Cooling device for dilute nitric acid production and cooling method thereof

Abstract

The application provides a cooling device for dilute nitric acid production and a cooling method thereof, relates to the technical field of dilute nitric acid production, and comprises 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 tail gas waste heat generated by an oxidation furnace to produce refrigeration, and the cold energy is delivered to the refrigerant energy storage tank. The air-liquid cooling integrated system comprises a driving module, an air cooling tank, a liquid cooling coil cooling clamp and a separation sleeve. The two opposite ends of the cooling clamp are fixedly connected by end rings to form an integrated structure, and the cooling clamp is vertically hung on the outer wall of the absorption tower through vertical rotation. Through the air-liquid cooling integrated system, the heat medium is efficiently cooled, the production efficiency is improved, the contact area between the heat medium and the cooling medium and the heat exchange efficiency are greatly increased, the rapid cooling of the heat medium in the absorption tower is ensured, and the overall efficiency of the dilute nitric acid production is improved.

Description

TECHNICAL FIELD

[0001] The present application 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

[0002] In the production process of dilute nitric acid, the cooling device plays a crucial role. Traditional cooling techniques mainly rely on direct cooling systems, such as air coolers or water coolers, which use air or water flow to carry away the heat generated during the production process. Among them, the air cooler uses natural wind or forced ventilation to cool the hot medium, and usually adopts the mode of sending cooling air from the middle of the spiral circulating pipe to cool, which not only makes it difficult to control the backflow temperature, but also has low cooling efficiency. The water cooler, on the other hand, uses a water circulation system to carry away heat and dissipate it into the atmosphere. However, these traditional cooling methods have obvious limitations. For example, the cooling efficiency of the air cooler is often greatly affected by environmental conditions such as air temperature and wind speed; while the water cooler consumes a large amount of water resources and may cause secondary pollution. SUMMARY

[0003] The purpose of the present application is to make up for the shortcomings of the prior art, and to provide a cooling device for dilute nitric acid production and a cooling method thereof. Through the cooperation of waste heat recovery and gas-liquid double-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 application provides the following technical scheme: 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 tail gas waste heat generated by the oxidation furnace to produce refrigeration, and the cold energy is delivered to the refrigerant energy storage tank;

[0005] The air-liquid cooling integrated system comprises a driving module, an air cooling tank, a liquid cooling coil, two cooling clamps and an isolation sleeve, the two cooling clamps are oppositely distributed and fixedly connected by end rings at the upper and lower ends to form an integrated structure, the cooling clamps are vertically hung on the outer wall of the absorption tower, and the air cooling tank is fixedly installed at one end between the two cooling clamps; the circulating pipe on the absorption tower is driven by a circulating pump from bottom to top, the lifting section of the circulating pipe is in a spiral structure and located at the middle position of the two cooling clamps, the isolation sleeve is vertically clamped in the inner cavity of the spiral section of the circulating pipe, and the liquid cooling coil is spirally arranged in the isolation sleeve; the driving module delivers the cooling liquid in the refrigerant energy storage tank to the liquid cooling coil to cool and circulate the circulating pipe, the driving module sucks external air and delivers it to the air cooling tank through the inner cavity of the refrigerant energy storage tank for air cooling, and simultaneously drives the cooling clamps to reciprocally rotate and swing around the rotating shaft of the circulating pipe.

[0006] Optionally, the waste heat driven absorption refrigeration module comprises a waste heat recovery unit directly connected with the outlet flange of the oxidation furnace tail gas, an ammonia water absorption refrigeration machine and a heat pipe heat exchanger, the waste heat recovery unit is connected with the ammonia water absorption refrigeration machine through the heat pipe heat exchanger, the heat pipe heat exchanger transmits the absorbed heat to the ammonia water absorption refrigeration machine, and the ammonia water absorption refrigeration machine is provided with a refrigeration pipe for conducting low temperature between the ammonia water absorption refrigeration machine and the refrigerant energy storage tank.

[0007] The hanging rod is vertically arranged on the tower wall of the absorption tower, a group of retaining rings are arranged at the upper and lower ends of the hanging rod respectively, a hanging sleeve is fixedly arranged at the upper and lower ends of the side wall opposite to the hanging rod, an arc-shaped movable hole is formed in the hanging sleeve, the hanging rod passes through the movable hole and is stopped by the retaining ring.

[0008] Optionally, the driving module comprises a motor, a driving rod, a liquid cooling piston cylinder, an air cooling piston cylinder, a swing gear disc, a swing arm and a conversion disc, the motor drives the driving rod to rotate, one end of the driving rod penetrates through the refrigerant energy storage tank and extends out, the driving rod is further rotationally connected with two piston rods, the two piston rods correspond to the liquid cooling piston cylinder and the air cooling piston cylinder respectively, the liquid cooling piston cylinder unidirectionally pumps the cooling liquid in the refrigerant energy storage tank to the liquid cooling coil under the action of the piston rod, the air cooling piston cylinder unidirectionally transports external air to the air cooling tank through the air pipe penetrating through the refrigerant energy storage tank, and a plurality of brushes are annularly distributed on the driving rod in the refrigerant energy storage tank and are uniformly spaced, the brushes are immersed in the cooling liquid, and the brushes rotate with the driving rod to mix the cooling liquid and clean the refrigeration pipe below and the surface of the air pipe of the air cooling piston cylinder;

[0009] The swing gear disc is in a semicircular gear disc structure, one end of the swing gear disc corresponds to the end ring at the lower end, an arc-shaped ring tooth is arranged on the end ring at the lower end and engaged with the swing gear disc, the other end of the swing gear disc is fixedly connected with the swing arm, a movable strip hole is vertically and penetratingly formed in the part close to the end of the swing arm, the conversion disc is below the swing arm, a shaft pin is vertically arranged on the position close to the edge of the upper end surface of the conversion disc, the shaft pin passes through the movable strip hole, the lower end of the rotating shaft of the conversion disc is fixedly connected with a volute, the part corresponding to the volute on the driving rod is a worm segment engaged with the volute, the driving rod rotates to synchronously drive the conversion disc to rotate, the conversion disc drives the swing gear disc to swing and rotate, and the ring tooth drives the cooling clamp plate to rotate by 0-60 degrees.

[0010] Optionally, the middle part of each of the two cooling clamp plates is in an arc-shaped structure protruding outward, and two rows of comb teeth are vertically arranged on the inner wall of the arc-shaped part of the cooling clamp plate, a gap for air to pass through is left between the circulating pipe coiled on the isolation sleeve and the inner wall of the cooling clamp plate, the end of the comb tooth is in contact with the circulating pipe, and the low-temperature air from the air cooling tank flows along the interlayer gap, wraps the circulating pipe and passes through.

[0011] Optionally, the air inlet pipe connected with the air-cooled piston cylinder is coiled in a serpentine shape in the inner cavity of the refrigerant storage tank, and the end of the air inlet pipe is arranged to pass through the top of the refrigerant storage tank, and the refrigeration pipe in the refrigerant storage tank is arranged in a braided and coiled state with the air inlet pipe.

[0012] Optionally, the air-cooled tank is in the shape of an isosceles trapezoid with a wide end facing the isolation sleeve, and the low-temperature air delivered enters through the narrow end of the air-cooled tank, a plurality of shunt plates are arranged in a fan shape on the variable-diameter cavity part of the air-cooled tank, the air-cooled tank separates the delivered air into a plurality of channels, the shunt plates are provided with energy storage protrusions, the ends of the shunt plates are connected by a connecting plate to pass out of the air-cooled tank and are fixedly connected with horizontally arranged upper and lower associated fins, and a space is left between the flared end of the air-cooled tank and the inner walls of the two cooling clamps, and when the low-temperature air in the air-cooled tank is ejected, the air in the space region is synchronously passed through the associated fins and flows into the circulation pipe region.

[0013] Optionally, the upper end of the liquid-cooled coil is connected in communication with the liquid-cooled piston cylinder through a lifting pipe, and the lower end of the liquid-cooled coil is connected to return to the refrigerant storage tank, and the cooling liquid in the cooling liquid flow path of the isolation sleeve flows in from the top and out from the bottom.

[0014] Optionally, a spiral inner guide plate is arranged along the bottom of the liquid-cooled coil in the inner cavity of the isolation sleeve, and the inner guide plate and the isolation sleeve are both high-thermal-conductivity materials.

[0015] The cooling method of the cooling device for producing dilute nitric acid comprises the following steps:

[0016] S1. Waste heat recovery and refrigeration, using waste heat to drive an absorption refrigeration module to recover the tail gas waste heat generated by the oxidation furnace, capturing the heat in the tail gas through a waste heat recovery unit, and transmitting the heat to an ammonia water absorption refrigeration machine through a heat pipe heat exchanger, the ammonia water absorption refrigeration machine uses the captured heat to produce low-temperature cooling liquid, and the low-temperature cooling liquid is delivered to the refrigerant storage tank through a refrigeration pipe for storage;

[0017] S2. Start the motor in the driving module to drive the driving rod to rotate, the driving rod drives the liquid-cooled piston cylinder and the air-cooled piston cylinder through the piston rod respectively, the liquid-cooled piston cylinder unidirectionally pumps the cooling liquid in the refrigerant storage tank to the liquid-cooled coil to cool the circulation pipe in the isolation sleeve, and the flow path of the cooling liquid in the liquid-cooled coil is from the top to the bottom, which ensures effective heat exchange, at the same time, the air-cooled piston cylinder unidirectionally delivers external air to the air-cooled tank through the air pipe for air cooling, and the low-temperature air is uniformly ejected to the area between the two cooling clamps through the guidance and enhancement of the shunt plate and the associated fin in the air-cooled tank, and further cools the circulation pipe;

[0018] S3. When the driving rod rotates, the worm segment drives the conversion disc to rotate, the conversion disc drives the rocker arm and the swing gear disc to swing and rotate through the shaft pin and the movable bar hole, the swing gear disc is engaged with the ring gear on the end ring at the lower end, the cooling clamp plate is driven to reciprocatingly rotate and swing 0-60 degrees with the circulating pipe as the rotating shaft, and the cooling effect is enhanced;

[0019] S4. The circulating pipe is driven to circulate on the absorption tower through the circulating pump, the lifting section is a spiral structure, is located at the middle position of the two cooling clamp plates, the heat medium in the circulating pipe is cooled under the double cooling actions of the liquid cooling coil and the low-temperature air, and meanwhile, the middle part of the cooling clamp plate is an outwardly convex arc structure, a gap is formed between the cooling clamp plate and the circulating pipe coiled on the isolation sleeve for the air to pass through, and heat exchange is further promoted.

[0020] S5. After the cooling liquid is cooled in the liquid cooling coil, the cooling liquid is returned to the refrigerant energy storage box for the next cycle, the external air sucked into the air cooling piston cylinder is further cooled in the refrigerant energy storage box through the serpentine air inlet pipe and the woven winding area of the refrigeration pipe, and then is delivered to the air cooling box.

[0021] S6. The brush on the driving rod rotates with the driving rod, not only drives the cooling liquid to mix, but also brushes the surface of the refrigeration pipe below and the air pipe connected with the air cooling piston cylinder, so that blockage and dirt are prevented.

[0022] Compared with the prior art, the cooling device for dilute nitric acid production and the cooling method have the following beneficial effects:

[0023] 1. The waste heat drives the absorption refrigeration module, realizes efficient recovery and utilization of tail gas waste heat, and achieves the effect of energy saving and emission reduction.

[0024] 2. The air-liquid cold integrated system realizes efficient cooling of the heat medium, improves the production efficiency, and combines the air cooling and liquid cooling two cooling modes, the heat medium in the circulating pipe is cooled for the first time through the liquid cooling coil, and then the circulating pipe is cooled for the second time by the low-temperature air in the air cooling box from one side, so that the contact area and heat exchange efficiency between the heat medium and the cooling medium are greatly increased, the heat medium in the absorption tower is quickly cooled, and the overall efficiency of the dilute nitric acid production is improved.

[0025] 3、Through the driving module, the reciprocating rotary swing of the cooling clamp plate is realized, the purpose of enhancing the cooling effect and the uniformity of heat exchange is achieved, the motor in the driving module drives the rotation of the driving rod, and a series of transmission mechanisms are used to convert the rotary motion into the reciprocating rotary swing of the cooling clamp plate. This design not only increases the relative movement between the cooling clamp plate and the circulating pipe, improves the uniformity of heat exchange, but also further enhances the cooling effect by changing the angle and position of the cooling clamp plate, so that the heat medium can be more fully exchanged with the cooling medium. During the reciprocating rotary swing of the cooling clamp plate, the cooling air flow can completely wrap the entire circulating pipe, avoiding dead angles and improving cooling efficiency. In this process, the comb teeth can clean the surface of the circulating pipe, avoiding wall hanging and dirt affecting the cooling effect. At the same time, the comb teeth can also uniformly disperse the cooling air flow, ensuring that the air flow blows uniformly from one side to the circulating pipe, so that the dilute nitric acid solution in the circulating pipe can be cooled at the same temperature during the upward conveying process, realizing continuous cooling in stages, and ensuring that the reflux temperature at the top is always stable. Compared with the existing vertical blowing cooling method from the cavity of the spiral circulating pipe, the cooling efficiency is higher, and the reflux temperature control is more accurate.

[0026] 4、Through the brush structure, the surface of the refrigeration pipe and the air pipe is brushed, the effects of preventing blockage and dirt accumulation and improving the cold and heat exchange efficiency are achieved. The brush structure distributed in a ring shape on the driving rod continuously brushes the surface of the refrigeration pipe and the air pipe below during the rotation of the driving rod. This design effectively prevents the attachment and blockage of dirt on the surface of the pipe, ensures the smoothness of the cold and heat exchange channel, thereby improving the cold and heat exchange efficiency and prolonging the service life of the equipment.

[0027] 5、Through the serpentine coiled air inlet pipe and the woven winding structure of the refrigeration pipe, the pre-cooling of the suction air is realized, the effects of improving the air cooling efficiency and reducing the energy consumption are achieved. The serpentine coiled air inlet pipe and the woven winding structure of the refrigeration pipe in the refrigerant energy storage tank make the external air undergo pre-cooling treatment before entering the air cooling tank. This design not only improves the cooling efficiency of the air, but also provides a lower temperature air source for the subsequent air cooling process, thereby reducing the energy consumption of the entire cooling system.

[0028] Other advantages, objects, and features of the present application will be apparent to those skilled in the art in view of the following detailed description and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is the first axial perspective structure schematic diagram of the present application;

[0030] Figure 2 Second axis view schematic diagram of the structure of the application;

[0031] Figure 3 First axis view schematic diagram of the structure of the refrigerant energy storage tank, air cooling tank and cooling clamp plate part of the application;

[0032] Figure 4 Second axis view schematic diagram of the structure of the refrigerant energy storage tank, air cooling tank and cooling clamp plate part of the application;

[0033] Figure 5 Schematic diagram of the structure of the outer cooling clamp plate moving out of the axis view of the application;

[0034] Figure 6 Schematic diagram of the structure of the air cooling tank shell half cut-off state axis view of the application;

[0035] Figure 7 Schematic diagram of the structure of the Figure 6 A enlarged part of the structure of the application;

[0036] Figure 8 Schematic diagram of the structure of the circulation pipe and isolation sleeve pipe cut-off state axis view of the application;

[0037] Figure 9 Schematic diagram of the structure of the driving module and refrigerant energy storage tank part axis view of the application.

[0038] Figure 10 Schematic diagram of the structure of the waste heat driven absorption refrigeration module of the application.

[0039] In the figure:

[0040] 1, waste heat driven absorption refrigeration module; 101, waste heat recovery unit; 102, ammonia water absorption refrigeration machine; 103, heat pipe heat exchanger;

[0041] 2, absorption tower; 201, circulation pipe; 202, hanging rod; 2021, stop ring;

[0042] 3, refrigerant energy storage tank; 301, refrigeration pipe;

[0043] 4, circulating pump;

[0044] 5, driving module; 501, motor; 502, driving rod; 5021, worm section; 5022, piston rod; 5023, brush; 503, liquid-cooled piston cylinder; 504, air-cooled piston cylinder; 505, swing gear; 506, swing arm; 5061, movable bar hole; 507, conversion disc; 5071, worm disc; 5072, shaft pin;

[0045] 6, air cooling tank; 601, flow dividing plate; 6011, energy storage protrusion; 602, associated fin;

[0046] 7. Liquid cooling coil; 701. Lifting pipe;

[0047] 8. Cooling clamp plate; 801. End ring; 8011. Ring tooth; 802. Hanging sleeve; 8021. Movable hole; 803. Comb tooth;

[0048] 9. Isolation sleeve; 901. Inner guide piece. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0050] Please refer to Figures 1-10 The present application 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, the waste heat driven absorption refrigeration module 1 recovers tail gas waste heat from an oxidation furnace to produce refrigeration, and the cold energy is delivered to the refrigerant energy storage tank 3.

[0051] A hanging rod 202 is vertically arranged on the tower wall of the absorption tower 2, a group of stop rings 2021 is arranged at the upper and lower ends of the hanging rod 202 respectively, a hanging sleeve 802 is fixedly arranged at the upper and lower ends of the side wall opposite to the hanging rod 202 of the cooling clamp plate 8 respectively, an arc-shaped movable hole 8021 is formed in the hanging sleeve 802, and the hanging rod 202 passes through the movable hole 8021 and is stopped by the stop rings 2021;

[0052] The air-liquid cooling integrated system comprises a driving module 5, an air cooling tank 6, a liquid cooling coil 7, a cooling clamp plate 8 and an isolation sleeve 9. The cooling clamp plate 8 has two, is oppositely distributed, and is fixedly connected as an integral structure at the upper and lower ends by an end ring 801. The cooling clamp plate 8 is vertically rotatably hung on the outer wall of the absorption tower 2, and the air cooling tank 6 is fixedly installed at one end between the two cooling clamp plates 8. The circulating pipe 201 on the absorption tower 2 is circularly driven by the circulating pump 4 from bottom to top, the lifting section of the circulating pipe 201 is a spiral structure, is located at the middle position of the two cooling clamp plates 8, and the isolation sleeve 9 is vertically clamped in the inner cavity of the spiral section of the circulating pipe 201. The liquid cooling coil 7 is spirally arranged in the isolation sleeve 9. The driving module 5 delivers the cooling liquid in the refrigerant energy storage tank 3 to the liquid cooling coil 7 to cool and circulate the circulating pipe 201. The driving module 5 sucks external air and delivers it to the air cooling tank 6 through the inner cavity of the refrigerant energy storage tank 3 to be air-cooled, and simultaneously drives the cooling clamp plate 8 to reciprocally rotate and swing around the circulating pipe 201 as the rotation axis.

[0053] The waste heat driven absorption refrigeration module 1 comprises a waste heat recovery unit 101 directly connected with the oxidation furnace tail gas outlet flange, an ammonia water absorption refrigeration machine 102 and a heat pipe heat exchanger 103. The waste heat recovery unit 101 is connected with the ammonia water absorption refrigeration machine 102 through the heat pipe heat exchanger 103. The heat pipe heat exchanger 103 transmits the absorbed heat to the ammonia water absorption refrigeration machine 102. The ammonia water absorption refrigeration machine 102 is provided with a refrigeration pipe 301 for conducting low temperature between the ammonia water absorption refrigeration machine 102 and the refrigerant storage tank 3. The refrigeration pipe 301 penetrates the inner cavity of the refrigerant storage tank 3. The waste heat recovery unit 101 is directly connected with the oxidation furnace tail gas outlet flange, so as to capture the heat in the tail gas. The heat pipe heat exchanger 103 connects the waste heat recovery unit 101 and the ammonia water absorption refrigeration machine 102, transmits the absorbed heat to the ammonia water absorption refrigeration machine 102, and the ammonia water absorption refrigeration machine 102 uses the captured heat to refrigerate, generates low-temperature cooling liquid, and the refrigeration pipe 301 connects the ammonia water absorption refrigeration machine 102 and the refrigerant storage tank 3, conducts low temperature, and penetrates the inner cavity of the refrigerant storage tank 3, so as to transport the low-temperature cooling liquid to the refrigerant storage tank 3 for storage.

[0054] 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 swing gear 505, a rocker arm 506 and a conversion disc 507. The motor 501 drives the driving rod 502 to rotate. One end of the driving rod 502 penetrates the refrigerant storage tank 3 and extends out. The driving rod 502 is also rotationally connected with 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 unidirectionally pumps the cooling liquid in the refrigerant storage tank 3 to the liquid-cooled coil 7 under the action of the piston rod 5022. The air-cooled piston cylinder 504 unidirectionally transports external air to the air-cooled tank 6 through the air pipe penetrating the refrigerant storage tank 3. The driving rod 502 in the refrigerant storage tank 3 is also annularly distributed with uniformly spaced brushes 5023. The brushes 5023 are immersed in the cooling liquid. The brushes 5023 rotate with the driving rod 502 to mix the cooling liquid and clean the refrigeration pipe 301 below and the air pipe surface of the air-cooled piston cylinder 504, so as to prevent dirt from adhering to the surface of the pipeline and affecting the heat exchange, improve the refrigeration efficiency and reduce the maintenance frequency.

[0055] The swing gear disc 505 is a semicircular gear disc structure, one end of the swing gear disc 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 gear 8011 which is engaged with the swing gear disc 505, the other end of the swing gear disc 505 is fixedly connected with the swing arm 506, the swing arm 506 is vertically provided with a movable strip hole 5061 at the part close to the end, the lower part of the swing arm 506 is the conversion disc 507, the upper end of the conversion disc 507 is vertically provided with a shaft pin 5072 at the position close to the edge, the shaft pin 5072 passes through the movable strip hole 5061, the lower end of the rotating shaft of the conversion disc 507 is fixedly connected with the volute 5071, the corresponding part of the driving rod 502 to the volute 5071 is the engaged worm segment 5021, the driving rod 502 rotates to drive the conversion disc 507 to rotate, the conversion disc 507 drives the swing gear disc 505 to swing and rotate, the ring gear 8011 drives the cooling clamp plate 8 to rotate by 0-60 degrees, and the cooling effect is enhanced.

[0056] The middle part of each of the two cooling clamp plates 8 is an arc-shaped structure which is outwardly convex, and two rows of comb teeth 803 are vertically arranged on the inner wall of the arc-shaped part of the cooling clamp plate 8, the circulating pipe 201 which is coiled on the isolation sleeve 9 and the inner wall of the cooling clamp plate 8 are left with a gap for air to pass through, the end of the comb tooth 803 is in contact with the circulating pipe 201, the low-temperature air from the air cooling box 6 flows along the interlayer gap, wraps the circulating pipe 201 and passes through, and the cooling clamp plate 8 rotates and swings back and forth with the swing gear disc 505, so that the cooling air flow can completely wrap the entire circulating pipe 201, avoiding the occurrence of dead angles and improving the cooling efficiency, and in this process, the comb tooth 803 can clean the surface of the circulating pipe 201, avoiding the occurrence of wall hanging and dirt affecting the cooling effect, and the comb tooth 803 can also uniformly disperse the cooling air flow, ensuring that the air flow blowing from one side to the circulating pipe 201 is uniform, so that the dilute nitric acid solution in the circulating pipe 201 can be cooled at the same temperature in the whole section during the upward conveying process, realizing continuous cooling in steps and ensuring that the reflux temperature at the top is always stable.

[0057] The air inlet pipe connected with the air cooling piston cylinder 504 is in a serpentine coiled state in the inner cavity of the refrigerant energy storage tank 3, the end of the air inlet pipe passes out from the top of the refrigerant energy storage tank 3, and the refrigeration pipe 301 in the refrigerant energy storage tank 3 is in a woven and wound state with the air inlet pipe, which helps to improve the refrigeration efficiency of the inhaled air and improve the exchange efficiency.

[0058] The air cooling tank 6 is in the shape of an isosceles trapezoid with a wide end facing the isolation sleeve 9, the low-temperature air delivered enters through the narrow end of the air cooling tank 6, a plurality of shunt plates 601 are distributed in a fan shape on the variable-diameter cavity part of the air cooling tank 6, the air cooling tank 6 separates the delivered air into a plurality of channels, the shunt plates 601 are provided with energy storage protrusions 6011, the ends of the shunt plates 601 are connected by a connecting plate to the outside of the air cooling tank 6 and are fixedly connected with horizontally placed associated fins 602 which are uniformly spaced in upper and lower positions, a space is left between the flared end of the air cooling tank 6 and the inner walls of the two cooling clamps 8, when the low-temperature air in the air cooling tank 6 is ejected, the air in the space region is synchronously passed through the associated fins 602 and flows into the circulating pipe 201 region, thereby achieving air cooling of the circulating pipe 201.

[0059] The upper end of the liquid cooling coil 7 is connected to the liquid cooling piston cylinder 503 through a lifting pipe 701, and the lower end of the liquid cooling coil 7 is connected back to the refrigerant energy storage tank 3, and the cooling liquid in the isolation sleeve 9 flows in from the top and out from the bottom, thereby ensuring effective heat exchange.

[0060] The inner guide plate 901 is provided in the inner cavity of the isolation sleeve 9 and is helical along the bottom of the liquid cooling coil 7, and the inner guide plate 901 and the isolation sleeve 9 are both high-thermal-conductivity materials, which helps to improve the heat exchange efficiency.

[0061] The cooling method of the cooling device for producing dilute nitric acid comprises the following steps:

[0062] S1. Waste heat recovery and refrigeration, the exhaust gas waste heat produced by the oxidation furnace is recovered by using a waste heat driven absorption refrigeration module 1, the heat in the exhaust gas is captured by a waste heat recovery unit 101, and the heat is transmitted to an ammonia water absorption refrigeration machine 102 through a heat pipe heat exchanger 103, the ammonia water absorption refrigeration machine 102 performs refrigeration by using the captured heat, generates low-temperature cooling liquid, and delivers the low-temperature cooling liquid to the refrigerant energy storage tank 3 through a refrigeration pipe 301 for storage;

[0063] S2. Start the motor 501 in the driving module 5 to drive the driving rod 502 to rotate, the driving rod 502 drives the liquid cooling piston cylinder 503 and the air cooling piston cylinder 504 through the piston rod 5022, the liquid cooling piston cylinder 503 unidirectionally pumps the cooling liquid in the refrigerant energy storage tank 3 to the liquid cooling coil 7 to cool the circulating pipe 201 in the isolation sleeve 9, the flow path of the cooling liquid in the liquid cooling coil 7 is from the top to the bottom, thereby ensuring effective heat exchange, at the same time, the air cooling piston cylinder 504 unidirectionally delivers external air to the air cooling tank 6 through an air pipe for air cooling, the low-temperature air in the air cooling tank 6 is uniformly ejected to the region between the two cooling clamps 8 through the guidance and enhancement of the shunt plates 601 and the associated fins 602, thereby further cooling the circulating pipe 201;

[0064] S3. When the driving rod 502 rotates, the worm segment 5021 drives the conversion disc 507 to rotate. The conversion disc 507 drives the rocker arm 506 and the swing gear disc 505 to swing and rotate through the shaft pin 5072 and the movable bar hole 5061. The swing gear disc 505 is engaged with the ring gear 8011 on the end ring 801 at the lower end, driving the cooling clamp plate 8 to rotate reciprocally by 0-60 degrees with the circulation pipe 201 as the rotation axis, enhancing the cooling effect.

[0065] S4. The circulation pipe 201 is driven to circulate on the absorption tower 2 by the circulation pump 4. Its lifting segment is a spiral structure located at the middle position of the two cooling clamp plates 8. The heat medium in the circulation pipe 201 is cooled under 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 plate 8 is an outwardly convex arc structure, leaving a gap between the circulation pipe 201 coiled on the isolation sleeve 9 for air to pass through, further promoting heat exchange.

[0066] S5. After the cooling liquid completes the cooling task in the liquid cooling coil 7, it flows back to the refrigerant energy storage tank 3, preparing for the next cycle. The external air sucked into the air-cooled piston cylinder 504 is further cooled in the coiled air inlet pipe and the woven winding area of the refrigeration pipe 301 in the inner cavity of the refrigerant energy storage tank 3, and then delivered to the air-cooled tank 6.

[0067] S6. The brush 5023 on the driving rod 502 rotates with the driving rod 502, not only mixing the cooling liquid, but also cleaning the surface of the refrigeration pipe 301 below and the air pipe connected to the air-cooled piston cylinder 504, preventing blockage and dirt accumulation.

[0068] Working principle: The core of the device is the waste heat driven absorption refrigeration module 1, which is directly connected to the oxidation furnace tail gas outlet flange through the waste heat recovery unit 101, effectively capturing the heat contained in the tail gas. These heat is then efficiently transmitted to the ammonia water absorption refrigeration machine 102 by the heat pipe heat exchanger 103. Inside the ammonia water absorption refrigeration machine 102, the captured heat drives the refrigeration cycle to produce low-temperature cooling liquid. These low-temperature cooling liquid is delivered to the refrigerant energy storage tank 3 for storage for subsequent cooling process.

[0069] The refrigerant energy storage tank 3 not only serves as a storage container for the cooling liquid, but also further improves the cooling efficiency through its internal structure. Inside the tank, the serpentine coiled air inlet pipe is intertwined with the refrigeration pipe 301, forming a unique cooling channel. When external air is sucked into the air-cooled piston cylinder 504 and delivered to the refrigerant energy storage tank 3, the air passes through this cooling channel and is further cooled by the low-temperature cooling liquid and the refrigeration pipe 301. This design not only improves the cooling efficiency of the air, but also provides a lower-temperature air source for the subsequent air-cooling process.

[0070] The air-liquid cooling integrated system is the key to realize the high efficient cooling of the heat medium. The system includes air cooling box 6, liquid cooling coil 7, cooling clamp plate 8 and isolation sleeve 9 and other components. The cooling clamp plate 8 is vertically hung on the outer wall of the absorption tower 2, and the interlayer space formed in the interior provides a channel for air flow. The circulating pipe 201, as the transmission pipeline of the heat medium, adopts a spiral structure in the lifting section and is located in the middle of the two cooling clamp plates 8. This design not only increases the contact area between the heat medium and the cooling medium, but also improves the heat exchange efficiency.

[0071] The liquid cooling coil 7 is spirally arranged inside the isolation sleeve 9, and the cooling liquid is provided by the refrigerant energy storage tank 3. When the cooling liquid flows in the liquid cooling coil 7, it will absorb the heat of the heat medium in the circulating pipe 201, realizing the first cooling. At the same time, the air cooled by the refrigerant energy storage tank 3 is transported to the air cooling box 6 by the air cooling piston cylinder 504. Inside the air cooling box 6, the air is uniformly sprayed into the area between the two cooling clamp plates 8 through the guidance and enhancement of the flow distribution plate 601 and the associated fin 602, and the circulating pipe 201 is subjected to the second cooling. This air-liquid combined cooling method ensures the high efficient cooling of the heat medium.

[0072] In addition, the design of the driving module 5 is also quite ingenious. The motor 501 drives the driving rod 502 to rotate, and then drives the liquid cooling piston cylinder 503 and the air cooling piston cylinder 504 to realize the transportation of the cooling liquid and the suction and discharge of the air, respectively. At the same time, the worm segment 5021 on the driving rod 502 is engaged with the worm disc 5071 on the conversion disc 507, realizing the conversion of the rotation of the driving rod 502 to the swing rotation of the swing gear 505. The swing gear 505 is engaged with the ring teeth 8011 on the end ring 801 at the lower end of the cooling clamp plate 8, driving the cooling clamp plate 8 to reciprocatingly rotate and swing around the circulating pipe 201 as the rotation axis by 0-60 degrees. This design not only enhances the cooling effect, but also improves the uniformity of heat exchange.

[0073] It is worth noting that the driving rod 502 also has uniformly spaced brushes 5023 arranged in a ring. These brushes 5023 rotate with the driving rod 502, not only driving the cooling liquid mixing, but also cleaning the surface of the refrigeration pipe 301 below and the air pipe connected with the air cooling piston cylinder 504. This design effectively prevents the attachment of dirt on the surface of the pipeline, ensures the efficient heat exchange, and also reduces the maintenance frequency.

[0074] It is apparent for a person skilled in the art that the present application is not limited to the details of the above described exemplary embodiments, but that it can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. Therefore, the embodiments should be considered in all respects as illustrative and not restrictive, the scope of the application being defined by the appended claims rather than the above description, and all changes coming within the meaning and equivalency range of the claims are intended to be embraced therein.

Claims

1. A cooling device for dilute nitric acid production, characterized by, Include: The waste heat driven absorption refrigeration module (1), the refrigerant energy storage tank (3) and the air-liquid cold integrated system, the waste heat driven absorption refrigeration module (1) recycles the tail gas waste heat of the oxidation furnace and produces refrigeration, and the cold energy is transported to the refrigerant energy storage tank (3); The air-liquid cold integrated system includes a driving module (5), an air cooling tank (6), a liquid cooling coil (7), two cooling clamps (8) and an isolation sleeve (9), the two cooling clamps (8) are oppositely distributed and are fixedly connected to an integral structure through end rings (801) at upper and lower ends, the cooling clamps (8) are vertically hung on the outer wall of the absorption tower (2), and the air cooling tank (6) is fixedly installed at one end between the two cooling clamps (8); The circulating pipe (201) on the absorption tower (2) is circularly driven by a circulating pump (4) from bottom to top, the lifting section of the circulating pipe (201) is a spiral structure and is located at the middle position of the two cooling clamps (8), the isolation sleeve (9) is vertically clamped in the spiral section of the circulating pipe (201), and the liquid cooling coil (7) is spirally arranged in the isolation sleeve (9); The driving module (5) delivers the coolant in the coolant storage tank (3) to the liquid cooling coil (7) to cool and circulate the circulating pipe (201), the driving module (5) sucks and delivers the external air to the air cooling tank (6) through the inner cavity of the coolant storage tank (3) to air cool, and synchronously drives the cooling clamp plate (8) to reciprocatingly rotate and swing around the circulating pipe (201) as the rotating shaft; the waste heat driven absorption refrigeration module (1) comprises a waste heat recovery unit (101) directly connected with the flange at the outlet of the oxidation furnace tail gas, an ammonia water absorption refrigeration machine (102) and a heat pipe heat exchanger (103), the waste heat recovery unit (101) is connected with the ammonia water absorption refrigeration machine (102) through the heat pipe heat exchanger (103), the heat pipe heat exchanger (103) transmits the absorbed heat to the ammonia water absorption refrigeration machine (102), the ammonia water absorption refrigeration machine (102) is provided with a refrigeration pipe (301) for conducting low temperature between the ammonia water absorption refrigeration machine (102) and the coolant storage tank (3), and the refrigeration pipe (301) penetrates through the inner cavity of the coolant storage tank (3); the driving module (5) comprises a motor (501), a driving rod (502), a liquid cooling piston cylinder (503), an air cooling piston cylinder (504), a swing gear (505), a rocker arm (506) and a conversion disc (507), the motor (501) drives the driving rod (502) to rotate, one end of the driving rod (502) penetrates through the coolant storage tank (3) and penetrates out, and the driving rod (502) is further rotationally connected with two piston rods (5022), the two piston rods (5022) correspond to the liquid cooling piston cylinder (503) and the air cooling piston cylinder (504) respectively, the liquid cooling piston cylinder (503) unidirectionally delivers the coolant in the coolant storage tank (3) to the liquid cooling coil (7) under the action of the piston rod (5022), the air cooling piston cylinder (504) unidirectionally delivers the external air to the air cooling tank (6) through the air pipe penetrating through the coolant storage tank (3), and the driving rod (502) in the coolant storage tank (3) is further annularly distributed with uniformly spaced brushes (5023), the brushes (5023) are immersed in the coolant, and the brushes (5023) rotate with the driving rod (502) to drive the coolant to mix and simultaneously clean the refrigeration pipe (301) below and the air pipe surface of the air cooling piston cylinder (504). The swing gear plate (505) is a semicircular gear plate structure, one end of the swing gear plate (505) corresponds to an end ring (801) at the lower end, an arc-shaped ring gear (8011) is arranged on the end ring (801) at the lower end and is engaged with the swing gear plate (505), the other end of the swing gear plate (505) is fixedly connected with a swing arm (506), a movable strip hole (5061) is vertically and penetratingly arranged on a part of the swing arm (506) close to the end, a conversion disc (507) is below the swing arm (506), a shaft pin (5072) is vertically arranged on the upper end face of the conversion disc (507) close to the edge, the shaft pin (5072) passes through the movable strip hole (5061), a volute (5071) is fixedly connected to the lower end of the rotating shaft of the conversion disc (507), a worm segment (5021) corresponding to the volute (5071) is arranged on the driving rod (502), the driving rod (502) is rotated to drive the conversion disc (507) to rotate, the conversion disc (507) drives the swing gear plate (505) to swing and rotate, and the ring gear (8011) drives the cooling clamp plate (8) to rotate by 0-60 degrees.

2. The cooling device for producing dilute nitric acid according to claim 1, characterized in that: A hanging rod (202) is vertically arranged on the tower wall of the absorption tower (2), a group of blocking rings (2021) are arranged on the upper and lower ends of the hanging rod (202), respectively, hanging sleeves (802) are fixedly arranged on the side walls opposite to the hanging rod (202) of the cooling clamp plate (8) and are located at the upper and lower ends, respectively, arc-shaped movable holes (8021) are arranged on the hanging sleeves (802), the hanging rod (202) passes through the movable holes (8021) and is stopped by the blocking rings (2021).

3. The cooling device for producing dilute nitric acid according to claim 1, characterized in that: The middle parts of the two cooling clamp plates (8) are arc-shaped structures protruding outward, and two rows of comb teeth (803) are vertically arranged on the inner walls of the arc-shaped parts of the cooling clamp plates (8), a gap for air passing through is left between the circulating pipes (201) coiled on the isolation sleeve (9) and the inner walls of the cooling clamp plates (8), the ends of the comb teeth (803) are in contact with the circulating pipes (201), and the low-temperature air from the air cooling box (6) flows along the interlayer gap, wraps the circulating pipes (201) and passes through.

4. The cooling device for producing dilute nitric acid according to claim 1, characterized by: The air inlet pipe connected with the air cooling piston cylinder (504) is in a serpentine coiled state in the inner cavity of the refrigerant energy storage tank (3), the end of the air inlet pipe passes out from the top of the refrigerant energy storage tank (3), and the refrigeration pipe (301) in the refrigerant energy storage tank (3) is in a woven and wound state with the air inlet pipe.

5. The cooling device for producing dilute nitric acid according to claim 1, characterized by: The air cooling box (6) is in the shape of an isosceles trapezoid with a wide end facing the isolation sleeve (9), the low-temperature air delivered enters through the narrow end of the air cooling box (6), a plurality of shunt plates (601) are arranged 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 a plurality of channels, the shunt plates (601) are provided with energy storage protrusions (6011), the ends of the shunt plates (601) are connected by a connecting plate to the outside of the air cooling box (6) and are fixedly connected with horizontally placed associated fins (602) which are uniformly spaced in upper and lower positions, a space is left between the flared end of the air cooling box (6) and the inner walls of the two cooling clamps (8), when the low-temperature air in the air cooling box (6) is ejected, the air in the space area is synchronously passed through the associated fins (602) and flows into the circulation pipe (201) area.

6. The cooling device for producing dilute nitric acid according to claim 1, characterized by: The upper end of the liquid cooling coil (7) is connected to the liquid cooling piston cylinder (503) through a lifting pipe (701), the lower end of the liquid cooling coil (7) is connected to the refrigerant storage tank (3) in a backflow manner, and the cooling liquid flowing path of the liquid cooling coil (7) in the isolation sleeve (9) is upward inlet and downward outlet.

7. The cooling device for producing dilute nitric acid according to claim 1, characterized by: The inner guide vane (901) is arranged in a spiral along the bottom of the liquid cooling coil (7) in the inner cavity of the isolation sleeve (9), and the inner guide vane (901) and the isolation sleeve (9) are both high-thermal-conductivity materials.

8. A cooling method for a cooling device for dilute nitric acid production, which is applied to the cooling device for dilute nitric acid production according to any one of claims 1 to 7, characterized by, The method comprises the following steps: S1. Waste heat recovery and refrigeration, the waste heat produced by the oxidation furnace is recovered by using a waste heat driven absorption refrigeration module (1), the heat in the tail gas is captured by a waste heat recovery unit (101), and the heat is transmitted to an ammonia water absorption refrigeration machine (102) by a heat pipe heat exchanger (103), the ammonia water absorption refrigeration machine (102) performs refrigeration by using the captured heat, generates low-temperature cooling liquid, and delivers the low-temperature cooling liquid to the refrigerant storage tank (3) through a refrigeration pipe (301) for storage; S2. The motor (501) in the driving module (5) is started, the driving rod (502) is driven to rotate, the driving rod (502) drives the liquid cooling piston cylinder (503) and the air cooling piston cylinder (504) through the piston rod (5022) respectively, the liquid cooling piston cylinder (503) unidirectionally pumps the cooling liquid in the refrigerant storage tank (3) to the liquid cooling coil (7), and the circulation pipe (201) in the isolation sleeve (9) is cooled, the flow path of the cooling liquid in the liquid cooling coil (7) is upward inlet and downward outlet, effective heat exchange is ensured, at the same time, the air cooling piston cylinder (504) unidirectionally delivers external air to the air cooling box (6) through an air pipe for air cooling, the low-temperature air in the air cooling box (6) is uniformly sprayed to the area between the two cooling clamps (8) under the guidance and enhancement of the shunt plates (601) and the associated fins (602), and the circulation pipe (201) is further cooled. S3. When the driving rod (502) rotates, the worm segment (5021) drives the conversion disc (507) to rotate, the conversion disc (507) drives the rocker arm (506) and the swing gear disc (505) to swing and rotate through the shaft pin (5072) and the movable bar hole (5061), the swing gear disc (505) is engaged with the ring gear (8011) on the end ring (801) at the lower end, driving the cooling clamp plate (8) to rotate reciprocatingly at 0-60 degrees with the circulation pipe (201) as the rotation axis, 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 segment is a spiral structure, located at the middle position of the two cooling clamp plates (8), the heat medium in the circulation pipe (201) is cooled under the double cooling action of the liquid cooling coil (7) and the low-temperature air, at the same time, the middle part of the cooling clamp plate (8) is an outward convex arc structure, leaving a gap for air passing between the circulation pipe (201) coiled on the isolation sleeve pipe (9), further promoting heat exchange; S5. After the cooling liquid completes the cooling task in the liquid cooling coil (7), it flows back to the refrigerant energy storage tank (3) for the next cycle, the external air sucked into 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 woven winding area of the refrigeration pipe (301), and then delivered to the air-cooled tank (6); S6. The brush (5023) on the driving rod (502) rotates with the driving rod (502), not only drives the cooling liquid mixing, but also brushes the surface of the refrigeration pipe (301) below and the air pipe connected with the air-cooled piston cylinder (504), preventing blockage and dirt accumulation.

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