Heat energy recovery system and apparatus based on small-diameter dual-function tubing

Abstract

A heat energy recovery system and an apparatus, based on a small-diameter dual-function tubing, comprising a thermally insulated medium storage tank and multiple heat exchange air blast spaces. Each heat exchange air blast space has provided therein a tube-fin heat exchanger, the diameter of a heat exchange tube (2) in each tube-fin heat exchanger being less than or equal to 4 mm. Each tube-fin heat exchanger is provided with a liquid inlet valve (31) and liquid outlet valve (41). A liquid inlet pump is disposed at an output end of the medium storage tank, and the liquid inlet pump is connected to each liquid inlet valve (31) by means of a branching tube. The heat exchange area / external volume of each tube-fin heat exchanger is greater than or equal to 280 m2 / m3. By means of discarding the serial connection means of conventional fin heat exchangers, when one of the heat exchange tubes (2) is blocked, fluid can flow along the other, unblocked heat exchange tubes (2), enabling the tube-fin heat exchanger to operate normally.

Description

Heat recovery system and device based on small-diameter dual function

[0001] Technical Field

[0002] This invention relates to the field of heat recovery technology, specifically to a heat recovery system and device based on a small-diameter dual-function pipe.

[0003] Background Technology

[0004] In the chemical industry, many compounds are obtained through substitution reactions. Substitution reactions are exothermic, releasing a large amount of heat. To maintain the normal operation of the reactor, the reactor jacket is connected to a circulating cooling system, using a heat transfer medium (such as water) to transfer heat to a cooling tower. After being cooled by the cooling tower, the heat is either reintroduced into the reactor jacket's circulating cooling system or directly discharged. Exothermic reactions cause the high-temperature section of the heat transfer medium to reach 120℃-130℃, while the medium input temperature of the cooling tower is approximately 80℃. Currently, the heat exchange area to heat exchanger volume ratio of cooling towers in the chemical industry is approximately 8.4 m² / m³, resulting in low heat exchange efficiency, large size, and a large footprint.

[0005] In the production of chlorinated polymers, the substitution reaction of chlorine is exothermic, releasing approximately 3500 kJ of heat per kilogram of chlorine. Traditional processes require this heat to be transferred away via hot water or other media, followed by evaporation and heat dissipation through open or closed cooling towers before recycling. The outlet temperature of the circulating water is typically above 80°C. The drying process generally employs fluidized bed drying, which requires a steam heat exchanger, usually a tube-fin type, to heat the air to a specific temperature. Intermittent bed drying typically uses air at approximately 70°C-80°C. Continuous fluidized bed drying generally falls into two categories: flash drying and fluidized bed chamber drying. Flash drying... Drying requires hot air temperatures of approximately 110℃-120℃, while fluidized bed drying requires approximately 65℃-85℃. In response to the national policy of energy conservation and emission reduction, the high-temperature hot water generated by the chlorination reaction can be used in the heat exchanger for drying. However, traditional heat exchangers are DN25 or DN32 tube-fin heat exchangers, which are quite large. If steam heat exchange is used, the heat exchange area can be within approximately 1250m² to meet the drying requirements. But if hot water heat exchange is used, the volume is even larger, which cannot meet the relevant performance requirements of fluidized bed drying, such as high air resistance, insufficient air volume, large footprint, limited installation space, and low equipment reliability.

[0006] As the core device of a heat recovery system, the importance of the tube-fin heat exchanger is self-evident. Its principle is that a fluid carrying heat energy enters the heat exchange tubes through the liquid inlet. Multiple heat exchange tubes are connected end-to-end by bends to form a single liquid flow channel. The fluid inside the heat exchange tubes transfers heat to the fins on the outer wall, while air enters the tube-fin heat exchanger through the air inlet and comes into contact with the fins, thus carrying away the heat from the fin surface and heating the air. The heated air is then stored in a tank for recycling. Because multiple heat exchange tubes are connected end-to-end to form a single liquid flow channel, the residence time of the fluid in the heat exchange tubes is increased, allowing for sufficient heat exchange and improving heat recovery efficiency. However, due to the limitations of a single liquid flow channel, if a section of the liquid flow channel becomes blocked, multiple heat exchange tubes will be unable to receive fluid, causing the entire tube-fin heat exchanger to malfunction and affecting heat recovery. Summary of the Invention

[0007] To overcome the shortcomings of existing technologies, this invention proposes a heat recovery system and device based on a small-diameter dual-function tube. This invention boasts advantages such as high heat exchange efficiency, small footprint, and significant energy savings. It utilizes the heat from chlorination reactions or other exothermic reactions in the subsequent product drying process. The inherent fluidization stage in the production process achieves cooling of the high-temperature medium, while the heat released by the exothermic reaction is used as the production of hot air for fluidized bed drying. This allows the fluidized bed to perform both fluidized drying and cooling functions, greatly reducing energy consumption. Simultaneously, the heat exchange area / volume of the tube-fin heat exchanger is ≥280 m² / m³, increasing the heat exchange area without increasing the heat exchanger volume. Only the existing blower heat exchange space in the fluidized bed needs to be modified with a tube-fin heat exchanger, reducing energy consumption without increasing the footprint or volume.

[0008] The technical solution adopted by this invention to solve its technical problem is as follows: The heat energy recovery system based on small-diameter dual-function as described in this invention includes an insulated medium storage tank, multiple heat exchange blowing spaces, each heat exchange blowing space having its own tube-fin heat exchanger; the diameter of the heat exchange tubes in the tube-fin heat exchanger is ≤4mm; each tube-fin heat exchanger has its own inlet valve and outlet valve, and an inlet pump is installed at the output end of the medium storage tank, the inlet pump being connected to each inlet valve via branch pipes; the heat exchange area / volume of each tube-fin heat exchanger is ≥280m2 / m3; the airflow inlet of each heat exchange blowing space is connected to its own blower, and the air temperature output from the heat exchange blowing space is 65℃-85℃; the medium storage tank has at least one first medium inlet that allows heat transfer medium with a temperature higher than 95℃ to be input into it.

[0009] Preferably, the medium storage tank has at least one second medium inlet that allows heat transfer medium at temperatures below 80°C to be input into it, and the medium output from each outlet valve is input into the second medium inlet of the medium storage tank via a return pipe and a return valve; or, the medium output from each outlet valve is input into the second medium inlet of the medium storage tank via a return pipe and a return valve through a cooling tower.

[0010] Preferably, each tube-fin heat exchanger has a set of water heat exchangers; or each tube-fin heat exchanger has a set of water heat exchangers and a set of steam heat exchangers, with the water heat exchangers and steam heat exchangers connected in parallel.

[0011] Preferably, the heat exchange area of ​​each group of tube-fin heat exchangers is ≥1250m²; the diameter of a single heat exchange tube / the heat exchange area of ​​a single fin is ≥1mm / 50m² (3mm / 150m²).

[0012] Preferably, the heat recovery system applied to a closed-loop cooling tower includes at least one set of tube-fin heat exchangers, each with a heat exchange area / volume ≥ 280 m² / m³. Applying the heat recovery system of this invention to a closed-loop cooling tower can reduce the temperature of the heat transfer medium from around 80°C to 30°C or below, achieving higher heat exchange efficiency for the same volume compared to traditional closed-loop cooling towers (typically with a heat exchange area / volume of 8.4 m² / m³).

[0013] Preferably, the heat recovery system applied to the exothermic chemical reaction includes at least one set of tube-fin heat exchangers, and the heat exchange area / external volume of each tube-fin heat exchanger is ≥280m2 / m3.

[0014] Preferably, in the application of the heat recovery system in the production of chlorinated polymers, the heat recovery device in the heat recovery system includes at least one set of tube-fin heat exchangers, each of which has a heat exchange area / volume ≥ 280 m² / m³. Applying the heat recovery system of this invention to the production of chlorinated polymers can reduce the temperature of the heat transfer medium in the high-temperature section of the chlorination reaction vessel from 120°C-130°C to 65°C-85°C.

[0015] Preferably, a tube-fin heat exchanger is installed at the air inlet of the fluidized bed, and the air enters the fluidized bed chamber after passing through the tube-fin heat exchanger. The ambient air is heated to 65℃-85℃ after heat exchange in the tube-fin heat exchanger and then introduced into the fluidized bed chamber / bed layer.

[0016] Preferably, the heat transfer medium of the tube-fin heat exchanger is the heat transfer medium after the reaction jacket absorbs the reaction heat. The heat transfer medium channel outlet of the reaction vessel and the medium inlet of the tube-fin heat exchanger are connected by a first pipeline. A first pump is installed on the first pipeline, and the first pump causes the heat transfer medium to flow from the reaction vessel jacket to the tube-fin heat exchanger.

[0017] Preferably, each chamber of the fluidized bed is equipped with its own tube-fin heat exchanger at its inlet.

[0018] Preferably, the heat transfer medium output from the tube-fin heat exchanger is fed into the reactor jacket via a second pipe; or, the heat transfer medium output from the tube-fin heat exchanger is fed into a closed cooling tower via a third pipe.

[0019] Preferably, in the application of the above-mentioned heat recovery system in the production of chlorinated polymers, the high-temperature medium inlet of the medium storage tank is connected to the medium outlet of the chlorination reactor jacket, and the heat transfer medium with a temperature higher than 95°C inside the reactor jacket is input into the medium storage tank; the air output from the heat exchange blower space is input into the fluidization chamber of the fluidized bed; the heat recovery system serves as the hot air input system for the fluidized bed.

[0020] Preferably, the substitution reaction of chlorine is exothermic, releasing approximately 3500 kJ of heat per kilogram of chlorine reacted. This heat is transferred away through the heat transfer medium in the reactor jacket to maintain the reactor temperature and ensure the normal occurrence of the substitution reaction; the high-temperature section of this medium can reach 120℃-130℃. The outlet water temperature of the reactor jacket is approximately 80℃.

[0021] Preferably, the drying process for chlorinated polymers generally employs fluidized bed drying, requiring a steam heat exchanger to heat the air to a specific temperature. Intermittent fluidized bed drying typically uses air at approximately 70℃-80℃; continuous fluidized bed drying generally involves flash drying and fluidized bed chamber drying. Flash drying requires hot air temperatures of approximately 110℃-120℃, while fluidized bed chamber drying requires hot air temperatures of approximately 65℃-85℃. In traditional processes, all heat transfer media in the reactor are first cooled to approximately 32℃ in a cooling tower before being used as heat transfer media in the reactor for cooling.

[0022] Preferably, in this invention, the high-temperature medium in the reactor jacket is removed, and its heat energy is used by a heat recovery system to generate hot air for the fluidized bed. This satisfies the hot air drying requirements of the fluidized bed while simultaneously reducing the temperature of the high-temperature medium to 65℃-80℃. At this point, the fluidized bed acts as the first stage of cooling. The medium exiting the fluidized bed can be directly fed into the reactor for high-temperature cooling, or it can be fed into a cooling tower to be cooled to below 32℃ before being fed into the reactor for low-temperature cooling.

[0023] Preferably, the heat exchanger can be installed either after or before the fan.

[0024] This device is based on a small-diameter dual-function heat recovery system, applicable to the aforementioned small-diameter dual-function heat recovery system. The device includes a tube-fin heat exchanger; the tube-fin heat exchanger includes a shell and finned bodies inside the shell; multiple finned bodies are arranged adjacent to each other; the finned bodies are evenly distributed in the left-right direction inside the shell; multiple finned bodies form movable gaps with the front and rear inner walls of the shell; multiple baffles are fixedly connected within the movable gaps; the baffles are in sealing contact with the finned bodies and with the inner wall of the shell; within two movable gaps... The baffles are staggered on the left and right sides; the front side of the shell is connected to the air inlet connector; the rear side of the shell is connected to the air outlet connector; the air inlet connector and the air outlet connector are set far apart from each other on the left and right sides of the shell; multiple heat exchange tubes are arranged through the left and right sides of the shell; the multiple heat exchange tubes are in contact with the fin body; the left side of the shell is fixedly connected to the liquid inlet tank; the lower inner wall of the liquid inlet tank is fixedly connected to the liquid inlet valve; the right side of the shell is fixedly connected to the liquid outlet tank; the lower inner wall of the liquid outlet tank is fixedly connected to the liquid outlet valve; one end of the heat exchange tube is connected to the liquid inlet tank and the other end is connected to the liquid outlet tank.

[0025] Preferably, the inner wall of the liquid inlet tank is movably and sealingly connected to the liquid inlet plate; the upper surface of the liquid inlet plate is fixedly connected to the left rod; a left hole is provided through the upper part of the inner wall of the liquid inlet tank; the upper end of the left rod passes through the left hole and is fixedly connected to the movable plate; a gap is left between the left hole and the outer wall of the left rod; the lower surface of the movable plate is connected to the upper surface of the shell by a tension spring.

[0026] Preferably, the inner wall of the liquid outlet tank is movably and sealingly connected to the liquid outlet plate; the upper surface of the liquid outlet plate is fixedly connected to the right rod; a right hole is provided through the upper part of the inner wall of the liquid outlet tank; the upper end of the right rod passes through the right hole and is fixedly connected to the lower surface of the movable plate; a gap is left between the right hole and the outer wall of the right rod; and a one-way valve is provided at the end of each heat exchange tube, with one end flowing in and the other end flowing out.

[0027] Preferably, the top wall of the housing is provided with a front hole and a rear hole; the front hole is located directly above the front movable gap; the rear hole is located directly above the rear movable gap; the front movable gap is divided into multiple front gaps by a baffle; a front movable block is movably and sealingly connected within the front gap; a front rod is fixedly connected to the upper surface of the front movable block; the upper end of the front rod passes through the front hole and is fixedly connected to the lower surface of the movable plate; the rear movable gap is divided into multiple rear gaps by a baffle; a rear movable block is movably and sealingly connected within the rear gap; a rear rod is fixedly connected to the upper surface of the rear movable block; the upper end of the rear rod passes through the rear hole and is fixedly connected to the lower surface of the movable plate.

[0028] Preferably, multiple partitions are evenly distributed on the inner wall of the shell; the partitions are made of the same material as the fin body; the partitions extend forward to the front gap and backward to the rear gap; the partitions separate two adjacent heat exchange tubes; the vertical thickness of the front movable block and the rear movable block is greater than the distance between adjacent partitions; the lengths of the front rod, rear rod, left rod and right rod are equal.

[0029] Preferably, the upper surfaces of the shell, the inlet tank, and the outlet tank are flush; a protective shell is fixedly connected to the upper surfaces of the shell, the inlet tank, and the outlet tank; the inner wall of the protective shell is movably and sealingly connected to the outer wall of the movable plate; a compensation block is movably and sealingly connected to the upper and lower parts of the movable plate; the compensation block is fixedly connected to the shell; the space between the lower surface of the movable plate and the upper surface of the shell is called a storage cavity; gas in the inlet tank, the outlet tank, and the movable gap can enter the storage cavity for clearance storage.

[0030] The beneficial effects of this invention are as follows:

[0031] 1. This invention has the advantages of high heat exchange efficiency, small footprint, and significant energy savings. It utilizes the heat from chlorination reactions or other exothermic reactions in the subsequent product drying process. The inherent fluidization process in the production process achieves cooling of the high-temperature medium, and the heat released by the exothermic reaction is used as the production of hot air for fluidized drying. This allows the fluidized bed to have both fluidized drying and cooling functions, greatly reducing energy consumption. Simultaneously, the heat exchange area / volume of the tube-fin heat exchanger is ≥280 m² / m³, increasing the heat exchange area without increasing the heat exchanger volume. Only the existing blower heat exchange space in the fluidized bed needs to be modified with a tube-fin heat exchanger, reducing energy consumption without increasing the footprint or volume.

[0032] 2. This invention can completely replace the original steam heat exchanger with a hot water heat exchanger; alternatively, a portion of the original steam heat exchanger can be retained. Hot water is pumped into the tube-fin heat exchanger via a hot water pump. The heat exchanger tube diameter of this invention is ≤4mm, and each small heat exchanger tube is equipped with hydrophobic aluminum fins to increase the heat exchange area. Thus, in the same space, compared to heat exchangers with heat exchanger tube diameters of 25mm or 32mm, the heat exchange area is more than doubled, while the air resistance is ≤300pa, ensuring stable operation of the fluidized bed dryer.

[0033] 3. This invention uses multiple heat exchange tubes connected in parallel, abandoning the series connection method of traditional finned heat exchangers. This allows fluid to flow along the other unblocked heat exchange tubes even if one heat exchange tube is blocked, enabling the tube-fin heat exchanger to operate normally. The inlet plate is movably connected vertically within the inlet tank, and the outlet plate is movably connected within the outlet tank. This allows the number of heat exchangers in the tube-fin heat exchanger to adapt to changes in the amount of incoming fluid. This addresses the issues of insufficient heat exchange tubes affecting heat recovery efficiency and insufficient fluid within the heat exchange tubes affecting heat recovery performance.

[0034] 4. In this invention, the rear movable block and the front movable block are at the same height and move upward synchronously. The distance between adjacent partitions is less than the thickness of the front and rear movable blocks. Thus, through the cooperation of the front and rear movable blocks, the space around the activated heat exchange tubes in the shell is separated from that around the inactive heat exchange tubes. This allows the gas entering the shell to concentrate on exchanging heat with the fins around the activated heat exchange tubes, further ensuring the heat recovery effect. Attached Figure Description

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0036] Figure 1 is a schematic diagram of the original process of the recycling system;

[0037] Figure 2 is a schematic diagram of the current process of the recycling system;

[0038] Figure 3 shows one arrangement of the heat exchange tubes in this invention;

[0039] Figure 4 shows the second arrangement of the heat exchange tubes in this invention;

[0040] Figure 5 is a perspective view of the tube-fin heat exchanger in this invention;

[0041] Figure 6 is a three-dimensional view of Figure 5 from another angle;

[0042] Figure 7 is a perspective view of the tube-fin heat exchanger of the present invention without the protective shell;

[0043] Figure 8 is a perspective view of the inlet tank and outlet tank in this invention;

[0044] Figure 9 is a perspective view of the shell in this invention;

[0045] Figure 10 is a perspective view of the finned body and heat exchange tube in this invention;

[0046] Figure 11 is a top sectional view of Figure 5.

[0047] In the diagram: 1. Shell 1, fin body 11, movable gap 12, front gap 121, rear gap 122, baffle 13, air inlet connector 14, air outlet connector 15, front hole 16, rear hole 17, partition 18, heat exchange tube 2, liquid inlet tank 3, liquid inlet valve 31, liquid inlet plate 32, left rod 33, left hole 34, liquid outlet tank 4, liquid outlet valve 41, liquid outlet plate 42, right rod 43, right hole 44, movable plate 5, tension spring 51, front movable block 52, front rod 53, rear movable block 54, rear rod 55, compensation block 56, storage cavity 57, protective shell 6. Detailed Implementation

[0048] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0049] As shown in Figures 1 to 11, the present invention includes the following embodiments: Example 1

[0050] The heat recovery system based on small-diameter dual-function tubes includes an insulated medium storage tank, multiple heat exchange blowing spaces, and each heat exchange blowing space has its own tube-fin heat exchanger; the diameter of the heat exchange tubes 2 in the tube-fin heat exchanger is ≤4mm; each tube-fin heat exchanger has its own inlet valve 31 and outlet valve 41, and an inlet pump is installed at the output end of the medium storage tank, which is connected to each inlet valve 31 by a branch pipeline; the heat exchange area / volume of each tube-fin heat exchanger is ≥280m2 / m3; the airflow inlet of each heat exchange blowing space is connected to its own blower, and the air temperature output from the heat exchange blowing space is 65℃-85℃; the medium storage tank has at least one first medium inlet that allows heat transfer medium with a temperature higher than 95℃ to be input into it.

[0051] The medium storage tank has at least one second medium inlet that allows heat transfer medium at temperatures below 80°C to be input into it. The medium output from each outlet valve 41 is input into the second medium inlet of the medium storage tank via a return pipe and a return valve; or, the medium output from each outlet valve 41 is input into the second medium inlet of the medium storage tank via a return pipe and a return valve through a cooling tower.

[0052] Each tube-fin heat exchanger has a set of water heat exchangers; or each tube-fin heat exchanger has a set of water heat exchangers and a set of steam heat exchangers, with the water heat exchangers and steam heat exchangers connected in parallel.

[0053] The heat exchange area of ​​each group of tube-fin heat exchangers is ≥1250m²; the heat exchange area of ​​a single heat exchange tube is ≥1mm / 50m² (3mm / 150m²).

[0054] A heat recovery system for closed-circuit cooling towers includes at least one set of tube-fin heat exchangers, each with a heat exchange area / volume ≥ 280 m² / m³. Applying this heat recovery system to a closed-circuit cooling tower can reduce the temperature of the heat transfer medium from around 80°C to 30°C or below, achieving higher heat exchange efficiency for the same volume compared to traditional closed-circuit cooling towers (typically with a heat exchange area / volume of 8.4 m² / m³).

[0055] A heat recovery system for chemical exothermic reactions includes at least one set of tube-fin heat exchangers, each with a heat exchange area / volume ≥ 280 m2 / m3.

[0056] The heat recovery system is applied in the production of chlorinated polymers. The system includes at least one set of tube-fin heat exchangers, each with a heat exchange area / volume ≥ 280 m² / m³. Applying this heat recovery system to the production of chlorinated polymers can reduce the temperature of the heat transfer medium in the high-temperature section of the chlorination reaction vessel from 120°C-130°C to 65°C-85°C.

[0057] A tube-fin heat exchanger is installed at the air inlet of the fluidized bed, and the air enters the fluidized bed chamber after passing through the tube-fin heat exchanger. The ambient air is heated to 65℃-85℃ after heat exchange in the tube-fin heat exchanger and then introduced into the fluidized bed chamber / bed layer.

[0058] The heat transfer medium of the tube-fin heat exchanger is the heat transfer medium after the reaction jacket absorbs the heat of reaction. The heat transfer medium channel outlet of the reaction vessel and the medium inlet of the tube-fin heat exchanger are connected by a first pipe. A first pump is installed on the first pipe, and the first pump causes the heat transfer medium to flow from the reaction vessel jacket to the tube-fin heat exchanger.

[0059] Each chamber of the fluidized bed is equipped with its own tube-fin heat exchanger at its inlet.

[0060] The heat transfer medium output from the tube-fin heat exchanger is fed into the reactor jacket through a second pipe; or, the heat transfer medium output from the tube-fin heat exchanger is fed into a closed cooling tower through a third pipe.

[0061] In the application of the above-mentioned heat recovery system in the production of chlorinated polymers, the high-temperature medium inlet of the medium storage tank is connected to the medium outlet of the chlorination reactor jacket, and the heat transfer medium with a temperature higher than 95°C inside the reactor jacket is input into the medium storage tank; the air output from the heat exchange blower space is input into the fluidization chamber of the fluidized bed; the heat recovery system serves as the hot air input system for the fluidized bed.

[0062] The substitution reaction of chlorine is exothermic, releasing approximately 3500 kJ of heat per kilogram of chlorine gas reacted. This heat is transferred away through the heat transfer medium in the reactor jacket to maintain the reactor temperature and ensure the normal occurrence of the substitution reaction; the high-temperature section of this medium can reach 120℃-130℃. The outlet water temperature of the reactor jacket is approximately 80℃.

[0063] The drying process for chlorinated polymers generally employs fluidized bed drying, requiring a steam heat exchanger to heat the air to a specific temperature. Intermittent fluidized bed drying typically uses air temperatures of approximately 70℃-80℃; continuous fluidized bed drying is generally divided into flash drying and fluidized bed chamber drying. Flash drying requires hot air temperatures of approximately 110℃-120℃, while fluidized bed chamber drying requires hot air temperatures of approximately 65℃-85℃. In traditional processes, all heat transfer media in the reactor are first cooled to approximately 32℃ in a cooling tower before being used as heat transfer media to cool the reactor.

[0064] This invention removes the high-temperature medium from the reactor jacket and uses its heat energy recovery system to generate hot air for the fluidized bed. This satisfies the hot air drying requirements of the fluidized bed while simultaneously reducing the temperature of the high-temperature medium to 65℃-80℃. At this point, the fluidized bed acts as the first stage of cooling. The medium exiting the fluidized bed can be directly fed into the reactor for high-temperature cooling, or it can be sent to a cooling tower to be cooled to below 32℃ before being sent into the reactor for low-temperature cooling.

[0065] Taking chlorinated polymers as an example, it also saves the energy consumption of the original evaporation cooling process;

[0066] Minimum:

[0067] Qmin=Cm△t=4.2×103J / (kg*℃)×500m3 / h×(90℃-60℃)=4.2×103J / (kg*℃)×500×103kg / h×30℃=63000MJ.

[0068] On the one hand, the heat is extracted for drying, and on the other hand, the amount of circulating water used for cooling is saved. The total energy is shown in the above formula. For a 50,000-ton / year plant, the circulating water volume for heat recovery is 500 m3 / h.

[0069] This invention boasts advantages such as high heat exchange efficiency, small footprint, and significant energy savings. It utilizes the heat from chlorination reactions or other exothermic reactions in the subsequent product drying process. By leveraging the inherent fluidization stage in the production process, it achieves cooling of the high-temperature medium and uses the heat released from the exothermic reaction as the production of hot air for fluidized bed drying. This allows the fluidized bed to perform both fluidized drying and cooling functions, greatly reducing energy consumption. Simultaneously, the heat exchange area / volume ratio of the tube-fin heat exchanger is ≥280 m² / m³, increasing the heat exchange area without increasing the heat exchanger volume. Only the existing blower heat exchange space of the fluidized bed needs to be modified with a tube-fin heat exchanger, reducing energy consumption without increasing the footprint or volume.

[0070] Traditional heat exchangers are DN25 or DN32 tube-fin heat exchangers, which are quite large. If steam heat exchange is used, a heat exchange area of ​​approximately 1250 m² is sufficient to meet drying requirements. When using a DN25 tube-fin heat exchanger, the heat exchange area / heat exchanger volume ratio is 8.4 m² / m³. However, if hot water heat exchange is used, the volume becomes even larger, failing to meet the relevant performance requirements of fluidized bed drying. For example, it results in higher air resistance, insufficient airflow, a larger footprint, limited installation space, and lower equipment reliability.

[0071] Because the inlet air temperature of conventional fluidized beds is relatively low, the original steam heat exchangers can be completely replaced by hot water heat exchangers; alternatively, some of the original steam heat exchangers can be retained. Hot water is pumped into the tube-fin heat exchange tubes 2 using a hot water pump. The diameter of the heat exchange tubes 2 in this invention is ≤4mm, and each small heat exchange tube 2 is equipped with hydrophobic aluminum fins to increase the heat exchange area. Thus, for the same space, compared to heat exchangers with heat exchange tube diameters of 25mm or 32mm, the heat exchange area is more than doubled, while the air resistance is ≤300pa, ensuring stable operation of the fluidized bed drying process.

[0072] This approach utilizes excess reaction heat in the drying process, saving overall steam consumption. Estimates suggest an energy saving of approximately 1 ton of steam per hour for chlorinated polymer products, equivalent to a saving of about 0.4 tons of steam per ton of product. Furthermore, it reduces the electricity consumption of cooling towers and the water consumption for cooling. In total, this results in a saving of approximately 0.5 tons of steam per ton of product.

[0073] The heat exchanger can be installed either after or before the fan.

[0074] This invention utilizes the heat from chlorination or other exothermic reactions in the subsequent product drying process. Since the inlet air temperature of conventional fluidized beds is relatively low, the original steam heat exchangers can be completely replaced by hot water heat exchangers; alternatively, some of the original steam heat exchangers can be retained. Hot water is pumped into heat exchange tubes 2 with a diameter ≤4mm using a hot water pump. Each small heat exchange tube 2 is equipped with hydrophobic aluminum fins to increase the heat exchange area. Specific design modifications can be made according to existing temperature requirements. In this way, the heat exchange area is more than doubled within the same space, while the air resistance is ≤300pa, ensuring stable operation of the fluidized bed drying process.

[0075] The following is the calculation of the ratio of heat exchange area to equipment volume:

[0076]

[0077] This evaluation parameter is called the heat exchanger surface density (m2 / m3), and it is a key parameter characterizing the compactness of a heat exchanger.

[0078] According to conventional product layout, our heat exchanger tube density can reach 1500 (m2 / m3).

[0079]

[0080] Example 2

[0081] In this invention, a heat recovery device based on a small-diameter dual-function heat recovery system is applicable, comprising a tube-fin heat exchanger; the tube-fin heat exchanger includes a shell 1 and finned bodies 11 inside the shell 1; multiple finned bodies 11 are arranged adjacent to each other; the finned bodies 11 are evenly distributed in the left-right direction inside the shell 1; multiple finned bodies 11 form movable gaps 12 with the front and rear inner walls of the shell 1; multiple baffles 13 are fixedly connected within the movable gaps 12; the baffles 13 are in sealing contact with the finned bodies 11 and with the inner wall of the shell 1; the baffles 13 within two movable gaps 12... The shell 1 is staggered on the left and right sides; the front side of the shell 1 is connected to the air inlet connector 14; the rear side of the shell 1 is connected to the air outlet connector 15; the air inlet connector 14 and the air outlet connector 15 are set far apart from each other on the left and right sides of the shell 1; multiple heat exchange tubes 2 are arranged through the left and right sides of the shell 1; the multiple heat exchange tubes 2 are in contact with the fin body 11; the left side of the shell 1 is fixedly connected to the liquid inlet tank 3; the lower inner wall of the liquid inlet tank 3 is fixedly connected to the liquid inlet valve 31; the right side of the shell 1 is fixedly connected to the liquid outlet tank 4; the lower inner wall of the liquid outlet tank 4 is fixedly connected to the liquid outlet valve 41; one end of the heat exchange tube 2 is connected to the liquid inlet tank 3, and the other end is connected to the liquid outlet tank 4.

[0082] During operation, after the operator introduces steam or hot water into the inlet tank 3 through the inlet valve 31, the steam or hot water enters the inside of the multiple heat exchange tubes 2 because the inlet tank 3 is connected to one end of the multiple heat exchange tubes 2. When the inlet valve 31 starts to introduce the heated fluid, room temperature air is introduced into the housing 1 through the air inlet connector 14. The room temperature air enters the movable gap 12 on the front side of the fin body 11. Since the movable gap 12 is separated by multiple baffles 13, and the baffles 13 in the two movable gaps 12 are staggered in the left and right directions, the room temperature air passes through the multiple fin bodies 11 in the front movable gap 12 and enters the rear movable gap 12. The gas in the rear movable gap 12 then enters the front movable gap 12 again along the multiple fin bodies 11. The gas moves back and forth through the finned body 11 in the shell 1 while moving to the left. The gas coils and moves back and forth, thus prolonging the residence time of the gas in the shell 1. The gas carries away the heat from the finned body 11. The heat of the fluid in the heat exchange tube 2 transfers energy to the gas in the shell 1 through the finned body 11, causing the gas to heat up and achieving heat exchange. The heated gas is finally discharged through the gas outlet 15 for use. As the fluid in the heat exchange tube 2 exchanges heat with the air, if one of the heat exchange tubes 2 becomes blocked, the fluid can flow along the other unblocked heat exchange tubes 2 because multiple heat exchange tubes 2 are connected in parallel, abandoning the series connection method of traditional finned heat exchangers. This allows the tube-fin heat exchanger to operate normally.

[0083] It should be noted that the style or structure of the air inlet connector 14 and the air outlet connector 15 in this invention includes, but is not limited to, the style or structure shown in the accompanying drawings. They can also be non-standard styles such as round tubes or square tubes. In actual applications, they can be customized according to the actual heat exchange. Of course, the diameter of the air inlet connector 14 and the air outlet connector 15 can also be customized according to the actual air intake and exhaust volume, and is not limited to the diameter of the air inlet connector 14 and the air outlet connector 15 shown in the accompanying drawings. Furthermore, the diameter of the air inlet connector 14 and the air outlet connector 15 can also be reasonably set according to the actual volume of the heat recovery device. This invention does not impose too many limitations here. Example 3

[0084] The inner wall of the liquid inlet tank 3 is movably and sealed with a liquid inlet plate 32; a left rod 33 is fixedly connected to the upper surface of the liquid inlet plate 32; a left hole 34 is provided through the upper part of the inner wall of the liquid inlet tank 3; the upper end of the left rod 33 passes through the left hole 34 and is fixedly connected to a movable plate 5; a gap is left between the left hole 34 and the outer wall of the left rod 33; the lower surface of the movable plate 5 is connected to the upper surface of the housing 1 by a tension spring 51.

[0085] In this embodiment, the inner wall of the liquid outlet tank 4 is movably and sealed with a liquid outlet plate 42; a right rod 43 is fixedly connected to the upper surface of the liquid outlet plate 42; a right hole 44 is provided through the upper part of the inner wall of the liquid outlet tank 4; the upper end of the right rod 43 passes through the right hole 44 and is fixedly connected to the lower surface of the movable plate 5; a gap is left between the right hole 44 and the outer wall of the right rod 43; a one-way valve is provided at each end of the heat exchange tube 2, with one end flowing in and the other end flowing out.

[0086] During operation, steam and hot water are produced by a reaction, resulting in fluctuating flow rates. When the fluid flow rate entering through the inlet valve 31 is high, more heat exchange tubes 2 are needed to ensure heat exchange efficiency. Conversely, when the fluid flow rate entering through the inlet valve 31 is low, too many heat exchange tubes 2 will prevent the fluid from completely filling them, affecting the heat exchange effect. Therefore, an inlet plate 32 is movably and sealed within the inlet tank 3. Under the action of the pump, the fluid enters the inlet tank 3 through the inlet valve 31, where it compresses the inlet plate 32. The higher the fluid flow rate entering the inlet tank 3, the greater the pressure exerted on the inlet plate 32, and vice versa. Thus, when the flow rate increases, the inlet plate 32 is pressurized and rises. This upward movement connects more heat exchange tubes 2 to the space below the inlet plate 3, allowing more heat exchange tubes 2 to operate. The number of operating heat exchange tubes 2 increases with the fluid flow rate. During the upward movement of plate 32, the gas above the inlet plate 32 will be squeezed out along the left hole 34. The fluid inside the heat exchange tube 2 above the inlet plate 32 cannot flow out due to the one-way valve at the end. During the upward movement of the inlet plate 32, the left rod 33 will move upward, and the left rod 33 will move upward, which will also move the movable plate 5 upward. During the upward movement of the movable plate 5, the tension spring 51 will be pulled, so that the upward movement of the inlet plate 32 and the movable plate 5 needs to overcome the tension of the tension spring 51. During the upward movement of the movable plate 5, the right rod 43 will move upward. 3 will cause the liquid outlet plate 42 to move upward, so that the liquid outlet plate 42 moves upward synchronously in the liquid outlet tank 4 along with the upward movement of the liquid inlet plate 32. During the upward movement of the liquid outlet plate 42, more heat exchange tubes 2 will be activated. Importantly, during the upward movement of the liquid outlet plate 42, the gas in the space of the liquid outlet tank 4 above the liquid outlet plate 42 is discharged along the right hole 44. Under the pressure balance at both ends of the unactivated heat exchange tubes 2, it is difficult for the fluid inside the unactivated heat exchange tubes 2 to flow out, while the one-way valves at both ends of the activated heat exchange tubes 2 open under the fluid flow.

[0087] When the flow rate entering the inlet tank 3 decreases, the inlet plate 32 will move downward under the tension of the tension spring 51. During the downward movement of the inlet plate 32, the movable plate 5 and the outlet plate 42 will move downward simultaneously, thus disconnecting more heat exchange tubes 2 from the flow of the inlet valve 31. In summary, this embodiment uses the inlet plate 32, which is movably connected in the inlet tank 3, and the outlet plate 42, which is movably connected in the outlet tank 4, so that the number of heat exchangers in the tube-fin heat exchanger can be adapted to the change in the amount of fluid entering. Thus, on the one hand, if the number of heat exchange tubes 2 is too small, it will affect the heat recovery efficiency; on the other hand, it will avoid the heat recovery effect being affected by insufficient fluid in the heat exchange tubes 2. Example 4

[0088] The top wall of the housing 1 is provided with a front hole 16 and a rear hole 17; the front hole 16 is located directly above the front movable gap 12; the rear hole 17 is located directly above the rear movable gap 12; the front movable gap 12 is divided into multiple front gaps 121 by a baffle 13; a front movable block 52 is movably and sealed within the front gap 121; a front rod 53 is fixedly connected to the upper surface of the front movable block 52; the upper end of the front rod 53 passes through the front hole 16 and is fixedly connected to the lower surface of the movable plate 5; the rear movable gap 12 is divided into multiple rear gaps 122 by the baffle 13; a rear movable block 54 is movably and sealed within the rear gap 122; a rear rod 55 is fixedly connected to the upper surface of the rear movable block 54; the upper end of the rear rod 55 passes through the rear hole 17 and is fixedly connected to the lower surface of the movable plate 5.

[0089] In this embodiment, multiple partitions 18 are evenly distributed on the inner wall of the shell 1; the material of the partitions 18 is the same as that of the fin body 11; the partitions 18 extend forward to the front gap 121 and backward to the rear gap 122; the partitions 18 separate two adjacent heat exchange tubes 2; the vertical thickness of the front movable block 52 and the rear movable block 54 is greater than the distance between adjacent partitions 18; the lengths of the front rod 53, the rear rod 55, the left rod 33 and the right rod 43 are equal.

[0090] During operation, both the air inlet connector 14 and the air outlet connector 15 are located on the lower part of the outer wall of the housing 1. The liquid inlet plate 32 moves up and down as the flow rate of the fluid entering the liquid inlet tank 3 changes. The liquid inlet plate 32, the liquid outlet plate 42, the front movable block 52, and the rear movable block 54 are at the same height. When the liquid inlet plate 32 moves upward, it will drive the left rod 33 to move upward. When the left rod 33 moves upward, it will drive the movable plate 5 to move upward. When the movable plate 5 moves upward, it will drive the front rod 53, the rear rod 55, and the right rod 43 to move upward. When the right rod 43 moves upward, it will drive the liquid outlet plate 42 to move upward. When the front rod 53 moves upward, it will drive the front movable block 52 to move upward. The front movable block 52 moves within the front gap 121. The upward height of the front movable block 52 directly affects the range through which the airflow passes through the fin body 11. When the rear rod 55 moves upward, it will drive the rear movable block 54 to move upward. The rear movable block 54 moves within the rear gap 121. Within the gap 122, the rear movable block 54 moves at the same height as the front movable block 52 and moves upward synchronously. The distance between adjacent partitions 18 is less than the thickness of the front movable block 52 and the rear movable block 54. Thus, through the cooperation of the front movable block 52 and the rear movable block 54, the space around the activated heat exchange tube 2 and the unactivated heat exchange tube 2 inside the shell 1 is separated. This allows the gas entering the shell 1 to concentrate on exchanging heat with the fin body 11 around the activated heat exchange tube 2, further ensuring the heat recovery effect. Similarly, during the downward movement of the liquid inlet plate 32, the left rod 33 will move downward. During the downward movement of the left rod 33, the movable plate 5 will move downward. During the downward movement of the movable plate 5, the front movable block 52 and the rear movable block 54 will move upward, thus separating the space around the activated heat exchange tube 2 and the unactivated heat exchange tube 2 again. The front movable block 52 and the rear movable block 54 move with the movement of the liquid inlet plate 32. Example 5

[0091] The upper surfaces of the shell 1, the inlet tank 3, and the outlet tank 4 are flush; a protective shell 6 is fixedly connected to the upper surfaces of the shell 1, the inlet tank 3, and the outlet tank 4; the inner wall of the protective shell 6 is movably and sealed to the outer wall of the movable plate 5; the movable plate 5 extends vertically and is movably and sealed to a compensation block 56; the compensation block 56 is fixedly connected to the shell 1; the space between the lower surface of the movable plate 5 and the upper surface of the shell 1 is called the storage cavity 57; the gas in the inlet tank 3, the outlet tank 4, and the movable gap 12 can enter the storage cavity 57 for clearance storage.

[0092] During operation, as the inlet plate 32 moves upward, it forces the gas in the inlet tank 3 into the storage chamber 57 through the left hole 34. During this upward movement, the inlet plate 32 also drives the outlet plate 42 upward via the movable plate 5. As the outlet plate 42 moves upward, it forces the gas in the outlet tank 4 into the storage chamber 57 through the right hole 44. The front movable block 52 in the front gap 121 moves upward along with the movable plate 5, and it forces the gas in the front gap 121 into the storage chamber 57 through the front hole 16 for temporary storage. The rear movable block 54 then forces the gas in the rear gap 121 into the storage chamber 57 through the front hole 16. The gas inside 22 is squeezed into the storage chamber 57 through the rear hole 17 for temporary storage. During the downward movement of the liquid inlet plate 32, the gas in the storage chamber 57 returns to the liquid inlet tank 3, the movable gap 12 and the liquid outlet tank 4. In this way, the storage chamber 57 is designed to seal the gas that is squeezed out and replenished inside the liquid inlet tank 3, the movable gap 12 and the liquid outlet tank 4, so as to prevent the liquid inlet tank 3, the movable gap 12 and the liquid outlet tank 4 from being contaminated by external substances, and to prevent the external gas from carrying away the residual heat in the liquid inlet tank 3, the movable gap 12 and the liquid outlet tank 4, thus ensuring the heat recovery effect.

[0093] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in Figure 4. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0094] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A heat recovery system based on a small-diameter dual-function pipe, characterized in that, The system includes an insulated medium storage tank, multiple heat exchange venting spaces, each containing its own tube-fin heat exchanger; the diameter of the heat exchange tubes in each tube-fin heat exchanger is ≤4mm; each tube-fin heat exchanger has its own inlet valve and outlet valve; an inlet pump is installed at the output end of the medium storage tank, and the inlet pump is connected to each inlet valve via branch pipelines; the heat exchange area / volume of each tube-fin heat exchanger is ≥280m² / m³; the airflow inlet of each heat exchange venting space is connected to its respective blower, and the air temperature output from the heat exchange venting space is 65℃-85℃; the medium storage tank has at least one first medium inlet that allows heat transfer media with a temperature higher than 95℃ to be input into it.

2. The heat recovery system based on small-diameter dual-function pipes according to claim 1, characterized in that: The medium storage tank has at least one second medium inlet that allows heat transfer medium at temperatures below 80°C to be input into it. The medium output from each outlet valve is input into the second medium inlet of the medium storage tank via a return pipe and a return valve; or, the medium output from each outlet valve is input into the second medium inlet of the medium storage tank via a return pipe and a return valve through a cooling tower.

3. A heat recovery device based on a small-diameter dual-function pipe, applicable to the heat recovery system based on a small-diameter dual-function pipe as described in claim 1, characterized in that: The device includes a tube-fin heat exchanger; the tube-fin heat exchanger includes a shell and finned bodies inside the shell; multiple finned bodies are arranged adjacent to each other; the finned bodies are evenly distributed in the left-right direction inside the shell; multiple finned bodies form movable gaps with the front and rear inner walls of the shell; multiple baffles are fixedly connected within the movable gaps; the baffles are in sealing contact with the finned bodies and the inner walls of the shell; the baffles in two movable gaps are staggered in the left-right direction; an air inlet connector is connected to the front side of the shell; an air outlet connector is connected to the rear side of the shell; the air inlet connector and the air outlet connector are arranged far apart from each other in the left-right direction of the shell; multiple heat exchange tubes are arranged through the left and right sides of the shell; the multiple heat exchange tubes are in contact with the finned bodies; a liquid inlet tank is fixedly connected to the left side of the shell; an inlet valve is fixedly connected to the lower inner wall of the liquid inlet tank; an outlet tank is fixedly connected to the right side of the shell; an outlet valve is fixedly connected to the lower inner wall of the outlet tank; one end of each heat exchange tube is connected to the liquid inlet tank, and the other end is connected to the outlet tank.

4. The heat recovery device based on small-diameter dual-function pipes according to claim 3, characterized in that: The inner wall of the liquid inlet tank is movably and sealed with an inlet plate; a left rod is fixedly connected to the upper surface of the inlet plate; a left hole is provided through the upper part of the inner wall of the liquid inlet tank; the upper end of the left rod passes through the left hole and is fixedly connected to a movable plate; a gap is left between the left hole and the outer wall of the left rod; the lower surface of the movable plate is connected to the upper surface of the shell by a tension spring.

5. The heat recovery device based on a small-diameter dual-function pipe as described in claim 4, characterized in that: The inner wall of the liquid outlet tank is movably and sealed with an outlet plate; a right rod is fixedly connected to the upper surface of the outlet plate; a right hole is provided through the upper part of the inner wall of the liquid outlet tank; one end of the right rod passes through the right hole and is fixedly connected to the lower surface of the movable plate; a gap is left between the right hole and the outer wall of the right rod; a one-way valve is provided at the end of each heat exchange tube, with one end flowing in and the other end flowing out.

6. The heat recovery device based on a small-diameter dual-function pipe as described in claim 5, characterized in that: The top wall of the housing is provided with a front hole and a rear hole; the front hole is located directly above the front movable gap; the rear hole is located directly above the rear movable gap; the front movable gap is divided into multiple front gaps by a baffle; a front movable block is movably and sealed within the front gap; a front rod is fixedly connected to the upper surface of the front movable block; the upper end of the front rod passes through the front hole and is fixedly connected to the lower surface of the movable plate; the rear movable gap is divided into multiple rear gaps by a baffle; a rear movable block is movably and sealed within the rear gap; a rear rod is fixedly connected to the upper surface of the rear movable block; the upper end of the rear rod passes through the rear hole and is fixedly connected to the lower surface of the movable plate.

7. The heat recovery device based on a small-diameter dual-function pipe as described in claim 6, characterized in that: Multiple partitions are evenly distributed on the inner wall of the shell; the partitions are made of the same material as the fin body; the partitions extend forward to the front gap and backward to the rear gap; the partitions separate two adjacent heat exchange tubes; the vertical thickness of the front movable block and the rear movable block is greater than the distance between adjacent partitions; the lengths of the front rod, rear rod, left rod and right rod are equal.

8. The heat recovery device based on small-diameter dual-function pipes according to claim 5, characterized in that: The upper surfaces of the shell, inlet tank, and outlet tank are flush; a protective shell is fixedly connected to the upper surfaces of the shell, inlet tank, and outlet tank; the inner wall of the protective shell is movably and sealingly connected to the outer wall of the movable plate; a compensation block is movably and sealingly connected to the upper and lower parts of the movable plate; the compensation block is fixedly connected to the shell; the space between the lower surface of the movable plate and the upper surface of the shell is called the storage cavity; The gas in the inlet tank, outlet tank, and movable gap can enter the storage chamber for storage.

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