CN110873335A - Heat transfer system and adjustment control method thereof - Google Patents

Heat transfer system and adjustment control method thereof Download PDF

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Publication number
CN110873335A
CN110873335A CN201911247044.3A CN201911247044A CN110873335A CN 110873335 A CN110873335 A CN 110873335A CN 201911247044 A CN201911247044 A CN 201911247044A CN 110873335 A CN110873335 A CN 110873335A
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China
Prior art keywords
heat
working medium
medium
radiator
temperature
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Pending
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CN201911247044.3A
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Chinese (zh)
Inventor
龚超
李小荣
冉燊铭
巩李明
李红兵
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Dongfang Boiler Group Co Ltd
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Dongfang Boiler Group Co Ltd
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Priority to CN201911247044.3A priority Critical patent/CN110873335A/en
Publication of CN110873335A publication Critical patent/CN110873335A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J15/00—Arrangements of devices for treating smoke or fumes
    • F23J15/06—Arrangements of devices for treating smoke or fumes of coolers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
    • F27D17/004—Systems for reclaiming waste heat
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
    • F28D21/0001—Recuperative heat exchangers
    • F28D21/0014—Recuperative heat exchangers the heat being recuperated from waste air or from vapors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F27/00—Control arrangements or safety devices specially adapted for heat-exchange or heat-transfer apparatus
    • 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
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/56—Heat recovery units
    • 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
    • Y02E20/30—Technologies for a more efficient combustion or heat usage
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Heat-Pump Type And Storage Water Heaters (AREA)

Abstract

The invention discloses a heat transfer system and an adjustment control method thereof, wherein the system comprises: the hot flue unit comprises a hot flue and a working medium heat absorber arranged in the hot flue; the cold flue unit comprises a cold flue and a working medium radiator arranged in the cold flue; the heat medium water unit comprises a heat medium water tank and a heat medium water pipeline which is communicated with the working medium heat absorber, the heat medium water tank and the working medium heat radiator in series, and the arrangement height of the heat medium water tank is higher than that of the working medium heat absorber and that of the working medium heat radiator; the heat medium water unit also comprises an adjusting bypass which is connected with the working medium radiator in parallel, and the adjusting bypass is provided with an adjusting valve and a heat adjusting heat exchanger. The method is characterized in that adjustment and control are carried out according to the operation load condition of the system and the relation between the heat absorption capacity of the working medium heat absorber and the heat release capacity of the working medium heat radiator, so that the system is suitable for recovering the waste heat of the flue gas at the temperature of 100-350 ℃. The invention can adapt to very wide range of flue gas temperature and working medium temperature.

Description

Heat transfer system and adjustment control method thereof
Technical Field
The invention relates to the technical field of flue gas waste heat recovery, in particular to a heat transfer system and an adjustment control method thereof.
Background
In recent years, the MGGH (or WGGH) system is widely applied to the projects of flue gas waste heat recovery, energy conservation and environmental protection, and the system absorbs the high-temperature flue gas waste heat by using hot medium water and then releases heat in low-temperature flue gas. Fig. 1 shows a schematic structural flow diagram of a conventional MGGH closed circulation system in the prior art, and as shown in fig. 1, the system conventionally adopts a closed heat medium water system, an opening of a heat medium water tank is designed to be arranged at a high position, the high position of the heat medium water tank is used for maintaining the pressure of a working medium in the MGGH system, the operating pressure of a general working medium is 0.4-0.5 MPa, and the temperature of the working medium is controlled within 150 ℃. At the moment, the MGGH system has no problem in operation, a heat medium water tank in the system is used for water supplement and pressure stabilization and is not used as a flow passage of a working medium, and the heat medium water tank is normal-pressure equipment.
However, for the condition of high flue gas temperature, such as a gas heating system of a gas boiler heating medium water type gas heater, a sintering machine or pellets in a steel plant and other items, the flue gas temperature is generally high, the phenomena of vaporization and the like of working media in a heating surface of the existing MGGH (or WGGH) system are generated, the safe and stable operation of the system is endangered, and the conventional MGGH is not suitable for the environment with high flue gas temperature.
In order to solve the problem that the application range of the original MGGH (or WGGH) system to the flue gas temperature and the working medium temperature is small, a heat transfer system which can adapt to a very wide range of the flue gas temperature and the working medium temperature and an adjusting and controlling method thereof are needed to be provided.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a heat transfer system which can adapt to very wide ranges of flue gas temperature and working medium temperature and an adjustment control method thereof.
One aspect of the invention provides a heat transfer system comprising:
the hot flue unit comprises a hot flue and a working medium heat absorber arranged in the hot flue;
the cold flue unit comprises a cold flue and a working medium radiator arranged in the cold flue;
the heat medium water unit comprises a heat medium water tank and a heat medium water pipeline which is communicated with the working medium heat absorber, the heat medium water tank and the working medium heat radiator in series, and the arrangement height of the heat medium water tank is higher than that of the working medium heat absorber and that of the working medium heat radiator; the heat medium water unit further comprises an adjusting bypass which is connected with the working medium radiator in parallel, and an adjusting valve and a heat adjusting heat exchanger are arranged on the adjusting bypass.
According to one embodiment of the heat transfer system of the invention, the heating medium water tank is a closed pressurized water tank and is provided with a liquid level meter and a safety valve, and the heating medium water tank is also connected with a water replenishing pipeline provided with a shut-off valve.
According to an embodiment of the heat transfer system of the present invention, a booster pump, a temperature monitoring thermocouple and a pressure transmitter are disposed on the heat medium water pipeline between the working medium heat absorber and the working medium heat radiator, a temperature monitoring thermocouple and a pressure transmitter are disposed on the heat medium water pipeline between the working medium heat absorber and the working medium water tank, a temperature monitoring thermocouple is disposed on the heat medium water pipeline between the heat medium water tank and the working medium heat radiator, and a temperature monitoring thermocouple is disposed at an outlet of the heat regulating heat exchanger in the regulating bypass.
According to one embodiment of the heat transfer system of the present invention, the heat regulating heat exchanger is connected to a cold medium source through a cold medium inlet pipe and a cold medium outlet pipe, the cold medium inlet pipe is provided with a regulating valve, and the cold medium outlet pipe is provided with a shutoff valve.
According to an embodiment of the heat transfer system of the present invention, temperature monitoring thermocouples are disposed in front of and behind the working medium heat absorber in the hot flue and in front of and behind the working medium heat radiator in the cold flue, wherein a medium in the hot flue is hot flue gas, a medium in the cold flue is flue gas, air or coal gas, and the working medium heat absorber or the working medium heat radiator is a tubular heat exchanger or a plate heat exchanger.
According to an embodiment of the heat transfer system of the present invention, the working medium outlet of the working medium heat spreader is provided with a shut-off valve and the working medium inlet is provided with a regulating valve, and both the working medium inlet and the working medium outlet of the working medium heat absorber are provided with shut-off valves.
According to the adjustment control method of the heat transfer system, adjustment control is performed according to the operation load condition of the system and the relation between the heat absorption capacity of the working medium heat absorber and the heat release capacity of the working medium heat radiator, so that the system is suitable for flue gas waste heat recovery at 100-350 ℃.
According to one embodiment of the adjustment control method of the heat transfer system, when the system runs under full load and the heat absorption capacity of the working medium heat absorber is equal to the heat release capacity of the working medium heat radiator, the adjustment bypass is closed to enable the system to run under the design working condition.
According to an embodiment of the adjustment control method of the heat transfer system, when the system operates under low load and the heat absorption capacity of the working medium heat absorber is equal to the heat release capacity of the working medium heat radiator, the adjusting bypass is opened, the heat adjusting heat exchanger is controlled not to be put into operation, the temperature of outlet flue gas of the working medium heat radiator is controlled by adjusting the heat medium water flow entering the working medium heat radiator and the adjusting bypass, and meanwhile, the temperature of the heat medium water obtained by mixing the outlet heat medium water of the working medium heat radiator and the outlet heat medium water of the adjusting bypass is controlled to reach the temperature required by the working medium.
According to an embodiment of the adjustment control method of the heat transfer system, when the heat absorption capacity of the working medium heat absorber is larger than the heat release capacity of the working medium heat radiator, the adjustment bypass is opened, the heat regulation heat exchanger is controlled to be put into operation, the outlet flue gas temperature of the working medium heat radiator is controlled by respectively regulating the heat medium water flow entering the working medium heat radiator and the heat regulation heat exchanger, meanwhile, the outlet heat medium water temperature of the heat regulation heat exchanger is regulated by regulating the cold medium flow of the heat regulation heat exchanger, and further the inlet heat medium water temperature of the working medium heat absorber is regulated.
Compared with the prior art, the invention has the following advantages:
1) the device is suitable for a wider flue gas temperature range and is also suitable for a wider working medium temperature range;
2) the line adjustment and control are flexible and convenient;
3) the arrangement is convenient, the situation that a conventional MGGH (or WGGH) system needs a very high position to arrange a heat medium water tank is avoided, and the arrangement of the heat medium water tank is only higher than the positions of a working medium heat absorber and a working medium heat radiator;
4) adjusting the heat transfer distribution of the system according to the load change of the system; the end difference of the two heat exchangers can be adjusted manually according to the increase and decrease of the areas of the working medium heat absorber and the working medium heat radiator, and the design of the system can be carried out by integrating the influence of cost and low-temperature corrosion.
Drawings
Fig. 1 shows a schematic structural flow diagram of a conventional MGGH closed cycle system in the prior art.
Fig. 2 shows a schematic flow diagram of a heat transfer system according to an exemplary embodiment of the present invention.
Fig. 3 is a schematic view showing a flow of the structure of the heat transfer system in embodiment 1.
Fig. 4 is a schematic view showing a flow of the structure of the heat transfer system in embodiment 2.
Description of reference numerals:
1-a hot flue; 2-working medium heat absorber; 3-a booster pump; 4-cooling the flue; 5-working medium radiator; 6-heat regulating heat exchanger; 7-a heating medium water tank; 8-a liquid level meter; 9-safety valve; 10-a regulation bypass; 11-a regulating valve; 12-a shut-off valve; 13-temperature monitoring thermocouple; 14-a pressure transmitter; 15-water supply pipeline; 16-a heating medium water pipeline; 17-cold medium pipe.
Detailed Description
All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.
Any feature disclosed in this specification may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.
The heat transfer system and the adjustment control method thereof according to the present invention will be described in detail with reference to the accompanying drawings.
Fig. 2 shows a schematic flow diagram of a heat transfer system according to an exemplary embodiment of the present invention.
As shown in fig. 2, according to an exemplary embodiment of the present invention, the heat transfer system includes a hot flue unit, a cold flue unit, and a hot water unit, wherein the hot flue unit is a component for exchanging heat with hot flue gas by using a working medium, the cold flue unit is a component for exchanging heat with a heat-absorbed working medium by using cold flue gas, and the hot water unit is a component for providing circulation of the working medium hot water.
In particular, the hot flue unit comprises a hot flue 1 and a working medium heat sink 2 arranged in the hot flue 1. The hot flue gas in the hot flue 1 can be hot flue gas from a boiler or hot flue gas from an industrial furnace such as steel; the working medium heat absorber 2 is arranged in the hot flue 1, and the heat of the flue gas is absorbed by the working medium in the pipe. The working medium heat absorber 2 can be a tubular heat exchanger and also can be a plate heat exchanger.
Likewise, the cold flue unit comprises a cold flue 4 and a working medium radiator 5 arranged in the cold flue 4. The medium in the cold flue 4 can be flue gas, air or coal gas, i.e. not limited to flue systems, but also other medium pipe systems. The working medium radiator 5 is arranged in the cold flue 4, and the working medium in the pipe is used for heating the cold flue gas, air or coal gas in the cold flue. The working medium heat radiator 5 can be a tubular heat exchanger and also can be a plate heat exchanger.
The heat medium water unit comprises a heat medium water tank 7 and a heat medium water pipeline 16 which is communicated with the working medium heat absorber 2, the heat medium water tank 7 and the working medium heat radiator 5 in series. That is, the heat medium water tank 7 is arranged in series in the heat medium water pipeline 16 and is arranged in series in the system as a channel of a medium, and can be arranged horizontally or vertically, and the arrangement height of the heat medium water tank 7 is only higher than the arrangement height of the working medium heat absorber 2 and the arrangement height of the working medium heat radiator 5, so as to ensure that the pressure of the working medium in the heat medium water tank 7 is lower than that of the working medium heat absorber 2 and the working medium heat radiator 5, thereby ensuring that the working medium in the working medium heat absorber 2 and the working medium heat radiator 5 is not vaporized.
Preferably, the heat medium water tank 7 is a closed pressurized water tank and is provided with a liquid level meter 8 for measuring the liquid level of the heat medium water tank 7 and a safety valve 9 for performing safety protection on the system, the heat medium water tank 7 is further connected with a water replenishing pipeline 15 provided with a shut-off valve 12, the water replenishing pipeline 15 is used for replenishing water at the initial stage of operation of the system, and the shut-off valve on the water replenishing pipeline can control to close the water replenishing pipeline. Different from a heating medium water tank in a conventional normal-pressure MGGH system scheme, the working pressure of the heating medium water tank in the system is far higher than the atmospheric pressure, the pressure must be ensured to be stable and not to fluctuate sharply during the operation of the system, the heating medium water tank plays a role in stabilizing the pressure by the phase change of steam and water inside the heating medium water tank, and the operating pressure of the system is balanced by the steam-water ratio of a saturated steam-water mixture in the heating medium water tank.
According to the invention, the hot medium water unit also comprises an adjusting bypass 10 which is connected with the working medium radiator 5 in parallel, and the adjusting bypass 10 is provided with an adjusting valve 11 for adjusting the flow of the pipeline and a heat adjusting heat exchanger 6 for sending the redundant energy of the system to other places.
The regulating bypass 10 has two functions: firstly, when this system need be to system external heat release, realize releasing heat to outside through heat regulation heat exchanger, secondly when this system need not be to system external heat release, close the cold medium pipeline on the heat regulation heat exchanger and make the heat regulation heat exchanger only as the medium passageway, adjust the working medium flow of bypass and working medium heat release ware through the adjustment, adjust the entry working medium temperature of working medium heat absorber.
The heat regulating heat exchanger 6 is connected with a cold medium source through a cold medium pipeline 17, the cold medium pipeline 17 comprises a cold medium inlet pipeline and a cold medium outlet pipeline, a regulating valve is arranged on the cold medium inlet pipeline, and a shutoff valve is arranged on the cold medium outlet pipeline. The heat adjusting heat exchanger 6 is arranged on the adjusting bypass 10 and is arranged in parallel with the working medium radiator 5, the heat adjusting heat exchanger 6 is system matching equipment and can be used for sending redundant heat of a system to other places, and a valve on a cold medium pipeline of the heat adjusting heat exchanger can be closed to enable the heat adjusting heat exchanger to be only used as a medium channel to adjust the temperature of working medium at the inlet of the working medium radiator.
Preferably, a booster pump 3, a temperature monitoring thermocouple 13 and a pressure transmitter 15 are arranged on the heat medium water pipeline between the working medium heat absorber 1 and the working medium heat emitter 5, a temperature monitoring thermocouple 13 and a pressure transmitter 15 are arranged on the heat medium water pipeline between the working medium heat absorber 2 and the heat medium water tank 7, a temperature monitoring thermocouple 13 is arranged on the heat medium water pipeline between the heat medium water tank 7 and the working medium heat emitter 5, and a temperature monitoring thermocouple 13 is arranged at the outlet of the heat regulation heat exchanger 6 in the regulation bypass 10.
In addition, temperature monitoring thermocouples 13 are provided in the front and rear of the heat absorber 2 for the medium in the hot flue 1 and in the front and rear of the heat radiator 5 for the medium in the cold flue 4. The working medium outlet of the working medium heat radiator 5 is provided with a shutoff valve 12, the working medium inlet is provided with a regulating valve 11, and the working medium inlet and the working medium outlet of the working medium heat absorber 2 are both provided with the shutoff valve 12.
The regulating valve is used for regulating the flow of the corresponding pipeline, the shutoff valve is used for shutting off the corresponding pipeline, the temperature detection thermocouple is used for measuring the temperature and transmitting a temperature signal to the control end for system control, and the pressure transmitter is used for measuring the pressure of the corresponding pipeline and transmitting a pressure signal to the control end for system control.
From this, heat medium water pipeline 16 connects whole system into a closed heat medium water circulating system, and this closed heat medium water system internal working medium is according to: booster pump → working medium heat absorber → heat medium water tank → working medium heat radiator & regulation bypass (heat regulation heat exchanger) → booster pump flow, the working medium is heat medium water in the pipeline.
The invention also provides an adjustment control method of the heat transfer system, which needs to adjust and control according to the operation load condition of the system and the relationship between the heat absorption capacity of the working medium heat absorber and the heat release capacity of the working medium heat radiator, so that the system is suitable for flue gas waste heat recovery at 100-350 ℃.
The system has three common working modes, which are described in detail below.
The first method comprises the following steps: when the system runs under full load and the heat absorption capacity of the working medium heat absorber is equal to the heat release capacity of the working medium heat radiator, the adjusting bypass is closed to enable the system to run under the design working condition.
When the system runs at full load and the heat absorption capacity of the working medium heat absorber is equal to the heat release capacity of the working medium heat radiator, the system does not need to release heat outwards at the moment, the system is just at the designed working condition point after the bypass is adjusted to be closed, and the system can run normally in sequence.
And the second method comprises the following steps: when the system operates under low load and the heat absorption capacity of the working medium heat absorber is equal to the heat release capacity of the working medium heat radiator, the adjusting bypass is opened, the heat adjusting heat exchanger is controlled not to be put into operation, the outlet flue gas temperature of the working medium heat radiator is controlled by adjusting the flow of the heat medium water entering the working medium heat radiator and the adjusting bypass, and meanwhile, the temperature of the heat medium water mixed by the outlet heat medium water of the working medium heat radiator and the outlet heat medium water of the adjusting bypass is controlled to reach the temperature required by the working medium.
The system operates at low load, when the heat absorption capacity of the working medium heat absorber is equal to the heat release capacity of the working medium heat radiator, the system does not need to release heat outwards, but the heat exchange capacity of the two heat exchangers is difficult to balance due to the fact that the heat exchange areas of the working medium heat absorber and the working medium heat radiator are not matched, a bypass needs to be adjusted, and the bypass pipeline is adjusted to be put into operation.
But because the system does not release heat outwards, the heat regulating heat exchanger on the regulating bypass is not put into operation, the regulating bypass only plays a role of a medium channel, the temperature of the flue gas at the outlet of the working medium heat radiator is controlled by regulating the flow entering the working medium heat radiator and regulating the bypass, and simultaneously the temperature of the mixed heat medium water at the outlet of the working medium heat radiator and the heat medium water of the regulating bypass reaches the temperature required by the working medium heat absorber.
The control method specifically comprises the following steps: firstly, regulating the total working medium flow of the system through a booster pump, and simultaneously regulating the inlet working medium temperature of a working medium heat absorber, thereby controlling the outlet flue gas temperature of the working medium heat absorber; the outlet flue gas temperature of the working medium heat radiator is adjusted by adjusting the flow of the heating medium water entering the working medium heat radiator, and a temperature monitoring thermocouple at the flue gas outlet of the working medium heat radiator is associated with an adjusting valve at a working medium inlet of the working medium heat radiator. And the rest of the heat medium water is mixed with the heat medium water at the outlet of the working medium heat radiator after passing through the regulating bypass (not participating in heat exchange), and then enters the working medium heat absorber through the booster pump.
And the third is that: when the heat absorption capacity of the working medium heat absorber is larger than the heat release capacity of the working medium heat radiator, the adjusting bypass is opened, the heat adjusting heat exchanger is controlled to be put into operation, the outlet flue gas temperature of the working medium heat radiator is controlled by adjusting the flow of the heat medium water entering the working medium heat radiator and the heat adjusting heat exchanger respectively, and meanwhile, the outlet heat medium water temperature of the heat adjusting heat exchanger is adjusted by adjusting the flow of the cold medium of the heat adjusting heat exchanger, so that the inlet heat medium water temperature of the working medium heat absorber is.
The control method specifically comprises the following steps: firstly, regulating the total working medium flow of the system through a booster pump, and simultaneously regulating the inlet working medium temperature of a working medium heat absorber, thereby controlling the outlet flue gas temperature of the working medium heat absorber; the flue gas temperature at the outlet of the working medium heat radiator is adjusted by adjusting the flow of the heat medium water entering the working medium heat radiator, and a temperature monitoring thermocouple at the working medium outlet of the working medium heat radiator is associated with an adjusting valve at the working medium inlet of the working medium heat radiator. The heat exchange quantity of the heat regulating heat exchanger is controlled by regulating the cooling water quantity entering the heat regulating heat exchanger, so that the outlet heat medium water temperature of the heat regulating heat exchanger is controlled, and finally the temperature of the mixed outlet heat medium water of the heat regulating heat exchanger and the outlet heat medium water of the working medium heat radiator is controlled to meet the requirement of the working medium temperature of the inlet of the working medium heat absorber. The temperature monitoring thermocouple at the working medium inlet of the working medium heat absorber is associated with the regulating valve on the cold medium pipeline of the heat regulating heat exchanger.
The system is suitable for indirect heating of coal gas by high-temperature flue gas in a coal gas boiler, avoids leakage of the flue gas to the coal gas in the direct heating process of the coal gas, is also suitable for indirect heating of low-temperature flue gas by high-temperature flue gas in a flue gas purification system at the tail part of a steel sintering machine, and realizes reheating or whitening of the flue gas. The system is suitable for replacing part of the tubular air pre-heaters, saves the space occupied by the tubular air pre-heaters, arranges the denitration device, and is particularly suitable for increasing the denitration device in a modification project and under the condition of short space. In addition, through the setting of this system closed area pressure heat medium water tank, not only be applicable to the lower condition of low parameter such as heat medium water temperature, also can be used to under the high parameter such as heat medium water temperature, when pressure is higher, prevent the vaporization of heat medium water. The area of the working medium heat radiator is reduced by improving the heat exchanger end difference of the working medium heat radiator, and the cost can be greatly reduced particularly when the working medium heat radiator adopts high-grade steel (such as 2205 stainless steel or 316L stainless steel). The wall temperature of the heat exchanger of the working medium heat absorber can be improved by improving the temperature of the working medium at the inlet and the outlet of the working medium heat absorber, so that the risk of low-temperature corrosion of the working medium heat absorber can be effectively reduced.
The present invention will be further described with reference to the following specific examples.
Example 1: the high-temperature flue gas from the boiler indirectly heats the blast furnace gas for preheating the gas
Design conditions are as follows: the temperature of high-temperature flue gas discharged from the boiler is 280 ℃, the temperature is reduced to 230 ℃ after heat release, the released heat is used for heating blast furnace gas at 80 ℃ to 170 ℃, and the flue gas volume is 69 ten thousand Nm3Per h, 43 ten thousand Nm of gas3/h。
Fig. 3 is a schematic view showing a flow of the structure of the heat transfer system in embodiment 1. As shown in fig. 3, the working medium heat absorber is arranged behind the high-temperature air preheater and in front of the low-temperature air preheater, and the working medium heat radiator is arranged on the gas pipeline and used for heating the gas by recovering the heat of the high-temperature flue gas.
Through the implementation of the scheme of the system, high-temperature hot flue gas from the boiler indirectly heats the blast furnace gas, the risk of gas leakage caused by the fact that the blast furnace gas is directly heated by the flue gas is avoided, the steam-water phase change in the heating medium water tank plays a role in stabilizing the pressure of the system, the working pressure of the system is 2.5MPa, and when the boiler operates under variable working conditions, the system can be adjusted at any time along with the change of the working conditions of the boiler when the temperature and the amount of the flue gas change. Meanwhile, the waste heat of the flue gas can be recovered to other systems by adding a heat regulating heat exchanger, such as low condensed water or heat supply network water.
Example 2: the high-temperature flue gas from the steel sintering machine is used for indirectly heating the desulfurized clean flue gas for the whitening of the flue gas
Design conditions are as follows: the temperature of high-temperature flue gas discharged from the steel sintering machine is between 310 ℃, the temperature is reduced to 174 ℃ after heat release, the released heat is used for heating the purified flue gas subjected to desulfurization at 50 ℃ to 80 ℃ for flue gas whitening, and the high-temperature flue gas amount is 20 ten thousand Nm3Per, 113 ten thousand Nm of purified flue gas after desulfurization3/h。
Fig. 4 is a schematic view showing a structural flow of the heat transfer system in embodiment 2, and as shown in fig. 4, the working medium heat absorber is arranged in the high-temperature flue at the outlet of the sintering machine, and the working medium heat radiator is arranged on the flue at the outlet of the desulfurization tower, and is used for heating the desulfurized clean flue gas to eliminate white by recovering the heat of the high-temperature flue gas.
Through the implementation of the system, the high-temperature hot flue gas discharged from the sintering machine indirectly heats the desulfurized clean flue gas, the difficulty in arrangement caused by the fact that the high-temperature flue gas directly heats the desulfurized clean flue gas is avoided, in addition, the steam-water phase change in the heating medium water tank plays a role in stabilizing the pressure of the system, the working pressure of the system is 0.8MPa, and when the temperature and the quantity of the flue gas change, the system can be adjusted at any time along with the change of the working condition of the sintering machine.
The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed.

Claims (10)

1. A heat transfer system, comprising:
the hot flue unit comprises a hot flue and a working medium heat absorber arranged in the hot flue;
the cold flue unit comprises a cold flue and a working medium radiator arranged in the cold flue;
the heat medium water unit comprises a heat medium water tank and a heat medium water pipeline which is communicated with the working medium heat absorber, the heat medium water tank and the working medium heat radiator in series, and the arrangement height of the heat medium water tank is higher than that of the working medium heat absorber and that of the working medium heat radiator; the heat medium water unit further comprises an adjusting bypass which is connected with the working medium radiator in parallel, and an adjusting valve and a heat adjusting heat exchanger are arranged on the adjusting bypass.
2. The heat transfer system of claim 1, wherein the heat medium tank is a closed pressurized water tank and is provided with a level gauge and a safety valve, and the heat medium tank is further connected to a water replenishing pipe provided with a shut-off valve.
3. The heat transfer system according to claim 1, wherein a booster pump, a temperature monitoring thermocouple, and a pressure transmitter are provided in the heat medium water pipe between the working medium heat absorber and the working medium heat radiator, a temperature monitoring thermocouple and a pressure transmitter are provided in the heat medium water pipe between the working medium heat absorber and the working medium water tank, a temperature monitoring thermocouple is provided in the heat medium water pipe between the heat medium water tank and the working medium heat radiator, and a temperature monitoring thermocouple is provided in an outlet of the heat regulating heat exchanger in the regulating bypass.
4. The heat transfer system of claim 1, wherein the heat conditioning heat exchanger is connected to a source of cold medium by a cold medium inlet conduit having a conditioning valve disposed thereon and a cold medium outlet conduit having a shutoff valve disposed thereon.
5. The heat transfer system according to claim 1, wherein temperature monitoring thermocouples are disposed in front of and behind the working medium heat absorber in the hot flue and in front of and behind the working medium heat radiator in the cold flue, wherein the medium in the hot flue is hot flue gas, the medium in the cold flue is flue gas, air or coal gas, and the working medium heat absorber or the working medium heat radiator is a tubular heat exchanger or a plate heat exchanger.
6. The heat transfer system of claim 1, wherein the working medium outlet of the working medium heat spreader is provided with a shut-off valve and the working medium inlet is provided with a regulating valve, and the working medium inlet and the working medium outlet of the working medium heat absorber are both provided with shut-off valves.
7. The adjustment control method of the heat transfer system according to any one of claims 1 to 6, characterized in that adjustment control is performed according to the operation load condition of the system and the relationship between the heat absorption capacity of the working medium heat absorber and the heat release capacity of the working medium heat radiator, so that the system is suitable for the waste heat recovery of flue gas at 100-350 ℃.
8. The method of claim 7, wherein when the system is operating at full load and the heat absorption capacity of the working medium heat absorber is equal to the heat release capacity of the working medium heat emitter, the bypass is closed to operate the system under the design condition.
9. The adjustment control method of the heat transfer system according to claim 7, characterized in that when the system is operated under low load and the heat absorption capacity of the working medium heat absorber is equal to the heat release capacity of the working medium heat radiator, the adjustment bypass is opened and the heat adjustment heat exchanger is controlled not to be operated, the temperature of the outlet flue gas of the working medium heat radiator is controlled by adjusting the temperature of the heat medium water entering the working medium heat radiator and the adjustment bypass, and the temperature of the heat medium water after mixing the outlet heat medium water of the working medium heat radiator and the outlet heat medium water of the adjustment bypass is controlled to reach the temperature required by the working medium heat.
10. The adjustment control method of the heat transfer system according to claim 7, wherein when the heat absorption capacity of the working medium heat absorber is greater than the heat release capacity of the working medium heat radiator, the adjustment bypass is opened and the heat regulating heat exchanger is controlled to be put into operation, the outlet flue gas temperature of the working medium heat radiator is controlled by respectively adjusting the flow rates of the heat medium water entering the working medium heat radiator and the heat regulating heat exchanger, and the outlet heat medium water temperature of the heat regulating heat exchanger is adjusted by adjusting the flow rate of the cold medium of the heat regulating heat exchanger, so that the inlet heat medium water temperature of the working medium heat absorber is adjusted.
CN201911247044.3A 2019-12-09 2019-12-09 Heat transfer system and adjustment control method thereof Pending CN110873335A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201911247044.3A CN110873335A (en) 2019-12-09 2019-12-09 Heat transfer system and adjustment control method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201911247044.3A CN110873335A (en) 2019-12-09 2019-12-09 Heat transfer system and adjustment control method thereof

Publications (1)

Publication Number Publication Date
CN110873335A true CN110873335A (en) 2020-03-10

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN201911247044.3A Pending CN110873335A (en) 2019-12-09 2019-12-09 Heat transfer system and adjustment control method thereof

Country Status (1)

Country Link
CN (1) CN110873335A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114111420A (en) * 2021-11-26 2022-03-01 聊城氟尔新材料科技有限公司 Automatic control system and method for tetrafluoroethylene production heat recovery

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114111420A (en) * 2021-11-26 2022-03-01 聊城氟尔新材料科技有限公司 Automatic control system and method for tetrafluoroethylene production heat recovery
CN114111420B (en) * 2021-11-26 2023-12-26 聊城氟尔新材料科技有限公司 Automatic control system and method for heat recovery in tetrafluoroethylene production

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