Anti-fouling and anti-blocking online descaling device for tubular heat exchange equipment and descaling method of anti-fouling and anti-blocking online descaling device

Abstract

The invention discloses an anti-fouling and anti-blocking online descaling device for tubular heat exchange equipment and a descaling method thereof, and relates to the technical field of petrochemical engineering, the anti-fouling and anti-blocking online descaling device comprises a tubular heat exchange tube, a scale scraping assembly is arranged outside the heat exchange tube, and the scale scraping assembly comprises a supporting plate far away from one end of the heat exchange tube and a plurality of scale scraping plates arranged on the heat exchange tube in a sleeving mode; one side, deviating from the heat exchange tube, of the supporting plate is connected with the rigid shaft; the outer side of the rigid shaft is connected with a reciprocating motion mechanical unit; through the reciprocating motion mechanical unit, the scraping assembly is guided to do reciprocating motion, and online descaling of the heat exchange equipment is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of petrochemical industry, in particular to an online descaling device for shell-and-tube heat exchange equipment with anti-fouling and clogging resistance and a descaling method thereof. Background Art

[0002] Shell-and-tube heat exchangers are widely used in the fields of petroleum, coal chemical industry, and environmental sewage treatment. They can be used as reboilers in distillation unit operations, heating chambers in evaporation operations, and heat exchangers between liquids and liquids or between liquids and gases. Especially in the process of handling non-clean systems that are prone to fouling, shell-and-tube heat exchange has always been the preferred method of engineering design because the shells are simple to make and easy to clean.

[0003] However, although the anti-fouling and clogging ability of the shell and tube heat exchanger is very outstanding compared with plate exchange, winding tube, spiral plate, etc., it is still very easy to be blocked for high-pollution systems, such as wastewater generated in coking and coal gasification. In mild cases, the heat transfer efficiency is reduced, and the energy consumption of the equipment is sharply increased. In severe cases, the heat exchanger will be directly blocked within ten days, affecting the normal operation of the equipment and even the entire system. Therefore, the blockage problem of the heat exchanger is not only related to energy waste, but in some industries, it has even become a major bottleneck in the development of the industry; there are three popular anti-scaling technologies at present. One is to use chemical methods to perform online descaling by adding chemical agents. This method is relatively expensive and can only alleviate the blockage state and relatively extend the service life of the heat exchanger. The addition of chemical agents will change the composition of the system, so its application is greatly limited. The second is to add plug-ins in the tube, such as spiral wires, spring wires, etc., or to change the flow state of the liquid in the tube, or to use the relative movement of the plug-in and the tube wall to perform descaling. This method belongs to the passive online descaling method, that is, no additional power is added. However, for high-fouling systems, this method will not only fail to achieve the purpose of descaling, but will also increase the difficulty of cleaning the dirt in the later stage. The third descaling method is mechanical descaling. This method requires the equipment to stop running and can only be operated during the maintenance period. Generally, acid cleaning, alkali cleaning or high-pressure water guns, or mechanical methods are used to physically clean the tube side scale layer in the shell and tube heat exchanger tubes by manpower (due to the structural limitations of the shell and tube heat exchanger, it is difficult to achieve mechanical cleaning on the shell side) to achieve the purpose of cleaning the heat exchanger;

[0004] Disadvantages of existing technology:

[0005] 1. The reagent addition method will add extra chemical reagents to the system on the one hand, and increase the operating cost on the other hand. The most important thing is that it cannot fundamentally solve the blockage problem. For high-pollution systems, it can only slow down the blockage cycle to a certain extent;

[0006] 2. Passive online descaling can only descaling relatively clean systems flowing in the pipe, and has no effect on highly polluted systems, and will also increase the difficulty of manual descaling in the later stage;

[0007] 3. The mechanical descaling method requires the heat exchanger to be shut down and then the heat exchange tubes to be cleaned one by one, which seriously affects the normal operation of the equipment. At the same time, this method has high work intensity, long cleaning cycle and great safety hazards;

[0008] Regardless of the method, existing technologies bring huge time costs and economic burdens to corporate production. Summary of the invention

[0009] In view of the deficiencies in the prior art, the present invention provides an online descaling device for shell-and-tube heat exchange equipment and a descaling method thereof that are resistant to fouling and clogging, so as to solve the technical bottleneck of reduced heat exchange efficiency and heat exchanger clogging caused by fouling in the heat exchange device during the existing heat exchange process.

[0010] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0011] An online descaling device for shell-and-tube heat exchange equipment that resists fouling and clogging comprises a shell-and-tube heat exchange tube (13), wherein a scraper assembly (3) is arranged outside the heat exchange tube (13), and the scraper assembly (3) comprises a support plate (301) away from one end of the heat exchange tube (13), and a plurality of scraper plates (306) sleeved on the heat exchange tube (13); the plurality of scraper plates (306) are arranged at equal intervals and divided into two layers, which are vertically staggered and arranged; the upper parts of the scraper plates (306) of the upper layer are fixedly connected to the support plate (301) through a tie rod 1 (302) penetrating the upper scraper plates (306); the lower parts of the scraper plates (306) of the lower layer are fixedly connected to the support plate (301) through a tie rod 2 (305) penetrating the lower scraper plates (306); the end of the tie rod 1 (302) away from the support plate (301) is connected to the upper layer farthest from the support plate (301); 1), the end of the pull rod 2 (305) away from the support plate (301) is fixedly connected to the scraper plate (306) of the lower layer farthest from the support plate (301); the adjacent scraper plates (306) of the upper layer are separated by a spacing tube 1 (304) sleeved on the pull rod 1 (302); the adjacent scraper plates (306) of the lower layer are separated by a spacing tube 2 (307) sleeved on the pull rod 2 (305); the lower part of the scraper plates (306) of the upper layer and the upper part of the scraper plates (306) of the lower layer are also connected by a spacing rod (303) that runs through all the scraper plates (306), and the spacing rod (303) is fixedly connected to the support plate (301); the side of the support plate (301) away from the heat exchange tube (13) is connected to the rigid shaft (7); the outer side of the rigid shaft (7) is connected to a reciprocating mechanical unit (9).

[0012] Preferably, a plate hole is opened on the scraper plate (306), and the plate hole is sleeved on the heat exchange tube (13). The matching deviation between the plate hole and the heat exchange tube (13) is that the inner diameter of the plate hole is the outer diameter of the heat exchange tube (13) + 0 to 0.2 mm.

[0013] Preferably, the movement stroke distance of all the scraping plates (306) in the scraping assembly (3) is consistent with the movement stroke provided by the reciprocating mechanical unit (9);

[0014] Preferably, the number of scraper plates (306) is greater than the quotient of the length of the heat exchange tube (13) and the movement stroke distance.

[0015] The present invention also provides a reboiler including the above-mentioned online descaling device, further comprising a shell (4), wherein a cleaning body inlet (1) is provided on the upper surface of one end of the shell (4), the cleaning body inlet (1) is connected to one end of a heat exchange tube (13) in the online descaling device, and the other end of the heat exchange tube (13) is connected to a cleaning body outlet (15) provided on the lower surface of the shell (4), and the cleaning body runs through the tube during the heat exchange process; a high-contaminant system inlet (2) is also provided on the upper surface of the shell (4), and a contaminant outlet (10) and a dirt outlet (11) are provided on the bottom surface of the shell (4); during the heat exchange process, high-contaminants run through the shell; and a gas phase outlet (5) is also provided on the upper surface of the shell (4).

[0016] Preferably, the heat exchange tube (13) is located inside the shell (4), and its inlet and outlet ends are fixedly connected to the shell (4) via a partition (14), and the partition (14) divides the reboiler into a tube-side part and a shell-side part.

[0017] Preferably, the bottom of the partition (14) is fixedly connected to the bottom of the support plate (301) via a horizontal guide rail (12); the scraper assembly (3) can reciprocate along the guide rail (12) within the length of the heat exchange tube (13) under the action of the reciprocating mechanical unit (9).

[0018] Preferably, the reciprocating mechanical unit (9) is arranged outside the reboiler and connected to the rigid shaft (7) via an axle pin (8); the rigid shaft (7) is connected to the scraper assembly (3) inside the shell (4); a mechanical sealing device is used at the position where the rigid shaft (7) enters and exits the shell (4) to ensure that the medium in the shell (4) does not leak.

[0019] The present invention also provides a method for online descaling of the above reboiler, comprising the following steps:

[0020] Step 1: The clean material system goes through the tube side, enters the heat exchange tube (13) from the clean body inlet (1), and flows out from the clean body outlet (15) after heat exchange; the high-pollutant material goes through the shell side, enters the shell (4) from the high-pollutant system inlet (2), and flows out of the heat exchanger from the polluted material outlet (10) after heat exchange;

[0021] Step 2: When the dirt is attached to the outer surface of the heat exchange tube (13) due to the heat, the reciprocating mechanical unit (9) is started, and the scraping component (3) can reciprocate within the length of the heat exchange tube (13) under the action of the reciprocating mechanical unit (9);

[0022] Step 3: The slow movement of the scraping assembly (3) increases the turbulence of the dirt between two adjacent scraping plates (306), thereby delaying the formation of the scale layer;

[0023] Step 4: When the scale layer gradually forms, thickens, and eventually exceeds the gap between the scraper plate (306) and the heat exchange tube (13), the scale layer exceeding the gap distance will be promptly cleaned by the moving scraper plate (306), thereby separating from the heat exchange tube (13) and, under the action of liquid turbulence and gravity, deposited at the bottom of the shell (4), and cleaned and discharged from the dirt outlet (11).

[0024] The present invention provides an online descaling device for shell-and-tube heat exchange equipment and a descaling method thereof that are resistant to fouling and clogging, and has the following beneficial effects:

[0025] By adding a mechanical mechanism in the shell space to guide the scraper assembly to reciprocate, online descaling of the heat transfer device is achieved. It can ensure that the heat exchange equipment always maintains a relatively high heat transfer efficiency. Especially when dealing with high-dirt systems, it can ensure the stable and continuous operation of the heat exchange equipment for a long time; relatively clean or clean systems go through the tube path, which can increase the operating cycle of the heat exchange equipment and facilitate the cleaning of dirt in the tube; the scraper assembly uses multiple plates in series to divide the heat exchange tube into multiple sections, so that the motion machine can achieve descaling within the entire length of the straight tube section heat exchange tube within a shorter motion stroke; the reciprocating motion of the scraper assembly can, on the one hand, achieve online descaling of the heat exchange tube path, and on the other hand, it can also disturb the fluid to achieve the purpose of enhancing heat transfer. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0027] Figure 2 This is a single motion stroke position limit diagram of the scraping assembly of the present invention.

[0028] In the figure, 1, cleaning body inlet; 2, high dirt system inlet; 3, scraper assembly; 4, shell; 5, gas phase outlet; 6, mechanical seal; 7, rigid shaft; 8, shaft pin; 9, reciprocating mechanical unit; 10, dirt outlet; 11, dirt outlet; 12, guide rail; 13, heat exchange tube; 14, partition; 15, cleaning body outlet; 301, support plate; 302, pull rod one; 303, distance rod; 304, distance tube one; 305, pull rod two; 306, scraper plate; 307, distance tube two. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0030] See also Figure 1-2 An embodiment of the present invention provides a reboiler including an online descaling device for shell-and-tube heat exchange equipment that resists fouling and clogging, comprising a shell (4), a shell-and-tube heat exchange tube (13) being arranged inside the shell, a scraper assembly (3) being arranged outside the heat exchange tube (13), the inlet and outlet ends of the heat exchange tube (13) being fixedly connected to the shell (4) via a partition (14), and the partition (14) dividing the reboiler into a tube-side portion and a shell-side portion. A cleaning body inlet (1) is provided on the upper surface of one end of the shell (4), the cleaning body inlet (1) is connected to one end of a heat exchange tube (13) in an online descaling device, the other end of the heat exchange tube (13) is connected to a cleaning body outlet (15) provided on the lower surface of the shell (4), and the cleaning body inlet (1) and the cleaning body outlet (15) are not connected; during the heat exchange process, the cleaning body runs through the tube path; the upper surface of the shell (4) is also provided with a high-contamination system inlet (2), and the bottom surface of the shell (4) is provided with a contaminant outlet (10) and a dirt outlet (11); during the heat exchange process, high-contamination runs through the shell path; the upper surface of the shell (4) is also provided with a gas phase outlet (5).

[0031] The scraper assembly (3) comprises a support plate (301) away from one end of the heat exchange tube (13), and a plurality of scraper plates (306) sleeved on the heat exchange tube (13); the plurality of scraper plates (306) are arranged at equal intervals and are divided into two layers, which are vertically staggered and arranged; the upper portions of the scraper plates (306) of the upper layer are fixedly connected to the support plate (301) via a tie rod 1 (302) penetrating the upper scraper plates (306); the lower portions of the scraper plates (306) of the lower layer are fixedly connected to the support plate (301) via a tie rod 2 (305) penetrating the lower scraper plates (306); the end of the tie rod 1 (302) away from the support plate (301) is fixedly connected to the scraper plate (306) of the upper layer which is farthest from the support plate (301); the end of the tie rod 1 (302) away from the support plate (301) is fixedly connected to the scraper plate (306) of the upper layer which is farthest from the support plate (301); the end of the tie rod 2 (305) away from the support plate One end of the support plate (301) is fixedly connected to the scraper plate (306) of the lower layer which is farthest from the support plate (301); the adjacent scraper plates (306) of the upper layer are separated by a spacing tube (304) sleeved on the pull rod (302); the adjacent scraper plates (306) of the lower layer are separated by a spacing tube (307) sleeved on the pull rod (305); the lower part of the scraper plates (306) of the upper layer and the upper part of the scraper plates (306) of the lower layer are also connected by a spacing rod (303) which runs through all the scraper plates (306), and the spacing rod (303) is fixedly connected to the support plate (301); the side of the support plate (301) facing away from the heat exchange tube (13) is connected to the rigid shaft (7); the outer side of the rigid shaft (7) is connected to a reciprocating mechanical unit (9). The scraper plate (306) has a plate hole, and is sleeved on the heat exchange tube (13) through the plate hole. The matching deviation between the plate hole and the heat exchange tube (13) is that the inner diameter of the plate hole is the outer diameter of the heat exchange tube (13) + 0 to 0.2 mm. The manufacturing method of the heat exchanger baffle in GB151 can be referred to.

[0032] The movement stroke distance of all the scraping plates (306) in the scraping assembly (3) is consistent with the movement stroke provided by the reciprocating motion mechanical unit (9); Figure 2 As shown, when the scraper assembly (3) reciprocates between the left and right extreme positions, the distance traveled by each scraper plate (306) is the stroke distance that the reciprocating motion mechanical unit (9) can provide. Therefore, when the number of scraper plates (306) is greater than the quotient of the length of the heat exchange tube (13) and the motion stroke distance, the scraper assembly (3) can achieve the scraping and descaling effect on the entire heat exchange tube (13).

[0033] The bottom of the partition (14) is fixedly connected to the bottom of the support plate (301) via a horizontal guide rail (12); the scraper assembly (3) can reciprocate along the guide rail (12) within the length of the heat exchange tube (13) under the action of the reciprocating mechanical unit (9).

[0034] The reciprocating mechanical unit (9) is arranged outside the reboiler and connected to the rigid shaft (7) via a shaft pin (8). The rigid shaft (7) is connected to the scraper assembly (3) inside the shell (4). A mechanical sealing device is used at the position where the rigid shaft (7) enters and exits the shell (4) to ensure that the medium in the shell (4) does not leak.

[0035] Working principle: The method for online descaling of the reboiler includes the following steps:

[0036] Step 1: The clean material system goes through the tube side, enters the heat exchange tube (13) from the clean body inlet (1), and flows out from the clean body outlet (15) after heat exchange; the high-pollutant material goes through the shell side, enters the shell (4) from the high-pollutant system inlet (2), and flows out of the heat exchanger from the polluted material outlet (10) after heat exchange;

[0037] During the heat exchange process, the dirt will adhere to the outer surface of the heat exchange tube (13) due to the heat. If it is not cleaned immediately, the dirt will accumulate over time to form a scale layer, which will not only seriously affect the heat transfer effect, but also block the flow channel of the liquid.

[0038] Step 2: When the dirt is attached to the outer surface of the heat exchange tube (13) due to the heat, the reciprocating mechanical unit (9) is started, and the scraping component (3) can reciprocate within the length of the heat exchange tube (13) under the action of the reciprocating mechanical unit (9);

[0039] Step 3: The slow movement of the scraping assembly (3) increases the turbulence of the dirt between two adjacent scraping plates (306), thereby delaying the formation of the scale layer;

[0040] Step 4: When the scale layer gradually forms, thickens, and eventually exceeds the gap between the scraper plate (306) and the heat exchange tube (13), the scale layer exceeding the gap distance will be promptly cleaned by the moving scraper plate (306), thereby separating from the heat exchange tube (13) and, under the action of liquid turbulence and gravity, deposited at the bottom of the shell (4), and cleaned and discharged from the dirt outlet (11).

[0041] Effect experiment example 1:

[0042] In the field of coal chemical industry, the problem of fouling and clogging has always restricted the separation of phenol-ammonia wastewater in the treatment of phenol-ammonia wastewater. Affected by the fouling of the heat transfer device, in the traditional phenol-ammonia wastewater distillation and deammonification process, the reboiler is generally set up with two reboilers, and the wastewater is treated by the pipe pass. Every 10-15 days, the reboiler heat exchange tube bundle must be dismantled and cleaned, which not only greatly wastes manpower and material resources, but also sharply deteriorates the heat transfer effect of the reboiler, and also affects the distillation separation operation, resulting in a huge waste of energy.

[0043] After replacing the online descaling reboiler of the present invention, its specific data are shown in the following table:

[0044]

[0045] As shown above, the plugging period of the online descaling reboiler of the present invention is significantly longer than that of the traditional reboiler, and the heat transfer system is still very high after 45 days of operation, far exceeding the traditional reboiler, and saves manpower, material resources and economic costs.

[0046] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0047] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An online descaling device for shell-and-tube heat exchange equipment that resists fouling and clogging, characterized in that: The invention comprises a shell-and-tube heat exchange tube (13), wherein a scraper assembly (3) is arranged outside the heat exchange tube (13), and the scraper assembly (3) comprises a support plate (301) away from one end of the heat exchange tube (13), and a plurality of scraper plates (306) sleeved on the heat exchange tube (13); the plurality of scraper plates (306) are arranged at equal intervals and divided into two layers, which are vertically staggered and arranged; the upper parts of the scraper plates (306) of the upper layer are fixedly connected to the support plate (301) through a tie rod 1 (302) penetrating the upper scraper plates (306); the lower parts of the scraper plates (306) of the lower layer are fixedly connected to the support plate (301) through a tie rod 2 (305) penetrating the lower scraper plates (306); the end of the tie rod 1 (302) away from the support plate (301) is connected to the scraper plate (306) of the upper layer which is farthest from the support plate (301). ) are fixedly connected, one end of the pull rod 2 (305) away from the support plate (301) is fixedly connected to the scraper plate (306) of the lower layer farthest from the support plate (301); the adjacent scrapers (306) of the upper layer are separated by a distance tube 1 (304) sleeved on the pull rod 1 (302); the adjacent scrapers (306) of the lower layer are separated by a distance tube 2 (307) sleeved on the pull rod 2 (305); the lower part of the scraper plate (306) of the upper layer and the upper part of the scraper plate (306) of the lower layer are also connected by a distance rod (303) that runs through all the scrapers (306), and the distance rod (303) is fixedly connected to the support plate (301); the side of the support plate (301) away from the heat exchange tube (13) is connected to the rigid shaft (7); the outer side of the rigid shaft (7) is connected to a reciprocating mechanical unit (9).

2. The online descaling device according to claim 1, characterized in that: The scraper plate (306) has a plate hole, and is sleeved on the heat exchange tube (13) through the plate hole. The matching deviation between the plate hole and the heat exchange tube (13) is that the inner diameter of the plate hole is the outer diameter of the heat exchange tube (13) + 0 to 0.2 mm.

3. The online descaling device according to claim 1, characterized in that: The movement stroke distance of all the scraping plates (306) in the scraping assembly (3) is consistent with the movement stroke provided by the reciprocating motion mechanical unit (9).

4. The online descaling device according to claim 1, characterized in that: The number of the scraping plates (306) is greater than the quotient of the length of the heat exchange tube (13) and the movement stroke distance.

5. A reboiler comprising the online descaling device according to claim 1, characterized in that: The device further comprises a shell (4), wherein a cleaning body inlet (1) is provided on the upper surface of one end of the shell (4), the cleaning body inlet (1) is connected to one end of a heat exchange tube (13) in an online descaling device, and the other end of the heat exchange tube (13) is connected to a cleaning body outlet (15) provided on the lower surface of the shell (4), and the cleaning body runs through the tube during the heat exchange process; a high-contaminant system inlet (2) is also provided on the upper surface of the shell (4), and a contaminant outlet (10) and a dirt outlet (11) are provided on the bottom surface of the shell (4); during the heat exchange process, high-contaminants run through the shell; and a gas phase outlet (5) is also provided on the upper surface of the shell (4).

6. The reboiler according to claim 2, characterized in that: The heat exchange tube (13) is located inside the shell (4), and its inlet and outlet ends are fixedly connected to the shell (4) via a partition (14). The partition (14) divides the reboiler into a tube side part and a shell side part.

7. The reboiler according to claim 3, characterized in that: The bottom of the partition (14) is fixedly connected to the bottom of the support plate (301) via a horizontal guide rail (12); the scraper assembly (3) can reciprocate along the guide rail (12) within the length of the heat exchange tube (13) under the action of the reciprocating mechanical unit (9).

8. The reboiler according to claim 2, characterized in that: The reciprocating mechanical unit (9) is arranged outside the reboiler and connected to the rigid shaft (7) via a shaft pin (8). The rigid shaft (7) is connected to the scraper assembly (3) inside the shell (4). A mechanical sealing device is used at the position where the rigid shaft (7) enters and exits the shell (4) to ensure that the medium in the shell (4) does not leak.

9. The method for online descaling of a reboiler according to claim 2, characterized in that: The steps include: Step 1: The clean material system goes through the tube side, enters the heat exchange tube (13) from the clean body inlet (1), and flows out from the clean body outlet (15) after heat exchange; the high-pollutant material goes through the shell side, enters the shell (4) from the high-pollutant system inlet (2), and flows out of the heat exchanger from the polluted material outlet (10) after heat exchange; Step 2: When the dirt is attached to the outer surface of the heat exchange tube (13) due to the heat, the reciprocating mechanical unit (9) is started, and the scraping component (3) can reciprocate within the length of the heat exchange tube (13) under the action of the reciprocating mechanical unit (9); Step 3: The slow movement of the scraping assembly (3) increases the turbulence of the dirt between two adjacent scraping plates (306), thereby delaying the formation of the scale layer; Step 4: When the scale layer gradually forms, thickens, and eventually exceeds the gap between the scraper plate (306) and the heat exchange tube (13), the scale layer exceeding the gap distance will be promptly cleaned by the moving scraper plate (306), thereby separating from the heat exchange tube (13) and, under the action of liquid turbulence and gravity, deposited at the bottom of the shell (4), and cleaned and discharged from the dirt outlet (11).

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