Steam condensate waste heat recovery device

Abstract

The utility model relates to the field of steam condensate treatment, and discloses a steam condensate waste heat recovery device. The device comprises a steam condensate heater, a steam condensate buffer tank and a downstream application device heater, an inlet of the steam condensate heater is communicated with a steam condensate feeding pipeline; an outlet of the steam condensate heater is communicated with an inlet of the steam condensate buffer tank; an outlet of the steam condensate buffer tank is communicated with a steam condensate inlet of a downstream application device heater; and a steam condensate outlet of the downstream application device heater is communicated with a steam condensate feeding pipeline. By adopting the device disclosed by the utility model, the waste heat of the steam condensate can be maximally and stably utilized.

Description

Technical Field

[0001] This utility model relates to the field of steam condensate treatment, specifically to a steam condensate waste heat recovery device. Background Technology

[0002] Steam condensate is treated in chemical plants in several ways: first, it is recycled and treated before being reused in the boiler; second, it is used as demineralized water; and third, it is used as makeup water for the circulating water system. Because steam condensate can become contaminated with mechanical impurities such as rust or due to material leaks during use, it requires a complex treatment process before it can be reused as boiler water. It can only be used directly as demineralized water under special circumstances. Therefore, steam condensate is more often used as makeup water for the circulating water system. However, it needs to be cooled before use as makeup water, which not only wastes a lot of heat but also consumes a large amount of circulating water, further increasing energy consumption.

[0003] CN101251248A discloses a method for improving the heat exchange / tracing of a steam system in a bisphenol A (BPA) unit. This method involves adding a flash tank to the low-pressure steam system to flash-evaporate the collected medium-pressure steam condensate and supplying the flash-evaporated steam to the low-pressure steam main. This method can recover some of the waste heat from the higher-temperature steam condensate, but it cannot further recover heat from the lower-temperature steam condensate.

[0004] Therefore, how to make full use of the waste heat of steam condensate is a problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] The purpose of this invention is to overcome the problems existing in the prior art and provide a steam condensate waste heat recovery device. Using the device described in this invention, the waste heat of steam condensate can be utilized to the maximum extent and stably.

[0006] To achieve the above objectives, this utility model provides a steam condensate waste heat recovery device, which includes a steam condensate heater, a steam condensate buffer tank, and a downstream application device heater.

[0007] The inlet of the steam condensate heater is connected to the steam condensate feed pipeline;

[0008] The outlet of the steam condensate heater is connected to the inlet of the steam condensate buffer tank.

[0009] The outlet of the steam condensate buffer tank is connected to the steam condensate inlet of the heater in the downstream application device.

[0010] The steam condensate outlet of the heater in the downstream application device is connected to the steam condensate feed pipeline.

[0011] The beneficial effects of this utility model through the above technical solution include:

[0012] The device described in this invention can maximize and stably utilize the waste heat of steam condensate, effectively improving energy utilization efficiency. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the device provided by this utility model.

[0014] Explanation of reference numerals in the attached figures

[0015] 1. Steam condensate heater; 2. Steam condensate buffer tank; 3. Steam condensate circulation pump;

[0016] 4. Downstream application device heater. Detailed Implementation

[0017] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0018] This utility model provides a steam condensate waste heat recovery device, which includes a steam condensate heater 1, a steam condensate buffer tank 2, and a downstream application device heater 4.

[0019] The inlet of the steam condensate heater 1 is connected to the steam condensate feed pipeline;

[0020] The outlet of the steam condensate heater 1 is connected to the inlet of the steam condensate buffer tank 2;

[0021] The outlet of the steam condensate buffer tank 2 is connected to the steam condensate inlet of the downstream application device heater 4.

[0022] The steam condensate outlet of the downstream application device heater 4 is connected to the steam condensate feed pipeline.

[0023] The device provided by this utility model has the ability to adjust to various fluctuations in the operating conditions of the device (fluctuations in the feed temperature and feed rate of steam condensate, etc.), and can solve the stability problem in the use of steam condensate.

[0024] In this field, the lower the temperature of steam condensate, the more difficult it is to recover heat. The device provided by this invention can handle both high-temperature and low-temperature steam condensate. In this invention, when the temperature of the steam condensate feed is lower than the temperature required by the downstream application device heater 4, or when the pressure of the buffer tank is lower than its predetermined pressure, the steam condensate heater 1 is turned on for heating, and then the condensate is sent to the steam condensate buffer tank 2 for buffering.

[0025] In this invention, when the flow rate of the steam condensate feed is less than the flow rate required by the downstream application device heater 4, the following steam condensate circulation pipeline is opened to reuse the heat-exchanged steam condensate flowing out of the steam condensate outlet of the downstream application device heater 4.

[0026] According to this invention, the steam condensate outlet of the downstream application device heater 4 is connected to the steam condensate feed pipeline. This implementation ensures that the steam condensate waste heat recovery device can operate stably for extended periods.

[0027] According to a preferred embodiment of the present invention, a steam mixing point is provided on the steam condensate feed pipeline.

[0028] According to a preferred embodiment of this invention, the steam condensate outlet of the downstream application device heater 4 is connected to the steam mixing point of the steam condensate feed pipeline. This preferred embodiment facilitates accurate control of the steam condensate feed temperature.

[0029] In this invention, the specific location of the mixing point can be adjusted appropriately according to the actual situation in order to more accurately control the feed temperature.

[0030] According to a preferred embodiment of the present invention, the distance between the steam mixing point and the steam condensate heater 1 is 10-90% of the length of the steam condensate feed pipeline, specifically 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and any range of any two of these points.

[0031] According to a more preferred embodiment of the present invention, the distance between the steam mixing point and the steam condensate heater 1 is 20-80% of the length of the steam condensate feed pipeline.

[0032] According to a preferred embodiment of the present invention, a steam condensate circulation pipeline is provided at the steam condensate outlet of the downstream application device heater 4.

[0033] According to a preferred embodiment of the present invention, a water outlet pipeline is also provided at the steam condensate outlet of the downstream application device heater 4.

[0034] In this preferred embodiment, the condensate from the heat exchanged steam is partially reused through a steam condensate circulation pipeline, while the remaining portion is discharged from the device through an outlet pipeline.

[0035] According to a preferred embodiment of the present invention, the steam condensate outlet of the downstream application device heater 4 is connected to the steam mixing point through a steam condensate circulation pipeline.

[0036] This invention allows for a wide range of choices for the type of heater 4 in the downstream application device. Generally, it requires that the heat transfer temperature difference between the steam condensate feed and the heater 4 in the downstream application device be no less than 5°C. For example, it can be a toluene oxime pre-separation tower reboiler, a deammonia removal tower reboiler, etc.

[0037] The downstream application device heater 4 described in this utility model can be one or more, and can be appropriately selected according to the actual application.

[0038] According to a preferred embodiment of the present invention, the device further includes a steam condensate circulation pump 3 for conveying the effluent from the steam condensate buffer tank 2 to the downstream application device heater 4.

[0039] According to a preferred embodiment of the present invention, the steam condensate circulating pump 3 is disposed between the steam condensate buffer tank 2 and the downstream application device heater 4.

[0040] The present invention will be described in detail below through embodiments.

[0041] Example 1

[0042] This embodiment provides a process for separating toluene and cyclohexanone oxime in a caprolactam ammonium oxime unit using waste heat from steam condensate. This process can be referred to... Figure 1 .

[0043] Steam condensate at 140°C and 0.5MPaG from the steam condensate pipeline is fed into the steam condensate buffer tank 2 via the steam condensate feed pipeline and the steam condensate heater 1. The operating conditions of the steam condensate buffer tank 2 include: temperature of 140°C and pressure of 0.26MPaG.

[0044] After buffering, the steam condensate is pressurized to 0.6 MPaG by the steam condensate circulation pump 3 and then connected to the hot side inlet of the reboiler of the toluene-oxime pre-separation tower. A steam condensate circulation pipeline and a water outlet pipeline are provided at the hot side outlet of the reboiler. The steam mixing point of the reboiler hot side outlet and the steam condensate feed pipeline (the distance between the steam mixing point and the steam condensate heater 1 is 30% of the length of the steam condensate feed pipeline) is connected through the steam condensate circulation pipeline. The steam condensate after heat exchange at the hot side outlet of the reboiler is circulated, and the remaining steam condensate after heat exchange is discharged through the water outlet pipeline.

[0045] The toluene oxime pre-separation tower has a feed rate of 37,000 kg / h, with toluene and cyclohexanone oxime mass fractions of 65% and 35%, respectively. The top product is toluene, and the bottom product is a toluene oxime concentrate with mass fractions of 25% and 75%, respectively. The operating pressure of the toluene oxime pre-separation tower is absolute 10-20 kPa, the bottom temperature is 80-90℃, and the required steam condensate flow rate is 72 t / h, with an outlet water temperature of approximately 100℃. If external steam at 0.5 MPaG is used for direct heating, the steam consumption is approximately 5.8 t / h. Utilizing steam condensate can achieve energy savings.

[0046] When the steam condensate inlet flow rate is insufficient, and the inlet flow rate is 36t / h, the steam condensate circulation line is opened and the circulation rate is controlled at 36t / h. At the same time, the steam of the steam condensate heater 1 is turned on to heat the steam condensate, and the heater outlet temperature is adjusted to about 140℃. At this time, the device can still maintain stability.

[0047] Example 2

[0048] This embodiment provides a process for separating ammonia from wastewater using the waste heat of steam condensate, which can be referred to as follows. Figure 1 .

[0049] Steam condensate feed at 140°C and 0.5 MPaG from the steam condensate pipeline is fed into steam condensate buffer tank 2 after passing through steam condensate heater 1. The operating conditions of steam condensate buffer tank 2 include: temperature of 140°C and pressure of 0.26 MPaG.

[0050] After buffering, the steam condensate is pressurized to 0.6 MPaG by the steam condensate circulation pump 3 and then connected to the hot side inlet of the reboiler in the deammoniation tower. A steam condensate circulation pipeline and a water outlet pipeline are installed at the hot side outlet of the reboiler. The steam mixing point of the reboiler hot side outlet and the steam condensate feed pipeline (the distance between the steam mixing point and the steam condensate heater 1 is 30% of the length of the steam condensate feed pipeline) is connected through the steam condensate circulation pipeline. The portion of the heat-exchanged steam condensate at the hot side outlet of the reboiler is circulated, and the remaining portion of the heat-exchanged steam condensate is discharged through the water outlet pipeline.

[0051] The ammonia removal tower has a feed rate of 25,000 kg / h and an ammonia mass fraction of 4%. The top product is ammonia water with an ammonia mass fraction of 25%, while the bottom product is essentially ammonia-free wastewater. The operating pressure of the ammonia removal tower is absolute 75-85 kPa, the bottom temperature is 85-95℃, and the required steam condensate is 55 t / h, with an outlet water temperature of approximately 100℃. If external steam at 0.5 MPaG is used for direct heating, the steam consumption is approximately 4.6 t / h. Utilizing steam condensate can achieve energy savings.

[0052] When the steam condensate inlet flow rate is insufficient and decreases to 30t / h, the steam condensate circulation line is opened and the circulation rate is controlled at 26t / h. At the same time, the steam of the steam condensate heater is turned on to heat the steam condensate, and the heater outlet temperature is adjusted to about 140℃. At this time, the device can still maintain stability.

[0053] The results of the embodiments show that the device described in this utility model can maximize and stably utilize the waste heat of steam condensate, effectively improving energy utilization.

[0054] The preferred embodiments of this utility model have been described in detail above; however, this utility model is not limited thereto. Within the scope of the technical concept of this utility model, various simple modifications can be made to the technical solution of this utility model, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed by this utility model and are all within the protection scope of this utility model.

Claims

1. A steam condensate waste heat recovery device, characterized in that, The device includes a steam condensate heater (1), a steam condensate buffer tank (2), and a downstream application device heater (4); The inlet of the steam condensate heater (1) is connected to the steam condensate feed pipeline; The outlet of the steam condensate heater (1) is connected to the inlet of the steam condensate buffer tank (2); The outlet of the steam condensate buffer tank (2) is connected to the steam condensate inlet of the downstream application device heater (4); The steam condensate outlet of the downstream application device heater (4) is connected to the steam condensate feed pipeline.

2. The apparatus according to claim 1, characterized in that, A steam mixing point is provided on the steam condensate feed pipeline.

3. The apparatus according to claim 2, characterized in that, The steam condensate outlet of the downstream application device heater (4) is connected to the steam mixing point of the steam condensate feed pipeline.

4. The apparatus according to claim 2, characterized in that, The distance between the steam mixing point and the steam condensate heater (1) is 10-90% of the length of the steam condensate feed pipeline.

5. The apparatus according to claim 4, characterized in that, The distance between the steam mixing point and the steam condensate heater (1) is 20-80% of the length of the steam condensate feed pipeline.

6. The apparatus according to claim 1, characterized in that, A steam condensate circulation pipeline is provided at the steam condensate outlet of the downstream application device heater (4).

7. The apparatus according to claim 6, characterized in that, The steam condensate outlet of the downstream application device heater (4) is connected to the steam mixing point through a steam condensate circulation pipeline.

8. The apparatus according to claim 1, characterized in that, A water outlet pipeline is also provided at the steam condensate outlet of the downstream application device heater (4).

9. The apparatus according to any one of claims 1-8, characterized in that, The device also includes a steam condensate circulation pump (3) for delivering the effluent from the steam condensate buffer tank (2) to the downstream application device heater (4).

10. The apparatus according to claim 9, characterized in that, The steam condensate circulating pump (3) is located between the steam condensate buffer tank (2) and the downstream application device heater (4).

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