Heat storage and conduction device for waste heat boiler

Abstract

The utility model discloses a heat storage conduction device for a waste heat boiler, and relates to the technical field of waste heat boilers. According to the technical scheme, the waste heat boiler sequentially comprises a steam pocket, a high-temperature superheater, an upper low-temperature superheater, a lower low-temperature superheater, an evaporation section, a high-temperature coal economizer and a low-temperature coal economizer which are communicated from top to bottom, and fin type heat exchangers are arranged in the upper low-temperature superheater, the lower low-temperature superheater, the evaporation section, the high-temperature coal economizer and the low-temperature coal economizer; the heat storage and conduction device comprises hollow heat storage and conduction pipes, a plurality of holes are formed in the walls of the heat storage and conduction pipes, and a row of heat storage and conduction pipes are installed below the lowest row of heat exchange pipes of the fin heat exchangers in the upper low-temperature superheater, the lower low-temperature superheater, the evaporation section, the high-temperature coal economizer and the low-temperature coal economizer. The device provided by the utility model meets the requirement of reducing the exhaust temperature of the flue gas of the waste heat boiler at the last stage of operation of the catalytic cracking device, achieves the purposes of energy conservation and emission reduction, and simultaneously can reduce the risk caused by load increase of the flue gas desulfurization tower.

Description

Technical Field

[0001] The utility model relates to the technical field of waste heat boilers, in particular to a heat storage and conduction device for waste heat boilers. Background Art

[0002] The catalytic cracking unit of petroleum will use a waste heat boiler to make the high-temperature flue gas flow continuously through the fin heat exchanger in the waste heat boiler. The high-temperature flue gas will exchange heat with the low-temperature process fluid medium in the fin tube bundle, transfer heat, and heat the process fluid medium passing through the fin tube to achieve waste heat recovery. Therefore, the waste heat boiler is mainly used to recover the physical sensible heat of the high-temperature flue gas at the tail of the petroleum catalytic cracking unit, preheat the medium-pressure feed water temperature of the external heat exchanger and the oil slurry steam generator, and re-superheat the medium-pressure steam produced by the waste heat boiler, the medium-pressure steam produced by the external heat exchanger, and the medium-pressure steam produced by the oil slurry steam generator, and finally recover the waste heat to achieve the purpose of reducing the exhaust temperature.

[0003] After the catalytic cracking unit's waste heat boiler had been in operation for three years, the heat exchange fin tube surface was dusty and the shock wave soot blowing effect was poor, resulting in poor flue gas waste heat recovery by the waste heat boiler. The exhaust gas temperature was more than 50°C higher than the flue gas dew point temperature, resulting in waste heat from the flue gas and increased load on the flue gas desulfurization tower. During the start-up process, it was impossible to clean the heat exchange fin tube surface to reduce the exhaust temperature.

[0004] When the high-temperature flue gas passes through the fin heat exchanger, the high-temperature flue gas exchanges heat with the heat exchange tube by heat conduction, and transfers the heat to the heat exchange tube. However, a part of the high-temperature flue gas does not directly contact the heat exchange tube. From a microscopic perspective, the temperature of this part of the high-temperature flue gas is higher than the temperature of the flue gas that is in direct contact with the heat exchange tube. Therefore, the problem of normal waste heat recovery of high-temperature flue gas by the waste heat boiler at the end of the operation of the catalytic cracking unit can be solved from the perspective of increasing the heat exchange of this part of the high-temperature flue gas. Utility Model Content

[0005] The technical problem to be solved by the utility model is: to overcome the shortcomings of the prior art and provide a heat storage and conduction device for a waste heat boiler, so as to meet the requirement of reducing the exhaust temperature of the flue gas from the waste heat boiler at the end of the operation of the catalytic cracking unit, thereby achieving the purpose of energy saving and emission reduction, and at the same time reducing the risk caused by the increase in the load of the flue gas desulfurization tower.

[0006] The technical solution of the utility model is:

[0007] A heat storage conduction device for a waste heat boiler, wherein the waste heat boiler includes, from top to bottom, a connected steam drum, a high-temperature superheater, an upper low-temperature superheater, a lower low-temperature superheater, an evaporator section, a high-temperature economizer and a low-temperature economizer, wherein finned heat exchangers are arranged in the upper low-temperature superheater, the lower low-temperature superheater, the evaporator section, the high-temperature economizer and the low-temperature economizer; the heat storage conduction device includes a hollow heat storage conduction tube, a plurality of holes are arranged on the wall of the heat storage conduction tube, and a row of heat storage conduction tubes is installed below the lowest row of heat exchange tubes of the finned heat exchangers in the upper low-temperature superheater, the lower low-temperature superheater, the evaporator section, the high-temperature economizer and the low-temperature economizer.

[0008] Preferably, the heat storage conduction tubes at various locations are staggered with the corresponding bottom row of heat exchange tubes.

[0009] Preferably, the heat storage conduction tube is located in the middle of two adjacent heat exchange tubes in the bottom row of heat exchange tubes.

[0010] Preferably, the vertical distance between the heat storage conduction tube and the bottom row of heat exchange tubes is 5 cm.

[0011] Preferably, both ends of the heat storage and conduction tube are fixed to the refractory lining material of the waste heat boiler furnace wall by anchoring nails.

[0012] Preferably, the heat storage conduction tube is made of corundum.

[0013] Compared with the prior art, the utility model has the following beneficial effects:

[0014] The utility model adds a row of heat storage conduction tubes below the bottom row of heat exchange tubes in the upper low-temperature superheater, lower low-temperature superheater, evaporation section, high-temperature economizer and low-temperature economizer of the waste heat boiler, mainly to absorb the heat of the high-temperature flue gas that is not directly in contact with the heat exchange tubes, and conduct this part of the heat to the corresponding heat exchange tubes by thermal radiation, so that it heats the medium in the heat exchange tubes again, achieving the purpose of waste heat recovery. The device of this embodiment meets the requirement of reducing the exhaust temperature of the flue gas of the waste heat boiler at the end of the operation of the catalytic cracking unit, achieving the purpose of energy saving and emission reduction, and at the same time can reduce the risk caused by the increase in the load of the flue gas desulfurization tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of a heat storage and conduction device for a waste heat boiler of the utility model.

[0016] Figure 2 It is a structural diagram of a waste heat boiler.

[0017] Figure 3 It is a top view of the heat storage and conduction device for a waste heat boiler of the utility model in the waste heat boiler.

[0018] In the figure, 1, steam drum; 2, high-temperature superheater; 3, upper low-temperature superheater; 4, lower low-temperature superheater; 5, evaporation section; 6, high-temperature economizer; 7, low-temperature economizer; 8, heat exchange tube; 9, heat storage conduction tube; 901, hole. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0020] Example 1

[0021] This embodiment provides a heat storage and conduction device for a waste heat boiler, such as Figure 2 As shown, the waste heat boiler is an existing I-type upper and lower structure waste heat boiler, which includes, from top to bottom, a connected steam drum 1, a high-temperature superheater 2, an upper low-temperature superheater 3, a lower low-temperature superheater 4, an evaporator section 5, a high-temperature economizer 6 and a low-temperature economizer 7. Fin heat exchangers are arranged in the upper low-temperature superheater 3, the lower low-temperature superheater 4, the evaporator section 5, the high-temperature economizer 6 and the low-temperature economizer 7. Other specific structures are not repeated here.

[0022] like Figure 1 As shown, in this embodiment, the heat storage conduction device includes a hollow heat storage conduction tube 9, and a plurality of holes 901 for smoke to pass through are arranged on the wall of the heat storage conduction tube 9, such as Figure 3 As shown, a row of heat storage and conduction tubes 9 is installed below the bottom row of heat exchange tubes 8 of the fin heat exchangers in the upper low-temperature superheater 3, the lower low-temperature superheater 4, the evaporation section 5, the high-temperature economizer 6 and the low-temperature economizer 7. The diameter of the heat storage and conduction tubes 9 is the same as that of the heat exchange tubes 8 and is made of corundum.

[0023] In this embodiment, holes 901 are distributed on the wall of the heat storage and conduction tube 9. This honeycomb cavity structure has a large surface area and a large contact area with the high-temperature flue gas, which can quickly absorb heat and generate heat radiation without increasing the pressure drop of the waste heat boiler. A circular hole 901 for installing an anchor nail is left at each end of the heat storage and conduction tube 9, and the heat storage and conduction tube 9 is fixed to the refractory lining material of the furnace wall at various locations of the waste heat boiler through the anchor nail.

[0024] The heat storage conduction tube 9 can produce a black body effect. Under the same heat radiation environment, the heat storage conduction tube 9 with a honeycomb cavity structure can produce a stronger radiation intensity to the heat exchange tube 8 of the waste heat boiler. In addition, in order to make full use of the heat of the high-temperature flue gas in each device of the waste heat boiler that is not directly in contact with the heat exchange tube 8, the heat storage conduction tube 9 at each device can be staggered with the corresponding bottom row of heat exchange tubes 8, that is, each heat storage conduction tube 9 is in the middle of two heat exchange tubes 8, so that the high-temperature flue gas that is not directly in contact with the heat exchange tube 8 can be vertically passed through each heat storage conduction tube 9, and the heat storage conduction tube 9 is heat-conducted and heat-stored. The heat storage conduction tube 9 then radiates its stored heat to the upper heat exchange tube 8, so that it heats the medium in the heat exchange tube 8 again, and the purpose of waste heat recovery is achieved. The vertical distance between the heat storage conduction tube 9 and the bottom row of heat exchange tubes 8 is 5 cm, which can ensure that the heat storage conduction tube 9 is fully stored. The heat storage conduction pipe 9 of this embodiment can disturb the flow of flue gas in the furnace, so that the high-temperature flue gas can fully transfer heat; it can prevent the pressure drop of the waste heat boiler from increasing; it can reduce the exhaust temperature of the flue gas; it can reduce the load of the flue gas desulfurization tower, and ensure the safe and stable production operation of the device.

Claims

1. A heat storage conduction device for a waste heat boiler, wherein the waste heat boiler comprises, from top to bottom, a steam drum (1), a high-temperature superheater (2), an upper low-temperature superheater (3), a lower low-temperature superheater (4), an evaporator section (5), a high-temperature economizer (6) and a low-temperature economizer (7) which are connected to each other, and a fin heat exchanger is arranged in the upper low-temperature superheater (3), the lower low-temperature superheater (4), the evaporator section (5), the high-temperature economizer (6) and the low-temperature economizer (7); characterized in that: The heat storage conduction device comprises a hollow heat storage conduction tube (9), a plurality of holes (901) are arranged on the wall of the heat storage conduction tube (9), and a row of heat storage conduction tubes (9) are installed below the bottom row of heat exchange tubes (8) of the fin heat exchangers in the upper low-temperature superheater (3), the lower low-temperature superheater (4), the evaporation section (5), the high-temperature economizer (6) and the low-temperature economizer (7).

2. The heat storage conduction device for waste heat boiler according to claim 1, characterized in that: The heat storage conduction tubes (9) at various locations are arranged in a staggered manner with respect to the corresponding bottom row of heat exchange tubes (8).

3. The heat storage conduction device for waste heat boiler according to claim 2, characterized in that: The heat storage conduction tube (9) is located in the middle of two adjacent heat exchange tubes (8) in the bottom row of heat exchange tubes (8).

4. The heat storage conduction device for waste heat boiler according to claim 1, characterized in that: The vertical distance between the heat storage conduction tube (9) and the bottom row of heat exchange tubes (8) is 5 cm.

5. The heat storage conduction device for waste heat boiler according to claim 1, characterized in that: Both ends of the heat storage and conduction pipe (9) are fixed to the refractory lining material of the waste heat boiler furnace wall by anchoring nails.

6. The heat storage conduction device for a waste heat boiler according to claim 1, characterized in that: The heat storage conduction tube (9) is made of corundum.

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