Adjustable temperature hot blast stove

Abstract

The utility model relates to air indirect heating technical field especially, especially adjustable exhaust temperature hot blast furnace, including hot blast furnace frame, the inside of hot blast furnace frame is fixed with high temperature section plate heat exchanger and low temperature section plate heat exchanger, and high temperature section plate heat exchanger's air passage and low temperature section plate heat exchanger's air passage intercommunication, the flue gas passage of high temperature section plate heat exchanger and low temperature section plate heat exchanger is connected through adjustable lift valve and is connected through adjustable lift valve, when exhaust temperature is close to dew point temperature 60 DEG C in winter, rotates valve stem and drives valve plate to descend slowly, blocks low temperature section plate heat exchanger partial flue gas passage, reduces heat exchange area to exhaust temperature and rises, avoids condensate to corrode hot blast furnace low temperature section plate heat exchanger and exhaust fan and precipitate.

Description

Technical Field

[0001] This utility model relates to the field of indirect air heating technology, and in particular to an adjustable flue gas temperature hot air furnace. Background Technology

[0002] The principle of an indirect heat exchange hot air furnace: Natural gas is fully combusted in the combustion chamber to produce high-temperature hot flue gas at a temperature of 1300-1500℃. The heat is rapidly transferred to the low-temperature fresh air mainly through thermal radiation. The flue gas temperature drops to below 750℃ and enters the heat exchanger. Then, the heat is transferred to the fresh air mainly through convection.

[0003] Among them, the heat exchangers include a high-efficiency corrugated plate heat exchanger with publication number CN219328348U and a plate heat exchanger with publication number CN210570138U. The flue gas passage and the air passage are perpendicular to each other and the inlet and outlet are located on adjacent sides. At the same time, the flue gas passage is a horizontal slit arranged vertically.

[0004] The flue gas temperature of hot blast stoves is greatly affected by the seasons. In summer, the air inlet temperature is high, and the flue gas temperature is also high, ≥100℃. At this temperature, it deviates from the natural gas dew point temperature (around 60℃), so the flue gas will not condense and has less corrosiveness to the equipment. However, in winter, the air inlet temperature is low, especially in northern regions where the temperature drops below 0℃. When the flue gas temperature of the hot blast stove drops to around 70℃, the flue gas condenses due to the cold wall effect, causing corrosion to the heat exchanger and exhaust fan of the hot blast stove. Utility Model Content

[0005] The purpose of this invention is to address the shortcomings of existing technologies, such as low temperatures causing condensation and corrosion of the hot air furnace heat exchanger, and to propose an adjustable flue gas temperature hot air furnace.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] Design an adjustable flue gas temperature hot air furnace, including a hot air furnace frame, wherein a high-temperature section plate heat exchanger and a low-temperature section plate heat exchanger are fixedly installed inside the hot air furnace frame, and the air passage of the high-temperature section plate heat exchanger and the air passage of the low-temperature section plate heat exchanger are connected.

[0008] The flue gas passages of the high-temperature plate heat exchanger and the low-temperature plate heat exchanger are connected by an adjustable lift valve.

[0009] The heating component of the high-temperature plate heat exchanger is used to inject and discharge hot flue gas and hot air into and from the high-temperature plate heat exchanger, respectively.

[0010] Furthermore, the heating assembly includes an outer cylinder fixed within the hot air furnace frame, and a combustion chamber is fixed inside the outer cylinder. A burner interface is installed at one end of the combustion chamber. The combustion chamber and the left end of the outer cylinder are respectively connected to the flue gas passage and air passage of the high-temperature plate heat exchanger. The front end of the hot air furnace frame is provided with a cold end outlet, and the rear end of the cold end outlet is connected to the outer cylinder.

[0011] Furthermore, the flue gas passages of both the low-temperature plate heat exchanger and the high-temperature plate heat exchanger are horizontal slits arranged vertically. The right end face of the valve plate of the adjustable lifting valve is slidably connected to the flue gas passage of the low-temperature plate heat exchanger, and the descending valve plate blocks several flue gas passages sequentially from top to bottom.

[0012] Furthermore, the gaps between the hot air furnace frame and the outer cylinder, the high-temperature plate heat exchanger and the low-temperature plate heat exchanger are filled with an insulation layer.

[0013] Furthermore, the left end of the combustion chamber is connected to the flue gas passage of the high-temperature plate heat exchanger through a bend duct, and both the bend duct and the middle of the combustion chamber are equipped with expansion corrugated cylinders.

[0014] Furthermore, the flue gas passage and air passage of the low-temperature plate heat exchanger are respectively provided with a flue gas outlet and a cold side inlet, and the bottom and top of the cold side inlet are respectively provided with a condensate outlet and a flue gas temperature monitoring port, and a high-temperature thermocouple is installed in the flue gas temperature monitoring port.

[0015] Furthermore, the adjustable lift valve has a valve stem with a structure to block high-temperature transmission, the valve plate is made of cast heat-resistant stainless steel, and the valve frame of the adjustable lift valve is provided with a frame to prevent high-temperature deformation.

[0016] Furthermore, the outer wall of the combustion chamber is fitted with a baffle plate located in the middle of the outer cylinder, and the outer wall of the baffle plate is fixedly connected to the outer cylinder. The rear end of the baffle plate is provided with a notch for air circulation.

[0017] Furthermore, the top of the outer cylinder is provided with a furnace temperature monitoring port located on the left side of the high-temperature plate heat exchanger, and a high-temperature thermocouple is installed inside the furnace temperature monitoring port.

[0018] The adjustable flue gas temperature hot air furnace proposed in this utility model has the following advantages:

[0019] (1) By setting an adjustable lifting valve, when the flue gas temperature is close to the dew point temperature of 60°C in winter, the valve stem is rotated to drive the valve plate to slowly descend, blocking part of the flue gas passage of the low-temperature plate heat exchanger, reducing the heat exchange area and thus increasing the flue gas temperature, avoiding the precipitation of condensate that corrodes the low-temperature plate heat exchanger and the flue gas fan of the hot air furnace.

[0020] (2) By setting an expansion corrugated cylinder, the heat transfer area is increased and the radiation heat transfer intensity is high. At the same time, the thermal expansion problem of the hot air furnace from cold to hot and from hot to cold is fully absorbed, and the cracking of the combustion chamber weld is avoided.

[0021] (3) By setting up an interlayer and baffle between the combustion chamber and the outer cylinder, the air is fully heated by the principle that the main heat transfer mode of flue gas above 750℃ is radiation, thereby increasing the heat transfer area and improving the heat exchange efficiency of the furnace; the cold air goes to the outermost side, saving energy and reducing the consumption of insulation cotton, thus improving the insulation effect.

[0022] (4) By installing high-temperature thermocouples before the high-temperature plate heat exchanger and after the low-temperature plate heat exchanger, the flue gas temperature is monitored, thereby controlling the burner to heat up slowly and avoiding the high-temperature plate heat exchanger from overheating and burning out.

[0023] (5) The valve stem is prevented from being burned by setting a high-temperature transmission blocking structure, and the valve frame is prevented from being deformed by setting a high-temperature deformation prevention frame structure.

[0024] (6) By setting up an insulation layer, the outer wall temperature of the hot air furnace frame is kept below 50°C, which prevents high-temperature burns, reduces heat loss of the hot air furnace, and improves the thermal efficiency of the hot air furnace. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of this utility model;

[0026] Figure 2 This is a schematic diagram of the adjustable lifting valve structure of this utility model;

[0027] Figure 3 This is a schematic diagram of the outer cylinder structure of this utility model;

[0028] Figure 4 This is a schematic diagram of the air baffle structure of this utility model.

[0029] In the diagram: 1. Hot blast stove frame; 2. High-temperature section plate heat exchanger; 21. Furnace temperature monitoring port; 3. Low-temperature section plate heat exchanger; 31. Flue gas outlet; 32. Cold side inlet; 33. Condensate outlet; 34. Flue gas temperature monitoring port; 4. Adjustable lift valve; 41. Valve plate; 42. Valve stem; 43. High-temperature transmission blocking structure; 44. Valve frame; 45. High-temperature deformation resistant frame; 5. Heating assembly; 51. Outer cylinder; 52. Combustion chamber; 53. Burner interface; 54. Cold end outlet; 55. Bend air duct; 56. Expansion corrugated cylinder; 57. Baffle plate; 6. Insulation layer. Detailed Implementation

[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0031] Reference Figures 1-4 As an embodiment of this utility model, it discloses an adjustable flue gas temperature hot air furnace, including a hot air furnace frame 1. A high-temperature plate heat exchanger 2 and a low-temperature plate heat exchanger 3 are fixed inside the hot air furnace frame 1, and the air passage of the high-temperature plate heat exchanger 2 and the air passage of the low-temperature plate heat exchanger 3 are connected.

[0032] The flue gas passages of the high-temperature plate heat exchanger 2 and the low-temperature plate heat exchanger 3 are connected by an adjustable lift valve 4.

[0033] By closing part of the flue gas passage of the low-temperature section plate heat exchanger 3 through the adjustable lift valve 4, the flue gas does not participate in heat exchange. This reduces the number of effective flue gas passages, reduces the effective heat exchange area, and lowers the temperature of the flue gas, resulting in an increase in the temperature of the discharged flue gas and no condensate precipitation.

[0034] The heating component 5 of the high-temperature plate heat exchanger 2 is used to inject and discharge hot flue gas and hot air into the high-temperature plate heat exchanger 2, respectively.

[0035] The high-temperature flue gas generated in the heating component 5 heats the air flowing out of the air passage of the high-temperature plate heat exchanger 2 through heat exchange and heating, and then enters the flue gas passage of the high-temperature plate heat exchanger 2.

[0036] Specifically, the heating assembly 5 includes an outer cylinder 51 fixed inside the hot air furnace frame 1, and a combustion chamber 52 is fixed inside the outer cylinder 51. A burner interface 53 is installed at one end of the combustion chamber 52. The left ends of the combustion chamber 52 and the outer cylinder 51 are respectively connected to the flue gas passage and the air passage of the high-temperature plate heat exchanger 2. The front end of the hot air furnace frame 1 is provided with a cold end outlet 54, and the rear end of the cold end outlet 54 is connected to the outer cylinder 51.

[0037] Natural gas is injected into combustion chamber 52 through burner interface 53 for combustion and flame formation to generate high-temperature flue gas. Cold air flowing out of the air passage of high-temperature plate heat exchanger 2 enters the interlayer between outer cylinder 51 and combustion chamber 52 and flows to the right, exchanging heat with the high-temperature flue gas flowing to the left in combustion chamber 52. The cold air absorbs heat from the high-temperature flue gas and heats up to form hot air, which is discharged through cold end outlet 54. The flue gas flows to the left and is cooled to about 750°C after heat exchange, entering the flue gas passage of high-temperature plate heat exchanger 2.

[0038] It should be noted that the flue gas passages of both the low-temperature plate heat exchanger 3 and the high-temperature plate heat exchanger 2 are horizontal slits arranged vertically. The right end face of the valve plate 41 of the adjustable lift valve 4 is slidably connected to the flue gas passage of the low-temperature plate heat exchanger 3, and the descending valve plate 41 blocks several flue gas passages sequentially from top to bottom. This ensures that the flue gas flowing through the high-temperature plate heat exchanger 2 through the adjustable lift valve 4 can only enter the flue gas passage of the low-temperature plate heat exchanger 3 below the valve plate 41, thereby adjusting the number of effective flue gas passages, changing the effective heat exchange area, and adjusting the temperature drop of the flue gas.

[0039] In order to reduce heat loss from the outer cylinder 51, the high-temperature plate heat exchanger 2 and the low-temperature plate heat exchanger 3, and to transfer heat to the hot air furnace frame 1 and raise its temperature, the gap between the hot air furnace frame 1 and the outer cylinder 51, the high-temperature plate heat exchanger 2 and the low-temperature plate heat exchanger 3 is filled with an insulation layer 6.

[0040] In order to absorb the thermal expansion of the combustion chamber 52 from cold to hot and from hot to cold through the expansion and deformation of the expansion corrugated cylinder 56, and to avoid cracking of the weld of the combustion chamber 52, the left end of the combustion chamber 52 is connected to the flue gas passage of the high-temperature plate heat exchanger 2 through the bend duct 55. The bend duct 55 and the middle of the combustion chamber 52 are both provided with expansion corrugated cylinders 56. The flue gas in the combustion chamber 52 enters the flue gas passage of the high-temperature plate heat exchanger 2 through the bend duct 55.

[0041] In detail, the flue gas passage and air passage of the low-temperature plate heat exchanger 3 are respectively provided with a flue gas outlet 31 and a cold side inlet 32, and the bottom and top of the cold side inlet 32 ​​are respectively provided with a condensate outlet 33 and a flue gas temperature monitoring port 34, and a high-temperature thermocouple is installed in the flue gas temperature monitoring port 34.

[0042] Cold air enters the air passage of the low-temperature plate heat exchanger 3 through the cold side inlet 32. The flue gas flowing through the flue gas passage transfers heat to the cold air flowing through the air passage through the heat exchange plates of the low-temperature plate heat exchanger 3 and is then discharged through the flue gas outlet 31. The condensate generated by the condensation of the flue gas is discharged through the condensate outlet 33. The temperature of the discharged flue gas is detected by a high-temperature thermocouple so as to control the rise and fall of the valve plate 41 according to the temperature.

[0043] To prevent the valve stem 42 of the adjustable lift valve 4 from being burned by the heat generated by contact with flue gas, and to prevent the valve frame 44 and valve plate 41 from deforming due to high temperature, the valve stem 42 of the adjustable lift valve 4 is provided with a high temperature transmission blocking structure 43, the valve plate 41 is made of cast heat-resistant stainless steel, and the valve frame 44 of the adjustable lift valve 4 is provided with a high temperature deformation prevention frame 45.

[0044] To increase airflow, a baffle plate 57 located in the middle of the outer cylinder 51 is fitted on the outer wall of the combustion chamber 52, and the outer wall of the baffle plate 57 is fixedly connected to the outer cylinder 51. The rear end of the baffle plate 57 has a notch for airflow, so that when air flows from left to right in the interlayer between the outer cylinder 51 and the combustion chamber 52, the air first flows backward to the notch and then flows through the notch to the right side of the baffle plate 57 and the rear side of the combustion chamber 52, and then splits into two airflows that flow from the upper and lower sides of the combustion chamber 52 to the cold end outlet 54. The air first flows backward and then forward through two processes and splits into two airflows that flow forward through the upper and lower surfaces of the combustion chamber 52, resulting in a longer flow path and more thorough contact with the combustion chamber 52.

[0045] In order to monitor the temperature of the flue gas entering the high-temperature plate heat exchanger 2, and adjust the amount of natural gas injected into the combustion chamber 52 according to the flue gas temperature, thereby controlling the flue gas temperature gradient to rise slowly and avoiding the high-temperature plate heat exchanger from overheating and burning out, a furnace temperature monitoring port 21 is opened at the left end of the high-temperature plate heat exchanger 2, and a high-temperature thermocouple is installed in the furnace temperature monitoring port 21.

[0046] Working method: Cold air enters the air passage of the low-temperature plate heat exchanger 3 through the cold end inlet, then enters the air passage of the high-temperature plate heat exchanger 2, and then enters the interlayer between the outer cylinder 51 and the combustion chamber 52 before being discharged to the right through the cold end outlet 54.

[0047] The natural gas injected into the combustion chamber 52 through the burner interface 53 generates high-temperature flue gas that flows to the left and is injected into the flue gas passage of the high-temperature plate heat exchanger 2 through the bend duct 55. The air then enters the flue gas passage of the low-temperature plate heat exchanger 3 through the adjustable lift valve 4 and is finally discharged through the exhaust port 31.

[0048] The flue gas and cold air exchange heat as they flow through the combustion chamber 52 and the interlayer, respectively. The flue gas initially transfers heat to the cold air, causing it to heat up three times and then decrease to 750°C. The flue gas and cold air exchange heat with the air passage as they flow through the flue gas passage of the high-temperature plate heat exchanger 2, respectively. The flue gas then transfers heat to the cold air a second time, causing it to heat up a second time. The flue gas and cold air exchange heat with the air passage as they flow through the flue gas passage of the low-temperature plate heat exchanger 3, respectively. The flue gas then transfers heat to the cold air a third time, causing it to heat up a first time.

[0049] When the flue gas temperature is close to the dew point temperature of 60°C in winter, a small amount of condensate can be discharged from the condensate outlet 33. By rotating the handle at the top of the valve stem 42, the valve plate 41 is lowered, thereby blocking several flue gas passages of the low-temperature plate heat exchanger 3 from top to bottom through the lowered valve plate 41, preventing them from participating in heat exchange. This reduces the number of effective flue gas passages, reduces the effective heat exchange area, and lowers the temperature of the flue gas, resulting in an increase in the temperature of the discharged flue gas. No condensate is generated, thus avoiding corrosion of the low-temperature plate heat exchanger and the exhaust fan of the hot blast stove.

[0050] In summer, when the flue gas temperature is high, rotating the valve stem 42 causes the valve plate 41 to rise, sequentially opening several flue gas passages of the low-temperature plate heat exchanger 3 to participate in heat exchange. All flue gas passages of the low-temperature plate heat exchanger 3 fully participate in heat exchange, reducing the flue gas temperature. This makes the flue gas temperature of the hot blast stove adjustable, which can avoid low-temperature corrosion and condensate generation, and ensure that the thermal efficiency of the hot blast stove can be maintained above 95% regardless of winter or summer.

[0051] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. An adjustable flue gas temperature hot air furnace, comprising a hot air furnace frame (1), characterized in that: The hot air furnace frame (1) is internally equipped with a high-temperature plate heat exchanger (2) and a low-temperature plate heat exchanger (3), and the air passage of the high-temperature plate heat exchanger (2) and the air passage of the low-temperature plate heat exchanger (3) are connected. The flue gas passages of the high-temperature plate heat exchanger (2) and the low-temperature plate heat exchanger (3) are connected by an adjustable lift valve (4). The heating component (5) of the high-temperature plate heat exchanger (2) is used to inject and discharge hot flue gas and hot air into the high-temperature plate heat exchanger (2) respectively.

2. The adjustable flue gas temperature hot air furnace according to claim 1, characterized in that: The heating assembly (5) includes an outer cylinder (51) fixed inside the hot air furnace frame (1), and a combustion chamber (52) is fixed inside the outer cylinder (51). A burner interface (53) is installed at one end of the combustion chamber (52). The left ends of the combustion chamber (52) and the outer cylinder (51) are respectively connected to the flue gas passage and air passage of the high-temperature plate heat exchanger (2). The front end of the hot air furnace frame (1) is provided with a cold end outlet (54), and the rear end of the cold end outlet (54) is connected to the outer cylinder (51).

3. The adjustable flue gas temperature hot air furnace according to claim 1, characterized in that: The flue gas passages of the low-temperature plate heat exchanger (3) and the high-temperature plate heat exchanger (2) are both horizontal slits arranged vertically. The right end face of the valve plate (41) of the adjustable lifting valve (4) is slidably connected to the flue gas passage of the low-temperature plate heat exchanger (3), and the descending valve plate (41) blocks several flue gas passages from top to bottom.

4. The adjustable flue gas temperature hot air furnace according to claim 2, characterized in that: The gaps between the hot air furnace frame (1) and the outer cylinder (51), the high-temperature plate heat exchanger (2) and the low-temperature plate heat exchanger (3) are filled with an insulation layer (6).

5. The adjustable flue gas temperature hot air furnace according to claim 2, characterized in that: The left end of the combustion chamber (52) is connected to the flue gas passage of the high-temperature plate heat exchanger (2) through a bend duct (55), and both the bend duct (55) and the middle of the combustion chamber (52) are provided with expansion corrugated cylinders (56).

6. The adjustable flue gas temperature hot air furnace according to claim 1, characterized in that: The flue gas passage and air passage of the low-temperature plate heat exchanger (3) are respectively provided with a flue gas outlet (31) and a cold side inlet (32), and the bottom and top of the cold side inlet (32) are respectively provided with a condensate outlet (33) and a flue gas temperature monitoring port (34), and a high-temperature thermocouple is installed in the flue gas temperature monitoring port (34).

7. The adjustable flue gas temperature hot air furnace according to claim 3, characterized in that: The valve stem (42) of the adjustable lift valve (4) is provided with a high-temperature transmission blocking structure (43), the valve plate (41) is made of cast heat-resistant stainless steel, and the valve frame (44) of the adjustable lift valve (4) is provided with a high-temperature deformation prevention frame (45).

8. The adjustable flue gas temperature hot air furnace according to claim 2, characterized in that: The outer wall of the combustion chamber (52) is fitted with a baffle plate (57) located in the middle of the outer cylinder (51), and the outer wall of the baffle plate (57) is fixedly connected to the outer cylinder (51). The rear end of the baffle plate (57) is provided with a notch for air circulation.

9. The adjustable flue gas temperature hot air furnace according to claim 2, characterized in that: The top of the outer cylinder (51) is provided with a furnace temperature monitoring port (21) located on the left side of the high-temperature plate heat exchanger (2), and a high-temperature thermocouple is installed in the furnace temperature monitoring port (21).

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