Anti-blocking system and anti-blocking method for rotary heat exchanger based on split-ring cyclic heating

Abstract

The invention discloses a rotary heat exchanger anti-blocking system and anti-blocking method based on ring-splitting cyclic heating. The cold end face of the heat exchanger rotor is divided into N concentric rings by a circumferential partition plate, N≥2, and N special-shaped cold medium pipes are arranged at the cold end of at least one cold medium compartment. One end of the special-shaped cold medium pipe is a fan-shaped opening and the other end is a rectangular opening. Each fan-shaped opening is arranged in a one-to-one correspondence with the concentric rings. The radial edges on both sides of the fan-shaped opening are connected to the side edges of the cold end fan-shaped plate in the corresponding concentric ring, and the plane where the fan-shaped opening is located is flush with the sealing surface of the cold end fan-shaped plate; each rectangular opening is provided with an automatic regulating door that can adjust the flow rate of the cold medium. The flow rate of the cold medium in each special-shaped cold medium pipe is reduced by cyclically, and the wall temperature of the heat storage element in the corresponding concentric ring is increased, so that the condensed or crystallized material adhering thereto is gradually vaporized and discharged from the heat exchanger rotor along with the hot medium, thereby effectively solving the blockage and corrosion problems of the rotary heat exchanger.

Description

Technical Field

[0001] The invention relates to a rotary heat exchanger anti-blocking system and anti-blocking method based on split-ring cyclic heating, belonging to the technical field of industrial heat exchangers. Background Art

[0002] A rotary heat exchanger is a heat storage heat exchanger, which belongs to rotating equipment. The rotating part is called the heat exchanger rotor, which is also the heat storage part of this heat exchanger. Rotary heat exchangers are used to recover the heat of high-temperature gas and are widely used in industrial energy conservation. The working medium is divided into cold medium and hot medium. Generally, the two flow in reverse in the heat exchanger rotor, and heat exchange is achieved through the heat storage of the heat exchanger rotor.

[0003] The above-mentioned high-temperature gas is generally high-temperature flue gas. When heat is transferred to the cold medium, the temperature of the flue gas also decreases. In this process, condensed or even crystallized substances may be produced in the flue gas. In addition, the flue gas contains dust, which can easily cause blockage and corrosion of the heat storage element in the heat exchanger rotor.

[0004] The rotary air preheater used in the field of coal-fired power generation is a specific type of rotary heat exchanger. It is generally a three-compartment or four-compartment structure, including a primary air compartment, a secondary air compartment and a flue gas compartment. It uses the heat of high-temperature flue gas to heat the air, thereby realizing energy recovery. However, after the flue gas temperature drops, the SO3 in the flue gas reacts with the NH3 that escapes from the upstream denitrification to form ammonium bisulfate (NH4HSO4), which is liquid in the range of 146 to 207°C and adheres to the surface of the thermal storage element together with the coal fly ash; when the temperature drops further, SO3 also reacts with the water vapor in the flue gas to form liquid sulfuric acid (H2SO4), causing low-temperature corrosion, further exacerbating the blockage and corrosion problems of the thermal storage element.

[0005] The flue gas reheater used for denitrification in the steel industry is also a specific type of rotary heat exchanger. It is generally a two-compartment structure, including clean flue gas and raw flue gas compartments. It uses the heat of high-temperature flue gas (clean flue gas) to heat low-temperature flue gas (raw flue gas) to increase the temperature of the raw flue gas to meet the requirements of denitrification. After denitrification, the heat is recovered to achieve energy saving. In the application of flue gas reheaters, there are similar problems as the above-mentioned rotary air preheaters, which affect the safety and economy of equipment operation. Summary of the invention

[0006] In order to solve the problems of blockage, corrosion and the like existing in the rotary heat exchanger in the prior art, the present invention provides a rotary heat exchanger anti-blockage system and anti-blockage method based on split-ring cyclic heating.

[0007] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0008] A rotary heat exchanger anti-blocking system based on ring-splitting cyclic heating, the cold end face of the heat exchanger rotor is divided into N concentric rings by a circumferential partition, N ≥ 2, N special-shaped cold medium pipes are arranged at the cold end of at least one cold medium compartment, one end of the special-shaped cold medium pipe is a fan-shaped opening, and the other end is a rectangular opening, each fan-shaped opening is arranged in a one-to-one correspondence with the concentric rings, the radial edges on both sides of the fan-shaped opening are connected to the side edges of the cold end fan-shaped plate in the corresponding concentric ring, and the plane where the fan-shaped opening is located is flush with the sealing surface of the cold end fan-shaped plate; each rectangular opening is provided with an automatic adjustment door that can adjust the flow of the cold medium.

[0009] The rotary heat exchanger is divided into at least two compartments, and at least one hot medium compartment and one cold medium compartment.

[0010] The “fan-shaped” in the present application includes a figure formed by two arcs with the same bending direction and two radial edges connecting the two ends of the two arcs.

[0011] The special-shaped cold medium pipe gradually transitions from a fan-shaped opening at one end to a rectangular opening at the other end.

[0012] A method for preventing blockage of a rotary heat exchanger based on ring-by-ring cyclic heating, which cyclically reduces the flow rate of cold medium in various special-shaped cold medium pipelines, increases the wall temperature of heat storage elements in corresponding concentric rings, and gradually vaporizes condensed or crystallized materials adhering thereto, and is discharged from the heat exchanger rotor along with the hot medium, thereby preventing blockage.

[0013] The applicant has found through research that when the flow rate in a certain special-shaped cold medium pipeline is adjusted to be reduced, the wall temperature of the heat storage element in the corresponding concentric ring rises, and the condensed or crystallized material adhering thereto gradually vaporizes and is discharged from the heat exchanger rotor along with the hot medium, thereby effectively solving the blockage and corrosion problems of the rotary heat exchanger. The present application utilizes a specific structural component, namely, a key component that cooperates with the fan-shaped port and the annular cavity on the cold end face of the heat exchanger rotor, to achieve the first regional cyclic heating of the heat storage element in the rotating state in the industry. When the flow rate in a certain special-shaped cold medium pipeline is reduced, the flow rate of other special-shaped cold medium pipelines is increased accordingly. The flow rate in each special-shaped cold medium pipeline is cyclically reduced through the automatic control system, and the total flow rate is kept basically unchanged, thereby meeting the process requirements of the industrial field system. When the flow rate in a certain special-shaped cold medium pipeline is controlled to be smaller, the wall temperature of the heat storage element in the corresponding concentric ring rises more, and the anti-blockage and anti-corrosion effect is better. In addition, the longer the heating time, the more significant the anti-blockage and anti-corrosion effect. Of course, the greater the temperature rise and the longer the temperature rise time, the greater the energy consumption. In practical applications, the temperature rise and the temperature rise time can be selected according to the situation.

[0014] In order to improve the sealing performance at the junction of the sector-shaped opening and the concentric ring, a T-shaped sealing surface is provided at the sector-shaped opening that is connected to the arcuate edge of the concentric ring.

[0015] In order to further improve the sealing performance at the junction of the fan-shaped opening and the concentric ring and facilitate on-site adjustment, a circumferential seal is provided on the circumferential partition plate. The circumferential seal is clamped at the end of the circumferential partition plate by bolts to facilitate on-site adjustment of the sealing gap.

[0016] In order to improve the integration of the system, all of the above-mentioned automatic adjustment doors are assembled into an integrated structure, such as using a multi-channel plug-in door.

[0017] The rotary heat exchanger can be a two-compartment structure, a three-compartment structure or a four-compartment structure. When it is a two-compartment structure, the cold medium and the hot medium flow from one compartment respectively; when it is a structure with more than two compartments, the cold medium flows from multiple compartments, and N special-shaped cold medium pipes are respectively set for the pipes connecting one or more cold medium compartments.

[0018] As one specific implementation scheme, when there are more than two cold medium compartments, N special-shaped cold medium pipes are respectively provided at the cold ends of the more than two cold medium compartments.

[0019] In order to grasp the effect of the sub-ring cyclic heating, the above-mentioned anti-blocking system also includes N temperature measuring points, and the N temperature measuring points are respectively arranged in N concentric rings facing the cold end of the heat medium compartment.

[0020] In order to reduce costs and ensure operating results and system safety, preferably, N is between 3 and 5, that is, N is preferably 3 or 4 or 5.

[0021] The present invention combines the existing automatic control system and driving device to realize automatic control.

[0022] The technologies not mentioned in the present invention are all referred to the prior art.

[0023] The present invention is based on a rotary heat exchanger anti-blocking system with split-ring cyclic heating. The cold end face of the heat exchanger rotor is divided into N concentric rings by a circumferential partition. At the same time, each concentric ring corresponding to the cold medium compartment is connected to a special-shaped cold medium pipeline. When the flow in a special-shaped cold medium pipeline is adjusted to reduce, the wall temperature of the heat storage element in the corresponding concentric ring rises, and the condensed or crystallized material adhering to it gradually vaporizes and is discharged from the heat exchanger rotor along with the hot medium, effectively solving the blockage and corrosion problems of the rotary heat exchanger. The split-ring design reduces the disturbance of the medium flow, improves the safety of equipment operation, and significantly improves the economic efficiency of operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the anti-blocking system of the rotary heat exchanger based on the split-ring cyclic heating of the present invention.

[0025] Figure 2 It is a schematic diagram of the sealing structure at the junction of the sector-shaped opening and the concentric rings in the present invention.

[0026] Figure 3 for Figure 1 The A-direction view in the middle shows the structural features of the cold end face of the heat exchanger rotor.

[0027] Figure 4 for Figure 1 The B-direction view in the middle shows the structural features of the special-shaped cold medium pipes of the two-compartment heat exchanger.

[0028] Figure 5 for Figure 1 The middle B view shows the structural features of the special-shaped cold medium pipe of the three-compartment heat exchanger.

[0029] In the figure: 1 is a circumferential partition, 2 is a special-shaped cold medium pipeline, 3 is an automatic adjustment door, 4 is a fan-shaped opening, 5 is a T-shaped sealing surface, 6 is a circumferential seal, 7 is a temperature measuring point; 10 is the flow direction of the cold medium, and 11 is the flow direction of the hot medium. DETAILED DESCRIPTION

[0030] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0031] Example 1

[0032] like Figure 1 , 3 As shown in Figure 4, a rotary heat exchanger anti-blocking system based on ring-type cyclic heating is specifically applied to a flue gas reheater with two compartments, wherein a hot medium compartment (for circulating clean flue gas) and a cold medium compartment (for circulating original flue gas) are respectively provided; the cold end face of the heat exchanger rotor is divided into three concentric rings by a circumferential partition plate, and three special-shaped cold medium pipes are provided at the cold end of the cold medium compartment, wherein one end of the special-shaped cold medium pipe is a fan-shaped opening and the other end is a rectangular opening, and the special-shaped cold medium pipe gradually transitions from the fan-shaped opening at one end to the other end. A rectangular opening is formed, and each fan-shaped opening is arranged in one-to-one correspondence with the concentric rings. The radial edges on both sides of the fan-shaped opening are connected to the side edges of the cold end fan-shaped plate in the corresponding concentric ring, and the plane where the fan-shaped opening is located is flush with the sealing surface of the cold end fan-shaped plate; each rectangular opening is provided with an automatic regulating door that can adjust the flow rate of the cold medium, which reduces the flow rate of the cold medium in each special-shaped cold medium pipeline by cycle, increases the wall temperature of the heat storage element in the corresponding concentric ring, and gradually vaporizes the condensed or crystallized material adhering thereto, and is discharged from the heat exchanger rotor along with the hot medium, thereby achieving anti-blocking.

[0033] The applicant has found through research that when the flow rate in a certain special-shaped cold medium pipeline is adjusted to reduce, the wall temperature of the heat storage element in the corresponding concentric ring rises, and the condensed or crystallized material adhering thereto gradually vaporizes and is discharged from the heat exchanger rotor along with the hot medium, thereby effectively solving the blockage and corrosion problems of the rotary heat exchanger. When the flow rate in a certain special-shaped cold medium pipeline is reduced, the flow rate of other special-shaped cold medium pipelines increases accordingly. The flow rate in each special-shaped cold medium pipeline is reduced in turn through the automatic control system, and the total flow rate is kept basically unchanged, thereby meeting the process requirements of the industrial field system. When the flow rate in a certain special-shaped cold medium pipeline is controlled to be smaller, the wall temperature of the heat storage element in the corresponding concentric ring increases, and the anti-blockage and anti-corrosion effect is better. In addition, the longer the heating time is, the more significant the anti-blockage and anti-corrosion effect is. Of course, the larger the heating range and the longer the heating time is, the greater the energy consumption is. In actual applications, the heating range and heating time can be selected according to the situation.

[0034] Example 2

[0035] On the basis of Example 1, the following improvements were made: Figure 2 As shown, in order to improve the sealing performance at the junction of the sector-shaped opening and the concentric ring, a T-shaped sealing surface is provided at the sector-shaped opening connected to the arcuate edge of the concentric ring.

[0036] Example 3

[0037] On the basis of Example 2, the following improvements were made: Figure 2 As shown, in order to further improve the sealing performance at the junction of the fan-shaped opening and the concentric ring and facilitate on-site adjustment, a circumferential seal is provided on the above-mentioned circumferential partition, and the circumferential seal is clamped at the end of the circumferential partition by bolts to facilitate on-site adjustment of the sealing gap.

[0038] Example 4

[0039] On the basis of Example 3, the following improvements were made: Figure 2 As shown, in order to improve the integration of the system, all the automatic adjustment doors are assembled into an integrated structure, such as using multi-channel plug-in doors.

[0040] Example 5

[0041] On the basis of Example 3, the following improvements were made: Figure 1 As shown, in order to grasp the effect of the sub-ring cyclic heating, the anti-blocking system also includes three temperature measuring points, and the three temperature measuring points are respectively arranged in N concentric rings facing the cold end of the heat medium compartment.

[0042] Example 6

[0043] like Figure 5As shown, the difference from Example 5 is that: a rotary heat exchanger anti-blocking system based on split-ring cyclic heating is specifically applied to a three-compartment air preheater, and a hot medium compartment (flowing flue gas) and two cold medium compartments (flowing primary air and secondary air) are respectively set, and only three special-shaped cold medium pipes are set at the cold end of one of the cold medium compartments (usually the secondary air compartment). Of course, three special-shaped cold medium pipes can also be set at the cold ends of the two cold medium compartments according to the on-site conditions.

[0044] Through engineering practice, the above-mentioned anti-blocking systems for rotary heat exchangers based on split-ring cyclic heating have effectively solved the blockage and corrosion problems of rotary heat exchangers. The split-ring design reduces the disturbance of medium flow, improves the safety of equipment operation, and significantly improves the operating economy.

Claims

1. A rotary heat exchanger anti-blocking system based on split-ring cyclic heating, characterized in that: The cold end face of the heat exchanger rotor is divided into N concentric rings by a circumferential partition plate, N ≥ 2, and N special-shaped cold medium pipes are arranged at the cold end of at least one cold medium compartment, one end of the special-shaped cold medium pipe is a fan-shaped opening, and the other end is a rectangular opening, each fan-shaped opening is arranged one-to-one with the concentric rings, and the radial edges on both sides of the fan-shaped opening are connected to the side edges of the cold end fan-shaped plate in the corresponding concentric ring, and the plane where the fan-shaped opening is located is flush with the sealing surface of the cold end fan-shaped plate; each rectangular opening is provided with an automatic regulating door that can adjust the flow of the cold medium; By cyclically reducing the flow of cold medium in various special-shaped cold medium pipelines, the wall temperature of the heat storage element in the corresponding concentric ring is increased to prevent blockage.

2. The anti-blocking system for rotary heat exchanger based on split-ring cyclic heating as claimed in claim 1 is characterized in that: A T-shaped sealing surface is arranged at the sector-shaped opening connected with the arc-shaped edge of the concentric ring.

3. The anti-blocking system for rotary heat exchanger based on split-ring cyclic heating as claimed in claim 1 or 2, characterized in that: A circumferential seal is arranged on the circumferential partition, and the circumferential seal is clamped at the end of the circumferential partition by bolts.

4. The anti-blocking system for rotary heat exchanger based on ring-by-ring heating as claimed in claim 1 or 2, characterized in that: All the automatic regulating doors are assembled into an integrated structure.

5. The anti-blocking system for rotary heat exchanger based on split-ring cyclic heating as claimed in claim 1 or 2, characterized in that: When there are more than two cold medium compartments, N special-shaped cold medium pipes are respectively arranged at the cold ends of the two or more cold medium compartments.

6. The anti-blocking system for rotary heat exchanger based on ring-by-ring heating as claimed in claim 1 or 2, characterized in that: It also includes N temperature measuring points, which are respectively arranged in N concentric rings facing the cold end of the heat medium compartment.

7. The anti-blocking system for rotary heat exchanger based on split-ring cyclic heating as claimed in claim 1 or 2, characterized in that: N is between 3 and 5.

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