A high-temperature heat pump steam unit system and method based on petrochemical waste heat

Abstract

This invention discloses a high-temperature heat pump steam unit system and method based on petrochemical waste heat, belonging to the field of petrochemical waste heat utilization technology. The system includes a waste heat utilization loop, a steam generation loop, and a working fluid circulation and separation loop. In the waste heat utilization loop, evaporators E1 and E2 are connected in series to achieve stepped cooling of waste heat; in the steam generation loop, condensers C1, C2, and C3 are connected in series to achieve stepped heating of makeup water; the working fluid circulation and separation loop is equipped with two-phase separators S1 and S2 and a regenerator to achieve staged separation of the mixed working fluid and control of suction superheat. This invention reduces irreversible heat exchange losses by more than 20% through bidirectional temperature sliding matching on the evaporation and condensation sides; it cools waste water at 80-90℃ to 40-50℃, increasing the waste heat recovery rate by more than 25%.

Description

Technical Field

[0001] This invention belongs to the field of petrochemical waste heat utilization technology, specifically a high-temperature heat pump steam unit system and method based on petrochemical waste heat. Background Technology

[0002] The petrochemical industry is a vital pillar of the national economy, but it is also a high-energy-consuming sector. During petrochemical production, a large amount of low- and medium-temperature waste heat (especially hot water or low-pressure steam around 80°C) is directly released into the environment, resulting in enormous energy waste. Statistics show that waste heat resources in the petrochemical industry account for approximately 15%-30% of its total energy consumption, with low-temperature waste heat below 100°C accounting for the largest proportion and being the most difficult to recover and utilize.

[0003] Heat pump technology is an effective means of recovering low- to medium-temperature waste heat and improving its quality (to produce higher-temperature steam). However, existing high-temperature heat pump systems based on waste heat recovery mainly suffer from the following technical problems: 1. Traditional heat pump systems typically use a single working fluid or a simple mixture of working fluids to exchange heat with heat sources and heat sinks in the evaporator and condenser. Since the phase change process of the working fluid is approximately isothermal, while the cooling process of the waste water and the heating process of the water to be heated both involve significant temperature changes, the temperature matching between the two is poor, resulting in large irreversible heat exchange losses and a low system coefficient of performance (COP). 2. Existing systems mostly adopt a single-stage evaporation structure, such as CN114135916A, where the working fluid absorbs waste heat at a constant temperature. When the waste water temperature drops from 80℃ to 55℃ or even lower, the single evaporation temperature cannot simultaneously meet the heat exchange requirements of the high-temperature and low-temperature sections, resulting in insufficient waste heat recovery and a still high discharge water temperature. 3. In high-temperature heat pump systems, the working fluid at the evaporator outlet is often saturated or nearly saturated. Directly entering the compressor can easily lead to liquid slugging risk, such as CN218645770U, which affects the reliability and lifespan of the compressor. The traditional solution is to increase the heat exchange area of ​​the evaporator or adopt a superheated section design, but this will increase the system cost and volume.

[0004] To address the aforementioned issues, it is necessary to develop a high-temperature heat pump steam unit system that can achieve deep waste heat recovery, efficient heat exchange matching, and reliable operation. Summary of the Invention

[0005] The technical problem to be solved by this invention is: how to provide a high-temperature heat pump steam unit system that can achieve deep waste heat recovery, efficient heat exchange matching and reliable operation.

[0006] To solve the above-mentioned technical problems, the inventors, through practice and summarization, derived the technical solution of this invention, which adopts the following technical solution: A high-temperature heat pump steam unit system based on petrochemical waste heat includes: Waste heat recovery circuits include: Petrochemical waste heat input pipe, petrochemical waste heat discharge pipe; Evaporators E1 and E2 are connected in series. The hot side inlet of evaporator E1 is connected to the petrochemical waste heat input pipe, and the hot side outlet of evaporator E2 is connected to the petrochemical waste heat discharge pipe. The steam generation circuit includes: Water inlet pipe and steam pipe; Condensers C1, C2, and C3 are connected in series. The water inlet pipe is connected to the cold side inlet of condenser C3, and the steam pipe is connected to the cold side outlet of condenser C1. The working fluid circulation and separation loop includes: The two-phase separator S1 has its two-phase inlet connected to the hot side outlet of condenser C1, its gas phase outlet connected to the hot side inlet of condenser C2, and its liquid phase outlet connected to the cold side inlet of evaporator E1 via a throttle valve. The two-phase separator S2 has its two-phase inlet connected to the hot-side outlet of condenser C2, its gas phase outlet connected to the hot-side inlet of condenser C3, and its liquid phase outlet connected to the hot-side outlet of condenser C3. The liquid phase outlet is then connected to the cold-side inlet of evaporator E2 via throttle valve II. The compressor has its suction port connected to the cold side outlet of evaporator E1 and the cold side outlet of evaporator E2, and its discharge port connected to the hot side inlet of condenser C1.

[0007] In the aforementioned high-temperature heat pump steam unit system based on petrochemical waste heat, the working fluid circulation and separation loop also includes a regenerator; The liquid phase outlet of the two-phase separator S1 is connected to the hot side inlet of the regenerator, and the hot side outlet of the regenerator is connected to the cold side inlet of the evaporator E1 via a throttle valve. The cold-side outlets of evaporators E1 and E2 are connected to the cold-side inlet of the regenerator via pipelines. The cold-side outlet of the regenerator is connected to the suction port of the compressor.

[0008] In the aforementioned high-temperature heat pump steam unit system based on petrochemical waste heat, a scale filter is installed at the cold side inlet of the condenser C1.

[0009] In the aforementioned high-temperature heat pump steam unit system based on petrochemical waste heat, a switch valve one is installed on the cold side inlet side of the condenser C2, and a switch valve two is installed on the cold side outlet side. A side branch pipe is led out between the switch valve one and the cold side outlet of the condenser C3. One end of the side branch pipe is connected between the scale filter and the switch valve two. The switch valve three is installed on the side branch pipe one. A second side branch pipe is led out between the first switch valve and the cold side inlet of the condenser C2. One end of the second side branch pipe is connected between the second switch valve and the cold side outlet of the condenser C2. A fourth switch valve is installed on the second side branch pipe.

[0010] In the aforementioned high-temperature heat pump steam unit system based on petrochemical waste heat, a switch valve five is installed on the hot side inlet side of the condenser C2, and a switch valve six is ​​installed on the hot side outlet side. A side branch pipe three is led out between the gas phase outlet side of the switching valve five and the two-phase separator S1. One end of the side branch pipe three is connected between the switching valve six and the two-phase inlet of the two-phase separator S2. A switching valve seven is installed on the side branch pipe three. A side branch pipe four is led out between the switch valve six and the hot side outlet of the condenser C2. One end of the side branch pipe four is connected between the switch valve five and the gas phase outlet of the two-phase separator S1. A switch valve eight is installed on the side branch pipe four.

[0011] In the aforementioned high-temperature heat pump steam unit system based on petrochemical waste heat, the condenser C2 includes a shell and a tube-side inner wall cleaning component. The shell is provided with a working fluid inlet, a working fluid outlet, a water inlet, and a water outlet. The water inlet and water outlet are distributed at both ends of the shell. Both ends of the shell are provided with partition plates. The two sets of partition plates are provided with corresponding holes for welding and installing cold-side pipes. The working fluid inlet is distributed on the upper side of one end of the shell, and the working fluid outlet is distributed on the lower side of the shell away from the working fluid inlet. The shell is equipped with a spiral guide plate with several through holes evenly distributed on it. The cold side pipes are inserted through the corresponding through holes. The pipe-side inner wall cleaning component is installed at the end of the cold side pipes. The pipe-side inner wall cleaning component has a structure for cleaning dirt from the inner wall of the cold side pipes.

[0012] In the aforementioned high-temperature heat pump steam unit system based on petrochemical waste heat, the inner wall cleaning component of the tube includes an installation body installed at both ends of the cold side pipe and a cleaning body movably distributed within the installation body. An interceptor is provided at the end of the installation body away from the cold side pipe, and multiple side openings are distributed circumferentially on the installation body. The opening size of the side openings is smaller than the size of the cleaning body.

[0013] In the aforementioned high-temperature heat pump steam unit system based on petrochemical waste heat, the cleaning body includes an intermediate sleeve and a brush body spirally distributed on the outside of the intermediate sleeve. Both ends of the intermediate sleeve are provided with conical covers, and a deformable cover is provided at the end of the conical cover away from the intermediate sleeve. An elastic pin is installed on the conical cover. A follower rod is movably installed inside the intermediate sleeve. Both ends of the follower rod are connected to the inner walls of the two sets of deformable covers respectively. A constraint ring groove adapted to the elastic pin is provided on the follower rod. An extrusion component is installed at the end of the interceptor that faces the deformable shield.

[0014] In the aforementioned high-temperature heat pump steam unit system based on petrochemical waste heat, the evaporators E1 and E2 are plate heat exchangers or shell-and-tube heat exchangers, and the heat exchange area of ​​evaporator E1 is larger than that of evaporator E2.

[0015] A control method for a high-temperature heat pump steam unit system based on petrochemical waste heat, comprising the following steps: Step 1, Waste Heat Recovery Stage: Petrochemical waste hot water at 80-90℃ flows sequentially through evaporator E1 and evaporator E2. After heat exchange on the hot side of evaporator E1, it is cooled to 65-70℃. After heat exchange on the hot side of evaporator E2, it is cooled to 40-50℃ and then discharged. The working fluid absorbs heat and evaporates from 55-60℃ to 60-65℃ on the cold side of evaporator E1, and absorbs heat and evaporates from 35-40℃ to 40-45℃ on the cold side of evaporator E2. After the two working fluids merge at the outlet, the temperature reaches 55-60℃ and enters the cold side of the regenerator. Step 2, Reheating and Overheating Stage: The combined 55-60℃ gas mixture absorbs heat from the hot side liquid in the cold side of the regenerator, and enters the compressor after being heated by 5-15℃. Step 3, Compression Stage: The compressor compresses the mixed gas to a high temperature and high pressure state, and the exhaust temperature reaches 140-160℃, which is then discharged into the hot side of the condenser C1. Step 4, Staged condensation and steam generation: A high-temperature, high-pressure mixed working fluid of 140-160℃ flows sequentially through the hot side of condensers C1, C2, and C3, and releases heat through staged condensation. Among them, the hot side of condenser C1 cools down from 140-160℃ to 125-135℃, the hot side of condenser C2 cools down from 125-135℃ to 100-110℃, and the hot side of condenser C3 cools down from 100-110℃ to 75-85℃. The makeup water at 20-30℃ flows sequentially through the cold side of condenser C3, condenser C2 and condenser C1, and is heated in stages. The cold-side outlet water temperature of condenser C3 is 50-65℃, the cold-side outlet water temperature of condenser C2 is 80-90℃, and the cold-side outlet of condenser C1 generates saturated steam at 120-130℃, which is then output through the steam pipe. Step 5: Component separation and reheating / subcooling stage: The high-boiling-point liquid phase separated in the two-phase separator S1 at 125-135℃ enters the hot side of the regenerator, where it releases heat and cools down to 80-90℃. Then, it is depressurized and cooled down to 55-60℃ through the throttling valve and flows back to the cold side inlet of the evaporator E1. The 100-110℃ medium-boiling-point liquid phase separated in the two-phase separator S2 is mixed with the 75-85℃ low-boiling-point liquid phase at the outlet of the condenser C3. After mixing, the temperature of the mixture is 85-95℃. The mixture is then depressurized and cooled to 35-40℃ through the second throttle valve and enters the cold side inlet of the evaporator E2. The working fluid absorbs heat in evaporators E1 and E2 respectively, and then merges at the outlet before entering the cold side of the regenerator to complete the cycle. Step 6, Tube cleaning: The state switches between state one and state two every 2-4 hours. State 1: Switch valves 7 and 8 are closed, and switch valves 5 and 6 are open. The medium and low boiling point gas phase mixed working fluid enters the hot side of condenser C2 through switch valve 5 to release heat, and enters the two-phase separator S2 through switch valve 6. Switch valves three and four are in the closed state, while switch valves one and two are in the open state. Water heated by condenser C3 enters the cold side of condenser C2 through switch valve one to absorb heat, and then enters the scale filter through switch valve two. State Two: Switch valves five and six are in the closed state, while switch valves seven and eight are in the open state. The medium and low boiling point gas phase mixed working fluid enters the hot side of condenser C2 through switch valve seven to release heat, and then enters the two-phase separator S2 through switch valve eight. Switch valve one and switch valve two are in the closed state, while switch valve three and switch valve four are in the open state. Water heated by condenser C3 enters the cold side of condenser C2 through switch valve three to absorb heat, and then enters the scale filter through switch valve four.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention, by setting up evaporators E1 and E2 in series, enables the non-azeotropic working fluid to generate a temperature glide during evaporation, which matches the cooling curve of petrochemical waste water from 80-90℃ to 40-50℃; simultaneously, by setting up condensers C1, C2, and C3 in series, the working fluid generates a temperature glide during condensation, which matches the heating curve of makeup water from room temperature to 120-130℃ steam; the bidirectional temperature matching on the evaporation and condensation sides significantly reduces irreversible losses during heat exchange, and the system performance coefficient (COP) can be improved by more than 20% compared to traditional single-stage or simple mixed working fluid systems; 2. This invention adopts a two-stage series evaporation structure. The high-boiling-point working fluid preferentially exchanges heat with the high-temperature waste water, and the low-boiling-point working fluid then exchanges heat with the cooled waste water, forming a cascade utilization. Combined with the component regulation function of the two-stage two-phase separator, the evaporator E2 can effectively recover the waste heat in the low-temperature section, and the petrochemical waste water / steam is cooled from 80-90℃ to 40-50℃ before being discharged. Compared with the traditional system, the waste heat emission loss is significantly reduced, and the waste heat recovery rate is increased by more than 25%. 3. This invention includes a regenerator installed between the evaporator outlet and the compressor suction port. The liquid phase outlet of the two-phase separator S1 enters the hot side of the regenerator. After absorbing heat in the evaporator, the working fluid enters the cold side of the regenerator, adsorbs heat from the hot side liquid, and is heated by 5-15°C before entering the compressor. This ensures that the compressor has sufficient suction superheat, effectively preventing the risk of liquid slugging. At the same time, the regenerator subcools the liquid before the throttle valve, increasing the heating capacity per unit mass of working fluid and further improving the system energy efficiency. 4. This invention installs a scale filter at the cold-side inlet of condenser C1 and provides bypass switching valve groups on both the cold and hot sides of condenser C2. When the heat exchange efficiency of condenser C2 decreases due to scaling, the condenser C2 can be isolated from the system and back-flushed by switching the opening and closing states of valves one to eight, thus completing the descaling operation without stopping the system. Compared with the traditional system that requires shutdown for disassembly and cleaning, this invention significantly reduces maintenance downtime and improves the continuous operation rate of the system. 5. The condenser of this invention is equipped with a spiral guide plate with through holes, which can guide the shell-side working fluid into a spiral plug flow, greatly reducing the flow resistance of the shell-side fluid, reducing the flow dead zone, improving the heat transfer coefficient, and alleviating the scaling rate. Under high Reynolds numbers, the heat exchange tubes are less prone to failure due to fluid-induced vibration and weld seams at the cold-side pipe joints. The cold-side pipes are installed in the through holes of the spiral guide plate. The inner wall cleaning component of the tubes is installed at the end of the cold-side pipes. The cleaning body is driven by the power of the water flow to reciprocate within the tubes. The brush body on the outer side of the middle sleeve can automatically clean the dirt on the inner wall of the tubes. This structure can achieve online automatic cleaning of the tubes without external power, effectively solving the problem of performance degradation caused by scaling after long-term operation of the heat exchanger. 6. This invention uses plate heat exchangers or shell-and-tube heat exchangers as evaporators E1 and E2, with the heat exchange area of ​​E1 being larger than that of E2. This design takes into account the difference in heat load borne by the two evaporators: E1 handles the waste heat in the high-temperature section, with a large heat exchange temperature difference and high heat flux density, requiring a larger heat exchange area; E2 handles the waste heat in the low-temperature section, with a relatively smaller heat load. Configuring the heat exchange area as needed avoids material waste and reduces system manufacturing costs. 7. This invention, through the synergistic effect of staged compression and staged condensation, can improve the grade of petrochemical waste water at 80-90℃ and stably produce saturated steam at 120-130℃. Steam in this temperature range can be widely used in processes such as distillation, drying, and reactor heating in the petrochemical industry, effectively replacing coal-fired or gas-fired boilers and achieving the dual goals of waste heat recovery and carbon emission reduction. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the high-temperature heat pump steam unit system structure of this application.

[0018] Figure 2 This is a diagram showing the operating condition of the high-temperature heat pump steam unit system in State 1 of this application.

[0019] Figure 3 This is a diagram showing the operating condition of the high-temperature heat pump steam unit system in state two of this application.

[0020] Figure 4 This is a schematic diagram of the condenser C2.

[0021] Figure 5 This is a side view of condenser C2.

[0022] Figure 6 This is a schematic diagram of the internal structure of condenser C2.

[0023] Figure 7 This is a side view of the end face of the partition plate.

[0024] Figure 8 This is a schematic diagram of the internal cleaning component for the tube.

[0025] Figure 9 This is a structural diagram of the cleaned body.

[0026] Figure 10 This is a cross-sectional view of the internal cleaning component of the tube.

[0027] Figure 11 for Figure 10 A magnified view of a portion of point A in the middle.

[0028] Figure 12 This is a structural diagram of a spiral guide plate.

[0029] In the diagram: 10. Petrochemical waste heat input pipe; 20. Petrochemical waste heat discharge pipe; 30. Evaporator E1; 40. Evaporator E2; 50. Water inlet pipe; 60. Steam pipe; 70. Condenser C1; 80. Condenser C2; 90. Condenser C3; 100. Two-phase separator S1; 110. Two-phase separator S2; 120. Compressor; 130. Regenerator; 140. Filter; 81. Shell; 82. Tube-side inner wall cleaning component; 83. Partition plate; 84. Cold side piping; 85. Spiral guide plate; 841. Mounting body; 842. Cleaning body; 843. Side opening; 844. Conical shroud; 845. Deformation shroud; 846. Intermediate sleeve; 847. Brush body; 848. Follower rod; 849. Constraint ring groove; 8410. Extrusion component. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0031] Example 1: As Figure 1 As shown, a high-temperature heat pump steam unit system based on petrochemical waste heat includes: Waste heat recovery circuits include: Petrochemical waste heat input pipe 10, petrochemical waste heat discharge pipe 20; Evaporators E1 30 and E2 40 are connected in series. The hot side inlet of evaporator E1 30 is connected to the petrochemical waste heat input pipe 10, and the hot side outlet of evaporator E2 40 is connected to the petrochemical waste heat discharge pipe 20. Evaporator E1 30 and evaporator E2 40 are plate heat exchangers or shell-and-tube heat exchangers, and the heat exchange area of ​​evaporator E1 30 is larger than that of evaporator E2 40. The steam generation circuit includes: Water inlet pipe 50 and steam pipe 60; The condensers C1 70, C2 80 and C3 90 are connected in series. The water inlet pipe 50 is connected to the cold side inlet of the condenser C3 90, and the steam pipe 60 is connected to the cold side outlet of the condenser C1 70. The working fluid circulation and separation loop includes: The two-phase separator S1 100 has its two-phase inlet connected to the hot side outlet of the condenser C1 70, its gas phase outlet connected to the hot side inlet of the condenser C2 80, and its liquid phase outlet connected to the cold side inlet of the evaporator E1 30 via a throttle valve. The two-phase separator S2 110 has its two-phase inlet connected to the hot side outlet of condenser C2 80, its gas phase outlet connected to the hot side inlet of condenser C3 90, and its liquid phase outlet connected to the hot side outlet of condenser C3 90. The liquid phase outlet is connected to the cold side inlet of evaporator E2 40 via throttle valve II. The compressor 120 has its suction port connected to the cold side outlet of evaporator E1 30 and the cold side outlet of evaporator E2 40, and its discharge port connected to the hot side inlet of condenser C1 70.

[0032] Working principle: The waste hot water or exhaust gas from the petrochemical plant passes through the petrochemical waste heat input pipe 10 and then through the hot side of the evaporator E1 30 and the evaporator E2 40 to release heat, and finally is discharged from the petrochemical waste heat discharge pipe 20. Room temperature water is heated by absorbing heat step by step through the cold side of condenser C3 90, condenser C2 80 and condenser C1 70 via inlet pipe 50, and finally produces steam through steam pipe 60. The mixed working fluid releases heat on the hot side of condenser C1 70 and then enters two-phase separator S1 100. The separated high-boiling-point liquid working fluid absorbs heat from the cold side of evaporator E1 30 through throttling valve one. The gaseous mixed working fluid releases heat from the gas phase outlet of two-phase separator S1 100 through the hot side of condenser C2 80 and then enters two-phase separator S2 110. The separated low-boiling-point gaseous working fluid releases heat on the hot side of condenser C3 90 and becomes low-boiling-point liquid working fluid. Finally, it mixes with the medium-boiling-point liquid working fluid and enters the cold side of evaporator E2 40 through throttling valve two to absorb heat. After mixing with the high-boiling-point gaseous working fluid, it returns to the suction port of compressor 120 to complete the cycle.

[0033] Example 2: In Example 1 above, as Figure 1 As shown, the working fluid circulation and separation loop also includes a regenerator 130; The liquid phase outlet of the two-phase separator S1 100 is connected to the hot side inlet of the regenerator 130, and the hot side outlet of the regenerator 130 is connected to the cold side inlet of the evaporator E1 30 via a throttle valve. The cold-side outlets of evaporators E1 30 and E2 40 are connected to the cold-side inlet of regenerator 130 via pipelines. The cold-side outlet of regenerator 130 is connected to the suction port of compressor 120.

[0034] The high-boiling-point liquid working fluid enters the hot side of the regenerator 130 to release heat, while the low, medium and high-boiling-point mixed working fluids are mixed and then enter the cold side of the regenerator 130 to absorb heat. Finally, they enter the suction port of the compressor 120, ensuring that the compressor 120 has sufficient suction superheat and effectively preventing the risk of liquid slugging.

[0035] Example 3: In Example 2 above, as Figure 2 and Figure 3 As shown, a scale filter 140 is installed at the cold side inlet of the condenser C1 70; The condenser C2 80 is equipped with a switch valve one on the cold side inlet and a switch valve two on the cold side outlet; A side branch pipe is led out between the first switch valve and the cold side outlet of the condenser C3 90. One end of the side branch pipe is connected between the scale filter 140 and the second switch valve. A third switch valve is installed on the side branch pipe. A second side branch pipe is led out between the first switch valve and the cold side inlet of the condenser C2 80. One end of the second side branch pipe is connected between the second switch valve and the cold side outlet of the condenser C2 80. A fourth switch valve is installed on the second side branch pipe.

[0036] The condenser C2 80 is equipped with a five-way valve on the hot side inlet and a six-way valve on the hot side outlet. A side branch pipe three is led out between the gas phase outlet side of the switching valve five and the two-phase separator S1 100. One end of the side branch pipe three is connected between the switching valve six and the two-phase inlet of the two-phase separator S2 110. A switching valve seven is installed on the side branch pipe three. Side branch pipe four is led out between switch valve six and the hot side outlet of condenser C2 80. One end of side branch pipe four is connected between switch valve five and the gas phase outlet of two-phase separator S1 100. Switch valve eight is installed on side branch pipe four.

[0037] The state switches between state one and state two every 2-4 hours.

[0038] State 1: Switch valves 7 and 8 are closed, and switch valves 5 and 6 are open. The medium and low boiling point gas phase mixed working fluid enters the hot side of condenser C2 80 through switch valve 5 to release heat, and enters the two-phase separator S2 110 through switch valve 6. Switch valves three and four are in the closed state, while switch valves one and two are in the open state. Water heated by condenser C3 90 enters the cold side of condenser C2 80 through switch valve one to absorb heat, and then enters the scale filter 140 through switch valve two.

[0039] State 2: Switch valves 5 and 6 are closed, and switch valves 7 and 8 are open. The medium and low boiling point gas phase mixed working fluid enters the hot side of condenser C2 80 through switch valve 7 to release heat, and enters the two-phase separator S2 110 through switch valve 8. Switch valve 1 and switch valve 2 are in the closed state, and switch valve 3 and switch valve 4 are in the open state. Water heated by condenser C3 90 enters the cold side of condenser C2 80 through switch valve 3 to absorb heat, and then enters the scale filter 140 through switch valve 4.

[0040] To achieve online automatic cleaning of scale buildup on the inner walls of the tubes, research revealed that scale buildup is more likely to occur in the cold-side tubes 84 of condenser C2 80. While a similar design could be implemented in condenser C3 90, structural improvements were made to condenser C2 80, such as... Figures 4 to 12 As shown, the specific improvements are as follows: The condenser C2 80 includes a shell 81 and a tube-side inner wall cleaning component 82. The shell 81 is provided with a working fluid inlet, a working fluid outlet, a water inlet, and a water outlet. The water inlet and water outlet are distributed at both ends of the shell 81. Both ends of the shell 81 are provided with partition plates 83. The two sets of partition plates 83 are provided with corresponding holes for welding and installing cold-side pipes 84. The working fluid inlet is distributed on the upper side of one end of the shell 81, and the working fluid outlet is distributed on the lower side of the shell 81 away from the working fluid inlet. A spiral guide plate 85 is installed inside the housing 81. Several through holes are evenly distributed on the spiral guide plate 85. The cold side pipe 84 passes through the corresponding through holes. The pipe inner wall cleaning component 82 is installed at the end of the cold side pipe 84. The pipe inner wall cleaning component 82 has a structure for cleaning dirt on the inner wall of the cold side pipe 84.

[0041] The inner wall cleaning component 82 includes a mounting body 841 installed at both ends of the cold side pipe 84 and a cleaning body 842 movably distributed within the mounting body 841. An interceptor is provided at the end of the mounting body 841 away from the cold side pipe 84. Multiple side openings 843 are distributed circumferentially on the mounting body 841. The opening size of the side openings 843 is smaller than the size of the cleaning body 842 to prevent the cleaning body 842 from detaching from the inside.

[0042] The cleaning body 842 includes an intermediate sleeve 846 and a brush body 847 spirally distributed on the outside of the intermediate sleeve 846. Both ends of the intermediate sleeve 846 are provided with conical covers 844, which are made of high-temperature resistant hard material. The end of the conical cover 844 away from the intermediate sleeve 846 is provided with a deformable cover 845, which is made of high-temperature resistant flexible material. An elastic pin is installed on the conical cover 844. A follower rod 848 is movably installed inside the intermediate sleeve 846. Both ends of the follower rod 848 are respectively connected to the inner walls of the two sets of deformable covers 845. A constraint ring groove 849 adapted to the elastic pin is provided on the follower rod 848. An extrusion component 8410 is installed at the end of the interceptor facing the deformable shield 845.

[0043] During the transition between states one and two, the water pressure on the cold side enters through the side port 843 and pressurizes the brush body 847. The brush body 847 enters the cold side pipe 84. Due to the water pressure, the brush body 847 rotates and moves to the other end. At the same time, the water pressure also acts on the end of the cleaning body 842, thereby increasing the propulsion force. During this period, the brush body 847 cleans the dirt from the inner wall and sends it with the water to the filter 140 for filtration before entering the cold side of the condenser C1 70. Inside the mounting body 841 at the other end, the deformable cover 845 at the head abuts against the extrusion piece 8410 and elastically deforms inward, causing the deformable cover 845 at the other end to return to its convex state. An elastic pin presses the internal follower rod 848 to prevent the concave deformable cover 845 from returning to its shape. At this time, the cleaning body 842 only needs to wait for the next water flow reversal.

[0044] A control method for a high-temperature heat pump steam unit system based on petrochemical waste heat, comprising the following steps: Step 1, Waste Heat Recovery Stage: Petrochemical waste hot water at 80-90℃ flows sequentially through evaporator E1 30 and evaporator E2 40. After heat exchange on the hot side of evaporator E1 30, the temperature drops to 65-70℃. After heat exchange on the hot side of evaporator E2 40, the temperature drops to 40-50℃ before being discharged. The working fluid absorbs heat and evaporates from 55-60℃ to 60-65℃ on the cold side of evaporator E1 30, and absorbs heat and evaporates from 35-40℃ to 40-45℃ on the cold side of evaporator E2 40. After the two working fluids merge at the outlet, the temperature reaches 55-60℃ and enters the cold side of regenerator 130. Step 2, Reheating and Overheating Stage: The combined 55-60℃ mixed gas absorbs heat from the hot side liquid in the cold side of the regenerator 130, and after being heated by 5-15℃, it enters the compressor 120. Step 3, Compression Stage: Compressor 120 compresses the mixed gas to a high temperature and high pressure state, with the exhaust temperature reaching 140-160℃, and discharges it into the hot side of condenser C1 70; Step 4, Staged condensation and steam generation: A high-temperature, high-pressure mixed working fluid of 140-160℃ flows sequentially through the hot side of condenser C1 70, condenser C2 80 and condenser C390, and releases heat through staged condensation. Among them, the hot side of condenser C1 70 cools down from 140-160℃ to 125-135℃, the hot side of condenser C2 80 cools down from 125-135℃ to 100-110℃, and the hot side of condenser C3 90 cools down from 100-110℃ to 75-85℃. The makeup water at 20-30℃ flows sequentially through the cold side of condenser C3 90, condenser C2 80 and condenser C1 70, and is heated in stages. The cold-side outlet water temperature of condenser C3 90 is 50-65℃, the cold-side outlet water temperature of condenser C2 80 is 80-90℃, and the cold-side outlet of condenser C1 70 generates saturated steam at 120-130℃, which is output through steam pipe 60. Step 5: Component separation and reheating / subcooling stage: The high-boiling-point liquid phase separated in the two-phase separator S1 100 at 125-135℃ enters the hot side of the regenerator 130, where it releases heat and cools down to 80-90℃. Then, it is depressurized and cooled down to 55-60℃ through the throttling valve and flows back to the cold side inlet of the evaporator E1 30. The 100-110℃ medium-boiling-point liquid phase separated in the two-phase separator S2 110 is mixed with the 75-85℃ low-boiling-point liquid phase at the outlet of the condenser C3 90. After mixing, the temperature of the mixture is 85-95℃. The mixture is then depressurized and cooled to 35-40℃ through the second throttle valve and enters the cold side inlet of the evaporator E2 40. The working fluid absorbs heat in evaporators E1 30 and E2 40 respectively, and after merging at the outlet, it enters the cold side of regenerator 130 to complete the cycle; Step 6, Tube cleaning: The state switches between state one and state two every 2-4 hours. State 1: Switch valves 7 and 8 are closed, and switch valves 5 and 6 are open. The medium and low boiling point gas phase mixed working fluid enters the hot side of condenser C2 80 through switch valve 5 to release heat, and enters the two-phase separator S2 110 through switch valve 6. Switch valves three and four are in the closed state, while switch valves one and two are in the open state. Water heated by condenser C3 90 enters the cold side of condenser C2 80 through switch valve one to absorb heat, and then enters the scale filter 140 through switch valve two. State Two: Switch valves five and six are in the closed state, while switch valves seven and eight are in the open state. The medium and low boiling point gas phase mixed working fluid enters the hot side of the condenser C2 80 through switch valve seven to release heat, and then enters the two-phase separator S2 110 through switch valve eight. Switch valve 1 and switch valve 2 are in the closed state, and switch valve 3 and switch valve 4 are in the open state. Water heated by condenser C3 90 enters the cold side of condenser C2 80 through switch valve 3 to absorb heat, and then enters the scale filter 140 through switch valve 4.

[0045] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. The substitutions may be replacements of some structures, devices, or method steps, or they may be complete technical solutions. Equivalent substitutions or modifications made to the technical solutions and inventive concepts of the present invention should all be covered within the scope of protection of the present invention.

Claims

1. A high-temperature heat pump steam unit system based on petrochemical waste heat, characterized in that, include: Waste heat recovery circuits include: Petrochemical waste heat input pipe (10), petrochemical waste heat discharge pipe (20); Evaporators E1 (30) and E2 (40) are connected in series. The hot side inlet of evaporator E1 (30) is connected to the petrochemical waste heat input pipe (10), and the hot side outlet of evaporator E2 (40) is connected to the petrochemical waste heat discharge pipe (20). The steam generation circuit includes: Water inlet pipe (50) and steam pipe (60); The condensers C1 (70), C2 (80) and C3 (90) are connected in series. The water inlet pipe (50) is connected to the cold side inlet of the condenser C3 (90), and the steam pipe (60) is connected to the cold side outlet of the condenser C1 (70). The working fluid circulation and separation loop includes: Two-phase separator S1 (100) has its two-phase inlet connected to the hot side outlet of condenser C1 (70), its gas phase outlet connected to the hot side inlet of condenser C2 (80), and its liquid phase outlet connected to the cold side inlet of evaporator E1 (30) via throttle valve 1. The two-phase separator S2 (110) has its two-phase inlet connected to the hot side outlet of condenser C2 (80), its gas phase outlet connected to the hot side inlet of condenser C3 (90), and its liquid phase outlet connected to the hot side outlet of condenser C3 (90). The liquid phase outlet is connected to the cold side inlet of evaporator E2 (40) via throttle valve II. The compressor (120) has its suction port connected to the cold side outlet of the evaporator E1 (30) and the cold side outlet of the evaporator E2 (40), and its discharge port connected to the hot side inlet of the condenser C1 (70). The working fluid circulation and separation loop also includes a regenerator (130). The liquid phase outlet of the two-phase separator S1 (100) is connected to the hot side inlet of the regenerator (130), and the hot side outlet of the regenerator (130) is connected to the cold side inlet of the evaporator E1 (30) via a throttle valve. The cold-side outlets of evaporators E1 (30) and E2 (40) are connected to the cold-side inlet of the regenerator (130) via pipelines. The cold-side outlet of the regenerator (130) is connected to the suction port of the compressor (120).

2. The high-temperature heat pump steam unit system based on petrochemical waste heat according to claim 1, characterized in that, The condenser C1 (70) is equipped with a scale filter (140) at its cold side inlet.

3. A high-temperature heat pump steam unit system based on petrochemical waste heat according to claim 2, characterized in that, The condenser C2 (80) is equipped with a switch valve one on the cold side inlet and a switch valve two on the cold side outlet; A side branch pipe is led out between the first switch valve and the cold side outlet of the condenser C3 (90). One end of the side branch pipe is connected between the scale filter (140) and the second switch valve. A third switch valve is installed on the side branch pipe. A second side branch pipe is led out between the first switch valve and the cold side inlet of the condenser C2 (80). One end of the second side branch pipe is connected between the second switch valve and the cold side outlet of the condenser C2 (80). A fourth switch valve is installed on the second side branch pipe.

4. A high-temperature heat pump steam unit system based on petrochemical waste heat according to claim 3, characterized in that, The condenser C2 (80) is equipped with a five-way valve on the hot side inlet and a six-way valve on the hot side outlet. A side branch pipe three is led out between the gas phase outlet side of the switching valve five and the two-phase separator S1 (100). One end of the side branch pipe three is connected between the switching valve six and the two-phase inlet of the two-phase separator S2 (110). A switching valve seven is installed on the side branch pipe three. A side branch pipe four is led out between the hot side outlet of the switch valve six and the condenser C2 (80). One end of the side branch pipe four is connected between the switch valve five and the gas phase outlet of the two-phase separator S1 (100). A switch valve eight is installed on the side branch pipe four.

5. A high-temperature heat pump steam unit system based on petrochemical waste heat according to claim 2, characterized in that, The condenser C2 (80) includes a shell (81) and a tube-side inner wall cleaning component (82). The shell (81) is provided with a working fluid inlet, a working fluid outlet, a water inlet, and a water outlet. The water inlet and the water outlet are distributed at both ends of the shell (81). Both ends of the shell (81) are provided with partition plates (83). The two sets of partition plates (83) are provided with corresponding holes for welding and installing cold side pipes (84). The working fluid inlet is distributed on the upper side of one end of the shell (81), and the working fluid outlet is distributed on the lower side of the end of the shell (81) away from the working fluid inlet. A spiral guide plate (85) is installed inside the housing (81). Several through holes are evenly distributed on the spiral guide plate (85). The cold side pipe (84) passes through the corresponding through holes. The pipe side inner wall cleaning component (82) is installed at the end of the cold side pipe (84). The pipe side inner wall cleaning component (82) has a structure for cleaning the dirt on the inner wall of the cold side pipe (84).

6. A high-temperature heat pump steam unit system based on petrochemical waste heat according to claim 5, characterized in that, The inner wall cleaning component (82) of the pipe includes an installation body (841) installed at both ends of the cold side pipe (84) and a cleaning body (842) movably distributed within the installation body (841). An interceptor is provided at the end of the installation body (841) away from the cold side pipe (84). Multiple side openings (843) are distributed circumferentially on the installation body (841). The opening size of the side openings (843) is smaller than the size of the cleaning body (842).

7. A high-temperature heat pump steam unit system based on petrochemical waste heat according to claim 6, characterized in that, The cleaning body (842) includes an intermediate sleeve (846) and a brush body (847) spirally distributed on the outside of the intermediate sleeve (846). Conical covers (844) are distributed at both ends of the intermediate sleeve (846). A deformable cover (845) is provided at the end of the conical cover (844) away from the intermediate sleeve (846). An elastic pin is installed on the conical cover (844). A follower rod (848) is movably installed inside the intermediate sleeve (846). The two ends of the follower rod (848) are respectively connected to the inner walls of the two sets of deformable covers (845). A constraint ring groove (849) adapted to the elastic pin is provided on the follower rod (848). An extrusion member (8410) is installed at the end of the interceptor facing the deformable shield (845).

8. A high-temperature heat pump steam unit system based on petrochemical waste heat according to claim 1, characterized in that, The evaporators E1 (30) and E2 (40) are plate heat exchangers or shell-and-tube heat exchangers, and the heat exchange area of ​​evaporator E1 (30) is greater than that of evaporator E2 (40).

9. A control method for a high-temperature heat pump steam unit system based on petrochemical waste heat according to claim 4, characterized in that, The steps are as follows: Step 1, Waste Heat Recovery Stage: Petrochemical waste hot water at 80-90℃ flows sequentially through evaporator E1 (30) and evaporator E2 (40). After heat exchange on the hot side of evaporator E1 (30), the temperature drops to 65-70℃. After heat exchange on the hot side of evaporator E2 (40), the temperature drops to 40-50℃ and is then discharged. The working fluid absorbs heat from 55-60°C to 60-65°C on the cold side of evaporator E1 (30), and absorbs heat from 35-40°C to 40-45°C on the cold side of evaporator E2 (40). The two working fluids merge at the outlet and reach a temperature of 55-60°C before entering the cold side of regenerator (130). Step 2, Reheating and Overheating Stage: The combined 55-60℃ mixed gas absorbs heat from the hot side liquid in the cold side of the regenerator (130), and enters the compressor (120) after being heated by 5-15℃. Step 3, Compression Stage: The compressor (120) compresses the mixed gas to a high temperature and high pressure state, and the exhaust temperature reaches 140-160℃, which is then discharged into the hot side of the condenser C1 (70). Step 4, Staged condensation and steam generation: A high-temperature and high-pressure mixed working fluid of 140-160℃ flows sequentially through the hot side of condenser C1 (70), condenser C2 (80) and condenser C3 (90), and releases heat through staged condensation. Among them, the hot side of condenser C1 (70) cools down from 140-160℃ to 125-135℃, the hot side of condenser C2 (80) cools down from 125-135℃ to 100-110℃, and the hot side of condenser C3 (90) cools down from 100-110℃ to 75-85℃. The makeup water at 20-30℃ flows sequentially through the cold side of condenser C3 (90), condenser C2 (80) and condenser C1 (70), and is heated in stages. The cold side outlet water temperature of condenser C3 (90) is 50-65℃, the cold side outlet water temperature of condenser C2 (80) is 80-90℃, and the cold side outlet of condenser C1 (70) generates saturated steam at 120-130℃, which is output through steam pipe (60). Step 5: Component separation and reheating / subcooling stage: The 125-135℃ high-boiling-point liquid phase separated in the two-phase separator S1 (100) enters the hot side of the regenerator (130), releases heat and cools down to 80-90℃, then passes through the throttle valve to reduce pressure and temperature to 55-60℃, and flows back to the cold side inlet of the evaporator E1 (30). The 100-110℃ rich medium boiling point liquid phase separated in the two-phase separator S2 (110) is mixed with the 75-85℃ rich low boiling point liquid phase at the outlet of the condenser C3 (90). After mixing, the temperature of the mixture is 85-95℃. The mixture is then depressurized and cooled to 35-40℃ through the second throttle valve and enters the cold side inlet of the evaporator E2 (40). The working fluid absorbs heat in evaporators E1 (30) and E2 (40) respectively, and after merging at the outlet, it enters the cold side of the regenerator (130) to complete the cycle; Step 6, Tube cleaning: The state switches between state one and state two every 2-4 hours. State 1: Switch valves 7 and 8 are closed, and switch valves 5 and 6 are open. The medium and low boiling point gas phase mixed working fluid enters the hot side of the condenser C2 (80) through switch valve 5 to release heat, and enters the two-phase separator S2 (110) through switch valve 6. Switch valves three and four are in the closed state, and switch valves one and two are in the open state. Water heated by condenser C3 (90) enters the cold side of condenser C2 (80) through switch valve one to absorb heat, and enters the scale filter (140) through switch valve two. State Two: Switch valves five and six are in the closed state, and switch valves seven and eight are in the open state. The medium and low boiling point gas phase mixed working fluid enters the hot side of the condenser C2 (80) through switch valve seven to release heat, and enters the two-phase separator S2 (110) through switch valve eight. Switch valve 1 and switch valve 2 are in the closed state, and switch valve 3 and switch valve 4 are in the open state. Water heated by condenser C3 (90) enters the cold side of condenser C2 (80) through switch valve 3 to absorb heat, and enters the scale filter (140) through switch valve 4.

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