Dead steam recovery process system for oxygen exhaust door of deaerator

Abstract

The technical problem to be solved by the utility model is to provide the dead steam recovery process system for the oxygen exhaust door of the deaerator, dead steam can be selectively guided into an air cooling recovery device, white pollution caused by dead steam emission to the field environment is eliminated, dead steam condensate is recovered to a drain tank and enters the deaerator again for use, and the dead steam recovery process system has the advantages of being simple in structure and convenient to operate. The system comprises a deaerator system, the deaerator system comprises a plurality of deaerators distributed in parallel, the system further comprises an air cooling and recycling device, and the air cooling and recycling device comprises a heat exchange tube bundle, a dead steam diffusion chamber and a condensate recycling and storing chamber; the heat exchange tube bundle is transversely arranged in the frame, the inlet end of the heat exchange tube bundle is communicated with the dead steam diffusion chamber, and the outlet end of the heat exchange tube bundle is communicated with the condensate recovery and storage chamber.

Description

Technical Field

[0001] The utility model relates to a deaerator cooling rain in the field of thermal deoxidation in a thermal power plant, and in particular to a deaerator exhaust door exhaust steam recovery process system. Background Art

[0002] At present, thermal power plants mostly use thermal deoxygenation technology to remove dissolved oxygen in boiler feed water. Dalton's law and Henry's law are used to heat the feed water with steam to increase the water temperature, so that the partial pressure of steam on the water surface gradually increases, while the partial pressure of dissolved gas gradually decreases, and the gas dissolved in the water continues to escape. When the water is heated to the boiling temperature under the corresponding pressure, the water surface is full of water vapor, and the partial pressure of dissolved gas is zero. Water no longer has the ability to dissolve gas, that is, the gas dissolved in the water, including oxygen, can be removed.

[0003] At present, Luxi Group Power Branch has three high-pressure deaerators with a rated load of 680 tons, operating pressure of 0.55MPa, temperature of 155℃, and one low-pressure deaerator, operating pressure of 0.20Mpa, temperature of 120℃. Our company's four deaerators all use the principle of thermal deaeration to remove oxygen from the deoxygenated feed water. In order to ensure that the dissolved oxygen index of the deoxygenated feed water is qualified (controlled at ≤7ug / l), it is necessary to use the discharge pressure of the deaerator tower head to continuously discharge a large amount of exhaust steam into the atmosphere through the oxygen discharge door. At that time, the oxygen exhaust door opening of the four deaerators was about 5%, and about 5 tons of exhaust steam were discharged per hour. When the load was high, the oxygen exhaust door opening would be increased. Such discharge without any control measures on the oxygen exhaust door opening would directly cause two disadvantages: First, the oxygen exhaust door opening was too large, resulting in direct exhaust waste of deoxygenated exhaust steam, large heat loss (the thermal enthalpy of this part of saturated steam is 653.92kj / kg), a large amount of hot working fluid could not be effectively utilized, the thermal efficiency was low, the unit consumption of deoxygenated steam increased, the economy was poor, and visually caused white pollution to the power plant environment. Second, the oxygen exhaust door opening was too small, resulting in incomplete oxygen exhaust, low deoxygenation efficiency, high oxygen content in the feed water, and hidden dangers to boiler production; therefore, in the process of considering the recovery, disposal and reuse of exhaust steam from the deaerator oxygen exhaust door, it is necessary to fully consider the optimal ratio of deoxygenation effect and steam loss. Therefore, a new solution is urgently needed to solve the above technical problems. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a deaerator exhaust door exhaust steam recovery process system, which can selectively introduce the exhaust steam into an air cooling recovery device to eliminate the white pollution caused by the exhaust steam emission to the on-site environment, and recover the exhaust steam condensate to the drain tank and re-enter the deaerator for use, so that the deoxygenation effect reaches the best state to ensure the water quality and ensure the safe and stable operation of the boiler.

[0005] The utility model is realized by the following technical solutions:

[0006] A deaerator exhaust gas steam recovery process system, comprising a deaerator system, the deaerator system comprising a plurality of deaerators distributed in parallel, and an air cooling recovery device, the air cooling recovery device comprising a heat exchange tube bundle, an exhaust gas expansion chamber and a condensate recovery storage chamber;

[0007] The heat exchange tube bundle is transversely arranged in the frame, the inlet end of the heat exchange tube bundle is connected to the exhaust steam diffusion chamber, and the outlet end of the heat exchange tube bundle is connected to the condensate recovery storage chamber;

[0008] The oxygen exhaust door of the deaerator in the deaerator system is connected to an atmospheric exhaust pipe and a recovery pipe respectively, the recovery pipe is connected to the exhaust steam diffusion chamber, and the condensate recovery storage chamber is connected to a drain tank.

[0009] Furthermore, a plurality of cooling fans are provided on the top of the frame, and air outlets of the cooling fans face the heat exchange tube bundle.

[0010] Furthermore, the deaerator system includes a plurality of high-pressure deaerators and low-pressure deaerators.

[0011] Furthermore, the exhaust steam diffusion chamber is a vertical tank body, and the inner wall of the exhaust steam diffusion chamber is provided with a plurality of bell mouths, and the outlet of the recovery pipe is correspondingly connected to the bell mouths.

[0012] Furthermore, an inclinedly distributed convergence plate is provided in the condensate recovery storage chamber, and the convergence plate is located below the outlet end of the heat exchange tube. A drain port is provided at the bottom of the condensate recovery storage chamber, and the drain port is connected to the drain tank through a drain pipe.

[0013] Furthermore, the frame is 10 meters long, 4 meters wide and 6 meters high, and a filter protection cover with a filtration accuracy of 20 mesh is installed around the frame.

[0014] Furthermore, the heat exchange tube bundle is a multi-layer heat exchange tube bundle, each layer of the heat exchange tube bundle comprises a plurality of stainless steel heat exchange tubes, and the outer walls of the stainless steel heat exchange tubes are wound with stainless steel spiral fins.

[0015] Compared with the prior art, the beneficial effects achieved by the utility model are as follows:

[0016] 1. The exhaust steam generated by the deaerator system can be discharged as selected. When the discharge volume is large, it can be selected to enter the air cooling recovery device, and after air cooling, the exhaust steam condensate is formed, and the exhaust steam condensate is recycled into the drain tank;

[0017] According to the change of the deaerator system operating load, the control and regulation door opening is adjusted to ensure the boiler water quality. After the system process is put into operation, the dissolved oxygen in the feed water is measured to stabilize the dissolved oxygen within ≤7ug / l. At the same time, the exhaust steam air cooling recovery device of the exhaust steam of the oxygen exhaust door can recover 5 tons of exhaust steam condensate per hour, which is discharged to the deaerator by the drain pump for repeated use. Based on this calculation, 313 tons of standard coal can be saved each year, and a profit of 438,000 yuan can be achieved;

[0018] 2. When the recovery process system is not activated, the exhaust steam from the front oxygen door is discharged into the atmosphere, which produces a large amount of white steam floating in the air, which has a great impact on the environment, and the steam emission noise is relatively large. After the device is put into use, zero steam emission is achieved, white pollution is eliminated, and the surrounding noise is reduced from 92 decibels to 72 decibels.

[0019] 3. Reuse the recovered exhaust steam condensate to avoid waste of resources and save energy and reduce emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the principle diagram of the exhaust steam recovery process system of the deaerator exhaust door of the utility model;

[0021] Figure 2 This is an internal diagram of the air cooling recovery device of the utility model;

[0022] In the figure: 1. Deaerator system, 2. Heat exchange tube bundle, 3. Exhaust steam expansion chamber, 4. Condensate recovery storage chamber, 5. Cooling fan, 6. Atmospheric discharge pipe, 7. Recovery pipe, 8. Bell mouth, 9. Manifold, 10. Drain tank. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0024] In the description of the utility model, it is necessary to understand that the directions or positional relationships indicated by the terms "front", "rear", "up", "down", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the utility model.

[0025] like Figure 1-2As shown, this embodiment discloses a deaerator exhaust gas recovery process system, including a deaerator system 1 and an air cooling recovery device. The deaerator system 1 includes three high-pressure deaerators and one low-pressure deaerator, and is distributed in parallel. The air cooling recovery device includes a frame, a heat exchange tube bundle 2, a steam expansion chamber 3, and a condensate recovery storage chamber 4. The overall frame structure is designed to be 10 meters long, 4 meters wide, and 6 meters high. The heat exchange tube bundle 2 is arranged horizontally in the frame. In this embodiment, the heat exchange tube bundle 2 is a six-layer heat exchange tube bundle 2, each layer of the heat exchange tube bundle 2 contains 50 stainless steel heat exchange tubes, and the outer wall of the stainless steel heat exchange tube is wrapped with stainless steel spiral fins. In order to improve the heat exchange efficiency, a plurality of three cooling fans 5 are installed on the top of the frame, and the air outlet of the cooling fan 5 faces the heat exchange tube bundle 2. The cooling fan 5 uses an axial flow fan with a power of 15KW and an air volume of 100000m³ / h to achieve forced cooling and improve the heat exchange effect. During normal operation, one cooling fan 5 is opened and two are reserved.

[0026] The exhaust steam diffusion chamber 3 is a vertical tank structure as a whole. Four bellmouths 8 are installed on the inner wall of the exhaust steam diffusion chamber 3. The exhaust doors of the four deaerators in the deaerator system 1 are respectively connected to the atmospheric discharge pipe 6 and the recovery pipe 7. The other end of the recovery pipe 7 corresponds to the bellmouth 8 connected to the exhaust steam diffusion chamber 3. The bellmouth 8 can be effectively used to greatly reduce the exhaust steam flow rate of the exhaust steam of the exhaust door at the outlet position of the bellmouth 8. The flow rate can be reduced from 15m / s to 0.94m / s, which greatly prolongs the heat exchange time of the exhaust steam of the exhaust door in the heat exchange tube bundle 2 and the shell side cold air, so that the exhaust steam can be fully condensed and recovered. The outlet end of the heat exchange tube bundle 2 is connected to the condensate recovery storage chamber 4. In order to facilitate the collection of exhaust steam condensate, an inclined manifold 9 is installed in the condensate recovery storage chamber 4. The manifold 9 is located below the outlet end of the heat exchange tube bundle 2. The bottom of the condensate recovery storage chamber 4 is provided with a drain port near the lower end of the manifold 9. The drain port is connected to the drain tank 10 through a drain pipe.

[0027] The air cooling recovery device described in the utility model is placed at a height of 38 meters on the roof of our company's main factory building, effectively utilizing the advantages of good high-altitude ventilation to maximize the heat exchange effect, and installing a filter protection cover with a filtration accuracy of 20 meshes around the frame. Such a design can effectively prevent floating objects from entering the heat exchange tube bundle 2 and affecting the cooling effect.

[0028] The specific working process of the exhaust steam recovery process system of the deaerator exhaust door of the utility model is as follows:

[0029] The exhaust valve, atmospheric exhaust pipe 6 and recovery pipe 7 of each deaerator in the deaerator system 1 are respectively provided with a switch valve, and whether to collect exhaust steam can be selected according to demand. When the exhaust steam emission is large, the exhaust steam can be selected to enter the exhaust steam expansion chamber 3 through the recovery pipe 7, and then pass through the air cooling recovery device and the air heat exchange cooling to form exhaust steam condensate. The exhaust steam condensate is collected in the condensate recovery storage chamber 4 and then enters the drain tank through the drain pipe. The boiler drain pump drains the exhaust steam condensate in the drain tank to the low-pressure deaerator, realizing the first effective utilization of the exhaust steam condensate recovery. The drain pipe can also be provided with a branch connected to the condensate recovery tank, and a drainage pump is installed for use in the atomization dust suppression of our company's coal conveyor belt corridor, so as to realize the secondary utilization of the exhaust steam condensate and effectively control the dust content within 4mg / m³.

[0030] Through the deaerator exhaust door exhaust steam recovery process system described in the utility model, the door opening is adjusted and controlled according to the change of the operating load of the deaerator system 1 to ensure the quality of boiler water. After the system process is put into operation, the dissolved oxygen in the feed water is measured to stabilize the dissolved oxygen within ≤7ug / l. At the same time, the exhaust steam condensate cooled by the air cooling recovery device of the exhaust steam of the exhaust door can be recovered at 5 tons per hour, and discharged to the deaerator by the drain pump for repeated use. Based on this calculation, 313 tons of standard coal can be saved each year, and a profit of 438,000 yuan can be realized; white pollution is eliminated, and the surrounding noise is reduced from 92 decibels to 72 decibels.

Claims

1. A deaerator exhaust gas steam recovery process system, comprising a deaerator system, wherein the deaerator system comprises a plurality of deaerators distributed in parallel, characterized in that: It also includes an air cooling recovery device, which includes a heat exchange tube bundle, an exhaust steam expansion chamber, and a condensate recovery storage chamber; The heat exchange tube bundle is transversely arranged in the frame, the inlet end of the heat exchange tube bundle is connected to the exhaust steam diffusion chamber, and the outlet end of the heat exchange tube bundle is connected to the condensate recovery storage chamber; The oxygen exhaust door of the deaerator in the deaerator system is connected to an atmospheric exhaust pipe and a recovery pipe respectively, the recovery pipe is connected to the exhaust steam diffusion chamber, and the condensate recovery storage chamber is connected to a drain tank.

2. The exhaust steam recovery process system of the deaerator exhaust door according to claim 1 is characterized in that: A plurality of cooling fans are arranged on the top of the frame, and air outlets of the cooling fans face the heat exchange tube bundle.

3. The exhaust steam recovery process system of the deaerator exhaust door according to claim 1 is characterized in that: The deaerator system includes a plurality of high-pressure deaerators and low-pressure deaerators.

4. The exhaust steam recovery process system of the deaerator exhaust door according to claim 1 is characterized in that: The exhaust steam diffusion chamber is a vertical tank body, and a plurality of bell mouths are arranged on the inner wall of the exhaust steam diffusion chamber, and the outlet of the recovery pipe is correspondingly connected to the bell mouths.

5. The exhaust steam recovery process system of the deaerator exhaust door according to claim 1 is characterized in that: The condensate recovery storage chamber is provided with an inclinedly distributed convergence plate, and the convergence plate is located below the outlet end of the heat exchange tube. The bottom of the condensate recovery storage chamber is provided with a drain port, and the drain port is connected to the drain tank through a drain pipe.

6. The exhaust steam recovery process system of the deaerator exhaust door according to any one of claims 1 to 5, characterized in that: The frame is 10 meters long, 4 meters wide and 6 meters high, and a filter protection cover with a filtering accuracy of 20 mesh is installed around the frame.

7. The exhaust steam recovery process system of the deaerator exhaust door according to any one of claims 1 to 5, characterized in that: The heat exchange tube bundle is a multi-layer heat exchange tube bundle, each layer of the heat exchange tube bundle comprises a plurality of stainless steel heat exchange tubes, and the outer wall of the stainless steel heat exchange tube is wound with stainless steel spiral fins.

Images