Dead steam recovery system of low-pressure deaerator

Abstract

The utility model provides a dead steam recovery system of a low-pressure deaerator, and relates to the technical field of dead steam recovery. The dead steam recovery system is used for introducing dead steam generated by the deaerator into the gas-liquid heat exchanger to exchange heat with cold desalted water, condensing water vapor in the dead steam, cooling the dead steam and then emptying the dead steam from an exhaust port of the gas-liquid heat exchanger; the PLC control center intelligently and fully automatically adjusts opening and closing of the pump and opening and closing and opening degrees of all valves according to the temperature and water level information, sensed by the water temperature sensor and the water level sensor, of hot return water in the gas-liquid heat exchanger, and on the basis that it is guaranteed that the temperature and humidity of exhausted steam meet the energy-saving and environment-friendly requirements, hot return water with the appropriate temperature is supplemented for the deaerator, and the deaerator deaerates the exhausted steam. And the reserve quantity of hot return water in the gas-liquid heat exchanger is kept healthy, intelligent and full-automatic recovery of the dead steam of the low-pressure deaerator is achieved, and waste of exhausted steam heat and environmental pollution are avoided.

Description

Technical Field

[0001] This utility model relates to the field of waste steam recovery technology, specifically to a waste steam recovery system for a low-pressure deaerator. Background Technology

[0002] Currently, in thermal power plants and other enterprises with their own boiler systems, low-pressure deaerators are generally used for deoxygenation of boiler feedwater. The working principle of the deaerator is as follows: condensate and makeup water first enter the water chamber of the swirling membrane unit inside the deaerator head. Under a certain water level differential pressure, the water is sprayed obliquely from the small holes of the membrane tubes into the inner hole, forming a jet. Since the inner hole is filled with rising heating steam, the water entrains a large amount of heating steam during the jet motion. This generates a violent mixing and heating effect in a very short time and a very small stroke, significantly increasing the water temperature. The rotating water continues to swirl down along the inner wall of the membrane tube, forming a rolling water film skirt. The critical Reynolds number of the water during the swirling flow decreases significantly, resulting in turbulent rolling. At this point, the heat and mass transfer effect of the turbulent water is ideal, and the water temperature reaches the saturation temperature. Oxygen is then separated. Because oxygen cannot diffuse freely within the inner hole, it can only be discharged into the atmosphere through the exhaust pipe with the rising steam. However, the exhaust steam released into the atmosphere not only has a very high temperature, causing heat waste, but also causes enterprises to lose a lot of water resources due to the long-term release of exhaust steam, and the emitted steam will also cause certain thermal pollution to the environment. Utility Model Content

[0003] To address the shortcomings of existing technologies, this utility model provides a low-pressure deaerator exhaust steam recovery system, which solves the problems of heat waste and environmental pollution caused by exhaust steam emissions from low-pressure deaerators.

[0004] To achieve the above objectives, this utility model provides the following technical solution:

[0005] A low-pressure deaerator exhaust steam recovery system, the exhaust steam recovery system comprising: a gas-liquid heat exchanger, an exhaust steam recovery pipe, an inlet pipe, an outlet pipe, and a pump;

[0006] The gas-liquid heat exchanger is provided with an air inlet, an exhaust outlet, a liquid inlet, and a liquid outlet;

[0007] The air inlet of the gas-liquid heat exchanger is connected to the exhaust steam discharge pipe of the deaerator through the exhaust steam recovery pipe. The exhaust steam generated by the deaerator enters the gas-liquid heat exchanger through the exhaust steam recovery pipe to recover heat and condense into water vapor before being discharged through the exhaust port. The liquid inlet is connected to the demineralized water supply device through the liquid inlet pipe. The demineralized water in the demineralized water supply device enters the gas-liquid heat exchanger through the liquid inlet pipe. The liquid outlet is connected to the water supply port of the deaerator through the liquid outlet pipe. The condensate and demineralized water that have absorbed heat in the deaerator are used as hot return water to supply water to the deaerator through the liquid outlet pipe.

[0008] A pump is installed on the drain pipe, which provides driving force for supplying water to the deaerator.

[0009] Preferably, the waste steam discharge pipe is equipped with a waste steam discharge valve, which is located downstream of the waste steam recovery pipe and is closed during the waste steam recovery process.

[0010] Preferably, the waste steam recovery pipe is equipped with a waste steam recovery valve, which is opened during the waste steam recovery process.

[0011] Preferably, the inlet pipe is equipped with an inlet valve.

[0012] Preferably, the drain pipe is equipped with a drain valve.

[0013] Preferably, the bottom of the gas-liquid heat exchanger is provided with a water temperature sensor and a water level sensor to sense the temperature and water level of the hot return water in the gas-liquid heat exchanger.

[0014] Preferably, the waste steam recovery system further includes: a PLC control center;

[0015] The PLC control center is electrically connected to the pump, exhaust steam valve, exhaust steam recovery valve, liquid inlet valve, liquid outlet valve, water temperature sensor, and water level sensor, respectively.

[0016] Preferably, the liquid inlet valve is provided with a threshold opening, which is the minimum opening of the liquid inlet valve to meet the energy-saving and environmental protection requirements; that is, when the exhaust steam discharge valve is closed and the exhaust steam recovery valve is fully open, when the liquid inlet valve opening is adjusted to the threshold opening, the temperature of the exhaust steam released from the exhaust port is not higher than the temperature required for energy saving and environmental protection; when the liquid inlet valve opening is less than the threshold opening, the temperature of the exhaust steam released from the exhaust port is higher than the temperature required for energy saving and environmental protection.

[0017] This invention provides a low-pressure deaerator exhaust steam recovery system. Compared with the prior art, it has the following advantages:

[0018] In this invention, the waste steam recovery system introduces waste steam generated by the deaerator into a gas-liquid heat exchanger to exchange heat with cold demineralized water. The water vapor in the waste steam is condensed, and the waste steam is cooled before being vented from the exhaust port of the gas-liquid heat exchanger. The PLC control center intelligently and automatically adjusts the pump's start / stop, and the opening and closing of various valves based on the temperature and water level information of the hot return water in the gas-liquid heat exchanger sensed by the water temperature and water level sensors. While ensuring that the temperature and humidity of the vented waste steam meet energy-saving and environmental protection requirements, it replenishes the deaerator with hot return water at a suitable temperature and maintains a healthy reserve of hot return water in the gas-liquid heat exchanger. This achieves intelligent and fully automatic recovery of waste steam from the low-pressure deaerator, avoiding the waste of heat from waste steam emissions and environmental pollution. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the waste steam recovery system in an embodiment of this utility model.

[0021] The attached diagram is labeled as follows: 1. Gas-liquid heat exchanger; 2. Waste steam recovery pipe; 3. Liquid inlet pipe; 4. Liquid outlet pipe; 5. Pump; 6. Deaerator; 7. Waste steam discharge pipe; 8. Waste steam exhaust valve; 9. Waste steam recovery valve; 10. Liquid inlet valve; 11. Liquid outlet valve; 12. PLC control center. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments of this utility model are described clearly and completely. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0023] This application provides a low-pressure deaerator exhaust steam recovery system, which solves the problems of heat waste and environmental pollution caused by exhaust steam from low-pressure deaerators.

[0024] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0025] Example:

[0026] like Figure 1 As shown, this utility model provides a low-pressure deaerator exhaust steam recovery system, which includes: a gas-liquid heat exchanger 1, an exhaust steam recovery pipe 2, an inlet pipe 3, an outlet pipe 4, and a pump 5;

[0027] The gas-liquid heat exchanger 1 is provided with an air inlet, an exhaust outlet, a liquid inlet, and a liquid outlet;

[0028] The air inlet of the gas-liquid heat exchanger 1 is connected to the exhaust steam discharge pipe 7 of the deaerator 6 through the exhaust steam recovery pipe 2. The exhaust steam generated by the deaerator 6 enters the gas-liquid heat exchanger 1 through the exhaust steam recovery pipe 2 to recover heat and condense water vapor before being discharged through the exhaust port. The liquid inlet is connected to the demineralized water supply device through the liquid inlet pipe 3. The demineralized water in the demineralized water supply device enters the gas-liquid heat exchanger 1 through the liquid inlet pipe 3. The liquid outlet is connected to the water supply port of the deaerator 6 through the liquid outlet pipe 4. The condensate and demineralized water in the deaerator 6 are used as hot return water to supply water to the deaerator 6 through the liquid outlet pipe 4.

[0029] A pump 5 is installed on the drain pipe 4, and the pump 5 provides driving force for supplying water to the deaerator 6.

[0030] like Figure 1 As shown, the exhaust steam discharge pipe 7 is equipped with an exhaust steam discharge valve 8, which is located downstream of the exhaust steam recovery pipe 2. During the exhaust steam recovery process, the exhaust steam discharge valve 8 is closed.

[0031] like Figure 1 As shown, the waste steam recovery pipe 2 is equipped with a waste steam recovery valve 9, which is opened during the waste steam recovery process.

[0032] like Figure 1 As shown, the liquid inlet pipe 3 is equipped with a liquid inlet valve 10.

[0033] like Figure 1 As shown, the drain pipe 4 is equipped with a drain valve 11.

[0034] The bottom of the gas-liquid heat exchanger 1 is equipped with a water temperature sensor and a water level sensor to sense the temperature and water level of the hot return water in the gas-liquid heat exchanger 1.

[0035] like Figure 1 As shown, the waste steam recovery system also includes: a PLC control center 12;

[0036] The PLC control center 12 is electrically connected to the pump 5, the exhaust steam valve 8, the exhaust steam recovery valve 9, the liquid inlet valve 10, the liquid outlet valve 11, the water temperature sensor, and the water level sensor.

[0037] The gas-liquid heat exchanger 1 is existing technology and will not be described in detail here. The demineralized water enters the gas-liquid heat exchanger 1 and exchanges heat with the exhaust steam to generate hot return water, which is stored in the gas-liquid heat exchanger 1. The PLC control center 12 controls the opening and closing of each valve and pump 5 and the degree of opening based on the sensing information from the water temperature sensor and the water level sensor.

[0038] The temperature of the demineralized water supplied by the demineralized water supply device is not higher than 23°C.

[0039] The liquid inlet valve 10 is equipped with a threshold opening degree, which is the minimum opening degree of the liquid inlet valve 10 to meet the energy-saving and environmental protection requirements. That is, when the exhaust steam discharge valve 8 is closed and the exhaust steam recovery valve 9 is fully open, when the opening degree of the liquid inlet valve 10 is adjusted to the threshold opening degree, the temperature of the exhaust steam released from the exhaust port is not higher than the temperature required for energy saving and environmental protection. When the opening degree of the liquid inlet valve 10 is less than the threshold opening degree, the temperature of the exhaust steam released from the exhaust port is higher than the temperature required for energy saving and environmental protection.

[0040] The method of using the waste steam recovery system includes the following steps:

[0041] S1. Close the exhaust steam discharge valve 8, open the exhaust steam recovery valve 9 and the liquid inlet valve 10. The exhaust steam and demineralized water exchange heat in the gas-liquid heat exchanger 1. The demineralized water and the condensate of water vapor in the exhaust steam after absorbing heat are stored as heat return water in the gas-liquid heat exchanger 1. The exhaust steam after heat exchange is released through the exhaust port.

[0042] S2. Set the high temperature threshold, alarm high temperature threshold, low temperature threshold, unit response time, opening adjustment unit, threshold opening, high threshold and low threshold through the PLC control center 12;

[0043] S3. The PLC control center 12 adjusts the opening of the inlet valve 10 according to the hot return water temperature sensed by the water temperature sensor. When the hot return water temperature is higher than the high temperature threshold, the PLC control center 12 controls the opening of the inlet valve 10 to increase by one unit. After one unit reaction time, if the hot return water temperature is lower than the high temperature threshold, the opening of the inlet valve 10 will no longer be adjusted. If the hot return water temperature is still higher than the high temperature threshold, the PLC control center 12 controls the opening of the inlet valve 10 to increase by another unit. Then, every unit reaction time, the sensing and opening adjustment operation is repeated until the hot return water temperature is lower than the high temperature threshold.

[0044] When the temperature of the hot return water exceeds the alarm high temperature threshold, the PLC control center 12 controls the liquid inlet valve 10 to open to the maximum.

[0045] When the temperature of the hot return water is lower than the low temperature threshold, the PLC control center 12 controls the opening of the liquid inlet valve 10 to be reduced to the threshold opening.

[0046] S4. PLC control center 12 starts pump 5 and opens drain valve 11;

[0047] S5.PLC control center 12 adjusts the opening of drain valve 11 according to the amount of hot return water stored by the water level sensor; when the hot return water level is higher than the high threshold, the opening of drain valve 11 is adjusted according to the opening of inlet valve 10 at this time, so that the drain flow rate is greater than the inlet flow rate; when the hot return water level is lower than the low threshold, the opening of drain valve 11 is adjusted according to the opening of inlet valve 10 at this time, so that the drain flow rate is less than the inlet flow rate.

[0048] S6. After the deaerator 6 stops working, the PLC control center 12 opens the exhaust steam discharge valve 8 and gradually closes the exhaust steam recovery valve 9, liquid inlet valve 10, pump 5 and liquid outlet valve 11.

[0049] The high temperature threshold is set to 60-65℃; the alarm high temperature threshold is set to 70-80℃; and the low temperature threshold is set to 35-40℃.

[0050] In summary, compared with the prior art, the present invention has the following beneficial effects:

[0051] In this embodiment of the invention, the waste steam recovery system introduces the waste steam generated by the deaerator 6 into the gas-liquid heat exchanger 1 for heat exchange with the cold demineralized water. The water vapor in the waste steam is condensed, and the waste steam is cooled before being vented from the exhaust port of the gas-liquid heat exchanger 1. The PLC control center 12 intelligently and automatically adjusts the start and stop of the pump 5, the opening and closing of each valve, and the opening degree based on the temperature and water level information of the hot return water in the gas-liquid heat exchanger 1 sensed by the water temperature sensor and water level sensor. While ensuring that the temperature and humidity of the vented waste steam meet energy-saving and environmental protection requirements, it replenishes the deaerator 6 with hot return water at a suitable temperature and maintains a healthy storage level of hot return water in the gas-liquid heat exchanger 1. This achieves intelligent and fully automatic recovery of the waste steam from the low-pressure deaerator, avoiding the waste of heat from waste steam emissions and environmental pollution. Traditional deaerators use 10t / h of 0.5MPa steam; deaerator 6 uses 8t / h of 0.5MPa steam, resulting in annual cost savings of approximately 1.02 million yuan.

[0052] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0053] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A low-pressure deaerator exhaust steam recovery system, characterized in that, The waste steam recovery system includes: a gas-liquid heat exchanger (1), a waste steam recovery pipe (2), a liquid inlet pipe (3), a liquid outlet pipe (4), and a pump (5); The gas-liquid heat exchanger (1) is provided with an air inlet, an exhaust outlet, a liquid inlet, and a liquid outlet; The inlet of the gas-liquid heat exchanger (1) is connected to the exhaust steam discharge pipe (7) of the deaerator (6) through the exhaust steam recovery pipe (2). The exhaust steam generated by the deaerator (6) enters the gas-liquid heat exchanger (1) through the exhaust steam recovery pipe (2) to recover heat and condense water vapor before being discharged through the exhaust port. The liquid inlet is connected to the demineralized water supply device through the liquid inlet pipe (3). The demineralized water in the demineralized water supply device enters the gas-liquid heat exchanger (1) through the liquid inlet pipe (3). The liquid outlet is connected to the water supply port of the deaerator (6) through the liquid outlet pipe (4). The condensate in the deaerator (6) and the demineralized water after absorbing heat are used as hot return water to supply water to the deaerator (6) through the liquid outlet pipe (4). A pump (5) is installed on the drain pipe (4), and the pump (5) provides driving force for supplying water to the deaerator (6).

2. The low-pressure deaerator exhaust steam recovery system as described in claim 1, characterized in that, The exhaust steam discharge pipe (7) is equipped with an exhaust steam discharge valve (8), which is located downstream of the exhaust steam recovery pipe (2). During the exhaust steam recovery process, the exhaust steam discharge valve (8) is closed.

3. The low-pressure deaerator exhaust steam recovery system as described in claim 1, characterized in that, The waste steam recovery pipe (2) is equipped with a waste steam recovery valve (9), which is opened during the waste steam recovery process.

4. The low-pressure deaerator exhaust steam recovery system as described in claim 1, characterized in that, The inlet pipe (3) is equipped with an inlet valve (10).

5. The low-pressure deaerator exhaust steam recovery system as described in claim 1, characterized in that, The drain pipe (4) is equipped with a drain valve (11).

6. The low-pressure deaerator exhaust steam recovery system as described in claim 1, characterized in that, The bottom of the gas-liquid heat exchanger (1) is equipped with a water temperature sensor and a water level sensor to sense the temperature and water level of the hot return water in the gas-liquid heat exchanger (1).

7. The low-pressure deaerator exhaust steam recovery system as described in claim 1, characterized in that, The waste steam recovery system also includes: a PLC control center (12); The PLC control center (12) is electrically connected to the pump (5), the exhaust steam valve (8), the exhaust steam recovery valve (9), the liquid inlet valve (10), the liquid outlet valve (11), the water temperature sensor, and the water level sensor, respectively.

8. The low-pressure deaerator exhaust steam recovery system as described in claim 4, characterized in that, The liquid inlet valve (10) is provided with a threshold opening degree. The threshold opening degree is the minimum opening degree of the liquid inlet valve (10) to meet the energy-saving and environmental protection requirements. That is, when the exhaust steam discharge valve (8) is closed and the exhaust steam recovery valve (9) is fully open, the temperature of the exhaust steam released from the exhaust port is not higher than the temperature required for energy saving and environmental protection when the opening degree of the liquid inlet valve (10) is adjusted to the threshold opening degree. When the opening degree of the liquid inlet valve (10) is less than the threshold opening degree, the temperature of the exhaust steam released from the exhaust port is higher than the temperature required for energy saving and environmental protection.

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