Multi-layer demisting flash evaporator

Abstract

The multi-layer demisting flash evaporator of the present invention relates to a flash evaporator with multiple demisters inside, aiming to overcome the problems of insufficient flashing amount of the existing flash evaporator and poor demisting effect of the demister. The Nth-stage demisting device includes a demisting plate; except for the Nth-stage demisting device, other stages of demisting devices each include a demisting plate and a fog and vapor baffle; the 1st-stage demisting plate to the Nth-stage demisting plate are horizontally fixed in the flash evaporator tank from top to bottom in sequence, and the demisting plates of adjacent two-stage demisting devices are hermetically connected through the corresponding fog and vapor baffles; the fog and vapor input surfaces of each demisting plate are all located on the side of the fog and vapor channel, and the bottom end of the fog and vapor channel is communicated with the flash chamber inside the flash evaporator tank, and the top end is the fog and vapor input surface of the 1st-stage demisting plate; the dry vapor output surfaces of each demisting plate are all located on the side of the dry vapor channel, and the top end of the dry vapor channel is communicated with the flash vapor outlet on the side wall of the flash evaporator tank, and the bottom end is the dry vapor output surface of the Nth-stage demisting plate.

Description

Technical Field

[0001] The present invention relates to a flash evaporator with multiple layers of demisters inside. Background Art

[0002] In various industrial production processes such as metallurgy, coal chemical industry, and salt chemical industry, there are a large amount of medium and low temperature process circulating cooling water or process wastewater. Most of the industrial process circulating cooling water or process wastewater is contaminated wastewater with corrosiveness, easy deposition, and easy scaling. On the one hand, due to its large circulation volume and stable temperature characteristics, the wastewater contains a huge amount of heat. On the other hand, due to the complex water quality components and high dissolved salt content, it is difficult to recover heat energy and treat water, resulting in a large amount of industrial waste heat being wasted in vain. At the same time, if the wastewater cannot be properly treated, it may cause serious environmental pollution.

[0003] The currently relatively ideal method for recovering waste heat from such wastewater is the "vacuum phase change flash evaporation heat exchange" method. This method artificially creates a negative pressure environment, causing medium and low temperature wastewater to flash in the negative pressure environment. The clean steam after flashing enters the subsequent heat exchange unit (such as a direct heat engine condenser, an absorption heat pump evaporator, etc.) to condense and release heat, thereby realizing the recovery of waste heat and flash condensation water in the wastewater. The above-mentioned "negative pressure environment" is generally a closed tank body, which is called a flash evaporator.

[0004] However, the above-mentioned negative pressure flash evaporator is not equipped with a demisting device or is only equipped with a single-layer demisting device. The flash evaporator without a demisting device needs to be equipped with a demisting tank separately, and the inside of the demisting tank is also only in a single-layer demisting form. Due to the influence of equipment cost and floor area, the cross-sectional size of the existing flash evaporator and the equipped demisting device is limited. Furthermore, the area of the assembled single-layer demisting device is also limited, resulting in too fast a flow velocity of the flash steam through the demisting device, thus causing the following problems:

[0005] 1. Increase the resistance of the flash steam flowing through the demisting device, affect the steam throughput, cause insufficient flashing amount of the flash evaporator, and affect the waste heat recovery and wastewater treatment volume;

[0006] 2. Too high a steam flow velocity is likely to cause the phenomenon of secondary steam water carrying, resulting in a poor demisting effect of the demisting device, thus polluting the subsequent heat exchange unit and causing problems such as poor quality of steam condensate water. Summary of the Invention

[0007] The purpose of the present invention is to overcome the problems of insufficient flashing amount of the existing flash evaporator and poor demisting effect of the demister, and provide a multi-layer demisting flash evaporator.

[0008] The multi-layer demisting flash evaporator of the present invention includes a demisting unit and a flash evaporator tank body;

[0009] The demisting unit includes a first-stage demisting device to an N-stage demisting device, and N is an integer greater than 1;

[0010] The Nth - stage demister device includes a demister plate; except for the Nth - stage demister device, other stages of demister devices each include a demister plate and a mist - vapor baffle;

[0011] The 1st - stage demister plate to the Nth - stage demister plate are horizontally fixed in the flash - evaporator tank from top to bottom in sequence. The demister plates between adjacent two - stage demister devices are hermetically connected through corresponding mist - vapor baffles, so that the demister unit divides the demisting area into a mist - vapor channel and a dry - vapor channel; the demisting area is the area in the flash - evaporator tank where the demister unit is arranged; the 1st - stage demister plate to the Nth - stage demister plate are respectively the demister plates in the 1st - stage demister device to the Nth - stage demister device;

[0012] Moreover, the mist - vapor input surface of each demister plate is located on the side of the mist - vapor channel, and the bottom end of the mist - vapor channel is communicated with the flash chamber inside the flash - evaporator tank, and the top end is the mist - vapor input surface of the 1st - stage demister plate;

[0013] The dry - vapor output surface of each demister plate is located on the side of the dry - vapor channel, and the top end of the dry - vapor channel is communicated with the flash - vapor outlet on the side wall of the flash - evaporator tank, and the bottom end is the dry - vapor output surface of the Nth - stage demister plate.

[0014] The beneficial effects of the present invention are as follows:

[0015] The present invention provides a multi - layer demisting flash - evaporator, which solves the problem of insufficient area of the demister device equipped in the traditional flash - evaporator, realizes that a larger - area demister device can be equipped under the premise of the same cross - sectional area of the tank body and floor area, reduces the flow - through speed of the steam passing through the demister device, thereby increasing the flash evaporation capacity of the flash - evaporator, increasing the waste heat recovery and the wastewater treatment volume; and reducing or eliminating the phenomenon of steam carrying water twice, improving the demisting effect of the demister device, preventing the pollution of the subsequent heat - exchange unit and improving the water quality of the steam condensate. Brief Description of the Drawings

[0016] Figure 1 It is the front - view sectional structure schematic diagram of the multi - layer demisting flash - evaporator of the present invention;

[0017] Figure 2 It is the side - view sectional structure schematic diagram of the multi - layer demisting flash - evaporator of the present invention;

[0018] Figure 3 It is the matching structure schematic diagram of the 1st - stage demister plate and the flash - evaporator tank in the multi - layer demisting flash - evaporator of the present invention when N = 3;

[0019] Figure 4 It is the matching structure schematic diagram of the 2nd - stage demister plate and the flash - evaporator tank in the multi - layer demisting flash - evaporator of the present invention when N = 3;

[0020] Figure 5In the multi-layer demisting flash evaporator of the present invention, when N = 3, it is a schematic diagram of the matching structure between the third-stage demisting plate and the flash evaporator tank body. Detailed implementation mode

[0021] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work belong to the scope of protection of the present invention.

[0022] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0023] Next, the present invention will be further described in conjunction with the accompanying drawings and specific embodiments, but it is not limited to the present invention.

[0024] Detailed implementation mode one, the multi-layer demisting flash evaporator of this implementation mode includes a demisting unit and a flash evaporator tank body;

[0025] The demisting unit includes a first-stage demisting device to an Nth-stage demisting device, and N is an integer greater than 1;

[0026] The Nth-stage demisting device includes a demisting plate; except for the Nth-stage demisting device, other stages of demisting devices each include a demisting plate and a mist-vapor baffle;

[0027] The first-stage demisting plate to the Nth-stage demisting plate are horizontally fixed in the flash evaporator tank body from top to bottom in sequence. The demisting plates of adjacent two-stage demisting devices are hermetically connected through corresponding mist-vapor baffles, so that the demisting unit divides the demisting area into a mist-vapor channel 3 and a dry-vapor channel 4; the demisting area is the area in the flash evaporator tank body where the demisting unit is arranged; the first-stage demisting plate to the Nth-stage demisting plate are respectively the demisting plates in the first-stage demisting device to the Nth-stage demisting device;

[0028] Moreover, the mist-vapor input surfaces of each demisting plate are all located on the side of the mist-vapor channel 3, and the bottom end of the mist-vapor channel 3 is communicated with the flash chamber inside the flash evaporator tank body, and the top end is the mist-vapor input surface of the first-stage demisting plate;

[0029] The dry-vapor output surfaces of each demisting plate are all located on the side of the dry-vapor channel 4, and the top end of the dry-vapor channel 4 is communicated with the flash vapor outlet on the side wall of the flash evaporator tank body, and the bottom end is the dry-vapor output surface of the Nth-stage demisting plate.

[0030] Among them, the Nth-stage demisting device is a baffle demister, a wire mesh demister or a spiral demister.

[0031] Among them, when N = 2,

[0032] There is a gap between the outer sidewall of the first-stage demisting plate and the inner sidewall of the flash evaporator tank body; there is a gap between the outer sidewall of the second-stage demisting plate and the inner sidewall of the flash evaporator tank body; the two gaps are staggered from each other;

[0033] One end of the first-stage mist baffle is sealingly connected to the outer sidewall of the first-stage demisting plate at the gap, and the other end is sealingly connected to the outer sidewall of the second-stage demisting plate at the gap; and both sides of the first-stage mist baffle are sealingly connected to the inner sidewall of the flash evaporator tank body; so that the mist input surface of the second-stage demisting plate, one side of the first-stage mist baffle, the mist input surface of the first-stage demisting plate and the corresponding inner sidewall of the flash evaporator tank body enclose to form a mist channel 3; and so that the dry steam output surface of the second-stage demisting plate, the other side of the first-stage mist baffle, the dry steam output surface of the first-stage demisting plate and the corresponding inner sidewall of the flash evaporator tank body enclose to form a dry steam channel 4;

[0034] The first-stage mist baffle 1-1-2 to the second-stage mist baffle are the demisting plates in the first-stage demisting device to the second-stage demisting device respectively.

[0035] Wherein, when N≥3,

[0036] There is a gap between the outer sidewall of the first-stage demisting plate and the inner sidewall of the flash evaporator tank body; there are two gaps between the outer sidewalls on both sides of the second-stage demisting plate to the (N-1)-th stage demisting plate and the inner sidewall of the flash evaporator tank body respectively; there is a gap between the outer sidewall of the N-th stage demisting plate and the inner sidewall of the flash evaporator tank body; the gaps corresponding to adjacent two-stage demisting plates are staggered;

[0037] One end of the first-stage mist baffle is sealingly connected to the outer sidewall of the first-stage demisting plate at the corresponding gap;

[0038] The other end of the (N-1)-th stage mist baffle is sealingly connected to the outer sidewall of the N-th stage demisting plate at the corresponding gap;

[0039] One end of the second-stage demisting plate to the (N-1)-th stage demisting plate is sealingly connected to one end of the same-stage demisting plate at the corresponding gap respectively; and the other end of the second-stage demisting plate to the (N-1)-th stage demisting plate is sealingly connected to the other end of the previous-stage demisting plate at the corresponding gap respectively;

[0040] Both sides of the first-stage mist baffle to the N-th stage mist baffle are sealingly connected to the inner sidewall of the flash evaporator tank body; so that the mist input surfaces of the N-th stage demisting plate to the first-stage demisting plate, one side of the (N-1)-th stage mist baffle to the first-stage mist baffle and the corresponding inner sidewall of the flash evaporator tank body enclose to form a mist channel 3; and so that the dry steam output surfaces of the N-th stage demisting plate to the first-stage demisting plate, the other side of the (N-1)-th stage mist baffle to the first-stage mist baffle and the corresponding inner sidewall of the flash evaporator tank body enclose to form a dry steam channel 4;

[0041] The 1st-stage mist baffle 1-1-2 to the Nth-stage mist baffle are the demisting plates in the 1st-stage to the Nth-stage demisting devices respectively.

[0042] Among them, the 1st-stage to the Nth-stage demisting plates are spiral demisting plates.

[0043] Specifically, as Figures 1 to 5 shown, it is the schematic diagram of the main view sectional structure of the multi-stage demisting flash evaporator of this embodiment. The outer shape of the multi-stage demisting flash evaporator is a vertical tank body, and its interior includes the upper three-stage demisting devices, the lower wastewater flash device and the inlets and outlets of various media.

[0044] The flash steam tank body 2 of the multi-stage demisting flash evaporator is mainly composed of an upper head 2-1, a cylinder body 2-2, a lower head 2-3, a wastewater inlet 2-4, a wastewater discharge port 2-5 and a flash steam outlet 2-6. The wastewater inlet 2-4 is arranged on the outer side wall of the cylinder body 2-2, and a water accumulation chamber 2-9 is arranged above the lower head 2-3. The bottom of the lower head 2-3 is externally connected to the wastewater discharge port 2-5. In the lower part inside the multi-stage demisting flash evaporator, below the 3rd-stage demisting device, a splash droplet baffle 2-7 and a flash chamber 2-8 are successively arranged.

[0045] Taking N = 3 as an example, at the highest position near the upper head 2-1 inside the multi-stage demisting flash evaporator, the 1st-stage demisting device is arranged, and the 1st-stage demisting device includes: the 1st-stage demisting plate 1-1-1 and the 1st-stage mist baffle 1-1-2.

[0046] The 1st-stage demisting plate 1-1-1 (a spiral demisting plate can be selected) is horizontally arranged. The 1st-stage demisting plate 1-1-1 is a large semi-circular flat plate (a sector column with a cross-section of a major arc sector) with a straight notch (the gap between it and the inner side wall of the flash steam tank body 2), and the diameter of the major arc sector is equal to the inner diameter of the cylinder body 2-2. The flash steam containing water droplets becomes dry steam after removing the contained water droplets through the 1st-stage demisting plate 1-1-1 and flows into the dry steam channel 4 from the mist channel 3.

[0047] The 1st-stage mist baffle 1-1-2 is a folding plate, which is connected from the edge of the straight notch of the 1st-stage demisting plate 1-1-1 to the edge of the straight notch on the mist side of the 2nd-stage demisting plate 1-2-1. The 1st-stage mist baffle 1-1-2 is the partition wall between the mist channel 3 and the dry steam channel 4, and its function is to isolate the mist from the dehydrated and demisted dry steam between the 1st-stage demisting plate 1-1-1 and the 2nd-stage demisting plate 1-2-1.

[0048] In the middle part inside the multi-stage demisting flash evaporator, below the 1st-stage demisting device, the 2nd-stage demisting device is arranged, and the 2nd-stage demisting device includes: the 2nd-stage demisting plate 1-2-1 and the 2nd-stage mist baffle 1-2-2.

[0049] The second-stage demisting plate 1-2-1 is horizontally arranged. The second-stage demisting plate 1-2-1 is a waist-drum-shaped flat plate with straight notches on both the left and right sides. The diameter of the waist-drum circle is equal to the inner diameter of the cylinder 2-2. The flashing steam containing water droplets passes through the second-stage demisting plate 1-2-1 and then removes the contained water droplets to become dry steam, and flows into the dry steam channel 4 from the mist steam channel 3.

[0050] The second-stage mist steam baffle 1-2-2 is a folded plate, which is connected from the edge of the straight notch on the dry steam side of the second-stage demisting plate 1-2-1 to the edge of the straight notch on the mist steam side of the third-stage demisting plate 1-3-1. Its function is to isolate the mist steam from the dry steam that has been dehydrated and demisted between the second-stage demisting plate 1-2-1 and the third-stage demisting plate 1-3-1.

[0051] In the middle and lower part of the multi-stage demisting flash evaporator, below the second-stage demisting device, a third-stage demisting device is arranged. The structure of the third-stage demisting device includes: the third-stage demisting plate 1-3-1.

[0052] The third-stage demisting plate 1-3-1 is horizontally arranged. The third-stage demisting plate 1-3-1 is a large semi-circular flat plate with a straight notch. The diameter of the flat plate circle is equal to the inner diameter of the cylinder 2-2. The flashing steam containing water droplets passes through the third-stage demisting plate 1-3-1 and then removes the contained water droplets to become dry steam, and flows into the dry steam channel 4 from the mist steam channel.

[0053] The working principle of the multi-stage demisting flash evaporator is as follows:

[0054] 1. Industrial waste hot water enters the flash chamber 2-8 from the waste water inlet 2-4 of the multi-stage demisting flash evaporator. Since the pressure in the flash chamber 2-8 is lower than the saturation pressure corresponding to the temperature of the waste hot water, the waste hot water immediately flashes. The generated flashing steam flows upward, and the flashed remaining water drips downward into the water accumulation chamber 2-9. The waste water entering the flash chamber impacts the bottom and the splashing droplets generated during the flashing process are blocked by the splashing droplet baffle 2-7 to prevent splashing onto the demisting unit.

[0055] 2. A part of the steam flowing upward passes through the third-stage demisting plate 1-3-1. The third-stage demisting plate 1-3-1 is composed of a number of vertical spiral channels. Relying on the centrifugal force, the water droplets contained in the mist steam are removed to become dry steam, and the water droplets in the steam are removed to become dry steam and enter the dry steam channel 4; another part of the steam containing water enters the mist steam channel 3.

[0056] 3. The steam containing water entering the mist steam channel 3 flows upward along the space between the second-stage mist steam baffle 1-2-2 and the inner wall of the cylinder 2-2. A part of it passes through the second-stage demisting plate 1-2-1, removes the water droplets in the steam, becomes dry steam and enters the dry steam channel 4, and the separated water droplets flow downward along the second-stage mist steam baffle 1-2-2; another part of the steam containing water continues to flow upward along the mist steam channel 3.

[0057] 4. The steam entering the steam channel 3 flows upward along the space between the first-stage steam baffle 1-1-2 and the inner wall of the cylinder body 2-2, passes through the first-stage demisting plate 1-1-1, removes the water droplets in the steam, becomes dry steam and enters the dry steam channel 4, while the separated water droplets flow downward along the first-stage steam baffle 1-1-2;

[0058] 5. The water-free dry steam entering the dry steam channel 4 through the demisting unit flows out from the flash steam outlet 2-6 at the upper part of the outer side wall of the cylinder body 2-2 and is transported outward to the steam-using equipment.

[0059] 6. The water accumulation chamber 2-9 on the lower head 2-3 collects the water droplets separated by the demisting unit and the remaining waste water from the flash evaporation of the waste hot water entering the cylinder body 2-2, and then discharges through the waste water discharge port 2-5 at the bottom of the lower head by means of an external drainage pump.

[0060] Moreover, the multi-stage demisting plates configured in the multi-layer demisting and flash evaporator can also be composed of any form of demisting device such as a baffle demister and a wire mesh demister.

[0061] In the best embodiment, the number of demisting unit layers configured in the multi-layer demisting and flash evaporator can be 1 to N layers. The structural form of the demisting plate of the lowermost layer (the Nth layer) is the same as that of the third-stage demisting plate in Embodiment 1. The first demisting plate is the uppermost demisting plate, and its structural form is the same as that of the first-stage demisting plate in Embodiment 1. The demisting plates of the 2nd to N-1th layers are arranged between the first-stage demisting plate and the Nth-stage demisting plate, and the structural form is the same as that of the second-stage demisting plate in Embodiment 1.

[0062] Although the present invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed, as long as they do not deviate from the spirit and scope of the present invention defined by the appended claims. It should be understood that different dependent claims and the features described herein can be combined in a manner different from that described in the original claims. It should also be understood that the features described in connection with a single embodiment can be used in other described embodiments.

Claims

1. Multi-layer demisting flash evaporator, characterized in that, It includes a demisting unit and a flash tank body; The demisting unit includes a first-stage demisting device to an N-stage demisting device, and N is an integer greater than 1; The N-stage demisting device includes a demisting plate; except for the N-stage demisting device, other stages of demisting devices each include a demisting plate and a mist and vapor baffle; The first-stage demisting plate (1-1-1) to the N-stage demisting plate are horizontally fixed in the flash tank body from top to bottom in sequence. The demisting plates of adjacent two-stage demisting devices are hermetically connected through corresponding mist and vapor baffles, so that the demisting unit divides the demisting area into a mist and vapor channel (3) and a dry vapor channel (4); the demisting area is the area in the flash tank body where the demisting unit is arranged; the first-stage demisting plate (1-1-1) to the N-stage demisting plate are respectively the demisting plates in the first-stage demisting device to the N-stage demisting device; Moreover, the mist and vapor input surfaces of each demisting plate are all located on the side of the mist and vapor channel (3), and the bottom end of the mist and vapor channel (3) communicates with the flash chamber (2-8) inside the flash tank body, and the top end is the mist and vapor input surface of the first-stage demisting plate (1-1-1); The dry vapor output surfaces of each demisting plate are all located on the side of the dry vapor channel (4), and the top end of the dry vapor channel (4) communicates with the flash vapor outlet (2-6) on the side wall of the flash tank body, and the bottom end is the dry vapor output surface of the N-stage demisting plate; The first-stage demisting plate (1-1-1) to the N-1 demisting plate are spiral demisting plates; The N-stage demisting device is a baffle demister or a wire mesh demister.

2. The multi-layer demisting flash evaporator according to claim 1, wherein When N = 2, There is a gap between the outer side wall of the first-stage demisting plate (1-1-1) and the inner side wall of the flash tank body; there is a gap between the outer side wall of the second-stage demisting plate and the inner side wall of the flash tank body; the two gaps are staggered from each other; One end of the first-stage mist and vapor baffle (1-1-2) is hermetically connected to the outer side wall of the first-stage demisting plate (1-1-1) at the gap, and the other end is hermetically connected to the outer side wall of the second-stage demisting plate at the gap; and both sides of the first-stage mist and vapor baffle (1-1-2) are hermetically connected to the inner side wall of the flash tank body; so that the mist and vapor input surface of the second-stage demisting plate, one side of the first-stage mist and vapor baffle (1-1-2), the mist and vapor input surface of the first-stage demisting plate (1-1-1) and the corresponding inner side wall of the flash tank body enclose to form the mist and vapor channel (3); and so that the dry vapor output surface of the second-stage demisting plate, the other side of the first-stage mist and vapor baffle (1-1-2), the dry vapor output surface of the first-stage demisting plate (1-1-1) and the corresponding inner side wall of the flash tank body enclose to form the dry vapor channel (4); The first-stage mist and vapor baffle (1-1-2) to the second-stage mist and vapor baffle are respectively the mist and vapor baffles in the first-stage demisting device to the second-stage demisting device.

3. The multi-layer demisting flash evaporator according to claim 1, wherein When N≥3, There is a gap between the outer side wall of the first-stage demisting plate (1-1-1) and the inner side wall of the flash tank body; there are two gaps between the outer side walls on both sides of the second-stage demisting plate to the N-1-stage demisting plate and the inner side wall of the flash tank body respectively; there is a gap between the outer side wall of the N-stage demisting plate and the inner side wall of the flash tank body; the gaps corresponding to adjacent two-stage demisting plates are staggered; One end of the first-stage mist baffle (1-1-2) is hermetically connected to the outer sidewall of the first-stage demisting plate (1-1-1) at the corresponding gap; The other end of the (N-1)-th stage mist baffle is hermetically connected to the outer sidewall of the N-th stage demisting plate at the corresponding gap; One end of the second-stage to (N-1)-th stage demisting plates is hermetically connected to one end of the demisting plates of the same stage at the corresponding gaps respectively; and the other end of the second-stage to (N-1)-th stage demisting plates is hermetically connected to the other end of the demisting plate of the previous stage at the corresponding gaps respectively; Both sides of the first-stage mist baffle (1-1-2) to the N-th stage mist baffle are hermetically connected to the inner sidewall of the flash tank body; so that the mist input surfaces of the N-th stage demisting plate to the first-stage demisting plate (1-1-1), one side of the (N-1)-th stage mist baffle to the first-stage mist baffle (1-1-2), and the corresponding inner sidewall of the flash tank body surround to form a mist channel (3); and so that the dry steam output surfaces of the N-th stage demisting plate to the first-stage demisting plate (1-1-1), the other side of the (N-1)-th stage mist baffle to the first-stage mist baffle (1-1-2), and the corresponding inner sidewall of the flash tank body surround to form a dry steam channel (4); The first-stage mist baffle (1-1-2) to the (N-1)-th stage mist baffle are the mist baffles in the first-stage demisting device to the (N-1)-th stage demisting device respectively.

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