CN108554150A - A kind of pre-heated catalytic combustion system of purifying volatile organic exhaust gas - Google Patents

Abstract

The invention discloses a preheating catalytic combustion system for purifying volatile organic waste gas, which mainly relates to the field of waste gas treatment, including a sequentially connected compression storage unit, an adsorption unit and a catalytic combustion unit, through which VOCs waste gas is processed. , which can not only ensure the purification efficiency, but also reduce the loss of heat energy, and is also conducive to the recovery of organic solvents, thereby greatly improving the economic benefits of VOCs waste gas treatment.

Description

A preheating catalytic combustion system for purifying volatile organic waste gas

technical field

The invention relates to the field of waste gas treatment, more specifically, it relates to a preheating catalytic combustion system for purifying volatile organic waste gas.

Background technique

Volatile organic compounds (Volatile organic compounds, VOCs) usually refer to organic compounds with a saturated vapor pressure greater than 133Pa at 25°C, and their main components are hydrocarbons, halogenated hydrocarbons, oxygen hydrocarbons, sulfur hydrocarbons, nitrogen hydrocarbons, aromatic hydrocarbons and polycyclic aromatic hydrocarbons. VOCs are a kind of commonly used reagents in the petrochemical industry, spray painting industry, paint production and processing industry, rubber production and processing industry, printing and dyeing industry, etc. The resulting VOCs exhaust gas usually has complex components and large changes in emission concentration. , not easily soluble in water, containing acid or alkali characteristics and difficult to handle.

At present, the conventional treatment methods for VOCs are: condensation method, which is mainly used to recover single-component gases with high concentration, high boiling point and small gas volume, and has a low recovery rate of exhaust gas from complex components; absorption method, which is mainly used for large volume, high Concentration and solubility of waste gas, but the treatment efficiency of waste gas with poor solubility is low; activated carbon adsorption method is suitable for low concentration and large volume of VOCs waste gas, activated carbon is easy to absorb and saturate, and the cost of replacing the adsorbent is expensive and the activated carbon after adsorption is saturated It needs to be treated as a kind of hazardous waste; the combustion method is mainly aimed at organic waste gas with high concentration and complex components. This method has simple process and high removal efficiency. The combination of adsorption and combustion is not only suitable for treating waste gas with different concentrations and components, but also has high removal efficiency.

And the traditional device for treating VOCs waste gas by the combination of adsorption and combustion has two operating modes: (1) direct exhaust type, which directly transports the desorbed organic waste gas to the heat exchanger and catalytic combustion chamber for combustion and degradation. Because the temperature of the catalytic combustion chamber is low at the beginning of the system start-up, some organic waste gas will generate harmful intermediate products due to incomplete combustion, or be directly discharged without combustion, and the heat energy in the exhaust gas is difficult to fully utilize; (2) Internal circulation type, The desorbed organic waste gas is combusted and circulated into the activated carbon adsorption device as desorption gas for desorption. The disadvantage of this method is that the system structure is relatively complicated, and the circulating gas may cause the concentration of organic waste gas inside the activated carbon adsorption device to be too high. If the temperature is too high, it will cause explosion, fire and other safety hazards.

Therefore, it is necessary to provide a safe and efficient exhaust gas treatment system that can save a lot of resources.

Contents of the invention

In view of the deficiencies in the prior art, the purpose of the present invention is to provide a preheating catalytic combustion system for purifying volatile organic waste gas, which can not only quickly and effectively remove VOCs waste gas in the waste gas, but also recover a large amount of VOCs Organic solvents, thus improving environmental protection and resource conservation have higher benefits.

In order to achieve the above object, the present invention provides the following technical solution: a preheating catalytic combustion system for purifying volatile organic waste gas, which is sequentially connected with a compression storage unit, an adsorption unit and a catalytic combustion unit, and the compression storage unit includes a container cavity 1. The blower that passes the VOCs exhaust gas into the container cavity and the regulating valve that communicates the container cavity with the adsorption unit, and there is a desiccant container between the container cavity and the blower; the adsorption unit includes sequentially connected condensers and activated carbon adsorption device, the activated carbon adsorption device is equipped with a heater, and the activated carbon adsorption device is respectively connected with the catalytic combustion unit and the blower; the catalytic combustion unit includes a catalytic bed and a burner, and the burner faces the catalytic bed, and the The catalytic bed is communicated with the chimney, and the chimney is provided with a heat exchanger, and the cold flow pipe of the heat exchanger is communicated with the adsorption unit and the burner.

By adopting the above technical solution, the blower blows the VOCs exhaust gas into the container cavity at a higher flow rate, and then operates the regulating valve to change the relationship between the intake velocity and the output velocity of the container cavity, so that the VOCs exhaust gas can flow in the container cavity Buffering in the middle avoids the excessive flow rate of VOCs exhaust gas in the system, which affects the efficiency of purification, thereby reducing the possibility of corrosion to the system.

Secondly, the condenser can condense the VOCs exhaust gas coming out of the container cavity, and the activated carbon adsorption device can absorb the remaining VOCs components in the exhaust gas, and then the remaining exhaust gas will enter the catalytic combustion unit. When the activated carbon adsorption device is saturated, at this time, close the entry of VOCs exhaust gas, and use the heater to heat the activated carbon in the activated carbon adsorption device, so that the adsorbed VOCs exhaust gas is desorbed and returned to the blower.

The VOCs exhaust gas entering the catalytic combustion unit will first be preheated by the heat exchanger, then it will flow to the burner to be ignited, and then the exhaust gas will flow to the catalytic bed, where the catalyst and residual temperature will be separated. Under the action, the remaining organic waste gas will be catalyzed and oxidized. After the above-mentioned treatment, the final exhaust gas will pass through the heat exchanger again, and the waste heat will be used to heat the VOCs exhaust gas entering the heat exchanger, which will help to increase the temperature of the VOCs exhaust gas, thereby not only improving the combustion efficiency of the final exhaust gas , but also reduce the waste of heat energy.

Preferably, several liquid attachment nets are arranged between the top and the bottom of the container cavity, and meanwhile, the bottom of the container cavity is equipped with a discharge valve.

By adopting the above technical scheme, the liquid attachment net is a net made of steel wire, which can provide attachment points for VOCs waste gas, so that on the one hand, it facilitates the liquefaction of VOCs waste gas on the liquid attachment net, thereby guiding the liquefied organic solvent. flow effect. On the other hand, the liquid attachment net can also filter VOCs exhaust gas, reducing excessive solid debris from entering the system and causing damage to the system. Furthermore, when there is too much organic solvent in the container cavity, the staff only needs to open the discharge valve, and the organic solvent can be transported to the designated place under the pressure in the container cavity, thereby improving the transport efficiency.

Preferably, cooling pipes for cooling exhaust gas inside the container cavity are distributed on the outer peripheral surface of the container cavity.

By adopting the above technical solution, the cooling pipeline can condense the VOCs exhaust gas in the container cavity from outside the container cavity. Since the environment in the container cavity is high pressure and low temperature, the VOCs exhaust gas is more likely to liquefy. Thereby, it is beneficial to improve the purification efficiency of VOCs exhaust gas.

Preferably, the number of the activated carbon adsorption devices is more than one, and they are arranged in parallel.

By adopting the above technical scheme, when one of the activated carbon adsorption devices is saturated, the staff only need to switch the VOCs exhaust gas to another activated carbon adsorption device, so that on the one hand, it can ensure the continuous treatment of VOCs exhaust gas, on the other hand It will not affect the desorption operation of the activated carbon adsorption device. This in turn increases the overall operating efficiency of the adsorption unit.

Preferably, the heater is a hot air pipe and a heating wire connected to the chimney, the hot air pipe faces the activated carbon of the activated carbon adsorption device, and the heating wire is located between the hot air pipe and the activated carbon.

By adopting the above technical solution, since the waste gas from the chimney is basically inorganic waste gas, but it also contains a large amount of waste heat, using it to desorb the activated carbon adsorption device can further improve the rational utilization of heat energy. At the same time, the heating wire can heat the hot air from the hot air pipe to ensure that it can reach the required temperature.

Preferably, there is a catalyst on the catalyst bed, the catalyst is in a honeycomb shape, and the pores of the catalyst face the burner.

By adopting the above technical solution, since the catalyst is in a honeycomb shape, it is beneficial to increase the contact area between the exhaust gas after combustion and the catalyst, thereby improving the catalytic oxidation efficiency of the exhaust gas.

Preferably, a flame arresting cover is provided before the catalytic bed and the burner, and the opening of the flame arresting cover faces to the side of the burner.

By adopting the above technical solution, the flame arresting cover is beneficial to block the flame to a certain extent, so as to avoid the damage of the catalyst caused by the flame directly burning to the catalytic bed. The flame arrester faces the burner, which can reverse the flame, thereby further reducing the possibility of the flame burning to the catalytic bed.

Preferably, the catalyst is composed of nickel-chromium alloy, clay and ceramic microbeads, and the mass ratio of the three is 10:7:3.

By adopting the above technical scheme, nickel-chromium alloy is a good catalyst for catalytic oxidation, and the addition of clay can not only improve the molding rate of the catalyst, but also help to improve the bonding strength inside the catalyst, thereby helping to prolong the service life of the catalyst . Moreover, since the surface of the ceramic microsphere has many pores, it is also beneficial to increase the contact area between the catalyst and the exhaust gas.

Preferably, a flame arresting cover is provided before the catalytic bed and the burner, and the opening of the flame arresting cover faces to the side of the burner.

By adopting the above technical solution, the flame arresting cover is beneficial to block the flame to a certain extent, so as to avoid the damage of the catalyst caused by the flame directly burning to the catalytic bed. The flame arrester faces the burner, which can reverse the flame, thereby further reducing the possibility of the flame burning to the catalytic bed.

Preferably, there is a spray tower between the chimney and the catalytic bed, and the spray liquid of the spray tower is a mixed liquid of hydrogen peroxide and saturated calcium hydroxide.

By adopting the above technical scheme, hydrogen peroxide is easy to decompose itself under acidic or neutral conditions to generate water and oxygen, while under alkaline conditions, it can be stored for a long time. Here, the hydrogen peroxide and saturated calcium hydroxide are mixed as the spray liquid, which is beneficial to prolong the activity time of the spray liquid.

In addition, after catalytic combustion, the main components of VOCs exhaust gas have become inorganic exhaust gases such as carbon dioxide, sulfur dioxide and water vapor, and a small amount of organic exhaust gases. The calcium hydroxide in the spray liquid can undergo metathesis reaction with the inorganic waste gas and generate calcium carbonate and calcium sulfate precipitates. At this time, the pH of the spray liquid tends to be neutral or weakly acidic, so that the hydrogen peroxide will decompose, and the oxygen produced can oxidize the remaining traces of organic waste gas, thereby further improving the treatment of VOCs waste gas ability.

Preferably, the spray tower is equipped with a waterproof ultraviolet lamp inside.

By adopting the above technical scheme, since the decomposition of hydrogen peroxide will produce a large amount of oxygen, and ultraviolet light can promote the reaction of oxygen to generate ozone, and the oxidation ability of ozone to organic waste gas is much greater than that of ordinary oxygen, thus further improving the treatment efficiency. Efficiency of VOCs exhaust gas.

In summary, the present invention has the following beneficial effects:

1. Preheat the VOCs exhaust gas entering the catalytic combustion unit by using the waste heat of the exhaust gas after combustion, which can not only improve the combustion efficiency, but also reduce the waste of waste heat;

2. By controlling the difference between the air inlet rate and the air outlet rate of the container cavity, the container cavity can buffer VOCs, which is conducive to improving the safety of the overall system;

3. The activated carbon adsorption device is heated by preheating the exhaust gas after combustion, which is beneficial to the desorption of VOCs exhaust gas, which not only improves the operating efficiency of the activated carbon adsorption device, but also further improves the utilization efficiency of waste heat.

Description of drawings

Fig. 1 is the schematic structural view of the preheating catalytic combustion system for purifying volatile organic waste gas in Embodiment 1;

Fig. 2 is the schematic diagram of the structure of the activated carbon adsorption device of embodiment one;

Fig. 3 is the structural representation of the catalytic combustion unit of embodiment one;

Fig. 4 is the structural representation of the container cavity of embodiment two;

5 is a schematic structural view of a preheating catalytic combustion system for purifying volatile organic waste gas in Embodiment 3;

Fig. 6 is the schematic diagram of the structure diagram of the activated carbon adsorption device of embodiment three;

Fig. 7 is the structural representation of the catalytic combustion unit of embodiment four;

Fig. 8 is a structural schematic diagram of a preheating catalytic combustion system for purifying volatile organic waste gas in Embodiment 5;

Fig. 9 is a schematic structural view of the spray tower of the fifth embodiment.

Reference signs: 1. Compression storage unit; 11. Blower; 12. Container cavity; 121. Unloading valve; 122. Cooling pipe; 123. Liquid attachment net; 13. Regulating valve; 14. Desiccant container; 2. Adsorption Unit; 21, condenser; 22, activated carbon adsorption device; 221, heater; 2211, hot air pipe; 2212, heating wire; 223, activated carbon block; 224, switching valve; 225, opening and closing valve; 3, catalytic combustion Unit; 31. Catalytic bed; 32. Burner; 33. Heat exchanger; 34. Fire hood; 4. Chimney; 5. Spray tower; 51. Waterproof ultraviolet lamp.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Embodiment one:

A preheating catalytic combustion system for purifying volatile organic waste gas, as shown in Figure 1, is sequentially connected to a compression storage unit 1, an adsorption unit 2 and a catalytic combustion unit 3. Among them, the compressed storage unit 1 is mainly composed of a blower 11 and a container cavity 12, wherein one end of the blower 11 is directly connected to the place where VOCs exhaust gas is generated, and the other end is connected to the container cavity 12, and the container cavity 12 is connected to the adsorption unit 2. At the same time, there is a regulating valve 13 between the container chamber 12 and the adsorption unit 2 , and the regulating valve 13 can regulate the air outlet rate of the container chamber 12 . Blower 11 can blow VOCs waste gas into container chamber 12 with higher flow rate like this, then operates regulating valve 13, to regulate the relation of the intake velocity of container chamber 12 and the gas outlet velocity, container chamber 12 can play a role to VOCs waste gas like this The buffering effect ensures the stability of VOCs exhaust gas flowing in the system.

As shown in accompanying drawings 1 and 2, the adsorption unit 2 is mainly composed of a condenser 21 and an activated carbon adsorption device 22, wherein one end of the condenser 21 communicates with the regulating valve 13, and the other end communicates with the bottom of the activated carbon adsorption device 22 . The number of activated carbon adsorption devices 22 can be determined according to actual needs, here the number of activated carbon adsorption devices 22 is two, and the two activated carbon adsorption devices 22 are arranged in parallel. In addition, the activated carbon adsorption device 22 has an activated carbon block 223 arranged in parallel, and the activated carbon adsorption device has a heater 221 under the activated carbon block. The tops of the two activated carbon adsorption devices 22 are respectively connected with the blower 11 and the catalytic combustion unit 3 , and the top and bottom of each activated carbon adsorption device 22 are provided with switching valves 224 and opening and closing valves 225 respectively. In this way, when one of the activated carbon adsorption devices 22 is saturated with adsorption, the opening and closing valve 225 can close the activated carbon adsorption device 22 so that exhaust gas cannot enter the activated carbon adsorption device 22 . at the same time. The on-off valve 225 on another activated carbon adsorption device 22 will be opened. In this process, the heater 221 in the activated carbon adsorption device 22 closed by the opening and closing valve 225 will heat the activated carbon block, so that the VOCs waste gas will be desorbed, and at this time, the switching valve 224 will make the activated carbon adsorption device 22 and the blower 11 It is connected and disconnected from the catalytic combustion unit 3, so that the desorbed VOCs exhaust gas will flow back and continue to be processed. And another activated carbon adsorption device 22 is disconnected from the air blower 11 under the operation of the switching valve 224, and communicates with the catalytic combustion unit 3. Therefore, the continuous production of the adsorption unit 2 is ensured, and the efficiency of the overall exhaust gas purification system is greatly improved.

In addition, as shown in FIG. 1 and FIG. 3 , the catalytic combustion unit 3 mainly includes a catalytic bed 31 and a burner 32 , wherein the burner 32 communicates with the catalytic bed 31 and the burner 32 faces the catalytic bed 31 . The catalytic bed 31 is also in communication with a chimney 4 . Simultaneously, there is a heat exchanger 33 between the chimney 4 and the catalytic bed 31, the heat flow pipe in the heat exchanger 33 communicates with the catalytic bed 31 and the chimney 4, and the cold flow pipe communicates with the adsorption unit 2 and the burner 32 . In this way, the exhaust gas after adsorption can be heated by the exhaust gas after catalytic combustion, and such circulation is conducive to improving the utilization rate of waste heat by organic waste gas. In addition, when the burned VOCs exhaust gas cannot be burned due to its low concentration, fuel can be added to the burner to burn the VOCs exhaust gas.

Embodiment two:

A preheating catalytic combustion system for purifying volatile organic waste gas, as shown in Figure 4, on the basis of Embodiment 1, the outer peripheral surface of the container cavity 12 is also provided with a cooling pipe 122, and cooling pipes 122 flow therein. liquid. The cooling liquid can cool the VOCs exhaust gas in the container chamber 12, and contribute to the liquefaction efficiency of the VOCs exhaust gas. At the same time, a number of liquid attachment nets 123 are connected between the top and bottom of the container chamber 12, and the number of liquid attachment nets 123 can be determined according to actual conditions. The liquid attachment network 123 can provide attachment points for the VOCs waste gas, which on the one hand helps to improve the liquefaction efficiency of the VOCs waste gas, and on the other hand can also improve the diversion of the liquefied organic solvent so that it can flow to the container as soon as possible Cavity 12 bottom. Moreover, the bottom of the container chamber 12 here also has a discharge valve 121, so that when the organic solvent in the container chamber 12 is too much, the staff only needs to open the discharge valve 121, and the organic solvent can be discharged in the container chamber 12. Under the action of internal pressure, it is transported to the designated place, thus improving the transport efficiency.

Embodiment three:

A preheating catalytic combustion system for purifying volatile organic waste gas, shown in conjunction with accompanying drawings 5 and 6, based on the second embodiment, where the heater 221 is a hot air pipe 2211 communicating with the chimney 4 and The heating wire 2212 and the hot air pipe 2211 are facing the activated carbon of the activated carbon adsorption device 22, and the heating wire 2212 is located between the hot air pipe 2211 and the activated carbon. In this way, on the one hand, the residual heat of the exhaust gas after combustion can be efficiently utilized, and on the other hand, the exhaust gas from the chimney 4 can be heated through the heating wire 2212 to reach the required temperature, which facilitates the desorption of the activated carbon.

Embodiment four:

A preheating catalytic combustion system for purifying volatile organic waste gas, as shown in FIG. 7 , based on the third embodiment, the catalyst on the catalytic bed 31 is honeycomb-shaped, and its holes face the burner 32 . Meanwhile, the catalyst 311 is composed of nickel-chromium alloy, clay and ceramic microbeads, and the mass ratio of the three is 10:7:3. In this way, on the one hand, the catalytic oxidation efficiency of exhaust gas can be improved under the action of nickel-chromium alloy, on the other hand, clay is beneficial to improve the structural strength of the catalyst, and the pores of the ceramic microspheres and the catalyst itself increase the contact area between the catalyst and the exhaust gas. , which is conducive to improving the efficiency of catalytic oxidation of exhaust gas. In addition, there is a flame arresting cover 34 between the catalytic bed 31 and the burner 32 with the cover opening facing the burner 32, which can reduce the probability of direct combustion of the flame to the catalyst, thereby helping to prolong the service life of the catalyst.

Embodiment five:

A preheating catalytic combustion system for purifying volatile organic waste gas, as shown in Figure 8 and Figure 9, based on Embodiment 4, there is a spray tower 5 between the chimney 4 and the catalytic bed 31, specifically The location is between the heat exchanger 33 and the chimney 4 . In addition, the spray liquid in the spray tower 5 is a mixture of hydrogen peroxide and saturated calcium hydroxide, and the volume ratio is 2;1. Because the main components of VOCs exhaust gas after catalytic combustion have become inorganic exhaust gases such as carbon dioxide, sulfur dioxide and water vapor, and a small amount of organic exhaust gases. The calcium hydroxide in the spray liquid can undergo metathesis reaction with the inorganic waste gas and generate calcium carbonate and calcium sulfate precipitates. At this time, the pH of the spray liquid tends to be neutral or weakly acidic, so that the hydrogen peroxide will decompose, and the oxygen produced can oxidize the remaining traces of organic waste gas, thereby further improving the treatment of VOCs waste gas ability.

In addition, there is a waterproof ultraviolet lamp 51 inside the spray tower 5. The ultraviolet rays generated by the waterproof ultraviolet lamp 51 can promote the reaction of oxygen generated by the decomposition of hydrogen peroxide to generate ozone, and the oxidation ability of ozone for organic waste gas is much greater than that of ordinary oxygen. , thus further improving the efficiency of treating VOCs exhaust gas.

Furthermore, a desiccant container 14 is also communicated between the air blower 11 and the container chamber 12, and the selection of the desiccant in the desiccant container 14 can be selected according to the actual situation. Here, desiccants such as aluminum oxide and alum are used, so that It can pre-dehydrate VOCs waste gas, which is beneficial to improve the purity of the liquefied organic solvent. And here the number of desiccant containers 14 is two, and they are arranged in parallel. Simultaneously, the chimney is also connected with the two desiccant containers 14 respectively, so that when the desiccant in one desiccant container 14 absorbs moisture and is saturated, the VOCs waste gas can be switched to another desiccant container 14, and then in the chimney 4 The hot air after combustion can dry the saturated desiccant, thus realizing the recycling of the desiccant.

This specific embodiment is only an explanation of the present invention, and it is not a limitation of the present invention. Those skilled in the art can make modifications to this embodiment without creative contribution as required after reading this specification, but as long as they are within the rights of the present invention All claims are protected by patent law.

Claims (10)

1. A preheating catalytic combustion system for purifying volatile organic waste gas, which is sequentially connected with a compression storage unit (1), an adsorption unit (2) and a catalytic combustion unit (3), characterized in that: the compression storage unit ( 1) including a container chamber (12), a blower (11) for passing VOCs waste gas into the container chamber (12), and a regulating valve (13) communicating with the container chamber (12) and the adsorption unit (2), and the container chamber ( 12) There is a desiccant container (14) between the blower (11); the adsorption unit (2) includes a condenser (21) and an activated carbon adsorption device connected in sequence, and the activated carbon adsorption device (22) has a Heater (221) is arranged, and activated carbon adsorption device (22) is connected with catalytic combustion unit (3) and blower (11) respectively; Described catalytic combustion unit (3) comprises catalytic bed (31) and burner (32) , the burner (32) faces the catalytic bed (31), the catalytic bed (31) communicates with the chimney (4), and there is a heat exchanger (33) in the chimney (4), the The cold flow pipe of the heat exchanger (33) communicates with the adsorption unit (2) and the burner (32). 2. A preheating catalytic combustion system for purifying volatile organic waste gas according to claim 1, characterized in that: several steel wires (123) are arranged between the top and the bottom of the container cavity (12), Meanwhile, the bottom of the container chamber (12) is provided with a discharge valve (121). 3. A preheating catalytic combustion system for purifying volatile organic waste gas according to claim 2, characterized in that: the outer peripheral surface of the container cavity (12) is distributed for cooling the exhaust gas inside the container cavity (12) The cooling pipe (122) road. 4. A preheating catalytic combustion system for purifying volatile organic waste gas according to claim 1, characterized in that: the number of activated carbon adsorption devices (22) is more than one, and they are arranged in series. 5. A preheating catalytic combustion system for purifying volatile organic waste gas according to claim 4, characterized in that: the heater (221) is a hot air pipe (2211) connected to the chimney (4) and a heating wire (2212), the hot air pipe (2211) faces the activated carbon of the activated carbon adsorption device (22), and the heating wire (2212) is located between the hot air pipe (2211) and the activated carbon. 6. A preheating catalytic combustion system for purifying volatile organic waste gas according to claim 1, characterized in that: the catalyst bed (31) is provided with a catalyst (311), and the catalyst (311) is formed into Honeycomb shape, and the pores of the catalyst (311) face the burner (32). 7. A preheating catalytic combustion system for purifying volatile organic waste gas according to claim 6, characterized in that: the catalyst (311) is composed of nickel-chromium alloy, clay and ceramic microspheres, and the three The mass ratio is 10:7:3. 8. A preheating catalytic combustion system for purifying volatile organic waste gas according to claim 6, characterized in that: a fire arresting cover (34) is provided before the catalytic bed (31) and the burner (32) , the mouth of the flame arresting cover (34) faces the burner (32) side. 9. A preheating catalytic combustion system for purifying volatile organic waste gas according to claim 1, characterized in that: there is a spray tower (5) between the chimney (4) and the catalytic bed (31) , the spray liquid of described spray tower (5) is the mixed liquid of hydrogen peroxide and saturated calcium hydroxide. 10. A preheating catalytic combustion system for purifying volatile organic waste gas according to claim 9, characterized in that: the spray tower (5) is equipped with a waterproof ultraviolet lamp (51) inside.