A control system for low pressure steam reuse

Abstract

The utility model discloses a kind of control systems of low-pressure steam recycling, it is related to low-pressure steam utilization technical field;Purpose is to utilize the surplus steam outside steel plant to carry out heat exchange to the condensate water in plant, and the following technical scheme is proposed: including low-pressure steam heat exchanger, the inlet end of low-pressure steam heat exchanger is connected with condensate water system in plant and low-pressure steam system outside plant respectively, and the outlet end of low-pressure steam heat exchanger is connected with deaerator and drain recovery system respectively;Low-pressure steam heat exchanger condensate water inlet end is equipped with inlet water side electric valve, low-pressure steam heat exchanger condensate water outlet end is equipped with outlet water side electric valve, and bypass electric valve, which is arranged in parallel with low-pressure steam heat exchanger, is also provided on condensate water pipeline;Control regulating valve and low-pressure steam inlet electric shut-off valve are arranged in series on steam pipeline outside plant.The utility model has the advantages of efficient heat exchange, heat recovery, steam quality optimization and utilization, water resource recycling, energy consumption reduction and the like.

Description

Technical Field

[0001] This utility model relates to the field of low-pressure steam utilization technology, and specifically to a control system for low-pressure steam reuse. Background Technology

[0002] Currently, steel companies still face problems such as overcapacity, excessive energy consumption, and a severe decline in profits and efficiency. To reduce resource consumption and environmental pollution, and save on production costs, steel companies need more refined management, upgraded equipment, optimized and transformed process technology systems, and innovation to increase efficiency and create new economic growth points.

[0003] In the metallurgical process, steel plants generate some surplus steam, such as sintering waste heat steam and rolling waste heat steam. In most cases, this steam is directly discharged, resulting in energy loss and environmental pollution. Characteristics of steam in steel enterprises include: low steam grade, fluctuating steam parameters and flow rates, unstable seasonal supply and demand, and low utilization efficiency of steam by existing enterprises.

[0004] Chinese utility model patent CN206291194U provides a gas-fired power generation system based on the optimized utilization of saturated steam from a steel plant. The system includes at least a superheater and an economizer in the gas boiler. Superheated steam from the superheater enters a steam turbine, which drives the generator. The turbine exhaust steam enters a condenser and condenses into condensate. The condensate is pressurized by a condensate pump and sequentially sent to a flue gas-condensate heat exchanger, a low-pressure steam-condensate heat exchanger, a deaerator, and a medium-pressure steam-condensate heat exchanger for heating. Finally, the condensate returns to the gas boiler, completing the entire steam-water system cycle. The flue gas-condensate heat exchanger utilizes the residual heat from the low-temperature flue gas at the tail end of the gas boiler for primary heating of the condensate. The low-pressure steam and medium-pressure steam-condensate heat exchangers utilize the low-pressure and medium-pressure saturated steam from the steel plant, respectively, to further heat the condensate. This cascaded utilization of thermal energy achieves scientific energy use.

[0005] Therefore, considering the characteristics of the steel plant's production process system, the properties of low-pressure steam, the energy utilization efficiency of the steel plant's process system, and the economic benefits of the steel plant, it is particularly important to comprehensively utilize surplus steam in steel plants to save energy, improve efficiency, and optimize process technology systems. It is necessary to establish a low-pressure steam utilization scheme and operation control system for steel plants to address existing production process systems and improve efficiency. Utility Model Content

[0006] The purpose of this invention is to provide a control system for the reuse of low-pressure steam, so as to use surplus steam outside the steel plant to exchange heat with the condensate inside the plant.

[0007] The technical solution of this utility model to solve the above-mentioned technical problems is as follows:

[0008] A control system for low-pressure steam reuse includes an in-plant condensate system and a condensate pipeline connected to the outlet end of the in-plant condensate system. The condensate pipeline includes a first condensate pipeline and a second condensate pipeline. The first condensate pipeline is connected to the condensate inlet end of a low-pressure steam heat exchanger via a heat exchanger inlet pipe, and the second condensate pipeline is connected to the condensate outlet end of the low-pressure steam heat exchanger via a heat exchanger outlet pipe. The outlet end of the second condensate pipeline is connected to a deaerator, and the deaerator is connected to the in-plant condensate system via a circulation pipeline.

[0009] The low-pressure steam heat exchanger includes a steam passage and a fluid passage. The steam passage has a steam inlet end and a condensate outlet end. The steam inlet end is connected to an external low-pressure steam system through an external steam pipeline. A control regulating valve and an electric shut-off valve for the low-pressure steam inlet are connected in series on the external steam pipeline. The two ends of the fluid passage are connected to the heat exchanger inlet pipe and the heat exchanger outlet pipe, respectively.

[0010] An inlet water side electric valve is provided on the heat exchanger inlet pipe, and an outlet water side electric valve is provided on the heat exchanger outlet pipe. A first bypass branch is connected between the inlet end of the heat exchanger inlet pipe and the outlet end of the heat exchanger outlet pipe. A bypass electric valve for switching the direction of condensate flow is provided on the first bypass branch.

[0011] Furthermore, a three-way diverter valve for adjusting the condensate flow direction is installed between the heat exchanger outlet pipe, the second condensate pipe and the first bypass branch.

[0012] Furthermore, a steam buffer tank is installed on the pipeline between the external low-pressure steam system and the low-pressure steam inlet electric shut-off valve to remove moisture and impurities from the steam.

[0013] Furthermore, a steam-water separator is installed on the pipeline between the steam buffer tank and the external low-pressure steam system to separate water droplets from the steam.

[0014] Furthermore, the condensate pipeline also includes a third condensate pipeline. A low-pressure heater is installed between the third condensate pipeline and the first condensate pipeline. The inlet end of the third condensate pipeline is connected to the plant's condensate system, and the outlet end of the third condensate pipeline is connected to the low-pressure heater through the heater inlet pipe. The inlet end of the first condensate pipeline is connected to the low-pressure heater through the heater outlet pipe. Both the heater inlet pipe and the heater outlet pipe are equipped with electric shut-off valves.

[0015] Furthermore, a second bypass branch is connected between the inlet end of the heater inlet pipe and the outlet end of the heater outlet pipe, and a bypass shut-off valve for switching the direction of condensate flow is provided on the second bypass branch.

[0016] Furthermore, a condensate recovery system is provided at the condensate outlet end for recovering the condensate generated during the heat exchange process.

[0017] Furthermore, the condensate recovery system includes a normal condensate drain line and an emergency condensate drain line connected in parallel at the condensate outlet. The normal condensate drain line is connected to the condensate tank via an expansion container, and the emergency condensate drain line is directly connected to the condensate tank. The outlet of the condensate tank is connected to an external water recovery system.

[0018] Furthermore, a condensate pump is installed on the pipeline between the condensate tank and the off-site water recycling system.

[0019] Furthermore, a first manual shut-off valve is installed on the pipeline between the condensate tank and the condensate pump. This invention has the following beneficial effects:

[0020] This invention utilizes a low-pressure steam heat exchanger to achieve effective heat exchange between low-pressure steam and condensate in the plant. The heat from the low-pressure steam is fully transferred to the condensate, raising its temperature and providing hot water at a suitable temperature for subsequent processes such as deoxygenation, thus reducing the consumption of additional heating energy. Simultaneously, a condensate recovery system recovers the condensate generated during the heat exchange process, utilizing the heat within the condensate to a certain extent, further improving the overall energy utilization rate.

[0021] The steam supplied by the external low-pressure steam system is processed by a steam buffer tank and a steam-water separator, effectively removing moisture and impurities and improving steam quality. High-quality steam can transfer heat more efficiently in the heat exchanger, reducing the problem of low heat exchange efficiency caused by poor steam quality, thereby improving the overall system's utilization efficiency of low-pressure steam.

[0022] The condensate recovery system pressurizes the recovered condensate using a condensate pump and transports it to an off-site water collection system, achieving water resource recycling. This reduces the plant's need to purchase fresh water, lowering water costs. By improving the utilization efficiency of low-pressure steam, it reduces the consumption of additional energy (such as fuel and electricity), thereby lowering energy procurement costs. Simultaneously, the efficient heat exchange process reduces energy waste due to heat loss, further reducing production costs. Attached Figure Description

[0023] Figure 1 This is an overall schematic diagram of the control system for low-pressure steam reuse of this utility model;

[0024] Figure 2 This is a schematic diagram of the hydrophobic recovery system.

[0025] Figure 3 This is a schematic diagram showing the connection between a low-pressure steam heat exchanger and piping.

[0026] Figures 1 to 3The reference numerals in the accompanying drawings represent: low-pressure steam heat exchanger 1, inlet water-side electric valve 11, heat exchanger inlet pipe 111, heat exchanger outlet pipe 112, outlet water-side electric valve 12, bypass electric valve 13, three-way diverter valve 14, plant condensate system 2, condensate pipeline, first condensate pipeline 211, second condensate pipeline 212, first bypass branch 213, third condensate pipeline 214, second bypass branch 215, external low-pressure steam system 3, control and regulating valve 31, low-pressure steam... 32. Electric shut-off valve at the inlet; 33. Steam buffer tank; 34. Steam-water separator; 35. External steam pipeline; 4. Drainage recovery system; 41. Normal drainage pipeline; 42. Emergency drainage pipeline; 43. Drainage tank; 44. Drainage pump; 45. First manual shut-off valve; 46. Check valve; 47. Second manual shut-off valve; 48. Expansion tank; 5. Low-pressure heater; 51. Electric shut-off valves on the inlet and outlet water sides; 511. Heater inlet pipe; 512. Heater outlet pipe; 52. Bypass shut-off valve; 6. Deaerator; 7. External water recovery system. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0028] In this utility model, the terms "longitudinal," "lateral," "vertical," "upper," "lower," "front," "rear," "left," "right," "top," and "bottom," etc., indicate the orientation or positional relationship based on the appendix. Figure 2 The orientation or positional relationship shown is for the purpose of describing the present invention only, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0029] Please refer to Figure 1-3 In the steel production process, low-pressure steam is an important form of energy, and its effective utilization is of great significance for improving energy efficiency, reducing production costs, and minimizing environmental pollution. This solution aims to elaborate on the implementation method of a control system for low-pressure steam reuse. This system achieves efficient utilization and stable control of low-pressure steam by rationally designing steam heat exchange, condensate recovery, and condensate treatment processes, and incorporating advanced control strategies. The following is a detailed description of the specific implementation method of this system:

[0030] The low-pressure steam reuse control system of this steel plant includes an in-plant condensate system 2 and condensate pipes connected to the outlet of the in-plant condensate system 2. The condensate pipes include a first condensate pipe 211 and a second condensate pipe 212. The first condensate pipe 211 is connected to the condensate inlet of the low-pressure steam heat exchanger 1 via a heat exchanger inlet pipe 111, and the second condensate pipe 212 is connected to the condensate outlet of the low-pressure steam heat exchanger 1 via a heat exchanger outlet pipe 112. The outlet of the second condensate pipe 212 is connected to a deaerator 6, and the deaerator 6 is connected to the in-plant condensate system 2 via a circulation pipe. The low-pressure steam heat exchanger 1 includes a steam passage and a fluid passage. The passage is equipped with a steam inlet and a condensate outlet. The steam inlet is connected to the external low-pressure steam system 3 via an external steam pipeline 35. A control regulating valve 31 and a low-pressure steam inlet electric shut-off valve 32 are connected in series on the external steam pipeline 35. The two ends of the fluid passage are connected to the heat exchanger inlet pipe 111 and the heat exchanger outlet pipe 112, respectively. An inlet water-side electric valve 11 is provided on the heat exchanger inlet pipe 111, and an outlet water-side electric valve 12 is provided on the heat exchanger outlet pipe 112. A first bypass branch 213 is connected between the inlet end of the heat exchanger inlet pipe 111 and the outlet end of the heat exchanger outlet pipe 112. A bypass electric valve 13 for switching the condensate flow direction is provided on the first bypass branch.

[0031] The plant's condensate system 2 serves as the water source for the entire system, with its outlet connected to a condensate pipeline. The condensate pipeline is divided into a first condensate pipeline 211 and a second condensate pipeline 212. The first condensate pipeline 211 connects to the condensate inlet of the low-pressure steam heat exchanger 1 via a heat exchanger inlet pipe 111. An inlet-side electric valve 11 is installed on the heat exchanger inlet pipe 111 to control the condensate flow rate entering the low-pressure steam heat exchanger 1. The second condensate pipeline 212 connects to the condensate outlet of the low-pressure steam heat exchanger 1 via a heat exchanger outlet pipe 112. An outlet-side electric valve 12 is installed on the heat exchanger outlet pipe 112 to control the condensate flow rate exiting the heat exchanger.

[0032] A first bypass branch 213 is connected between the inlet end of the heat exchanger inlet pipe 111 and the outlet end of the heat exchanger outlet pipe 112. A bypass electric valve 13 is installed on this branch. When the low-pressure steam heat exchanger 1 needs maintenance or malfunctions, the inlet water-side electric valve 11 and the outlet water-side electric valve 12 can be closed, while the bypass electric valve 13 is opened, allowing condensate to flow directly through the bypass branch 213 to downstream equipment, ensuring continuous system operation. The condensate exchanges heat with steam in the fluid pipeline, absorbing heat and increasing in temperature. The condensate after heat exchange flows out through the heat exchanger outlet pipe 112 and enters the subsequent treatment stage. The outlet end of the second condensate pipeline 212 is connected to a deaerator 6, which removes dissolved oxygen from the condensate to prevent equipment corrosion. The deaerator 6 is connected to the plant's condensate system 2 via a circulation pipeline, forming a condensate circulation loop. The condensate treated by deaerator 6 can be returned to the plant's condensate system 2 for recycling, thereby improving water resource utilization efficiency.

[0033] The low-pressure steam heat exchanger 1 is the core component of the system. It contains a steam passage and a fluid passage, which can be arranged using pipes or chambers. The steam passage has a steam inlet and a condensate outlet. The steam inlet is connected to the external low-pressure steam system 3 via an external steam pipeline 35. A control valve 31 and a low-pressure steam inlet electrically operated shut-off valve 32 are connected in series on the external steam pipeline 35. The control valve 31 regulates the steam flow entering the low-pressure steam heat exchanger 1 to meet heat exchange requirements under different operating conditions. The low-pressure steam inlet electrically operated shut-off valve 32 quickly cuts off the steam supply to ensure system safety in the event of system shutdown or abnormal conditions.

[0034] A three-way diverter valve 14 for adjusting the condensate flow direction is installed between the heat exchanger outlet pipe 112, the second condensate pipe 212 and the first bypass branch 213.

[0035] To flexibly control the proportion of condensate flow to the low-pressure steam heat exchanger 1 or the bypass branch 213, a three-way diverter valve 14 is installed at the intersection of the heat exchanger outlet pipe 112, the second condensate pipe 212, and the first bypass branch 213. When more condensate needs to flow to the low-pressure steam heat exchanger 1, the opening of the three-way diverter valve 14 to the low-pressure steam heat exchanger 1 is increased; conversely, the opening of the three-way diverter valve 14 is decreased.

[0036] Furthermore, a steam buffer tank 33 is installed on the pipeline between the external low-pressure steam system 3 and the low-pressure steam inlet electric shut-off valve 32 to remove moisture and impurities from the steam.

[0037] To improve the quality of the steam entering the low-pressure steam heat exchanger 1, a steam buffer tank 33 is installed on the pipeline between the external low-pressure steam system 3 and the low-pressure steam inlet electric shut-off valve 32. The steam buffer tank 33 can stabilize and buffer the steam, reducing the impact of steam pressure fluctuations on the low-pressure steam heat exchanger 1.

[0038] To further remove impurities and water droplets from the steam, a steam-water separator 34 is installed on the pipeline between the steam buffer tank 33 and the external low-pressure steam system 3 to separate water droplets from the steam.

[0039] A steam-water separator 34 is installed on the pipeline between the steam buffer tank 33 and the external low-pressure steam system 3. This separator physically separates water droplets and impurities from the steam, ensuring that the steam entering the steam buffer tank 33 is dry and pure. This prevents the low-pressure steam heat exchanger 1 from becoming less efficient or corroding due to water content in the steam. The steam-water separator 34 and the steam buffer tank 33 work together to ensure stable steam quality entering the low-pressure steam heat exchanger 1. The steam-water separator 34 is regularly maintained and cleaned to ensure its separation effect; the steam buffer tank 33 monitors the steam pressure in real time and maintains the steam pressure within a reasonable range through linkage control with the control regulating valve 31.

[0040] Furthermore, the condensate pipeline also includes a third condensate pipeline 214. A low-pressure heater 5 is installed between the third condensate pipeline 214 and the first condensate pipeline 211. The inlet end of the third condensate pipeline 214 is connected to the plant's condensate system 2, and the outlet end of the third condensate pipeline 214 is connected to the low-pressure heater 5 through a heater inlet pipe 511. The inlet end of the first condensate pipeline 211 is connected to the low-pressure heater 5 through a heater outlet pipe 512. Both the heater inlet pipe 511 and the heater outlet pipe 512 are equipped with an electric shut-off valve 51.

[0041] To further increase the heating efficiency of the condensate, one or more low-pressure heaters 5 are installed between the third condensate pipe 214 and the first condensate pipe 211. The inlet end of the third condensate pipe 214 is connected to the plant's condensate system 2, and the outlet end is connected to the low-pressure heater 5 via the heater inlet pipe 511. The inlet end of the first condensate pipe 211 is connected to the low-pressure heater 5 via the heater outlet pipe 512, and the outlet end is connected to the heater inlet pipe 511. Both the heater inlet pipe 511 and the heater outlet pipe 512 are equipped with electrically operated shut-off valves 51 to control the flow rate of condensate into and out of the low-pressure heater 5.

[0042] Furthermore, a second bypass branch 215 is connected between the inlet end of the heater inlet pipe 511 and the outlet end of the heater outlet pipe 512, and a bypass shut-off valve 52 for switching the direction of condensate flow is provided on the second bypass branch 215.

[0043] The low-pressure heater 5 can utilize other heat sources within the plant to further heat the condensate, increasing its temperature and providing higher-quality thermal energy for subsequent processes. A second bypass branch 215 is connected between the inlet end of the heater inlet pipe 511 and the outlet end of the heater outlet pipe 512, and a bypass shut-off valve 52 is installed on the second bypass branch 215. When the low-pressure heater 5 requires maintenance or malfunctions, the electrically operated shut-off valves 51 on the heater inlet pipe 511 and the heater outlet pipe 512 can be closed, while the bypass shut-off valve 52 is opened, allowing the condensate to flow directly through the second bypass branch 215 to the first condensate pipe 211, preventing the entire system from being affected by a malfunction of the low-pressure heater 5.

[0044] Furthermore, a condensate recovery system 4 is provided at the condensate outlet for recovering the condensate generated during the heat exchange process. The condensate recovery system 4 includes a normal condensate pipe 41 and an emergency condensate pipe 42 connected in parallel at the condensate outlet. The normal condensate pipe 41 is connected to the condensate tank 43 through an expansion container 48, and the emergency condensate pipe 42 is directly connected to the condensate tank 43. The outlet of the condensate tank 43 is connected to an external water recovery system 7.

[0045] During the heat exchange process, the low-pressure steam heat exchanger 1 generates condensate. To recover this condensate, a condensate recovery system 4 is installed at the condensate outlet. The condensate recovery system 4 includes a normal condensate line 41 and an emergency condensate line 42 connected in parallel at the condensate outlet. The normal condensate line 41 and the emergency condensate line 42 work together to ensure that the condensate can be recovered in a timely and safe manner. The condensate tank 43 is periodically monitored for level to prevent overflow. The normal condensate line 41 is connected to the condensate tank 43 through an expansion vessel 48. The expansion vessel 48 can recover and reuse part of the flash steam in the condensate, improving energy efficiency. After the condensate enters the expansion vessel 48, the steam generated by flash evaporation can be further used in other processes, while the remaining condensate flows into the condensate tank 43. The emergency drain pipe 42 is directly connected to the drain tank 43. When the normal drain pipe 41 malfunctions or the drain flow is too large, the drain water can directly enter the drain tank 43 through the emergency drain pipe 42, ensuring the stable operation of the drain recovery system 4.

[0046] Furthermore, a condensate pump 44 is installed on the pipeline between the condensate tank 43 and the off-site water recovery system 7.

[0047] To transport the condensate to the off-site water recycling system 7, a condensate pump 44 is installed on the pipeline between the condensate tank 43 and the off-site water recycling system 7. The condensate pump 44 provides the transport power, enabling the condensate to reach the off-site water recycling system 7 smoothly.

[0048] Furthermore, a first manual shut-off valve 45 is provided on the pipeline between the drain tank 43 and the drain pump 44.

[0049] The first manual shut-off valve 45 can manually cut off the flow of condensate to the condensate pump 44 when the condensate pump 44 is under maintenance or the system is shut down, ensuring operational safety.

[0050] Furthermore, a check valve 46 and a second manual shut-off valve 47 are installed on the pipeline between the drain pump 44 and the off-site water recovery system 7.

[0051] The check valve 46 and the second manual shut-off valve 47 installed on the pipeline between the condensate pump 44 and the external water recovery system 7 ensure the safety and reliability of the condensate recovery process. The expansion tank 48 in the condensate recovery system 4 converts some of the condensate into secondary steam through flash evaporation. This secondary steam can be recovered and reused, further improving energy efficiency. In addition, the condensate recovery system 4 is equipped with a flow meter and a temperature sensor to monitor the flow rate and temperature of the condensate, providing data support for system optimization and adjustment.

[0052] During actual operation, the system flexibly adjusts according to different operating conditions. When the plant requires a large amount of heat energy, the opening of the control valve 31 can be increased to increase the steam flow into the low-pressure steam heat exchanger 1, improve heat exchange efficiency, and allow the condensate to obtain more heat. At the same time, the three-way diverter valve 14 is adjusted to allow more condensate to flow to the low-pressure steam heat exchanger 1 and participate in the heat exchange process. When the low-pressure steam heat exchanger 1 malfunctions or needs maintenance, the electric shut-off valves 51 on the inlet water side 11, the outlet water side 12, the heater inlet pipe 511, and the heater outlet pipe 512 are closed in a timely manner, while the bypass electric valve 13 and the bypass shut-off valve 52 are opened, allowing the condensate to continue flowing through the bypass branch 213 and the second bypass branch 215, ensuring uninterrupted system operation.

[0053] During implementation, the system first provides a stable condensate source through the plant's condensate system 2, which is then transported to the low-pressure steam heat exchanger 1 via condensate pipelines. At the inlet of the low-pressure steam heat exchanger 1, the condensate flow rate is precisely controlled by the inlet water-side electric valve 11, and then it enters the low-pressure steam heat exchanger 1 to exchange heat with low-pressure steam. The low-pressure steam is provided by the external low-pressure steam system 3 and is transported to the inlet of the low-pressure steam heat exchanger 1 via the external steam pipeline 35. During this process, the steam parameters are precisely regulated by the control regulating valve 31 and the low-pressure steam inlet electric shut-off valve 32. The installation of the steam buffer tank 33 and the steam-water separator 34 effectively improves the quality of the steam entering the low-pressure steam heat exchanger 1 and reduces the impact of moisture and impurities on the heat exchange effect. Inside the low-pressure steam heat exchanger 1, steam and condensate achieve heat transfer through a partitioned heat exchange method. After the condensate is heated to the required temperature, it flows out through the outlet water-side electric valve 12 and enters the subsequent processing stage.

[0054] In terms of the operation and control system, this system adopts advanced automated control technology to achieve precise monitoring and intelligent regulation of the entire low-pressure steam utilization process. Specifically, the system uses a PLC (Programmable Logic Controller) as the core control unit to centrally control key valves such as the inlet water-side electric valve 11, the outlet water-side electric valve 12, the bypass electric valve 13, the control regulating valve 31, and the low-pressure steam inlet electric shut-off valve 32. Simultaneously, the system integrates various sensor devices such as pressure sensors, temperature sensors, and level gauges to monitor key parameters such as steam pressure, temperature, condensate flow rate, and the water level in the drain tank 43 in real time. Based on the data feedback from the sensors, the PLC control unit automatically adjusts the opening degree of each valve to ensure stable system operation. Furthermore, the system has fault alarm and recording functions. In the event of a fault, it will immediately issue an audible and visual alarm signal and record information such as the time of occurrence, type, and handling process of the fault, providing strong support for subsequent fault diagnosis and maintenance.

[0055] The components or systems involved in this utility model, such as the low-pressure steam heat exchanger 1, the in-plant condensate system 2, the external low-pressure steam system 3, the condensate recovery system 4, the low-pressure heater 5, the deaerator 6, various valves and pipelines, and the external water recovery system 7, are all conventional structures or systems existing in the field, and their specific structures and working principles are known to those skilled in the art.

[0056] The low-pressure steam reuse control system in this embodiment achieves efficient heat exchange and energy recovery between condensate from the plant and low-pressure steam from outside the plant through the coordinated operation of its components. The system possesses flexible adjustment capabilities and a reliable fault handling mechanism, enabling stable operation under various working conditions and providing an effective technical means for enterprises to save energy and reduce costs. Simultaneously, the system's design and operation fully consider equipment safety and operational reliability; the connections between components are reasonable, operation is simple, and daily management is convenient. In practical applications, the system parameters and configuration can be appropriately adjusted according to the specific needs and production processes of the enterprise to achieve optimal energy utilization.

[0057] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A control system for low-pressure steam reuse, comprising an in-plant condensate system (2) and a condensate pipe connected to the outlet end of the in-plant condensate system (2), characterized in that, The condensate pipeline includes a first condensate pipeline (211) and a second condensate pipeline (212). The first condensate pipeline (211) is connected to the condensate inlet of the low-pressure steam heat exchanger (1) through the heat exchanger inlet pipe (111). The second condensate pipeline (212) is connected to the condensate outlet of the low-pressure steam heat exchanger (1) through the heat exchanger outlet pipe (112). The outlet of the second condensate pipeline (212) is connected to the deaerator (6). The deaerator (6) is connected to the plant's condensate system (2) through a circulation pipeline. The low-pressure steam heat exchanger (1) includes a steam channel and a fluid channel. The steam channel is provided with a steam inlet end and a condensate outlet end. The steam inlet end is connected to the low-pressure steam system (3) outside the plant through an external steam pipeline (35). A control regulating valve (31) and a low-pressure steam inlet electric shut-off valve (32) are connected in series on the external steam pipeline (35). The two ends of the fluid channel are respectively connected to the heat exchanger inlet pipe (111) and the heat exchanger outlet pipe (112). An inlet water side electric valve (11) is provided on the heat exchanger inlet pipe (111), and an outlet water side electric valve (12) is provided on the heat exchanger outlet pipe (112). A first bypass branch (213) is connected between the inlet end of the heat exchanger inlet pipe (111) and the outlet end of the heat exchanger outlet pipe (112). A bypass electric valve (13) for switching the flow direction of condensate is provided on the first bypass branch.

2. The control system for low-pressure steam reuse according to claim 1, characterized in that, A three-way diverter valve (14) for adjusting the condensate flow direction is provided between the heat exchanger outlet pipe (112), the second condensate pipe (212) and the first bypass branch (213).

3. The control system for low-pressure steam reuse according to claim 1, characterized in that, A steam buffer tank (33) is provided on the pipeline between the off-site low-pressure steam system (3) and the low-pressure steam inlet electric shut-off valve (32) to remove moisture and impurities from the steam.

4. The control system for low-pressure steam reuse according to claim 3, characterized in that, A steam-water separator (34) for separating water droplets in steam is provided on the pipeline between the steam buffer tank (33) and the off-site low-pressure steam system (3).

5. The control system for low-pressure steam reuse according to claim 1, characterized in that, The condensate pipeline also includes a third condensate pipeline (214), and a low-pressure heater (5) is provided between the third condensate pipeline (214) and the first condensate pipeline (211). The inlet end of the third condensate pipeline (214) is connected to the plant's condensate system (2), and the outlet end of the third condensate pipeline (214) is connected to the low-pressure heater (5) through the heater inlet pipe (511). The inlet end of the first condensate pipeline (211) is connected to the low-pressure heater (5) through the heater outlet pipe (512). Both the heater inlet pipe (511) and the heater outlet pipe (512) are equipped with electric shut-off valves (51).

6. The control system for low-pressure steam reuse according to claim 5, characterized in that, A second bypass branch (215) is connected between the inlet end of the heater inlet pipe (511) and the outlet end of the heater outlet pipe (512). A bypass shut-off valve (52) for switching the direction of condensate flow is provided on the second bypass branch (215).

7. The control system for low-pressure steam reuse according to any one of claims 1 to 6, characterized in that, The condensate outlet end is equipped with a condensate recovery system (4) for recovering the condensate generated during the heat exchange process.

8. The control system for low-pressure steam reuse according to claim 7, characterized in that, The drainage recovery system (4) includes a normal drainage pipeline (41) and an emergency drainage pipeline (42) connected in parallel at the drainage outlet end. The normal drainage pipeline (41) is connected to the drainage tank (43) through an expansion container (48). The emergency drainage pipeline (42) is directly connected to the drainage tank (43). The outlet end of the drainage tank (43) is connected to the off-site water recovery system (7).

9. The control system for low-pressure steam reuse according to claim 8, characterized in that, A condensate pump (44) is installed on the pipeline between the condensate tank (43) and the off-site water recovery system (7).

10. The control system for low-pressure steam reuse according to claim 9, characterized in that, A first manual shut-off valve (45) is provided on the pipeline between the condensate tank (43) and the condensate pump (44).

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