An artificial board industry VOCs waste gas purification system and method

Abstract

The present invention discloses a purification system and method for VOCs waste gas in the wood-based panel industry. The system includes a first purification unit, which is used to purify the first path of waste gas distributed by the first distributor through in-furnace combustion; a second purification unit, which is arranged in parallel with respect to the first purification unit. The second purification unit includes a heat exchange mechanism, a mixed air mechanism, and a regenerative catalytic combustion mechanism. Aiming at the limitations in the prior art that the purification efficiency is low when using traditional simple methods for waste gas treatment in the wood-based panel industry, and it is difficult to achieve the balance of waste gas volume when using the traditional boiler combustion method, the system provides a treatment system that combines boiler combustion, in-furnace heat exchange, off-furnace catalytic combustion, and boiler flue gas purification system, which can achieve the deep purification and stable compliance of low-concentration VOCs waste gas in wood-based panel enterprises. Through the waste gas dynamic balance adjustment technology, the dynamic balance adjustment of the waste gas volume of the enterprise can be realized, and the adaptability of the system to the fluctuation of waste gas parameters can be significantly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of waste gas treatment in the wood-based panel industry, and particularly to a VOCs waste gas purification system and method for the wood-based panel industry. Background Art

[0002] Adhesives are used in the production process of wood-based panels, mainly including urea-formaldehyde resin adhesive, phenolic resin adhesive, and melamine adhesive. A large amount of low-concentration VOCs waste gas is released during processes such as glue making, glue coating, cold pressing, and hot pressing, and its main component is formaldehyde. Formaldehyde is highly irritating and strongly irritates the eyes, nose, throat and other organs of workshop workers, directly endangering physical health and also seriously affecting the air quality of the environment around the enterprise. Therefore, it is of great significance to effectively control VOCs waste gas pollution in the wood-based panel industry.

[0003] At present, the concentration of VOCs in the waste gas of the wood-based panel industry is low, and simple methods such as activated carbon adsorption, liquid absorption method, and UV photocatalysis are mostly used for treatment. It is relatively difficult for the above methods to meet the standards stably, and it is impossible to achieve the deep purification effect of organic waste gas. At the same time, secondary pollution is likely to occur. As an efficient treatment method, the combustion method has the advantage of thorough purification of VOCs, but the investment and operation costs of VOCs special combustion equipment are high, especially the treatment cost for low-concentration VOCs is relatively high. The published invention patent CN107726339 discloses a formaldehyde waste gas treatment system, which is characterized in that: the formaldehyde generated during the glue-making chemical reaction in the reaction kettle is connected to a fan through a pipeline, the outlet of the fan is connected to a secondary fan through a pipeline, the air outlet of the secondary fan is connected to a pipeline leading to the boiler, and branch pipelines are welded on the pipeline extending into the furnace. The number of branch pipelines is at least six or more, and the branch pipelines are inserted into the furnace at a certain angle. It provides an idea of using a boiler as a VOCs combustion device, but the drawback is that the amount of VOCs waste gas generated during the production process of wood-based panel enterprises is much larger than the demand of the boiler secondary fan, and this combustion treatment method cannot treat all the waste gas of wood-based panel enterprises. Summary of the Invention

[0004] The present invention provides a VOCs waste gas purification system and method for the wood-based panel industry. Through the coupling of boiler combustion and catalytic combustion outside the furnace, as well as the system waste gas dynamic balance adjustment technology, the deep purification of VOCs in the wood-based panel industry is realized.

[0005] The present invention provides the following solutions:

[0006] A VOCs waste gas purification system for the wood-based panel industry, comprising:

[0007] A first purification unit, which is used for purifying the first-way waste gas distributed by the first distributor through in-furnace combustion;

[0008] The second purification unit is arranged in parallel with respect to the first purification unit; the second purification unit includes a heat exchange mechanism, a mixed air mechanism, and a regenerative catalytic combustion mechanism; the heat exchange mechanism is used to heat the second path of exhaust gas distributed by the second distribution part; the mixed air mechanism is used to mix the third path of exhaust gas distributed by the third distribution part and the heated second path of exhaust gas output by the heat exchange mechanism to obtain mixed exhaust gas; the regenerative catalytic combustion mechanism is used to perform off-furnace catalytic combustion purification on the mixed exhaust gas output by the mixed air mechanism.

[0009] Preferably: the first purification unit includes a combustion boiler, and the heat exchange mechanism is located inside the combustion boiler and closely adheres to the inner wall of the furnace of the combustion boiler.

[0010] Preferably: the heat exchange mechanism includes a refractory brick layer and heat exchange tubes; a VOCs catalyst layer is loaded on the inner wall of the heat exchange tubes.

[0011] Preferably: the heat exchange tubes are made of 20G seamless steel pipes or made of ceramic tubes or made of light tube water walls or have a modular water wall structure or are made of circular hole refractory bricks 16 stacked.

[0012] Preferably: the regenerative catalytic combustion mechanism includes a honeycomb VOCs catalyst, a ceramic honeycomb regenerator, and a heat preservation layer; the working temperature of the honeycomb VOCs catalyst is 50 - 350 °C, and the space velocity is 20000 - 30000 h -1 .

[0013] Preferably: it further includes a plurality of exhaust gas conveying pipelines, the inlet ends of each exhaust gas conveying pipeline are respectively connected to a set of wood-based panel exhaust gas generating mechanisms, and each exhaust gas conveying pipeline is connected to the inlet end of the same first booster fan; the inlet ends of the first distribution part, the second distribution part, and the third distribution part are all connected to the outlet end of the first booster fan; regulating valves are arranged on each exhaust gas conveying pipeline, on the pipeline included in the first distribution part, on the pipeline included in the second distribution part, and on the pipeline included in the third distribution part.

[0014] Preferably: it further includes a third purification unit, and the third purification unit includes a dust removal mechanism, a desulfurization and denitration mechanism, a boiler induced draft fan, and a chimney connected in sequence, and the outlet ends of the first purification unit and the second purification unit are both connected to the dust removal mechanism.

[0015] Preferably: it further includes a high-temperature gas guiding part, one end of the pipeline of the high-temperature gas guiding part is connected to the inlet end of the heat exchange mechanism; the other end of the pipeline of the high-temperature gas guiding part is connected to the upstream pipeline and / or the downstream pipeline of the dust removal mechanism.

[0016] A method for purifying VOCs waste gas in the wood-based panel industry, the method comprising:

[0017] Obtain the total amount of waste gas generated by each wood-based panel waste gas generating mechanism, compare the total amount of waste gas with the preset waste gas treatment capacity of the first purification unit to obtain a first comparison result, and determine the distribution air volume of the first distribution part, the second distribution part, and the third distribution part according to the first comparison result;

[0018] If the first comparison result is that the total amount of waste gas is not greater than the waste gas treatment capacity, determine that the distribution air volume of the first distribution part is the total amount of waste gas, and the distribution air volumes of the second distribution part and the third distribution part are both zero;

[0019] If the first comparison result is that the total amount of waste gas is greater than the waste gas treatment capacity, determine that the distribution air volume of the first distribution part is the waste gas treatment capacity; obtain the real-time temperature of the waste gas generated by each wood-based panel waste gas generating mechanism, compare the real-time temperature with the working temperature of the regenerative catalytic combustion mechanism to obtain a second comparison result, and determine the distribution air volume of the second distribution part and the third distribution part according to the second comparison result, so that the temperature of the mixed waste gas output by the air mixing mechanism meets the requirements of the working temperature of the regenerative catalytic combustion mechanism.

[0020] Preferably: the distribution air volume of the second distribution part is the total amount of waste gas minus the waste gas treatment capacity, and the distribution air volume of the third distribution part is zero; the temperature of the mixed waste gas is lower than the working temperature of the regenerative catalytic combustion mechanism;

[0021] Guide the high-temperature gas treated upstream and / or downstream of the dust removal mechanism to the heat exchange mechanism through the high-temperature gas guiding part.

[0022] According to the specific embodiments provided by the present invention, the following technical effects are disclosed by the present invention:

[0023] Through the present invention, a VOCs waste gas purification system and method in the wood-based panel industry can be realized. In one implementation, the system may include a first purification unit for purifying the first path of waste gas distributed by the first distribution part by in-furnace combustion; a second purification unit, the second purification unit being arranged in parallel with respect to the first purification unit; the second purification unit including a heat exchange mechanism, an air mixing mechanism, and a regenerative catalytic combustion mechanism; the heat exchange mechanism being used for heating the second path of waste gas distributed by the second distribution part; the air mixing mechanism being used for mixing the third path of waste gas distributed by the third distribution part and the heated second path of waste gas output by the heat exchange mechanism to obtain a mixed waste gas; the regenerative catalytic combustion mechanism being used for purifying the mixed waste gas output by the air mixing mechanism by out-of-furnace catalytic combustion.

[0024] The beneficial effects of the present invention include:

[0025] 1. Compared with the traditional VOCs waste gas purification process in the wood-based panel industry, through the coupling of boiler combustion and off-boiler catalytic combustion in this system, the VOCs waste gas can achieve deep purification through boiler combustion (once), off-boiler catalytic combustion (once), and boiler flue gas purification system (twice). It can achieve stable compliance for low-concentration VOCs waste gas in wood-based panel enterprises, solve the impact of gaseous pollutants such as low-concentration formaldehyde on human health that has long existed in wood-based panel enterprises, completely eliminate the serious impact of such irritating environmental odors that have long existed in enterprises on workers and nearby residents, and reduce public complaints and reports.

[0026] 2. Compared with the traditional VOCs combustion treatment process in the wood-based panel industry, based on boiler combustion technology, this system combines in-furnace heat exchange coupling off-boiler catalytic combustion technology and waste gas dynamic balance adjustment technology, and can achieve dynamic balance adjustment of the enterprise's waste gas volume. When the waste gas generation mechanism of the wood-based panel stops, the pipeline regulating valve can be dynamically closed to reduce the waste gas volume processed by the system; the VOCs waste gas can also be preferentially and gradiently utilized in the boiler as combustion-supporting gas for combustion, and then enter the off-boiler catalytic combustion device for treatment. This process has strong adaptability to fluctuations in waste gas parameters (such as volume, concentration, etc.), and can significantly increase the waste gas treatment volume of enterprises for VOCs.

[0027] 3. The in-furnace heat exchange coupling off-boiler catalytic combustion technology proposed by this system provides a low-cost VOCs catalytic combustion technology. By heating part of the waste gas in the boiler to increase the temperature and then mixing it with the VOCs waste gas to be treated, compared with the traditional VOCs catalytic combustion process, it can significantly reduce investment and operating costs. In the mentioned process, after using part of the high-temperature boiler flue gas for heat recovery in the boiler and then mixing it with the waste gas to be treated and entering the catalytic combustion device; this process route can make full use of the waste heat of the flue gas, reduce the waste gas heating cost of the catalytic combustion treatment device, and at the same time can appropriately reduce the oxygen content of the waste gas to be treated, and return it to the boiler waste gas purification unit, which has little impact on the reference oxygen content conversion concentration of pollutants discharged from the boiler waste gas purification unit.

[0028] 4. The various structural heat exchange devices proposed by this system, by being built into the boiler and closely attached to the furnace wall, can extend the service life of the refractory material on the inner wall of the high-temperature area in the boiler furnace.

[0029] 5. The regenerative catalytic combustion device proposed by this system, by arranging annular ceramic honeycomb regenerators in the device, compared with the traditional catalytic combustion device, can significantly reduce heat loss and treatment costs.

[0030] Of course, it is not necessary for any product implementing the present invention to achieve all the above-mentioned advantages simultaneously. Brief Description of the Drawings

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for use in the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0032] Figure 1 is a schematic structural diagram of a VOCs waste gas purification system for the wood-based panel industry provided by an embodiment of the present invention;

[0033] Figure 2 is another schematic structural diagram of a VOCs waste gas purification system for the wood-based panel industry provided by an embodiment of the present invention;

[0034] Figure 3 is a first schematic structural diagram of a heat exchange mechanism provided by an embodiment of the present invention;

[0035] Figure 4 is a second schematic structural diagram of a heat exchange mechanism provided by an embodiment of the present invention;

[0036] Figure 5 is a third schematic structural diagram of a heat exchange mechanism provided by an embodiment of the present invention;

[0037] Figure 6 is a fourth schematic structural diagram of a heat exchange mechanism provided by an embodiment of the present invention;

[0038] Figure 7 is a schematic structural diagram of a regenerative catalytic combustion mechanism provided by an embodiment of the present invention.

[0039] In the figure: 1 - wood-based panel waste gas generation mechanism, 2 - pipeline regulating valve, 31 - first booster fan, 32 - second booster fan, 41 - boiler primary fan, 42 - boiler secondary fan, 5 - combustion boiler, 6 - dust removal mechanism, 7 - desulfurization and denitrification mechanism, 8 - boiler induced draft fan, 9 - chimney, 10 - heat exchange mechanism, 11 - air mixing mechanism, 12 - regenerative catalytic combustion mechanism, 13 - refractory brick layer, 14 - heat exchange tube, 15 - inner wall of the furnace, 16 - perforated refractory brick, 17 - perforated channel, 18 - waste gas inlet, 19 - honeycomb VOCs catalyst, 20 - ceramic honeycomb regenerator, 21 - waste gas outlet, 22 - insulation layer. Detailed implementation manners

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present invention. Embodiment

[0041] Refer to Figure 1 , a VOCs waste gas purification system provided by an embodiment of the present invention. As Figure 1 shown, the system includes a first purification unit, and the first purification unit is used to purify the first path of waste gas distributed by the first distribution part Ⅰ by in-furnace combustion;

[0042] A second purification unit, the second purification unit is arranged in parallel with respect to the first purification unit; the second purification unit includes a heat exchange mechanism 10, a mixed air mechanism 11 and a regenerative catalytic combustion mechanism 12; the heat exchange mechanism 10 is used to heat the second path of waste gas distributed by the second distribution part Ⅱ; the mixed air mechanism 11 is used to mix the third path of waste gas distributed by the third distribution part Ⅲ and the heated second path of waste gas output by the heat exchange mechanism 10 to obtain mixed waste gas; the regenerative catalytic combustion mechanism 12 is used to purify the mixed waste gas output by the mixed air mechanism 11 by out-of-furnace catalytic combustion.

[0043] Furthermore, the first purification unit includes a combustion boiler 5, and the heat exchange mechanism 10 is located in the combustion boiler 5 and closely adheres to the inner wall 15 of the furnace chamber of the combustion boiler 5. The heat exchange mechanism is arranged in the combustion boiler, and the preheat of the boiler can be used to realize the temperature rise of the waste gas, without the need to provide additional heating equipment. Specifically, the heat exchange mechanism 10 includes a refractory brick layer 13 and heat exchange tubes 14. The inner wall of the heat exchange tube 14 is loaded with a VOCs catalyst layer. The heat exchange tube 14 can be made of 20G seamless steel pipe or made of ceramic tube or made of light tube water-cooled wall or has a pattern water-cooled wall structure or is made of circular hole refractory bricks 16 stacked.

[0044] Furthermore, the regenerative catalytic combustion mechanism 12 includes a honeycomb VOCs catalyst 19, a ceramic honeycomb regenerator 20 and a heat preservation layer 22. The working temperature of the honeycomb VOCs catalyst is 50 - 350 °C, and the space velocity is 20000 - 30000 h -1 .

[0045] Furthermore, it also includes a plurality of waste gas delivery pipelines, each of which has an air inlet connected to a set of artificial board waste gas generating mechanism 1, and each of which is connected to the inlet end of the same first booster fan 31; the inlet ends of the first distribution part I, the second distribution part II, and the third distribution part III are connected to the outlet end of the first booster fan 31; each of the waste gas delivery pipelines, the pipelines included in the first distribution part, the pipelines included in the second distribution part, and the pipelines included in the third distribution part are provided with a regulating valve 2. It also includes a third purification unit, which includes a dust removal mechanism 6, a desulfurization and denitrification mechanism 7, a boiler induced draft fan 8, and a chimney 9 connected in sequence, and the outlet end of the first purification unit and the outlet end of the second purification unit are connected to the dust removal mechanism. It also includes high-temperature gas guide parts IV and V, one end of the pipeline of the high-temperature gas guide parts IV and V is connected to the inlet end of the heat exchange mechanism 10; the other end of the pipeline of the high-temperature gas guide part is connected to the upstream pipeline of the dust removal mechanism 6 and / or the downstream pipeline of the dust removal mechanism 6. When the inner wall of the heat exchange tube is loaded with VOCs catalyst, the second exhaust gas can catalytically purify part of VOCs when passing through the heat exchange device. The second exhaust gas entering the heat exchange mechanism for heat exchange can also transport the high-temperature exhaust gas before or after the dust removal mechanism in the boiler exhaust gas purification unit to the heat exchange mechanism through the exhaust gas distribution pipeline for heat exchange. After the exhaust gas after heat exchange is mixed with the third exhaust gas in the air mixing mechanism, the exhaust gas temperature meets the working temperature requirements of the catalyst of the heat storage catalytic combustion mechanism.

[0046] The system provided in the present application may include an exhaust gas conveying pipeline, an exhaust gas purification dynamic distribution unit composed of a first distribution part, a second distribution part and a third distribution part, a boiler combustion purification unit (first purification unit), an in-furnace heat exchange coupled with an outside-furnace catalytic combustion unit (second purification unit), a boiler exhaust gas purification unit (third purification unit), and also includes any necessary pipelines, boosters, valves and / or control systems for selectively guiding the VOCs exhaust gas generated by the artificial board exhaust gas generating mechanism through the booster, the first distribution part, the second distribution part and the third distribution part to be output to the first purification unit and / or the second purification unit in a dynamically balanced manner.

[0047] The exhaust gas delivery unit includes multiple exhaust gas delivery pipelines, multiple exhaust gas pipeline regulating valves, and multiple booster fans. The inlets of the multiple exhaust gas delivery pipelines are connected to the gas collecting port of the artificial board exhaust gas generating mechanism, the multiple exhaust gas delivery pipelines are respectively provided with regulating valves, and the collection pipe of the exhaust gas delivery pipeline is connected to the booster fan 31.

[0048] The exhaust gas purification dynamic distribution unit includes a first distribution part, a second distribution part, a third distribution part (I, II, III), and a plurality of pipeline regulating valves. The inlets of the first distribution part, the second distribution part, and the third distribution part (I, II, III) are connected to the outlet of the booster fan, and regulating valves are respectively arranged on the plurality of exhaust gas distribution pipelines.

[0049] The boiler combustion purification unit (the first purification unit) includes a boiler, a primary fan and a secondary fan.

[0050] The heat exchange in the furnace is coupled with the catalytic combustion unit outside the furnace (the second purification unit), including a heat exchange mechanism, an air mixing mechanism, and a regenerative catalytic combustion mechanism. Among them, the heat exchange mechanism can be built into the boiler close to the furnace wall, the outlet of the heat exchange mechanism and the inlet of the air mixing mechanism are connected by an exhaust gas pipeline, the outlet of the air mixing mechanism is connected to the inlet of the regenerative catalytic combustion mechanism, and the outlet of the regenerative catalytic combustion mechanism is connected to the inlet of the boiler exhaust gas purification unit by a pipeline, or the outlet is directly discharged to the atmosphere.

[0051] The boiler exhaust gas purification unit (the third purification unit) includes a dust removal mechanism, a desulfurization and denitrification device, a boiler induced draft fan, and a chimney.

[0052] The outlets of the first distribution part, the second distribution part and the third distribution part (Ⅰ, Ⅱ, Ⅲ) are respectively connected to the inlet of the boiler primary fan, the inlet of the boiler secondary fan, the inlet of the heat exchange mechanism and the inlet of the air mixing mechanism.

[0053] like Figure 2 As shown, exhaust gas interfaces are arranged before and after the dust removal mechanism, and the exhaust gas interfaces are connected to the inlet of the heat exchange mechanism through a high-temperature gas guide.

[0054] like Figure 3 , Figure 4 , Figure 5 , Figure 6 As shown, the heat exchange mechanism may include a refractory brick layer and a heat exchange tube.

[0055] The material of the heat exchange tube is 20G seamless steel tube or ceramic tube, and the diameter of the heat exchange tube is 20-80mm.

[0056] The heat exchange tubes can adopt a bare tube water-cooled wall or a patterned water-cooled wall structure.

[0057] The heat exchange tubes can be stacked with round hole refractory bricks 16.

[0058] The heat exchange tubes can be composed of 2-4 rows.

[0059] The inner wall of the heat exchange tube is loaded with VOCs catalyst.

[0060] like Figure 7As shown in the figure, the regenerative catalytic combustion mechanism may include an exhaust gas inlet 18, a ceramic honeycomb regenerator 20, a honeycomb VOCs catalyst 19, a heat insulation layer 22, and an exhaust gas outlet 21. The working temperature of the honeycomb VOCs catalyst 19 is 50 - 350 °C, and the space velocity is 20,000 - 30,000 h -1 .

[0061] The process for purifying VOCs exhaust gas in the wood-based panel industry using this system includes the following steps:

[0062] The VOCs exhaust gas generated by the wood-based panel exhaust gas generation mechanism 1 is transported to the exhaust gas purification dynamic distribution unit by the first booster fan 31. The exhaust gas is divided into three paths and enters the subsequent boiler exhaust gas purification unit and the in-furnace heat exchange and out-of-furnace catalytic combustion unit. Among them, the first path of exhaust gas is connected to the inlets of the primary boiler fan and the secondary boiler fan through the first distribution part Ⅰ, and this path of exhaust gas enters the boiler for combustion purification; one path of exhaust gas enters the heat exchange mechanism built in the boiler through the first distribution part Ⅱ, and after heat exchange, it enters the mixing mechanism together with the third path of exhaust gas through the third distribution part Ⅲ and is mixed, and then enters the regenerative catalytic combustion mechanism for purification treatment. The working process of the regenerative catalytic combustion mechanism is that the exhaust gas enters the ceramic honeycomb regenerator 20 through the middle exhaust gas inlet 18, then enters the bed layer of the honeycomb VOCs catalyst 19 for catalytic combustion, and the purified exhaust gas flows out from the side ceramic honeycomb regenerator and is discharged through the exhaust gas outlet 21. The exhaust gas after catalytic combustion treatment enters the boiler exhaust gas purification unit again, or is directly discharged.

[0063] By adjusting the multiple regulating valves in the exhaust gas purification dynamic distribution unit, the exhaust gas flow rates of each exhaust gas distribution part (Ⅰ, Ⅱ, Ⅲ) are reasonably distributed. Among them, priority is given to ensuring that the first path of exhaust gas enters the boiler through the primary boiler fan and the secondary boiler fan for combustion treatment; then, by reasonably distributing the exhaust gas flow rates of the second path and the third path of exhaust gas, it is ensured that after the second path of exhaust gas and the third path of exhaust gas after heat exchange in the heat exchange mechanism are mixed in the mixing mechanism, the exhaust gas temperature meets the catalyst working temperature requirements of the regenerative catalytic combustion mechanism.

[0064] When the flow rate of the VOCs exhaust gas generated by the wood-based panel exhaust gas generation mechanism is small, by adjusting the multiple regulating valves in the exhaust gas purification dynamic distribution unit, priority is given to considering passing all the exhaust gas through the primary boiler fan and the secondary boiler fan and entering the boiler for combustion treatment.

[0065] When the inner wall of the heat exchange tube is loaded with a VOCs catalyst, when the second path of exhaust gas passes through the heat exchange mechanism, part of the VOCs can be catalytically purified.

[0066] The second path of waste gas entering the heat exchange mechanism for heat exchange can also transport the high-temperature waste gas before or after the dust removal mechanism in the boiler waste gas purification unit to the heat exchange mechanism for heat exchange through the high-temperature gas guiding parts Ⅳ and Ⅴ. After the heat-exchanged waste gas is mixed with the third path of waste gas in the air mixing mechanism, the temperature of the waste gas meets the catalyst working temperature requirements of the regenerative catalytic combustion mechanism.

[0067] Using a VOCs waste gas purification system for the wood-based panel industry of the present invention (such as Figure 1 ), the heat exchange mechanism adopts Figure 3 a structure. The VOCs waste gas generated by the wood-based panel waste gas generation mechanism is transported to the waste gas purification dynamic distribution unit by a booster fan, and the waste gas is divided into three paths and enters the subsequent boiler waste gas purification unit and the in-furnace heat exchange coupled with the out-of-furnace catalytic combustion unit. After catalytic combustion, the waste gas enters the boiler waste gas purification unit. The system processes 30,000 m³ / h of VOCs waste gas, the catalyst operating temperature is 200 °C, and the space velocity is 30,000 h -1 , and the formaldehyde concentration in the waste gas at the outlet of the boiler waste gas and the outlet of the regenerative catalytic combustion mechanism is lower than 0.5 mg / Nm 3 .

[0068] Using a VOCs waste gas purification system for the wood-based panel industry of the present invention (such as Figure 2 ), the heat exchange mechanism adopts Figure 6 a structure. The VOCs waste gas generated by the wood-based panel waste gas generation mechanism is transported to the waste gas purification dynamic distribution unit by a booster fan, and the waste gas is divided into two paths and enters the subsequent boiler waste gas purification unit and the in-furnace heat exchange coupled with the out-of-furnace catalytic combustion unit. After catalytic combustion, the waste gas enters the boiler waste gas purification unit. Part of the high-temperature waste gas after the dust removal mechanism in the boiler waste gas purification unit is transported to the heat exchange mechanism through the high-temperature gas guiding part for heat exchange, and the heat-exchanged waste gas enters the air mixing mechanism. The system processes 20,000 m³ / h of VOCs waste gas, the catalyst operating temperature is 250 °C, and the space velocity is 30,000 h -1 , and the formaldehyde concentration in the waste gas at the outlet of the boiler waste gas and the outlet of the regenerative catalytic combustion mechanism is lower than 0.5 mg / Nm 3 .

[0069] The embodiment of the present application can also provide a method for purifying VOCs waste gas in the wood-based panel industry, and the method includes:

[0070] Obtain the total amount of waste gas generated by each set of wood-based panel waste gas generation mechanisms, compare the total amount of waste gas with the preset waste gas treatment amount of the first purification unit to obtain a first comparison result, and determine the distribution air volume of the first distribution part, the second distribution part, and the third distribution part according to the first comparison result;

[0071] When the first comparison result is that the total amount of waste gas is not greater than the waste gas treatment capacity, it is determined that the air distribution volume of the first distribution unit is the total amount of waste gas, and the air distribution volumes of the second distribution unit and the third distribution unit are both zero;

[0072] When the first comparison result is that the total amount of waste gas is greater than the waste gas treatment capacity, it is determined that the air distribution volume of the first distribution unit is the waste gas treatment capacity; the real-time temperature of the waste gas generated by each set of wood-based panel waste gas generation mechanisms is obtained, and the real-time temperature is compared with the working temperature of the regenerative catalytic combustion mechanism to obtain a second comparison result, and the air distribution volumes of the second distribution unit and the third distribution unit are determined according to the second comparison result, so that the temperature of the mixed waste gas output by the air mixing mechanism meets the requirements of the working temperature of the regenerative catalytic combustion mechanism.

[0073] Further, when the temperature of the waste gas is relatively low and still cannot reach the working temperature requirement of the regenerative catalytic combustion mechanism after all the remaining gas is heat-exchanged through the heat exchange mechanism, the air distribution volume of the second distribution unit is the total amount of waste gas minus the waste gas treatment capacity, and the air distribution volume of the third distribution unit is zero; the temperature of the mixed waste gas is lower than the working temperature of the regenerative catalytic combustion mechanism;

[0074] The high-temperature gas treated upstream and / or downstream of the dust removal mechanism is guided into the heat exchange mechanism through the high-temperature gas guiding part.

[0075] In summary, for the VOCs waste gas purification system in the wood-based panel industry provided by the present application, aiming at the limitations of the existing traditional and simple methods with low purification efficiency and difficulty in achieving waste gas volume balance by using the traditional boiler combustion method in the waste gas treatment of the wood-based panel industry, the system provided by the present invention can achieve deep purification and stable compliance of low-concentration VOCs waste gas in wood-based panel enterprises through boiler combustion, in-furnace heat exchange, coupled with out-of-furnace catalytic combustion, and the boiler flue gas purification system. Through the waste gas dynamic balance adjustment technology, the dynamic balance adjustment of the waste gas volume of the enterprise can be realized, and the adaptability of the system to the waste gas parameter fluctuation can be significantly improved.

[0076] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising said element.

[0077] The above are only the preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are all included within the scope of protection of the present invention.

Claims

1. An artificial board industry VOCs waste gas purification system, characterized in that, Including: A first purification unit for purifying the first waste gas distributed by the first distribution part through in-furnace combustion; A second purification unit, which is arranged in parallel with respect to the first purification unit; the second purification unit includes a heat exchange mechanism, a mixed air mechanism, and a regenerative catalytic combustion mechanism; It further includes a plurality of waste gas transmission pipelines. The inlet ends of each waste gas transmission pipeline are respectively connected to a set of wood-based panel waste gas generation mechanisms, and each waste gas transmission pipeline is connected to the inlet end of the same first booster fan; the inlet ends of the first distribution part, the second distribution part, and the third distribution part are all connected to the outlet end of the first booster fan; regulating valves are arranged on each waste gas transmission pipeline, on the pipeline included in the first distribution part, on the pipeline included in the second distribution part, and on the pipeline included in the third distribution part; The heat exchange mechanism is used for heating the second waste gas distributed by the second distribution part; the mixed air mechanism is used for mixing the third waste gas distributed by the third distribution part and the heated second waste gas output by the heat exchange mechanism to obtain mixed waste gas; the regenerative catalytic combustion mechanism is used for purifying the mixed waste gas output by the mixed air mechanism through out-of-furnace catalytic combustion; The heat exchange mechanism includes a refractory brick layer and heat exchange tubes; a VOCs catalyst layer is loaded on the inner wall of the heat exchange tubes; the heat exchange tubes are made of 20G seamless steel pipes or ceramic tubes or light tube water walls or have a modular water wall structure or are built by stacking round-hole refractory bricks.

2. The VOCs waste gas purification system for the wood-based panel industry according to claim 1, characterized in that, The first purification unit includes a combustion boiler, and the heat exchange mechanism is located inside the combustion boiler and closely adheres to the inner wall of the furnace of the combustion boiler.

3. The VOCs waste gas purification system for the wood-based panel industry according to claim 1, wherein, The regenerative catalytic combustion mechanism includes a honeycomb VOCs catalyst, a ceramic honeycomb regenerator, and a thermal insulation layer; the working temperature of the honeycomb VOCs catalyst is 50 - 350 °C, and the space velocity is 20000 - 30000 h -1 .

4. The VOCs waste gas purification system for the wood-based panel industry according to claim 1, wherein, It further includes a third purification unit, which includes a dust removal mechanism, a desulfurization and denitration mechanism, a boiler induced draft fan, and a chimney connected in sequence. The outlet ends of the first purification unit and the second purification unit are both connected to the dust removal mechanism.

5. The VOCs waste gas purification system for the wood-based panel industry according to claim 4, characterized in that, It further includes a high-temperature gas guiding part, one end of the pipeline of the high-temperature gas guiding part is connected to the inlet end of the heat exchange mechanism; the other end of the pipeline of the high-temperature gas guiding part is connected to the upstream pipeline and / or the downstream pipeline of the dust removal mechanism.

6. A method for purifying VOCs waste gas in the wood-based panel industry, characterized in that, Applied to the wood-based panel industry VOCs waste gas purification system according to any one of claims 1-5; the first waste gas is connected to the inlets of the primary fan and the secondary fan of the boiler through the first distribution part, and this waste gas enters the boiler for combustion purification; one waste gas enters the heat exchange mechanism built in the boiler through the first distribution part for heat exchange, and after being mixed with the third waste gas entering the mixed air mechanism through the third distribution part, it enters the regenerative catalytic combustion mechanism for purification treatment; The method includes: Obtaining the total amount of waste gas generated by each set of wood-based panel waste gas generation mechanisms, comparing the total amount of waste gas with the preset waste gas treatment amount of the first purification unit to obtain a first comparison result, and determining the distribution air volume of the first distribution part, the second distribution part, and the third distribution part according to the first comparison result; When the first comparison result is that the total amount of waste gas is not greater than the waste gas treatment capacity, it is determined that the air distribution volume of the first distribution unit is the total amount of waste gas, and the air distribution volumes of the second distribution unit and the third distribution unit are both zero; When the first comparison result is that the total amount of waste gas is greater than the waste gas treatment capacity, it is determined that the air distribution volume of the first distribution unit is the waste gas treatment capacity; the real-time temperature of the waste gas generated by each set of wood-based panel waste gas generating mechanisms is obtained, and the real-time temperature is compared with the working temperature of the regenerative catalytic combustion mechanism to obtain a second comparison result, and the air distribution volumes of the second distribution unit and the third distribution unit are determined according to the second comparison result, so that the temperature of the mixed waste gas output by the air mixing mechanism meets the requirements of the working temperature of the regenerative catalytic combustion mechanism; When the inner wall of the heat exchange tube is loaded with a VOCs catalyst, when the second path of waste gas passes through the heat exchange mechanism, part of the VOCs can be catalytically purified.

7. The method for purifying VOCs waste gas in the wood-based panel industry according to claim 6, wherein, The air distribution volume of the second distribution unit is the total amount of waste gas minus the waste gas treatment capacity, and the air distribution volume of the third distribution unit is zero; the temperature of the mixed waste gas is lower than the working temperature of the regenerative catalytic combustion mechanism; The high-temperature gas treated upstream and / or downstream of the dust removal mechanism is guided into the heat exchange mechanism through the high-temperature gas guiding part.

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