Wastewater evaporation heat exchanger structure

Abstract

The utility model relates to wastewater treatment technical field, concretely discloses a wastewater evaporation heat exchanger structure, including first heat exchange unit, second heat exchange unit and vacuum pump, first heat exchange unit contains first cylinder and first heat exchange body inside, second heat exchange unit contains second cylinder and second heat exchange body inside, and vacuum pump is vacuum compression pump, can drive water vapor and circulate between second heat exchange unit, first heat exchange unit and itself, and first water outlet is connected with second water inlet, second exhaust port is connected with first air inlet. The structure reduces energy consumption through steam recycling, reduces the influence of impurity deposition on heat exchange efficiency by virtue of the anti-fouling characteristics of the spiral pipe and the gap design of the fixed plate, to solve the problem of high processing cost and insufficient stability in the prior art caused by high energy consumption and heat exchange efficiency affected by impurities, realize the balance of energy consumption and efficiency, and meet the demand of industry for wastewater treatment continuity and stability.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment technology, and in particular to a wastewater evaporative heat exchanger structure. Background Technology

[0002] In the industrial electrolytic production of sodium hypochlorite and sodium chlorate, the heat exchanger, as a key temperature control device, directly affects electrolysis efficiency, product stability, and energy utilization efficiency. Sodium hypochlorite electrolysis requires a low-temperature environment (typically 20-40℃) because high temperatures cause hypochlorite ions (ClO-) to undergo a disproportionation reaction, generating chlorate impurities and reducing the purity of the target product. Conversely, sodium chlorate electrolysis requires maintaining a high-temperature environment of 70-90℃ to promote the conversion of hypochlorite ions to chlorate ions (ClO3-). - The conversion of electrolytes accelerates the reaction process. The different temperature requirements of the two processes necessitate that the electrolysis system be equipped with efficient heat exchange equipment to precisely control the electrolyte temperature.

[0003] During electrolysis, the electrode reactions are accompanied by a significant exothermic effect, causing the electrolyte temperature to rise continuously. If not intervened in time, the sodium hypochlorite system will experience product degradation due to overheating, while the sodium chlorate system may experience exacerbated side reactions (such as chlorine gas escape) or electrode corrosion due to excessively high local temperatures. Simultaneously, the high-temperature wastewater (40-80℃) discharged from the electrolytic cell carries a large amount of waste heat. Direct discharge not only wastes energy but also impacts subsequent wastewater treatment systems due to the high temperature (such as inhibiting microbial activity). Therefore, the heat exchanger must perform a dual core function: firstly, by exchanging heat with the electrolyte, it stabilizes the sodium hypochlorite electrolysis temperature within a low-temperature range or maintains the sodium chlorate electrolysis temperature within a high-temperature range; secondly, it recovers the waste heat from the electrolysis wastewater for preheating the raw material brine and heating the reaction medium, achieving energy conservation and consumption reduction.

[0004] For example, in patent "CN201920668571, Heat Exchanger for Wastewater Flash Evaporation System," while traditional shell-and-tube heat exchangers offer certain heat exchange advantages, they are prone to scaling and clogging when treating pharmaceutical wastewater due to the high impurity content, severely impacting treatment efficiency and effectiveness. This patent addresses the scaling problem by employing a specific plate heat exchanger structure. However, it still has limitations in the industrial electrolytic production of sodium hypochlorite and sodium chlorate. For instance, it cannot effectively meet the high energy consumption demands of industrial electrolytic production of sodium hypochlorite and sodium chlorate, and its heat exchange efficiency and stability are difficult to guarantee for wastewater containing special components (such as viscous slag and easily crystallizing salts). Furthermore, some existing heat exchangers incur significant costs for insulation. For example, some tubular heat exchangers, due to their long heat exchange tubes, have high insulation costs and poor effectiveness, affecting the economic efficiency and stability of pharmaceutical wastewater treatment. Given the urgent need in the pharmaceutical industry for efficient, energy-saving, stable, and scale-resistant wastewater treatment heat exchanger technology, a new technical solution is urgently needed to address these issues. Utility Model Content

[0005] In view of this, the present invention provides a wastewater evaporation heat exchanger structure to solve the technical problems of high energy consumption and reduced heat exchange efficiency due to impurities in the treatment of industrial electrolytic production wastewater of sodium hypochlorite and sodium chlorate in the prior art, resulting in excessively high treatment costs and insufficient stability.

[0006] This utility model embodiment provides a wastewater evaporative heat exchanger structure, including: a first heat exchange unit, including a first heat exchanger body disposed in a first cylinder, and a first water inlet, a first water outlet, a first air inlet, and a first exhaust port disposed on the first cylinder and communicating with the interior of the first cylinder; a second heat exchange unit, including a second heat exchanger body disposed in a second cylinder, and a second water inlet, a second water outlet, a second air inlet, and a second exhaust port disposed on the second cylinder and communicating with the interior of the second cylinder; a vacuum pump, including a third air inlet communicating with the first exhaust port and a third exhaust port communicating with the second air inlet; the first water outlet is connected to the second water inlet, and the second exhaust port is connected to the first air inlet.

[0007] Preferably, the first heat exchanger includes at least a first spiral tube and a second spiral tube disposed inside the first cylinder; the first spiral tube and the second spiral tube are fixed inside the first cylinder by a first set of heat exchange components; wherein, the first spiral tube is an air pipe and the second spiral tube is a water pipe.

[0008] Preferably, the first heat exchanger includes a plurality of first spiral tubes disposed inside the first cylinder and at least one second spiral tube; the first spiral tube and the second spiral tube are fixed inside the first cylinder by a first set of heat exchange components; wherein, the first spiral tube is an air pipe and the second spiral tube is a water pipe.

[0009] Preferably, the wastewater in the second spiral tube is preheated by the hot steam in the first spiral tube and the first set of heat exchangers.

[0010] Preferably, the second heat exchanger includes a plurality of heat exchange tubes disposed inside the second cylinder via a second set of heat exchange components; the second heat exchange component includes a plurality of fixed plates disposed at intervals inside the second cylinder.

[0011] Preferably, the fixing plate is circular in shape and has a notch; the notches between the two fixing plates are arranged opposite each other, and the notches form a wastewater passage inside the second cylinder so that the wastewater flows in an orderly manner inside the second cylinder.

[0012] Preferably, the vacuum pump is a vacuum compressor pump used to output high-temperature and high-pressure water vapor, which circulates between the second heat exchange unit, the first heat exchange unit, and the vacuum pump.

[0013] The wastewater evaporative heat exchanger structure provided by this utility model has the following beneficial effects:

[0014] In this invention, a closed-loop circulation system driven by a vacuum compressor pump, combined with a waste heat preheating scheme, significantly reduces the energy consumption of pharmaceutical wastewater treatment. Simultaneously, the anti-scaling properties of the spiral tube and the orderly flow channels formed by the notched fixing plate reduce the impact of impurities in the wastewater on heat exchange efficiency. This not only effectively reduces treatment costs but also ensures long-term stable heat exchange performance, thus achieving a balance between energy consumption and efficiency in pharmaceutical wastewater treatment and meeting the pharmaceutical industry's requirements for continuity, stability, and economy in wastewater treatment. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments of this utility model will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, and these are all within the protection scope of this utility model.

[0016] Figure 1 This is a structural diagram of a wastewater evaporative heat exchanger.

[0017] Figure 2 This is a schematic cross-sectional view of the first heat exchange unit;

[0018] Figure 3 This is a cross-sectional structural diagram of the second heat exchange unit;

[0019] Parts and their numbers in the diagram:

[0020] 100-First heat exchange unit, 110-First cylinder, 111-First water inlet, 112-First water outlet, 113-First air inlet, 114-First exhaust outlet, 120-First heat exchanger, 121-First spiral tube, 122-Second spiral tube, 123-First set of heat exchange components;

[0021] 200-Second heat exchange unit, 210-Second cylinder, 211-Second water inlet, 212-Second water outlet, 213-Second air inlet, 214-Second exhaust outlet, 220-Second heat exchanger, 230-Second set of heat exchange components, 231-Heat exchange tube, 232-Fixing plate;

[0022] 300 - Vacuum pump, 310 - Third air inlet, 320 - Third exhaust outlet. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, in this document, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In the description of this utility model, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Unless otherwise specified, embodiments of the present invention and the various features thereof can be combined with each other, all within the protection scope of the present invention.

[0024] Example 1

[0025] Please see Figure 1 This utility model provides a wastewater evaporative heat exchanger structure. In the industrial electrolytic production of sodium hypochlorite and sodium chlorate, wastewater treatment faces increasingly complex challenges. Sodium hypochlorite and sodium chlorate have unique compositions, often containing high concentrations of organic matter, residual slag, easily crystallizing salts, and viscous impurities, demanding extremely high stability and efficiency in the treatment process. Traditional evaporative heat exchange equipment, when treating this type of wastewater, not only suffers from excessive energy consumption due to reliance on external heat sources, increasing production costs, but is also prone to scaling and clogging of the heat exchange surface due to impurities adhering to and crystallizing in the wastewater, leading to a significant decrease in heat exchange efficiency and affecting the continuity and stability of treatment. Simultaneously, the dual requirements of environmental protection and economy in the industrial electrolytic production of sodium hypochlorite and sodium chlorate make the shortcomings of existing equipment in energy consumption control and anti-scaling capabilities increasingly prominent, becoming a key bottleneck restricting the efficient treatment of pharmaceutical wastewater. Therefore, a targeted new heat exchange structure is needed to solve these problems.

[0026] Please see Figure 1In this embodiment, a heat exchanger structure capable of heat circulation is provided. The heat exchanger structure includes a first heat exchange unit 100, a second heat exchange unit 200, and a vacuum pump 300. The first heat exchange unit 100 includes a first heat exchanger body 120 disposed within a first cylinder 110, and a first water inlet 111, a first water outlet 112, a first air inlet 113, and a first exhaust outlet 114 disposed on the first cylinder 110 and communicating with the interior of the first cylinder 110. The second heat exchange unit 200 includes a first heat exchanger body 120 disposed within a second cylinder 110. The second heat exchanger 220 is located inside the body 210, and a second water inlet 211, a second water outlet 212, a second air inlet 213, and a second exhaust outlet 214 are disposed on the second cylinder 210 and communicate with the interior of the second cylinder 210; the vacuum pump 300 includes a third air inlet 310 communicating with the first exhaust outlet 114, and a third exhaust outlet 320 communicating with the second air inlet 213; the first water outlet 112 is connected to the second water inlet 211, and the second exhaust outlet 214 is connected to the first air inlet 113.

[0027] Please see Figure 1 The heat exchanger operates on the core principle of staged wastewater treatment and closed-loop circulation of hot steam. During use:

[0028] The wastewater to be treated first enters the first heat exchange unit 100 from the first inlet 111 of the first cylinder 110. It exchanges heat with the introduced hot steam in the first heat exchanger 120 and completes the initial preheating. Then, it is transported to the second inlet 211 of the second cylinder 210 through the first outlet 112 to achieve the preheating of the wastewater. Subsequently, it enters the second heat exchange unit 200 through the first outlet 112. In the second heat exchanger 220, the wastewater fully exchanges heat with the high-temperature steam to achieve further heating (or evaporation). The treated wastewater is discharged from the second outlet 212. Meanwhile, the circulation of hot steam forms a closed loop. The third inlet 310 of the vacuum pump 300 is connected to the first exhaust port 114 of the first heat exchange unit 100, which can draw in the low-temperature steam discharged after heat exchange in the first heat exchange unit 100. After being compressed by the vacuum pump 300, the steam becomes a high-temperature and high-pressure state and is transported to the second inlet 213 of the second heat exchange unit 200 through the third exhaust port 320 to provide a heat source for the second heat exchange unit 200. After releasing heat in the second heat exchange unit 200, the steam temperature decreases and flows back into the first inlet 113 of the first heat exchange unit 100 through the second exhaust port 214 to provide residual heat for the preheating process of the first heat exchange unit 100, thus forming a circulation path of "second heat exchange unit 200 - first heat exchange unit 100 - vacuum pump 300 - second heat exchange unit 200".

[0029] This hot steam circulation operation significantly improves energy utilization. During the circulation, the steam sequentially provides a high-temperature heat source for the second heat exchange unit 200 and preheats the waste heat of the first heat exchange unit 100. This avoids the heat waste caused by the direct discharge of steam after a single use, as seen in traditional equipment, thereby reducing dependence on external energy sources and lowering operating energy consumption and costs. Simultaneously, the closed-loop circulation makes steam utilization more stable, providing a continuous and uniform heat source for the staged treatment of wastewater, ensuring the stability of heat exchange efficiency and treatment effect.

[0030] In this embodiment, a preheating cycle is used to preheat the wastewater before it enters the subsequent heat exchange stage. The preheated wastewater already has a certain temperature, reducing the temperature difference between it and the heat source (such as high-temperature steam) in the subsequent heat exchange stage. This significantly reduces the additional heat input required to achieve the same evaporation or heating target. For example, if the initial wastewater temperature is 20°C and needs to be heated to 100°C for evaporation, direct heating would require heat corresponding to an 80°C temperature difference. However, after preheating to 60°C, only a 40°C temperature difference is needed, greatly reducing the energy demand of the second heat exchange unit 200 and creating a synergistic effect with the equipment's steam cycle energy-saving design.

[0031] Furthermore, when low-temperature wastewater directly contacts a high-temperature heat exchange surface, the drastic temperature difference can easily lead to localized thermal stress concentration, and even cause "cold shock," affecting the equipment's lifespan. Simultaneously, excessive temperature differences can cause a rapid formation of a vapor film or crystallization near the heat exchange surface, hindering heat transfer. Preheating the wastewater to a temperature closer to the subsequent heat exchange temperature reduces these problems, resulting in more uniform and efficient heat transfer and ensuring the continuous and stable operation of the second heat exchange unit 200.

[0032] Further, please see Figure 2 The first heat exchanger 120 includes at least one first spiral tube 121 and one second spiral tube 122 disposed inside the first cylinder 110; the first spiral tube 121 and the second spiral tube 122 are fixed inside the first cylinder 110 by a first set of heat exchange components 123; wherein, the first spiral tube 121 is an air pipe and the second spiral tube 122 is a water pipe.

[0033] Furthermore, the first heat exchanger 120 includes a plurality of first spiral tubes 121 disposed inside the first cylinder 110 and at least one second spiral tube 122; the first spiral tubes 121 and the second spiral tubes 122 are fixed inside the first cylinder 110 by a first set of heat exchange components 123; wherein, the first spiral tube 121 is an air pipe and the second spiral tube 122 is a water pipe.

[0034] Furthermore, the wastewater in the second spiral tube 122 is preheated by the hot steam in the first spiral tube 121 and the first set of heat exchange elements 123.

[0035] In this heat exchanger structure, the preheating process is mainly achieved through the spiral tube structure of the first heat exchanger 120 and the transfer of heat to the gas, as follows:

[0036] Please see Figure 2 The wastewater to be preheated enters the first cylinder 110 through the first inlet 111 and flows into the second spiral tube 122, which serves as a water pipe. The hot air used for preheating enters the first spiral tube 121, which serves as an air pipe, through the first air inlet 113. Since both the first spiral tube 121 and the second spiral tube 122 are located inside the first cylinder 110 and are fixed by the first set of heat exchange elements 123, the two spiral tubes are arranged closely in space, forming a highly efficient heat exchange environment. The hot air in the first spiral tube 121 directly transfers heat to the wastewater in the second spiral tube 122 through the tube wall. At the same time, the first set of heat exchange elements 123, as a connecting and fixing structure, can also assist in heat conduction, further improving the heat exchange efficiency.

[0037] As the wastewater continues to flow within the second spiral tube 122, it comes into full contact with the hot steam in the first spiral tube 121 along the spiral path, gradually absorbing heat to complete preheating. The preheated wastewater is discharged from the first heat exchange unit 100 through the first outlet 112 and enters the second inlet 211 of the second heat exchange unit 200, laying the foundation for subsequent heat exchange (such as evaporation) in the second heat exchanger 220. This design, which utilizes the long-path contact of the spiral tube and the auxiliary heat transfer of the heat exchange components, allows the wastewater to heat up uniformly during flow, ensuring the stability and sufficiency of the preheating effect.

[0038] Further, please see Figure 3 The second heat exchanger 220 includes a plurality of heat exchange tubes 231 disposed inside the second cylinder 210 via a second set of heat exchange components 230; the second set of heat exchange components 230 includes a plurality of fixed plates 232 disposed at intervals inside the second cylinder 210.

[0039] Furthermore, the fixing plate 232 is generally circular and has a notch. The notches between the two fixing plates 232 are arranged opposite each other, and the notches form a wastewater passage inside the second cylinder 210 so that the wastewater flows in an orderly manner inside the second cylinder 210.

[0040] Furthermore, the vacuum pump 300 is a vacuum compression pump used to output high-temperature and high-pressure water vapor, which circulates between the second heat exchange unit 200, the first heat exchange unit 100 and the vacuum pump 300.

[0041] When the second heat exchange unit 200 is in operation, the wastewater preheated by the first heat exchange unit 100 enters the second cylinder 210 through the second inlet 211 and flows into several heat exchange tubes 231 fixed by the second set of heat exchange components 230. At this time, high-temperature and high-pressure steam is generated by the vacuum pump 300 and enters the interior of the second cylinder 210 through the second air inlet 213, forming a heat exchange with the wastewater in the heat exchange tubes 231. The heat of the steam is transferred to the wastewater through the wall of the heat exchange tubes 231, causing the wastewater temperature to rise continuously.

[0042] Meanwhile, the fixing plates 232 in the second set of heat exchange components 230 are arranged at intervals by several circular fixing plates 232 with notches, and the notches of adjacent fixing plates 232 are arranged opposite each other, forming a meandering wastewater flow channel inside the second cylinder 210. When the wastewater flows in the heat exchange tube 231, it can only pass through the notches in an orderly manner due to the guiding effect of the channel, which prolongs the residence time in the second cylinder 210, and it is not easy to form dead corners during the flow process, ensuring that the wastewater in each section of the heat exchange tube 231 can fully contact the external steam, so as to achieve uniform and efficient secondary heating.

[0043] After preheating and the second heat exchange, the wastewater is usually in a high-temperature evaporation state. The preheating stage raises the temperature of the wastewater to near the evaporation threshold, while the second heat exchange provides enough heat for the wastewater to reach its boiling point. Volatile components (such as water and low-boiling-point organic solvents) evaporate into steam in large quantities, while high-concentration solutes (such as drug residues, salts, and organic pollutants) remain in the remaining waste liquid, forming a concentrated liquid.

[0044] This staged treatment method yields significant results: firstly, the seamless integration of preheating and secondary heat exchange greatly reduces energy waste, as the heat from the steam is utilized in a tiered manner, meeting energy-saving requirements; secondly, after evaporation and separation, the volume of wastewater is significantly reduced, necessitating further deep treatment of the concentrate (such as crystallization recovery and harmless disposal), thus lowering overall treatment costs. Simultaneously, the orderly flow channels formed by the fixed plate 232 prevent localized overheating or impurity deposition caused by wastewater stagnation, ensuring the stability of heat exchange efficiency and making wastewater treatment more controllable. This is particularly suitable for scenarios in industries such as pharmaceuticals and chemicals where high precision in wastewater treatment is required.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A wastewater evaporative heat exchanger structure, characterized in that, include: The first heat exchange unit (100) includes a first heat exchanger (120) disposed in the first cylinder (110), and a first water inlet (111), a first water outlet (112), a first air inlet (113) and a first exhaust outlet (114) disposed on the first cylinder (110) and communicating with the interior of the first cylinder (110). The second heat exchange unit (200) includes a second heat exchanger (220) disposed in the second cylinder (210), and a second water inlet (211), a second water outlet (212), a second air inlet (213) and a second exhaust outlet (214) disposed on the second cylinder (210) and communicating with the interior of the second cylinder (210); The vacuum pump (300) includes a third air inlet (310) communicating with the first exhaust port (114) and a third exhaust port (320) communicating with the second air inlet (213); The first water outlet (112) is connected to the second water inlet (211), and the second exhaust outlet (214) is connected to the first air inlet (113).

2. The wastewater evaporative heat exchanger structure according to claim 1, characterized in that, The first heat exchanger (120) includes at least one first spiral tube (121) and one second spiral tube (122) disposed inside the first cylinder (110); The first spiral tube (121) and the second spiral tube (122) are fixed inside the first cylinder (110) by the first set of heat exchange components (123); The first spiral tube (121) is an air tube, and the second spiral tube (122) is a water tube.

3. The wastewater evaporative heat exchanger structure according to claim 1, characterized in that, The first heat exchanger (120) includes a plurality of first spiral tubes (121) disposed inside the first cylinder (110) and at least one second spiral tube (122); The first spiral tube (121) and the second spiral tube (122) are fixed inside the first cylinder (110) by the first set of heat exchange components (123); The first spiral tube (121) is an air tube, and the second spiral tube (122) is a water tube.

4. A wastewater evaporative heat exchanger structure according to any one of claims 2 and 3, characterized in that, Wastewater in the second spiral tube (122) is preheated by hot steam in the first spiral tube (121) and the first set of heat exchangers (123).

5. The wastewater evaporative heat exchanger structure according to claim 1, characterized in that, The second heat exchanger (220) includes a plurality of heat exchange tubes (231) disposed inside the second cylinder (210) via a second set of heat exchange elements (230); The second heat exchanger (230) includes a plurality of fixed plates (232) spaced apart inside the second cylinder (210).

6. The wastewater evaporative heat exchanger structure according to claim 5, characterized in that, The fixing plate (232) is generally circular, and a notch is provided on the fixing plate (232); The gaps between the two fixed plates (232) are arranged opposite to each other, and the gaps form a wastewater passage inside the second cylinder (210) so that the wastewater flows in an orderly manner inside the second cylinder (210).

7. The wastewater evaporative heat exchanger structure according to claim 1, characterized in that, The vacuum pump (300) is a vacuum compression pump used to output high-temperature and high-pressure water vapor, which circulates between the second heat exchange unit (200), the first heat exchange unit (100) and the vacuum pump (300).

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