Black water heat exchanger

Abstract

The invention discloses a black water heat exchanger, which relates to the technical field of black water treatment and comprises a shell, an upper tube plate, an upper tube box, a heat exchange tube and a lower tube box, the shell is of a vertically-placed vertical structure, an upper tube plate is arranged at the top of the shell, an upper tube box is arranged at the top of the upper tube plate, a black water inlet and a black water outlet are formed in the upper tube box, the heat exchanger comprises two shell passes and two tube passes, the top of the first tube pass is connected with the upper tube plate and communicated with the black water inlet, and the bottom of the first tube pass is connected with the bottom of the second tube pass through a lower tube box. The top of the tube pass II is connected with the upper tube plate and communicated with the black water outlet; a partition plate for dividing the inner cavity into a left part and a right part is arranged in the shell, and the bottoms of the two cavities are communicated; a plurality of black water inlets are formed in the upper pipe box and are oppositely arranged in pairs; the heat exchange pipe is a corrugated pipe; the efficiency of the black water heat exchange process is improved, the blocking phenomenon is not prone to occurring, and the service life is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of black water treatment, in particular to a black water heat exchanger. Background Art

[0002] (1) Industry status and blackwater generation

[0003] Modern industrial production processes, such as coal chemical processing and coal gasification, are complex and diverse. The conversion of coal into various chemical products or gases inevitably generates large amounts of high-temperature blackwater. For example, during coal gasification, coal reacts with a gasifying agent under high temperature and pressure, producing not only the target gas product but also blackwater containing numerous impurities. This blackwater, with its high temperature and complex composition, becomes a critical component of the industrial production process requiring proper handling.

[0004] (2) Disadvantages of direct emissions

[0005] 1. Energy Waste

[0006] Directly discharging high-temperature black water means that a significant amount of the heat energy contained within is lost to the environment without recovery. Against the backdrop of increasingly severe global energy tensions, companies must strive for efficient energy utilization in every production activity. This energy waste directly increases a company's energy procurement costs, as it requires additional energy consumption to meet the needs of other production processes. Furthermore, in the long term, this weakens a company's market competitiveness and runs counter to the principle of sustainable industrial development.

[0007] 2. Environmental protection issues

[0008] The impact of thermal pollution caused by the discharge of high-temperature blackwater on the ecological environment cannot be underestimated. When high-temperature blackwater is discharged into a body of water, it causes a localized increase in water temperature. This represents a drastic change in the living environment for aquatic organisms. Many aquatic organisms are extremely sensitive to changes in water temperature; maintaining an optimal water temperature range is crucial for their survival and reproduction. Increased water temperature can reduce dissolved oxygen levels, affecting the respiration of aquatic organisms. It can also alter the chemical balance of the water, accelerating certain chemical reactions and releasing harmful substances. This can alter the local ecological balance and threaten the stability of the entire ecosystem.

[0009] 3. Impact on subsequent processes

[0010] (1) The temperature does not meet the requirements

[0011] Subsequent processes often have strict water temperature requirements. For example, the synthesis of certain chemical products requires raw water within a specific temperature range. Excessively high water temperatures can cause runaway reaction rates, resulting in the formation of byproducts and impacting product quality and yield. Directly introducing high-temperature black water into subsequent processes will inevitably disrupt the temperature control system of the entire production process, severely interfering with the normal flow of production.

[0012] (2) Equipment damage risk

[0013] The characteristics of high-temperature black water make it potentially damaging to related equipment. Prolonged exposure to high temperatures can alter the physical properties of equipment, such as reduced strength and expansion and deformation of metal materials. This can not only shorten the lifespan of equipment and increase the frequency and cost of repairs, but can also lead to sudden equipment failure, causing production accidents, resulting in greater economic losses and safety hazards.

[0014] (3) Advantages of black water heat exchanger

[0015] 1. Ensure the stability of subsequent processes

[0016] By cooling the black water through a black water heat exchanger, the temperature of the black water can be precisely adjusted to the required range for subsequent processes. This provides stable raw water conditions for subsequent processes, ensuring that the production process can proceed in an orderly manner according to the predetermined process parameters, and avoiding problems such as process fluctuations and unstable product quality caused by water temperature issues.

[0017] 2. Energy recovery and optimal utilization

[0018] During the cooling process, the blackwater heat exchanger effectively recovers heat from the blackwater. This recovered heat can be cleverly applied to other process steps, such as heating other materials that require heating or replenishing energy during the evaporation process. This cascaded heat utilization significantly improves the energy efficiency of the entire production system, reducing the company's reliance on external energy sources, thereby reducing energy consumption and production costs, achieving a win-win situation of energy conservation, emission reduction, and improved economic benefits.

[0019] (4) Challenges faced by conventional heat exchangers

[0020] Gasification black water contains large amounts of suspended matter, such as fine ash and slag, and its high hardness, alkalinity, and chloride ion content make it difficult for conventional heat exchangers to process this water. During the initial operation, large amounts of slag and fine ash quickly accumulate at the heat exchanger inlet, forming a barrier that hinders the smooth flow of black water. Over time, this blockage worsens, causing the flow rate of black water within the heat exchanger to steadily slow. With this reduced flow rate, the fine ash and slag lose the effective flushing force of the water flow, accelerating their deposition within the heat exchanger's flow channels. These deposits gradually accumulate, narrowing the flow channels and ultimately significantly reducing the flow rate of black water, severely disrupting the entire production process. Under these conditions, the heat exchanger is unable to effectively extract and utilize the waste heat from the black water. Furthermore, the slag in the black water, carried by the water flow, causes continuous wear on heat transfer components, further reducing the performance and service life of the heat exchanger.

[0021] In summary, existing black water heat exchangers have problems such as easy blockage of inlets and flow channels, low heat exchange efficiency, and short service life. Summary of the Invention

[0022] The purpose of the present invention is to provide a black water heat exchanger to solve the problems existing in the above-mentioned prior art, thereby improving the efficiency of the black water heat exchange process, making it less prone to clogging and increasing its service life.

[0023] To achieve the above object, the present invention provides the following solutions:

[0024] The present invention provides a black water heat exchanger, comprising a shell, an upper tube sheet, an upper tube box, heat exchange tubes and a lower tube box; wherein the shell is a vertical structure placed vertically, an upper tube sheet is arranged on the top of the shell, the top of the upper tube sheet is an upper tube box, a black water inlet and a black water outlet are arranged on the upper tube box, the heat exchange tube comprises a tube pass 1 and a tube pass 2, the top of the tube pass 1 is connected to the upper tube sheet and communicated with the black water inlet, the bottom of the tube pass 1 is connected to the bottom of the tube pass 2 through the lower tube box, the tube pass 2 The top is connected to the upper tube plate and connected to the black water outlet; a partition is provided in the shell to divide the inner cavity into left and right parts, the tube side one and the tube side two are respectively located in the two cavities, and the bottoms of the two cavities are connected, and a coolant inlet connected to the left inner cavity is provided on the shell at the bottom of the black water outlet, and a coolant outlet connected to the right inner cavity is provided on the shell at the bottom of the black water inlet; multiple black water inlets are provided on the upper tube box, and are arranged opposite to each other in pairs; the heat exchange tube is a corrugated tube.

[0025] Preferably, a partition plate is provided inside the upper tube box to divide the inner cavity, the inner cavity on one side of the partition plate is connected to the black water inlet, and the inner cavity on the other side of the partition plate is connected to the black water outlet.

[0026] Preferably, a baffle is provided in the inner cavity of the upper tube box on the black water outlet side. The baffle is provided above the black water outlet and the angle between the baffle and the inner wall of the upper tube box is 30° to 60°.

[0027] Preferably, the lower pipe box includes a joint 1, an elbow and a joint 2. The joint 1 and the joint 2 have the same structure and are respectively connected to the bottom of the pipe pass 1 and the pipe pass 2. The joint 1 and the joint 2 include a semicircular short section at the top and an inclined cone at the bottom. The top of the inclined cone is circular, the inner cavity diameter of the inclined cone gradually becomes smaller and the bottom is semicircular, and the bottom of the inclined cones of the joint 1 and the joint 2 are connected through the elbow.

[0028] Preferably, a spoiler device is provided in the elbow, and the spoiler device includes a curved spoiler tube and a spoiler plate provided outside the spoiler tube, and the spoiler plate is a spiral plate spirally arranged on the spoiler tube, and a flow equalizer is provided on the spoiler tube near the second joint.

[0029] Compared with the prior art, the present invention has achieved the following technical effects:

[0030] 1. Adopt vertical BFM structure

[0031] The blackwater heat exchanger adopts a vertical design, a structural form that offers unique advantages in space utilization and fluid mechanics. The double-shell-side, double-tube-side structural layout provides ample heat exchange area and complex flow paths between the blackwater and the shell-side fluid, facilitating sufficient heat exchange. The pure countercurrent heat exchange method further improves heat exchange efficiency. During countercurrent heat exchange, the blackwater and shell-side fluid flow in opposite directions within the heat exchanger, ensuring that the temperature difference between the two remains at a high value throughout the heat exchange process. According to the principles of heat transfer, a larger temperature difference can drive more heat from the high-temperature blackwater to the low-temperature shell-side fluid, thereby achieving efficient heat recovery.

[0032] 2. Use corrugated heat exchange tubes

[0033] The heat exchange tubes utilize an advanced bellows design, featuring continuous internal and external corrugations that exhibit unique fluid dynamics. When the liquid flows through the tubes, this corrugated structure cleverly induces a fully turbulent flow, effectively breaking the limitations of traditional laminar boundary layers and significantly improving the heat transfer coefficient within the tubes. Furthermore, the unique corrugated shape of the bellows promotes sufficient turbulence within and between the media, continuously scouring the tube walls. Furthermore, the specially treated tube surface provides exceptional smoothness, making it highly resistant to scaling. Even if scaling does occur during long-term operation, the inherent flexibility of the bellows allows for a certain degree of axial expansion and contraction under the influence of thermal stress. Furthermore, the significant difference in linear expansion coefficients between the scale and the metal bellows creates a significant pull-off force between the scale and the tube wall. This pull-off force is sufficient to dislodge the scale, enabling automatic scale removal, which is particularly effective for removing hard and brittle scale. This automatic descaling feature not only ensures the long-term efficient heat exchange performance of the heat exchange tubes, reduces the cost and workload of manual cleaning and maintenance, but also effectively extends the service life of the heat exchange tubes and improves the reliability and stability of the entire heat exchanger.

[0034] 3. Special layout and baffle design of tube inlet

[0035] The tube-side inlet (black water inlet) can have two to six inlets arranged in opposing directions on either side of the upper tube box. This unique arrangement creates an "accelerator channel" for the inflow of black water. When black water flows into the tube-side from two opposing directions simultaneously, a strong counteraction effect is created, effectively accelerating the inlet flow rate. The turbulent water flow creates a strong turbulence, making it difficult for suspended matter in the black water to settle on the tube sheet. A baffle is installed directly above the black water outlet, forming an angle of 30 to 60 degrees with the cylinder. By comprehensively considering key parameters such as the number and diameter of the heat exchange tubes and the equipment diameter, the baffle position is calculated to appropriately reduce the flow space at the tube box outlet. As the black water flows out of the tube-side and into the upper tube box, the flow space does not suddenly increase, allowing the black water flow rate to remain relatively stable, avoiding the problem of suspended matter settling caused by a sudden drop in flow rate.

[0036] 4. Tube box structure and spoiler rod design

[0037] Each pipe passage has a pipe box, which is composed of a semicircular short section and an oblique cone with a semicircular bottom and a circular top. The two pipe boxes are connected by a 180° elbow. This structure is not only conducive to the smooth transition of black water in the pipe box and the change of flow direction, but also has a turbulent device inside the elbow (such as Figure 3(As shown), this flow-disrupting device can increase the flow rate and turbulence. It ensures that dust does not settle and can be carried into the second pipe by the fluid. The flow-disrupting device consists of two parts: a spoiler and a spoiler tube. Relevant calculations ensure that the flow rate of the fluid in the flow-disrupting device is 2 to 3 m / s, and two more flow-distributing plates are set at the outlet of the flow-disrupting device. The purpose is to make the material more evenly distributed at the outlet and the flow rate more uniform. The addition of the flow-disrupting device is like setting up a series of "barriers" in the fluid, which further enhances the disturbance effect of the fluid. When black water passes through the elbow, the flow-disrupting device can break the steady state of the water flow, making it difficult for suspended matter to settle at the elbow, thereby ensuring the smooth flow of the fluid in the pipe box and preventing the problem of poor flow in the entire pipe due to blockage at the elbow. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 Schematic diagram of the structure of the black water heat exchanger in the present invention;

[0040] Figure 2 Schematic diagram of the internal structure of the shell in the present invention;

[0041] Figure 3 Schematic diagram of the structure of the lower pipe box in the present invention;

[0042] Figure 4 Schematic diagram of the structure of the spoiler tube in the present invention;

[0043] In the figure: 1. Shell; 2. Upper tube sheet; 3. Upper tube box; 4. Heat exchange tube; 5. Lower tube box; 6. Black water inlet; 7. Black water outlet; 8. Coolant inlet; 9. Coolant outlet; 10. Baffle; 11. Semicircular short section; 12. Oblique cone; 13. Elbow; 14. Spoiler; 15. Spoiler; 16. Flow equalizer; 17. Lower tube sheet; 18. Partition plate. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 efforts are within the scope of protection of the present invention.

[0045] The purpose of the present invention is to provide a black water heat exchanger to solve the problems existing in the prior art.

[0046] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] The black water heat exchanger in this embodiment, such as Figure 1-Figure 4 As shown, it includes a shell 1, an upper tube sheet 2, an upper tube box 3, a heat exchange tube 4 and a lower tube box 5; wherein the shell 1 is a vertical structure placed vertically, the upper tube sheet 2 is arranged on the top of the shell 1, the upper tube box 3 is on the top of the upper tube sheet 2, a black water inlet 6 and a black water outlet 7 are arranged on the upper tube box 3, the heat exchange tube 4 includes a tube pass 1 and a tube pass 2, the top of the tube pass 1 is connected to the upper tube sheet 2 and is connected to the black water inlet 6, the bottom of the tube pass 1 is connected to the bottom of the tube pass 2 through the lower tube box 5, and the tube pass 2 is connected to the bottom of the tube pass 2. The top is connected to the upper tube sheet 2 and connected to the black water outlet 7; a partition is provided in the shell 1 to divide the inner cavity into two parts, left and right, and the tube side 1 and the tube side 2 are respectively located in the two cavities, and the bottoms of the two cavities are connected. A coolant inlet 8 connected to the left inner cavity is provided on the shell 1 at the bottom of the black water outlet 7, and a coolant outlet 9 connected to the right inner cavity is provided on the shell 1 at the bottom of the black water inlet 6; multiple black water inlets 6 are provided on the upper tube box 3, and are arranged opposite to each other in pairs; the heat exchange tube 4 is a corrugated tube.

[0048] In this specific embodiment, a partition plate 18 is provided inside the upper tube box 3 to divide the inner cavity. The inner cavity on one side of the partition plate 18 is connected to the black water inlet 6, and the inner cavity on the other side of the partition plate 18 is connected to the black water outlet 7.

[0049] In this specific embodiment, a baffle 10 is provided in the inner cavity of the upper tube box 3 on the side of the black water outlet 7. The baffle 10 is provided above the black water outlet 7 and the angle between the baffle 10 and the inner wall of the upper tube box 3 is 30° to 60°.

[0050] In this specific embodiment, the lower pipe box 5 includes a joint 1, an elbow 13 and a joint 2. The joint 1 and the joint 2 have the same structure and are respectively connected to the bottom of the pipe pass 1 and the pipe pass 2. The joint 1 and the joint 2 include a semicircular short section 11 at the top and an inclined cone 12 at the bottom. The top of the semicircular short section 11 is connected to the lower tube plate 17. The top of the inclined cone 12 is circular, the inner cavity diameter of the inclined cone 12 gradually decreases and the bottom is semicircular. The bottom of the inclined cone 12 of the joint 1 and the joint 2 is connected by an elbow 13.

[0051] In this specific embodiment, a flow-disturbing device is provided in the elbow 13, and the flow-disturbing device includes a curved flow-disturbing tube 14 and a flow-disturbing plate 15 provided outside the flow-disturbing tube 14. The flow-disturbing plate 15 is a spiral plate spirally coiled on the flow-disturbing tube 14, and a flow-disturbing plate 16 is provided on the flow-disturbing tube 14 near the second joint.

[0052] The working principle of the black water heat exchanger in the present invention is as follows:

[0053] 1. Adopt vertical BFM structure

[0054] The black water heat exchanger adopts a vertical design (such as Figure 1 This structural form offers unique advantages in terms of space utilization and fluid dynamics. The double-shell-side, double-tube-side layout provides ample heat exchange area and complex flow paths between the blackwater and the shell-side fluid, facilitating efficient heat exchange. Pure countercurrent heat exchange further enhances heat exchange efficiency. During countercurrent heat exchange, the blackwater and shell-side fluid flow in opposite directions within the heat exchanger, maintaining a high temperature differential between them throughout the entire process. According to heat transfer principles, a larger temperature differential drives more heat transfer from the high-temperature blackwater to the low-temperature shell-side fluid, thereby achieving efficient heat recovery.

[0055] 2. Use corrugated heat exchange tubes

[0056] The heat exchange tubes utilize an advanced bellows design, featuring continuous internal and external corrugations that exhibit unique fluid dynamics. When the liquid flows through the tubes, this corrugated structure cleverly induces a fully turbulent flow, effectively breaking the limitations of traditional laminar boundary layers and significantly improving the heat transfer coefficient within the tubes. Furthermore, the unique corrugated shape of the bellows promotes sufficient turbulence within and between the media, continuously scouring the tube walls. Furthermore, the specially treated tube surface provides exceptional smoothness, making it highly resistant to scaling. Even if scaling does occur during long-term operation, the inherent flexibility of the bellows allows for a certain degree of axial expansion and contraction under the influence of thermal stress. Furthermore, the significant difference in linear expansion coefficients between the scale and the metal bellows creates a significant pull-off force between the scale and the tube wall. This pull-off force is sufficient to dislodge the scale, enabling automatic scale removal, which is particularly effective for removing hard and brittle scale. This automatic descaling feature not only ensures the long-term efficient heat exchange performance of the heat exchange tube 4, reduces the cost and workload of manual cleaning and maintenance, but also effectively extends the service life of the heat exchange tube 4 and improves the reliability and stability of the entire heat exchanger.

[0057] 3. Special layout of tube inlet and baffle 10 design

[0058] The inlet of the tube pass (black water inlet) can be set up with 2 to 6 inlets arranged opposite to each other on both sides of the upper tube box. This unique arrangement is like creating an "acceleration channel" for the inflow of black water. When black water flows into the tube pass from two opposite directions at the same time, a strong impact effect will be formed, effectively accelerating the inlet flow rate. The turbulent water flow can produce a strong turbulent effect, making it difficult for suspended matter in the black water to settle on the tube sheet. A baffle 10 (such as Figure 1 (as shown), baffle 10 forms an angle of 30-60° with the cylinder. Taking into account key parameters such as the number and diameter of the heat exchange tubes 4 and the equipment diameter, the calculated position of baffle 10 precisely reduces the flow space at the tube box outlet. When black water flows from the tube side into the upper tube box, the flow space does not suddenly increase, allowing the black water flow rate to remain relatively stable, thus avoiding the problem of suspended solids settling caused by a sudden drop in flow rate.

[0059] 4. Tube box structure and spoiler rod design

[0060] The structural design of the lower tube box 5 is unique (such as Figure 2 As shown in the figure, each pipe passage is provided with a pipe box, which is composed of a semicircular short section 11 and an oblique cone 12 with a semicircular bottom and a circular top. The two pipe boxes are connected by a 180° elbow 13. This structure is not only conducive to the smooth transition of black water in the pipe box and the change of flow direction, but also has a turbulent device inside the elbow 13 (such as Figure 3 As shown), this flow-disrupting device can increase the flow velocity and turbulence. It ensures that dust does not settle and can be brought into the second pipe pass by the fluid. The flow-disrupting device consists of two parts: a spoiler 15 and a spoiler tube 14. Through relevant calculations, the flow velocity of the fluid in the flow-disrupting device is guaranteed to be 2 to 3 m / s, and two more flow-uniform plates 16 are set at the outlet of the flow-disrupting device. The purpose is to make the material more evenly distributed at the outlet and the flow velocity more uniform. The addition of the flow-disrupting device is like setting up a series of "barriers" in the fluid, which further enhances the disturbance effect of the fluid. When the black water passes through the elbow 13, the flow-disrupting device can break the steady state of the water flow, making it difficult for suspended matter to settle at the elbow 13, thereby ensuring the smooth flow of the fluid in the pipe box and preventing the problem of poor flow in the entire pipe pass due to blockage at the elbow 13.

[0061] The working process of the black water heat exchanger in the present invention is as follows:

[0062] Black water first enters the heat exchanger through the black water inlet 6. Due to the uniquely oriented inlet arrangement and the internal structural design of the tube side, the black water experiences a high velocity and intense turbulence upon entering the tube side. This velocity and turbulence are maintained throughout the tube side, keeping suspended matter in the black water in suspension and preventing it from depositing on the tube sheets and the inner walls of the heat exchange tubes 4. Simultaneously, in the shell side, the corresponding fluid begins to flow, driven by the pump. Through the double-shell-side and double-tube-side structure and pure countercurrent heat exchange, the black water exchanges heat with the fluid in the shell side. During this process, the black water continuously transfers heat to the shell side fluid, gradually cooling its own temperature. After absorbing the heat, the shell side fluid increases in temperature, achieving heat recovery and utilization. Finally, the cooled black water exits the heat exchanger through the black water outlet 7, completing the heat exchange process. Throughout the entire process, the coordinated operation of various components ensures the efficient and stable operation of the black water heat exchanger, effectively solving the challenge of black water waste heat recovery and treatment.

[0063] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A black water heat exchanger, characterized in that: The heat exchanger comprises a shell, an upper tube sheet, an upper tube box, heat exchange tubes and a lower tube box; wherein, the shell is a vertical structure placed vertically, an upper tube sheet is arranged on the top of the shell, the top of the upper tube sheet is an upper tube box, a black water inlet and a black water outlet are arranged on the upper tube box, and the heat exchanger has two shell passes and two tube passes, the top of the tube pass one is connected to the upper tube sheet and communicated with the black water inlet, the bottom of the tube pass one is connected to the bottom of the tube pass two through the lower tube box, the top of the tube pass two is connected to the upper tube sheet and communicated with the black water outlet; a partition is arranged in the shell to divide the inner cavity into left and right parts, the tube pass one and the tube pass two are respectively located in the two cavities, the bottoms of the two cavities are connected, a coolant inlet communicating with the left inner cavity is arranged on the shell at the bottom of the black water outlet, and a coolant outlet communicating with the right inner cavity is arranged on the shell at the bottom of the black water inlet; a plurality of black water inlets are arranged on the upper tube box, and are arranged opposite to each other in pairs; the heat exchange tubes are corrugated tubes.

2. The black water heat exchanger according to claim 1, characterized in that: A partition plate is provided inside the upper tube box to divide the inner cavity. The inner cavity on one side of the partition plate is connected to the black water inlet, and the inner cavity on the other side of the partition plate is connected to the black water outlet.

3. The black water heat exchanger according to claim 2, characterized in that: A baffle is provided in the inner cavity of the upper tube box on the black water outlet side. The baffle is provided above the black water outlet and the angle between the baffle and the inner wall of the upper tube box is 30° to 60°.

4. The black water heat exchanger according to claim 1, characterized in that: The lower pipe box includes a joint 1, an elbow and a joint 2. The joint 1 and the joint 2 have the same structure and are respectively connected to the bottom of the pipe pass 1 and the pipe pass 2. The joint 1 and the joint 2 include a semicircular short section at the top and an inclined cone at the bottom. The top of the inclined cone is circular, the inner cavity diameter of the inclined cone gradually decreases and the bottom is semicircular, and the bottom of the inclined cone of the joint 1 and the joint 2 is connected through the elbow.

5. The black water heat exchanger according to claim 4, characterized in that: A flow-disturbing device is provided in the elbow, and the flow-disturbing device includes a curved flow-disturbing tube and a flow-disturbing plate provided outside the flow-disturbing tube. The flow-disturbing plate is a spiral plate spirally disposed on the flow-disturbing tube, and a flow-uniforming plate is provided on the flow-disturbing tube near the second joint.

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