresponding relation between the through-flow quantity of the low-pressure cylinder and the specific working conditions in the optimized mode and obtaining the efficient heat (steam) supply operation mode of the cogeneration unit under the whole working conditions.
The embodiment can obviously reduce the working capacity loss caused by throttling pressure loss generated for meeting the heat supply (steam) pressure requirement through optimizing the operation mode of the cogeneration unit under the full working conditionLoss), thereby effectively improving the energy efficiency of the unit, greatly reducing the fuel consumption and realizing the savingCan reduce the emission.
A more intuitive effect is obtained in connection with one case below.
And a certain 330MW cogeneration heat supply unit extracts the exhaust steam of the medium-pressure cylinder as a heat supply steam source, and the steam supply pressure requirement is 0.785MPa. Under the rated heat supply (steam) working condition, the main steam flow is 1002.4t/h, the main steam pressure is 16.67MPa, the total steam mass flow of the inlet of the low-pressure cylinder is 409.08t/h, and at the moment, the inlet pressure P of the low-pressure cylinder Low pressure cylinder =0.451 MPa, enthalpy 3130.5kJ/kg, temperature 331.37 ℃, ambient temperature 25 ℃, calculated from formula (2) aboveA value of 836.01kJ/kg; in order to meet the requirement of steam supply pressure, the steam discharge pressure (namely the steam supply pressure) of the medium pressure cylinder is 0.785MPa after the butterfly valve is used for suppressing the pressure and throttling, the enthalpy value is 3130.5kJ/kg, the temperature is 334.7 ℃, and the steam (i.e. the steam) is calculated by the above formula (2)>The value was 911.38kJ/kg. Steam per unit mass due to pressure build-up>Loss of delta E Throttling = 75.37kJ/kg, total->Loss of 8.56 MW->The efficiency is 91.73%, and the power supply standard coal consumption of the cogeneration unit is 237.15g/kWh.
According to the application, the low-pressure cylinder combination arrangement of the unit is decoupled into separate cylinder independent arrangements, so that the unit has 4 low-pressure cylinders. G is calculated according to the above formula (3) g 180t/h. At this time, the mass flow rate of the steam in each low-pressure cylinder in each operation mode is preliminarily estimated: the first valve 4 and the second valve 4 are closed, and the operation is carried out in a mode of 3 low-pressure cylinder through flows, wherein the steam mass flow in each low-pressure cylinder is 136t/h, namely G Working condition 3 <G g The method comprises the steps of carrying out a first treatment on the surface of the The first and second valves 3 and 4 are closed and the operation is carried out in a mode of 2 low-pressure cylinders through-flow, wherein the steam mass flow in each low-pressure cylinder is 205t/h, namely G Working condition 2 >G g . Therefore, the above two modes are preferable.
According to the principle thermodynamic calculation of a thermal power plant, when using 3 low-pressure cylinder through-flow operating modes, P is Low pressure cylinder =0.607 MPa, and the pressure P of steam supply after pressure holding and throttling by butterfly valve Steam supply =0.785 MPa, at this time, the power supply standard coal consumption of the cogeneration unit is 233.59g/kWh; in the operating mode with 2 low-pressure cylinder throughflows, P is the same Low pressure cylinder ＝0.960MPa，P Steam supply =0.980 MPa, butterfly valve pressure holding throttling is not needed, and at the moment, the power supply standard coal consumption of the cogeneration unit is 233.15g/kWh. Therefore, the operation mode of adopting 2 low-pressure cylinder through flows is the preferable operation mode under the load working condition, and compared with the conventional operation mode, the standard coal consumption can be reduced by 4g/kWh.
By adopting the same steps, the operation mode of the cogeneration unit under the full working condition is optimized, the corresponding optimized operation mode under the full working condition of the cogeneration unit is shown in the figure 3, the corresponding power supply standard coal consumption energy-saving effect is shown in the figure 4, and the result shows that the standard coal consumption can be reduced by 10-20 g/kWh under most working conditions by adopting the method for efficiently supplying heat (steam) under the full working condition of the cogeneration unit and the operation mode thereof, which are provided by the application.
The above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application.
Claims (6)
1. The utility model provides a high-efficient heating system of full operating mode of cogeneration unit, includes the well pressure jar that communicates with the hot vapour source and with a plurality of low pressure jar of every well pressure jar intercommunication, its characterized in that: the low pressure cylinder is decoupled into a separate cylinder independent arrangement structure by conventional cylinder combination arrangement, is respectively communicated with a steam exhaust pipeline of an outlet of the medium pressure cylinder, is provided with a butterfly valve on a steam exhaust main pipe of the medium pressure cylinder, is communicated with a low pressure cylinder branch of each independent separate cylinder arrangement, and is provided with a first valve on each branch;
wherein, the plurality of low-pressure cylinders have n is more than or equal to 2 cylinders;
the butterfly valve is connected with a first processor for controlling the opening of the butterfly valve, a first pressure gauge for detecting the steam pressure in the pipeline is arranged in the pipeline between the medium pressure cylinder and the butterfly valve, the first pressure gauge is connected with the first processor, the first pressure gauge sends detected steam supply pressure information to the first processor, and the first processor controls the opening of the butterfly valve according to the steam supply pressure condition measured by the first pressure gauge;
the first valves on the pipelines of the low pressure cylinders and the butterfly valves and the second valves on the pipelines of the low pressure cylinders and the condenser are respectively connected with the second processor for controlling the opening and closing of the low pressure cylinders, the second pressure gauge for detecting the steam pressure at the inlet of the low pressure cylinders is arranged in the pipelines of the low pressure cylinders and the butterfly valves, the second pressure gauge sends detected steam pressure information to the second processor, and the second processor controls the opening and closing of the first valves and the second valves respectively according to control logic.
2. A method for efficiently heating an all-condition efficient heating system of a cogeneration unit according to claim 1, wherein said method comprises:
step 1, obtaining steam supply pressure P Steam supply Low pressure cylinder inlet vapor pressure P Low pressure cylinder ；
Step 2, when the butterfly valve, the first valve and the second valve are all opened, and the steam supply pressure meets the steam supply pressure requirement, namely P Steam supply ≥P Demand for Operating according to the existing operation mode; when P Steam supply <P Demand for When the valve is in the open state, the first valves and the second valves are closed,i.e. selectively closing a plurality of low-pressure cylinders to reduce the number of low-pressure cylinders with through flow and increase the steam flow G of the remaining low-pressure cylinders with through flow g Increasing the low pressure cylinder inlet vapor pressure P Low pressure cylinder Thereby improving the steam supply pressure P Steam supply The number of the low-pressure cylinders in operation in each working condition is n, wherein the number n of the low-pressure cylinders in operation corresponds to an nth operation mode.
3. The efficient heat supply method according to claim 2, wherein the method for determining the number of the low pressure cylinders operated in each working condition in step 2 specifically includes:
a, when the butterfly valve is fully opened and the first valve and the second valve are fully opened, the steam supply pressure just meets the steam supply pressure requirement, namely P Steam supply ＝P Demand for When the corresponding total steam flow G of the low-pressure cylinder is obtained 1 Steam flow G of each low-pressure cylinder g ＝G 1/n ；
b, obtaining the total mass flow G of low-pressure cylinder through-flow steam under specific working conditions according to principle thermodynamic calculation of a thermodynamic power plant Working conditions of Dividing G into n operation modes according to different through flow numbers of the low-pressure cylinders Working conditions of Divided by the number of through-flows of the low-pressure cylinders in the n operation modes, respectively, to estimate the steam flow (G Working condition 1 ，G Working condition 2 ，G Working condition 3 ，…，G Working condition n ) Steam flow and G of each low pressure cylinder under the n operation modes g Comparing, optimizing n low-pressure cylinder operation modes by taking the highest unit energy efficiency as an optimization target, and determining the value of the low-pressure cylinder through-flow quantity m in the optimized mode, wherein m is 1-n;
wherein, the specific working condition is that under the condition that the butterfly valve, the first valve and the second valve are all opened, when P Steam supply <P Demand for When the low pressure cylinders are closed, the number of the low pressure cylinders with through flow is reduced, and the steam flow G of the remaining low pressure cylinders with through flow is increased g Increasing the low pressure cylinder inlet vapor pressure P Low pressure cylinder Thereby improving the steam supply pressure P Steam supply 。
4. A method of efficient heat supply according to claim 3 wherein the method of optimizing the n modes of operation of the low pressure cylinders in step b and determining the value of the number m of low pressure cylinder throughflows in the optimized mode comprises:
when G Working condition n ≥G g When the low-pressure cylinders are in the through-flow state, the low-pressure cylinders are in the optimal operation mode under the specific working condition, namely m=n;
when G Working condition 1 ≤G g When the low-pressure cylinder is in a through-flow state, the low-pressure cylinder is in a preferable operation mode under the specific working condition, namely m=1;
when G Working condition j ≥G g ≥G Working condition j+1 And when j=1, 2, … and n-1, performing performance evaluation on the 2 operation modes of through-flow of j low-pressure cylinders and j+1 low-pressure cylinders based on principle thermodynamic calculation of the thermodynamic power plant, and taking the operation mode with the minimum power supply standard coal consumption as a preferred mode by taking the power supply standard coal consumption as an objective function.
5. A method of efficient heat supply according to claim 2, characterized in that the method further comprises:
step 3, when the number of through-flows of the low-pressure cylinder is m, the steam supply pressure is still lower than the steam supply pressure requirement, namely P Steam supply <P Demand for The opening degree of the butterfly valve is regulated down until the steam supply pressure is equal to the steam supply demand pressure through throttling and pressure holding, P Steam supply ＝P Demand for 。
6. A method of efficient heat supply according to claim 2, characterized in that the method further comprises:
and step 4, optimizing the operation modes of all the operation working conditions of the cogeneration unit, thereby determining the corresponding relation between the low-pressure cylinder through-flow quantity and the specific working conditions in the optimized mode and obtaining the efficient heat supply/steam operation mode of the cogeneration unit under the whole working conditions.
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