Cooling device for dilute nitric acid production and cooling method thereof

Abstract

The invention provides a cooling device for dilute nitric acid production and a cooling method thereof, and relates to the technical field of dilute nitric acid production, the cooling device comprises a waste heat driven absorption type refrigeration module, a refrigerant energy storage box and an air-liquid cooling integrated system, the waste heat driven absorption type refrigeration module recovers and refrigerates tail gas waste heat produced by an oxidation furnace, and cold energy is conveyed to the refrigerant energy storage box; the air-liquid cooling integrated system comprises a driving module, an air cooling box, liquid cooling coil pipe cooling clamping plates and an isolation sleeve, the two cooling clamping plates are oppositely distributed, the upper ends and the lower ends of the cooling clamping plates are fixedly connected into an integrated structure through end rings, and the cooling clamping plates are vertically and rotatably hung on the outer wall of the absorption tower. By means of the air-liquid cooling integrated system, efficient cooling of a thermal medium is achieved, the effect of improving the production efficiency is achieved, the contact area and the heat exchange efficiency between the thermal medium and a cooling medium are greatly increased through the structure, rapid cooling of the thermal medium in an absorption tower is guaranteed, and therefore the overall efficiency of dilute nitric acid production is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of dilute nitric acid production, in particular to a cooling device for dilute nitric acid production and a cooling method thereof. Background Art

[0002] In the production process of dilute nitric acid, cooling equipment plays a vital role. Traditional cooling technologies mainly rely on direct cooling systems, such as air coolers or water coolers, which remove heat from the production process through the flow of air or water. Among them, air coolers use natural wind or forced ventilation to cool the heat medium, and usually adopt the method of delivering cooling air from the middle of the spiral circulation tube for cooling. Not only is the return temperature difficult to control, but the cooling efficiency is also low. Water coolers remove heat through the water circulation system and dissipate it into the atmosphere. However, these traditional cooling methods have obvious limitations. For example, air coolers are limited by environmental conditions such as air temperature and wind speed, and their cooling efficiency is often greatly affected; water coolers require a large amount of water resources and may cause secondary pollution. Summary of the Invention

[0003] The purpose of the present invention is to make up for the shortcomings of the existing technology and propose a cooling device and a cooling method for dilute nitric acid production. Through the coordinated control of waste heat recovery and gas-liquid dual-effect cooling, the technical problems of high energy consumption and slow response of traditional cooling systems are solved.

[0004] To solve the above technical problems, the present invention provides the following technical solutions: a cooling device for dilute nitric acid production and a cooling method thereof, comprising a waste heat-driven absorption refrigeration module, a refrigerant energy storage tank, and an air-liquid cooling integrated system. The waste heat-driven absorption refrigeration module recovers the waste heat of the tail gas produced by the oxidation furnace and refrigerates it, and transmits the cold energy to the refrigerant energy storage tank; The air-liquid cooling integrated system includes a drive module, an air cooling box, a liquid cooling coil, a cooling splint and an isolation sleeve. There are two cooling splints distributed relatively to each other, and the upper and lower ends are fixedly connected to form an integrated structure by end rings. The cooling splint is vertically rotatably mounted on the outer wall of the absorption tower, and the air cooling box is fixedly mounted at one end between the two cooling splints; the circulation pipe on the absorption tower is driven by a circulation pump from bottom to top, and the lifting section of the circulation pipe is a spiral structure located in the middle of the two cooling splints. The spiral section of the circulation pipe has an isolation sleeve vertically clamped in the inner cavity, and the isolation sleeve is spirally provided with a liquid cooling coil; the drive module transports the coolant in the refrigerant energy storage box to the liquid cooling coil to cool and circulate the circulation pipe, and the drive module draws external air and transports it to the air cooling box through the inner cavity of the refrigerant energy storage box for air cooling, and simultaneously drives the cooling splint to rotate and swing back and forth with the circulation pipe as the rotation axis.

[0005] Optionally, the waste heat driven absorption refrigeration module includes a waste heat recovery unit directly connected to the exhaust gas outlet flange of the oxidation furnace, an ammonia absorption refrigerator and a heat pipe heat exchanger. The waste heat recovery unit and the ammonia absorption refrigerator are connected through a heat pipe heat exchanger. The heat pipe heat exchanger transfers the absorbed heat to the ammonia absorption refrigerator. A refrigeration pipe for conducting low temperature is provided between the ammonia absorption refrigerator and the refrigerant energy storage tank, and the refrigeration pipe passes through the inner cavity of the refrigerant energy storage tank.

[0006] A hanging rod is vertically provided on the tower wall of the absorption tower, and a group of retaining rings are respectively provided at the upper and lower ends of the hanging rod. Hanging sleeves are respectively fixed at the upper and lower ends of the side walls of the cooling splint opposite to the hanging rod, and an arc-shaped movable hole is opened on the hanging sleeve. The hanging rod passes through the movable hole and is stopped by the retaining ring.

[0007] Optionally, the driving module includes a motor, a driving rod, a liquid-cooled piston cylinder, an air-cooled piston cylinder, a rocking gear plate, a rocker arm and a conversion plate. The motor drives the driving rod to rotate, one end of the driving rod passes through the refrigerant energy storage tank and out, and the driving rod is also rotatably connected to two piston rods, the two piston rods respectively corresponding to the liquid-cooled piston cylinder and the air-cooled piston cylinder. Under the action of the piston rod, the liquid-cooled piston cylinder pumps the coolant in the refrigerant energy storage tank into the liquid-cooled coil in one direction, and the air-cooled piston cylinder transports external air to the air-cooled box in one direction through the air pipe passing through the refrigerant energy storage tank. There are also evenly spaced brushes distributed in a ring on the driving rod in the refrigerant energy storage tank, and the brushes are immersed in the coolant. The brushes rotate with the driving rod to drive the coolant mixing and clean the refrigeration pipe below and the air pipe surface of the air-cooled piston cylinder; The rocking gear disc is a semicircular gear disc structure, one end of the rocking gear disc corresponds to the end ring at the lower end, and the end ring at the lower end is provided with an arc-shaped ring tooth that meshes with the rocking gear disc, and the other end of the rocking gear disc is fixedly connected to the rocker arm, and a movable bar hole is vertically penetrated on the part of the rocker arm near the end, and the bottom of the rocker arm is a conversion disc, and an axle pin is vertically provided at a position near the edge of the upper end surface of the conversion disc, and the axle pin passes through the movable bar hole, and the lower end of the rotating shaft of the conversion disc is fixedly connected with a worm disc, and the part of the driving rod corresponding to the worm disc is a meshing worm segment, and the rotation of the driving rod synchronously drives the conversion disc to rotate, and the conversion disc drives the rocking gear disc to swing and rotate, and the ring tooth drives the cooling splint part to rotate 0-60 degrees.

[0008] Optionally, the middle parts of the two cooling splints are both convex arc-shaped structures, and two rows of comb teeth are vertically provided on the inner wall of the arc-shaped part of the cooling splint. A gap for air to pass through is left between the circulation pipe coiled on the isolation sleeve and the inner wall of the cooling splint. The ends of the comb teeth are in contact with the circulation pipe, and the low-temperature air from the air-cooled box flows along the interlayer gap, wraps around the circulation pipe and passes through.

[0009] Optionally, the air inlet pipe connected to the air-cooled piston cylinder is coiled in a serpentine state in the inner cavity of the refrigerant energy storage box, and its end passes through the top of the refrigerant energy storage box, and the refrigeration pipe in the refrigerant energy storage box is distributed in a braided and entangled state with the air inlet pipe.

[0010] Optionally, the air-cooling box is an isosceles trapezoidal structure that is wider at one end toward the isolation sleeve. The low-temperature air delivered enters through the narrow end of the air-cooling box. A number of diverter plates are distributed in a fan shape on the variable diameter cavity part of the air-cooling box. The air-cooling box separates the delivered air into multiple channels. The diverter plates are provided with energy storage protrusions. The ends of the diverter plates are fixedly connected to horizontally placed upper and lower evenly spaced companion fins through connecting plates to the outside of the air-cooling box. There is a gap between the flared end of the air-cooling box and the inner walls of the two cooling splints. When the low-temperature air in the air-cooling box is ejected, it drives the air in the gap area to synchronously pass through the companion fins and follow the flow into the circulation pipe area.

[0011] Optionally, the upper end of the liquid cooling coil is connected to the liquid cooling piston cylinder through a lifting pipe, and the lower end of the liquid cooling coil is reflux connected to the refrigerant energy storage tank, and the coolant flow path of the liquid cooling coil in the isolation sleeve is from top to bottom.

[0012] Optionally, a spiral inner guide plate is provided in the inner cavity of the isolation sleeve along the bottom of the liquid cooling coil, and both the inner guide plate and the isolation sleeve are made of high thermal conductivity materials.

[0013] The cooling method of the cooling device for producing dilute nitric acid comprises the following steps: S1. Waste heat recovery and refrigeration: This waste heat is used to drive an absorption refrigeration module to recover waste heat from the exhaust gas produced by the oxidation furnace. The waste heat recovery unit captures the heat in the exhaust gas and transfers it to an ammonia absorption chiller via a heat pipe heat exchanger. The ammonia absorption chiller uses the captured heat to generate low-temperature coolant, which is then transported through refrigeration pipes to a refrigerant energy storage tank for storage. S2. Start the motor in the drive module, driving the drive rod to rotate. The drive rod drives the liquid-cooled piston cylinder and the air-cooled piston cylinder respectively through the piston rod. The liquid-cooled piston cylinder pumps the coolant from the refrigerant energy storage tank unidirectionally into the liquid-cooled coil, cooling the circulation pipe located in the isolation sleeve. The coolant flows in the liquid-cooled coil in a top-in, bottom-out manner, ensuring effective heat exchange. Simultaneously, the air-cooled piston cylinder delivers external air unidirectionally to the air-cooled box through the air pipe for air cooling. In the air-cooled box, the low-temperature air is guided and enhanced by the manifold and associated fins, and evenly sprayed into the area between the two cooling plates, further cooling the circulation pipe. S3. When the drive rod rotates, the worm segment drives the conversion plate, which, through the shaft pin and the movable bar hole, drives the rocker arm and the rocking gear plate to swing. The rocking gear plate engages with the ring gear on the end ring at the lower end, driving the cooling splint to rotate back and forth 0-60 degrees around the circulation tube as the rotation axis, enhancing the cooling effect. S4. The circulation pipe is driven through the absorption tower by a circulation pump. Its lifting section is a spiral structure located between the two cooling plates. The heat medium in the circulation pipe is cooled by the dual cooling effects of the liquid cooling coil and low-temperature air. Furthermore, the middle of the cooling plate has an outwardly convex arc structure, leaving a gap for air to pass between the circulation pipe coiled around the isolation sleeve, further promoting heat exchange. S5. After the coolant completes its cooling task in the liquid cooling coil, it flows back to the refrigerant energy storage tank, ready for the next cycle. The outside air drawn into the air-cooled piston cylinder is further cooled by the serpentine air inlet pipe and the braided winding area of ​​the cooling tube within the refrigerant energy storage tank, and then delivered to the air cooling tank. S6. The brush on the drive rod rotates with the drive rod, which not only drives the coolant to mix, but also cleans the surface of the refrigeration pipe below and the air pipe connected to the air-cooled piston cylinder to prevent blockage and fouling.

[0014] Compared with the prior art, the cooling device and cooling method for producing dilute nitric acid have the following beneficial effects: 1. The present invention drives the absorption refrigeration module through waste heat, realizes the efficient recovery and utilization of tail gas waste heat, and achieves the effect of energy saving and emission reduction.

[0015] 2. The air-liquid cooling integrated system achieves efficient cooling of the heat medium and improves production efficiency. The air-liquid cooling integrated system combines air cooling and liquid cooling. The heat medium in the circulation pipe is initially cooled by the liquid cooling coil, and then the low-temperature air in the air cooling box performs secondary cooling on the circulation pipe from one side. This greatly increases the contact area and heat exchange efficiency between the heat medium and the cooling medium, ensures the rapid cooling of the heat medium in the absorption tower, and thus improves the overall efficiency of dilute nitric acid production.

[0016] 3. The drive module realizes the reciprocating rotation and swinging of the cooling splint, thereby achieving the purpose of enhancing the cooling effect and heat exchange uniformity. The motor in the drive module drives the drive rod to rotate, and converts the rotational motion into the reciprocating rotation and swinging of the cooling splint through a series of transmission mechanisms. This design not only increases the relative movement between the cooling splint and the circulation pipe, improving the uniformity of heat exchange, but also further enhances the cooling effect by changing the angle and position of the cooling splint, so that the heat medium can more fully exchange heat with the cooling medium. In the process of the cooling splint rotating and swinging back and forth with the swinging gear disk, the cooling airflow can completely wrap the entire circulation pipe, avoiding dead corners and improving cooling efficiency. In this process, the comb teeth can clean the surface of the circulation pipe to prevent wall hanging and dirt from affecting the cooling effect. At the same time, the comb teeth can also disperse the cooling airflow evenly, ensuring that the airflow can be blown evenly from one side to the circulation pipe, so that the dilute nitric acid solution in the circulation pipe can be cooled at the same temperature in the entire section during the transportation from bottom to top, and can achieve step-by-step continuous cooling to ensure that the reflux temperature at the top is always stable. Compared with the existing method of vertically blowing air from the cavity of the spiral circulation pipe for cooling, the cooling efficiency is higher and the reflux temperature control is more accurate.

[0017] 4. The brush structure cleans the surfaces of the refrigeration pipes and gas pipes, preventing blockage and fouling while improving heat exchange efficiency. The circular brush structure on the drive rod continuously cleans the surfaces of the refrigeration pipes and gas pipes below as the drive rod rotates. This design effectively prevents dirt from adhering to the pipe surfaces and clogging them, ensuring unobstructed heat exchange channels, thereby improving heat exchange efficiency and extending the service life of the equipment.

[0018] 5. The serpentine-shaped, braided structure of the air inlet and cooling tubes pre-cools the incoming air, improving cooling efficiency and reducing energy consumption. The serpentine-shaped, braided structure of the air inlet and cooling tubes within the refrigerant energy storage box pre-cools the outside air before it enters the cooling box. This design not only improves cooling efficiency but also provides a lower-temperature air source for the subsequent cooling process, thereby reducing energy consumption for the entire cooling system.

[0019] Other advantages, objects and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art based on an examination of the following or may be learned from the practice of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention from a first axis view; Figure 2This is a schematic diagram of the three-dimensional structure of the present invention from a second axis; Figure 3 This is a schematic structural diagram of the refrigerant energy storage box, air-cooling box and cooling clamping plate portion of the present invention from a first axial perspective; Figure 4 This is a schematic structural diagram of the refrigerant energy storage box, air-cooling box and cooling clamping plate portion according to the present invention from a second axial view; Figure 5 This is a schematic diagram of the structure of the outer cooling clamping plate of the present invention when it is removed from the axis; Figure 6 This is a schematic diagram of the axial structure of the air cooling box shell in a half-cut and separated state of the present invention; Figure 7 For the present invention Figure 6 A in the middle is a schematic diagram of the structure of the enlarged part; Figure 8 This is a schematic diagram of the cross-section of the circulation pipe and the isolation sleeve of the present invention; Figure 9 This is a partial axial structural diagram of the drive module and refrigerant energy storage box of the present invention.

[0021] Figure 10 This is a structural block diagram of the waste heat driven absorption refrigeration module of the present invention.

[0022] In the picture: 1. Waste heat driven absorption refrigeration module; 101. Waste heat recovery unit; 102. Ammonia absorption refrigerator; 103. Heat pipe heat exchanger; 2. Absorption tower; 201. Circulation pipe; 202. Hanging rod; 2021. Retaining ring; 3. Refrigerant energy storage tank; 301. Refrigeration pipe; 4. Circulation pump; 5. Drive module; 501. Motor; 502. Drive rod; 5021. Worm segment; 5022. Piston rod; 5023. Brush; 503. Liquid-cooled piston cylinder; 504. Air-cooled piston cylinder; 505. Rocker gear; 506. Rocker arm; 5061. Movable bar hole; 507. Conversion plate; 5071. Worm; 5072. Axle pin; 6. Air cooler; 601. Diverter plate; 6011. Energy storage protrusion; 602. Associated fin; 7. Liquid cooling coil; 701. Riser; 8. Cooling splint; 801. End ring; 8011. Ring teeth; 802. Hanging sleeve; 8021. Movable hole; 803. Comb teeth; 9. Isolation sleeve; 901. Inner guide. DETAILED DESCRIPTION

[0023] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0024] See also Figures 1 to 10 The present invention provides the following embodiments: a cooling device for dilute nitric acid production and a cooling method thereof, comprising: a waste heat-driven absorption refrigeration module 1, a refrigerant energy storage tank 3, and an air-liquid cooling integrated system, wherein the waste heat-driven absorption refrigeration module 1 recovers the waste heat of the tail gas produced by the oxidation furnace and refrigerates the exhaust gas, and transmits the cold energy to the refrigerant energy storage tank 3; A hanging rod 202 is vertically provided on the tower wall of the absorption tower 2. A set of retaining rings 2021 are respectively provided at the upper and lower ends of the hanging rod 202. Hanging sleeves 802 are respectively fixed at the upper and lower ends of the side walls of the cooling splint 8 opposite to the hanging rod 202. The hanging sleeves 802 are provided with arc-shaped movable holes 8021. The hanging rod 202 passes through the movable holes 8021 and is stopped by the retaining rings 2021. The air-liquid cooling integrated system includes a drive module 5, an air cooling box 6, a liquid cooling coil 7, a cooling splint 8 and an isolation sleeve 9. There are two cooling splints 8 that are relatively distributed, and the upper and lower ends are fixedly connected to form an integrated structure through end rings 801. The cooling splint 8 is vertically rotated and hung on the outer wall of the absorption tower 2. The air cooling box 6 is fixedly installed at one end between the two cooling splints 8. The circulation pipe 201 on the absorption tower 2 is circulated and driven from bottom to top by the circulation pump 4. The lifting section of the circulation pipe 201 is a spiral structure. The structure is located in the middle of the two cooling splints 8, and an isolation sleeve 9 is vertically clamped in the inner cavity of the spiral section of the circulation pipe 201; a liquid cooling coil 7 is spirally provided in the isolation sleeve 9; the driving module 5 transports the coolant in the refrigerant energy storage tank 3 to the liquid cooling coil 7 to cool and circulate the circulation pipe 201, and the driving module 5 draws the external air and transports it through the inner cavity of the refrigerant energy storage tank 3 to the air cooling box 6 for air cooling, and simultaneously drives the cooling splint 8 to rotate and swing back and forth with the circulation pipe 201 as the rotation axis.

[0025] The waste heat driven absorption refrigeration module 1 includes a waste heat recovery unit 101 directly connected to the exhaust flange of the oxidation furnace, an ammonia absorption refrigerator 102 and a heat pipe heat exchanger 103. The waste heat recovery unit 101 is connected to the ammonia absorption refrigerator 102 through the heat pipe heat exchanger 103. The heat pipe heat exchanger 103 transfers the absorbed heat to the ammonia absorption refrigerator 102. A refrigeration pipe 301 for conducting low temperature is provided between the ammonia absorption refrigerator 102 and the refrigerant energy storage tank 3. The refrigeration pipe 301 passes through the inner cavity of the refrigerant energy storage tank 3. The heat recovery unit 101 is directly connected to the exhaust gas outlet flange of the oxidation furnace, and can capture the heat in the exhaust gas. The heat pipe heat exchanger 103 connects the waste heat recovery unit 101 and the ammonia absorption refrigerator 102, and transfers the absorbed heat to the ammonia absorption refrigerator 102. The ammonia absorption refrigerator 102 uses the captured heat for cooling to produce low-temperature coolant. The refrigeration pipe 301 connects the ammonia absorption refrigerator 102 and the refrigerant energy storage tank 3, and is used to conduct low temperature. It passes through the inner cavity of the refrigerant energy storage tank 3 and transports the low-temperature coolant to the refrigerant energy storage tank 3 for storage.

[0026] Among them, the driving module 5 includes a motor 501, a driving rod 502, a liquid-cooled piston cylinder 503, an air-cooled piston cylinder 504, a rocking gear plate 505, a rocker arm 506 and a conversion plate 507. The motor 501 drives the driving rod 502 to rotate. One end of the driving rod 502 passes through the refrigerant energy storage box 3 and out. The driving rod 502 is also rotatably connected to two piston rods 5022. The two piston rods 5022 correspond to the liquid-cooled piston cylinder 503 and the air-cooled piston cylinder 504 respectively. The liquid-cooled piston cylinder 503 pushes the coolant in the refrigerant energy storage box 3 under the action of the piston rod 5022. The coolant is pumped unidirectionally into the liquid-cooling coil 7, and the air-cooling piston cylinder 504 delivers external air unidirectionally to the air-cooling box 6 through the air pipe passing through the refrigerant energy storage box 3. The driving rod 502 in the refrigerant energy storage box 3 is also annularly distributed with evenly spaced brushes 5023. The brushes 5023 are immersed in the coolant. The brushes 5023 rotate with the driving rod 502 to mix the coolant and clean the cooling pipe 301 below and the air pipe surface of the air-cooling piston cylinder 504, preventing dirt from adhering to the pipe surface and affecting the heat exchange, thereby improving the cooling efficiency and reducing the maintenance frequency. The swing tooth plate 505 is a semicircular tooth plate structure. One end of the swing tooth plate 505 corresponds to the end ring 801 at the lower end. The end ring 801 at the lower end is provided with an arc-shaped ring tooth 8011 that meshes with the swing tooth plate 505. The other end of the swing tooth plate 505 is fixedly connected to the rocker arm 506. A movable bar hole 5061 is vertically penetrated on the part near the end of the rocker arm 506. The lower part of the rocker arm 506 is a conversion plate 507. The upper end surface of the conversion plate 507 is close to the edge. An axle pin 5072 is vertically provided at the position, and the axle pin 5072 passes through the movable bar hole 5061. The lower end of the rotating shaft of the conversion disk 507 is fixedly connected to the worm 5071. The part of the driving rod 502 corresponding to the worm 5071 is the meshing worm segment 5021. The driving rod 502 rotates synchronously to drive the conversion disk 507 to rotate, and the conversion disk 507 drives the rocking gear plate 505 to rock and rotate. The ring gear 8011 drives the cooling splint 8 to rotate 0-60 degrees to enhance the cooling effect.

[0027] Among them, the middle parts of the two cooling splints 8 are both convex arc-shaped structures, and two rows of comb teeth 803 are vertically provided on the inner wall of the arc-shaped part of the cooling splint 8. A gap for air to pass through is left between the circulation pipe 201 coiled on the isolation sleeve 9 and the inner wall of the cooling splint 8. The end of the comb teeth 803 contacts the circulation pipe 201. The low-temperature air from the air-cooling box 6 flows along the interlayer gap and wraps around the circulation pipe 201 and passes through. In the process of the cooling splint 8 reciprocatingly rotating and swinging with the swinging tooth plate 505, the cooling air flow can completely wrap the entire circulation pipe 201. Tube 201, avoid dead corners and improve cooling efficiency. In this process, the comb teeth 803 can clean the surface of the circulation tube 201 to avoid wall hanging and dirt affecting the cooling effect. At the same time, the comb teeth 803 can also disperse the cooling airflow evenly, ensuring that the airflow blowing from one side to the circulation tube 201 can be uniform, so that the dilute nitric acid solution in the circulation tube 201 can be cooled at the same temperature in the entire section during the process of being transported from bottom to top, and can achieve step-by-step continuous cooling to ensure that the reflux temperature at the top is always stable.

[0028] Among them, the air inlet pipe connected to the air-cooling piston cylinder 504 is in a serpentine coiled state in the inner cavity of the refrigerant energy storage box 3, and its end passes through the top of the refrigerant energy storage box 3, and the refrigeration pipe 301 in the refrigerant energy storage box 3 is distributed in a braided and entangled state with the air inlet pipe, which helps to improve the cooling efficiency of the inhaled air and improve the exchange efficiency.

[0029] Among them, the air-cooling box 6 is an isosceles trapezoidal structure that is wider at one end toward the isolation sleeve 9. The low-temperature air delivered enters through the narrow end of the air-cooling box 6. A number of diverter plates 601 are distributed in a fan shape on the variable diameter cavity part of the air-cooling box 6. The air-cooling box 6 separates the delivered air into multiple channels. The diverter plates 601 are provided with energy storage protrusions 601. The ends of the diverter plates 601 are fixedly connected to the outside of the air-cooling box 6 through connecting plates and are horizontally placed with evenly spaced upper and lower associated fins 602. There is a gap between the flared end of the air-cooling box 6 and the inner walls of the two cooling splints 8. When the low-temperature air in the air-cooling box 6 is ejected, it drives the air in the gap area to synchronously pass through the associated fins 602 and follow the flow into the circulation pipe 201 area, thereby realizing air cooling of the circulation pipe 201.

[0030] Among them, the upper end of the liquid cooling coil 7 is connected to the liquid cooling piston cylinder 503 through the lifting pipe 701, and the lower end of the liquid cooling coil 7 is refluxed and connected to the refrigerant energy storage tank 3. The coolant flow path of the liquid cooling coil 7 in the isolation sleeve 9 is from top to bottom, ensuring effective heat exchange.

[0031] Among them, a spiral inner guide plate 901 is provided in the inner cavity of the isolation sleeve 9 along the bottom of the liquid cooling coil 7. The inner guide plate 901 and the isolation sleeve 9 are both made of high thermal conductivity materials, which helps to improve the heat exchange efficiency.

[0032] The cooling method of the cooling device for producing dilute nitric acid comprises the following steps: S1. Waste heat recovery and refrigeration: The waste heat is used to drive the absorption refrigeration module 1 to recover the waste heat from the exhaust gas produced by the oxidation furnace. The waste heat recovery unit 101 captures the heat in the exhaust gas and transfers the heat to the ammonia absorption refrigerator 102 via the heat pipe heat exchanger 103. The ammonia absorption refrigerator 102 uses the captured heat to generate low-temperature coolant, which is then transported to the refrigerant energy storage tank 3 for storage via the refrigeration pipe 301. S2. Start the motor 501 in the drive module 5 to drive the drive rod 502 to rotate. The drive rod 502 drives the liquid-cooled piston cylinder 503 and the air-cooled piston cylinder 504 respectively through the piston rod 5022. The liquid-cooled piston cylinder 503 pumps the coolant in the refrigerant energy storage tank 3 into the liquid-cooled coil 7 in a unidirectional manner to cool the circulation pipe 201 located in the isolation sleeve 9. The flow path of the coolant in the liquid-cooled coil 7 is from top to bottom, ensuring effective heat exchange. At the same time, the air-cooled piston cylinder 504 transports external air to the air-cooled box 6 in a unidirectional manner through the air pipe for air cooling. The low-temperature air in the air-cooled box 6 is guided and enhanced by the diverter plate 601 and the associated fins 602, and is evenly sprayed into the area between the two cooling clamping plates 8, further cooling the circulation pipe 201; S3. When the drive rod 502 rotates, the worm segment 5021 drives the conversion plate 507 to rotate. The conversion plate 507 drives the rocker arm 506 and the rocking gear plate 505 to rock and rotate through the shaft pin 5072 and the movable bar hole 5061. The rocking gear plate 505 engages with the ring gear 8011 on the end ring 801 at the lower end, driving the cooling splint 8 to rotate and swing back and forth 0-60 degrees around the circulation tube 201 as the rotation axis, enhancing the cooling effect. S4. Circulation pipe 201 is driven by a circulation pump 4 to circulate through absorption tower 2. Its lifting section is a spiral structure located midway between two cooling plates 8. The heat medium in circulation pipe 201 is cooled by both the liquid cooling coil 7 and the low-temperature air. Furthermore, the middle portion of cooling plate 8 is an outwardly convex arc-shaped structure, leaving a gap for air to pass between the circulation pipe 201, which is coiled around the isolation sleeve 9, further promoting heat exchange. S5. After the coolant completes its cooling task in the liquid cooling coil 7, it flows back to the refrigerant energy storage tank 3, ready for the next cycle. The external air inhaled by the air-cooled piston cylinder 504 is further cooled in the inner cavity of the refrigerant energy storage tank 3 through the serpentine air inlet pipe and the braided winding area of ​​the cooling tube 301, and then transported to the air cooling tank 6; S6. The brush 5023 on the drive rod 502 rotates with the drive rod 502, not only driving the coolant to mix, but also brushing the surface of the refrigeration pipe 301 below and the air pipe connected to the air-cooled piston cylinder 504 to prevent blockage and fouling.

[0033] Working Principle: The core of the device lies in the waste heat-driven absorption refrigeration module 1, which is directly connected to the exhaust gas outlet flange of the oxidation furnace via the waste heat recovery unit 101, effectively capturing the heat contained in the exhaust gas. This heat is then efficiently transferred to the ammonia absorption chiller 102 via the heat pipe heat exchanger 103. Inside the ammonia absorption chiller 102, the captured heat drives the refrigeration cycle, producing low-temperature coolant. This low-temperature coolant is then transported via the refrigerant pipe 301 to the refrigerant energy storage tank 3 for storage and subsequent use in the cooling process.

[0034] The refrigerant energy storage tank 3 not only serves as a coolant storage container, but also further enhances cooling efficiency through its internal structure. Within the tank, a serpentine-shaped air inlet pipe interweaves with the refrigerant tube 301, forming a unique cooling channel. When external air is drawn into the air-cooled piston cylinder 504 and delivered to the refrigerant energy storage tank 3, it passes through this cooling channel, where it is further cooled by the low-temperature coolant and the refrigerant tube 301. This design not only improves air cooling efficiency but also provides a lower-temperature air source for the subsequent air cooling process.

[0035] The key to achieving efficient cooling of the heat medium is the integrated air-liquid cooling system. This system includes components such as an air-cooling box 6, a liquid-cooling coil 7, cooling plates 8, and an isolation sleeve 9. The cooling plates 8 are vertically mounted on the outer wall of the absorption tower 2, creating a mezzanine space within them that provides a channel for air flow. The circulation pipe 201, serving as the heat medium transmission conduit, features a spiral structure at its lifting section, located between the two cooling plates 8. This design not only increases the contact area between the heat medium and the cooling medium, but also improves heat exchange efficiency.

[0036] The liquid cooling coil 7 is spirally mounted inside the insulating sleeve 9, and its coolant is supplied by the refrigerant storage tank 3. As the coolant flows through the liquid cooling coil 7, it absorbs heat from the heat medium in the circulation pipe 201, achieving primary cooling. Simultaneously, the air-cooling piston cylinder 504 delivers the air cooled by the refrigerant storage tank 3 to the air-cooling box 6. Inside the air-cooling box 6, the air is guided and enhanced by the diverter plate 601 and associated fins 602, and evenly sprayed into the area between the two cooling plates 8, providing secondary cooling for the circulation pipe 201. This combined air-liquid cooling method ensures efficient cooling of the heat medium.

[0037] In addition, the design of the drive module 5 is also quite ingenious. The motor 501 drives the drive rod 502 to rotate, thereby driving the liquid-cooled piston cylinder 503 and the air-cooled piston cylinder 504 to respectively realize the delivery of coolant and the intake and discharge of air. At the same time, the worm segment 5021 on the drive rod 502 engages with the worm disc 5071 on the conversion disc 507, realizing the conversion of the rotation of the drive rod 502 to the swinging rotation of the swinging gear disc 505. The swinging gear disc 505 engages with the ring teeth 8011 on the end ring 801 at the lower end of the cooling splint 8, driving the cooling splint 8 to rotate and swing back and forth 0-60 degrees with the circulation tube 201 as the rotation axis. This design not only enhances the cooling effect, but also improves the uniformity of heat exchange.

[0038] It's worth noting that the drive rod 502 is also circularly distributed with evenly spaced brushes 5023. As the drive rod 502 rotates, these brushes 5023 not only mix the coolant but also clean the cooling tube 301 below and the air pipe connected to the air-cooling piston cylinder 504. This design effectively prevents dirt from adhering to the pipe surfaces, ensuring efficient heat exchange and reducing maintenance frequency.

[0039] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A cooling device for producing dilute nitric acid, characterized in that: include: The waste heat-driven absorption refrigeration module (1), the refrigerant energy storage tank (3) and the air-liquid cooling integrated system, wherein the waste heat-driven absorption refrigeration module (1) recovers the waste heat of the tail gas produced by the oxidation furnace for refrigeration and transmits the cold energy to the refrigerant energy storage tank (3); The air-liquid cooling integrated system comprises a drive module (5), an air cooling box (6), a liquid cooling coil (7), a cooling splint (8) and an isolation sleeve (9), wherein the cooling splints (8) are arranged in two opposite directions, and the upper and lower ends are fixedly connected to form an integrated structure through end rings (801), the cooling splints (8) are vertically rotatably mounted on the outer wall of the absorption tower (2), and the air cooling box (6) is fixedly mounted at one end between the two cooling splints (8); The circulation pipe (201) on the absorption tower (2) is driven by the circulation pump (4) from bottom to top, the lifting section of the circulation pipe (201) is a spiral structure located in the middle of the two cooling clamping plates (8), and an isolation sleeve (9) is vertically clamped in the inner cavity of the spiral section of the circulation pipe (201), and a liquid cooling coil (7) is spirally provided in the isolation sleeve (9); The driving module (5) transports the coolant in the refrigerant energy storage tank (3) to the liquid cooling coil (7) to cool and circulate the circulation tube (201). The driving module (5) draws in external air and transports it through the inner cavity of the refrigerant energy storage tank (3) to the air cooling box (6) for air cooling. Simultaneously, it also drives the cooling splint (8) to rotate and swing back and forth with the circulation tube (201) as the rotation axis.

2. A cooling device for producing dilute nitric acid according to claim 1, characterized in that: The waste heat driven absorption refrigeration module (1) comprises a waste heat recovery unit (101) directly connected to the exhaust outlet flange of the oxidation furnace, an ammonia absorption refrigeration machine (102) and a heat pipe heat exchanger (103). The waste heat recovery unit (101) and the ammonia absorption refrigeration machine (102) are connected via the heat pipe heat exchanger (103). The heat pipe heat exchanger (103) transfers the absorbed heat to the ammonia absorption refrigeration machine (102). A refrigeration pipe (301) for conducting low temperature is provided between the ammonia absorption refrigeration machine (102) and the refrigerant energy storage tank (3). The refrigeration pipe (301) passes through the inner cavity of the refrigerant energy storage tank (3).

3. A cooling device for producing dilute nitric acid according to claim 1, characterized in that: A hanging rod (202) is vertically provided on the tower wall of the absorption tower (2), and a group of retaining rings (2021) are respectively provided at the upper and lower ends of the hanging rod (202). Hanging sleeves (802) are respectively fixedly provided at the upper and lower ends of the side walls of the cooling splint (8) opposite to the hanging rod (202), and an arc-shaped movable hole (8021) is opened on the hanging sleeve (802), and the hanging rod (202) passes through the movable hole (8021) and is stopped by the retaining ring (2021).

4. A cooling device for producing dilute nitric acid according to claim 2, characterized in that: The driving module (5) comprises a motor (501), a driving rod (502), a liquid-cooled piston cylinder (503), an air-cooled piston cylinder (504), a rocking gear plate (505), a rocker arm (506) and a conversion plate (507). The motor (501) drives the driving rod (502) to rotate. One end of the driving rod (502) passes through the refrigerant energy storage box (3) and exits. The driving rod (502) is also rotatably connected to two piston rods (5022). The two piston rods (5022) correspond to the liquid-cooled piston cylinder (503) and the air-cooled piston cylinder (504) respectively. The liquid-cooled piston cylinder (503) is Under the action of the piston rod (5022), the coolant in the refrigerant energy storage box (3) is pumped unidirectionally into the liquid cooling coil (7), and the air-cooling piston cylinder (504) transports the external air unidirectionally into the air-cooling box (6) through the air pipe passing through the refrigerant energy storage box (3). The driving rod (502) in the refrigerant energy storage box (3) is also provided with brushes (5023) distributed in a ring shape at even intervals. The brushes (5023) are immersed in the coolant. The brushes (5023) rotate with the driving rod (502) to mix the coolant and clean the refrigeration pipe (301) below and the air pipe surface of the air-cooling piston cylinder (504). The swing tooth plate (505) is a semicircular tooth plate structure. One end of the swing tooth plate (505) corresponds to the end ring (801) at the lower end. The end ring (801) at the lower end is provided with an arc-shaped ring tooth (8011) that meshes with the swing tooth plate (505). The other end of the swing tooth plate (505) is fixedly connected to the rocker arm (506). A movable bar hole (5061) is vertically penetrated on the part of the rocker arm (506) near the end. The lower part of the rocker arm (506) is a conversion plate (507). The upper end surface of the conversion plate (507) is close to the edge. An axle pin (5072) is vertically provided at the edge, and the axle pin (5072) passes through the movable bar hole (5061). The lower end of the rotating shaft of the conversion disk (507) is fixedly connected to the worm disk (5071). The part of the driving rod (502) corresponding to the worm disk (5071) is a meshing worm segment (5021). The driving rod (502) rotates synchronously to drive the conversion disk (507) to rotate, and the conversion disk (507) drives the swing gear disk (505) to swing and rotate, and the ring gear (8011) drives the cooling splint (8) to rotate 0-60 degrees.

5. A cooling device for producing dilute nitric acid according to claim 1, characterized in that: The middle parts of the two cooling splints (8) are both convex arc-shaped structures, and two rows of comb teeth (803) are vertically provided on the inner wall of the arc-shaped part of the cooling splint (8). A gap for air to pass through is left between the circulation pipe (201) coiled on the isolation sleeve (9) and the inner wall of the cooling splint (8). The ends of the comb teeth (803) are in contact with the circulation pipe (201), and the low-temperature air from the air cooling box (6) flows along the interlayer gap, wraps around the circulation pipe (201) and passes through.

6. A cooling device for producing dilute nitric acid according to claim 4, characterized in that: The air inlet pipe connected to the air-cooling piston cylinder (504) is coiled in a serpentine shape in the inner cavity of the refrigerant energy storage box (3), and its end passes through the top of the refrigerant energy storage box (3), while the refrigeration pipe (301) in the refrigerant energy storage box (3) and the air inlet pipe are distributed in a braided and entangled state.

7. A cooling device for producing dilute nitric acid according to claim 4, characterized in that: The air cooling box (6) is an isosceles trapezoidal structure with a wide end toward the isolation sleeve (9). The low-temperature air delivered enters through the narrow end of the air cooling box (6). A plurality of diverter plates (601) are distributed in a fan-shaped manner on the variable diameter cavity portion of the air cooling box (6). The air cooling box (6) separates the delivered air into multiple channels. The diverter plates (601) are provided with energy storage protrusions (6011). The ends of the diverter plates (601) are fixedly connected to the air cooling box (6) through connecting plates and are passed through the air cooling box (6) to the outside. There is a gap between the expanded end of the air cooling box (6) and the inner walls of the two cooling splints (8). When the low-temperature air in the air cooling box (6) is ejected, it drives the air in the gap area to pass through the accompanying fins (602) synchronously and follow the flow into the circulation pipe (201) area.

8. A cooling device for producing dilute nitric acid according to claim 4, characterized in that: The upper end of the liquid cooling coil (7) is connected to the liquid cooling piston cylinder (503) through the lifting pipe (701), and the lower end of the liquid cooling coil (7) is refluxed and connected to the refrigerant energy storage tank (3). The cooling liquid flow path of the liquid cooling coil (7) in the isolation sleeve (9) is from top to bottom.

9. A cooling device for producing dilute nitric acid according to claim 1, characterized in that: A spiral inner guide piece (901) is provided in the inner cavity of the isolation sleeve (9) along the bottom of the liquid cooling coil (7), and both the inner guide piece (901) and the isolation sleeve (9) are made of high thermal conductivity materials.

10. A cooling method for a cooling device for producing dilute nitric acid, applicable to the cooling device for producing dilute nitric acid according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Waste heat recovery and refrigeration, using waste heat to drive the absorption refrigeration module (1) to recover the waste heat of the exhaust gas produced by the oxidation furnace, capture the heat in the exhaust gas through the waste heat recovery unit (101), and transfer the heat to the ammonia absorption refrigeration machine (102) through the heat pipe heat exchanger (103), the ammonia absorption refrigeration machine (102) uses the captured heat to perform refrigeration, generate low-temperature coolant, and transfer the low-temperature coolant to the refrigerant energy storage tank (3) for storage through the refrigeration pipe (301); S2. Start the motor (501) in the drive module (5) to drive the drive rod (502) to rotate. The drive rod (502) drives the liquid-cooled piston cylinder (503) and the air-cooled piston cylinder (504) respectively through the piston rod (5022). The liquid-cooled piston cylinder (503) pumps the coolant in the refrigerant energy storage box (3) into the liquid-cooled coil (7) in one direction to cool the circulation pipe (201) located in the isolation sleeve (9). The flow path of the coolant in the liquid-cooled coil (7) is from top to bottom to ensure effective heat exchange. At the same time, the air-cooled piston cylinder (504) transports the external air to the air-cooled box (6) in one direction through the air pipe for air cooling. The low-temperature air passes through the guide and enhancement effect of the diverter plate (601) and the associated fin (602) in the air-cooled box (6) and is evenly sprayed to the area between the two cooling clamps (8) to further cool the circulation pipe (201). S3. When the driving rod (502) rotates, the worm segment (5021) drives the conversion disk (507) to rotate, and the conversion disk (507) drives the rocker arm (506) and the rocking toothed disk (505) to rock and rotate through the shaft pin (5072) and the movable bar hole (5061). The rocking toothed disk (505) is engaged with the ring teeth (8011) on the end ring (801) at the lower end, driving the cooling splint (8) to rotate and swing back and forth 0-60 degrees with the circulation tube (201) as the rotation axis, thereby enhancing the cooling effect; S4. The circulation pipe (201) is driven to circulate on the absorption tower (2) by the circulation pump (4). The lifting section is a spiral structure and is located in the middle of the two cooling clamps (8). The heat medium in the circulation pipe (201) is cooled by the dual cooling action of the liquid cooling coil (7) and the low-temperature air. At the same time, the middle part of the cooling clamp (8) is an outwardly convex arc structure, and a gap for air to pass is left between the circulation pipe (201) coiled on the isolation sleeve (9), thereby further promoting heat exchange. S5. After the coolant completes its cooling task in the liquid cooling coil (7), it flows back to the refrigerant energy storage tank (3) to prepare for the next cycle. The external air sucked into the air cooling piston cylinder (504) passes through the serpentine air inlet pipe and the braided winding area of ​​the refrigeration pipe (301) in the inner cavity of the refrigerant energy storage tank (3) and is further cooled and then transported to the air cooling tank (6); S6. The brush (5023) on the driving rod (502) rotates with the driving rod (502), not only driving the coolant to mix, but also brushing the cooling pipe (301) below and the surface of the air pipe connected to the air-cooling piston cylinder (504) to prevent blockage and fouling.

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