Paper machine air hood exhaust treatment system and method

Abstract

The present invention discloses a paper machine hood exhaust treatment system, which includes a deodorizing spray device and a demisting device connected to the hood exhaust port, the demisting device includes a shell with a purification space, a heat exchange module and a mixing water retaining module, the deodorizing spray device is connected to fresh air, the mixing water retaining module is connected to the heat exchange module to separate the purification space into an air inlet chamber and an air exhaust chamber, the air inlet chamber is connected to the deodorizing spray device, the heat exchange module and the mixing water retaining module are both connected to fresh air, and the exhaust chamber is connected to dry hot air. The present invention also provides a paper machine hood exhaust treatment method. The paper machine hood exhaust treatment system and method disclosed by the present invention increase the water saving amount while reducing the temperature and water content of the final exhaust air, add dry hot air to the exhaust chamber to neutralize the humidity of the wet air to increase the dryness of the air, so that the humidity of the air discharged from the exhaust chamber is low, and the demisting and de-whitening effects are improved.

Description

Technical Field

[0001] The invention relates to the technical field of papermaking machinery, and in particular to a paper machine air hood exhaust processing system and method. Background Art

[0002] The largest section in the papermaking process is drying. During the drying process, a large amount of moisture needs to be discharged through closed air hoods, heat recovery, and fans. Due to the high exhaust temperature and high water content, white mist or even fog droplets will be generated when the outdoor temperature is low.

[0003] In the related technology, in order to solve the white mist or dripping mist phenomenon in the papermaking industry, many solutions have emerged: the first is to cool down by spraying cooling water and mixing with cold air; the second is to mix cooling water spraying with heating air (heat recovery preheating plus steam heating); the third is to mix a large amount of cold air. The first and second methods have an additional cooling water system, which occupies a large area, consumes water and electricity, and there is still a small amount of white mist in the cooling tower. The third method has a poor treatment effect, there is a large amount of white mist, and it also occupies a large area. Summary of the invention

[0004] In order to solve the above technical problems, the embodiments of the present invention hope to provide a paper machine hood exhaust treatment system and method with good demisting and de-whitening effects.

[0005] The technical solution of the present invention is achieved in this way:

[0006] A paper machine hood exhaust treatment system comprises a deodorizing spray device connected to the hood exhaust port and a defogger connected to the deodorizing spray device, the defogger comprising a shell having a purification space and a heat exchange module and a mixing water retaining module accommodated in the purification space, fresh air is connected to a spray chamber of the deodorizing spray device, the mixing water retaining module is located above the heat exchange module and is connected to the heat exchange module to divide the purification space into an air inlet chamber and an air exhaust chamber, the air inlet chamber is connected to the deodorizing spray device, the air in the air inlet chamber is subjected to heat exchange, cooling and dehumidification by the heat exchange module, and then enters the mixing water retaining module for mixed dehumidification treatment, and is finally discharged to the exhaust chamber, wherein the heat exchange module and the mixing water retaining module are both subjected to fresh air, and the exhaust chamber is subjected to dry hot air, the hot air is the fresh air heated by the heat exchange module, and the heat source is the waste heat of the exhaust air.

[0007] Preferably, the hybrid water retaining module includes an air inlet window and a water retaining plate connected to the heat exchange module, and a horizontal plate connected to the air inlet window and the water retaining plate. The air inlet window, the water retaining plate and the horizontal plate enclose a water retaining space, and the water retaining space is connected to the atmosphere through the air inlet window.

[0008] Preferably, the air inlet window is an adjustable shutter.

[0009] Preferably, the water baffle is obliquely arranged in the exhaust cavity, and the water baffle includes a plurality of first water baffles and second water baffles arranged at intervals in the shell, one end of the first water baffle and the second water baffle are fixed on the shell, the other ends are overlapped with each other and the ends of the two overlap.

[0010] Preferably, the first water baffle plate and the second water baffle plate are arranged to be inclined with respect to each other, and an angle is formed at the overlap between the two, and the angle is raised toward the top of the shell;

[0011] Wherein, the angle is 90° to 110°.

[0012] Preferably, one end of the first water baffle connected to the shell is bent and extended toward the central axis direction of the shell to form a water guide plate;

[0013] Wherein, the included angle between the water guide plate and the first water baffle plate is 60-90°.

[0014] Preferably, the spray liquid of the deodorizing spray device is a sodium hydroxide solution.

[0015] Preferably, the heat exchange module comprises a heat exchanger and a support plate obliquely arranged below the heat exchanger, the support plates overlap each other and form the air inlet cavity with the shell, and the heat exchanger is obliquely arranged in the shell;

[0016] Wherein, the heat exchanger is an air-to-air plate cross-flow heat exchanger, and the heat exchange plates in the heat exchanger are 304 stainless steel foil.

[0017] A paper machine hood exhaust treatment method comprises the following steps:

[0018] Step S1: connecting the air from the exhaust port of the paper machine hood to the deodorizing spray device, and connecting the spray chamber of the deodorizing spray device to fresh air;

[0019] Step S2: The air in the spray chamber is transported to the air inlet chamber;

[0020] Step S3: the air in the air inlet cavity flows into the heat exchange module for heat exchange, cooling and dehumidification, and the heat exchange module is connected to fresh air;

[0021] Step S4: the air after heat exchange in the heat exchange module enters the mixing water retaining module, and the mixing water retaining module is connected with fresh air;

[0022] Step S5: After water blocking treatment by the mixed water blocking module, the air enters the exhaust chamber, into which dry hot air is connected to eliminate fog and then discharged to the atmosphere. The hot air is fresh air heated by the heat exchange module, and the heat source is the waste heat of the exhaust air.

[0023] Preferably, in step S1, step S3 and step S4, the temperature of the mixed fresh air is -2°C to -7°C, in this example, 15% to 25%, 90% to 140%, and 270% to 360% respectively; and the temperature of the mixed hot air in step S5 is 25°C to 40°C.

[0024] The paper machine hood exhaust treatment system and method provided in the embodiment of the present invention connects fresh air to both the heat exchange module and the mixing water retaining module, and connects dry hot air to the exhaust chamber, so that the fresh air is sent into the heat exchange module to absorb the heat in the saturated hot air and recover the heat. The saturated hot air after cooling and dehumidification enters the mixing water retaining module and mixes with the fresh air to precipitate the condensed water in the wet air, so as to increase the water saving while reducing the temperature and water content of the final exhaust air. Finally, dry hot air is added to the exhaust chamber to neutralize the humidity of the wet air to increase the dryness of the air, so that the humidity of the air discharged from the exhaust chamber is low, thereby effectively improving the demisting and de-whitening effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the structure of the paper machine air hood exhaust processing system provided by the present invention;

[0026] Figure 2 for Figure 1 The structural schematic diagram of the paper machine air hood exhaust treatment system shown;

[0027] Figure 3 for Figure 2 The structural schematic diagram of the demisting device shown;

[0028] Figure 4 for Figure 3 The structural schematic diagram of the water retaining plate shown;

[0029] Figure 5 A flow chart of the paper machine air hood exhaust treatment method provided by the present invention. DETAILED DESCRIPTION

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only 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 making creative work are within the scope of protection of the present invention.

[0031] See also Figure 1 and Figure 2 , Figure 1 A schematic diagram of the structure of the paper machine air hood exhaust processing system provided by the present invention; Figure 2 for Figure 1 The structural schematic diagram of the paper machine hood exhaust treatment system is shown. The paper machine hood exhaust treatment system comprises a deodorizing spray device 3 connected to the hood exhaust port 1 and a demisting device 5 connected to the deodorizing spray device 3. The hood paper machine drying device, the hood exhaust port 1 discharges high temperature air.

[0032] The air discharged from the hood exhaust port 1 enters the spray chamber 31 of the deodorizing spray device 3. The spray liquid sprayed from the spray chamber 31 is spray water mixed with sodium hydroxide solution, which deodorizes and cools the air discharged from the hood exhaust port 1. Fresh air is mixed into the spray chamber 31, so that the hot and humid air reaches a saturated state. The mixed fresh air reduces the amount of water evaporation during the spraying process, and enters the demisting device 5 after mixing. At this time, the relative humidity of the hot and humid air is close to 100%. Among them, the fresh air in the spray chamber 31 is supplied by the fan 33.

[0033] Specifically, the spray chamber 31 is connected to the fan 33, and a humidity detector is arranged in the spray chamber 31. The fresh air volume when the relative humidity of the mixed air reaches 100% is automatically calculated according to the outdoor fresh air state, the exhausted wet air volume and the state point, and the frequency of the fan 33 is controlled according to the calculation result, which is more intelligent.

[0034] See also Figure 3 ,for Figure 2 The structural schematic diagram of the defogger is shown. The defogger 5 comprises a shell 51 having a purification space, and a heat exchange module 53 and a mixing water retaining module 55 housed in the purification space, wherein the mixing water retaining module 55 is located above the heat exchange module 53 and connected to the heat exchange module 53 to separate the purification space into an air inlet chamber 57 and an air exhaust chamber 59, wherein the air inlet chamber 57 is connected to the spray chamber 31 of the deodorizing spray device 3, and the air in the air inlet chamber 57 is cooled and dehumidified by the heat exchange module 53, and then enters the mixing water retaining module 55 for mixing and dehumidification, and then enters the exhaust chamber 59, wherein the heat exchange module 53 and the mixing water retaining module 55 are both connected to fresh air, and the exhaust chamber 59 is connected to dry hot air. In this way, by connecting fresh air to both the heat exchange module 53 and the mixing water retaining module 55, and connecting dry hot air to the exhaust chamber 59, the fresh air is sent into the heat exchange module 53 to absorb the heat in the saturated hot air, and heat is recovered. The saturated hot air after cooling and dehumidification enters the mixing water retaining module 55 and mixes with the fresh air to precipitate the condensed water in the wet air, thereby increasing the water saving amount and reducing the water content of the final exhaust air. Finally, dry hot air is added to the exhaust chamber 59 to neutralize the humidity of the wet air to increase the dryness of the air, so that the humidity of the air discharged from the exhaust chamber 59 is low, thereby achieving the purpose of defogger and de-whitening.

[0035] The hot air introduced into the exhaust chamber is fresh air heated by the heat exchange module, and the heat source is the waste heat of the exhaust air, so that the heat can be reused and resources can be effectively saved.

[0036] An exhaust fan 52 is disposed on the top of the housing 51 , and the exhaust fan 52 is controlled by frequency conversion to achieve control of exhaust air volume.

[0037] The mixed water retaining module 55 includes an air inlet window 551 and a water retaining plate 553 connected to the heat exchanger 531, and a transverse plate 555 connected to the air inlet window 551 and the water retaining plate 553. The air inlet window 551, the water retaining plate 553 and the transverse plate 555 enclose a water retaining space 557, and the water retaining space 557 is connected to the atmosphere through the air inlet window 551 to precipitate condensed water in the humid air. The heat exchanger is tilted, and the angle between it and the central axis of the shell is 30°.

[0038] Specifically, the water baffle 553 is tiltedly arranged in the exhaust cavity 59, so that the water baffle 553 has a larger water baffle area and a better water baffle effect. The structure of the demisting device 5 is optimized to minimize the air resistance and volume of the system, thereby achieving the purpose of energy saving and consumption reduction and reducing the occupied area.

[0039] The air inlet window 551 is an adjustable shutter, and fresh air enters the water retaining space 557 from the shutter. The opening and closing and angle of the air inlet window 551 can be adjusted manually or automatically.

[0040] See also Figure 4 ,for Figure 3 The structural schematic diagram of the water baffle is shown. The water baffle 553 includes a plurality of first water baffles 558 and second water baffles 559 spaced apart in the shell 51, one end of each of the first water baffle 558 and the second water baffle 559 is fixed to the shell 51, and the other ends are overlapped with each other and the ends of the two overlap to form a closed water-blocking area, and the water baffle 553 is provided with air holes, and the air after water blocking is discharged from the air holes into the exhaust cavity 59.

[0041] The first water baffle plate 558 and the second water baffle plate 559 are arranged at an angle, and the overlap between the two forms an angle A, and the angle A protrudes toward the top of the shell 51, so that the steam and water in the air flow down along the side wall from the angle A between the first water baffle plate 558 and the second water baffle plate 559.

[0042] The angle A is between 90° and 110°, that is, the angle A can be 90°, 100° or 110°. Preferably, in this embodiment, the angle A is 90°.

[0043] One end of the first water baffle 558 connected to the housing 51 is bent and extended to form a water guide plate 560 in the direction of the central axis of the housing 51. In this way, water flowing down from the top of the first water baffle 558 and the second water baffle 559 can flow out from the water guide plate 560 without flowing out of the housing 51.

[0044] The angle B between the water guide plate 560 and the first water baffle plate 558 is 60-90°. That is, the angle B between the water guide plate 560 and the first water baffle plate 558 can be 60°, 70°, 75°, 80° or 90°. Preferably, in this embodiment, the angle B between the water guide plate 560 and the first water baffle plate 558 is 75°.

[0045] The heat exchange module 53 includes a heat exchanger 531 and a support plate 533 obliquely arranged below the heat exchanger 531. The support plates 533 are overlapped with each other and form the air inlet chamber 57 with the shell 51. The heat exchanger 531 is obliquely arranged in the shell 51, so that the hot air in the air inlet chamber 57 can quickly enter from the cold side of the heat exchanger 531, thereby improving work efficiency.

[0046] Specifically, in this embodiment, the heat exchanger 531 is an air-to-air plate cross-flow heat exchanger, and the heat exchange plates in the heat exchanger are 304 stainless steel foil.

[0047] See also Figure 5 , is a flow chart of the paper machine air hood exhaust treatment method provided by the present invention. The paper machine air hood exhaust treatment method comprises the following steps:

[0048] Step S1: connect the air from the paper machine hood exhaust port 1 to the deodorizing spray device 3, the spray chamber 31 of the deodorizing spray device 3 is connected to the outside, connect the fresh air to the spray chamber 31 to penetrate the fresh air into the spray chamber 31 to form the first mixing of hot air, and the mixed hot air reaches a saturated state with a humidity of 100%. Specifically, the fresh air mixed at this time is 15-25% in this example, and preferably, in this embodiment, the temperature of the fresh air is -3°C.

[0049] Step S2: introducing the saturated hot air in the spray chamber 31 into the air inlet chamber 57 .

[0050] Step S3: the saturated hot air in the air inlet cavity 57 is discharged into the heat exchanger of the heat exchange module 53 for heat exchange and cooling. The cold side of the heat exchanger of the heat exchange module is connected to fresh air, and the fresh air mixed in this example is 90-140%.

[0051] Step S4: The humid air after heat exchange, cooling and dehumidification by the heat exchange module 53 enters the water retaining space 557 of the mixing water retaining module 55 to precipitate condensed water, and the mixing water retaining module 55 is connected with fresh air to mix with the humid air to form a second mixing. Specifically, the fresh air mixed in this example is 270-360%, and preferably, in this embodiment, the temperature of the fresh air is -3°C.

[0052] Step S5: After the water blocking treatment by the mixing water blocking module 55, the air enters the exhaust chamber 59, and the exhaust chamber 59 is connected with dry hot air to eliminate the fog and then discharged to the atmosphere. The dry hot air is mixed with the hot air entering the exhaust chamber 59 for the second time. At this time, the temperature of the mixed hot air is 25°C to 40°C. Preferably, in this embodiment, the temperature of the dry hot air is 35°C. The purpose of demisting and whitening is achieved through the first mixing, the second mixing and the third mixing.

[0053] It should be noted that the air inlet chamber 57, the exhaust chamber 59 and the water retaining space 557 are all provided with a thermometer and a hygrometer, and the thermometer and the hygrometer are connected to the fan and the exhaust fan, and are automatically adjusted and frequency-controlled according to the data detected of the temperature and humidity at each stage, so that the entire system can automatically adjust according to different working conditions and operate intelligently.

[0054] The paper machine hood exhaust treatment system and method provided in the embodiment of the present invention connects fresh air to both the heat exchange module and the mixing water retaining module, and connects dry hot air to the exhaust chamber, so that the fresh air is sent into the heat exchange module to absorb the heat in the saturated hot air and recover the heat. The saturated hot air after cooling and dehumidification enters the mixing water retaining module and mixes with the fresh air to precipitate the condensed water in the wet air, so as to increase the water saving while reducing the temperature and water content of the final exhaust air. Finally, dry hot air is added to the exhaust chamber to neutralize the humidity of the wet air to increase the dryness of the air, so that the humidity of the air discharged from the exhaust chamber is low, thereby effectively improving the demisting and de-whitening effects.

[0055] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A paper machine hood exhaust treatment method, characterized in that: The steps include: Step S1: connecting the air from the exhaust port of the paper machine hood to the deodorizing spray device, and connecting the spray chamber of the deodorizing spray device to fresh air; Step S2: The air in the spray chamber is transported to the air inlet chamber; Step S3: the air in the air inlet cavity flows into the heat exchange module for heat exchange, cooling and dehumidification, and the heat exchange module is connected to fresh air; Step S4: the air after heat exchange in the heat exchange module enters the mixing water retaining module, and the mixing water retaining module is connected with fresh air; Step S5: After water blocking treatment by the mixed water blocking module, the air enters the exhaust chamber, into which dry hot air is connected to eliminate fog and then discharged to the atmosphere. The hot air is fresh air heated by the heat exchange module, and the heat source is the waste heat of the exhaust air.

2. The paper machine hood exhaust treatment method according to claim 1, characterized in that: In step S1, step S3 and step S4, the temperature of the mixed fresh air is -2°C to -7°C, and the proportions are 15-25%, 90-140%, and 270-360% respectively; in step S5, the temperature of the mixed hot air is 25°C to 40°C.

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