A hot water return heating system

Abstract

The utility model belongs to heating device technical field relates to a hot water return water heating system, including hot water return water pipeline, fraction oil heater, pressure reducing tower, fraction oil collection jar and hot water supply pipeline, the hot water return water pipeline is communicated with hot water supply pipeline through fraction oil heater, the top of pressure reducing tower is divided into two ways, one way directly communicates with fraction oil collection jar, another way communicates with fraction oil collection jar again after fraction oil heater. The utility model uses the fraction oil of pressure reducing tower top as heating medium to heat hot water return water, avoids using steam heating, improves system safety, saves steam resources, reduces production cost, realizes effective recovery of fraction oil of pressure reducing tower top simultaneously.

Description

Technical Field

[0001] This utility model belongs to the technical field of heating devices and relates to a hot water return heating system for heating the heat transfer medium of a heat tracing pipeline. Background Technology

[0002] In the production process of producing naphthenic oils from coal tar hydrogenation, heat tracing pipelines are often installed in the process pipelines to heat them and ensure stable and normal production operation. Hot water is primarily used as the heat transfer medium in these pipelines. The hot water enters from the inlet and transfers its heat to the production materials in the process pipeline as it flows towards the outlet. Finally, the heat-exchanged hot water exits from the outlet. In actual operation, to save hot water consumption, the heat-exchanged hot water is returned to the hot water inlet as return water for circulating heat tracing. However, the temperature of the hot water decreases after heat transfer, and continuous circulation is insufficient to meet the heating requirements of the process pipelines, leading to unstable production operation. Therefore, it is necessary to reheat the hot water return water before returning it to the hot water inlet.

[0003] Currently, a steam heater is installed between the hot water return and hot water inlet, using steam from the production system as the heating medium to heat the hot water return, which then forms condensate after heat exchange. However, during winter operation, the condensate return pressure abnormally increases, reaching a maximum of 0.45 MPa. This presents the following problems:

[0004] (1) Poor system safety: The high return pressure of condensate water causes the medium in the pipeline to be unable to flow normally, which in turn freezes in the low temperature environment. This not only affects the normal operation of production, but also damages the equipment and increases the risk of maintenance.

[0005] (2) Steam tracing also leads to the waste of steam resources: In the steam tracing system, steam will condense into steam and condensate after heating the pipeline, and then be sent out of the device after being cooled by circulating water. This not only increases the consumption of steam, but also increases the production cost. Utility Model Content

[0006] To address the technical problems of poor system safety and waste of steam resources in existing heat tracing systems that utilize steam heating, this utility model proposes a hot water return heating system.

[0007] This invention uses a distillate oil heater and a vacuum tower to heat hot water return water by using the distillate oil at the top of the vacuum tower as a heating medium, avoiding the use of steam heating, improving system safety, saving steam resources, reducing production costs, and simultaneously achieving effective recovery of the distillate oil at the top of the vacuum tower.

[0008] In order to achieve the above objectives, the purpose of this utility model is:

[0009] A hot water return heating system includes a hot water return pipeline, a distillate oil heater, a pressure reducing tower, a distillate oil collection tank, and a hot water supply pipeline;

[0010] The hot water return pipeline is connected to the hot water supply pipeline via the distillate oil heater; the top of the pressure reducing tower is divided into two paths, one of which is directly connected to the distillate oil collection tank, and the other is connected to the distillate oil collection tank via the distillate oil heater.

[0011] Furthermore, the hot water return heating system also includes a delivery pump disposed between the hot water return pipeline and the distillate oil heater.

[0012] Further specified, a first control valve for the distillate oil heater is provided between the delivery pump and the distillate oil heater; a second control valve for the distillate oil heater is provided between the distillate oil heater and the hot water supply pipeline.

[0013] Further specified, a first control valve for the pressure reducing tower and a third control valve for the distillate oil heater are sequentially installed between the top of the pressure reducing tower and the distillate oil heater; a fourth control valve for the distillate oil heater is installed between the distillate oil heater and the distillate oil collection tank; and a second control valve for the pressure reducing tower is installed between the top of the pressure reducing tower and the distillate oil collection tank.

[0014] Furthermore, a temperature instrument is installed between the distillate oil heater and the second control valve of the distillate oil heater.

[0015] Furthermore, the hot water return heating system also includes a pressure gauge, a temperature gauge, and a safety valve sequentially installed on the hot water return pipeline; the safety valve is located near the delivery pump.

[0016] Further specifying, the hot water return heating system also includes an air cooler, the second control valve of the pressure reducing tower is connected to the distillate oil collection tank via the air cooler; the fourth control valve of the distillate oil heater is connected to the distillate oil collection tank via the air cooler; and the air cooler is also connected to the tower side of the pressure reducing tower.

[0017] Furthermore, the hot water return heating system also includes a demineralized water pipeline; the demineralized water pipeline is connected to the hot water return pipeline, and the connection point of the demineralized water pipeline is located between the temperature instrument and the safety valve.

[0018] Further specifying, a demineralized water control valve and a demineralized water check valve are sequentially installed on the demineralized water pipeline, with the demineralized water check valve located near the hot water return pipeline.

[0019] Further specifying, the hot water return heating system also includes a steam heater, a steam heater pre-control valve, and a steam heater post-control valve; one end of the steam heater is connected to the delivery pump via the steam heater pre-control valve, and the other end of the steam heater is connected to the hot water supply pipeline via the steam heater post-control valve.

[0020] Compared with the prior art, the technical effects of this utility model are:

[0021] 1. This utility model is equipped with a distillate oil heater and a vacuum tower. The distillate oil at the top of the vacuum tower is used as a heating medium to heat the hot water return water, thereby avoiding the generation of condensate water by steam heating. Since no condensate water is generated in the entire heat tracing system, the system safety is improved, steam resources are saved, and production costs are reduced. At the same time, the temperature of the distillate oil decreases after heating the hot water, completing the cooling and realizing the effective recovery of the distillate oil at the top of the vacuum tower.

[0022] 2. This utility model installs a pressure gauge, a temperature gauge, and a safety valve sequentially on the hot water return pipeline. The temperature and pressure of the hot water returning into the hot water return pipeline through the pressure gauge and temperature gauge layers provide data support for system operation. On the other hand, when the pressure is too high, the safety valve is opened to release the pressure, ensuring the safe and stable operation of the system.

[0023] 3. This utility model provides an air cooler between the top of the vacuum distillation tower and the distillate oil collection tank; the air cooler further cools the cooled distillate oil at the top of the vacuum distillation tower, ensuring that the temperature of the distillate oil at the top of the tower meets the recovery requirements.

[0024] 4. This utility model sets up a steam heater as a backup to ensure stable system operation; at the same time, by combining the flexible control of the steam heater front control valve, the steam heater rear control valve, the first control valve of the distillate oil heater, and the second control valve of the distillate oil heater, the switching between the steam heater and the distillate oil heater can be realized. Under normal circumstances, the distillate oil heater works to heat the hot water; when the pressure reducing tower unit is shut down or the supply of distillate oil at the top of the tower is insufficient, the steam heater is switched as a backup by controlling the various valves to ensure the normal operation of the hot water return heating system.

[0025] 5. This utility model is equipped with a first control valve for the pressure reducing tower, a second control valve for the pressure reducing tower, a third control valve for the distillate oil heater, and a fourth control valve for the distillate oil heater. On the one hand, it controls the flow direction of the distillate oil generated at the top of the pressure reducing tower (as a heating medium and product oil); on the other hand, it controls the flow rate of the distillate oil entering the distillate oil heater by combining the temperature data of the temperature instrument installed between the other end of the distillate oil heater and the second control valve of the distillate oil heater. When the temperature is lower than the hot water inlet temperature, the flow rate of the distillate oil entering the distillate oil heater is increased; conversely, the flow rate of the distillate oil entering the distillate oil heater is decreased. This not only makes operation convenient but also fully ensures the heat recovery of the distillate oil and ensures stable operation. Attached Figure Description

[0026] Figure 1 A schematic diagram of the first type of hot water return heating system provided by this utility model;

[0027] Figure 2 A schematic diagram of the second type of hot water return heating system provided by this utility model;

[0028] in:

[0029] 10-Hot water return pipeline; 20-Steam heater; 30-Distillate oil heater; 40-Pressure reducing tower; 50-Air cooler; 60-Distillate oil collection tank; 70-Hot water supply pipeline; 80-Demineralized water pipeline; 90-Safety valve;

[0030] P101 - First transfer pump; F101 - Control valve before the first transfer pump; F102 - Control valve after the first transfer pump;

[0031] P102 - Second transfer pump; F103 - Control valve before the second transfer pump; F104 - Control valve after the second transfer pump;

[0032] F201 - Control valve before steam heater; F202 - Control valve after steam heater;

[0033] F301 - First control valve for distillate oil heater; F302 - Second control valve for distillate oil heater; F303 - Third control valve for distillate oil heater; F304 - Fourth control valve for distillate oil heater;

[0034] F401 - First control valve of pressure reducing tower; F402 - Second control valve of pressure reducing tower; F403 - Third control valve of pressure reducing tower; F801 - Demineralized water control valve; F802 - Demineralized water check valve. Detailed Implementation

[0035] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0036] See Figure 1 This utility model provides a hot water return heating system, including a hot water return pipeline 10, a distillate oil heater 30, a pressure reducing tower 40, a distillate oil collection tank 60, and a hot water supply pipeline 70; the hot water return pipeline 10 is connected to the hot water supply pipeline 70 via the distillate oil heater 30; the top of the pressure reducing tower 40 is divided into two paths, one of which is directly connected to the distillate oil collection tank 60, and the other of which is connected to the distillate oil collection tank 60 after passing through the distillate oil heater 30.

[0037] In use, the heat tracing pipeline is installed on the process pipeline. The output end of the hot water supply pipeline 70 is used to provide heat medium to the heat tracing pipeline for heat tracing. After the heat medium is cooled, it enters the hot water return pipeline 10 and then enters the distillate oil heater 30. At the same time, the distillate oil (temperature 159-280℃) discharged from the top of the pressure reducing tower 40 also enters the distillate oil heater 30. After cooling, the heat medium and the distillate oil exchange heat in the distillate oil heater 30. After cooling, the heat medium is reheated, and the distillate oil is cooled. The reheated heat medium re-enters the hot water supply pipeline 70 through the hot water supply pipeline 70 to achieve circulating heat tracing. After the distillate oil is cooled, it enters the distillate oil collection tank 60 for collection. This utility model uses the distillate oil produced by the coal tar hydrogenation to cycloalkyl oil process to reheat the hot water return water. On the one hand, it avoids the problems of poor system safety and waste of steam resources caused by steam heating, improves system safety and saves steam resources. On the other hand, it makes full use of the heat of the distillate oil and avoids heat waste.

[0038] In one possible embodiment of this utility model, the hot water return heating system further includes a delivery pump disposed between the hot water return pipeline 10 and the distillate oil heater 30. The delivery pump provides power to drive the hot water return to flow into the distillate oil heater 30.

[0039] See Figure 1Preferably, the transfer pump includes a first transfer pump P101, one end of which is connected to the hot water return pipeline 10, and the other end of which is connected to one end of the distillate oil heater 30. In practice, a first transfer pump pre-control valve F101 is installed at the front end of the first transfer pump P101, and a first transfer pump post-control valve F102 is installed at the rear end of the first transfer pump P101. To facilitate the installation and connection of the transfer pump and valves, a first branch is set up. The first transfer pump pre-control valve F101, the first transfer pump P101, and the first transfer pump post-control valve F102 are sequentially installed on the first branch. One end of the first branch is connected to the hot water return pipeline 10, and the other end of the first branch is connected to the distillate oil heater 30. Thus, the hot water return sequentially passes through the first transfer pump pre-control valve F101, the first transfer pump P101, and the first transfer pump post-control valve F102 before connecting to the distillate oil heater 30.

[0040] To improve operational stability, a backup transfer pump, namely the second transfer pump P102, is provided. A second transfer pump pre-control valve F103 is installed at the front end of the second transfer pump P102, and a second transfer pump post-control valve F104 is installed at the rear end of the second transfer pump P102. Similarly, a second branch is provided in parallel with the first branch. The second transfer pump pre-control valve F103, the second transfer pump P102, and the second transfer pump post-control valve F104 are sequentially installed on the second branch. The installation and connection of the second branch and the equipment thereon are the same as those of the first branch and its equipment. In use, the second transfer pump P102 on the second branch serves as a backup and is activated when the first transfer pump P101 on the first branch fails. Switching between the two transfer pumps is achieved through the valves on the first and second branches.

[0041] In one possible embodiment of this utility model, a first control valve F301 for the distillate oil heater is installed between the delivery pump and the distillate oil heater 30; a second control valve F302 for the distillate oil heater is installed between the distillate oil heater 30 and the hot water supply pipeline 70. A first control valve F401 and a third control valve F303 for the distillate oil heater are installed sequentially between the top of the pressure reducing tower 40 and the distillate oil heater 30; a fourth control valve F304 for the distillate oil heater is installed between the distillate oil heater 30 and the distillate oil collection tank 60; and a second control valve F402 for the pressure reducing tower is installed between the top of the pressure reducing tower 40 and the distillate oil collection tank 60.

[0042] Preferably, when the delivery pump includes a first delivery pump P101 and a second delivery pump P102, the output ends of both delivery pumps are connected to the distillate oil heater 30, realizing a standby operation mode.

[0043] The performance parameters of the two transfer pumps are as follows: flow rate is 105 m³ / h. 3 / h, head not less than 50m, inlet pressure of 0.3MPa(g) of the delivery pump, able to overcome the total resistance of the external pipeline network of 0.35MPa, and ensure the normal operation of the water pump.

[0044] Preferably, the distillate oil heater 30 has a shell-and-tube structure, with the distillate oil inlet and outlet connected to the shell side, and the hot water inlet and outlet connected to the tube side. The hot water return water to be heated flows in the tube side, while the distillate oil to be cooled flows in the shell side. During material flow, the distillate oil heats the hot water return water for recycling, and the heated distillate oil is collected directly after its temperature decreases. Preferably, the hot water return water and distillate oil flow in opposite directions to improve heat exchange efficiency.

[0045] Preferably, the distillate oil heater 30 is provided with a distillate oil inlet, a distillate oil outlet, a hot water inlet, and a hot water outlet; the distillate oil inlet and outlet are located on opposite sides of the distillate oil heater 30, the hot water inlet and outlet are located on opposite sides of the distillate oil heater 30, and the distillate oil inlet and outlet are located on the same side of the distillate oil heater 30. The top of the vacuum tower 40 is connected to the distillate oil inlet, the distillate oil outlet, and the distillate oil collection tank 60, and the delivery pump is connected to the hot water inlet, the hot water outlet, and the hot water supply pipeline 70. The top of the pressure reducing tower 40 is connected to the distillate oil inlet via the first control valve F401 and the third control valve F303 of the distillate oil heater. The distillate oil outlet is connected to the distillate oil collection tank 60 via the fourth control valve F304 of the distillate oil heater. The delivery pump is connected to the hot water inlet via the first control valve F301 of the distillate oil heater. The hot water outlet is connected to the hot water supply pipeline 70 via the second control valve F302 of the distillate oil heater.

[0046] In one possible embodiment of this utility model, a temperature instrument is installed between the distillate oil heater 30 and the second control valve F302 of the distillate oil heater. The temperature instrument monitors the temperature of the hot water exiting the distillate oil heater 30 to ensure that the temperature of the hot water entering the heat tracing pipeline (generally at 90°C) meets the requirements for heat tracing the process pipeline.

[0047] In one possible embodiment of this utility model, the hot water return heating system further includes a pressure gauge, a temperature gauge, and a safety valve 90 sequentially arranged on the hot water return pipeline 10; the safety valve 90 is located at the front end of the delivery pump. It is used to monitor the temperature and pressure of the heat medium entering the hot water return pipeline 10, providing operating data for the system.

[0048] In one possible embodiment of this utility model, the hot water return heating system further includes an air cooler 50. The second control valve F402 of the pressure reducing tower is connected to the distillate oil collection tank 60 via the air cooler 50; the fourth control valve F304 of the distillate oil heater is connected to the distillate oil collection tank 60 via the air cooler 50; the air cooler 50 is also connected to the side of the pressure reducing tower 40. In use, through the first control valve F401 and the second control valve F402 of the pressure reducing tower, most of the distillate oil produced at the top of the pressure reducing tower 40 enters the distillate oil heater 30, while a small portion of the distillate oil directly enters the air cooler 50. After the majority of the distillate oil entering the distillate oil heater 30 is heated by the heat medium, the heat exchange temperature of the distillate oil decreases. The cooled distillate oil then enters the air cooler 50 for secondary cooling; the small portion of the distillate oil that directly enters the air cooler 50 is further cooled. The distillate oil (temperature 159-280℃) produced at the top of the vacuum distillation tower 40 is cooled by air cooler 50 until the temperature drops to 40℃. Then it enters the distillate oil collection tank 60 for collection and recovery to obtain product oil for sale.

[0049] In implementation, since most of the distillate oil produced at the top of the vacuum distillation tower 40 enters the distillate oil heater 30 to heat the hot water, to prevent the distillate oil from being unable to enter the heater 30 in case of an emergency shutdown, a bypass pipe is connected between the first control valve F401 of the vacuum distillation tower and the third control valve F303 of the distillate oil heater. The other end of the bypass pipe is directly connected to the air cooler 50. Simultaneously, for ease of control, the third control valve F403 of the vacuum distillation tower is installed on the bypass pipe. During normal operation of the distillate oil heater 30, the third control valve F403 of the vacuum distillation tower is closed, while the third control valve F303 and the fourth control valve F304 of the distillate oil heater are open, allowing the distillate oil to enter the heater 30 to heat the hot water return. In case of an emergency, the third control valve F403 of the vacuum distillation tower opens, while the third control valve F303 and the fourth control valve F304 of the distillate oil heater close, allowing the distillate oil to directly enter the air cooler 50 for cooling and recovery of the distillate product oil.

[0050] In one possible embodiment of this utility model, the hot water return heating system further includes a demineralized water pipeline 80; the demineralized water pipeline 80 is connected to the hot water return pipeline 10, and the connection position of the demineralized water pipeline 80 is located between the temperature instrument and the safety valve 90.

[0051] A demineralized water control valve F801 and a demineralized water check valve F802 are installed sequentially on the demineralized water pipeline 80, with the demineralized water check valve F802 located near the hot water return pipeline 10.

[0052] In this invention, the purpose of the demineralized water pipeline 80 is to replenish demineralized water to the system when the pressure of the hot water return is insufficient (e.g., below 0.4 MPa). The pressure of the demineralized water is 0.6 MPa.

[0053] In one possible embodiment of this utility model, a demineralized water control valve F801 and a demineralized water check valve F802 are sequentially installed on the demineralized water pipeline 80, with the demineralized water check valve F802 located closer to the hot water return pipeline 10. During use, when demineralized water needs to be added to the system, the demineralized water control valve F801 and the demineralized water check valve F802 are opened for replenishment. The demineralized water check valve F802 can only be opened to the hot water return pipeline 10, preventing hot water in the hot water return pipeline 10 from flowing back into the demineralized water pipeline 80.

[0054] See Figure 2 In one possible embodiment of this utility model, the hot water return heating system further includes a steam heater 20, a steam heater pre-control valve F201, and a steam heater post-control valve F202. One end of the steam heater 20 is connected to a delivery pump via the steam heater pre-control valve F201, and the other end of the steam heater 20 is connected to the hot water supply pipeline 70 via the steam heater post-control valve F202. In this embodiment, the steam heater 20 and the distillate oil heater 30 are connected in parallel to form a standby configuration. When the distillate oil heater 30 malfunctions or the pressure reducing tower 40 stops operating, the steam heater 20 is activated to heat the heat medium in the hot water return pipeline 10. The heat source for the steam heater 20 is provided by low-pressure steam (0.5 MPa) from the steam network; the operation of the steam heater 20 is controlled by the steam heater pre-control valve F201 and the steam heater post-control valve F202.

[0055] It should be noted that the control and switching of each valve in this invention can be either manual or automatic. Preferably, it is automatic control, for example, by connecting each valve to a DCS control system, where the DCS controls the opening and closing of the valves based on collected data such as temperature and pressure. The connection of each valve and the DCS's control and switching of the valves both employ conventional techniques in the field and will not be described in detail here.

[0056] The temperature and pressure monitoring and control in each reaction device of this invention are all known technologies in chemical production, and will not be described in detail here.

[0057] This invention uses distillate oil from a vacuum distillation tower to heat hot water return water, raising its temperature and circulating it to heat the process pipelines. This more effectively maintains the temperature stability of the process pipelines and heat tracing pipelines, ensuring the continuity and safety of the production process, reducing production interruptions caused by equipment failures, and further improving the company's production efficiency. At the same time, it makes full use of the heat energy wasted by the original cooling of the distillate oil, realizing the recovery of distillate oil products, and achieving the goal of energy saving, cost reduction and efficiency improvement.

[0058] Obviously, the embodiments described above are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

Claims

1. A hot water return heating system, characterized in that, It includes a hot water return pipeline (10), a distillate oil heater (30), a pressure reducing tower (40), a distillate oil collection tank (60), and a hot water supply pipeline (70); The hot water return pipeline (10) is connected to the hot water supply pipeline (70) via the distillate oil heater (30); the top of the pressure reducing tower (40) is divided into two paths, one of which is directly connected to the distillate oil collection tank (60), and the other is connected to the distillate oil collection tank (60) via the distillate oil heater (30).

2. The hot water return heating system according to claim 1, characterized in that, The hot water return heating system also includes a delivery pump located between the hot water return pipeline (10) and the distillate oil heater (30).

3. The hot water return heating system according to claim 2, characterized in that, A first control valve (F301) for the distillate oil heater is provided between the delivery pump and the distillate oil heater (30); a second control valve (F302) for the distillate oil heater is provided between the distillate oil heater (30) and the hot water supply pipeline (70).

4. The hot water return heating system according to claim 3, characterized in that, A first control valve (F401) and a third control valve (F303) for the distillate oil heater are sequentially installed between the top of the pressure reducing tower (40) and the distillate oil heater (30); a fourth control valve (F304) for the distillate oil heater is installed between the distillate oil heater (30) and the distillate oil collection tank (60); and a second control valve (F402) for the pressure reducing tower is installed between the top of the pressure reducing tower (40) and the distillate oil collection tank (60).

5. The hot water return heating system according to claim 4, characterized in that, A temperature instrument is installed between the distillate oil heater (30) and the second control valve (F302) of the distillate oil heater.

6. The hot water return heating system according to claim 5, characterized in that, The hot water return heating system also includes a pressure gauge, a temperature gauge and a safety valve (90) arranged sequentially on the hot water return pipeline (10); the safety valve (90) is located near the delivery pump.

7. The hot water return heating system according to claim 4, characterized in that, The hot water return heating system also includes an air cooler (50), the second control valve (F402) of the pressure reducing tower is connected to the distillate oil collection tank (60) via the air cooler (50); the fourth control valve (F304) of the distillate oil heater is connected to the distillate oil collection tank (60) via the air cooler (50); the air cooler (50) is also connected to the tower side of the pressure reducing tower (40).

8. The hot water return heating system according to claim 6, characterized in that, The hot water return heating system also includes a demineralized water pipeline (80); the demineralized water pipeline (80) is connected to the hot water return pipeline (10), and the connection point of the demineralized water pipeline (80) is located between the temperature instrument and the safety valve (90).

9. The hot water return heating system according to claim 8, characterized in that, The demineralized water pipeline (80) is sequentially equipped with a demineralized water control valve (F801) and a demineralized water check valve (F802), with the demineralized water check valve (F802) located near the hot water return pipeline (10).

10. The hot water return heating system according to claim 4, characterized in that, The hot water return heating system also includes a steam heater (20), a steam heater front control valve (F201), and a steam heater rear control valve (F202); one end of the steam heater (20) is connected to the delivery pump via the steam heater front control valve (F201), and the other end of the steam heater (20) is connected to the hot water supply pipeline (70) via the steam heater rear control valve (F202).

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