Waste heat recovery system for catalytic cracking reaction product

Abstract

The utility model relates to the technical field of preheating recoverers, in particular to a catalytic cracking reaction product waste heat recovery system and method. The recovery system comprises a waste heat recoverer and a steam separator, the waste heat recoverer comprises a shell, and a heat exchange pipe is arranged in the shell; a partition plate is arranged in the shell in the radial direction and divides the shell into a first small shell and a second small shell. The volume of the first small shell is smaller than that of the second small shell, the first small shell and the second small shell are both connected with the steam separator through a cooling water inlet pipe and a cooling water return pipe, and the cooling water inlet pipe is connected with a water inlet pump; heat is recycled twice, steam is conveyed through the two pipelines, the steam can be quickly released after absorbing the heat, and the quick release of the heat has the advantage of reducing the damage of high temperature to equipment; and a part of heat is absorbed in the small shell I, so that the axial stress and the pulling-out force borne by equipment in the small shell II are reduced, and the service life is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of preheat recovery devices, in particular to a waste heat recovery system for catalytic cracking reaction products. Background Art

[0002] The catalytic cracking reaction process is a common process in chemical production. A large amount of heat is generated during the material reaction process, causing the temperature of the material after the reaction to reach 500°C, which basically reaches the upper limit of the use temperature of common materials for pressure vessels. High temperature will lead to a series of hazards such as reduced equipment carrying capacity, thermal fatigue, high-temperature creep and material degradation. Therefore, the reaction materials need to be quickly cooled before entering the post-processing process; at the same time, in order to reduce the heat loss of the system and improve the efficiency of energy recovery and utilization, the heat carried by the reaction materials must also be recovered and reused; the traditional process system uses chemical heat exchange equipment to recover heat. Since the temperature of the material after the reaction is too high, the metal temperature difference between the processes is large after the reaction materials enter the heat exchange equipment, and the heat cannot be dissipated quickly. The axial stress of the shell, the axial stress of the heat exchange tube, and the pull-off force between the tube sheet and the heat exchange tube cannot meet the requirements, which can easily cause equipment failure and affect equipment and personal safety. Utility Model Content

[0003] The main purpose of the utility model is to provide a waste heat recovery system for catalytic cracking reaction products, so as to solve the problem in the above-mentioned prior art that the metal temperature difference between processes is large after the heat exchange equipment, and the heat cannot be dissipated quickly, which easily causes equipment failure and affects equipment and personal safety.

[0004] In order to achieve the above-mentioned purpose, the utility model provides a waste heat recovery system for catalytic cracking reaction products, including a waste heat recovery device and a steam separator. The waste heat recovery device includes a shell, and a heat exchange pipe is arranged inside the shell; a partition plate is arranged inside the shell along the radial direction, and the partition plate divides the shell into a small shell one and a small shell two; the volume of the small shell one is smaller than the volume of the small shell two, and the small shell one and the small shell two are connected to the steam separator through a cooling water inlet pipe and a cooling water return pipe, and the cooling water inlet pipe is connected to an inlet pump.

[0005] Furthermore, the volume of the small shell 2 is 5.5 to 6 times the volume of the small shell 1.

[0006] Furthermore, one end of the shell is fixedly connected to the front tube plate and the front tube box; the other end of the shell is fixedly connected to the rear tube plate and the rear tube box; the front tube plate and the front tube box are both connected to the shell through a flexible transition arc; the front tube box is connected to the cracking product inlet pipe and the cracking product outlet pipe.

[0007] Furthermore, a fire-resistant insulation layer is fixedly connected to the side of the front tube plate toward the front tube box, the fire-resistant insulation layer is U-shaped, and the fire-resistant insulation layer wraps the front side of the front tube plate and the connection between the front tube plate and the shell; a protective plate is fixedly connected to the side of the fire-resistant insulation layer toward the front tube box, and the protective plate is fixedly connected to the front tube plate by fastening screws; an anchor nail is fixedly connected to the front tube plate, and the anchor nail is located in the fire-resistant insulation layer.

[0008] Furthermore, the heat exchange tube passes through the front tube plate and the rear tube plate, and a high-temperature resistant casing is provided inside the heat exchange tube. The front part of the casing passes through the fire-resistant insulation layer and the protective plate, and is fixedly connected to the heat exchange tube near the front tube plate; a ceramic fiber insulation layer is fixedly connected between the casing and the heat exchange tube.

[0009] Furthermore, the steam separator is connected to a water inlet pipe and a steam exhaust pipe, and the steam exhaust pipe is connected to a thermal network.

[0010] Furthermore, the material of the portion of the heat exchange tube located in the small shell one is high temperature resistant stainless steel; the material of the portion of the heat exchange tube located in the small shell two is Cr-Mo steel.

[0011] The beneficial effects of the utility model are:

[0012] By dividing the shell into small shell one and small shell two, heat is recovered twice, and steam is transported through two pipes. After absorbing heat, the steam can release it quickly. The advantage of quick heat release is that it reduces the damage to the equipment caused by high temperature. Moreover, after absorbing part of the heat in small shell one, when the catalytic cracking reaction product flows through small shell two, the temperature is not very high, so that the axial stress and pull-off force on the equipment in small shell two will be reduced, so that the material requirements for the equipment in small shell two are not so harsh, the material cost can be reduced, and the service life is increased.

[0013] The connection between the heat exchange tube and the front tube plate is most susceptible to damage due to high temperature impact; by setting the sleeve, part of the heat transfer can be blocked here to protect this place from high temperature damage.

[0014] By providing a fire-resistant insulation layer and a protective plate, the front tube plate can be protected and prevented from being damaged by the impact of high-temperature catalytic cracking reaction products.

[0015] By setting a flexible transition arc, stress concentration can be alleviated and the service life can be extended. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings in the specification, which constitute a part of the present application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0017] Figure 1It is a structural schematic diagram of an embodiment;

[0018] Figure 2 Schematic diagram of the structure of the front tube plate in the embodiment;

[0019] Figure 3 for Figure 2 Schematic diagram of the structure at position Ⅰ.

[0020] In the figure: 1. Waste heat recovery device; 101. Rear tube sheet; 102. Front tube sheet; 103. Heat exchange tube; 104. Partition plate; 105. Small shell one; 106. Small shell two; 2. Steam separator; 201. Water inlet pipe; 202. Steam outlet pipe; 3. Cooling water inlet pipe; 4. Cooling water return pipe; 5. Water inlet pump; 6. Front tube box; 7. Rear tube box; 8. Cracking product inlet pipe; 9. Cracking product outlet pipe; 10. Refractory insulation layer; 11. Protective plate; 12. Fastening screws; 13. Anchor nails; 14. Casing; 15. Transition arc. DETAILED DESCRIPTION

[0021] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present utility model will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0022] like Figures 1 to 3 As shown, according to an embodiment of the utility model, a catalytic cracking reaction product waste heat recovery system is provided, including a waste heat recovery device 1 and a steam separator 2, the waste heat recovery device 1 includes a shell, and a heat exchange tube 103 is arranged inside the shell; a partition plate 104 is arranged inside the shell along the radial direction, and the partition plate 104 divides the shell into a small shell 1 105 and a small shell 2 106; the volume of the small shell 1 105 is smaller than the volume of the small shell 2 106, and the small shell 1 105 and the small shell 2 106 are both connected to the steam separator 2 through a cooling water inlet pipe 3 and a cooling water return pipe 4, and the cooling water inlet pipe 3 is connected to an inlet pump 5.

[0023] The volume of the small shell 2 106 is 5.5 to 6 times the volume of the small shell 1 105 .

[0024] One end of the shell is fixedly connected with the front tube sheet 102 and the front tube box 6; the other end of the shell is fixedly connected with the rear tube sheet 101 and the rear tube box 7; the front tube sheet 102 and the front tube box 6 are connected to the shell through a flexible transition arc 15; the flexible transition arc 15 can alleviate stress concentration and extend the service life; the front tube box 6 is connected with a cracking product inlet pipe 8 and a cracking product outlet pipe 9.

[0025] like Figure 2As shown, a refractory insulation layer 10 is fixedly connected to the side of the front tube plate 102 facing the front tube box 6. The material of the refractory insulation layer 10 is special refractory cement. The refractory insulation layer 10 is U-shaped. The refractory insulation layer 10 wraps the front side of the front tube plate 102 and the connection between the front tube plate 102 and the shell; a protective plate 11 is fixedly connected to the side of the refractory insulation layer 10 facing the front tube box 6. The protective plate 11 is fixedly connected to the front tube plate 102 by fastening screws 12, and the fastening screws 12 are welded to the front tube plate 102; anchor nails 13 are welded to the front tube plate 102, and the anchor nails 13 are located in the refractory insulation layer 10; by arranging the refractory insulation layer 10 and the protective plate 11, the front tube plate 102 can be protected to prevent the front tube plate 102 from being damaged by the impact of high-temperature catalytic cracking reaction products.

[0026] like Figure 3 As shown, the heat exchange tube 103 passes through the front tube plate 102 and the rear tube plate 101, and a high-temperature resistant sleeve 14 is arranged in the heat exchange tube 103. The sleeve 14 is made of high-temperature resistant stainless steel. The front part of the sleeve 14 passes through the fire-resistant insulation layer 10 and the protective plate 11, and the rear part is fixedly connected to the heat exchange tube 103 near the front tube plate 102; the length of the sleeve 14 extending into the heat exchange tube 103 is not less than 250 mm; a ceramic fiber insulation layer is fixedly connected between the sleeve 14 and the heat exchange tube 103; the connection between the heat exchange tube 103 and the front tube plate 102 is most susceptible to damage due to high temperature impact; by arranging the sleeve 14, part of the heat transmission can be blocked here to protect this place from high temperature damage.

[0027] The steam separator 2 is connected to a water inlet pipe 201 and a steam exhaust pipe 202 , and the steam exhaust pipe 202 is connected to a thermal network.

[0028] The material of the portion of the heat exchange tube 103 located in the small shell 1 105 is high temperature resistant stainless steel; the material of the portion located in the small shell 2 106 is Cr-Mo steel.

[0029] According to an embodiment of the present invention, a method for recovering waste heat from a catalytic cracking reaction product is also provided. Using the above-mentioned waste heat recovery system for a catalytic cracking reaction product, the steps are as follows:

[0030] S1, introducing cooling water into the steam separator 2;

[0031] S2, passing the cooling water in the steam separator 2 into the small shell 1 105 and the small shell 2 106;

[0032] S3, the catalytic cracking reaction product is passed into the front pipe box 6, and the temperature of the catalytic cracking reaction product is 456°C~520°C; then the catalytic cracking reaction product enters the heat exchange tube 103, and then exchanges heat with the cooling water in the small shell 1 105 and the small shell 2 106 in turn, and is finally discharged through the rear pipe box 7; wherein the temperature is reduced to 300°C~350°C after heat exchange in the small shell 105, and the temperature is reduced to 270°C~300°C after heat exchange in the small shell 2 106; the cooling water in the small shell 105 and the small shell 2 106 absorbs heat to form a water vapor mixture, and the water vapor mixture enters the steam separator 2;

[0033] S4. The water-vapor mixture is separated in the steam separator 2, and the separated steam enters the thermal network for recycling. The separated water is mixed with the cooling water added to the steam separator 2 and then enters the small shell 1 105 and the small shell 2 106 for recycling.

[0034] In this embodiment, the shell is divided into a small shell 105 and a small shell 2 106. Heat is recovered twice and steam is transported through two pipes. The steam can release heat quickly after absorbing it. The advantage of rapid heat release is that it reduces the damage to the equipment caused by high temperature. Moreover, after absorbing part of the heat in the small shell 105, when the catalytic cracking reaction products flow through the small shell 2 106, the temperature is not very high, so that the axial stress and pull-off force on the equipment in the small shell 2 106 will be reduced, so that the material requirements for the equipment in the small shell 2 106 are not so harsh, the material cost can be reduced, and the service life is increased.

[0035] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A waste heat recovery system for catalytic cracking reaction products, comprising a waste heat recovery device (1) and a steam separator (2), wherein the waste heat recovery device (1) comprises a shell, and a heat exchange tube (103) is arranged inside the shell; characterized in that: A partition plate (104) is provided inside the shell along a radial direction, and the partition plate (104) divides the shell into a small shell one (105) and a small shell two (106); the volume of the small shell one (105) is smaller than the volume of the small shell two (106), and both the small shell one (105) and the small shell two (106) are connected to the steam separator (2) via a cooling water inlet pipe (3) and a cooling water return pipe (4), and the cooling water inlet pipe (3) is connected to a water inlet pump (5).

2. The catalytic cracking reaction product waste heat recovery system according to claim 1, characterized in that: The volume of the small shell 2 (106) is 5.5 to 6 times the volume of the small shell 1 (105).

3. The catalytic cracking reaction product waste heat recovery system according to claim 1, characterized in that: One end of the shell is fixedly connected to a front tube sheet (102) and a front tube box (6); the other end of the shell is fixedly connected to a rear tube sheet (101) and a rear tube box (7); the front tube sheet (102) and the front tube box (6) are both connected to the shell via a flexible transition arc (15); the front tube box (6) is connected to a cracking product inlet pipe (8) and a cracking product outlet pipe (9).

4. The catalytic cracking reaction product waste heat recovery system according to claim 3, characterized in that: A fire-resistant thermal insulation layer (10) is fixedly connected to the side of the front tube plate (102) facing the front tube box (6); the fire-resistant thermal insulation layer (10) is U-shaped, and the fire-resistant thermal insulation layer (10) wraps the front side of the front tube plate (102) and the connection between the front tube plate (102) and the shell; a protective plate (11) is fixedly connected to the side of the fire-resistant thermal insulation layer (10) facing the front tube box (6); the protective plate (11) and the front tube plate (102) are fixedly connected by fastening screws (12); and an anchoring nail (13) is fixedly connected to the front tube plate (102); the anchoring nail (13) is located in the fire-resistant thermal insulation layer (10).

5. The catalytic cracking reaction product waste heat recovery system according to claim 3, characterized in that: The heat exchange tube (103) passes through the front tube plate (102) and the rear tube plate (101); a high temperature resistant sleeve (14) is provided inside the heat exchange tube (103); the front portion of the sleeve (14) passes through the fireproof insulation layer (10) and the protective plate (11); the rear portion is fixedly connected to a position on the heat exchange tube (103) close to the front tube plate (102); and a ceramic fiber insulation layer is fixedly connected between the sleeve (14) and the heat exchange tube (103).

6. The catalytic cracking reaction product waste heat recovery system according to claim 1, characterized in that: The steam separator (2) is connected to a water inlet pipe (201) and a steam exhaust pipe (202), and the steam exhaust pipe (202) is connected to a thermal network.

7. The catalytic cracking reaction product waste heat recovery system according to claim 1, characterized in that: The material of the portion of the heat exchange tube (103) located in the small shell one (105) is high temperature resistant stainless steel; the material of the portion located in the small shell two (106) is Cr-Mo steel.

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