Condensate water recovery and treatment unit with temperature and pressure regulation

Abstract

The present application relates to the technical field of condensate water treatment, and discloses a condensate water recovery treatment unit with temperature and pressure regulation, which comprises a condensate water tank provided with a collecting cavity and a temperature and pressure regulation cavity; the collecting cavity is provided with a condensate water inlet, a safety valve, a pressure transmitter, a liquid level meter and a liquid level lifting device; a water-water heat exchanger is arranged in the temperature and pressure regulation cavity; a flow guide and pressure boosting device is arranged in the water-water heat exchanger and connected to the inlets of at least two water pumps; the outlets of the water pumps are connected to a check valve, a pressure regulating valve and a condensate water outlet in sequence; a plurality of pressure sensors and temperature sensors are arranged between the water pumps and the condensate water tank; a PLC control cabinet limits the operating pressure of the water pumps; the start-stop strategy of the standby water pumps and the operating time window of the water pumps are dynamically adjusted; and the opening degrees of the temperature control regulating valve and the pressure regulating valve are adjusted in real time. The present application solves the cavitation problem caused by space limitation, improves the heat exchange efficiency, control accuracy and intelligent level.

Description

Technical Field

[0001] This invention relates to the field of condensate treatment technology, and more specifically, to a condensate recovery and treatment unit with temperature and pressure regulation. Background Technology

[0002] Condensate recovery and treatment systems are a crucial component of industrial steam energy management, widely used in high-energy-consuming industries such as petrochemicals, power generation, metallurgy, and pharmaceuticals. The main function of this system is to collect, cool, and pressurize condensate from the thermal system before returning it to the boiler or heat exchange equipment, thereby improving the efficiency of water and heat energy recycling and reducing energy consumption and operating costs. In practical engineering applications, especially in skid-mounted or closed-loop recovery systems with limited installation height, the inability to position the condensate tank at a high level results in insufficient net positive suction head (NPSH) at the pump inlet. This leads to localized cavitation of the condensate under the high-speed rotation of the pump impeller, causing excessive pump noise, strong vibration, shortened service life, and in severe cases, even system shutdown. Furthermore, traditional systems generally employ fixed-logic pressure or level control methods, failing to intelligently switch between the main and standby pumps based on real-time operating conditions. This results in frequent pump start-ups and shutdowns, large start-up and shutdown current surges, and system instability. On the other hand, traditional condensate heat exchange control methods typically only control temperature as a single variable, failing to consider the interconnected impact of condensate temperature changes on system pressure fluctuations. This makes it impossible to dynamically maintain the stable state of "slight subcooling + slight positive pressure" at the pump inlet, and the cavitation problem cannot be solved at its root. Furthermore, existing heat exchangers and pressure regulating valves are mostly controlled independently, lacking a coordinated linkage mechanism, making it difficult to achieve optimal synergistic regulation under various operating conditions.

[0003] Therefore, it is necessary to design a condensate recovery and treatment unit with temperature and pressure regulation to solve the problems existing in the current technology. Summary of the Invention

[0004] In view of this, the present invention proposes a condensate recovery and treatment unit with temperature and pressure regulation, which aims to solve the problems of insufficient net positive suction head and lack of intelligent regulation mechanism caused by the current limited equipment layout.

[0005] This invention proposes a condensate recovery and treatment unit with temperature and pressure regulation, comprising:

[0006] A condensate tank is provided with a collection chamber and a temperature and pressure control chamber, which are connected by a partition with through holes. The collection chamber is provided with a condensate inlet, a safety valve, a pressure transmitter, a level gauge, and a level lifting device, which is used to lift the condensate to the temperature and pressure control chamber. A water-to-water heat exchanger is provided inside the temperature and pressure control chamber.

[0007] The water-to-water heat exchanger is connected to the circulating water inlet and the circulating water outlet, and the circulating water outlet is equipped with a temperature control valve; the water-to-water heat exchanger is equipped with a flow guiding and pressurizing device, which is connected to the inlet of at least two water pumps, and the outlet of each water pump is sequentially connected to a check valve, a pressure regulating valve and a condensate outlet.

[0008] Several pressure sensors and temperature sensors are installed between the water pump and the condensate tank.

[0009] The PLC control cabinet is used to limit the operating pressure of the water pump based on the real-time pressure difference between the temperature and pressure control chamber and the inlet and outlet of the water pump; dynamically adjust the start-stop strategy and operating time window of the standby water pump based on the changes in liquid level, temperature and pressure over a preset period and in combination with load data; and couple and analyze the feedback signals from the temperature transmitter and pressure transmitter to adjust the opening of the temperature control valve and pressure regulating valve in real time.

[0010] Furthermore, the liquid level raising device includes a flow guide shroud and a flow guide pipe connected to the through hole of the collection chamber. The inlet of the flow guide pipe is located below the liquid surface of the collection chamber, which is used to maintain a stable liquid flow of condensate in the temperature and pressure control chamber.

[0011] Furthermore, a high-level filter is provided on the through-hole channel between the temperature and pressure control chamber and the collection chamber. The high-level filter is equipped with a flange cover and a drain valve. The drain valve is connected to the drain collection port. The high-level filter is used to filter impurities in the condensate.

[0012] Furthermore, the water-to-water heat exchanger is equipped with a butterfly valve at the circulating water inlet and a temperature control valve at the circulating water outlet, and the temperature control valve is connected to the PLC control cabinet via a signal line.

[0013] Furthermore, the top of the condensate tank is equipped with an exhaust pipe, which is connected to a vent valve and an automatic exhaust valve, and the exhaust gas is released through the sewage collection port.

[0014] Furthermore, when the PLC control cabinet limits the operating pressure of the water pump based on the real-time pressure difference between the temperature and pressure regulating chamber and the inlet and outlet of the water pump, it includes:

[0015] Based on the pressure in the temperature and pressure control chamber, the pump inlet pressure, and the pump outlet pressure, the pump pressure rise range is obtained. The pump pressure rise range is compared with the differential pressure threshold, and the comparison result is used to determine whether it is in a safe operating range. When the pump pressure rise range is greater than the differential pressure threshold, it is determined that the differential pressure exceeds the upper limit, and the PLC control cabinet sends an adjustment signal to the pressure regulating valve to limit the pump operating pressure.

[0016] Furthermore, when the PLC control cabinet limits the operating pressure of the water pump based on the real-time pressure difference between the temperature and pressure regulating chamber and the inlet and outlet of the water pump, it also includes:

[0017] The PLC control cabinet calculates the short-term pressure difference trend based on the recent time-period pressure difference sequence and the water pump operating status using a prediction algorithm. When the prediction result indicates that the water pump outlet pressure continues to rise and approaches the limit, the PLC control cabinet adjusts the opening of the pressure regulating valve.

[0018] Furthermore, when the PLC control cabinet dynamically adjusts the start-stop strategy and pump operating time window of the standby water pump based on the changes in liquid level, temperature, and pressure over a preset period and in conjunction with load data, it includes:

[0019] The continuous monitoring values ​​of liquid level, temperature and pressure within a preset time period are processed by a sliding window to calculate the first difference and trend slope of the variables.

[0020] When the average slope of a continuous downward or upward trend exceeds the slope threshold, and the water pump is in a switchable operating condition, the standby water pump is pre-started, and the switching is completed before the water pump load exceeds the limit.

[0021] Furthermore, when the PLC control cabinet dynamically adjusts the start-stop strategy and pump operating time window of the standby water pump based on the changes in liquid level, temperature, and pressure over a preset period and in conjunction with load data, it also includes:

[0022] The real-time operating load is calculated based on the current output power, outlet pressure, and flow rate of the water pump.

[0023] The real-time operating load is compared with the high-efficiency range of the pump characteristic curve. If it deviates from the curve or the load is predicted to exceed the limit in the next period, the PLC control cabinet adjusts the operating window of the water pump and switches to the standby water pump.

[0024] Meanwhile, a weighted priority queue is constructed based on the cumulative running time and efficiency factor of each pump, and the pumps are selected for operation according to the rotation priority.

[0025] Furthermore, the PLC control cabinet's coupling analysis of the feedback signals from the temperature and pressure transmitters, and its real-time adjustment of the opening of the temperature control valve and pressure regulating valve, includes:

[0026] A two-dimensional temperature and pressure state diagram is constructed based on the real-time data collected by the temperature transmitter and pressure transmitter.

[0027] When the temperature is higher than the upper temperature threshold and the pressure before the pump is lower than the lower pressure threshold, the PLC control cabinet simultaneously increases the opening of the temperature control valve and decreases the opening of the pressure regulating valve.

[0028] When the temperature is higher than the upper temperature threshold and the pressure before the pump is higher than the upper pressure threshold, the PLC control cabinet increases the opening of the temperature control valve and expands the opening of the pressure regulating valve.

[0029] When the temperature is below the lower threshold temperature and the pressure before the pump is below the lower threshold pressure, the PLC control cabinet reduces the opening of the temperature control valve and the pressure regulating valve.

[0030] When the temperature is below the lower temperature threshold and the pressure before the pump is above the upper pressure threshold, the PLC control cabinet simultaneously reduces the opening of the temperature control valve and expands the opening of the pressure regulating valve.

[0031] The PLC control cabinet also adjusts the response speed based on the rate of temperature change and the rate of pressure change.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows: By constructing a condensate tank with a separate chamber structure for collecting and temperature and pressure regulating, and combining it with a liquid level lifting device, the condensate is automatically transferred from a low level to the heat exchange and pressure regulating area, avoiding the problem of insufficient gas chamber margin caused by equipment layout limitations; a water-to-water heat exchanger and a built-in flow guiding and pressurizing device are arranged in the temperature and pressure regulating chamber, and in conjunction with the temperature control valve on the cooling water circuit and the pressure regulating valve in the outlet water path, the dynamic regulation of condensate temperature and pump inlet pressure is achieved through PLC control cabinet coordination; the PLC control cabinet integrates multi-dimensional signals such as liquid level, temperature, pressure and pump load, and has the ability to schedule pump groups based on changing trends and the ability to couple temperature and pressure, and can adjust the start-stop strategy and operating window of the main pump and standby pump in real time under various operating conditions, and accurately regulate the cooling intensity and outlet back pressure, so that the pump inlet is always maintained in the optimal anti-cavitation range of "slight subcooling + slight positive pressure". Compared with traditional methods, this application solves the cavitation problem caused by space constraints, improves heat exchange efficiency, control accuracy and intelligence level, and achieves high efficiency and stability of condensate recovery system. Attached Figure Description

[0033] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0034] Figure 1 A schematic diagram of the upper part of a condensate recovery and treatment unit with temperature and pressure regulation provided in an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of the lower half of the condensate recovery and treatment unit with temperature and pressure regulation provided in an embodiment of the present invention.

[0036] The components include: 1. Condensate outlet; 2. Gate valve; 3. Pressure regulating valve; 5. Check valve; 9. Pressure gauge assembly; 10. Water pump PA; 11. Water pump PB; 17. Drain valve; 19. Vent valve; 20. Flow guiding and pressurizing device; 21. Drainage collection port; 23. Water-to-water heat exchanger; 24. Butterfly valve; 25. Circulating water inlet; 26. Circulating water outlet; 27. Temperature control valve; 28. High-level filter; 29. ​​Temperature and pressure control chamber; 30. Temperature transmitter; 31. Local thermometer; 32. Safety valve; 33. Liquid level lifting device; 34. Condensate inlet; 36. Pressure transmitter assembly; 37. Collection chamber; 39. Liquid level gauge; 41. PLC control cabinet; 42. Condensate tank; 44. Automatic vent valve. Detailed Implementation

[0037] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, embodiments and features in the embodiments of the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0038] In traditional condensate recovery and treatment systems, insufficient net positive suction head (NPSH) at the pump inlet due to installation height limitations makes condensate prone to localized vaporization during transport, leading to cavitation. Fixed-logic pressure or level control methods cannot dynamically adjust the switching strategy between the main and standby pumps based on real-time operating conditions, resulting in frequent pump start-ups and shutdowns and current surges. The lack of a coupling mechanism between temperature control and pressure regulation prevents the synergistic effect of maintaining a slightly subcooled and slightly positive pressure state at the pump inlet, causing positive feedback between system pressure fluctuations and temperature changes, further exacerbating the risk of cavitation.

[0039] For example, in a closed-loop condensate recovery system in a petrochemical plant, the condensate tank is installed on the ground floor due to space constraints, and the static pressure at the pump inlet is lower than the saturated vapor pressure corresponding to the current water temperature. When a sudden increase in steam load causes the condensate temperature to rise to 95°C, the pressure inside the tank fails to rise synchronously due to the lag in heat exchanger regulation, and the pressure before the pump drops below 0.12 MPa. At this time, cavitation collapse occurs in the pump impeller area, accompanied by vibration amplitude exceeding 4.5 mm / s. Simultaneously, the control system switches to the standby pump based on a fixed time window. When the load fluctuation cycle is 8-12 minutes, the main pump is forcibly shut down before reaching full load. After the standby pump starts, the sudden change in flow causes the outlet pressure to fluctuate by ±0.25 MPa, and the pressure regulating valve response delay exceeds 30 seconds, leading to pipeline pressure imbalance.

[0040] If the above problems are not addressed, impeller corrosion caused by cavitation will shorten the pump's service life to less than 60% of its design life, and the current surges generated by frequent start-stop cycles will accelerate the deterioration of the motor winding insulation. Decoupling of pressure and temperature control will prevent the system from maintaining a stable state under varying operating conditions. When the steam load change rate exceeds 15% / min, the pressure fluctuation amplitude increases to 2.3 times the initial value, potentially triggering a safety valve malfunction and causing media leakage. Furthermore, conflicting actions between the pressure regulating valve and heat exchanger under uncoordinated control will exacerbate energy loss. Actual measurements show that ineffective heat dissipation losses increase by 21% during peak-shaving periods, and overall energy efficiency drops below 78%.

[0041] For this, please refer to Figure 1-2 As shown, this application proposes a condensate recovery and treatment unit with temperature and pressure regulation, comprising: a condensate tank 42, which is provided with a collection chamber 37 and a temperature and pressure regulation chamber 29, the collection chamber 37 and the temperature and pressure regulation chamber 29 being connected by a partition with through holes. The collection chamber 37 is provided with a condensate inlet 34, a safety valve 32, a pressure transmitter, a level gauge 39, and a level lifting device 33, which is used to lift the condensate to the temperature and pressure regulation chamber 29. A water-to-water heat exchanger 23 is provided in the temperature and pressure regulation chamber 29. The water-to-water heat exchanger 23 is connected to a circulating water inlet 25 and a circulating water outlet 26, and a temperature control valve 27 is installed in the circulating water outlet 26. A flow guiding and pressurizing device 20 is provided in the water-to-water heat exchanger 23, which is connected to the inlets of at least two water pumps, and the outlets of the water pumps are sequentially connected to a check valve 5, a pressure regulating valve 3, and a condensate outlet 1. Several pressure and temperature sensors are installed between the water pump and the condensate tank 42. The PLC control cabinet 41 is used to limit the operating pressure of the water pump based on the real-time pressure difference between the temperature and pressure regulating chamber 29 and the inlet and outlet of the water pump. It dynamically adjusts the start-stop strategy and operating time window of the standby water pump based on the changes in liquid level, temperature, and pressure over a preset period and in conjunction with load data. It also analyzes the coupling of feedback signals from the temperature transmitter 30 and the pressure transmitter to adjust the opening of the temperature control valve 27 and the pressure regulating valve 3 in real time.

[0042] The condensate tank 42 is a container used for collecting and regulating condensate. It can be implemented using a divided-chamber design: a collection chamber 37 receives condensate, and a temperature and pressure regulating chamber 29 regulates temperature and pressure. A baffle plate ensures communication between the two chambers. A liquid level riser 33 maintains stable liquid flow, solving the problem that traditional tanks cannot simultaneously handle collection and temperature and pressure regulation. The water-to-water heat exchanger 23 is a device that uses cooling water and condensate for heat exchange. It can be implemented using a shell-and-tube structure. The circulating water inlet 25 and outlet connect to an external circulation system. A flow-guiding and pressurizing device 20 enhances heat exchange efficiency and balances water flow, solving the problem that traditional heat exchangers cannot coordinate temperature and pressure regulation. The flow-guiding and pressurizing device 20 is a component that guides water flow and increases pressure. It can be implemented using multi-stage guide vanes or a spiral pressurizing structure. It connects to the water pump inlet to optimize water flow distribution, solving the problem of insufficient net positive suction head (NPSH) at the water pump inlet. Among them, PLC control cabinet 41 refers to the automation control unit, which can be implemented by an industrial-grade programmable logic controller. By collecting pressure, temperature and liquid level data in real time and analyzing trends, it dynamically adjusts the valve opening and water pump operation strategy, solving the defect that traditional fixed control logic cannot adapt to multi-variable linkage.

[0043] This application integrates a water-to-water heat exchanger 23 and a flow-guiding and pressurizing device 20 into a chambered condensate tank 42, and combines this with multi-variable coordinated control of temperature, pressure, and liquid level by a PLC control cabinet 41 to achieve dynamic balance of temperature and pressure during condensate recovery, eliminate the risk of cavitation, and optimize the pump operation strategy to improve system stability.

[0044] The working process and principle of this application are as follows: the condensate tank 42 is divided into a collection chamber 37 and a temperature and pressure regulating chamber 29, which are connected by a partition with through holes. The collection chamber 37 is equipped with a condensate inlet 34, a safety valve 32, a pressure transmitter, a level gauge 39, and a level lifting device 33. The level lifting device 33 lifts the condensate from the collection chamber 37 to the temperature and pressure regulating chamber 29. The temperature and pressure regulating chamber 29 is equipped with a water-to-water heat exchanger 23, which is connected to the circulating water inlet 25 and the outlet. A temperature control valve 27 is installed at the outlet. The flow guiding and pressurizing device 20 in the water-to-water heat exchanger 23 is connected to at least two water pump inlets. The water pump outlets are sequentially connected to a check valve 5, a pressure regulating valve 3, and a condensate outlet 1. A pressure sensor and a temperature sensor are installed between the water pumps and the condensate tank 42.

[0045] The PLC control cabinet 41 limits the operating pressure of the water pump based on the real-time pressure difference between the temperature and pressure regulating chamber 29 and the inlet and outlet of the water pump. By monitoring the changes in liquid level, temperature, and pressure within a preset time period and combining this with load data, it dynamically adjusts the start-up and shutdown strategy and operating time window of the standby water pump. It couples and analyzes the feedback signals from the temperature transmitter 30 and the pressure transmitter to adjust the opening of the temperature control valve 27 and the pressure regulating valve 3 in real time.

[0046] Understandably, the NPSH at the pump inlet is increased through a chamber design and a level-raising device 33. The water-to-water heat exchanger 23 and the flow-guiding and pressurizing device 20 achieve coordinated temperature and pressure regulation. A dynamic pump control strategy optimizes start-up and shutdown timings to avoid frequent switching. Temperature-pressure coupling control ensures the pump inlet maintains a slightly subcooled and slightly positive pressure state, suppressing cavitation. Multi-sensor arrangement and PLC control enable intelligent system operation.

[0047] As a preferred embodiment, the solution of this application is implemented as follows: The condensate tank 42 adopts a cylindrical structure and is made of stainless steel. The collecting chamber 37 is located at the bottom, and the temperature and pressure regulating chamber 29 is located at the top, separated by a partition with through holes. Multiple circular through holes are evenly distributed on the partition. A condensate inlet 34 is provided at the bottom of the collecting chamber 37, and a safety valve 32, a pressure transmitter, and a level gauge 39 are installed at the top. The level lifting device 33 consists of a submersible pump and a guide pipe, which draws condensate from the bottom of the collecting chamber 37 and transports it to the top of the temperature and pressure regulating chamber 29. A plate heat exchanger is installed in the temperature and pressure regulating chamber 29 as a water-to-water heat exchanger 23. One side of the heat exchanger is connected to the circulating water inlet 25 and the outlet, and an electric regulating valve is installed at the outlet as a temperature control regulating valve 27. A flow guiding and pressurizing device 20 is provided on the other side of the heat exchanger, which consists of multi-stage centrifugal impellers and is connected to the inlet of at least two vertical multi-stage centrifugal pumps. The pump outlet is sequentially connected to a check valve 5, an electric regulating valve serving as a pressure regulating valve 3, and finally to the condensate outlet 1. Multiple pressure and temperature sensors are arranged at the pump inlet and outlet, as well as within the temperature and pressure control chamber 29. These sensors are connected to the PLC control cabinet 41 via signal lines. The PLC control cabinet 41 adopts a modular structure, including analog input modules, digital input / output modules, a communication module, and a central processing unit. The PLC control cabinet 41 executes the following control logic: Based on the real-time pressure difference between the temperature and pressure control chamber 29 and the pump inlet and outlet, it calculates the pump pressure rise range and compares it with a preset threshold. When the pressure exceeds the safe operating range, it sends a regulating signal to the pressure regulating valve 3 to limit the pump's operating pressure. It processes the level, temperature, and pressure monitoring values ​​within a preset time period through a sliding window and calculates the trend. When the trend exceeds the threshold and the pump is switchable, it triggers the pre-start of the standby pump. Based on the pump's current output power, pressure, and flow rate, it calculates the real-time load, compares it with the pump characteristic curve, and dynamically adjusts the operating time window. A two-dimensional temperature and pressure state diagram is constructed. Based on the combined state of temperature and pressure, the opening of the temperature control valve 27 and the pressure regulating valve 3 are coordinated and adjusted to ensure that the water pump inlet maintains a slightly subcooled and slightly positive pressure state.

[0048] Through the above-described scheme, this application achieves intelligent temperature and pressure control of the condensate recovery and treatment system. The chamber design and the level riser 33 improve the cavitation margin at the pump inlet, effectively suppressing cavitation. The dynamic pump control strategy avoids frequent pump start-ups and shutdowns, reducing current surges. The temperature and pressure coupling control mechanism ensures stable system operation under varying conditions, reducing pressure fluctuations. The synergistically optimized heat exchanger and pressure regulating valve 3 control reduces energy loss and improves the overall system energy efficiency. This scheme solves the problems of cavitation, instability, and low energy efficiency in traditional condensate recovery systems, improving the system's reliability and economy.

[0049] In some of the above-mentioned solutions of this application, the liquid level lifting device 33 is used to lift condensate from the collection chamber 37 to the temperature and pressure control chamber 29. However, during the lifting process, when the condensate flows through the through hole, turbulence may occur due to liquid surface fluctuations or changes in flow velocity, resulting in unstable liquid flow, which in turn affects the pressure balance in the temperature and pressure control chamber 29 and increases the risk of cavitation.

[0050] This application further proposes a liquid level raising device 33 including a guide shroud and a guide pipe connected to the through hole of the collection chamber 37. The inlet of the guide pipe is located below the liquid surface of the collection chamber 37, which is used to maintain a stable liquid flow of condensate in the temperature and pressure regulating chamber 29.

[0051] The flow guide shroud is fixed above the through-hole of the collection chamber 37, and the flow guide pipe is connected to the flow guide shroud and extends below the liquid surface in the collection chamber 37. The cross-sectional shape of the flow guide shroud can be conical or cylindrical, and its diameter is larger than the diameter of the through-hole, used to guide condensate to flow evenly into the through-hole. The inlet end of the flow guide pipe is located at least 100 mm below the liquid surface to prevent air intake caused by liquid surface fluctuations. The connection between the flow guide pipe and the flow guide shroud is sealed and fixed by flange or welding to prevent leakage. The diameter of the flow guide pipe is designed according to the condensate flow rate, for example, DN50 to DN200, and the flow velocity is controlled within the range of 0.5-1.5 m / s. The combined structure of the flow guide shroud and the flow guide pipe can suppress the formation of eddies in the liquid flow at the through-hole and reduce sudden drops in local pressure.

[0052] Specifically, when condensate in collection chamber 37 enters temperature and pressure control chamber 29 through the through-hole, the guide shroud covers the through-hole area, constraining the liquid flow direction and preventing disordered flow. The inlet of the guide pipe is located below the liquid surface, ensuring that condensate always enters the guide pipe in a submerged state, forming a continuous liquid column. When the liquid level drops, the inlet depth of the guide pipe can still maintain the continuity of liquid flow, preventing gas from mixing in. The combined structure of the guide pipe and the guide shroud keeps the liquid flow in a laminar state during the lifting process, reducing pressure fluctuations. The stable liquid flow reduces the pressure fluctuation amplitude at the water pump inlet, and in conjunction with the dynamic limitation of the water pump operating pressure by the PLC control cabinet 41, further suppresses cavitation. By maintaining the stability of the liquid flow, the water-to-water heat exchanger 23 in temperature and pressure control chamber 29 can perform heat exchange more efficiently, avoiding temperature control lag caused by sudden changes in flow rate.

[0053] As a preferred embodiment, the solution of this application is specifically implemented as follows:

[0054] The liquid level raising device 33 includes a flow guide shroud and a flow guide pipe connected to the through hole of the collecting chamber 37. The flow guide shroud is funnel-shaped, with the upper port diameter larger than the lower port diameter, and is installed around the through hole of the collecting chamber 37. The flow guide pipe is a straight pipe structure, with one end connected to the lower end of the flow guide shroud and the other end extending below the liquid surface in the collecting chamber 37. The inlet of the flow guide pipe is located approximately 50-100 mm below the liquid surface in the collecting chamber 37.

[0055] In practical applications, after condensate enters the collection chamber 37 through the condensate inlet 34, some condensate will enter the temperature and pressure control chamber 29 through the guide pipe during the liquid level rise. The funnel-shaped structure of the guide shroud can guide the condensate to flow smoothly into the guide pipe, reducing turbulence. The inlet of the guide pipe is located below the liquid surface, which can prevent gas from entering and ensure that the condensate enters the temperature and pressure control chamber 29 in a stable liquid flow manner.

[0056] Through the above technical solution, this application can achieve a smooth transition of condensate from the collection chamber 37 to the temperature and pressure control chamber 29. The design of the flow guide and the flow pipe can reduce the generation of air bubbles in the condensate during the flow process and avoid cavitation. At the same time, by controlling the inlet position of the flow pipe, it can be ensured that only liquid condensate enters the temperature and pressure control chamber 29, improving the stability and reliability of the system. This design can also alleviate pressure fluctuations in the condensate tank 42 to a certain extent, which is conducive to maintaining the pressure balance of the entire system.

[0057] In some of the solutions described above in this application, during the process of condensate flowing from the collection chamber 37 to the temperature and pressure control chamber 29, impurities may enter the through-hole channel with the water flow and cause blockage, or enter subsequent equipment and cause wear, affecting the stability of the system.

[0058] This application further proposes to install a high-level filter 28 on the through-hole channel between the temperature and pressure control chamber 29 and the collection chamber 37. The high-level filter 28 is equipped with a flange cover and a drain valve 17. The drain valve 17 is connected to the drain collection port 21. The high-level filter 28 is used to filter impurities in the condensate.

[0059] The high-level filter 28 is fixed to the pipe section of the through-hole channel using a flange connection. The flange cover is fastened to the flange plate with bolts, forming a detachable sealing structure. The drain valve 17 is installed at the bottom of the filter and connects to the drain collection port 21 via a pipe. The drain collection port 21 extends to an external collection container or drainage network. The filter element of the high-level filter 28 uses a multi-layer stainless steel mesh structure with a mesh size of 0.5-1.0 mm, which can intercept impurities such as rust and particulate matter.

[0060] Specifically, when condensate enters the temperature and pressure control chamber 29 from the collection chamber 37 through the through-hole channel, the water first passes through the high-level filter 28. After the filter element intercepts impurities, the clean water flows into the subsequent water-to-water heat exchanger 23 and the water pump system. During operation, operators can periodically open the flange cover to clean or replace the filter element, and simultaneously discharge impurities deposited at the bottom of the filter through the drain valve 17. The draining action can be manually operated or linked with the PLC control cabinet 41 to achieve timed discharge. This structure not only prevents impurities from clogging the through-hole channel, but also prevents particulate matter from entering the water pump impeller, causing aggravated cavitation or mechanical damage, thereby extending the service life of the equipment. The removable design of the flange cover further reduces maintenance difficulty and ensures continuous effective filtration.

[0061] As a preferred embodiment, the solution of this application is specifically implemented as follows:

[0062] A high-level filter 28 is installed in the through-hole channel between the temperature and pressure control chamber 29 and the collection chamber 37. The high-level filter 28 includes a flange cover and a drain valve 17. The drain valve 17 is connected to the drain collection port 21. The high-level filter 28 is used to filter impurities in the condensate.

[0063] Specifically, the high-level filter 28 is made of stainless steel and has multiple layers of filter screens inside. The screens, from the outside in, are 100 mesh, 200 mesh, and 400 mesh, respectively, to achieve graded filtration of impurities of different particle sizes. The flange cover is bolted to the top of the high-level filter 28 for easy periodic cleaning and replacement of the filter screens. The drain valve 17 is an electric ball valve connected to the PLC control cabinet 41. The PLC control cabinet 41 automatically controls the opening time and frequency of the drain valve 17 based on the pressure difference changes of the high-level filter 28. The drain collection port 21 is connected to the wastewater treatment system to ensure that impurities are properly treated.

[0064] Through the above technical solutions, this application achieves effective filtration of impurities in condensate, preventing impurities from entering the temperature and pressure control chamber 29 and avoiding blockage or wear on the water-to-water heat exchanger 23 and the water pump. The high-level filter 28 is positioned to utilize gravity, improving filtration efficiency. The flange cover design facilitates regular inspection and cleaning by maintenance personnel, extending the filter's service life. The automatic sewage discharge function reduces manual operation and improves the system's automation level. The sewage collection port 21 ensures unified collection and treatment of impurities, preventing secondary pollution.

[0065] In some of the solutions described above in this application, the circulating water inlet 25 and outlet of the water-to-water heat exchanger 23 are controlled by a single valve, which cannot achieve coordinated operation of coarse adjustment of inlet flow and fine adjustment of outlet temperature. This results in uneven water flow distribution inside the heat exchanger, delayed temperature regulation, and consequently affects the stability of the condensate cooling process.

[0066] This application further proposes that the circulating water inlet 25 of the water-to-water heat exchanger 23 is equipped with a butterfly valve 24, and the circulating water outlet 26 is equipped with a temperature control valve 27. The temperature control valve 27 is connected to the PLC control cabinet 41 via a signal line.

[0067] The butterfly valve 24 is installed on the circulating water inlet pipe 25 via a flange connection. Its valve plate rotation angle is linearly related to the inlet diameter, and its opening is adjusted manually or electrically. The temperature control valve 27 is a proportional-integral control valve; its valve core stroke forms a closed-loop control with the outlet water temperature, and a temperature sensing unit is integrated inside the valve body. The signal line uses shielded twisted-pair cable to connect the 4-20mA analog input port of the temperature control valve 27 to the AI ​​module channel of the PLC control cabinet 41, forming a real-time signal transmission link.

[0068] Specifically, when circulating water enters the water-to-water heat exchanger 23 through the inlet butterfly valve 24, the opening range of the butterfly valve 24 is 0° to 90°, corresponding to 0% to 100% of the flow diameter cross-sectional area. The operator fixes the opening of the butterfly valve 24 within the 40%-60% range according to the initial system conditions, forming a basic flow supply. The temperature control valve 27 at the outlet receives a pulse width modulation signal sent by the PLC control cabinet 41 and adjusts the valve core position at an angular velocity of 0.5°-2° per second, maintaining the circulating water outlet temperature 26 within the set range of 50℃±2℃. When the condensate temperature sensor detects that the water temperature after heat exchange exceeds the threshold, the PLC control cabinet 41 calculates the temperature deviation value within 200ms and generates a valve opening correction command through a PID algorithm. This command is converted into a 4-20mA current signal by the DA module to drive the valve body stepper motor, causing the valve core to move axially and changing the flow channel cross-sectional area. Dynamic adjustment of circulating water flow rate creates a stable temperature gradient between the tube side and shell side of the heat exchanger, effectively avoiding condensate pressure fluctuations caused by sudden temperature changes.

[0069] As a preferred embodiment, the solution of this application is implemented as follows: A butterfly valve 24 is installed at the circulating water inlet 25 of the water-to-water heat exchanger 23, and a temperature control valve 27 is installed at the circulating water outlet 26. The temperature control valve 27 is connected to the PLC control cabinet 41 via a signal line. Specifically, the butterfly valve 24 at the circulating water inlet 25 is used to control the inflow of circulating water and its opening can be manually adjusted. The temperature control valve 27 at the circulating water outlet 26 is controlled in real time by the PLC control cabinet 41 via a signal line. The PLC control cabinet 41 dynamically adjusts the opening of the temperature control valve 27 based on the temperature signal fed back by the temperature sensor, thereby precisely controlling the flow rate and heat exchange effect of the circulating water. For example, when the condensate temperature is detected to be too high, the PLC control cabinet 41 will send a signal to increase the opening of the temperature control valve 27, increasing the circulating cooling water flow rate. Conversely, it will decrease the opening. This closed-loop control method can keep the condensate temperature within the set range at all times.

[0070] Through the above technical solution, this application achieves precise control of condensate temperature. Therefore, the condensate temperature can be maintained within an ideal range, avoiding excessively high temperatures that affect system efficiency or excessively low temperatures that lead to energy waste. Furthermore, the linkage between the temperature control valve 27 and the PLC control cabinet 41 enables the system to respond quickly to temperature changes, improving the sensitivity and accuracy of temperature regulation. This intelligent temperature control method, compared to traditional manual adjustment, improves the system's automation level and operational stability.

[0071] In some of the schemes described above in this application, gas may accumulate at the top of the condensate tank 42, causing pressure fluctuations and unstable liquid levels inside the tank, affecting the control of the net positive suction head (NPSH) at the water pump inlet, and thus exacerbating the cavitation phenomenon.

[0072] This application further proposes that the top of the condensate tank 42 is provided with an exhaust pipe, which is connected to the vent valve 19 and the automatic exhaust valve 44, and the exhaust gas is released through the sewage collection port 21.

[0073] The vent pipe is vertically installed at the top center of the condensate tank 42. The vent valve 19 is a manual ball valve located in the middle section of the vent pipe. The automatic vent valve 44 is a float-type structure installed at the end of the vent pipe, which automatically opens when the gas pressure inside the tank exceeds a set threshold. The sewage collection port 21 is a stainless steel pipe that is connected to the outlets of the vent valve 19 and the automatic vent valve 44 via flanges, extending to the external sewage system.

[0074] Specifically, during the operation of the condensate tank 42, steam and non-condensable gases in the collection chamber 37 and the temperature and pressure control chamber 29 escape upwards through the through holes and accumulate at the top of the tank. The exhaust pipe is directly connected to the gas phase space inside the tank through the top opening. The automatic exhaust valve 44 adjusts the exhaust volume in real time according to changes in the tank pressure. For example, when the pressure exceeds 0.15 MPa, the float is pushed by the air pressure to open the exhaust channel. The vent valve 19 serves as a redundant control and is manually opened for forced exhaust when the automatic exhaust valve 44 fails. The discharged gas and the impurity liquid discharged from the high-level filter 28 and the drain valve 17 flow together into the drain collection port 21, avoiding secondary pollution caused by separate gas discharge. This structure achieves unified management of the gas and liquid two-phase discharge paths through physical separation, ensuring that the tank pressure is stable within the range of 0.05-0.12 MPa, maintaining a slightly positive pressure at the water pump inlet, and reducing the probability of cavitation.

[0075] As a preferred embodiment, the solution of this application is specifically implemented as follows:

[0076] A vent pipe is installed at the top of the condensate tank 42. The vent pipe connects to the vent valve 19 and the automatic vent valve 44. The discharged gas is released through the drain port 21. Specifically, the vent pipe can be made of stainless steel, with an inner diameter of 50mm and a wall thickness of 3mm. The vent valve 19 can be a manual ball valve with a nominal diameter of DN40. The automatic vent valve 44 can be a float-type automatic vent valve with a working pressure range of 0-1.6MPa. The drain port 21 can be located at the bottom of the unit, using a flange connection, with a nominal diameter of DN80. The vent pipe, vent valve 19, automatic vent valve 44, and drain port 21 are connected by flanges or threads.

[0077] Through the above technical solution, this application achieves effective discharge of gas from the condensate tank 42. This avoids pressure fluctuations caused by gas accumulation in the tank, ensuring the stability of the pressure inside the condensate tank 42. Furthermore, the automatic exhaust valve 44 allows for continuous discharge of accumulated gas without manual intervention, improving the system's automation level. Simultaneously, the discharged gas is directed to the wastewater collection port 21 for centralized treatment, avoiding potential environmental pollution from direct gas discharge and enhancing the system's environmental performance.

[0078] Specifically, since there are multiple pressure gauge assemblies, multiple gate valves, multiple pressure regulating valves, multiple drain valves, and multiple check valves in the attached diagram, and since their functions are consistent, structures with the same function are numbered the same.

[0079] Specifically, in a preferred embodiment of this application, the collecting chamber 37 is provided with a steam condensate inlet 34, and is also equipped with a safety valve 32, a pressure gauge assembly 9, and a pressure transmitter assembly 36. The pressure transmitter signal is transmitted to the PLC control cabinet 41. A level gauge 39 is installed on the side, and level gauge gate valves are installed at both ends of the level gauge 39. The level gauge 39 signal is transmitted to the PLC control cabinet 41. A local thermometer 31 and a temperature transmitter 30 are installed in the liquid phase part of the temperature and pressure regulating chamber 29. The temperature transmitter 30 signal is transmitted to the PLC control cabinet 41. Multiple through holes are drilled above the partition between the collecting chamber 37 and the temperature and pressure regulating chamber 29. A water collection steel pipe is welded to each through hole. Each water collection steel pipe is connected to a condensate level lifting device 33. The level lifting device 33 is provided with multiple guide hoods and guide pipes. The inlet of the guide pipe is located below the condensate liquid surface in the collecting chamber 37.A high-level filter 28 is installed on the steel pipe channel through the partition hole between the temperature and pressure control chamber 29 and the collection chamber 37. A flange and flange cover are welded to the outside of the temperature and pressure control chamber 29 at the other end of the high-level filter 28. The flange cover pipe connects to the drain valve 17 of the high-level filter 28, and then to the drain collection port 21. A water-to-water heat exchanger 23 with baffles is designed and installed inside the temperature and pressure control chamber 29. A built-in flow guiding and pressurizing device 20 is installed at the outlet of the water-to-water heat exchanger 23. A temperature control regulating valve 27 is installed at the circulating water outlet 26 of the water-to-water heat exchanger 23. The signal line of the temperature control valve is connected to the PLC control cabinet 41. A butterfly valve 24 is installed at the circulating water inlet 25 of the water-to-water heat exchanger 23. An air vent pipe is installed at the top of the condensate tank 42, extending downwards and equipped with a vent valve 19 connected to the drain port 21. A drain valve 17 is installed at the bottom of the temperature and pressure control chamber 29 and connected to the drain port 21. A drain valve 17 is installed at the bottom of the collection chamber 37 and connected to the drain port 21. The temperature and pressure control chamber 29 is equipped with a built-in flow guiding and pressurizing device 20 using multiple partitions and a... Composed of a cover plate, the built-in flow guiding and pressurizing device 20 has a bypass connection to a regulating valve at its outlet. The electrical control circuit of the regulating valve is connected to the PLC control cabinet 41. The front end of the regulating valve is connected to a check valve 5, and then to the gate valve 2 at the condensate outlet 1. The outlet of the built-in flow guiding and pressurizing device 20 leads to water pumps P-A10 and P-B11. Inlet gate valves 2 and 2 are installed in front of the inlets of the two water pumps, respectively. The outlet of water pump P-A10 is connected to check valve 5, gate valve 2, and pressure regulating valve 3, and then leads to gate valve 2 and condensate outlet 1. Water pump P-A10 A pressure gauge assembly 9 is installed on the outlet pipe. The motor of water pump P-A10 is connected to PLC control cabinet 41. The outlet of water pump P-B11 is connected to check valve 5, gate valve 2, and pressure regulating valve 3, and then to gate valve 2 and condensate outlet 1. A pressure gauge assembly 9 is installed on the outlet pipe of water pump P-B11. The motor of water pump P-B11 is connected to PLC control cabinet 41. An exhaust pipe is installed at the top of the collection chamber 37. The exhaust pipe extends downwards and is equipped with gate valve 2 and automatic exhaust valve 44. Automatic exhaust valve 44 is connected to sewage collection port 21.

[0080] In some of the solutions described above in this application, the PLC control cabinet 41 achieves operation control by monitoring the temperature and pressure regulating chamber 29 and the inlet and outlet pressures of the water pump, but the dynamic pressure difference limiting mechanism is not clearly defined, which may cause the water pump pressure rise range to exceed the equipment pressure limit and cause the system overpressure risk.

[0081] This application further proposes a control method that calculates the pump pressure rise range based on the pressure of the temperature and pressure regulating chamber 29, the pump inlet pressure and the pump outlet pressure, compares the pressure rise range with a preset pressure difference threshold, determines the safe operating range based on the comparison result, and limits the pump operating pressure through the pressure regulating valve 3 when the pressure rise range exceeds the threshold.

[0082] The pressure rise range is calculated based on the pressure difference between the temperature and pressure control chamber 29 and the pump outlet pressure. The pressure difference threshold is set according to the pump's rated head and the pipeline's pressure-bearing capacity. The opening adjustment signal of the pressure regulating valve 3 is generated using a PID algorithm, with the adjustment response time controlled in milliseconds. The pressure sensors are arranged redundantly, including at least two independent acquisition modules. The data is input to the PLC after mean filtering.

[0083] Specifically, the pressure sensor collects real-time pressure data from the temperature and pressure control chamber 29, the pump inlet, and the outlet. The PLC obtains the pressure value via the data bus and calculates the pump pressure rise range. The differential pressure threshold is set to 85%-95% of the pump's rated differential pressure. When the real-time pressure rise range exceeds the upper limit of the threshold, the PLC outputs a pulse width modulation signal to the pressure regulating valve 3, driving the valve core of the pressure regulating valve 3 to linearly displace, reducing the flow cross-sectional area and lowering the outlet pressure. If the pressure rise range continues to exceed the threshold for more than 5 seconds, the PLC triggers an alarm and executes pump frequency reduction operation. The opening adjustment of the pressure regulating valve 3 is directly proportional to the differential pressure deviation, and the proportional coefficient is dynamically adjusted according to the pump characteristic curve. During the pressure limiting process, the PLC synchronously monitors the pump current fluctuation. If the current abnormally increases by more than 10% of the rated value, the control circuit of the pressure regulating valve 3 is immediately cut off and the standby pump is started.

[0084] As a preferred embodiment, the solution of this application is specifically implemented as follows:

[0085] The PLC control cabinet 41 limits the water pump's operating pressure based on the real-time pressure difference between the temperature and pressure regulating chamber 29 and the water pump's inlet and outlet. Specifically, it first acquires real-time data on the pressure in the temperature and pressure regulating chamber 29, the water pump inlet pressure, and the water pump outlet pressure. Then, it calculates the water pump pressure rise range, i.e., the difference between the water pump outlet pressure and the inlet pressure. Further, it compares the calculated water pump pressure rise range with a preset pressure difference threshold. This determines whether the water pump is within its safe operating range.

[0086] For example, a differential pressure threshold can be set to 0.5 MPa. When the water pump pressure rise exceeds 0.5 MPa, the differential pressure is determined to have exceeded the upper limit. At this time, the PLC control cabinet 41 sends an adjustment signal to the pressure regulating valve 3 to limit the water pump operating pressure. Specifically, the adjustment method can be to gradually reduce the opening of the pressure regulating valve 3 until the water pump pressure rise range drops to within the safe range.

[0087] As a preferred implementation, the PLC control cabinet 41 can also calculate the short-term pressure difference trend based on the recent pressure difference sequence and the water pump operating status using a predictive algorithm. For example, linear regression or exponential smoothing methods can be used to analyze the trend of the pressure difference data over the past 30 minutes. When the prediction results indicate that the water pump outlet pressure continues to rise and approaches the limit, the PLC control cabinet 41 can adjust the opening of the pressure regulating valve 3 in advance to achieve preventive control.

[0088] Through the above technical solution, this application can achieve dynamic limitation and precise control of the operating pressure of the water pump. This effectively prevents problems such as cavitation and vibration caused by excessive pressure differentials, extending the pump's service life. Simultaneously, through predictive control, pressure fluctuations can be addressed in advance, ensuring the stability and safety of system operation. Furthermore, this solution can reduce energy consumption, minimize unnecessary pressure loss, and improve the overall operating efficiency of the condensate recovery and treatment system.

[0089] In some of the solutions described above in this application, when limiting the operating pressure of the water pump based on the real-time pressure difference between the temperature and pressure control chamber 29 and the inlet and outlet of the water pump, the adjustment of the pressure regulating valve 3 is determined solely by the current pressure difference threshold. This results in a lag in the adjustment. When the outlet pressure of the water pump rises rapidly to near the limit in a short period of time, the pressure regulating valve 3 cannot respond in time, which may lead to the risk of the system pressure exceeding the limit.

[0090] This application further proposes that the PLC control cabinet 41 calculates the short-term pressure difference trend based on the recent time-period pressure difference sequence and the water pump operating status through a prediction algorithm. When the prediction result shows that the water pump outlet pressure continues to rise and approaches the limit, the PLC control cabinet 41 adjusts the opening of the pressure regulating valve 3.

[0091] The differential pressure sequence is generated by collecting historical data on the pressure in the temperature and pressure control chamber 29, the inlet pressure of the water pump, and the outlet pressure within a preset time window. The prediction algorithm uses the moving average method or the exponential smoothing method to fit the trend of the differential pressure sequence. The opening adjustment range of the pressure regulating valve 3 is dynamically calculated based on the slope of the predicted trend and the remaining safety margin. The rate of change of the opening is positively correlated with the rate of pressure rise.

[0092] Specifically, the PLC control cabinet 41 collects water pump inlet pressure, outlet pressure, and temperature and pressure control chamber 29 pressure data at fixed intervals, calculates the current pressure difference value, and stores it in the historical sequence. The prediction algorithm weights multiple consecutive pressure difference values ​​in the sequence to generate a pressure change prediction curve for the next three sampling periods. When the prediction curve shows that the outlet pressure will exceed 90% of the safety limit in the next period, the PLC control cabinet 41 calculates the amount of adjustment required to increase the opening of the pressure regulating valve 3 in advance based on the pressure rise rate and the current opening state of the pressure regulating valve 3. The pressure regulating valve 3 begins to increase its opening before the actual pressure reaches the threshold, slowing down the rate of increase in outlet pressure and avoiding triggering a protective shutdown. The faster the pressure rise rate, the larger the adjustment range of the pressure regulating valve 3, and the advance amount of the adjustment action increases with the increase of prediction confidence.

[0093] As a preferred embodiment, the solution of this application is specifically implemented as follows:

[0094] Based on the recent differential pressure sequence and the water pump's operating status, the PLC control cabinet 41 calculates the short-term differential pressure trend using a predictive algorithm. Specifically, the PLC control cabinet 41 first collects data sequences of the pressure in the temperature and pressure control chamber 29, the water pump inlet pressure, and the outlet pressure over the past 30 minutes, collecting data every 10 seconds. Then, using time series analysis methods, such as exponential smoothing or the ARIMA model, it performs short-term predictions on the differential pressure data, forecasting the differential pressure change trend over the next 5 minutes.

[0095] When the prediction indicates that the pump outlet pressure is continuously rising and approaching the limit, the PLC control cabinet 41 automatically adjusts the opening of the pressure regulating valve 3. For example, if the prediction shows that the pump outlet pressure will exceed the set safety threshold of 95% in 5 minutes, the PLC control cabinet 41 will send a signal to the pressure regulating valve 3 to gradually increase its opening. The adjustment of the pressure regulating valve 3 opening adopts a PID control algorithm, which dynamically adjusts the opening change rate according to the deviation between the current pressure and the target pressure, as well as the pressure change rate, to ensure a smooth transition to the new pressure state.

[0096] Through the above technical solution, this application achieves proactive control of the pump's operating pressure. By predicting and promptly adjusting short-term pressure differential trends, it effectively prevents sudden over-limits in the pump outlet pressure. This proactive prevention control strategy improves the system's operational stability and safety, reducing the risk of equipment damage caused by pressure fluctuations. Simultaneously, by adjusting the pressure regulating valve opening in advance, large-scale sudden adjustments are avoided, resulting in smoother system pressure changes, extending equipment lifespan, and reducing energy consumption.

[0097] Understandably, traditional systems employ fixed-logic pressure or level control methods, which cannot intelligently switch between the main and standby pumps based on real-time operating conditions. This leads to frequent pump start-ups and shutdowns, large start-up and shutdown current surges, and system instability. Furthermore, current technology cannot predict pump load changes based on dynamic trends in level, temperature, and pressure, making it difficult to adjust operating strategies in a timely manner and easily causing overload.

[0098] This application further proposes a scheme to dynamically adjust the start-up and shutdown strategy and pump operating time window of the standby water pump based on the changing trends of liquid level, temperature, and pressure over a preset time period, combined with load data. This includes: processing the continuous monitoring values ​​of liquid level, temperature, and pressure within a preset time period using a sliding window, and calculating the first difference and trend slope of the variables. When the average slope of a continuous decreasing or increasing trend exceeds a slope threshold, and the pump's operating status is switchable, the standby water pump is pre-started, completing the switchover before the pump load exceeds the limit.

[0099] The sliding window processing method uses a fixed-length window to capture monitoring data, with the window length set to 5-10 minutes and each sliding step being 1 minute. First-order difference calculation obtains the rate of change by the difference between data points at adjacent time points, and the trend slope is fitted using the least squares method to fit the trend of data change within the window. The slope threshold is dynamically adjusted based on 60%-80% of the pump's rated power; a valid trend is determined when the slope of three consecutive windows exceeds the threshold. Switching conditions include the standby pump being in standby mode, the current pump's cumulative operating time not reaching its maintenance cycle, and system load fluctuations within acceptable limits.

[0100] Specifically, the continuous monitoring data of liquid level, temperature, and pressure are processed through a sliding window, and the instantaneous change rate of each variable is calculated using first-order difference. For example, when the liquid level change rate exceeds ±2% per minute, the trend slope calculation is triggered. If the trend slope of any variable among liquid level, temperature, and pressure exceeds a preset threshold, and the current output power of the water pump reaches 75% of its rated power, it is determined that there is a risk of overload. At this time, the PLC control cabinet 41 starts the standby water pump in advance and completes the switch when the outlet pressure of the current water pump reaches 90% of the critical value. During the switch, the pressure regulating valve 3 gradually reduces the outlet pressure of the current water pump, while the pressure regulating valve 3 of the standby water pump increases the pressure according to a preset gradient to ensure that the system pressure fluctuation is controlled within ±5%. By comparing the real-time operating load with the high-efficiency range of the pump characteristic curve, when it is detected that the efficiency of the current water pump is lower than the lower limit of the high-efficiency range of the curve, the system immediately switches to the standby water pump and adds the current water pump to the maintenance queue.

[0101] As a preferred embodiment, the specific implementation of this application is as follows: The monitoring window for liquid level, temperature, and pressure is preset to five minutes in the PLC control cabinet 41. The continuously collected liquid level data is processed using a rolling average. A first-order difference sequence is obtained by calculating the difference in liquid level changes between two adjacent sampling points. A linear regression method is then used to fit the slope of the liquid level trend. When the absolute value of the slope of three consecutive liquid level monitoring windows exceeds 0.3 m / min and the water pump is not at full load, the standby water pump pre-start program is triggered. At this time, the control cabinet starts the standby water pump in advance and completes the switching action before the current water pump load reaches 85% of its rated value. The switching condition is further combined with the water pump outlet pressure fluctuation rate and current change rate for composite judgment. When the pressure fluctuation rate exceeds 5% or the current change rate exceeds 10%, a forced switching operation is immediately executed.

[0102] Through the above technical solution, this application can predict the potential overload risk of water pumps based on real-time operating data, and complete the seamless switching of standby water pumps before the load exceeds the limit, avoiding frequent pump start-ups and shutdowns or sudden pressure drops due to sudden load changes. By using sliding window and trend slope analysis, the direction of system state changes is accurately identified, and the water pump operating time window is dynamically adjusted in combination with composite switching conditions, effectively reducing the damage of current surges to electrical components and maintaining the continuous stability of pressure and flow in the condensate recovery system.

[0103] In some of the solutions mentioned above in this application, the dynamic adjustment of the standby water pump start-up and shutdown strategy is based solely on the trend adjustment of liquid level, temperature, and pressure, without taking into account the actual operating load of the water pump and the difference in pump efficiency. This results in inaccurate judgment of the switching timing, which may lead to switching delays or premature switching, causing system pressure fluctuations and increased equipment wear.

[0104] This application further proposes a method to calculate the real-time operating load based on the pump's current output power, outlet pressure, and flow rate. The real-time operating load is compared with the high-efficiency range of the pump characteristic curve. If the load deviates from the curve or is predicted to exceed limits in the next period, the pump's operating window is adjusted, and the system switches to standby pump operation. Simultaneously, a weighted priority queue is constructed based on the cumulative operating time and efficiency factor of each pump, and the operating pump is selected according to its rotation priority.

[0105] The real-time operating load is obtained by combining the power calculation formula with the outlet pressure and flow parameters, with the specific parameter acquisition cycle at the second level. The high-efficiency range of the pump characteristic curve is pre-stored in the database of PLC control cabinet 41, and the comparison process uses interpolation to match the current operating point. The construction of the weighted priority queue is realized through a linear weighted model, with the weight coefficients of cumulative running time and efficiency factor being 0.6 and 0.4, respectively, and the rotation priority is updated every 24 hours.

[0106] Specifically, the PLC control cabinet 41 collects real-time data on pump outlet pressure and flow rate using pressure sensors and flow meters, and calculates output power by combining this with motor current values ​​to form a quantitative indicator of operating load. This indicator is compared in real-time with the high-efficiency range of the pump characteristic curve. When the load value deviates from the median value of the high-efficiency range by more than 15% or the prediction model indicates that it may exceed the limit within the next 5 minutes, a standby pump start command is triggered. During this process, the weighted priority queue is dynamically sorted according to the historical operating time and efficiency decay data of each pump, prioritizing the pump with the shortest cumulative operating time and the highest efficiency factor. For example, when pump 1's cumulative operating time reaches 120 hours and its efficiency factor drops to 0.85, the system automatically switches pump 2 to the priority operation target, while simultaneously adding pump 1 to the maintenance queue. This mechanism ensures a smooth load transition while improving the overall efficiency of the multi-pump system by 12%-18% and extending the mean time between failures (MTBF) by 30%.

[0107] As a preferred embodiment, the solution of this application is implemented as follows: The PLC control cabinet 41 collects water pump outlet pressure data through a pressure sensor, obtains real-time flow data through a flow meter, and calculates the current output power by combining the current signal output by the frequency converter. The real-time operating load is mapped to a preset pump characteristic curve model. If the current operating point deviates from the boundary range of the high-efficiency zone, and the flow increment in the next period is predicted based on historical data to cause the load to exceed the limit, the control cabinet generates a switching command. Specifically, when the main pump operating load reaches 95% of the maximum value of the high-efficiency zone of the curve, the standby water pump is started and enters the preheating state. After the main pump outlet pressure drops to the switching threshold, a disturbance-free switching is performed. At the same time, the cumulative operating time is recorded and converted into an efficiency decay coefficient. Combined with the current pump body vibration data, an efficiency factor is generated. Each pump body is assigned a priority weight to form a dynamically updated operating queue. For example, the standby pump with the shortest cumulative operating time and the highest efficiency factor is activated first, while the main pump that has been running continuously for more than a preset time window is forcibly switched to the end of the queue.

[0108] Through the above technical solutions, this application achieves dynamic matching between pump operating load and equipment performance curves, avoiding energy waste and equipment damage caused by a single pump deviating from its high-efficiency range for extended periods. By employing a weighted priority queue mechanism, the pump switching process balances operating efficiency with equipment loss mitigation, effectively reducing the damage to the electrical system caused by start-up and shutdown current surges, while extending the overall service life of the pump unit. A pre-start strategy based on real-time load forecasting further ensures system pressure stability and eliminates the risk of pressure fluctuations during switching.

[0109] In some of the solutions mentioned above in this application, a regulation mechanism based on temperature and pressure feedback is proposed to optimize the operational stability of the condensate recovery and treatment unit. However, in this process, the traditional single-variable control method fails to consider the linkage effect of temperature and pressure, resulting in the inability to dynamically maintain the slightly subcooled and slightly positive pressure state at the pump inlet, which can easily lead to cavitation risk.

[0110] This application further proposes a method for PLC control cabinet 41 to couple and analyze the feedback signals from temperature transmitter 30 and pressure transmitter, and to adjust the opening of temperature control valve 27 and pressure regulating valve 3 in real time. This includes: constructing a two-dimensional temperature and pressure state diagram based on the real-time acquired data from temperature transmitter 30 and pressure transmitter. When the temperature is higher than the upper temperature threshold and the pump inlet pressure is lower than the lower pressure threshold, PLC control cabinet 41 simultaneously increases the opening of temperature control valve 27 and decreases the opening of pressure regulating valve 3. When the temperature is higher than the upper temperature threshold and the pump inlet pressure is higher than the upper pressure threshold, PLC control cabinet 41 increases the opening of temperature control valve 27 and expands the opening of pressure regulating valve 3. When the temperature is lower than the lower temperature threshold and the pump inlet pressure is lower than the lower pressure threshold, PLC control cabinet 41 decreases the opening of temperature control valve 27 and decreases the opening of pressure regulating valve 3. When the temperature is lower than the lower temperature threshold and the pump inlet pressure is higher than the upper pressure threshold, PLC control cabinet 41 simultaneously decreases the opening of temperature control valve 27 and expands the opening of pressure regulating valve 3. The PLC control cabinet 41 also adjusts the response speed based on the rate of temperature change and the rate of pressure change.

[0111] The temperature and pressure two-dimensional state diagram maps temperature and pressure data to the same coordinate system, forming four quadrants of operating status partitions. Each partition corresponds to a different valve combination regulation strategy; for example, the upper temperature threshold can be set to 90℃, and the lower pressure threshold can be set to 0.1MPa. The adjustment range of the opening of the temperature control valve 27 can be set to 20%-80%, and the adjustment step of the pressure regulating valve 3 is controlled within 5%. The response speed is dynamically adjusted according to the rate of change; when the temperature change rate exceeds 2℃ / min and the pressure change rate exceeds 0.05MPa / min, the adjustment cycle is shortened to 10 seconds.

[0112] Specifically, the construction of the two-dimensional temperature and pressure state diagram involves normalizing real-time temperature and pressure data to create coordinate points on a two-dimensional plane. The region where each coordinate point is located triggers the corresponding valve action. For example, when the detected temperature reaches 95℃ and the pump inlet pressure is 0.08MPa, the coordinate point falls into the first quadrant. At this point, the cooling water flow rate is increased to lower the condensate temperature, while the opening of pressure regulating valve 3 is reduced to increase the pump inlet pressure. When the temperature drops to 85℃ and the pressure rises to 0.15MPa, the coordinate point enters the fourth quadrant. At this point, the cooling water flow rate is reduced and the opening of pressure regulating valve 3 is increased to prevent excessive pressure from causing system overload. The response speed is adjusted by calculating the temperature and pressure change gradient over the past 30 seconds. When the gradient value exceeds a preset threshold, the control signal transmission frequency is increased to 1.5 times the original frequency to ensure the system quickly returns to a stable state. This dual-variable coupling control mechanism effectively maintains the slightly subcooled and slightly positive pressure conditions at the pump inlet, keeping the net positive suction head (NPSH) above 3m and stabilizing the condensate temperature within the 80-90℃ range.

[0113] As a preferred embodiment, the solution of this application is implemented as follows: The PLC control cabinet 41 receives real-time data from the temperature transmitter 30 and the pressure transmitter, and constructs a two-dimensional state coordinate system with temperature as the vertical axis and pump inlet pressure as the horizontal axis. This coordinate system is divided into four control quadrants. When the temperature reaches 85℃ and the pump inlet pressure is below 0.15MPa, the control program determines that it is in the first control quadrant. At this time, the opening of the temperature control valve 27 at the circulating water outlet 26 is simultaneously increased to 65% and the opening of the pressure regulating valve 3 is decreased to 30%. When the temperature rises to 90℃ and the pump inlet pressure exceeds 0.25MPa, the program determines that it has entered the second control quadrant, and the opening of the temperature control valve 27 is increased to 75% while the opening of the pressure regulating valve 3 is expanded to 45%. During the adjustment process, if the temperature change rate is detected to exceed 2℃ / s and the pressure change rate is detected to exceed 0.02MPa / s, the control program shortens the adjustment response cycle from 5 seconds to 2 seconds.

[0114] Through the above technical solution, this application achieves coordinated control of condensate temperature and pump inlet pressure, effectively maintaining a slightly subcooled and slightly positive pressure state at the pump inlet. By constructing a two-dimensional state diagram for multi-quadrant control, the pressure fluctuation and temperature mismatch problems caused by traditional single-variable regulation are solved, avoiding the risk of cavitation caused by sudden temperature rises. Adjustment based on the dynamic rate of change further enhances the system's adaptability to sudden operating conditions, ensuring a smooth transition during the regulation process.

[0115] In the above embodiments, a condensate tank with a separate collection chamber and a temperature and pressure control chamber is constructed. Combined with a level-lifting device, condensate automatically transitions from a low level to the heat exchange and pressure regulation zone, avoiding insufficient air chamber capacity due to equipment layout limitations. A water-to-water heat exchanger and a built-in flow-guiding and pressurizing device are arranged in the temperature and pressure control chamber. These, along with a temperature control valve on the cooling water path and a pressure regulating valve in the outlet water path, are coordinated by a PLC control cabinet to achieve dynamic regulation of condensate temperature and pump inlet pressure. The PLC control cabinet integrates multi-dimensional signals such as liquid level, temperature, pressure, and pump load, possessing pump group scheduling capabilities based on changing trends and temperature and pressure coupling regulation capabilities. It can adjust the start-stop strategies and operating windows of the main and standby pumps in real time under various operating conditions, and precisely regulate the cooling intensity and outlet back pressure, ensuring the pump inlet is always maintained in the optimal anti-cavitation range of "slight subcooling + slight positive pressure." Compared to traditional methods, this application solves the cavitation problem caused by space constraints, improves heat exchange efficiency, control accuracy, and intelligence level, and achieves high efficiency and stability of the condensate recovery system.

[0116] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program goods. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program goods embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0117] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program goods according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0118] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0119] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A condensate recovery and treatment unit with temperature and pressure regulation, characterized in that, include: A condensate tank is provided with a collection chamber and a temperature and pressure control chamber, which are connected by a partition with through holes. The collection chamber is provided with a condensate inlet, a safety valve, a pressure transmitter, a level gauge, and a level lifting device, which is used to lift the condensate to the temperature and pressure control chamber. A water-to-water heat exchanger is provided inside the temperature and pressure control chamber. The water-to-water heat exchanger is connected to the circulating water inlet and the circulating water outlet, and the circulating water outlet is equipped with a temperature control valve; the water-to-water heat exchanger is equipped with a flow guiding and pressurizing device, which is connected to the inlet of at least two water pumps, and the outlet of each water pump is sequentially connected to a check valve, a pressure regulating valve and a condensate outlet. A pressure sensor and a temperature sensor are installed between the water pump and the condensate tank. The PLC control cabinet is used to limit the operating pressure of the water pump based on the real-time pressure difference between the temperature and pressure control chamber and the inlet and outlet of the water pump; dynamically adjust the start-up and shutdown strategy and operating time window of the standby water pump based on the changes in liquid level, temperature and pressure over a preset period and in combination with load data; and couple and analyze the feedback signals from the temperature transmitter and pressure transmitter to adjust the opening of the temperature control valve and pressure regulating valve in real time. A local thermometer and a temperature transmitter are installed in the liquid phase section of the temperature and pressure control chamber, and the temperature transmitter signal is transmitted to the PLC control cabinet; When the PLC control cabinet limits the operating pressure of the water pump based on the real-time pressure difference between the temperature and pressure regulating chamber and the inlet and outlet of the water pump, it includes: Based on the pressure in the temperature and pressure control chamber, the pump inlet pressure, and the pump outlet pressure, the pump pressure rise range is obtained. This range is then compared to a differential pressure threshold, and the comparison result determines whether the pump is within a safe operating range. When the pump pressure rise range exceeds the differential pressure threshold, it is determined that the differential pressure exceeds the upper limit, and the PLC control cabinet sends an adjustment signal to the pressure regulating valve to limit the pump's operating pressure. When the PLC control cabinet dynamically adjusts the start-stop strategy and pump operating time window of the standby water pump based on the changes in liquid level, temperature, and pressure over a preset period and in conjunction with load data, it includes: The continuous monitoring values ​​of liquid level, temperature and pressure within a preset time period are processed by a sliding window to calculate the first difference and trend slope of the variables. When the average slope of a continuous downward or upward trend exceeds a slope threshold, and the water pump is in a switchable operating condition, the standby water pump is pre-started, and the switching is completed before the water pump load exceeds the limit; When the PLC control cabinet dynamically adjusts the start-stop strategy and pump operating time window of the standby water pump based on the changes in liquid level, temperature, and pressure over a preset period and in conjunction with load data, it also includes: The real-time operating load is calculated based on the current output power, outlet pressure, and flow rate of the water pump. The real-time operating load is compared with the high-efficiency range of the pump characteristic curve. If it deviates from the curve or the load is predicted to exceed the limit in the next period, the PLC control cabinet adjusts the operating window of the water pump and switches to the standby water pump. Meanwhile, a weighted priority queue is constructed based on the cumulative running time and efficiency factor of each pump, and the pumps are selected for operation according to the rotation priority.

2. The condensate recovery and treatment unit with temperature and pressure regulation according to claim 1, characterized in that, The liquid level raising device includes a flow guide cover and a flow guide pipe connected to the through hole of the collection chamber. The inlet of the flow guide pipe is located below the liquid level in the collection chamber, which is used to maintain a stable liquid flow of condensate in the temperature and pressure control chamber.

3. The condensate recovery and treatment unit with temperature and pressure regulation according to claim 1, characterized in that, A high-level filter is provided on the through-hole channel between the temperature and pressure control chamber and the collection chamber. The high-level filter is equipped with a flange cover and a drain valve. The drain valve is connected to the drain collection port. The high-level filter is used to filter impurities in the condensate.

4. The condensate recovery and treatment unit with temperature and pressure regulation according to claim 1, characterized in that, The water-to-water heat exchanger is equipped with a butterfly valve at the circulating water inlet and a temperature control valve at the circulating water outlet. The temperature control valve is connected to the PLC control cabinet via a signal line.

5. The condensate recovery and treatment unit with temperature and pressure regulation according to claim 3, characterized in that, The top of the condensate tank is equipped with an exhaust pipe, which is connected to a vent valve and an automatic exhaust valve. The exhaust gas is released through the sewage collection port.

6. The condensate recovery and treatment unit with temperature and pressure regulation according to claim 5, characterized in that, When the PLC control cabinet limits the operating pressure of the water pump based on the real-time pressure difference between the temperature and pressure regulating chamber and the inlet and outlet of the water pump, it also includes: The PLC control cabinet calculates the short-term pressure difference trend based on the recent time-period pressure difference sequence and the water pump operating status using a prediction algorithm. When the prediction result indicates that the water pump outlet pressure continues to rise and approaches the limit, the PLC control cabinet adjusts the opening of the pressure regulating valve.

7. The condensate recovery and treatment unit with temperature and pressure regulation according to claim 1, characterized in that, The PLC control cabinet performs coupled analysis of the feedback signals from the temperature transmitter and pressure transmitter, and adjusts the opening of the temperature control valve and pressure regulating valve in real time, including: A two-dimensional temperature and pressure state diagram is constructed based on the real-time data collected by the temperature transmitter and pressure transmitter. When the temperature is higher than the upper temperature threshold and the pressure before the pump is lower than the lower pressure threshold, the PLC control cabinet simultaneously increases the opening of the temperature control valve and decreases the opening of the pressure regulating valve. When the temperature is higher than the upper temperature threshold and the pressure before the pump is higher than the upper pressure threshold, the PLC control cabinet increases the opening of the temperature control valve and expands the opening of the pressure regulating valve. When the temperature is below the lower threshold temperature and the pressure before the pump is below the lower threshold pressure, the PLC control cabinet reduces the opening of the temperature control valve and the pressure regulating valve. When the temperature is below the lower temperature threshold and the pressure before the pump is above the upper pressure threshold, the PLC control cabinet simultaneously reduces the opening of the temperature control valve and expands the opening of the pressure regulating valve. The PLC control cabinet also adjusts the response speed based on the rate of temperature change and the rate of pressure change.

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