VOCs Regenerative Catalytic Combustion Waste Heat Utilization System

Abstract

The present invention discloses a waste heat utilization system for regenerative catalytic combustion of VOCs, comprising: a drying production chamber, a first heat exchange unit and a regenerative catalytic combustion unit. One end of the drying production chamber is provided with a drying gas inlet, and the other end is provided with a VOC gas collection port. The first heat exchange unit is provided with a high-temperature purified gas inlet, a medium-temperature purified gas outlet, a cold VOC gas inlet and a hot VOC gas outlet. The cold VOC gas inlet is connected to the VOC waste gas collection port through a pipeline; the regenerative catalytic combustion unit includes a hot VOC gas inlet and a high-temperature purified gas outlet. The hot VOC gas inlet is connected to the hot VOC gas outlet of the first heat exchange unit through a pipeline, and the high-temperature purified gas outlet is connected to the high-temperature purified gas inlet of the first heat exchange unit through a pipeline, so that the high-temperature purified gas generated after catalytic combustion of VOC gas enters the first heat exchange unit to exchange heat with the cold VOC gas.

Description

Technical Field

[0001] The present invention relates to a waste heat utilization system, and particularly to a waste heat utilization system for VOCs gas combustion. Background Art

[0002] VOC (Volatile Organic Compound) refers to the general term of volatile organic compounds at normal temperature. VOC waste gas contains formaldehyde, xylene, toluene, acetone, methyl ethyl ketone, halogen compounds, etc. A large amount of VOC waste gas will be generated during the production and use processes in industries such as petrochemical, pharmaceutical, paint, coating, electronic manufacturing, surface anti-corrosion, shoemaking, printing, and transportation. Most of these compounds have pungent odors, which not only have a great impact on air quality but also pose a hazard to human health when directly contacted. Moreover, the flammable characteristics of VOC waste gas also cause safety hazards.

[0003] Currently, due to the large emission volume, diverse types, difficult degradation, strong toxicity, and great safety hazards of VOCs gas, it has become the focus of air treatment problems in various countries. In the prior art, the main technologies for treating VOC waste gas include: catalytic combustion, activated carbon adsorption, low-temperature plasma, ultraviolet light irradiation, etc. Among them, the most ideal way to treat VOC waste gas is to raise the temperature of the VOC waste gas to above 800 degrees Celsius by relying on its own combustion heat or the combustion of a burner in a combustion furnace, so that the VOCs in the waste gas are decomposed into CO2 and water, and then these gases are discharged into the atmosphere.

[0004] For example, a method for treating VOCs gas by low-temperature regenerative catalytic oxidation disclosed in Chinese Patent Application CN105066148A. The VOCs gas enters the pretreatment system after passing through the VOCs high-concentration recovery device. The pretreated gas enters the cold side of the heat exchanger through a fan. The gas at the outlet of the cold side of the heat exchanger enters the heating chamber. The gas heated in the heating chamber successively enters the low-temperature catalytic oxidation bed, high-temperature catalytic oxidation bed, and honeycomb ceramic regenerator. The gas at the outlet of the honeycomb ceramic regenerator enters the hot side of the heat exchanger. The gas at the outlet of the hot side of the heat exchanger enters the chimney. The technical solution in which the on-line concentration analysis system is connected to the inlet pipeline of the pretreatment system, the outlet pipeline of the fan, and the outlet pipeline of the hot side of the heat exchanger better solves the above problems and can be used for treating VOCs gas. However, this method for treating VOCs gas by low-temperature regenerative catalytic oxidation has the following disadvantages or deficiencies: (1) A large amount of external heat energy is required for the low-temperature catalytic oxidation bed and the high-temperature catalytic oxidation bed; (2) The energy of the VOCs gas itself is not fully utilized.

[0005] For another example, a regenerative VOCs catalytic oxidation device and process disclosed in Chinese Patent Application CN106582262A includes a catalytic oxidation device. The catalytic oxidation device includes a box body, a catalyst layer, a heat storage layer and optionally a temperature sensor disposed inside the box body. An organic waste gas inlet, a purified gas outlet and a cleaning gas inlet are provided on the box body. The organic waste gas inlet is connected to the waste gas inlet pipe to be treated through a valve, the purified gas outlet is connected to the purified gas outlet pipe through a valve, and the cleaning gas inlet is connected to the cleaning gas inlet pipe through a valve. The regenerative VOCs catalytic oxidation device includes at least three catalytic oxidation devices interconnected through a connecting device. However, the VOCs catalytic oxidation device and process have the following disadvantages or deficiencies: (1) The waste heat energy after the catalytic oxidation of VOCs gas is not fully utilized; (2) There are potential safety hazards during the catalytic oxidation of VOCs gas, and catalyst poisoning is likely to occur.

[0006] Therefore, it has become an urgent problem in the industry to provide a VOCs regenerative catalytic combustion waste heat utilization system that can effectively decompose VOCs gas and fully utilize the heat energy of VOCs catalytic combustion. Summary of the Invention

[0007] The object of the present invention is to provide a VOCs regenerative catalytic combustion waste heat utilization system that can fully utilize the heat energy of the catalytic combustion of VOCs gas, not only effectively decompose VOCs gas, but also the heat generated by decomposing VOCs gas can be used for heat exchange of VOCs gas itself. At the same time, cold air can be preheated to form hot air for use as drying gas in the drying production room.

[0008] To achieve the above object, the present invention provides a VOCs regenerative catalytic combustion waste heat utilization system, including: a drying production room, a first heat exchange unit and a regenerative catalytic combustion unit. Among them, the drying production room includes a drying cavity. One end of the drying cavity is provided with a drying gas inlet, and the other end is provided with a VOCs gas collection port. The first heat exchange unit is provided with a high-temperature purified gas inlet, a medium-temperature purified gas outlet, a cold VOCs gas inlet, and a hot VOCs gas outlet. The medium-temperature purified gas outlet is communicated with a chimney. The cold VOCs gas inlet is connected to the VOC waste gas collection port of the drying cavity through a pipeline, so that cold VOCs gas enters the first heat exchange unit for heat exchange to form hot VOCs gas. The regenerative catalytic combustion unit includes a hot VOCs gas inlet and a high-temperature purified gas outlet. Among them, the hot VOCs gas inlet is connected to the hot VOCs gas outlet of the first heat exchange unit through a pipeline, and the high-temperature purified gas outlet is connected to the high-temperature purified gas inlet of the first heat exchange unit through a pipeline, so that the high-temperature purified gas generated after catalytic combustion of VOCs gas enters the first heat exchange unit to exchange heat with cold VOCs gas.

[0009] Among them, the product coated with the coating is conveyed along with the conveyor belt in the drying production chamber. Under the action of the drying gas, the coating is gradually dried to form a paint film adhering to the product, and the VOCs gas formed by the volatilization of the organic matter in the coating during drying is gradually discharged from the VOCs gas collection port.

[0010] Optionally, it further includes a filter connected between the drying production chamber and the first heat exchange unit. The filter is provided with a filter inlet and a filter outlet. The filter inlet is connected to the VOCs gas collection port of the drying production chamber through a pipeline, and the filter outlet is connected to the cold VOCs gas inlet of the first heat exchange unit through a VOCs gas pipeline to filter out the particles in the VOCs gas generated in the drying production chamber and transport them to the first heat exchange unit.

[0011] Optionally, the first heat exchange unit includes: an outer housing, a first side longitudinal partition, a first intermediate longitudinal partition, a second intermediate longitudinal partition, and a second side longitudinal partition sequentially arranged in the inner cavity of the outer housing along the transverse direction of the outer housing, a first chamber formed between one side wall of the outer housing and the first side longitudinal partition, a first ventilation chamber formed between the first side longitudinal partition and the first intermediate longitudinal partition, a spacer chamber formed between the first intermediate longitudinal partition and the second intermediate longitudinal partition, a second ventilation chamber formed between the second intermediate longitudinal partition and the second side longitudinal partition, a second chamber formed between the other side wall of the outer housing and the second side longitudinal partition, a first transverse partition arranged in the first chamber and horizontally extending from the center of one side wall of the outer housing to the first side longitudinal partition, a spacer transverse partition arranged in the spacer chamber and horizontally extending from the center of the first intermediate longitudinal partition to the second intermediate longitudinal partition, and a second transverse partition arranged in the second chamber and horizontally extending from the center of the second side longitudinal partition to the other side wall of the outer housing. Among them, the first transverse partition divides the first chamber into a first upper gas chamber and a first lower gas chamber from top to bottom, the spacer transverse partition divides the spacer chamber into a spacer upper gas chamber and a spacer lower gas chamber from top to bottom, the second transverse partition divides the second chamber into a second upper gas chamber and a second lower gas chamber from top to bottom. A first plate fin heat exchanger is arranged in the first ventilation chamber, a second plate fin heat exchanger is arranged in the second ventilation chamber, the cold VOCs gas inlet is arranged on the outer side wall of the first upper gas chamber, the hot VOCs gas outlet is arranged on the outer side wall of the second upper gas chamber, the high-temperature purified gas inlet is arranged on the outer side wall of the second lower gas chamber, and the medium-temperature purified gas outlet is arranged on the outer side wall of the first lower gas chamber.

[0012] Optionally, the first plate-fin heat exchanger and the second plate-fin heat exchanger respectively include at least two rows of first fluid heat exchange tubes and at least two rows of second fluid heat exchange tubes. Among them, at least two rows of first fluid heat exchange tubes and at least two rows of second fluid heat exchange tubes are cross-laminated with each other. Each row of first fluid heat exchange tubes and each row of second fluid heat exchange tubes respectively include at least four finned plain tubes. Each row of first fluid heat exchange tubes of the first plate-fin heat exchanger extends obliquely downward from the first side longitudinal partition at the first upper gas chamber to the first intermediate longitudinal partition of the spaced lower gas chamber. Each row of first fluid heat exchange tubes of the second plate-fin heat exchanger extends obliquely upward from the second intermediate longitudinal partition of the spaced lower gas chamber to the second side longitudinal partition of the second upper gas chamber. Each row of second fluid heat exchange tubes of the first plate-fin heat exchanger extends obliquely upward from the first side longitudinal partition at the first lower gas chamber to the first intermediate longitudinal partition of the spaced upper gas chamber. Each row of second fluid heat exchange tubes of the second plate-fin heat exchanger extends obliquely downward from the second intermediate longitudinal partition of the spaced upper gas chamber to the second side longitudinal partition of the second lower gas chamber.

[0013] Optionally, through holes communicating with the first ends of each row of first fluid heat exchange tubes and each row of second fluid heat exchange tubes of the first plate-fin heat exchanger are provided on the first side longitudinal partition. Through holes communicating with the second ends of each row of first fluid heat exchange tubes and each row of second fluid heat exchange tubes of the first plate-fin heat exchanger are provided on the first intermediate longitudinal partition. Through holes communicating with the first ends of each row of first fluid heat exchange tubes and each row of second fluid heat exchange tubes of the second plate-fin heat exchanger are provided on the second intermediate longitudinal partition. Through holes communicating with the second ends of each row of first fluid heat exchange tubes and each row of second fluid heat exchange tubes of the second plate-fin heat exchanger are provided on the second side longitudinal partition.

[0014] Optionally, the regenerative catalytic combustion unit includes: a heating chamber, a catalytic chamber, and a regenerative chamber connected in sequence through pipelines. Among them, the heating chamber is used for reheating and heating the hot VOCs gas entering the regenerative catalytic combustion unit; the catalytic chamber is used for catalytic oxidation of the VOCs gas heated by the catalyst to decompose and form high-temperature purified gas; the regenerative chamber is used for collecting the heat of the high-temperature purified gas to preheat the subsequent VOCs gas entering the regenerative catalytic combustion unit.

[0015] Optionally, the heating medium of the heating chamber is natural gas or electric heating tubes.

[0016] Preferably, the catalyst in the catalytic chamber is a honeycomb-type noble metal catalyst.

[0017] More preferably, the catalyst in the catalytic chamber is Pd and / or Pt.

[0018] Optionally, the regenerative catalytic combustion unit further includes a treatment chamber provided between the heating chamber and the catalytic chamber. The treatment chamber is used for removing the catalyst poisons contained in the hot VOCs gas.

[0019] Among them, the catalyst poison refers to a substance that makes the catalyst lose its catalytic activity.

[0020] More specifically, the catalyst poison can be Pb, Zn, and Hg.

[0021] Preferably, the heat storage material in the regenerator is heat storage ceramics or cast iron balls.

[0022] Among them, the VOCs gas at 80 - 90 °C from the drying production chamber forms a high-temperature VOCs gas at 220 - 240 °C after heat exchange in the first heat exchange unit, and then is further heated in the heating chamber to form a VOCs gas at 250 - 270 °C, which is catalytically combusted and decomposed in the catalytic chamber to form a high-temperature purified gas containing CO2 and H2O at 280 - 300 °C. Then it enters the regenerator to collect the heat of the high-temperature purified gas. The warm purified gas at 280 - 300 °C discharged from the regenerator enters the first heat exchange unit again, and after heat exchange with the cold VOCs gas, it is cooled to form a medium-temperature purified gas at 110 - 130 °C.

[0023] Optionally, a second heat exchange unit is further included. The second heat exchange unit includes a cold air inlet, a hot air outlet, a low-temperature purified gas outlet, and a medium-temperature purified gas inlet. Among them, the medium-temperature purified gas inlet is connected to the medium-temperature purified gas outlet of the first heat exchange unit through a pipeline, the low-temperature purified gas outlet is connected to the chimney through a pipeline, and the hot air outlet is connected to the drying gas inlet of the drying cavity through a hot air pipeline to supply the hot air formed by heat exchange of the cold air from the cold air inlet to the inside of the drying cavity through the hot air pipeline.

[0024] Among them, the medium-temperature purified gas at 110 - 130 °C from the first heat exchange unit exchanges heat with the normal-temperature air at about 20 °C after entering the second heat exchange unit. The air at 70 - 90 °C formed after heat exchange is supplied to the inside of the drying cavity through the hot air pipeline, and the low-temperature purified gas at about 60 °C formed after cooling is discharged to the chimney.

[0025] Optionally, the VOCs gas pipeline is provided with a first VOCs gas pipeline and a second VOCs gas pipeline. The first VOCs gas pipeline is connected to the cold VOCs gas inlet of the first heat exchange unit to supply 60% - 90% of the VOCs gas discharged from the drying cavity to the first heat exchange unit for heat exchange, and the second VOCs gas pipeline is connected to the drying gas inlet of the drying cavity to return 10% - 40% of the VOCs gas to the inside of the drying cavity.

[0026] Optionally, a first safety fan for introducing VOCs gas into the filter is further provided on the pipeline between the drying production chamber and the filter, and a second safety fan for introducing VOCs gas into the treatment chamber is provided on the pipeline between the heating chamber and the treatment chamber.

[0027] Optionally, the VOCs regenerative catalytic combustion waste heat utilization system can be used to treat VOCs gases generated during the drying of paint films or coatings, such as being applied in factories such as automobile factories, parts factories, furniture factories, etc.

[0028] According to the solution of the present invention, electric heating or combustion heating is adopted in the heating chamber, which can ensure that the regenerative catalytic combustion unit operates at a constant temperature when the system starts, so as to improve the VOCs treatment effect without being affected. When the heat storage chamber has completed heat storage, the heating at the heating chamber can be stopped, and the system can automatically operate at a constant temperature, thereby reducing the use cost.

[0029] The beneficial effects of the present invention are: (1) After the VOCs gas is treated in three steps through the treatment chamber, the catalytic chamber and the heat storage chamber, it is completely decomposed and purified, thus ensuring that the discharged gas meets the environmental emission standards; (2) The setting of the first heat exchange unit can further effectively utilize the heat generated by the catalytic combustion decomposition of the VOCs gas, preheat the cold VOCs, achieve energy self-sufficiency, and at the same time, the air can be further heated into hot air for use as drying gas, making full use of the self-energy of the VOCs gas and improving the energy utilization rate; (3) The structures of the first plate fin heat exchanger and the second plate fin heat exchanger in the first heat exchange unit enable cross-layer heat exchange between the high-temperature purified gas and the cold VOCs gas, improving the heat exchange efficiency and being more energy-saving and environmentally friendly; (4) 20% - 40% of the VOCs gas is recycled back into the drying cavity to dry the product paint film in the drying cavity again, realizing the recycling of energy and at the same time reducing the content of nitrogen oxides in the flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The structural schematic diagram of the VOCs regenerative catalytic combustion waste heat utilization system of the present invention is shown.

[0031] Figure 2 The structural schematic diagram of the first heat exchange unit of the present invention is shown.

[0032] Figure 3 The structural schematic diagram of the first fluid heat exchange tubes of the first plate fin heat exchanger and the second plate fin heat exchanger of the present invention is shown.

[0033] Figure 4 The structural schematic diagram of the second fluid heat exchange tubes of the first plate fin heat exchanger and the second plate fin heat exchanger of the present invention is shown.

[0034] Figure 5 The structural schematic diagram of the through holes of the first side longitudinal partition plate of the first heat exchange unit of the present invention is shown. DETAILED DESCRIPTION OF THE INVENTION

[0035] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0036] Please refer to Figure 1 , according to a non - restrictive embodiment of the present invention, the VOCs regenerative catalytic combustion waste heat utilization system includes: a drying production chamber 10, a filter 20, a first heat exchange unit 30, a regenerative catalytic combustion unit 40, a second heat exchange unit 50, and a chimney 60.

[0037] Among them, the drying production chamber 10 includes a drying cavity 110. One end of the drying cavity 110 is provided with a drying gas inlet 120, and the other end of the drying cavity 110 is provided with a VOCs gas collection port 130.

[0038] The first heat exchange unit 30 is provided with a high - temperature purified gas inlet 301, a medium - temperature purified gas outlet 302, a cold VOCs gas inlet 303, and a hot VOCs gas outlet 304.

[0039] The filter 20 is provided with a filter inlet 210 and a filter outlet 220. The filter inlet 210 is connected to the VOCs gas collection port 130 of the drying production chamber 10 through a pipeline, and the filter outlet 220 is connected to the cold VOCs gas inlet 303 of the first heat exchange unit 30 through a VOCs gas pipeline L. After filtering out the particles in the VOCs gas generated by the drying production chamber 10, it is then transported to the first heat exchange unit 30.

[0040] In this non - restrictive embodiment, as Figure 2As shown, the first heat exchange unit 300 includes: a housing 310, a first side longitudinal partition 320, a first intermediate longitudinal partition 330, a second intermediate longitudinal partition 340, a second side longitudinal partition 350, a first transverse partition 360, a spaced transverse partition 370, and a second transverse partition 380. A first chamber A is formed between a side wall of the housing 310 and the first side longitudinal partition 320, a first air exchange chamber B is formed between the first side longitudinal partition 320 and the first intermediate longitudinal partition 330, a spaced chamber C is formed between the first intermediate longitudinal partition 330 and the second intermediate longitudinal partition 340, a second air exchange chamber D is formed between the second intermediate longitudinal partition 340 and the second side longitudinal partition 350, and a second chamber E is formed between the other side wall of the housing and the second side longitudinal partition 350. Among them, the first transverse partition 360 divides the first chamber A into a first upper gas chamber A1 and a first lower gas chamber A2 from top to bottom, the spaced transverse partition 370 divides the spaced chamber C into a spaced upper gas chamber C1 and a spaced lower gas chamber C2 from top to bottom, and the second transverse partition 380 divides the second chamber E into a second upper gas chamber E1 and a second lower gas chamber E2 from top to bottom. A first plate fin heat exchanger T1 is provided in the first air exchange chamber B, a second plate fin heat exchanger T2 is provided in the second air exchange chamber D, a cold VOCs gas inlet 303 is provided on the outer side wall of the first upper gas chamber A1, a hot VOCs gas outlet 304 is provided on the outer side wall of the second upper gas chamber E1, a high-temperature purified gas inlet 301 is provided on the outer side wall of the second lower gas chamber E2, and a medium-temperature purified gas outlet 302 is provided on the outer side wall of the first lower gas chamber A2.

[0041] Specifically, as Figure 3 and Figure 4 shown, the first plate fin heat exchanger T1 includes six rows of first fluid heat exchange tubes T11 and six rows of second fluid heat exchange tubes T12 arranged in a cross-laminated manner with each other. Symmetrically, the second plate fin heat exchanger T2 also includes six rows of first fluid heat exchange tubes T21 and six rows of second fluid heat exchange tubes T22 arranged in a cross-laminated manner with each other. Each row of the first fluid heat exchange tubes T11 (T21) and each row of the second fluid heat exchange tubes T12 (T22) respectively include five finned smooth tubes (as Figure 5 shown). Each row of the first fluid heat exchange tubes T11 of the first plate fin heat exchanger T1 extends obliquely downward from the first side longitudinal partition 320 at the first upper gas chamber A1 to the first intermediate longitudinal partition 330 of the spaced lower gas chamber C2, and each row of the first fluid heat exchange tubes T21 of the second plate fin heat exchanger T2 extends obliquely upward from the second intermediate longitudinal partition 340 of the spaced lower gas chamber C2 to the second side longitudinal partition 350 of the second upper gas chamber E1 (as Figure 3As shown). Each row of the second-fluid heat exchange tubes T12 of the first plate-fin heat exchanger T1 extends obliquely upward from the first side longitudinal partition 320 at the first lower air chamber A2 to the first intermediate longitudinal partition 330 of the spaced upper air chamber C1, and each row of the second-fluid heat exchange tubes T22 of the second plate-fin heat exchanger T2 extends obliquely downward from the second intermediate longitudinal partition 340 of the spaced upper air chamber C1 to the second side longitudinal partition 350 of the second lower air chamber E2 (as Figure 4 shown).

[0042] In this non-limiting embodiment, through holes 3208 communicating with the first ends of each row of the first-fluid heat exchange tubes T11 and each row of the second-fluid heat exchange tubes T12 of the first plate-fin heat exchanger T1 are provided on the first side longitudinal partition 320, and through holes (not shown in the figure) communicating with the second ends of each row of the first-fluid heat exchange tubes T11 and each row of the second-fluid heat exchange tubes T12 of the first plate-fin heat exchanger T1 are provided on the first intermediate longitudinal partition 330. Similarly, through holes (not shown in the figure) communicating with the first ends of each row of the first-fluid heat exchange tubes T21 and each row of the second-fluid heat exchange tubes T22 of the second plate-fin heat exchanger T2 are provided on the second intermediate longitudinal partition 340, and through holes (not shown in the figure) communicating with the second ends of each row of the first-fluid heat exchange tubes T21 and each row of the second-fluid heat exchange tubes T22 of the second plate-fin heat exchanger T2 are provided on the second side longitudinal partition 350. Taking the first side longitudinal partition 320 as an example, as Figure 5 shown, six rows of through holes 3208 are provided in the upper and lower longitudinal parts of the first side longitudinal partition 320, and five through holes are evenly distributed horizontally on each row of through holes, so that VOCs gas or purified gas can pass through. As Figure 5 shown, the through holes (separated by the first transverse partition 360) in the upper and lower longitudinal parts of the first side longitudinal partition 320 are staggered by a certain distance in the horizontal direction in parallel columns, so that the six rows of the first-fluid heat exchange tubes T11 and the six rows of the second-fluid heat exchange tubes T12 of the first plate-fin heat exchanger T1 can be arranged in a cross-layered manner with each other.

[0043] Thus, the cold VOCs gas at about 80 °C enters the first upper gas chamber A1 from the cold VOCs gas inlet 303, enters the first ventilation chamber B along each row of the first fluid heat exchange tubes T11 of the first plate fin heat exchanger T1 through the through holes on the first side longitudinal partition 320, then enters the spaced lower gas chamber C2 through the first intermediate longitudinal partition 330, and then enters the second ventilation chamber D along each row of the first fluid heat exchange tubes T21 of the second plate fin heat exchanger T2 through the through holes on the second intermediate longitudinal partition 340. After heat exchange, it enters the second upper gas chamber E1 through the through holes on the second side longitudinal partition 350, and the formed hot VOCs gas at about 230 °C is discharged from the hot VOCs gas outlet 304 provided at the outer side wall of the second upper gas chamber E1 to the regenerative catalytic combustion unit 40. At the same time, the high-temperature purified gas at 280 - 290 °C enters the second lower gas chamber E2 from the high-temperature purified gas inlet 301, enters the second ventilation chamber D along each row of the second fluid heat exchange tubes T22 of the second plate fin heat exchanger T2 through the through holes on the second side longitudinal partition 350, then enters the spaced upper gas chamber C1 through the second intermediate longitudinal partition 340, and then enters the first ventilation chamber B along each row of the second fluid heat exchange tubes T12 of the first plate fin heat exchanger T1 through the through holes on the first intermediate longitudinal partition 330. After heat exchange, it enters the first lower gas chamber A2 through the through holes on the first side longitudinal partition 320, and the formed medium-temperature purified gas is discharged from the medium-temperature purified gas outlet 302 provided at the outer side wall of the first lower gas chamber A2.

[0044] As Figure 1 shown, the regenerative catalytic combustion unit 40 includes: a heating chamber 410, a treatment chamber 420, a catalytic chamber 430, and a regenerative chamber 440. Among them, the heating chamber 410 reheats and heats the hot VOCs gas entering the regenerative catalytic combustion unit 40 through the hot VOCs gas inlet 401. Here, it can be heated by the heat generated by burning natural gas or by electric heating tubes, so as to reheat the hot VOCs gas at about 230 °C to about 260 °C. Then, the treatment chamber 420 is used to not only remove the catalyst poisons contained in the hot VOCs gas, but also perform pretreatment on the substances that cannot be processed by the subsequent catalyst. Then, the noble metals Pd and / or Pt in the catalytic chamber 430 are used to catalytically oxidize the VOCs gas, so as to decompose it into a high-temperature purified gas at about 290 °C containing CO2 and H2O. The regenerative chamber 440 can collect the heat of the high-temperature purified gas, preheat the VOCs gas entering the regenerative catalytic combustion unit subsequently, and transport the discharged high-temperature purified gas to the first heat exchange unit 30 through the high-temperature purified gas outlet 402.

[0045] As another alternative embodiment, the system further includes a second heat exchange unit 50. As Figure 1As shown in the figure, the second heat exchange unit 50 includes a cold air inlet 501, a hot air outlet 502, a medium-temperature purified gas inlet 503, and a low-temperature purified gas outlet 504. Among them, the medium-temperature purified gas inlet 503 is connected to the medium-temperature purified gas outlet 302 of the first heat exchange unit 30 through a pipeline, the low-temperature purified gas outlet 504 is connected to the chimney 60 through a pipeline, and the hot air outlet 502 is connected to the drying gas inlet 120 of the drying cavity 110 through a hot air pipeline HL, so that the hot air formed after heat exchange of the cold air entering through the cold air inlet 501 is provided into the drying cavity 110 through the hot air pipeline HL.

[0046] As another alternative embodiment, the VOCs gas pipeline L is provided with a first VOCs gas pipeline L1 and a second VOCs gas pipeline L2. The first VOCs gas pipeline L1 is connected to the cold VOCs gas inlet 303 of the first heat exchange unit 30, so as to provide 60% - 90% of the total amount of VOCs gas discharged from the drying cavity 110 into the first heat exchange unit 30 for heat exchange. The second VOCs gas pipeline L2 is connected to the drying gas inlet 120 of the drying cavity 110, so as to return 10% - 40% of the total amount of hot VOCs gas to the drying cavity 110 for recycling.

[0047] In this non-limiting embodiment, a first safety fan F1 for introducing VOCs gas into the filter 20 is provided on the pipeline between the drying production chamber 10 and the filter 20, and a second safety fan F2 for introducing VOCs gas into the processing chamber 420 is provided on the pipeline between the heating chamber 410 and the processing chamber 420. Both the first safety fan F1 and the second safety fan F2 are variable-frequency controlled fans, so as to ensure the operation safety of the whole system.

[0048] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0049] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention. For example, the first or second heat exchanger can adopt a heat pipe heat exchanger or a shell-and-tube heat exchanger.

Claims

1. A regenerative catalytic combustion waste heat utilization system for VOCs, comprising: Drying production chamber, the drying production chamber includes a drying cavity, one end of the drying cavity is provided with a drying gas inlet, and the other end of the drying cavity is provided with a VOC gas collection port, characterized in that: the VOC regenerative catalytic combustion waste heat utilization system further includes a first heat exchange unit and a regenerative catalytic combustion unit, wherein, The first heat exchange unit is provided with a high-temperature purified gas inlet, a medium-temperature purified gas outlet, a cold VOC gas inlet, and a hot VOC gas outlet. Among them, the medium-temperature purified gas outlet is connected to a chimney, and the cold VOC gas inlet is connected to the VOC waste gas collection port of the drying cavity through a pipeline, so that the cold VOC gas enters the first heat exchange unit for heat exchange to form hot VOC gas; The regenerative catalytic combustion unit includes a hot VOC gas inlet and a high-temperature purified gas outlet. Among them, the hot VOC gas inlet is connected to the hot VOC gas outlet of the first heat exchange unit through a pipeline, and the high-temperature purified gas outlet is connected to the high-temperature purified gas inlet of the first heat exchange unit through a pipeline, so that the high-temperature purified gas generated after catalytic combustion of VOC gas enters the first heat exchange unit to exchange heat with the cold VOC gas, It further includes a filter connected between the drying production chamber and the first heat exchange unit. Among them, the filter is provided with a filter inlet and a filter outlet. The filter inlet is connected to the VOC gas collection port of the drying production chamber through a pipeline, and the filter outlet is connected to the cold VOC gas inlet of the first heat exchange unit through a VOC gas pipeline to filter out the particles in the VOC gas generated by the drying production chamber and transport them to the first heat exchange unit, The first heat exchange unit includes: a housing, a first side longitudinal partition, a first intermediate longitudinal partition, a second intermediate longitudinal partition, and a second side longitudinal partition that are sequentially arranged in the inner cavity of the housing along the transverse direction of the housing, a first chamber formed between a side wall of the housing and the first side longitudinal partition, a first ventilation chamber formed between the first side longitudinal partition and the first intermediate longitudinal partition, an intermediate chamber formed between the first intermediate longitudinal partition and the second intermediate longitudinal partition, a second ventilation chamber formed between the second intermediate longitudinal partition and the second side longitudinal partition, a second chamber formed between another side wall of the housing and the second side longitudinal partition, a first transverse partition arranged in the first chamber and horizontally extending from the center of a side wall of the housing to the first side longitudinal partition, an intermediate transverse partition arranged in the intermediate chamber and horizontally extending from the center of the first intermediate longitudinal partition to the second intermediate longitudinal partition, and a second transverse partition arranged in the second chamber and horizontally extending from the center of the second side longitudinal partition to another side wall of the housing, wherein the first transverse partition divides the first chamber into a first upper gas chamber and a first lower gas chamber from top to bottom, the intermediate transverse partition divides the intermediate chamber into an intermediate upper gas chamber and an intermediate lower gas chamber from top to bottom, the second transverse partition divides the second chamber into a second upper gas chamber and a second lower gas chamber from top to bottom, a first plate fin heat exchanger is arranged in the first ventilation chamber, a second plate fin heat exchanger is arranged in the second ventilation chamber, the cold VOCs gas inlet is arranged on the outer side wall of the first upper gas chamber, the hot VOCs gas outlet is arranged on the outer side wall of the second upper gas chamber, the high-temperature purified gas inlet is arranged on the outer side wall of the second lower gas chamber, and the medium-temperature purified gas outlet is arranged on the outer side wall of the first lower gas chamber. The first plate fin heat exchanger and the second plate fin heat exchanger respectively include at least two rows of first fluid heat exchange tubes and at least two rows of second fluid heat exchange tubes, wherein the at least two rows of first fluid heat exchange tubes and the at least two rows of second fluid heat exchange tubes are cross-layered with each other, each row of first fluid heat exchange tubes and each row of second fluid heat exchange tubes respectively include at least four finned smooth tubes, each row of first fluid heat exchange tubes of the first plate fin heat exchanger extends obliquely downward from the first side longitudinal partition at the first upper gas chamber to the first intermediate longitudinal partition of the intermediate lower gas chamber, each row of first fluid heat exchange tubes of the second plate fin heat exchanger extends obliquely upward from the second intermediate longitudinal partition of the intermediate lower gas chamber to the second side longitudinal partition of the second upper gas chamber, each row of second fluid heat exchange tubes of the first plate fin heat exchanger extends obliquely upward from the first side longitudinal partition at the first lower gas chamber to the first intermediate longitudinal partition of the intermediate upper gas chamber, and each row of second fluid heat exchange tubes of the second plate fin heat exchanger extends obliquely downward from the second intermediate longitudinal partition of the intermediate upper gas chamber to the second side longitudinal partition of the second lower gas chamber. The first side longitudinal partition board is provided with through holes communicating with the heads of each row of first fluid heat exchange tubes and each row of second fluid heat exchange tubes of the first plate fin heat exchanger, the first intermediate longitudinal partition board is provided with through holes communicating with the tails of each row of first fluid heat exchange tubes and each row of second fluid heat exchange tubes of the first plate fin heat exchanger, the second intermediate longitudinal partition board is provided with through holes communicating with the heads of each row of first fluid heat exchange tubes and each row of second fluid heat exchange tubes of the second plate fin heat exchanger, and the second side longitudinal partition board is provided with through holes communicating with the tails of each row of first fluid heat exchange tubes and each row of second fluid heat exchange tubes of the second plate fin heat exchanger. The regenerative catalytic combustion unit includes: a heating chamber, a catalytic chamber, and a regenerative chamber connected in sequence through pipelines. Among them, the heating chamber is used for reheating and heating the hot VOCs gas entering the regenerative catalytic combustion unit. The catalytic chamber is used for catalytic oxidation of the VOCs gas heated by the catalyst to decompose and form high-temperature purified gas. The regenerative chamber is used for collecting the heat of the high-temperature purified gas to preheat the subsequent VOCs gas entering the regenerative catalytic combustion unit. The heating medium of the heating chamber is natural gas. The catalyst in the catalytic chamber is Pd.

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