Low-temperature economizer heat exchange unit and heat exchange core assembly

Abstract

The utility model discloses a low-temperature economizer heat exchange unit and a heat exchange core assembly, the low-temperature economizer heat exchange unit comprises a plurality of heat exchange tubes arranged side by side, the heat exchange tubes are vertically arranged, the top of each heat exchange tube is connected with a first distribution tube, and an exhaust valve is arranged on each first distribution tube; the bottom of each heat exchange tube is connected with a second distribution tube, and a drain valve is arranged on each second distribution tube; a heat exchange medium inlet and a heat exchange medium outlet are formed in the distribution pipe, and a refrigerant medium channel is formed by an inner cavity of the first distribution pipe, an inner cavity of the second distribution pipe and an inner cavity of the heat exchange pipe; the heat exchange core assembly is formed by connecting a plurality of low-temperature economizer heat exchange units in series. The heat exchanger can effectively prevent dust from being accumulated on the pipe wall, facilitates liquid discharge and air exhaust, and is good in heat exchange effect.

Description

Technical Field

[0001] The utility model relates to a economizer, in particular to a low-temperature economizer heat exchange unit and a heat exchange core assembly. Background Art

[0002] In a coal-fired boiler system, it is usually necessary to install an economizer (a device / equipment for recovering the waste heat of the exhausted flue gas) in the boiler flue to improve the heat conversion efficiency.

[0003] The existing literature CN218269024U discloses an anti-blocking economizer, the pipes of which are continuously arranged in a U shape. Since the cooling water will vaporize due to the high-temperature flue gas in the pipes, this leads to air plugs in the pipes. According to the existing U-shaped pipe manufacturing specifications, it is not possible to open holes at the arc ends of the U-shaped pipes, which makes it inconvenient to discharge the water vapor in the pipes, resulting in overheating and water hammer phenomena in local areas and affecting the flue gas heat exchange effect.

[0004] On the other hand, traditional economizers are usually arranged horizontally. When flue gas passes outside the pipes, ash is likely to accumulate on the pipe walls (including the ash formed by the adhesion of molten ammonium bisulfate and fly ash on the pipe walls), thereby affecting the heat exchange effect. The solution to this is usually to configure soot blowers. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a low-temperature economizer heat exchange unit and a heat exchange core assembly, which can solve the problems of drainage and exhaust in the heat exchange pipes, and solve the problems of ash accumulation and ammonium bisulfate deposition in the heat exchange pipes.

[0006] The utility model provides the following technical solutions.

[0007] A low-temperature economizer heat exchange unit is arranged in a horizontal flue and includes a plurality of heat exchange pipes arranged side by side. The heat exchange pipes are arranged vertically. The top of each heat exchange pipe is connected to a first distribution pipe, and an exhaust valve is arranged on the first distribution pipe; the bottom of each heat exchange pipe is connected to a second distribution pipe, and a drain valve is arranged on the second distribution pipe; heat exchange medium inlets and outlets are arranged on the distribution pipes, and a refrigerant medium channel is jointly formed by the inner cavities of the first distribution pipe, the second distribution pipe, and the heat exchange pipes.

[0008] Further, the first distribution pipe and the second distribution pipe are arranged horizontally.

[0009] Further, the center of the first distribution pipe and the center of the second distribution pipe are not in the same vertical plane.

[0010] Further, the distribution pipes and the heat exchange pipes are connected through elbow sections. The elbow sections are made of elbows or are bent from the upper sections of the heat exchange pipes to realize the diagonal arrangement of the end sections of the heat exchange pipes.

[0011] Further, two symmetrically arranged second distribution pipes are adopted, and two groups of symmetrically arranged heat exchange pipes are used. The center of symmetry is the center line of the first distribution pipe in the vertical direction. The heat exchange medium inlet is arranged on one of the second distribution pipes, and the heat exchange medium outlet is arranged on the other second distribution pipe. The first distribution pipe serves as a heat exchange medium transfer chamber; the included angle between two elbow sections connected to the same distribution pipe is 20 to 90°.

[0012] A heat exchange core assembly of the low-temperature economizer heat exchange unit as described above, in which a plurality of the low-temperature economizer heat exchange units are connected in series, and the refrigerant medium channels of all the low-temperature economizer heat exchange units are communicated.

[0013] Further, the lower ends of the heat exchange pipes of adjacent low-temperature economizer heat exchange units share the same second distribution pipe, and such a structure is more compact.

[0014] Further, the outside of the pipes of the low-temperature economizer heat exchange unit serves as a flue gas channel; a baffle door is arranged in the flue gas channel and on the flue gas inlet side, and the baffle door is used to open or close the flue gas channel.

[0015] Further, a high-temperature medium pipe (the temperature of the high-temperature medium is not lower than 500 °C) is arranged between adjacent low-temperature economizer heat exchange units, and the high-temperature medium pipe is externally connected to a high-temperature medium supply system to enable the introduction of high-temperature medium into the flue gas channel. With such a solution, when the flue gas channel is closed and high-temperature medium is introduced, it is convenient to rapidly heat up the pipe wall of the heat exchange pipe, and it is possible to effectively remove ammonium bisulfate on the pipe wall.

[0016] Further, multiple groups of heat exchange core assemblies are arranged side by side, and each group of heat exchange core assemblies is equipped with the baffle door and the high-temperature medium pipe.

[0017] Advantages of the present invention: The present invention can not only effectively alleviate the fouling of the low-temperature economizer heat exchange core, but also does not require the arrangement of soot blowers, and is also convenient for timely exhausting the gas and water in the heat exchange pipes; during use, the gas in the heat exchange pipes is discharged through the exhaust valve, and the accumulated water in the heat exchange pipes is discharged through the drain valve to play a role in draining water and exhausting gas, improving the durability and safety of the heat exchange pipes; a plurality of exhaust valves and drain valves are provided, which can uniformly and fully discharge the water and gas in multiple parts of the heat exchange pipes, avoiding overheating and water hammer phenomena in local areas, and improving the heat exchange effect of the flue gas. In addition, a plurality of distribution pipes are adopted in the present invention, which can continuously redistribute the refrigerant medium during operation, which is beneficial to ensuring the uniformity of the heat exchange effect and facilitating the smoother flow of the refrigerant medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to make the object, technical solution and advantages of the present invention clearer, the present invention provides the following drawings for description:

[0019] Figure 1 The front view of the heat exchange core assembly in the embodiment;

[0020] Figure 2 The side view of the heat exchange core assembly in the embodiment;

[0021] Figure 3 The top view of the heat exchange core assembly in the embodiment;

[0022] Figure 4 The structural schematic diagram of a heat exchange unit in the embodiment.

[0023] The markings in the drawings are as follows: flue gas channel 1, elbow section 10, first distribution pipe 11, second distribution pipe 12, heat exchange pipe 2, exhaust valve 3, drain valve 4, baffle 5, high-temperature medium pipe 6. Detailed implementation manners

[0024] Embodiment: As Figures 1-4 shown, a low-temperature economizer heat exchange unit and a heat exchange core assembly include: a plurality of heat exchange pipes 2 arranged side by side, the heat exchange pipes 2 are vertically arranged, the top of each heat exchange pipe 2 is connected to the first distribution pipe 11, an exhaust valve 3 is arranged on the first distribution pipe 11, the bottom of each heat exchange pipe is connected to the second distribution pipe 12, a drain valve 4 is arranged on the second distribution pipe 12, a heat exchange medium inlet and outlet is arranged on the distribution pipe 11, and the refrigerant medium channel is jointly formed by the inner cavity of the first distribution pipe 11, the inner cavity of the second distribution pipe 12 and the inner cavity of the heat exchange pipe 2.

[0025] When high-temperature flue gas passes through the flue gas channel 1, the flue gas is heat-exchanged by introducing liquid (water) into the refrigerant medium channel. The high pressure in the heat exchange pipe 2 will be caused by the vaporization of the coolant in the heat exchange pipe 2. Under the action of high pressure, the gas in the heat exchange pipe 2 can be discharged through the exhaust valve 3 at the top of the heat exchange pipe 2, and the liquid in the heat exchange pipe 2 is discharged through the drain valve 4 at the bottom of the heat exchange pipe 2 to play a role in pressure relief and liquid drainage, thereby reducing the internal pressure of the heat exchange pipe 2 and improving the durability of the heat exchange pipe 2; and a plurality of first distribution pipes 11 and second distribution pipes 12 can uniformly discharge the water vapor in the heat exchange pipe 2, avoiding overheating and water hammer phenomena in local areas and improving the heat exchange effect of the flue gas.

[0026] In one implementation manner, the first distribution pipe 11 and the second distribution pipe 12 are both horizontally arranged, and the centers of the first distribution pipe 11 and the second distribution pipe 12 are not in the same vertical plane, that is, the first distribution pipe 11 and the second distribution pipe 12 are arranged in a staggered manner. This result further expands the distance between adjacent heat exchange pipes 2 and facilitates more sufficient heat exchange.

[0027] In one embodiment, the distribution pipe and the heat exchange pipe are connected through an elbow section 10, and the elbow section 10 is formed by using an elbow or by bending the upper section of the heat exchange pipe, so that the end section of the heat exchange pipe 2 is arranged obliquely, which is convenient for manufacturing.

[0028] In one embodiment, two symmetrically arranged second distribution pipes 12 are used, and two groups of symmetrically arranged heat exchange pipes 2 are used. The symmetry center is the center line of the first distribution pipe 11 in the vertical direction. The heat exchange medium inlet is arranged on one of the second distribution pipes 12, and the heat exchange medium outlet is arranged on the other second distribution pipe 12. The first distribution pipe 11 serves as a heat exchange medium transfer chamber, and the included angle between the two elbow sections connecting the same distribution pipe is 20° to 90°. Figure 1 Only the included angle of 60° between the two elbow sections connecting the same distribution pipe is schematically shown.

[0029] A heat exchange core assembly of a low-temperature economizer heat exchange unit includes connecting a plurality of the low-temperature economizer heat exchange units in series, and the refrigerant medium channels of the low-temperature economizer heat exchange units are communicated. The lower ends of the heat exchange pipes 2 of adjacent low-temperature economizer heat exchange units share the same second distribution pipe 12, and the refrigerant medium channel serves as a flue gas channel 1. A baffle 5 is arranged in the flue gas channel 1 and on the flue gas inlet side, and the baffle 5 is used to open or close the flue gas channel 1.

[0030] In this solution, the baffle 5 is slidably installed in the flue gas channel 1, and sliding the baffle 5 can open or close the flue gas channel 1; or a method of rotating to open the flue gas channel 1 can be adopted, such as the baffle 5 is rotatably installed in the flue gas channel 1, and rotating the baffle 5 can open or close the flue gas channel 1. A high-temperature medium pipe 6 is arranged between adjacent low-temperature economizer heat exchange units, and the high-temperature medium pipe 6 is externally connected to a high-temperature medium supply system to enable high-temperature medium to be introduced into the flue gas channel 1; wherein, multiple groups of heat exchange core assemblies are arranged side by side, and each group of heat exchange core assemblies is equipped with the baffle 5 and the high-temperature medium pipe 6. During normal flue gas exhaust, the baffle 4 needs to be in an open state; when it is necessary to clean the ash adhered to the outer wall of the heat exchange pipe 2, the baffle 4 needs to be in a closed state first, and then high-temperature medium (such as high-pressure gas or high-temperature steam) is introduced, and the high-temperature medium is used to increase the wall temperature of the heat exchange pipe 2, so as to vaporize the ammonium bisulfate adhering to the pipe wall.

[0031] This solution can not only effectively alleviate the ash fouling on the heat exchange core of the low-temperature economizer, but also eliminate the need for soot blowers and facilitate the timely removal of water vapor in the heat exchange tubes. During use, the gas in the heat exchange tubes is discharged through the exhaust valves, and the accumulated water in the heat exchange tubes is discharged through the drain valves, so as to play the role of draining water and gas, improving the durability and safety of the heat exchange tubes. Multiple exhaust valves and drain valves are provided, which can evenly and fully discharge the water vapor in multiple parts of the heat exchange tubes, avoiding overheating and water hammer phenomena in local areas and improving the heat exchange effect of the flue gas. In addition, this solution uses multiple distribution pipes, which can continuously redistribute the refrigerant medium during operation, helping to ensure the uniformity of the heat exchange effect and facilitating smoother flow of the refrigerant medium.

Claims

1. A low-temperature economizer heat exchange unit, comprising a plurality of heat exchange tubes (2) arranged side by side, characterized in that: The heat exchange tubes (2) are arranged vertically, the top of each heat exchange tube (2) is connected to a first distribution tube (11), and the first distribution tube (11) is provided with an exhaust valve (3); the bottom of each heat exchange tube (2) is connected to a second distribution tube (12), and the second distribution tube (12) is provided with a drain valve (4); a heat exchange medium inlet and outlet are provided on the distribution tubes, and a refrigerant medium channel is formed by the inner cavity of the first distribution tube (11), the inner cavity of the second distribution tube (12), and the inner cavity of the heat exchange tube (2).

2. The low-temperature economizer heat exchange unit according to claim 1, characterized in that: The first distribution pipe (11) and the second distribution pipe (12) are arranged horizontally.

3. The low-temperature economizer heat exchange unit according to claim 2, characterized in that: The center of the first distribution pipe (11) and the center of the second distribution pipe (12) are located on different vertical planes.

4. The low-temperature economizer heat exchange unit according to any one of claims 1 to 3, characterized in that: The distribution pipe is connected to the heat exchange pipe (2) via a bent pipe section (10), and the bent pipe section (10) is formed by using an elbow or by bending the upper section of the heat exchange pipe (2) to achieve an oblique arrangement of the end sections of the heat exchange pipe (2).

5. The low-temperature economizer heat exchange unit according to claim 4, characterized in that: Two symmetrically arranged second distribution pipes (12) are used, two groups of symmetrically arranged heat exchange pipes (2) are used, the center of symmetry is the center line of the first distribution pipe (11) in the vertical direction, the heat exchange medium inlet is arranged on one of the second distribution pipes (12), the heat exchange medium outlet is arranged on the other second distribution pipe (12), and the first distribution pipe (11) serves as a heat exchange medium transfer chamber; the angle between the two curved pipe sections (10) connecting the same distribution pipe is 20 to 90 degrees.

6. A heat exchange core assembly using the low-temperature economizer heat exchange unit according to any one of claims 1 to 5, characterized in that: A plurality of the low-temperature economizer heat exchange units are connected in series, and the refrigerant medium channels of all the low-temperature economizer heat exchange units are connected.

7. The heat exchange core assembly according to claim 6, characterized in that: The lower ends of the heat exchange tubes (2) of adjacent low-temperature economizer heat exchange units share the same second distribution pipe (12).

8. The heat exchange core assembly according to claim 7, characterized in that: The outside of the tube of the low-temperature economizer heat exchange unit serves as a flue gas passage; a damper door (5) is provided in the flue gas passage and at the flue gas inlet side, and the damper door (5) is used to open or close the flue gas passage.

9. The heat exchange core assembly according to claim 8, characterized in that: A high-temperature medium pipe (6) is provided between adjacent low-temperature economizer heat exchange units, and the high-temperature medium pipe (6) is externally connected to a high-temperature medium supply system so as to enable the high-temperature medium to be introduced into the flue gas channel.

10. The heat exchange core assembly according to claim 9, characterized in that: A plurality of groups of heat exchange core assemblies are arranged side by side, and each group of heat exchange core assemblies is provided with the baffle door (5) and the high-temperature medium pipe (6).

Images