CN117346202A - Heat storage structure and method of cogeneration central heating system - Google Patents

Heat storage structure and method of cogeneration central heating system Download PDF

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Publication number
CN117346202A
CN117346202A CN202311588414.6A CN202311588414A CN117346202A CN 117346202 A CN117346202 A CN 117346202A CN 202311588414 A CN202311588414 A CN 202311588414A CN 117346202 A CN117346202 A CN 117346202A
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China
Prior art keywords
primary
heat
water
pipe network
pipeline
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CN202311588414.6A
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Chinese (zh)
Inventor
邓昊
李勇
王志超
宋守勉
王淑莲
丛卫
车方港
王文豪
程小倩
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Shandong Guoneng Intelligent Technology Co ltd
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Shandong Guoneng Intelligent Technology Co ltd
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Priority to CN202311588414.6A priority Critical patent/CN117346202A/en
Publication of CN117346202A publication Critical patent/CN117346202A/en
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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
    • F24D3/00—Hot-water central heating systems
    • F24D3/02—Hot-water central heating systems with forced circulation, e.g. by pumps
    • 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
    • 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
    • F24D11/00—Central heating systems using heat accumulated in storage masses
    • F24D11/002—Central heating systems using heat accumulated in storage masses water heating system
    • F24D11/004—Central heating systems using heat accumulated in storage masses water heating system with conventional supplementary heat source
    • 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
    • F24D19/0002—Means for connecting central heating radiators to circulation pipes
    • F24D19/0004—In a one pipe system
    • 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
    • F24D19/1006—Arrangement or mounting of control or safety devices for water heating systems
    • F24D19/1009—Arrangement or mounting of control or safety devices for water heating systems for central heating
    • 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
    • F24D3/00—Hot-water central heating systems
    • F24D3/10—Feed-line arrangements, e.g. providing for heat-accumulator tanks, expansion tanks ; Hydraulic components of a central heating system
    • F24D3/1058—Feed-line arrangements, e.g. providing for heat-accumulator tanks, expansion tanks ; Hydraulic components of a central heating system disposition of pipes and pipe connections

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Heat-Pump Type And Storage Water Heaters (AREA)

Abstract

A heat storage structure and a method of a cogeneration central heating system relate to a central heating system of a thermal power plant, and comprise a heat exchange primary station, a primary heating pipe network, a secondary heat exchange station, a secondary heating pipe network and a heat user which are connected with the thermal power plant, wherein the primary side of the heat exchange primary station is connected with a steam pipeline of the thermal power plant and a condensate water recovery device, and the secondary side of the heat exchange primary station is connected with the primary heating pipe network; the primary side of the secondary heat exchange station is connected with a primary heat supply pipe network; the heat user is connected with the secondary heat supply pipe network; a primary heat storage water return valve is arranged on a primary heat supply pipe network L meters away from the heat exchange primary station; the heat storage method comprises the following steps: when the temperature rise speed of the water supply temperature of the primary heat supply pipe network is more than S, controlling the opening of the primary heat storage water return valve to be larger, and when the temperature fall speed of the water supply temperature of the primary heat supply pipe network is more than S, controlling the opening of the primary heat storage water return valve to be smaller; when the temperature rise speed or the temperature fall speed of the water supply temperature of the primary heat supply pipe network is less than or equal to S, the primary heat storage water return valve is maintained; the invention has small occupied area and small investment, and can store heat or release heat according to the needs.

Description

Heat storage structure and method of cogeneration central heating system
Technical Field
The invention relates to a central heating system of a thermal power plant, in particular to a heat storage structure and a heat storage method of a cogeneration central heating system.
Background
The central heating is a mode of heating production, heating and living heat users in a town or a large area through a heat network by taking hot water or steam generated by a central heat source as a heating medium; the central heating has the advantages of large heat load, large heat source scale, high heat efficiency, saving fuel and labor force, small occupied area and the like.
The cogeneration central heating is a main mode of urban central heating, aims at saving energy and is a recognized energy-saving and environment-friendly technology. According to statistics, in the total amount of central heat supply in the city of 2021, the heat and power cogeneration heat supply accounts for the main part, and accounts for 67% of the total central heat supply.
The existing cogeneration central heating system comprises a heat exchange primary station, a primary heat supply pipe network, a secondary heat exchange station, a secondary heat supply pipe network and a heat user, wherein the heat exchange primary station is connected with a steam pipeline of the heat power plant, a primary side outlet is connected with a condensate recovery device, and a secondary side water outlet and a water inlet of the heat exchanger in the heat exchange primary station are respectively connected with a water supply pipeline and a water return pipeline of the primary heat supply pipe network, and specifically comprises the following components: the secondary side water inlet of the heat exchanger in the heat exchange primary station is connected with a water return pipeline of the primary heat supply pipeline network through a variable frequency circulating pump, and the secondary side water outlet of the heat exchanger in the heat exchange primary station is connected with a water supply pipeline of the primary heat supply pipeline network. The primary water inlet and the water outlet of the secondary heat exchange station are respectively connected with a water supply pipeline and a water return pipeline of the primary heat supply pipe network through pipelines, the secondary water outlet and the water inlet of the secondary heat exchange station are connected with the water supply pipeline and the water return pipeline of the secondary heat supply pipe network, and the secondary water inlet of the secondary heat exchange station (an internal heat exchanger) is connected with the water return pipeline of the secondary heat supply pipe network through a variable frequency circulating pump; the heat user (indoor heat radiation equipment) is connected with the water supply pipeline and the water return pipeline of the secondary heat supply pipe network. The primary heat supply pipe network and the secondary heat supply pipe network are respectively provided with a water supply temperature sensor, a water supply pressure sensor, a heat meter, a backwater temperature sensor and a backwater pressure sensor; and the water supply flow of each stage of heat supply pipe network is controlled by the temperature data acquired by the water supply temperature sensor and the backwater temperature sensor on each stage of heat supply pipe network, so that the parallel heat supply and demand are realized.
In recent years, large thermal power units are gradually transformed to implement cogeneration central heating, and in order to improve the heat energy utilization efficiency and reduce the cold source loss, a generator is generally transformed into a low-pressure cylinder cutting type, so that the generator operates in a condensing mode in a non-heating period and operates in a back pressure mode in a heating period. The cogeneration central heating system is in two different running states of electricity by heat and electricity by heat, and the heat load and the electricity load supply and demand balance of a heat supply network and a power grid cannot be simultaneously considered.
A national grid dispatch run time interval typically includes two peak periods, two valley periods, and two normal periods a day, for example: peak period: 6:00-11:00, 18:00-23:00, for a total of 10 hours; cereal period: 1:00-6:00, 13:00-18:00 for 10 hours total; flat period: 11:00-13: 00. 23:00-1:00, for a total of 4 hours. When the power grid dispatching operation time is in a peak period, the unit needs to be operated by increasing the electric load, the steam quantity is increased, the heat is supplied more, the heat supply system cannot self-dissipate the peak regulation heat, the energy is wasted in the atmosphere, the heat storage tanks are used for storing heat, the required heat storage tanks are large in volume and large in number, the occupied area is large, and the investment is huge. When the power grid dispatching operation time is in the valley period, the unit needs to run with a power-down load, the steam quantity is reduced, the heat supply quantity is less, the heat demand of a heating system cannot be met, the phenomenon of insufficient heat source occurs, the heat-accumulating electric boiler or the natural gas boiler needs to be used for peak regulation heat supplement, and the investment is large.
Disclosure of Invention
The invention aims to solve the defects of the prior art, and provides a heat storage structure and a heat storage method of a cogeneration central heating system, which have small occupied area and small investment and can store heat or release heat according to requirements.
The invention solves the defects of the prior art, adopts the following technical proposal:
the heat storage structure of the cogeneration central heating system comprises a heat exchange primary station, a primary heat supply pipe network, a secondary heat exchange station, a secondary heat supply pipe network and a heat user, wherein the heat exchange primary station, the primary heat supply pipe network, the primary side inlet of a heat exchanger in the heat exchange primary station is connected with a steam pipeline of the heat power station, the primary side outlet of the heat exchanger in the heat exchange primary station is connected with a condensate water recovery device, the secondary side water inlet of the heat exchanger in the heat exchange primary station is connected with a water return pipeline of the primary heat supply pipe network through a primary variable frequency circulating pump and a flowmeter, and the secondary side water outlet of the heat exchanger in the heat exchange primary station is connected with a water supply pipeline of the primary heat supply pipe network; the primary water inlet and the water outlet of the heat exchanger in the secondary heat exchange station are respectively connected with a water supply pipeline and a water return pipeline of the primary heat supply pipe network through pipelines, the secondary water outlet of the heat exchanger in the secondary heat exchange station is connected with the water supply pipeline of the secondary heat supply pipe network, and the secondary water inlet of the heat exchanger in the secondary heat exchange station is connected with the water return pipeline of the secondary heat supply pipe network through a secondary variable frequency circulating pump; the heat user (indoor heat radiation equipment) is connected with a water supply pipeline and a water return pipeline of the secondary heat supply pipe network; the heat-storage water-return valve is characterized in that a primary heat-storage water-return valve L (m) is arranged between a water supply pipeline and a water return pipeline of a primary heat supply pipe network which are distant from a heat exchange primary station L meter, and the range of values of the primary heat-storage water-return valve L (m) is as follows: V.times.H Peak to peak ×3600≤L≤V×（H Peak to peak +2 H P-plane ）×3600 ，
Wherein H is Peak to peak (h) Is the duration of the peak period of the power grid, H P-plane V (m/s) is the medium flow rate in the pipeline of the primary heating pipe network for the duration of the power grid level period;
the calculation formula of V (m/s) in the invention is as follows: v= (0.354×g) Calculation of ×υ）/D 2 Wherein G is Calculation of (t/h) is the calculated flow of the first-level pipe network, v (m) 3 The specific volume of the medium water in the pipeline is shown as the ratio of/kg); d (m) is the inner diameter of a water return pipeline of the primary heat supply pipe network.
G in the invention Calculation of The formula of (t/h) is: g Calculation of = (0.86×a× q)/(T1-T2)/1000, wherein a (m) 2 ) For heating area, q (W/m) 2 ) In order to calculate the heat consumption index, T1 (DEG C) is used for calculating the water supply temperature for the primary heat supply pipe network; t2 (DEG C) is the temperature of the return water calculated by the primary heat supply pipe network.
The invention is further improved, and the calculation formula of V (m/s) is as follows: v= (0.354×g) Actual practice is that of ×υ）/D 2 ，G Actual practice is that of The actual flow of the peak period primary pipe network or the average actual flow of the peak period primary pipe network and the average period primary pipe network. General G Actual practice is that of Empirically set to 1.1G Calculation of 、1.15 G Calculation of 、1,2 G Calculation of Or 1.3G Calculation of The method comprises the steps of carrying out a first treatment on the surface of the The heat storage effect is better.
The pressure sensors and the temperature sensors are respectively arranged on the pipelines of the primary side and the secondary side of the heat exchange primary station and the secondary side of each secondary heat exchange station, and the pressure sensors and the temperature sensors are respectively arranged on the water supply pipeline and the water return pipeline of the primary heat supply pipeline network and the water return pipeline of the front side and the rear side of the primary heat storage water return valve and are used for monitoring heat supply data of each place of the heat supply system in real time.
The water supply pipeline of the primary heat supply pipe network comprises a water supply main pipeline and a water supply branch pipeline, and the backwater main pipeline comprises a backwater main pipeline and a backwater branch pipeline; the water supply branch pipeline and the backwater branch pipeline are used for connecting the primary side of the heat exchanger in the secondary heat exchange station with the main water supply pipeline and the main backwater pipeline; the primary heat storage water return valve is arranged between the main water supply pipeline and the main water return pipeline.
According to the invention, the water supply pipeline of the primary heat supply pipe network comprises a water supply main pipeline and a water supply branch pipeline, and the water return main pipeline comprises a water return main pipeline and a water return branch pipeline; the primary water inlet and the primary water outlet of the heat exchanger in the secondary heat exchange station are respectively connected with the main water supply pipeline and the main water return pipeline through the water supply branch pipeline and the main water return pipeline; the primary heat storage water return valve is arranged between a water supply branch pipeline and a water return branch pipeline in the secondary heat exchange station, and primary heat storage water return valves are respectively arranged between the water supply branch pipelines and the water return branch pipelines in the n secondary heat exchange stations within the range of L meters from the heat exchange primary station. The structure can be constructed in the secondary heat exchange station, is convenient for the installation and control of the primary heat storage water return valve, is simple and easy to operate, has low cost, can control one or more primary heat storage water return valves to be opened when the peak regulation flow changes less, and has high flow control precision.
The invention is further improved, and a secondary heat storage water return valve is arranged at the rear parts of a water supply pipeline and a water return pipeline of the secondary heat supply pipe network. The high temperature water in the water supply pipeline of the secondary heat supply pipe network can flow back to the secondary water inlet of the heat exchanger in the secondary heat exchange station through the secondary heat storage water return valve and the water return pipeline to carry out secondary heat storage.
The heat storage method of the cogeneration central heating system is characterized by comprising the following steps of:
controlling the opening degree of the first-stage heat storage water return valve to be larger when the temperature rise speed of the water supply temperature of the first-stage heat supply pipe network is larger than S, so that the temperature rise speed of the water supply temperature of the first-stage heat supply pipe network is smaller than or equal to S;
controlling the opening of the primary heat storage water return valve to be smaller when the temperature drop speed of the water supply temperature of the primary heat supply pipe network is more than S, so that the temperature drop speed of the water supply temperature of the primary heat supply pipe network is less than or equal to S;
step three, when the temperature rise speed or the temperature fall speed of the water supply temperature of the primary heat supply pipe network is detected to be less than or equal to S, the primary heat storage water return valve is maintained;
in the first-stage heat storage water return valve adjusting process, when three boundary conditions t3=t4 and delta P are met J =ΔP Minimum of 、G1 Operation =G1 Maximum value When the first-stage heat storage water return valve reaches the allowable maximum opening degree;
wherein: s is the maximum lifting speed allowed by the water supply temperature of a primary heat supply pipe network at the outlet of the secondary side of a heat exchanger in a heat exchange primary station;
ΔP J the pressure difference value of the primary side water supply and return pipeline of the heat exchanger in the secondary heat exchange station is the most unfavorable point.
ΔP Minimum of The minimum differential pressure value of the primary side water supply and return pipeline of the heat exchanger in the secondary heat exchange station is obtained;
G1 operation The flow rate of the primary heat supply pipe network is t/h, and a flowmeter is arranged at the secondary side of the heat exchanger in the heat exchange primary station for acquisition.
G1 Maximum value The unit is t/h, which is the maximum flow conveying capacity of the primary heat supply pipe network.
t3 (DEG C) is the return water temperature of the heat storage post-stage heat supply pipe network, and is the temperature after the water supply pipeline of the primary heat supply pipe network is partially mixed with the return water pipeline of the primary heat supply pipe network after the primary heat storage return water valve is opened;
t4 is the return line safety boundary temperature.
In the invention, when the primary heat storage water return valve is arranged between a water supply branch pipe and a water return branch pipe in the secondary heat exchange station, a primary heat storage water return valve (n primary heat storage water return valves in total) is respectively arranged between the water supply branch pipe and the water return branch pipe in n secondary heat exchange stations (each secondary heat exchange station in the range of a heat exchange primary station L (m); in the heat storage method of the cogeneration central heating system, in the process of adjusting (opening is enlarged and reduced) the (n) first-stage heat storage water return valves, (the automatic control system can judge in real time) when the ith first-stage heat storage water return valve meets three boundary conditions t3=t4 and deltaP iJ =ΔP Minimum of 、G i 1 Operation =G i 1 Maximum value In any condition, the ith first-stage heat storage water return valve reaches the allowable maximum opening (the opening can not be continuously increased, if t3 is more than t4 and delta P appear iJ ＜ΔP Minimum of 、G i 1 Operation ＞G i 1 Maximum value When the ith one is to be controlledThe opening degree of the stage heat storage water return valve is reduced by 3 percent);
ΔP iJ the pressure difference value of the primary side water supply and return pipeline of the heat exchanger in the secondary heat exchange station is the most unfavorable point.
ΔP Minimum of The minimum differential pressure value of the primary side water supply and return pipeline of the heat exchanger in the secondary heat exchange station is obtained;
G i 1 operation The unit is t/h for the operation flow of the primary heat supply pipe network;
G i 1 maximum value The maximum flow conveying capacity of the primary heat supply pipe network is given by the unit of t/h;
t3 (DEG C) is the return water temperature of the heat storage post-stage heat supply pipe network, and is the temperature after the water supply pipeline of the primary heat supply pipe network is partially mixed with the return water pipeline of the primary heat supply pipe network after the primary heat storage return water valve is opened;
t4 is the return line safety boundary temperature.
When the primary heat storage water return valve reaches the maximum allowable opening degree in the working process, and the temperature rise speed of the water supply temperature of the primary heat supply pipe network is more than S, the primary side flow of the heat exchange primary station is controlled.
In the invention, n first-stage heat storage water return valves can be controlled to be opened or closed simultaneously, and also can be controlled to be opened or closed sequentially; preferably: when the temperature rise speed of the water supply temperature of the primary heat supply pipe network is more than S, a first one or a first group of primary heat storage water return valves closest to the heat exchange primary station are controlled to be opened, and when the temperature rise speed of the water supply temperature of the primary heat supply pipe network is more than S after the first one or the first group of primary heat storage water return valves reach the allowable maximum opening, a second one or a second group of primary heat storage water return valves at the rear side of the first one or the first group of primary heat storage water return valves are controlled to be opened, and the primary heat storage water return valves are controlled to be opened in sequence according to the distance from the heat exchange primary station from near to far. When the temperature drop speed of the water supply temperature of the primary heat supply pipe network is more than S, the last one or a group of primary heat storage water return valves which are farthest from the heat exchange primary station are controlled to be closed firstly, and when the temperature drop speed of the water supply temperature of the primary heat supply pipe network is more than S after the last one or a group of primary heat storage water return valves are completely closed, one or a group of primary heat storage water return valves on the front side of the last one or a group of primary heat storage water return valves are controlled to be closed, and the primary heat storage water return valves are controlled to be closed in sequence according to the distance from the heat exchange primary station from the far to the near.
According to the invention, when the temperature rise speed of the water supply temperature of the primary heat supply pipe network at the secondary side outlet of the heat exchanger in the heat exchange primary station is still more than S after the primary heat storage water return valve reaches the allowable maximum opening degree in the peak period, the secondary heat storage water return valve is controlled to be opened, and high-temperature water in the water supply pipeline of the secondary heat supply pipe network enters the water return pipeline of the secondary heat supply pipe network to form high-temperature water return, so that the heat storage of the secondary heat supply pipe network is realized. The flow in the secondary heat supply pipe network is gradually increased, the opening of a primary side electric regulating valve of the secondary heat exchange station is controlled to be increased, and the flow of the primary side is synchronously increased; and controlling the operation frequency of the secondary variable frequency circulating pump to be synchronously improved. In the frequency conversion process of the two-stage frequency conversion circulating pump, two boundary conditions are satisfied simultaneously: hold G2 Operation ≤G2 Maximum value Maintaining constant pressure difference delta P2 (m) at the secondary side and the outlet of the heat exchanger in the secondary station to operate; when the temperature drop speed of the water supply temperature of the primary heat supply pipe network is more than S in the valley period, firstly, the secondary heat storage water return valve is controlled to be closed, so that the flow rate of the secondary heat supply pipe network is reduced, the operation frequency of the secondary variable frequency circulating pump is synchronously reduced, the constant pressure difference delta P2 (m) at the secondary side and the outlet of the heat exchanger in the secondary station is kept to operate, the high-temperature water return is operated to the secondary side water inlet of the heat exchanger in the secondary heat exchange station, and the water supply pipeline of the secondary heat supply pipe network can be reached to a preset temperature after a small amount of heat is absorbed in the secondary heat exchange station, so that the heat consumption requirement of a user is met; when the temperature drop speed of the water supply temperature of the primary heat supply pipe network is more than S after the secondary heat storage water return valve is completely closed, the primary heat storage water return valve is closed.
Δp2 is the differential pressure value at the secondary side and outlet of the heat exchanger in the secondary heat exchange station;
G2 operation The flow is the running flow of the secondary heat supply pipe network;
G2 maximum value The maximum flow conveying capacity of the secondary heat supply pipe network is provided;
in the opening process of the primary heat storage water return valve, the flow in the primary heat supply pipe network is gradually increased, and the increased flow value is the flow of the primary heat storage water return valve, so thatThe running resistance loss of the water supply and return pipeline of the primary heating pipe network is gradually increased, and the running frequency of the primary variable frequency circulating pump of the first station is synchronously and gradually increased through an automatic control system. In the water pump frequency conversion process, two boundary conditions are satisfied simultaneously: hold G1 Operation ≤G1 Maximum value And keeping constant pressure difference delta P1 (m) at the secondary side and the outlet of the heat exchanger in the heat exchange primary station.
Δp1 is the differential pressure value at the secondary side and outlet of the heat exchanger in the heat exchange primary station;
G1 operation The operation flow of the primary heat supply pipe network is provided;
G1 maximum value The maximum flow conveying capacity of the primary heat supply pipe network is provided;
the primary heat storage water return valve can synchronously regulate and control operation through a PLC (automatic control system) of the automatic control system. The heat accumulating water return valve regulating and controlling method adopts time and opening proportion method, monitors relevant operation parameters in real time through an automatic control system, and step-by-step controls the opening of the communication electric regulating valve through an edge calculation and fuzzy control mode by selecting a principle that the opening of the valve is 3% at 2 seconds intervals (the automatic control program can modify the time and the opening proportion).
The heat storage structure and the method can enable excessive heat generated when the power grid dispatching operation time is in a peak period to be accumulated in the water return pipeline of the central heating system, and timely supplement the heat accumulated in the water return pipeline of the central heating system to the water supply pipeline of the central heating system when the power grid dispatching operation time is in a valley period and the heat generated by the power grid dispatching operation time is insufficient; compared with the prior art, the device has the advantages of simple structure, convenient operation, small occupied area, low investment and the like.
Drawings
Fig. 1 is a schematic structural view of embodiment 1 in the present invention.
Fig. 2 is a schematic structural view of embodiment 2 in the present invention.
FIG. 3 is a schematic view showing the structure of example 1 of the present invention connected to a thermal power plant.
Detailed Description
Example 1
Cogeneration central heating system as shown in fig. 1The heat storage structure comprises a heat exchange primary station 2, a primary heat supply pipe network, a secondary heat exchange station 10, a secondary heat supply pipe network and a heat user 12, wherein the primary side inlet of a heat exchanger in the heat exchange primary station 2 is connected with a steam output pipeline 1 of the heat power plant, the primary side outlet of the heat exchanger is connected with a condensate water recovery device, the condensate water recovery device can be a water tank and a water storage tank, the secondary side water inlet of the heat exchanger in the heat exchange primary station 2 is connected with a water return pipeline 9 of the primary heat supply pipe network through a primary variable frequency circulating pump 3 and a flowmeter 6, and the secondary side water outlet of the heat exchanger in the heat exchange primary station 2 is connected with a water supply pipeline 7 of the primary heat supply pipe network; the primary water inlet and the water outlet of the heat exchanger in the secondary heat exchange station 10 are respectively connected with a water supply pipeline 2 and a water return pipeline 9 of the primary heat supply pipe network through pipelines, the secondary water outlet of the heat exchanger in the secondary heat exchange station 10 is connected with the water supply pipeline of the secondary heat supply pipe network, and the secondary water inlet of the heat exchanger in the secondary heat exchange station 10 is connected with a water return pipeline 11 of the secondary heat supply pipe network through a secondary variable frequency circulating pump; the indoor heat radiation equipment of the heat user 12 is connected with the water supply pipeline and the water return pipeline 11 of the secondary heat supply pipeline. The water supply pipeline of the primary heat supply pipe network at the front side of the primary heat storage water return valve is provided with a pressure sensor and a temperature sensor respectively, the water return pipeline is provided with a pressure sensor and a temperature sensor respectively, and the water supply pipeline of the primary heat supply pipe network at the rear side of the primary heat storage water return valve is provided with a pressure sensor and a temperature sensor respectively; the pressure sensor 5 and the temperature sensor 4 are respectively arranged on the pipelines of the primary side and the secondary side of the heat exchange primary station 2 and each secondary heat exchange station, namely, the pressure sensor and the temperature sensor are arranged on the water inlet pipeline connected with the steam output pipeline 1 of the thermal power plant on the primary side of the heat exchange primary station, the pressure sensor and the temperature sensor are arranged on the water outlet pipeline connected with the condensate water recovery device on the primary side of the heat exchanger in the heat exchange primary station 2, the pressure sensor 5 and the temperature sensor 4 are arranged on the water supply pipeline of the primary heat supply pipeline of the secondary side of the heat exchanger in the heat exchange primary station 2, the pressure sensor and the temperature sensor are arranged on the water return pipeline of the primary heat supply pipeline connected with the primary heat supply pipeline on the primary side of each secondary heat exchange stationThe pressure sensor and the temperature sensor are arranged on a pipeline, the primary side of each secondary heat exchange station is connected with the water return pipeline of the primary heat supply pipe network, the pressure sensor and the temperature sensor are arranged on a pipeline, the secondary side of each secondary heat exchange station is connected with the water supply pipeline of the secondary heat supply pipe network, and the pressure sensor and the temperature sensor are arranged on a pipeline, the secondary side of each secondary heat exchange station is connected with the water return pipeline of the secondary heat supply pipe network; the pressure sensor and the temperature sensor can be arranged independently or can be an integrated remote monitor; the above structure is the same as the prior art and will not be described again. The invention is characterized in that: a primary heat storage water return valve 8 is arranged between a water supply pipeline 7 and a water return pipeline 9 of a primary heat supply pipe network which is L meters away from a heat exchange primary station; as can be seen from fig. 1, the water supply pipeline of the primary heat supply pipe network comprises a water supply main pipeline and a water supply branch pipeline, and the water return main pipeline comprises a water return main pipeline and a water return branch pipeline; the water supply branch pipeline and the backwater branch pipeline are used for connecting the primary side of the heat exchanger in the secondary heat exchange station with the main water supply pipeline and the main backwater pipeline; the primary heat storage water return valve 8 is arranged between the main water supply pipeline and the main water return pipeline. L is the length of main water supply pipeline or return water trunk line, and the water inlet end and the water outlet end of one-level heat accumulation return valve 8 link to each other with one-level heating network main water supply pipeline 7 and return water trunk line 9 respectively, L's unit be the rice, take the value scope as: V.times.H Peak to peak ×3600≤L≤V×（H Peak to peak +2 H P-plane ) X 3600, typically select V.times.H Peak to peak ×3600≤L≤V×（H Peak to peak + H P-plane ) X 3600; wherein H is Peak to peak (h) Is the duration of the peak period (one) of the power grid, H P-plane V (m/s) is the medium flow rate in the water return pipeline of the primary heating pipe network for the duration of the (one) flat period of the power grid;
the calculation formula of V (m/s) is as follows: v= (0.354×g) Calculation of ×υ）/D 2 ，
Wherein G is Calculation of (t/h) calculating the flow of the primary pipe network; v (m) 3 Kg) is the specific volume of the medium water in the pipeline; d (m) is the inner diameter of a (backwater) pipeline of the primary heat supply pipe network. The G is Calculation of (t/h)The calculation formula is as follows: g Calculation of = (0.86×a×q)/(T1-T2)/1000; wherein A (m 2 ) Is a heating area; q (W/m) 2 ) To calculate the heat consumption index; t1 (DEG C) is the temperature of the water supply calculated by the primary heat supply pipe network; t2 (DEG C) is the temperature of the return water calculated by the primary heat supply pipe network.
The formula of V (m/s) is preferably: v= (0.354×g) Actual practice is that of ×υ）/D 2 ，G Actual practice is that of The method is the actual flow of the peak period primary pipe network, the peak period and the average actual flow of the average period primary pipe network. General G Actual practice is that of Empirically set to 1.1G Calculation of 、1.15 G Calculation of 、1,2 G Calculation of Or 1.3G Calculation of The method comprises the steps of carrying out a first treatment on the surface of the The heat storage effect is better.
The heat storage method of the cogeneration central heating system of the embodiment comprises the following steps:
when the temperature rise speed (the temperature rise speed) of the water supply temperature of the primary heat supply pipe network (which is usually detected in real time by installing a temperature sensor on a pipeline at the secondary side water outlet of a heat exchanger in a heat exchange primary station) is more than S, the automatic control system controls the opening degree of a primary heat storage water return valve to be increased, so that the temperature rise speed of the water supply temperature of the primary heat supply pipe network is less than or equal to S; the high-temperature hot water part in the water supply pipeline of the primary heat supply pipe network enters the water return pipeline to store heat to form high-temperature backwater, so that the heat storage of the primary heat supply pipe network is realized;
when the temperature drop speed (temperature drop speed) of the water supply temperature of the primary heat supply pipe network is more than S, the automatic control system controls the opening of the primary heat storage water return valve to be smaller, so that the temperature drop speed of the water supply temperature of the primary heat supply pipe network is less than or equal to S;
step three, when the temperature rise speed or the temperature fall speed of the water supply temperature of the primary heat supply pipe network is detected to be less than or equal to S, the opening of the primary heat storage water return valve is kept unchanged;
in the process of regulating the primary heat storage water return valve (the opening degree is increased and decreased), the automatic control system can judge in real time, and when three boundary conditions t3=t4 and deltaP are met J =ΔP Minimum of 、G1 Operation =G1 Maximum value When the first-stage heat storage water return valve reaches the allowable maximum opening degree under any condition, the opening degree can not be continuously increased, for exampleAppear t3 > t4, deltaP J ＜ΔP Minimum of 、G1 Operation ＞G1 Maximum value When the opening degree of the primary heat storage water return valve needs to be controlled to be 10 percent smaller;
wherein: s is the maximum lifting speed allowed by the water supply temperature of a primary heat supply pipe network at the outlet of the secondary side of a heat exchanger in a heat exchange primary station, wherein the unit is ℃/h, and generally 4-6 ℃/h is taken;
ΔP J the pressure difference value of a primary side water supply and return pipeline of a heat exchanger in a secondary heat exchange station with the least adverse point (the rear side of a primary heat storage water return valve and the farthest distance from the primary heat storage water return valve); ΔP J =P J 1-P J 2，P J 1 is the primary side operation water supply pressure P of the heat exchanger in the secondary heat exchange station with the least adverse point J 2 is the primary side operation backwater pressure of the heat exchanger in the secondary heat exchange station at the most unfavorable point; and respectively installing pressure sensors at a primary water inlet and a water return inlet of a heat exchanger in the secondary heat exchange station at the most unfavorable point for acquisition.
ΔP Minimum of The minimum differential pressure value of the primary side water supply and return pipeline of the heat exchanger in the secondary heat exchange station is obtained; the unit is m, which is a set value, and is conventionally selected from 8 to 12, preferably 10 to 11;
G1 operation The flow rate of the primary heat supply pipe network is t/h, and a flowmeter is arranged at the position of a secondary water inlet of a heat exchanger in a heat exchange primary station;
G1 maximum value The maximum flow conveying capacity of the primary heat supply pipe network is given by the unit of t/h; obtaining a first-stage pipe network hydraulic calculation result;
t3 (DEG C) is the return water temperature of the heat storage post-stage heat supply pipe network, a temperature sensor is arranged on the return water pipeline at the front side of the primary heat storage return valve for remote acquisition, and the return water temperature is the temperature after the water supply pipeline of the primary heat supply pipe network is partially mixed with the return water pipeline of the primary heat supply pipe network after the primary heat storage return valve is opened;
t4 is the safety boundary temperature of the return water pipeline at the installation position of the primary heat storage return valve, namely the allowable highest temperature, and the unit is the temperature, and generally 70-80 ℃.
Example 2
The heat storage structure of the cogeneration central heating system shown in fig. 2 comprises a heat storage structure which is matched with a thermal power plantThe system comprises a heat exchange primary station 2, a primary heat supply pipe network, a secondary heat exchange station 10, a secondary heat supply pipe network and a heat user 12 which are connected, wherein a primary side inlet of a heat exchanger in the heat exchange primary station 2 is connected with a steam output pipeline 1 of a thermal power plant, a primary side outlet of the heat exchanger is connected with a condensate water recovery device, the condensate water recovery device is a reservoir, a secondary side inlet of the heat exchanger in the heat exchange primary station 2 is connected with a water return pipeline 9 of the primary heat supply pipe network through a primary variable frequency circulating pump 3 and a flowmeter 6, and a secondary side water outlet of the heat exchanger in the heat exchange primary station 2 is connected with a water supply pipeline 7 of the primary heat supply pipe network; the primary water inlet and the water outlet of the heat exchanger in the secondary heat exchange station 10 are respectively connected with a water supply pipeline 2 and a water return pipeline 9 of the primary heat supply pipe network through pipelines, the secondary water outlet of the heat exchanger in the secondary heat exchange station 10 is connected with the water supply pipeline of the secondary heat supply pipe network, and the secondary water inlet of the heat exchanger in the secondary heat exchange station 10 is connected with a water return pipeline 11 of the secondary heat supply pipe network through a secondary variable frequency circulating pump; the indoor heat dissipation equipment of the heat user 12 is connected with a water supply pipeline and a water return pipeline 11 of the secondary heat supply pipe network; the pressure sensor 5 and the temperature sensor 4 are respectively arranged on the pipelines of the primary side and the secondary side of the heat exchange primary station 2 and each secondary heat exchange station; the pressure sensor and the temperature sensor can be independently arranged or can be an integrated remote transmission monitor; the above structure is the same as the prior art and will not be described again. The invention is characterized in that: a primary heat storage water return valve is arranged between a water supply pipeline 7 and a water return pipeline 9 of a primary heat supply pipe network which are L meters away from a heat exchange primary station; as can be seen from fig. 2, the water supply pipeline of the primary heat supply pipe network comprises a water supply main pipeline and a water supply branch pipeline 13, and the backwater main pipeline comprises a backwater main pipeline and a backwater branch pipeline 14; the water supply branch pipe 13 and the backwater branch pipe 14 are used for connecting the primary side of the heat exchanger in the secondary heat exchange station with the main water supply pipe and the main backwater pipe; the primary heat storage water return valve 15 is arranged between the water supply branch pipe 13 and the water return branch pipe 14 in front of the secondary heat exchange station 10 (water in the water supply pipe flows from front to back). L is the sum of the lengths of the main water supply pipeline and the branch water supply pipeline or the sum of the lengths of the main water return pipeline and the branch water return pipeline, and the water supply pipelineThe length and the length of the return line are typically equal. The water inlet end and the water outlet end of the primary heat storage water return valve 15 are respectively connected with the water supply branch pipeline 13 and the water return branch pipeline 14 of the primary heat supply pipe network, the unit of L is rice, and the value range is as follows: V.times.H Peak to peak ×3600≤L≤V×（H Peak to peak +2 H P-plane ) X 3600, typically select V.times.H Peak to peak ×3600≤L≤V×（H Peak to peak + H P-plane ) X 3600; wherein H is Peak to peak (h) Is the duration of the peak period (one) of the power grid, H P-plane V (m/s) is the medium flow rate in the water return pipeline of the primary heating pipe network for the duration of the (one) flat period of the power grid; the primary water inlet and the primary water outlet of the heat exchanger in the secondary heat exchange station 10 are respectively connected with the main water supply pipeline 7 and the main water return pipeline 9 through the water supply branch pipeline 13 and the main water return pipeline 14; the primary heat storage water return valve is arranged between a water supply branch pipeline and a water return branch pipeline in the secondary heat exchange station, and primary heat storage water return valves 15 (n primary heat storage water return valves 15) are respectively arranged between the water supply branch pipelines and the water return branch pipelines in the n secondary heat exchange stations after the primary heat exchange station L (m). The structure can be constructed in the secondary heat exchange station, is convenient for the installation and control of the primary heat storage water return valve, is simple and easy to operate, has low cost, can control one or more primary heat storage water return valves to be opened when the peak regulation flow changes less, and has high flow control precision. Each pair of (3)
The invention is further improved, a secondary heat storage water return valve 16 is arranged at the rear part (tail end) of a water supply pipeline and a water return pipeline of the secondary heat supply pipeline, and the water inlet end and the water outlet end of the secondary heat storage water return valve 16 are respectively connected with the water supply pipeline and the water return pipeline of the secondary heat supply pipeline. The high temperature water in the water supply pipeline of the secondary heat supply pipe network can flow back to the secondary water inlet of the heat exchanger in the secondary heat exchange station through the secondary heat storage water return valve and the water return pipeline to carry out secondary heat storage.
In the embodiment, a first-stage heat storage water return valve is respectively arranged between a water supply branch pipeline and a water return branch pipeline in each of n secondary heat exchange stations within a range of L (m) from a heat exchange primary station, and n first-stage heat storage water return valves are altogether arranged;
the heat storage method of the cogeneration central heating system of the embodiment comprises the following steps:
when the temperature rise speed of the water supply temperature of the primary heat supply pipe network is more than S, the opening of the primary heat storage water return valve is controlled to be larger by the automatic control system, so that the temperature rise speed of the water supply temperature of the primary heat supply pipe network is less than or equal to S; the high-temperature hot water part in the water supply pipeline of the primary heat supply pipe network enters the water return pipeline to store heat to form high-temperature backwater, so that the heat storage of the primary heat supply pipe network is realized;
when the temperature drop speed of the water supply temperature of the primary heat supply pipe network is more than S, the automatic control system controls the opening of the primary heat storage water return valve to be smaller, so that the temperature drop speed of the water supply temperature of the primary heat supply pipe network is less than or equal to S;
step three, when the temperature rise speed or the temperature fall speed of the water supply temperature of the primary heat supply pipe network is detected to be less than or equal to S, the opening of the primary heat storage water return valve is kept unchanged;
in the regulating process of the primary heat storage water return valve, the automatic control system carries out real-time distinguishing control, and when three boundary conditions t3=t4 and deltaP are met J =ΔP Minimum of 、G1 Operation =G1 Maximum value When the first-stage heat storage water return valve reaches the allowable maximum opening degree under any condition, the opening degree can not be continuously increased, if t3 is more than t4 and delta P appear J ＜ΔP Minimum of 、G1 Operation ＞G1 Maximum value When the opening degree of the primary heat storage water return valve needs to be controlled to be 10 percent smaller;
wherein: s is the maximum lifting speed allowed by the water supply temperature of a primary heat supply pipe network at the outlet of the secondary side of a heat exchanger in a heat exchange primary station, wherein the unit is ℃/h, and generally 4-6 ℃/h is taken;
in the regulation process of n first-stage heat-storage water return valves, an automatic control system can perform real-time discrimination control, and when the ith first-stage heat-storage water return valve meets three boundary conditions t3=t4 and deltaP iJ =ΔP Minimum of 、G i 1 Operation =G i 1 Maximum value When the ith first-stage heat storage water return valve reaches the allowable maximum opening degree, the opening degree cannot be increased continuously; if t3 > t4, deltaP appears iJ ＜ΔP Minimum of 、G i 1 Operation ＞G i 1 Maximum value When the opening degree of the ith first-stage heat storage water return valve is required to be controlled to be 3 percent smaller;
ΔP iJ is the pressure difference value delta P of the primary side water supply and return pipeline of the heat exchanger in the secondary heat exchange station with the least adverse point iJ =P iJ 1-P iJ 2，P iJ 1 is the primary side operation water supply pressure P of the heat exchanger in the secondary heat exchange station with the least adverse point iJ 2 is the primary side operation backwater pressure of the heat exchanger in the secondary heat exchange station at the most unfavorable point; and respectively installing pressure sensors at a primary water inlet and a water return inlet of a heat exchanger in the secondary heat exchange station at the most unfavorable point for acquisition.
ΔP Minimum of The minimum differential pressure value of the primary side water supply and return pipeline of the heat exchanger in the secondary heat exchange station is obtained; the unit is m, which is a set value, and is conventionally selected from 8 to 12, preferably 10 to 11;
G i 1 operation The method comprises the steps that a flowmeter is installed at a secondary side outlet of a heat exchanger in a heat exchange primary station to acquire the operation flow of a primary heat supply pipe network, wherein the unit is t/h;
G i 1 maximum value The maximum flow conveying capacity of the primary heat supply pipe network is t/h, and is obtained from the hydraulic calculation result of the primary pipe network;
t3 (DEG C) is the return water temperature of the heat storage post-stage heat supply pipe network, a temperature sensor is arranged on the return water pipeline at the front side of the primary heat storage return valve for remote acquisition, and the return water temperature is the temperature after the water supply pipeline of the primary heat supply pipe network is partially mixed with the return water pipeline of the primary heat supply pipe network after the primary heat storage return valve is opened;
t4 is the safety boundary temperature of the return water pipeline at the installation position of the primary heat storage return valve, namely the allowable highest temperature, and the unit is the temperature, and generally 70-80 ℃.
In the embodiment, n first-stage heat storage water return valves can be controlled to be opened or closed simultaneously, and also can be controlled to be opened or closed sequentially; preferably: when the temperature rise speed of the water supply temperature of the primary heat supply pipe network is more than S, a first one or a first group of primary heat storage water return valves closest to the heat exchange primary station are controlled to be opened, and when the temperature rise speed of the water supply temperature of the primary heat supply pipe network is more than S after the first one or the first group of primary heat storage water return valves reach the allowable maximum opening, a second one or a second group of primary heat storage water return valves at the rear side of the first one or the first group of primary heat storage water return valves are controlled to be opened, and the primary heat storage water return valves are controlled to be opened in sequence according to the distance from the heat exchange primary station from near to far. When the temperature drop speed of the water supply temperature of the primary heat supply pipe network is more than S, the last one or a group of primary heat storage water return valves which are farthest from the heat exchange primary station are controlled to be closed firstly, and when the temperature drop speed of the water supply temperature of the primary heat supply pipe network is more than S after the last one or a group of primary heat storage water return valves are completely closed, one or a group of primary heat storage water return valves on the front side of the last one or a group of primary heat storage water return valves are controlled to be closed, and the primary heat storage water return valves are controlled to be closed in sequence according to the distance from the heat exchange primary station from the far to the near.
According to the invention, when the temperature rise speed of the water supply temperature of the primary heat supply pipe network at the secondary side outlet of the heat exchanger in the heat exchange primary station is still more than S after the primary heat storage water return valve (all) reaches the allowable maximum opening degree in the peak period, the automatic control system controls the secondary heat storage water return valve to be opened, and high-temperature water in the water supply pipeline of the secondary heat supply pipe network enters the water return pipeline of the secondary heat supply pipe network to form high-temperature water return, so that the heat storage of the secondary heat supply pipe network is realized. The flow in the secondary heat supply pipe network is gradually increased, and an automatic control system can control the opening of a primary side electric regulating valve of the secondary heat exchange station to be increased and the flow of the primary side to be synchronously increased; and the automatic control system controls the operation frequency of the secondary variable frequency circulating pump to be synchronously improved. In the frequency conversion process of the two-stage frequency conversion circulating pump, two boundary conditions are satisfied simultaneously: hold G2 Operation ≤G2 Maximum value Maintaining constant pressure difference delta P2 (m) at the secondary side and the outlet of the heat exchanger in the secondary station to operate; when the temperature drop speed of the water supply temperature of the primary heat supply pipe network is more than S in the valley period, firstly, the automatic control system controls the secondary heat storage water return valve to be closed firstly, so that the flow rate in the secondary heat supply pipe network is reduced, the operation frequency of the secondary variable frequency circulating pump is controlled by the automatic control system to be synchronously reduced, the constant pressure difference delta P2 (m) at the secondary side and the outlet of the heat exchanger in the secondary station is kept to operate, the high-temperature water return operation is carried out to the secondary side water inlet of the heat exchanger in the secondary heat exchange station, and the water supply pipeline of the secondary heat supply pipe network can be reached to a preset temperature after a small amount of heat is absorbed in the secondary heat exchange station, so that the heat consumption requirement of users is met; when the temperature drop speed of the water supply temperature of the primary heat supply pipe network is more than S after the secondary heat storage water return valve is completely closed, controlling one of the water supply valvesAnd closing the stage heat storage water return valve.
Δp2 is the differential pressure value at the secondary side and outlet of the heat exchanger in the secondary heat exchange station, and the unit is m;
and G2 is the running flow of the secondary heat supply pipe network, the unit is t/h, and the flow is acquired by installing a flowmeter on the secondary side outlet pipeline of the heat exchanger in the secondary station.
G2 Maximum value The unit is t/h, and the maximum flow conveying capacity of the secondary heat supply pipe network is obtained by the hydraulic calculation result of the secondary pipe network.
In the opening process of the primary heat storage water return valve, the flow in the primary heat supply pipe network is gradually increased, the increased flow value is the flow of the primary heat storage water return valve, so that the running resistance loss of the water supply and return pipeline of the primary heat supply pipe network is gradually increased, and the running frequency of the primary variable frequency circulating pump of the first station is synchronously and gradually increased through an automatic control system. In the water pump frequency conversion process, two boundary conditions are satisfied simultaneously: hold G1 Operation ≤G1 Maximum value And keeping constant pressure difference delta P1 (m) at the secondary side and the outlet of the heat exchanger in the heat exchange primary station.
Δp1 is the differential pressure value (in m) at the secondary side and outlet of the heat exchanger in the heat exchange primary station;
G1 operation The heat exchange system is characterized in that the heat exchange system is obtained by installing a heat meter at the outlet of the secondary side of a heat exchanger in a heat exchange primary station for collecting the operation flow of a primary heat supply pipe network, wherein the unit is t/h.
G1 Maximum value The maximum flow conveying capacity of the primary heat supply pipe network is t/h, and is obtained from the hydraulic calculation result of the primary pipe network.
The heat storage water return valve can synchronously regulate and control operation through the PLC of the automatic control system. The heat accumulating water return valve regulating and controlling method adopts time and opening proportion method, monitors relevant operation parameters in real time through an automatic control system, selects the principle of 3% of valve opening at 2 seconds time interval through edge calculation and fuzzy control mode, and the automatic control program can modify the time and opening proportion and control the opening of the communication electric regulating valve step by step.
The heat storage structure and the method can enable excessive heat generated when the power grid dispatching operation time is in a peak period to be accumulated in the water return pipeline of the central heating system, and timely supplement the heat accumulated in the water return pipeline of the central heating system to the water supply pipeline of the central heating system when the power grid dispatching operation time is in a valley period and the heat generated by the power grid dispatching operation time is insufficient; compared with the prior art, the device has the advantages of simple structure, convenient operation, small occupied area, low investment and the like.

Claims (9)

1. The heat storage structure of the cogeneration central heating system comprises a heat exchange primary station, a primary heat supply pipe network, a secondary heat exchange station, a secondary heat supply pipe network and a heat user, wherein the heat exchange primary station, the primary heat supply pipe network, the primary side inlet of a heat exchanger in the heat exchange primary station is connected with a steam pipeline of the heat power station, the primary side outlet of the heat exchanger in the heat exchange primary station is connected with a condensate water recovery device, the secondary side water inlet of the heat exchanger in the heat exchange primary station is connected with a water return pipeline of the primary heat supply pipe network through a primary variable frequency circulating pump and a flowmeter, and the secondary side water outlet of the heat exchanger in the heat exchange primary station is connected with a water supply pipeline of the primary heat supply pipe network; the primary water inlet and the water outlet of the heat exchanger in the secondary heat exchange station are respectively connected with a water supply pipeline and a water return pipeline of the primary heat supply pipe network through pipelines, the secondary water outlet of the heat exchanger in the secondary heat exchange station is connected with the water supply pipeline of the secondary heat supply pipe network, and the secondary water inlet of the heat exchanger in the secondary heat exchange station is connected with the water return pipeline of the secondary heat supply pipe network through a secondary variable frequency circulating pump; the heat user (indoor heat radiation equipment) is connected with a water supply pipeline and a water return pipeline of the secondary heat supply pipe network; the heat-storage water-return valve is characterized in that a primary heat-storage water-return valve is arranged between a water supply pipeline and a water return pipeline of a primary heat supply pipe network which are distant from a heat exchange primary station L meter, and the value range of L (m) is as follows: V.times.H Peak to peak ×3600≤L≤V×（H Peak to peak +2 H P-plane ) X 3600, where H Peak to peak (h) Is the duration of the peak period of the power grid, H P-plane V (m/s) is the medium flow velocity in the pipeline of the primary heating pipe network for the duration of the grid level period.
2. The heat storage structure of a cogeneration central heating system according to claim 1, wherein the calculation formula of V (m/s) is: v= (0.354×g) Calculation of ×υ）/D 2 Wherein G is Calculation of (t/h) is the calculated flow of the first-level pipe network, v (m) 3 The specific volume of the medium water in the pipeline is shown as the ratio of/kg); d (m) is the inner diameter of a water return pipeline of the primary heat supply pipe network.
3. Heat storage structure of cogeneration central heating system according to claim 2, characterized in that said G Calculation of The formula of (t/h) is: g Calculation of = (0.86×a× q)/(T1-T2)/1000, wherein a (m) 2 ) For heating area, q (W/m) 2 ) In order to calculate the heat consumption index, T1 (DEG C) is used for calculating the water supply temperature for the primary heat supply pipe network; t2 (DEG C) is the temperature of the return water calculated by the primary heat supply pipe network.
4. The heat storage structure of a cogeneration central heating system according to claim 1, wherein the calculation formula of V (m/s) is: v= (0.354×g) Actual practice is that of ×υ）/D 2 ，G Actual practice is that of The actual flow of the peak period primary pipe network or the average actual flow of the peak period primary pipe network and the average period primary pipe network.
5. The heat accumulation structure of cogeneration central heating system according to any one of claims 1-4, wherein the pressure sensor and the temperature sensor are respectively arranged on the pipelines of the primary side and the secondary side of the heat exchange primary station and each secondary heat exchange station, and the pressure sensor and the temperature sensor are respectively arranged on the water supply pipeline and the water return pipeline of the primary heating pipeline network at the front side and the rear side of the primary heat accumulation water return valve.
6. The heat storage structure of cogeneration central heating system according to claim 5, wherein the water supply pipeline of the primary heating network comprises a water supply main pipeline and a water supply branch pipeline, and the water return main pipeline comprises a water return main pipeline and a water return branch pipeline; the water supply branch pipeline and the backwater branch pipeline are used for connecting the primary side of the heat exchanger in the secondary heat exchange station with the main water supply pipeline and the main backwater pipeline; the primary heat storage water return valve is arranged between the main water supply pipeline and the main water return pipeline.
7. The heat storage structure of cogeneration central heating system according to claim 6, wherein the water supply pipeline of the primary heating network comprises a water supply main pipeline and a water supply branch pipeline, and the water return main pipeline comprises a water return main pipeline and a water return branch pipeline; the primary water inlet and the primary water outlet of the heat exchanger in the secondary heat exchange station are respectively connected with the main water supply pipeline and the main water return pipeline through the water supply branch pipeline and the main water return pipeline; the primary heat storage water return valve is arranged between a water supply branch pipeline and a water return branch pipeline in the secondary heat exchange station, and primary heat storage water return valves are respectively arranged between the water supply branch pipelines and the water return branch pipelines in the n secondary heat exchange stations within the range of L meters from the heat exchange primary station.
8. A heat storage method of a cogeneration central heating system according to claim 1 or 6, characterized by comprising the steps of:
controlling the opening degree of the first-stage heat storage water return valve to be larger when the temperature rise speed of the water supply temperature of the first-stage heat supply pipe network is larger than S, so that the temperature rise speed of the water supply temperature of the first-stage heat supply pipe network is smaller than or equal to S;
controlling the opening of the primary heat storage water return valve to be smaller when the temperature drop speed of the water supply temperature of the primary heat supply pipe network is more than S, so that the temperature drop speed of the water supply temperature of the primary heat supply pipe network is less than or equal to S;
step three, when the temperature rise speed or the temperature fall speed of the water supply temperature of the primary heat supply pipe network is detected to be less than or equal to S, the primary heat storage water return valve is maintained;
in the first-stage heat storage water return valve adjusting process, when three boundary conditions t3=t4 and delta P are met J =ΔP Minimum of 、G1 Operation =G1 Maximum value When the first-stage heat storage water return valve reaches the allowable maximum opening degree;
wherein: s is the maximum lifting speed allowed by the water supply temperature of a primary heat supply pipe network at the outlet of the secondary side of a heat exchanger in a heat exchange primary station;
ΔP J the pressure difference value of a primary side water supply and return pipeline of a heat exchanger in the secondary heat exchange station is the most unfavorable point;
ΔP minimum of Is a secondary heat exchange stationThe minimum differential pressure value of the primary side water supply and return pipeline of the internal heat exchanger;
G1 operation The method comprises the steps that the flow rate of the primary heat supply pipe network is t/h, and a flowmeter is installed on the secondary side of a heat exchanger in a heat exchange primary station for acquisition;
G1 maximum value The maximum flow conveying capacity of the primary heat supply pipe network is given by the unit of t/h;
t3 is the return water temperature of the primary heat-storage later-stage heat supply pipe network, and is the temperature after the water supply pipeline of the primary heat supply pipe network is partially mixed with the return water pipeline of the primary heat supply pipe network after the primary heat-storage return water valve is opened;
t4 is the return line safety boundary temperature.
9. A heat storage method of a cogeneration central heating system according to claim 7, comprising the steps of:
when the temperature rise speed of the water supply temperature of the primary heat supply pipe network is more than S, the opening of the primary heat storage water return valve is controlled to be larger by the automatic control system, so that the temperature rise speed of the water supply temperature of the primary heat supply pipe network is less than or equal to S; the high-temperature hot water part in the water supply pipeline of the primary heat supply pipe network enters the water return pipeline to store heat to form high-temperature backwater, so that the heat storage of the primary heat supply pipe network is realized;
when the temperature drop speed of the water supply temperature of the primary heat supply pipe network is more than S, the automatic control system controls the opening of the primary heat storage water return valve to be smaller, so that the temperature drop speed of the water supply temperature of the primary heat supply pipe network is less than or equal to S;
step three, when the temperature rise speed or the temperature fall speed of the water supply temperature of the primary heat supply pipe network is detected to be less than or equal to S, the opening of the primary heat storage water return valve is kept unchanged;
wherein: s is the maximum lifting speed allowed by the water supply temperature of a primary heat supply pipe network at the outlet of the secondary side of a heat exchanger in a heat exchange primary station, wherein the unit is ℃/h, and generally 4-6 ℃/h is taken;
in the first-stage heat storage water return valve adjusting process, when the ith first-stage heat storage water return valve meets three boundary conditions t3=t4 and delta P iJ =ΔP Minimum of 、G i 1 Operation =G i 1 Maximum value Any one of the stripsWhen the part is made, the ith first-stage heat storage water return valve reaches the maximum allowable opening;
ΔP iJ the pressure difference value of a primary side water supply and return pipeline of a heat exchanger in the secondary heat exchange station is the most unfavorable point;
ΔP minimum of The minimum differential pressure value of the primary side water supply and return pipeline of the heat exchanger in the secondary heat exchange station is obtained;
G i 1 operation The operation flow of the primary heat supply pipe network is provided;
G i 1 maximum value The maximum flow conveying capacity of the primary heat supply pipe network is provided;
t3 is the return water temperature of the primary heat-storage later-stage heat supply pipe network, and is the temperature after the water supply pipeline of the primary heat supply pipe network is partially mixed with the return water pipeline of the primary heat supply pipe network after the primary heat-storage return water valve is opened;
t4 is the return line safety boundary temperature.
CN202311588414.6A 2023-11-27 2023-11-27 Heat storage structure and method of cogeneration central heating system Pending CN117346202A (en)

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* Cited by examiner, † Cited by third party
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CN117830033A (en) * 2024-03-06 2024-04-05 深圳市前海能源科技发展有限公司 Regional cooling and heating system regulation and control method and device, electronic equipment and storage medium

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* Cited by examiner, † Cited by third party
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CN117830033A (en) * 2024-03-06 2024-04-05 深圳市前海能源科技发展有限公司 Regional cooling and heating system regulation and control method and device, electronic equipment and storage medium
CN117830033B (en) * 2024-03-06 2024-06-04 深圳市前海能源科技发展有限公司 Regional cooling and heating system regulation and control method and device, electronic equipment and storage medium

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