Centralized heating condensation water recovery optimal control system and method

Abstract

The invention relates to the technical field of condensed water recovery equipment, and discloses a centralized heating condensed water recovery optimization control system and method, and the system comprises a condensed water source which is used for providing a condensed water source; the flash tank is used for generating low-pressure flash steam; the deaerator is used for removing dissolved oxygen in the thermodynamic system; the ORC power generation module is connected with a condensed water source to generate power; the substandard condensate water tank is used for storing substandard condensate water; the up-to-standard condensate water tank is used for storing up-to-standard condensate water; and the desalted water station water tank is used for storing desalted water with different requirements. The condensation water is recycled in a classified mode, the waste heat utilization priority is innovatively provided, the demineralized water heating requirement, the deoxygenated steam requirement and the ORC power generation requirement are met preferentially, and maximum utilization of resources is achieved. And meanwhile, by combining a real-time water quality monitoring and control method, the utilization range of unqualified condensed water is expanded, the operation cost is reduced, the economic benefit is improved by 20% or above, and remarkable environmental protection property and popularization value are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of condensate recovery equipment, and in particular to a centralized heating condensate recovery optimization control system and method. Background Art

[0002] In the heating boiler project of the industrial park, the thermal system supplies steam to various plant areas in the park through the heating boiler, and the steam is recycled to the thermal system in the form of condensate after use. However, condensate is easily affected by oil pollution, metal corrosion products, oxygen corrosion and acid corrosion during the recycling process, so that its water quality cannot meet the quality requirements of boiler feed water. Condensate that is directly recycled without treatment will cause damage to thermal system equipment and pipelines, performance degradation and increased maintenance costs, while direct discharge will cause a large amount of water resources and heat waste. Therefore, condensate with recycling value needs to be finely treated before reuse to reduce water resource waste, heat energy loss, and avoid damage to the thermal system.

[0003] In the prior art, the condensate polishing system is mainly divided into a high-temperature polishing system and a low-temperature polishing system. The high-temperature polishing system cools the high-temperature condensate to below 80°C and uses a high-temperature resistant filter and an ion exchanger for treatment. Although it can reduce heat loss, the system equipment cost is high, the operating cost is high, and the filter element life is short. The low-temperature polishing system cools the condensate to below 40°C and then uses an ordinary filter and an ion exchanger for treatment. Although the equipment and operating costs are relatively low, the heat loss is large. In the traditional cooling polishing system, the high-temperature condensate is heat exchanged with desalted water through a heat exchanger, and then enters the polishing system after the temperature is reduced. The treated condensate is returned to the water supply tank for use in the thermal system. However, this method fails to differentiate the treatment of condensate from different sources, and the waste heat of the condensate is insufficiently utilized, resulting in energy waste.

[0004] In addition, some system designs use absorption heat pumps for cooling, heating and resource utilization, but this technology is not applicable to areas with low demand for cooling, heating and hot water, such as Yunnan, which leads to increased system investment and operating costs and ineffective utilization. Therefore, it is necessary to design an optimization control system that adopts targeted treatment methods based on the water quality characteristics and thermal energy characteristics of condensate from different sources, improves resource recovery efficiency, reduces operating costs, and adapts to the actual needs of different regions. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a centralized heating condensate recovery optimization control system and method to solve the problems that the existing condensate recovery system fails to perform targeted treatment according to the water quality characteristics and thermal energy properties of different sources, resulting in unreasonable water quality treatment, insufficient waste heat utilization and poor regional adaptability.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: a centralized heating condensate recovery optimization control system, comprising:

[0007] Condensate source, used to provide condensate source;

[0008] Flash tanks, used to generate low-pressure steam;

[0009] Deaerator, used to remove dissolved oxygen from thermal systems;

[0010] The ORC power generation module is connected to the condensate source to generate electricity;

[0011] Substandard condensed water tank, used to store substandard condensed water;

[0012] The qualified condensed water tank is used to store the qualified condensed water;

[0013] Desalted water station water tank is used to store desalted water with different requirements.

[0014] Preferably, the condensate water source includes condensate water source one, condensate water source two and condensate water source three, which are respectively used to provide condensate water of different pressures. The outlet end of the condensate water source one is connected to pipeline one, which is connected to a flash tank and a deaerator through pipeline one. The flash tank is connected to the ORC power generation module, the condensate water source two is connected to the ORC power generation module, and the condensate water source three is connected to a substandard condensate water tank and a standard condensate water tank through pipeline four. A temperature sensor, a pressure sensor and a flow meter are installed on the side of the ORC power generation module close to the condensate water source two, the side of the flash tank close to the condensate water source one, and the side of the pipeline four close to the condensate water source three.

[0015] Preferably, the outlet end of the ORC power generation module is connected to pipeline 2 and pipeline 3, and pipeline 2 and pipeline 3 are respectively connected to a substandard condensate water tank and a standard condensate water tank, and electric regulating valves are installed at the tees of pipeline 2 and pipeline 3.

[0016] Preferably, a set of iron and oil removal filters, an online water quality detection module and a flow meter are installed in the middle of pipeline 2, pipeline 3 and pipeline 4, which are used for filtering condensed water, detecting water quality and detecting flow rate respectively.

[0017] Preferably, a pipeline six is ​​connected between the qualified condensate water tank and the deaerator, and a group of water quality online detection modules, a flow meter, and a qualified condensate water pump are installed in the middle of the pipeline six, which are respectively used to detect the flow rate and water quality of the condensate water in the pipeline and to pump the condensate water.

[0018] Preferably, the desalted water station water tank includes a desalted water station raw water tank, a desalted water station ultrafiltration water tank and a desalted water station first-level RO water tank. The outlet on one side of the substandard condensate water tank is connected to the desalted water station water tank through pipeline seven, and a group of temperature sensors, water quality online detection modules, substandard condensate pumps and electric regulating valves are installed in the middle of pipeline seven, which are respectively used for the temperature, water quality, pumping and flow direction control of the condensed water in the pipeline.

[0019] Preferably, the system also includes a bypass heat exchanger, which is connected to the ORC power generation module. The condensate output from the condensate source 2 enters the bypass heat exchanger and is connected to the pipeline 3. The inlet end of the condensate tank that meets the standards is also connected to the pipeline 5. The other end of the pipeline 5 is connected to external desalted water. Two loops are connected in the middle of the pipeline 5, one of which passes through the middle of the bypass heat exchanger, and the other passes through the middle of the substandard condensate tank. Multiple groups of electric regulating valves are installed in the pipeline 5 and the middle of its loops. A group of water quality online detection modules and flow meters are installed near the desalted water replenishment end of the pipeline 5, which are used to detect the water quality and flow rate of the desalted water replenishment, respectively.

[0020] A centralized heating condensate recovery optimization control method comprises the following steps:

[0021] S1. Condensate pressure judgment: high-pressure condensate enters the flash tank from condensate source 1 for flash evaporation. The liquid after flash evaporation enters the ORC power generation module. The steam in the flash evaporation enters the deaerator and steam user through pipeline 1. Medium-pressure condensate enters the ORC power generation module from condensate source 2.

[0022] S2. Condensate water quality detection: the condensate discharged from the ORC power generation module and the condensate entering the condensate source 3 are tested and judged by the water quality online detection module. The qualified condensate enters the qualified condensate water tank, and the unqualified condensate enters the unqualified condensate water tank;

[0023] S3. The supplemented desalted water source enters the condensed water tank that has reached the standard after being tested by the water quality online detection module;

[0024] S4. The condensed water inside the condensed water tank that meets the standards will be tested again and enter the deaerator after meeting the temperature requirements. The condensed water inside the condensed water tank that does not meet the standards will be discharged to the desalted water station tank.

[0025] Preferably, the high, medium and low pressure condensate water pressures are judged to be 0.6 MPa and 0.1 MPa, with pressures greater than or equal to 0.6 MPa being high pressure water and pressures less than 0.1 MPa being low pressure water.

[0026] Preferably, the steam pressure output from the steam outlet of the flash tank is 0.3 MPa.

[0027] Working principle: When the pressure P≥0.6MPa, the condensate first enters the flash tank for flash evaporation (flash pressure = 0.3MPa), generating low-pressure steam for users or deoxygenation in the deaerator for the first waste heat utilization. The condensate after flash evaporation (0.3MPa, 143℃) can be used for ORC power generation, lithium bromide refrigeration or equipment drying according to the site conditions. After heat exchange, the temperature is reduced to below 110℃ for the second waste heat utilization. The cooled condensate passes through the iron removal and oil removal filter (selected to be temperature resistant at 120℃), and then the water quality is tested. If the water quality meets the standard, it is sent to the qualified condensate tank. The water inlet of the condensate tank includes condensate and desalted water. The temperature of the desalted water tank is controlled at 80℃~90℃ (the temperature of the desalted water tank changes synchronously with the required working temperature of the deaerator. When the required working temperature of the deaerator increases, the temperature of the desalted water tank increases. When the required working temperature of the deaerator decreases, the temperature of the desalted water tank decreases together). The desalted water is then pumped into the deaerator for the third waste heat utilization. If the water quality does not meet the standard, it is sent to the unqualified condensate tank, and then sent to the desalted water station raw water tank, desalted water station ultrafiltration water tank, and desalted water station first-level RO water tank according to the water quality.

[0028] When the pressure is 0.6MPa≥P≥0.1MPa, the condensate is first used in ORC power generation, lithium bromide refrigeration or equipment drying. After heat exchange, the temperature is reduced to below 110℃ for the first waste heat utilization. The cooled condensate passes through an iron and oil removal filter (selected to be resistant to 120℃) and then undergoes water quality testing. If the water quality meets the standard, it is sent to a qualified condensate tank. The water inlet of the condensate tank includes condensate and desalted water. The temperature of the desalted water tank is controlled at 80℃~90℃. It is then sent to the deaerator through a desalted water pump for the second waste heat utilization. If the water quality does not meet the standard, it is sent to an unqualified condensate tank, and then sent to the raw water tank of the desalted water station, the ultrafiltration water tank of the desalted water station, and the first-level RO water tank of the desalted water station according to the water quality.

[0029] When the pressure P is less than 0.1MPa, the condensate passes through the iron and oil removal filter (temperature resistance of 120℃), and then the water quality is tested. If the water quality meets the standard, it is sent to the qualified condensate tank. The water inlet of the condensate tank includes condensate and desalted water. The temperature of the desalted water tank is controlled at 80℃~90℃. Then it is sent to the deaerator through the desalted water pump for the first waste heat utilization. If the water quality does not meet the standard, it is sent to the unqualified condensate tank, and then sent to the raw water tank of the desalted water station, the ultrafiltration water tank of the desalted water station, and the first-level RO water tank of the desalted water station according to the water quality.

[0030] The present invention provides a centralized heating condensate water recovery optimization control system and method, which has the following beneficial effects:

[0031] 1. The present invention significantly improves economic benefits by optimizing the waste heat utilization and resource management of condensed water. It innovatively proposes to grade condensed water of different pressures and temperatures through flash evaporation, ORC power generation, lithium bromide refrigeration and other technologies, which improves economic benefits by more than 20% compared with existing technical solutions, and realizes efficient recovery and reuse of energy.

[0032] 2. The present invention accurately classifies condensate resources according to the pressure, temperature and water quality parameters (such as conductivity, silica, oil content, iron content, etc.) of the condensate, and adopts differentiated treatment methods based on this, solving the problem of undifferentiated treatment of condensate from different sources in the prior art. In addition, by proposing a graded treatment scheme for qualified condensate, unqualified condensate and demineralized water replenishment, the scope of condensate recovery is further expanded, and resource utilization is maximized.

[0033] 3. The present invention defines the priority principle for waste heat utilization to ensure efficient allocation of resources. The heating demand of desalted water is met first, and the water temperature is controlled between 80℃ and 90℃; on this basis, flash steam is used to meet the operation demand of the deaerator; if the waste heat resources are still abundant, they are further used for other high-efficiency purposes such as ORC power generation. This priority arrangement not only optimizes the utilization of thermal energy, but also significantly improves the overall economic benefits.

[0034] 4. The present invention optimizes the temperature control of the deaerator to ensure that it always operates in the optimal range of 80°C to 90°C, thereby reducing operating costs and improving deoxidation effects. At the same time, combined with the matching control of flash steam and deoxidized steam, the utilization efficiency of steam resources is maximized, further achieving energy saving and efficiency improvement.

[0035] 5. The present invention ensures the stability and eligibility of water quality by real-time online monitoring of key parameters such as conductivity, silica, total iron, total oil and hardness, combined with scientific data processing methods. In addition, by proposing a water quality calculation method after mixing unqualified condensate with demineralized water, it provides a theoretical basis and practical path for expanding the utilization of unqualified condensate, greatly improving resource utilization.

[0036] 6. The present invention sets a hot water coil in the unqualified condensate tank, which not only increases the temperature of the desalted water, but also reduces the temperature of the unqualified condensate to meet the subsequent treatment requirements by exchanging heat with the desalted water. This design fully recovers the waste heat and reduces the energy consumption and operating cost of the water treatment system.

[0037] 7. The present invention not only greatly reduces the operating cost, but also significantly improves the economic benefits, resource utilization and environmental protection of industrial applications through accurate classification, waste heat utilization priority arrangement, intelligent monitoring and control. These innovations and improvements make the present invention have important technical value and promotion significance in the field of condensate recovery and resource utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a system diagram of the present invention;

[0039] Figure 2 It is a schematic diagram of the qualified water quality process in the present invention;

[0040] Figure 3 It is a schematic diagram of the unqualified water quality process in the present invention;

[0041] Figure 4 It is a schematic diagram of the deaerator feed water temperature control process in the present invention;

[0042] Figure 5 It is a schematic diagram of the low-pressure steam production control process of the present invention;

[0043] Figure 6 It is a schematic diagram of the preliminary screening process of condensate water in the present invention;

[0044] Figure 7 It is a reference diagram of the water quality of the steam boiler feed water in the present invention;

[0045] Figure 8 It is the boiler feed water quality reference diagram in the present invention;

[0046] Fig. 9 This is a diagram of the hot water ORC power generation process system in the present invention.

[0047] Among them, 1. Condensate source; 101. Condensate source one; 102. Condensate source two; 103. Condensate source three; 2. Flash tank; 3. Deaerator; 4. ORC power generation module; 5. Iron and oil removal filter; 6. Water quality online detection module; 7. Flow meter; 8. Electric regulating valve; 9. Substandard condensate tank; 10. Standard condensate tank; 11. Bypass heat exchanger; 12. Pipeline one; 13. Pipeline two; 14. Pipeline three; 15. Pipeline four; 16. Pipeline five; 17. Temperature sensor; 18. Pressure sensor; 19. Pipeline six; 20. Standard condensate pump; 21. Pipeline seven; 22. Substandard condensate pump; 23. Desalted water station water tank; 2301. Desalted water station raw water tank; 2302. Desalted water station ultrafiltration water tank; 2303. Desalted water station first-level RO water tank. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] Please see attached Figure 1 , the embodiment of the present invention provides a centralized heating condensate recovery optimization control system, including a condensate source 1, for providing a condensate source;

[0050] Flash tank 2, for generating low-pressure steam;

[0051] Deaerator 3, used to remove dissolved oxygen in the thermal system;

[0052] The ORC power generation module 4 is connected to the condensate source 1 to generate electricity;

[0053] Substandard condensed water tank 9, used for storing substandard condensed water;

[0054] The qualified condensed water tank 10 is used to store the qualified condensed water;

[0055] The desalted water station water tank 23 is used to store desalted water with different requirements.

[0056] The condensate source 1 includes a condensate source 101, a condensate source 2 102 and a condensate source 3 103, which are respectively used to provide condensate of different pressures. The outlet end of the condensate source 101 is connected to a pipeline 12, and the flash tank 2 and the deaerator 3 are connected through the pipeline 12. The flash tank 2 is connected to the ORC power generation module 4, and the condensate source 2 102 is connected to the ORC power generation module 4. The condensate source 3 103 is connected to a substandard condensate tank 9 and a standard condensate tank 10 through a pipeline 4 15. A temperature sensor 17, a pressure sensor 18 and a flow meter 7 are installed on one side of the ORC power generation module 4 close to the condensate source 2 102, the side of the flash tank 2 close to the condensate source 101, and the side of the pipeline 4 15 close to the condensate source 3 103.

[0057] Please see attached Figure 2The outlet of the ORC power generation module 4 is connected to pipeline 2 13 and pipeline 3 14, which are respectively connected to the substandard condensate tank 9 and the qualified condensate tank 10, and electric regulating valves 8 are installed at the three-way joints of pipeline 2 13 and pipeline 3 14. A group of iron removal and oil removal filters 5, water quality online detection module 6 and flow meter 7 are installed in the middle of pipeline 2 13, pipeline 3 14 and pipeline 4 15, which are respectively used for filtering, water quality detection and flow detection of condensate. According to the pressure of condensate, it is classified into at least three categories: high, medium and low. Condensate under different pressures is not mixed, and different condensate waste heat utilization facilities are used separately. The high, medium and low pressure condensate pressures are judged to be 0.6MPa and 0.1MPa. 0.6MPa or more is high pressure water, and less than 0.1MPa is low pressure water.

[0058] The condensate water source 101 outputs condensate water pressure greater than or equal to 0.6MPa. The condensate water under this water pressure first enters the flash tank 2 for flash evaporation. The flash evaporation pressure = 0.3MPa, and low-pressure steam is generated for user use or deoxygenated by the deaerator 3 for the first waste heat utilization. The condensate water after flash evaporation is 0.3MPa and 143℃, depending on the site conditions. It can be transported to the ORC power generation module 4 for power generation, lithium bromide refrigeration or equipment drying, etc. After heat exchange, the temperature is reduced to below 110℃ for the second waste heat utilization. After the cooling, the condensate water passes through the iron and oil removal filter 5, and then passes through the water quality online detection module 6 for water quality detection. If the water quality meets the standard, it is sent to the condensate water tank 10 that meets the standard. If the water quality does not meet the standard, it is sent to the condensate water tank 9 that does not meet the standard.

[0059] The condensate pressure output by the condensate source 2 102 is less than 0.6MPa and greater than or equal to 0.1MPa. This part of the condensate first enters the ORC power generation module 4 for power generation, lithium bromide refrigeration or equipment drying, etc. After heat exchange, the temperature is reduced to below 110°C for the first waste heat utilization. The cooled condensate passes through the iron and oil removal filter 5, and then passes through the water quality online detection module 6 for water quality detection. If the water quality meets the standard, it is sent to the condensate tank 10 that meets the standard. If the water quality does not meet the standard, it is sent to the condensate tank 9 that does not meet the standard.

[0060] The condensate pressure output by condensate source three 103 is less than 0.1MPa. This part of condensate passes through the iron and oil removal filter 5 and then passes through the water quality online detection module 6 for water quality detection. If the water quality meets the standard, it is sent to the condensate tank 10 that meets the standard. If the water quality does not meet the standard, it is sent to the condensate tank 9 that does not meet the standard.

[0061] A pipeline 6 19 is connected between the qualified condensate tank 10 and the deaerator 3. A group of water quality online detection modules 6, a flow meter 7, and a qualified condensate pump 20 are installed in the middle of the pipeline 6 19, which are respectively used to detect the flow rate and water quality of the condensate in the pipeline and pump the condensate. The condensate stored in the qualified condensate tank 10 is tested for water quality and temperature again, and when the temperature is within the range of 80°C to 90°C, it is pumped to the deaerator 3 through the qualified condensate pump 20 for the second waste heat utilization.

[0062] Please see attached Figure 6 The desalted water station water tank 23 includes a desalted water station raw water tank 2301, a desalted water station ultrafiltration water tank 2302 and a desalted water station primary RO water tank 2303. The outlet of the substandard condensed water tank 9 is connected to the desalted water station water tank 23 via a pipeline 21, and a group of temperature sensors 17, an online water quality detection module 6, a substandard condensed water pump 22 and an electric regulating valve 8 are installed in the middle of the pipeline 21, which are respectively used for the temperature and water quality of the condensed water in the pipeline and the pumping and flow direction control of the condensed water in the pipeline. The substandard condensed water entering the substandard condensed water tank 9 is detected by the temperature sensor 17 and the online water quality detection module 6 to detect its temperature and water quality, and is sent to the desalted water station raw water tank 2301, the desalted water station ultrafiltration water tank 2302 and the desalted water station primary RO water tank 2303 according to the water quality and temperature.

[0063] The system also includes a bypass heat exchanger 11, which is connected to the ORC power generation module 4. The condensate output from the condensate source 2 102 enters the bypass heat exchanger 11 and is connected to the pipeline 3 14. The inlet end of the qualified condensate tank 10 is also connected to the pipeline 5 16, and the other end of the pipeline 5 16 is connected to the external desalted water. The middle part of the pipeline 5 16 is connected with two loops, one of which passes through the middle part of the bypass heat exchanger 11, and the other passes through the middle part of the substandard condensate tank 9. The pipeline 5 16 and the middle part of its loop are equipped with multiple groups of electric regulating valves 8. The pipeline 5 16 is equipped with a group of water quality online detection modules 6 and flow meters 7 near the desalted water replenishment end, which are respectively used to detect the water quality and flow rate of the desalted water replenishment.

[0064] A hot water coil is set inside the substandard condensate tank 9, and the demineralized water is replenished with substandard condensate for heat exchange in the hot water coil, which increases the demineralized water replenishment temperature and reduces the substandard condensate temperature. Ensure the temperature requirement of substandard condensate returning to the demineralized water station

[0065] When the water temperature of the substandard condensate tank 9 exceeds 50°C, consider sending desalted water to the bottom coil of the substandard condensate tank 9 for heat exchange, absorbing the heat of the substandard condensate, and controlling the temperature of the desalted water tank within the range of 80°C to 90°C. Then, it is pumped to the deaerator 3 through the qualified condensate pump 20 for the third waste heat utilization.

[0066] A centralized heating condensate recovery optimization control method comprises the following steps:

[0067] S1. Condensate pressure judgment, high-pressure condensate enters the flash tank 2 from the condensate source 101 for flash evaporation, the steam pressure output from the steam outlet of the flash tank 2 is 0.3MPa, the liquid after flash evaporation enters the ORC power generation module 4, the steam in the flash evaporation enters the deaerator 3 and the steam user through the pipeline 12, medium-pressure condensate enters the ORC power generation module 4 from the condensate source 102, and is classified according to the pressure of the condensate into at least three categories: high, medium and low. Condensate at different pressures is not mixed, and different condensate waste heat utilization facilities are used separately. The high, medium and low pressure condensate pressures are judged to be 0.6MPa and 0.1MPa. High-pressure water is greater than or equal to 0.6MPa, and low-pressure water is less than 0.1MPa;

[0068] S2. Condensate water quality detection. The condensate discharged from the ORC power generation module 4 and the condensate entering the condensate source 103 are detected by the water quality online detection module 6. The qualified condensate enters the qualified condensate tank 10, and the unqualified condensate enters the unqualified condensate tank 9;

[0069] S3. The supplementary desalted water source enters the interior of the condensing water tank 10 after the water quality is tested by the online water quality detection module 6;

[0070] S4. The condensed water in the condensed water tank 10 that meets the standard is tested again and enters the deaerator 3 after meeting the temperature requirement. The condensed water in the condensed water tank 9 that does not meet the standard is discharged to the desalted water station tank 23.

[0071] Starting from the source of condensate, different condensate is classified: classification parameters include: condensate pressure P, condensate temperature T, condensate quality (conductivity, silica, oil content, iron content). After industrial steam is used for indirect heating, condensate is usually in a saturated water state, and after being drained by a mechanical steam trap, the subcooling ΔT is less than 5°C (that is, the condensate temperature is lower than the saturated water temperature under the pressure, but the temperature difference is within 5°C). Therefore, it can be considered that the condensate pressure P and the condensate temperature T are interrelated parameters.

[0072] It can be expressed by formula.

[0073] T=F(P)-ΔT

[0074] For the recovery of condensate, the method of first recovering the waste heat of condensate and then recovering the condensate is adopted. For the central heating boiler, taking the atmospheric thermal deaerator as an example, the ideal state during normal operation is: the deaerator feed water temperature is 80℃~90℃, and a part of steam (0.3MPa) needs to enter the deaerator for deoxidation, and the temperature is heated to 104℃.

[0075] When the temperature is lower than 80℃, more steam is consumed, which increases the deaerator operation cost. When the temperature is higher than 90℃, the deaerator inlet steam is too small, resulting in insufficient pressure in the deaerator, and air from the atmosphere may enter the deaerator, thus affecting the deaerator effect.

[0076] When the deaerator inlet water temperature meets 80℃~90℃ and the waste heat quality of condensate is sufficient, and sufficient flash steam is produced for deaerator deoxygenation, if the waste heat resources are still abundant, ORC power generation, lithium bromide refrigeration or drying should be considered. ORC power generation is preferred because the electricity generated by ORC power generation can be used to save self-consumption electricity or be connected to the power grid, while the heating and cooling demand is not stable.

[0077] Please refer to the attached Figure 4 When the temperature is less than 80°C, reduce the flow to the ORC power generation module and increase the opening of the valve to the bypass heat exchanger 11. When the temperature is greater than 80°C but less than 90°C, maintain the flow to the ORC power generation module and maintain the opening of the valve to the bypass heat exchanger 11. When the temperature is greater than 90°C, increase the flow to the ORC power generation module and reduce the opening of the valve to the bypass heat exchanger 11.

[0078] According to the pressure of condensate, it is classified into at least three categories: high, medium and low. Condensate at different pressures is not mixed, and different condensate waste heat utilization facilities are used separately. The pressure of high, medium and low pressure condensate is judged as 0.6MPa and 0.1MPa. 0.6MPa or more is high pressure water, and less than 0.1MPa is low pressure water.

[0079] Secondly, the quality of condensate water is classified. According to the specification requirements, the following parameters need to be measured;

[0080] Standard concentration = standard concentration × 0.8

[0081] Conductivity. According to different boiler parameters, the data in the table × 0.8 is used as the control parameter. If it is lower than the control parameter, it meets the standard, and if it is higher than the control parameter, it does not meet the standard.

[0082] Silicon dioxide. According to different boiler parameters, the data in the table × 0.8 is used as the control parameter. If it is lower than the control parameter, it is up to standard, and if it is higher than the control parameter, it is not up to standard.

[0083] Full iron. According to different boiler parameters, the data in the table × 0.8 is used as the control parameter. If it is lower than the control parameter, it is up to standard, and if it is higher than the control parameter, it is not up to standard.

[0084] Oil. According to different boiler parameters, the data in the table × 0.8 is used as the control parameter. If it is lower than the control parameter, it is up to standard, and if it is higher than the control parameter, it is not up to standard.

[0085] Hardness. According to different boiler parameters, the data in the table × 0.8 is used as the control parameter. If it is lower than the control parameter, it meets the standard, and if it is higher than the control parameter, it does not meet the standard.

[0086] Standard according to the attached Figure 7 and attached Figure 8 Take control.

[0087] Regarding water quality measurement, the above five parameters, conductivity, total iron and oil can be detected in real time; hardness and silica are measured online at a minimum interval of 15 minutes.

[0088] Conductivity, total iron and oil can be tested in real time, with one data read per minute. If only one or less of the 15 data exceeds the standard, these data are considered to meet the standard.

[0089] It takes 15 minutes to test hardness and silica once. If this data meets the standard, then the data for this 15-minute test is considered to meet the standard. If this data does not meet the standard, then both data are considered to not meet the standard.

[0090] Please see attached Figure 3 In order to maximize the recovery of condensate and meet the water quality requirements, the boiler feed water entering the system at the same time is divided into three categories: qualified condensate, unqualified condensate, and demineralized water. Qualified condensate can directly enter the qualified condensate tank, and unqualified condensate and demineralized water are considered as a whole in calculation, and the water volume and concentration of the measured data are calculated uniformly. The calculation formula is as follows:

[0091] x1=(m1*Q1+m2*Q2) / (m1+m2)

[0092] Among them, x1 represents the calculated concentration of unqualified condensate after mixing with desalted water make-up water, m1 represents the mass flow rate of unqualified condensate; Q1 represents the measured concentration of the unqualified parameter of unqualified condensate; m2 represents the mass flow rate of desalted water make-up water; Q1 represents the measured concentration of the parameter corresponding to the desalted water make-up water.

[0093] It should be noted that in this step, if two indicators are unqualified, the unqualified condensate water needs to be mixed with desalted water before data measurement. It is qualified only when both indicators are qualified. If one indicator is qualified and the other is unqualified, it is also unqualified. Similarly, if three indicators are unqualified, the three mixed indicators need to be remeasured and all of them are qualified to be judged as qualified.

[0094] The condensate water quality is divided into three working conditions: the condensate water quality meets the standard. After calculation, the water quality after mixing with demineralized water meets the standard. After calculation, the water quality after mixing with demineralized water does not meet the standard.

[0095] If the quality of the condensate water meets the standards, the water will directly enter the qualified condensate water tank.

[0096] The quality of the condensate water did not meet the standard, but through calculation, the water quality after mixing with desalted water met the standard and also entered the qualified condensate tank.

[0097] If the condensate water quality does not meet the standard, and after calculation, the water quality after mixing with desalted water still does not meet the standard, it will enter the unqualified condensate tank.

[0098] Please see attached Figure 6 , and finally the utilization of unqualified condensate water.

[0099] Regarding the utilization of unqualified condensate, it is considered to first utilize the waste heat of unqualified condensate and then recycle the unqualified condensate. There are two reasons:

[0100] Waste heat can be utilized to improve the thermal efficiency of the system.

[0101] Unqualified condensate water needs to be returned to the raw water system, and the water temperature is required to be ≤40°C. According to the water quality of unqualified condensate water, consider entering the process section of the raw water system.

[0102] The following are embodiments of using the above-described condensate recovery control system and method.

[0103] Embodiment 1:

[0104] A central heating project has a 90t / h medium-temperature and sub-high-pressure boiler (5.3MPa(g), 450℃) with three condensate lines: the parameters are as follows:

[0105] The first condensate line has a pressure of 0.8 MPa(g), a temperature of 175°C, and a condensate volume of 42 t / h.

[0106] The second condensate line, pressure: 0.4MPa(g), temperature: 151℃, condensate volume: 15t / h.

[0107] The third condensate, pressure: 0.1MPa(g), temperature: 120℃, condensate volume: 10t / h.

[0108] 2. Application of the first-level waste heat utilization

[0109] The first condensate enters the flash tank 1 first, and the steam parameters after flash are: 0.3MPa(g), 143℃, and the flash steam volume Q1 steam:

[0110] Q1 steam = 42 × (h1-h2) / (H2-h2)

[0111] Wherein, h1: high pressure condensation water enthalpy value; 0.8MPa(g) condensation water enthalpy value is 731.5kJ / kg;

[0112] h2: low pressure condensation water enthalpy value; 0.3MPa(g) condensation water enthalpy value is 597.7kJ / kg;

[0113] H2: low pressure steam enthalpy. 0.3MPa(g) saturated steam enthalpy is 2738.1J / kg

[0114] So Q1 steam = 42 × (731.5-597.7) / (2738.1-597.7) = 2.6 t / h;

[0115] The parameters of condensed water after flash evaporation are: 0.3MPa(g), 143℃, and the amount of condensed water after flash evaporation is Q1:

[0116] Q1 condensation = 42 - Q1 evaporation

[0117] Therefore, Q1 condensate = 42-2.6 = 39.4t / h.

[0118] The flash steam produced by the first condensate is sent to the deaerator 4 for thermal deoxygenation. The low-pressure condensate produced and the second condensate enter the ORC power generation evaporator 2 respectively. The heat of the condensate is used to heat the organic Rankine medium (high pressure and low temperature, taking R245fa as an example) in the ORC power generation evaporator. The organic Rankine medium changes from liquid to gas after heating, and does work in the turbine to drive the generator to generate electricity. The exhaust steam after work is cooled by circulating water. The cooled organic Rankine medium enters the evaporation heat exchange surface again under the push of the working fluid pump, realizing a thermal cycle. In the evaporator, the condensate is further cooled, and the temperature drops to below 110°C after cooling. The cooling water situation is as follows:

[0119] The first condensate, 39.4t / h, 0.3MPa(g), 143℃;

[0120] The second condensate water, 15t / h, 0.4MPa(g), 151℃.

[0121] Please refer to the attached diagram of the hot water ORC power generation process system. Fig. 9 .

[0122] Considering the different qualities of the two condensate waters, two evaporators are set up during the heat exchange process, and the two condensate waters after passing through the evaporators enter the next stage respectively. Preliminary calculations show that in this example, the ORC power generation installed power is about 300kW and the net output power is about 200kW.

[0123] The three-way condensate situation is as follows:

[0124] The first condensate, 39.4t / h, 0.3MPa(g), 110℃;

[0125] The second condensate water, 15t / h, 0.4MPa(g), 110℃.

[0126] The third condensate water, 10t / h, 0.1MPa(g), 120℃.

[0127] After water quality monitoring, assuming that the water quality of all three routes meets the standards, the condensate water from all three routes will be sent to the qualified condensate water tank.

[0128] According to calculations, the boiler feed water volume required for the 90t / h boiler in this project is 117t / h (including boiler blowdown water, cooling water, etc.). Then, the desalted water feed volume is:

[0129] M desalination = 117-39.4-15-10 = 52.6 t / h.

[0130] Then the mixed boiler feed water temperature is ≈(39.4×110+15×110+10×120+52.6×20) / 117=70.4℃

[0131] At this time, since the boiler feed water temperature is lower than 80℃~90℃, the feed water temperature is not in an optimal temperature range, and additional deoxygenated steam is required. Therefore, it is considered to send the highest temperature water source to the ORC power generation bypass heat exchanger 12, and increase the temperature of the desalted water to 80℃~90℃ by heat exchange with the desalted water. After heat exchange, the condensate water temperature is reduced to 110℃, which meets the requirements of entering the iron removal and oil removal filter.

[0132] According to the calculation, based on the deaerator feed water temperature of 90°C, in order to achieve a deaerator operating temperature of 104°C, the amount of low-pressure steam required is:

[0133] M deoxygenated steam = 117 × (104-90) × 4.18 / (2738.1-434.72) ≈ 3.0 t / h.

[0134] In this example, the flash steam produced is 2.6 t / h, so the flash steam can be used for deoxidation in the deaerator. The insufficient steam is provided by the thermal system.

[0135] The deaerator feed water temperature meets the requirement of 80℃~90℃.

[0136] Embodiment 2:

[0137] A central heating project has a 90t / h medium-temperature and sub-high-pressure boiler (5.3MPa(g), 450℃) with two condensate lines: the parameters are as follows:

[0138] The first condensate line has a pressure of 0.4 MPa(g), a temperature of 151°C, and a condensate volume of 15 t / h.

[0139] Second condensate, pressure: 0.1MPa(g), temperature: 120℃, condensate volume: 10t / h.

[0140] After analysis, it is known that the total condensate of the first and second condensate is 25t / h. On the premise of confirming that the water quality meets the standard, we should first ensure that the feed water temperature of the deaerator can meet 80℃~90℃.

[0141] Considering that the water volume required for boiler feed water is 117t / h (including boiler blowdown water, cooling water, etc.), the water volume for desalted water is:

[0142] M desalination = 117-15-10 = 92 t / h.

[0143] The mixed boiler feed water temperature is ≈(15×151+10×120+92×20) / 117=45°C.

[0144] Under this condition, even if the deaerator's feed water temperature absorbs all the heat of the condensed water, it can only raise the mixed boiler feed water temperature to 45°C. Therefore, the best way to use it is:

[0145] The first condensate passes through the ORC power generation bypass heat exchanger 12 and the second condensate enters the qualified condensate tank respectively, and then is pumped to the boiler deaerator through the condensate pump.

[0146] Embodiment 3:

[0147] A certain centralized heating project has a 90t / h medium-temperature and sub-high-pressure boiler (5.3MPa(g), 450℃), and the deaerator feed water temperature meets the requirement of 80℃~90℃.

[0148] The first condensate line has a pressure of 0.8 MPa(g), a temperature of 175°C, and a condensate volume of 60 t / h.

[0149] The first condensate enters the flash tank 1 first, and the steam parameters after flash are: 0.3MPa(g), 143℃, and the flash steam volume Q1 steam:

[0150] Q1 steam = 60 × (h1-h2) / (H2-h2)

[0151] Wherein, h1: high pressure condensation water enthalpy value; 0.8MPa(g) condensation water enthalpy value is 731.5kJ / kg;

[0152] h2: low pressure condensation water enthalpy value; 0.3MPa(g) condensation water enthalpy value is 597.7kJ / kg;

[0153] H2: low pressure steam enthalpy. 0.3MPa(g) saturated steam enthalpy is 2738.1J / kg

[0154] So Q1 steam = 60 × (731.5-597.7) / (2738.1-597.7) = 3.8 t / h;

[0155] According to the calculation, based on the deaerator feed water temperature of 90°C, in order to achieve a deaerator operating temperature of 104°C, the amount of low-pressure steam required is:

[0156] Qdeoxygenated steam = Qcondensate × (Tdeoxygenation - Tfeed water) × 4.18 / (Hdeoxygenated steam - Hdeoxygenated water) ≈ 3.0 t / h.

[0157] Q deoxygenated steam = 117 × (104-90) × 4.18 / (2738.1-434.72) ≈ 3.0 t / h.

[0158] In this example, the flash steam produced is 3.8 t / h, so the flash steam volume is higher than the deaerator deoxidation steam volume.

[0159] At this time, according to the attached Figure 5 , reduce the deaeration feed water temperature by increasing the hot water flow to ORC power generation and reducing the valve opening of the ORC bypass heat exchanger. In this way, the deaeration steam required by the deaerator is increased to 3.8t / h. At the same time, due to the increase in the hot water flow to ORC power generation, the ORC power generation will increase.

[0160] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A centralized heating condensate recovery optimization control system, characterized in that: include, A condensate source (1), used for providing a condensate source; A flash tank (2) for generating low-pressure flash steam; A deaerator (3) for removing dissolved oxygen from the thermal system; The ORC power generation module (4) is connected to the condensate source (1) to generate electricity; A substandard condensed water tank (9), used for storing substandard condensed water; A qualified condensed water tank (10) for storing qualified condensed water; The desalted water station water tank (23) is used to store desalted water with different requirements.

2. The centralized heating condensate recovery optimization control system according to claim 1 is characterized in that: The condensate source (1) comprises a condensate source 1 (101), a condensate source 2 (102) and a condensate source 3 (103), which are respectively used to provide condensate of different pressures. The outlet end of the condensate source 1 (101) is connected to a pipeline 1 (12), and the flash tank (2) and the deaerator (3) are connected through the pipeline 1 (12). The flash tank (2) is connected to the ORC power generation module (4). The condensate source 2 (102) is connected to the ORC power generation module (4). ), the condensate source three (103) is connected to the substandard condensate tank (9) and the standard condensate tank (10) through the pipeline four (15), and a temperature sensor (17), a pressure sensor (18) and a flow meter (7) are installed on the side of the ORC power generation module (4) close to the condensate source two (102), the side of the flash tank (2) close to the condensate source one (101), and the side of the pipeline four (15) close to the condensate source three (103).

3. The centralized heating condensate recovery optimization control system according to claim 1 is characterized in that: The outlet end of the ORC power generation module (4) is connected to pipeline 2 (13) and pipeline 3 (14), and pipeline 2 (13) and pipeline 3 (14) are respectively connected to a substandard condensate water tank (9) and a standard condensate water tank (10), and electric regulating valves (8) are installed at the three-way joints of pipeline 2 (13) and pipeline 3 (14).

4. The centralized heating condensate recovery optimization control system according to claim 3 is characterized in that: A set of iron and oil removal filters (5), an online water quality detection module (6) and a flow meter (7) are installed in the middle of the pipeline 2 (13), the pipeline 3 (14) and the pipeline 4 (15), which are respectively used for filtering the condensed water, detecting the water quality and detecting the flow rate.

5. The centralized heating condensate recovery optimization control system according to claim 1 is characterized in that: A pipeline six (19) is connected between the qualified condensate tank (10) and the deaerator (3), and a group of water quality online detection modules (6), a flow meter (7), and a qualified condensate pump (20) are installed in the middle of the pipeline six (19), which are respectively used to detect the flow rate and water quality of the condensate in the pipeline and to pump the condensate.

6. The centralized heating condensate recovery optimization control system according to claim 1 is characterized in that: The desalted water station water tank (23) comprises a desalted water station raw water tank (2301), a desalted water station ultrafiltration water tank (2302) and a desalted water station primary RO water tank (2303); an outlet on one side of the substandard condensed water tank (9) is connected to the desalted water station water tank (23) via a pipeline seven (21); and a group of temperature sensors (17), a water quality online detection module (6), a substandard condensed water pump (22) and an electric regulating valve (8) are installed in the middle of the pipeline seven (21), which are respectively used for the temperature and water quality of the condensed water in the pipeline and the pumping and flow direction control of the condensed water in the pipeline.

7. The centralized heating condensate recovery optimization control system according to claim 2 is characterized in that: The system also includes a bypass heat exchanger (11), which is connected to the ORC power generation module (4). The condensate output from the second condensate source (102) enters the bypass heat exchanger (11) and is connected to the pipeline three (14). The inlet end of the qualified condensate tank (10) is also connected to the pipeline five (16). The other end of the pipeline five (16) is connected to external desalted water. The middle of the pipeline five (16) is connected to two loops, one of which passes through the middle of the bypass heat exchanger (11) and the other passes through the middle of the substandard condensate tank (9). The pipeline five (16) and the middle of its loops are equipped with multiple groups of electric regulating valves (8). The pipeline five (16) is equipped with a group of water quality online detection modules (6) and flow meters (7) near the desalted water replenishment end, which are respectively used to detect the water quality and flow rate of the desalted water replenishment.

8. A method for optimizing the recovery of condensate from central heating, characterized in that: A centralized heating condensate recovery optimization control system applied to any one of claims 1 to 7 comprises the following steps: S1. Determination of condensate pressure. High-pressure condensate enters the flash tank (2) from condensate source 1 (101) for flash evaporation. The liquid after flash evaporation enters the ORC power generation module (4). The steam in the flash evaporation enters the deaerator (3) and the steam user through pipeline 1 (12). Medium-pressure condensate enters the ORC power generation module (4) from condensate source 2 (102). S2. Condensate water quality detection. The condensate discharged from the ORC power generation module (4) and the condensate entering the condensate source three (103) are subjected to water quality detection and judgment by the water quality online detection module (6). The qualified condensate enters the qualified condensate water tank (10), and the unqualified condensate enters the unqualified condensate water tank (9); S3. The supplementary desalted water source enters the qualified condensing water tank (10) after the water quality is tested by the online water quality detection module (6); S4. The condensed water in the condensed water tank (10) that meets the standard is tested again and enters the deaerator (3) after meeting the temperature requirements. The condensed water in the condensed water tank (9) that does not meet the standard is discharged to the desalted water station tank (23).

9. A centralized heating condensate recovery optimization control method according to claim 8, characterized in that: The judgment pressures of high, medium and low pressure condensate water are 0.6MPa and 0.1MPa. 0.6MPa or more is high pressure water, and less than 0.1MPa is low pressure water.

10. A centralized heating condensate recovery optimization control method according to claim 9, characterized in that: The steam output pressure at the steam outlet of the flash tank (2) is 0.3 MPa.

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