Dead steam recovery system and process for low-pressure deaerator

Abstract

The invention provides a waste steam recovery system and process for a low-pressure deaerator, and relates to the technical field of waste 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] The invention relates to the technical field of exhaust steam recovery, and in particular to an exhaust steam recovery system and process for a low-pressure deaerator. Background Art

[0002] At present, thermal power plants and other enterprises with self-built boiler devices generally use low-pressure deaerators for deoxygenation of boiler feed water. The working principle of the deaerator is: the condensate and make-up water first enter the water chamber of the rotary membrane group in the deaerator head, and under a certain water level differential pressure, it is sprayed obliquely from the small hole of the membrane tube to the inner hole to form a jet. Since the inner hole is filled with rising heating steam, the water will absorb a large amount of heating steam in the jet movement; in a very short time and a small stroke, a violent mixing and heating effect is produced, the water temperature is greatly increased, and the rotating water continues to rotate down along the inner hole wall of the membrane tube to form a rolling water film skirt. The critical Reynolds number of water in the rotating flow drops a lot, that is, turbulent rolling occurs. At this time, the heat and mass transfer effect of water in the turbulent state is the most ideal, and the water temperature reaches the saturation temperature. Oxygen is separated, because oxygen cannot diffuse freely in the inner hole, it can only be discharged to the atmosphere from the exhaust pipe with the rising steam. However, the exhaust steam discharged into the atmosphere not only has a very high temperature, resulting in heat waste, but also causes the enterprise to lose a large amount of water resources due to the long-term exhaust steam discharge. At the same time, the discharged steam will also cause certain thermal pollution to the environment. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a low-pressure deaerator exhaust steam recovery system and process, which solves the problem of heat waste and environmental pollution caused by exhaust steam emission from the low-pressure deaerator.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solutions:

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

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

[0007] The air inlet of the gas-liquid heat exchanger is connected with the exhaust steam discharge pipe of the deaerator through the exhaust steam recovery pipe, and the exhaust steam generated by the deaerator enters the gas-liquid heat exchanger through the exhaust steam recovery pipe to recover heat and condense water vapor before being discharged through the exhaust port; the liquid inlet is connected with the desalted water supply device through the liquid inlet pipe, and the desalted water in the desalted water supply device enters the gas-liquid heat exchanger through the liquid inlet pipe; the liquid discharge port is connected with the water supply port of the deaerator through the liquid discharge pipe, and the condensed water in the deaerator and the desalted water after absorbing heat are used as hot return water to supply water to the deaerator through the liquid discharge pipe;

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

[0009] Preferably, the exhaust steam discharge pipe is provided with an exhaust steam discharge valve, which is located downstream of the exhaust steam recovery pipe, and the exhaust steam discharge valve is closed during the exhaust steam recovery process.

[0010] Preferably, the exhaust steam recovery pipe is provided with an exhaust steam recovery valve, and the exhaust steam recovery valve is opened during the exhaust steam recovery process.

[0011] Preferably, the liquid inlet pipe is provided with a liquid inlet valve.

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

[0013] Preferably, a water temperature sensor and a water level sensor are provided at the bottom of the gas-liquid heat exchanger for sensing the temperature and water level of the hot return water in the gas-liquid heat exchanger.

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

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

[0016] A low-pressure deaerator exhaust steam recovery process, the exhaust steam recovery process comprising the following steps:

[0017] S1. Close the exhaust steam discharge valve, open the exhaust steam recovery valve and the liquid inlet valve, and the exhaust steam and desalted water exchange heat in the gas-liquid heat exchanger. The desalted water after absorbing heat and the condensed water from the water vapor in the exhaust steam are stored in the gas-liquid heat exchanger as hot return water. The exhaust steam after heat exchange is discharged through the exhaust port;

[0018] S2. Set the high temperature threshold, high temperature alarm threshold, low temperature threshold, unit response time, opening adjustment unit, threshold opening, high threshold and low threshold through the PLC control center;

[0019] S3. The PLC control center adjusts the opening of the liquid inlet valve 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 controls the liquid inlet valve to open one unit larger; after a unit reaction time, if the hot return water temperature is lower than the high temperature threshold, the liquid inlet valve opening is no longer adjusted; if the hot return water temperature is still higher than the high temperature threshold, the PLC control center controls the liquid inlet valve to open one unit larger, and then repeats the sensing and opening adjustment operations every unit reaction time until the hot return water temperature is lower than the high temperature threshold;

[0020] When the hot return water temperature is higher than the high temperature alarm threshold, the PLC control center controls the liquid inlet valve to open to the maximum;

[0021] When the hot return water temperature is lower than the low temperature threshold, the PLC control center controls the liquid inlet valve opening to be reduced to the threshold opening;

[0022] S4.PLC control center starts the pump and opens the discharge valve;

[0023] S5. The PLC control center adjusts the opening of the drain valve according to the hot return water storage volume sensed by the water level sensor; when the hot return water level is higher than the high threshold, the drain valve opening is adjusted according to the opening of the inlet valve at this time, so that the discharge flow is greater than the inlet flow; when the hot return water level is lower than the low threshold, the drain valve opening is adjusted according to the opening of the inlet valve at this time, so that the discharge flow is less than the inlet flow;

[0024] S6. After the deaerator stops working, the PLC control center opens the exhaust steam discharge valve and gradually closes the exhaust steam recovery valve, liquid inlet valve, pump and discharge valve.

[0025] Preferably, the threshold opening is the minimum opening of the liquid inlet valve that meets the requirements of energy conservation and environmental protection; that is, when the exhaust steam discharge valve is closed and the exhaust steam recovery valve is fully opened, when the opening of the liquid inlet valve is adjusted to the threshold opening, the temperature of the exhaust steam discharged from the exhaust port is not higher than the temperature required for energy conservation and environmental protection; when the opening of the liquid inlet valve is less than the threshold opening, the temperature of the exhaust steam discharged from the exhaust port is higher than the temperature required for energy conservation and environmental protection.

[0026] Preferably, the high temperature threshold is set to 60-65°C; the alarm high temperature threshold is set to 70-80°C; and the low temperature threshold is set to 35-40°C.

[0027] The present invention provides a low-pressure deaerator exhaust steam recovery system and process. Compared with the prior art, it has the following beneficial effects:

[0028] In the present invention, the exhaust steam recovery system passes the exhaust steam generated by the deaerator into the gas-liquid heat exchanger for heat exchange with cold desalted water, condenses the water vapor in the exhaust steam, cools the exhaust steam, and then discharges it from the exhaust port of the gas-liquid heat exchanger; the PLC control center intelligently and automatically adjusts the opening and closing of the pump, the opening and closing and the opening degree of each valve according to the temperature and water level information of the hot return water in the gas-liquid heat exchanger sensed by the water temperature sensor and the water level sensor, and on the basis of ensuring that the temperature and humidity of the discharged exhaust steam meet the requirements of energy saving and environmental protection, the deaerator is supplemented with hot return water with suitable temperature, and the reserves of hot return water in the gas-liquid heat exchanger are maintained healthy, so as to realize the intelligent and automatic recovery of the exhaust steam of the low-pressure deaerator, and avoid the waste of exhaust steam discharge heat and pollution of the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 Schematic diagram of the structure of the exhaust steam recovery system in an embodiment of the present invention.

[0031] Figure 2 Schematic diagram of the process of exhaust steam recovery in an embodiment of the present invention.

[0032] The reference numerals in the figure are set as: gas-liquid heat exchanger 1, exhaust steam recovery pipe 2, liquid inlet pipe 3, liquid discharge pipe 4, pump 5, deaerator 6, exhaust steam discharge pipe 7, exhaust steam external discharge valve 8, exhaust steam recovery valve 9, liquid inlet valve 10, liquid discharge valve 11, PLC control center 12. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The embodiments of the present application provide a low-pressure deaerator exhaust steam recovery system and process, thereby solving the problem of heat waste and environmental pollution caused by exhaust steam emission from a low-pressure deaerator.

[0035] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0036] Example:

[0037] like Figure 1 As shown, the present invention provides a low-pressure deaerator exhaust steam recovery system, the exhaust steam recovery system comprising: a gas-liquid heat exchanger 1, an exhaust steam recovery pipe 2, a liquid inlet pipe 3, a liquid discharge pipe 4 and a pump 5;

[0038] The gas-liquid heat exchanger 1 is provided with: an air inlet, an exhaust port, a liquid inlet and a liquid discharge port;

[0039] The air inlet of the gas-liquid heat exchanger 1 is connected with the exhaust steam discharge pipe 7 of the deaerator 6 through the exhaust steam recovery pipe 2, and 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 with the desalted water supply device through the liquid inlet pipe 3, and the desalted water in the desalted water supply device enters the gas-liquid heat exchanger 1 through the liquid inlet pipe 3; the liquid discharge port is connected with the water supply port of the deaerator 6 through the liquid discharge pipe 4, and the condensed water in the deaerator 6 and the desalted water after absorbing heat are used as hot return water to supply water to the deaerator 6 through the liquid discharge pipe 4;

[0040] A pump 5 is installed on the liquid discharge pipe 4 , and the pump 5 provides driving force for supplying water to the deaerator 6 .

[0041] like Figure 1 As shown, the exhaust steam discharge pipe 7 is provided with an exhaust steam discharge valve 8, and the exhaust steam discharge valve 8 is located downstream of the exhaust steam recovery pipe 2. The exhaust steam discharge valve 8 is closed during the exhaust steam recovery process.

[0042] like Figure 1 As shown, the exhaust steam recovery pipe 2 is provided with an exhaust steam recovery valve 9, and the exhaust steam recovery valve 9 is opened during the exhaust steam recovery process.

[0043] like Figure 1 As shown, the liquid inlet pipe 3 is provided with a liquid inlet valve 10 .

[0044] like Figure 1 As shown, the drain pipe 4 is provided with a drain valve 11 .

[0045] A water temperature sensor and a water level sensor are provided at the bottom of the gas-liquid heat exchanger 1 for sensing the temperature and water level of the hot return water in the gas-liquid heat exchanger 1 .

[0046] like Figure 1 As shown, the exhaust steam recovery system further includes: a PLC control center 12;

[0047] The PLC control center 12 is electrically connected to the pump 5 , the exhaust steam discharge valve 8 , the exhaust steam recovery valve 9 , the liquid inlet valve 10 , the liquid discharge valve 11 , the water temperature sensor and the water level sensor respectively.

[0048] The gas-liquid heat exchanger 1 is a prior art and will not be described in detail here. The hot return water generated by the desalted water entering the gas-liquid heat exchanger 1 and exchanging heat with the exhaust steam is stored in the gas-liquid heat exchanger 1. The PLC control center 12 controls the switches and opening degrees of each valve and pump 5 according to the sensing information of the water temperature sensor and the water level sensor.

[0049] The temperature of the desalted water supplied by the desalted water supply device is not higher than 23°C.

[0050] like Figure 2 As shown, the present invention provides a low-pressure deaerator exhaust steam recovery process, and the exhaust steam recovery process includes the following steps:

[0051] S1. Close the exhaust steam discharge valve 8, open the exhaust steam recovery valve 9 and the liquid inlet valve 10, and the exhaust steam and the desalted water are exchanged in the gas-liquid heat exchanger 1. The desalted water after absorbing the heat and the condensed water of the water vapor in the exhaust steam are stored in the gas-liquid heat exchanger 1 as hot return water, and the exhaust steam after the heat exchange is discharged through the exhaust port;

[0052] S2. Set the high temperature threshold, high temperature alarm threshold, low temperature threshold, unit response time, opening adjustment unit, threshold opening, high threshold and low threshold through the PLC control center 12;

[0053] S3. The PLC control center 12 adjusts the opening of the liquid 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 liquid inlet valve 10 to be increased by one unit; after a unit reaction time, if the hot return water temperature is lower than the high temperature threshold, the opening of the liquid inlet valve 10 is no longer 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 liquid inlet valve 10 to be increased by one unit again, and then repeats the sensing and opening adjustment operations every unit reaction time until the hot return water temperature is lower than the high temperature threshold;

[0054] When the hot return water temperature is higher than the alarm high temperature threshold, the PLC control center 12 controls the liquid inlet valve 10 to open to the maximum;

[0055] When the hot return water temperature 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;

[0056] S4. The PLC control center 12 starts the pump 5 and opens the discharge valve 11;

[0057] S5. The PLC control center 12 adjusts the opening of the drain valve 11 according to the hot return water storage volume sensed by the water level sensor; when the hot return water level is higher than the high threshold, the opening of the drain valve 11 is adjusted according to the opening of the inlet valve 10 at this time, so that the discharge flow is greater than the inlet flow; when the hot return water level is lower than the low threshold, the opening of the drain valve 11 is adjusted according to the opening of the inlet valve 10 at this time, so that the discharge flow is less than the inlet flow;

[0058] 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, the liquid inlet valve 10, the pump 5 and the liquid discharge valve 11.

[0059] The threshold opening is the minimum opening of the liquid inlet valve 10 that meets the requirements of energy conservation and environmental protection; that is, when the exhaust steam discharge valve 8 is closed and the exhaust steam recovery valve 9 is fully opened, when the opening of the liquid inlet valve 10 is adjusted to the threshold opening, the temperature of the exhaust steam discharged from the exhaust port is not higher than the temperature required for energy conservation and environmental protection; when the opening of the liquid inlet valve 10 is less than the threshold opening, the temperature of the exhaust steam discharged from the exhaust port is higher than the temperature required for energy conservation and environmental protection.

[0060] The high temperature threshold is set to 60-65°C; the alarm high temperature threshold is set to 70-80°C; and the low temperature threshold is set to 35-40°C.

[0061] In summary, compared with the prior art, the present invention has the following beneficial effects:

[0062] In the embodiment of the present invention, the exhaust steam recovery system passes the exhaust steam generated by the deaerator 6 into the gas-liquid heat exchanger 1 for heat exchange with cold desalted water, condenses the water vapor in the exhaust steam, cools the exhaust steam, and then discharges it from the exhaust port of the gas-liquid heat exchanger 1; the PLC control center 12 intelligently and automatically adjusts the opening and closing of the pump 5, the opening and closing and the opening degree of each valve according to 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 the water level sensor, and on the basis of ensuring that the temperature and humidity of the exhausted steam meet the requirements of energy saving and environmental protection, the deaerator 6 is supplemented with hot return water of suitable temperature, and the reserve of hot return water in the gas-liquid heat exchanger 1 is maintained healthy, so as to realize the intelligent and automatic recovery of the exhaust steam of the low-pressure deaerator, and avoid the waste of exhaust steam discharge heat and pollution of the environment; the traditional deaerator uses 10t / h of 0.5MPa steam; the deaerator 6 uses 8t / h of 0.5MPa steam, saving about 1.02 million yuan per year.

[0063] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0064] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-pressure deaerator exhaust steam recovery system, characterized in that: The exhaust steam recovery system comprises: a gas-liquid heat exchanger (1), an exhaust steam recovery pipe (2), a liquid inlet pipe (3), a liquid discharge pipe (4) and a pump (5); The gas-liquid heat exchanger (1) is provided with: an air inlet, an air outlet, a liquid inlet and a liquid outlet; 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), and 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 desalted water supply device through the liquid inlet pipe (3), and the desalted water in the desalted water supply device enters the gas-liquid heat exchanger (1) through the liquid inlet pipe (3); the liquid discharge port is connected to the water supply port of the deaerator (6) through the liquid discharge pipe (4), and the condensed water in the deaerator (6) and the desalted water after absorbing heat are used as hot return water to supply water to the deaerator (6) through the liquid discharge pipe (4); A pump (5) is installed on the liquid discharge 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 according to claim 1, characterized in that: The exhaust steam discharge pipe (7) is provided with an exhaust steam discharge valve (8), which is located downstream of the exhaust steam recovery pipe (2). The exhaust steam discharge valve (8) is closed during the exhaust steam recovery process.

3. The low-pressure deaerator exhaust steam recovery system according to claim 1, characterized in that: The exhaust steam recovery pipe (2) is provided with an exhaust steam recovery valve (9), and the exhaust steam recovery valve (9) is opened during the exhaust steam recovery process.

4. The low-pressure deaerator exhaust steam recovery system according to claim 1, characterized in that: The liquid inlet pipe (3) is provided with a liquid inlet valve (10).

5. The low-pressure deaerator exhaust steam recovery system according to claim 1, characterized in that: The liquid discharge pipe (4) is provided with a liquid discharge valve (11).

6. The low-pressure deaerator exhaust steam recovery system according to claim 1, characterized in that: A water temperature sensor and a water level sensor are arranged at the bottom of the gas-liquid heat exchanger (1) for sensing the temperature and water level of hot return water in the gas-liquid heat exchanger (1).

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

8. A low-pressure deaerator exhaust steam recovery process, characterized in that: The exhaust steam recovery process comprises the following steps: S1. The exhaust steam discharge valve (8) is closed, and the exhaust steam recovery valve (9) and the liquid inlet valve (10) are opened. The exhaust steam and the desalted water are exchanged with each other in the gas-liquid heat exchanger (1). The desalted water and the condensed water from the water vapor in the exhaust steam are stored as hot return water in the gas-liquid heat exchanger (1). The exhaust steam after the heat exchange is discharged through the exhaust port. S2. Setting the high temperature threshold, high temperature alarm threshold, low temperature threshold, unit response time, opening adjustment unit, threshold opening, high threshold and low threshold through the PLC control center (12); S3. The PLC control center (12) adjusts the opening of the liquid 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 liquid inlet valve (10) to be increased by one unit; after a unit reaction time, if the hot return water temperature is lower than the high temperature threshold, the opening of the liquid inlet valve (10) is no longer 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 liquid inlet valve (10) to be increased by one unit again, and then repeats the sensing and opening adjustment operations every unit reaction time until the hot return water temperature is lower than the high temperature threshold; When the hot return water temperature is higher than the high temperature alarm threshold, the PLC control center (12) controls the liquid inlet valve (10) to open to the maximum; When the hot return water temperature 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; S4. The PLC control center (12) starts the pump (5) and opens the discharge valve (11); S5. The PLC control center (12) adjusts the opening of the drain valve (11) according to the hot return water storage volume sensed by the water level sensor; when the hot return water level is higher than the high threshold, the opening of the drain valve (11) is adjusted according to the opening of the inlet valve (10) at this time, so that the discharge flow rate is greater than the inlet flow rate; when the hot return water level is lower than the low threshold, the opening of the drain valve (11) is adjusted according to the opening of the inlet valve (10) at this time, so that the discharge flow rate is less than the inlet flow rate; 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), the liquid inlet valve (10), the pump (5) and the liquid discharge valve (11).

9. The low-pressure deaerator exhaust steam recovery process according to claim 8, characterized in that: The threshold opening is the minimum opening of the liquid inlet valve (10) that meets 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 opened, when the opening of the liquid inlet valve (10) is adjusted to the threshold opening, the temperature of the exhaust steam discharged from the exhaust port is not higher than the energy-saving and environmental protection required temperature; when the opening of the liquid inlet valve (10) is less than the threshold opening, the temperature of the exhaust steam discharged from the exhaust port is higher than the energy-saving and environmental protection required temperature.

10. The low-pressure deaerator exhaust steam recovery process according to claim 8, characterized in that: The high temperature threshold is set to 60-65°C; the alarm high temperature threshold is set to 70-80°C; and the low temperature threshold is set to 35-40°C.

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