Method and system for treating VOCs (Volatile Organic Compounds) waste gas

Abstract

The invention relates to a VOCs waste gas treatment method and system, and belongs to the technical field of waste gas treatment. Comprising the following steps: pre-treating the VOCs waste gas to enable the oxygen content in the VOCs waste gas to reach a preset amount so as to obtain to-be-treated waste gas; carrying out thermal combustion treatment on the waste gas to be treated by utilizing a disc type photo-thermal reactor to obtain treated gas; the disc type photo-thermal reactor comprises a high-temperature reactor for accommodating waste gas to be treated and a disc type photo-thermal device for heating the high-temperature reactor by utilizing photo-thermal; solar energy of renewable energy is adopted as an energy supply source to replace auxiliary fuel, a high-temperature environment generated by a disc type photo-thermal device is utilized to heat a thermodynamic reactor, the thermodynamic reactor treats VOCs waste gas through a thermal combustion method, the requirement for creating a temperature environment through the auxiliary fuel is lowered, and the problem that at present, thermal combustion needs the auxiliary fuel is solved. Meanwhile, the mass concentration of non-methane hydrocarbon in the treated gas is not higher than 20 mg / m < 3 >, and the removal efficiency is not lower than 97%.

Description

Technical Field

[0001] The present application relates to the technical field of waste gas treatment, and in particular to a method and system for treating VOCs waste gas. Background Art

[0002] Most VOCs have the common characteristics of low boiling point, high vapor pressure and strong photochemical reactivity. They are volatile at room temperature, have pungent odor and are toxic, and are flammable and explosive. Under ultraviolet light, the hydrocarbons contained in VOCs react with NO x 、SO 2 A photochemical chain reaction occurs, generating secondary pollutants such as O3, peroxyacetyl nitrate (PAN), aldehydes, and organic acids, which are released into the air along with odor and foul smell. O3 further oxidizes SO in the atmosphere. 2 、NO x and VOCs, generating SO 2- 、NO - These anions react with NH + , Ca 2+ Mg 2+ The combination of cations and other substances forms inorganic PM2.5. The primary pollutants formed by direct emission of VOCs and the secondary pollutants formed by a series of reactions of VOCs can constitute photochemical smog in the air; in addition, VOCs will form highly active free radicals under light, and the highly active free radicals and other intermediates will further react with toluene, xylene, etc. to produce semi-volatile products, which will then be distributed between the gas phase and the particle phase. Under suitable environmental conditions, semi-volatile organic matter will enter the particle phase, increasing the number of particles. These generated particles are secondary organic aerosols. Therefore, VOCs need to be controlled.

[0003] VOCs treatment technologies can be divided into two categories: recovery and removal. Recovery technology mainly uses physical methods to pass VOCs-containing waste gas through proprietary devices to separate its components and then purify it; removal technology uses chemical methods to degrade VOCs into non-toxic and odorless gases, which is a destructive method.

[0004] In most cases of treating organic waste gas, the concentration of VOCs in the waste gas is generally very low, and the air volume is quite large. Therefore, the combustion method is often used to purify organic waste gas because it is not economically viable to recover the organic solvents in the waste gas, or it is difficult to reuse the recovered solvents, and secondary pollution may occur during the recovery process. The combustion method is based on the characteristics that organic compounds in the waste gas can be burned and oxidized. Its purpose is to convert the oxidizable components in the waste gas into harmless substances through combustion. In the case of pure hydrocarbons in the waste gas, it is converted into CO2 and H2O.

[0005] There are three main types of combustion methods for organic waste gas purification, namely direct combustion, thermal combustion and catalytic combustion. When the VOC concentration in the waste gas is very high, the waste gas can be used as fuel to burn, so it is called direct combustion; in the case of thermal combustion and catalytic combustion, the concentration of combustibles in the treated waste gas is too low. Auxiliary fuel must be used to achieve combustion, so it is called thermal combustion, also known as post-combustion, smokeless combustion; catalytic combustion also belongs to thermal combustion, but it is separated separately because of its catalytic reaction characteristics. The purpose of catalytic combustion is to use the catalytic action of the catalyst to reduce the oxidation reaction temperature and increase the reaction rate.

[0006] Direct combustion is to use organic waste gas as fuel for combustion. It is usually suitable for the concentration of combustibles contained in the waste gas to be very high, and its concentration is generally higher than the upper limit of the explosion concentration, with a correspondingly high combustion calorific value. It can maintain the temperature required for combustion without adding auxiliary fuel. The fire and smoke combustion temperature of the direct combustion method is generally about 1100℃. Bright flames are produced during direct combustion, so it is also called fire and smoke combustion. In the case of organic waste gas containing hydrocarbons, the products after direct combustion are mainly CO2 and H2O. In another case, although the concentration of combustibles in the waste gas is very low, it can sometimes be selected to be directly burned in the existing combustion chamber in production. For example, the organic waste gas replaces the air required by the boiler combustion chamber; otherwise, thermal combustion can only be used, that is, adding auxiliary fuel for combustion. The direct combustion method is not suitable for the purification of large air volume and low concentration of organic waste gas. The direct combustion method is simple in design and mature in technology, but it has the disadvantage that the combustion heat cannot be effectively utilized. If it is not handled properly, a large amount of harmful gases and smoke, as well as heat radiation, will also be generated.

[0007] Thermal combustion method Because the concentration of combustibles contained in organic waste gas is extremely low, it cannot ignite and rely on itself to maintain combustion, so the heat generated by the combustion of auxiliary fuel must be used to increase the temperature of the waste gas to oxidize the VOC in the waste gas and convert it into harmless substances. Thermal combustion equipment is mainly composed of an auxiliary burner and a combustion chamber. When the temperature of the combustion chamber reaches the temperature that can ignite the organic waste gas, the waste gas is introduced into the combustion chamber for oxidation combustion, and then the purified gas is discharged into the atmosphere through the chimney. According to the amount of air in the waste gas, different burners are used, and the disadvantage is whether to supplement the combustion air. In order to ensure that VOC can be completely oxidized, the waste gas must have enough residence time in the combustion chamber. Thermal combustion has a simple structure, low investment cost, and convenient operation. It can treat almost all organic waste gases and meet the emission requirements of regulations, but it requires auxiliary fuel, so the operating cost is very high.

[0008] The catalytic combustion method uses catalysts to reduce the activation energy required for the oxidation of organic matter and increase the reaction rate, so that oxidation combustion can be carried out at a lower temperature. Organic matter is converted into harmless substances. The temperature should generally be controlled at 300-350 ° C. In catalytic combustion, solid catalysts are generally used, so heterogeneous catalytic reactions are involved. Commonly used catalysts are mainly carrier catalysts, that is, the active components of the catalyst are deposited on ceramic or metal carriers. Most of the catalysts used in the catalytic combustion of organic waste gas use ceramic materials as carriers and are made into shapes such as particles, cylinders or hollow cylinders and honeycombs. Although the oxidation temperature of catalytic combustion is significantly lower than that of non-catalytic thermal combustion, the conversion operation of harmful substances is more economical. However, its disadvantages are: there are certain requirements for the organic waste gas to be treated, that is, it cannot contain substances that poison the catalyst, inhibit the reaction, block or cover the active center of the catalyst; in addition, the cost of the catalyst and the frequent need to replace it also restrict its application. The catalyst is prone to blockage, sintering, poisoning, damage and activity decay; there are restrictions on the composition and concentration of certain pollutants.

[0009] Among the many VOCs treatment technologies, thermal combustion equipment is widely used due to its advantages such as simplicity, low investment cost, easy operation, wide range of waste gas treatment and low emission temperature. However, the problem of high operating costs due to the need for auxiliary fuel still needs to be solved. Summary of the invention

[0010] The present application provides a method and system for treating VOCs waste gas to improve the current problem of thermal combustion requiring auxiliary fuel.

[0011] In a first aspect, the present application provides a method for treating VOCs waste gas, the method comprising:

[0012] Pre-treating the VOCs waste gas so that the oxygen content in the VOCs waste gas reaches a preset amount to obtain waste gas to be treated;

[0013] The waste gas to be treated is subjected to thermal combustion treatment by using a dish-type photothermal reactor to obtain treated gas and complete the treatment; the dish-type photothermal reactor comprises a high-temperature reactor for accommodating the waste gas to be treated and a dish-type photothermal device for heating the high-temperature reactor by using photothermal energy.

[0014] As an optional implementation, the temperature of the thermal combustion treatment is 700-800°C.

[0015] As an optional implementation manner, the residence time of the waste gas to be treated in the dish-type photothermal reactor is greater than 2s.

[0016] As an optional implementation manner, the volume content of oxygen in the waste gas to be treated is at least 10%.

[0017] As an optional implementation, the concentration of the controlled component in the VOCs waste gas is lower than 25% of the lower explosion limit of its most explosive component or the lower explosion limit of the mixed gas.

[0018] As an optional embodiment, the concentration of VOCs gas in the VOCs waste gas is 500-50000 mg / m 3 .

[0019] As an optional implementation, the pre-treatment of the VOCs waste gas to make the oxygen content in the VOCs waste gas reach a preset amount to obtain the waste gas to be treated includes:

[0020] The VOCs waste gas and the oxygen-containing gas are mixed so that the oxygen content in the VOCs waste gas reaches a preset amount to obtain the waste gas to be treated.

[0021] As an optional embodiment, the method further includes utilizing waste heat from the treated gas, wherein the waste heat utilization includes using the waste heat for a Stirling generator and heating VOCs waste gas.

[0022] In a second aspect, the present application provides a VOCs waste gas treatment system, the system comprising:

[0023] Exhaust gas pipeline, used to transport VOCs exhaust gas;

[0024] An oxygen-containing gas pipeline is used to transport the oxygen-containing gas, and the oxygen-containing gas pipeline is connected to the waste gas pipeline to pre-treat the VOCs waste gas so that the oxygen content in the VOCs waste gas reaches a preset amount to obtain the waste gas to be treated;

[0025] The disc-type photothermal reactor is used to perform thermal combustion treatment on the waste gas to be treated to obtain treated gas; the disc-type photothermal reactor includes a high-temperature reactor for accommodating the waste gas to be treated and a disc-type photothermal device for heating the high-temperature reactor by photothermal means; the high-temperature reactor is connected to the waste gas pipeline to receive the waste gas to be treated.

[0026] As an optional embodiment, the system also includes: a waste heat utilization component, which includes a Stirling generator and a heat exchanger, wherein the Stirling generator is connected to the high-temperature reactor to receive the treated gas for primary waste heat utilization; the hot side of the heat exchanger is connected to the Stirling generator to receive the treated gas after primary waste heat utilization, and the cold side of the heat exchanger is connected to the exhaust gas pipeline to perform secondary waste heat utilization on the treated gas to heat the VOCs exhaust gas.

[0027] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0028] The method provided in the embodiment of the present application uses renewable energy solar energy as an energy source to replace auxiliary fuel, and uses the high temperature environment generated by the dish-type photothermal device to heat the thermal reactor. The thermal reactor uses a thermal combustion method to treat VOCs waste gas, which reduces the need for auxiliary fuel to create a temperature environment and improves the current problem of thermal combustion requiring auxiliary fuel. At the same time, the mass concentration of non-methane total hydrocarbons in the treated gas is not higher than 20mg / m 3 , the removal efficiency is not less than 97%. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0031] Figure 1 A schematic diagram of a process for a method provided in an embodiment of the present application;

[0032] Figure 2 A schematic diagram of the structure of the system provided in the embodiment of the present application;

[0033] Figure 3 This is the cycle flow and TS diagram of the Stirling generator. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0035] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0036] Figure 1 A flow chart of the method provided in the embodiment of the present application is as follows: Figure 1 As shown, the embodiment of the present application provides a method for treating VOCs waste gas, the method comprising:

[0037] S1. Pre-treating the VOCs waste gas so that the oxygen content in the VOCs waste gas reaches a preset amount to obtain the waste gas to be treated;

[0038] In some embodiments, the pre-treatment of the VOCs waste gas to make the oxygen content in the VOCs waste gas reach a preset amount to obtain the waste gas to be treated includes: mixing the VOCs waste gas and an oxygen-containing gas to make the oxygen content in the VOCs waste gas reach a preset amount to obtain the waste gas to be treated. Specifically, the oxygen-containing gas can be selected from air.

[0039] In some embodiments, the concentration of the controlled component in the VOCs gas should be less than 25% of the lower explosion limit of the most explosive component or mixed gas. The VOCs gas concentration of the VOCs waste gas is 500-50000 mg / m 3 between.

[0040] S2. Use a dish-type photothermal reactor to perform thermal combustion treatment on the waste gas to be treated to obtain treated gas and complete the treatment; the dish-type photothermal reactor includes a high-temperature reactor for accommodating the waste gas to be treated and a dish-type photothermal device for heating the high-temperature reactor using photothermal heat.

[0041] In some embodiments, the high temperature environment of 700-800°C generated by the dish-type photothermal focus is used to provide reaction heat for waste gas treatment, creating thermal conditions for the decomposition of VOCs gas, replacing the current thermal combustion technology to provide heat with auxiliary fuel, saving fuel.

[0042] In some embodiments, the residence time of the VOCs gas in the thermal reactor is greater than 2 seconds to provide sufficient reaction time.

[0043] In some embodiments, when the reactor temperature is between 700° C. and 800° C., the oxygen content in the flue gas is 10% to meet the processing requirements, thereby reducing the injection of air volume and the size of the fan equipment.

[0044] S3. The method also includes utilizing waste heat from the treated gas, wherein the waste heat utilization includes being used for a Stirling generator and heating VOCs exhaust gas.

[0045] The high-temperature solar thermal energy absorbed by the system and the heat energy generated by exhaust gas combustion are recovered in a combined manner. First, a Stirling generator is used to generate electricity with a voltage of 380V or 690V AC. It can be directly connected to the grid to convert the heat energy absorbed by the system into electrical energy. Secondly, low-grade heat energy is exchanged with low-temperature VOCs gas to recover energy, thereby maximizing energy utilization.

[0046] This method uses solar energy, a renewable energy source, as an energy source to replace auxiliary fuels, and uses the high temperature environment generated by the dish-type photothermal device to heat the thermal reactor. The thermal reactor uses thermal combustion to treat VOCs waste gas, reducing the need for auxiliary fuels to create a temperature environment and improving the current problem of thermal combustion requiring auxiliary fuels. At the same time, the mass concentration of non-methane total hydrocarbons in the treated gas is no more than 20mg / m 3 , the removal efficiency is not less than 97%.

[0047] Figure 2 A schematic diagram of the structure of the system provided in the embodiment of the present application, such as Figure 2 As shown, based on a general inventive concept, the embodiment of the present application also provides a VOCs waste gas treatment system, the system comprising:

[0048] Exhaust gas pipeline, used to transport VOCs exhaust gas;

[0049] An oxygen-containing gas pipeline is used to transport the oxygen-containing gas, and the oxygen-containing gas pipeline is connected to the waste gas pipeline to pre-treat the VOCs waste gas so that the oxygen content in the VOCs waste gas reaches a preset amount to obtain the waste gas to be treated;

[0050] The disc-type photothermal reactor is used to perform thermal combustion treatment on the waste gas to be treated to obtain treated gas; the disc-type photothermal reactor includes a high-temperature reactor for accommodating the waste gas to be treated and a disc-type photothermal device for heating the high-temperature reactor by photothermal means; the high-temperature reactor is connected to the waste gas pipeline to receive the waste gas to be treated.

[0051] The system is implemented based on the above method. The specific steps of the method can refer to the above embodiment. Since the system adopts part or all of the technical solutions of the above embodiment, it has at least all the beneficial effects brought by the technical solutions of the above embodiment, which will not be repeated here.

[0052] In some embodiments, the system also includes: a waste heat utilization component, which includes a Stirling generator and a heat exchanger, wherein the Stirling generator is connected to the high-temperature reactor to receive the treated gas for primary waste heat utilization; the hot side of the heat exchanger is connected to the Stirling generator to receive the treated gas after primary waste heat utilization, and the cold side of the heat exchanger is connected to the exhaust gas pipeline to perform secondary waste heat utilization on the treated gas to heat the VOCs waste gas.

[0053] The Stirling engine is an external combustion closed cycle engine, mainly composed of an external heating system, a closed cycle system (including a regenerator, an expansion chamber, a compression chamber, a heater and a cooler), a transmission system (including a piston rod, a diamond mechanism and a crankshaft, etc.) and a control system. Compared with common heat engines such as internal combustion engines, gas turbines, and steam engines, the Stirling engine has many advantages.

[0054] First of all, the Stirling engine has a wide range of heat source applicability, and can use a variety of heat sources including coal, straw, natural gas, biogas, solar energy, alcohol, industrial waste heat, etc. to provide driving force for it. Secondly, the Stirling engine has a high efficiency of energy utilization, and its ideal cycle - the Stirling cycle has the same heat-to-work conversion efficiency as the Carnot cycle. Moreover, the Stirling engine emits very little pollution. It has a continuous combustion process and can operate under sufficient excess air, so the harmful gases emitted during operation are relatively small. And because the Stirling engine does not have deflagration and knock during operation, it runs relatively quietly and produces very little noise, and is known as a silent engine. In addition, the working fluid pressure changes relatively smoothly during the operation of the equipment; when the bearing load allows, the torque is relatively uniform within the entire speed range; the overload working capacity is relatively excellent; there are no valves, high-pressure injection systems, piston rings and other parts that are prone to failure, so the work is relatively reliable and the maintenance cost is low. Generally speaking, increasing the temperature of the high-temperature heat source and reducing the temperature of the low-temperature cold source are common means to improve the efficiency of the Stirling engine, and the engine efficiency can reach 30-40%.

[0055] Figure 3 The cycle flow and TS diagram of the Stirling generator are as follows: Figure 3 As shown, in the process 1-2, the working fluid contacts the low-temperature heat source, releases heat to the low-temperature heat source and compresses it; in the process 2-3, the working fluid enters the regenerator and contacts it, absorbs the heat of the regenerator and heats up at an isochoric rate; in the process 3-4, the working fluid contacts the high-temperature heat source, absorbs the heat of the high-temperature heat source, expands at an isothermal rate and performs work externally; in the process 4-1, the working fluid enters the regenerator and contacts it, releases heat to the regenerator and performs isochoric cooling. The working fluid of the Stirling engine continuously performs these four processes to complete the cycle and perform work externally.

[0056] The whole process of VOCs waste gas in the system is as follows: the VOCs waste gas sent from each collection point enters the gas buffer tank and stabilizes before entering the heat exchanger to recover the heat of the treated gas for heating the external VOCs waste gas, and then determines whether to add oxygen-containing gas before entering the disc-type photothermal reactor according to the oxygen content in the VOCs waste gas to provide sufficient oxygen for thermal combustion treatment. If oxygen-containing gas is required, air is generally mixed into the waste gas pipeline in front of the disc-type photothermal reactor. The waste gas to be treated with mixed and adjusted oxygen content enters the coil of the high-temperature reactor at the focus of the disc-type photothermal device. The temperature in the coil is controlled at 700-800℃, and the heat is provided by the disc-type photothermal device using solar energy. The residence time of the waste gas to be treated in the high-temperature reactor is about 2s, which ensures that the reactants can react completely and the waste gas in the VOCs gas is fully decomposed; the temperature of the treated gas after the reaction will increase due to the dual effects of the disc concentrated heating and the heat generated by the VOCs gas reaction, and enter the subsequent heat recovery process. The VOCs gas reaction process ends and the gas meets the emission indicators required by the specification. The treated gas at about 900℃ exchanges heat with the circulating medium at the hot end of the Stirling generator, transferring heat to the hydrogen in the heat pipe of the Stirling engine. The high-temperature and high-pressure hydrogen drives the Stirling engine to do work. The flue gas after heat exchange with the hot head of the Stirling generator further exchanges heat with the VOCs waste gas to be treated, raising its temperature and reducing the heat heated by the disc-type photothermal device. The treated gas temperature after heat exchange is about 120℃ and enters the exhaust pipe for discharge.

[0057] The system has the advantages of simple equipment, low investment cost, easy operation, wide range of waste gas treatment, and low emission temperature. It uses renewable energy solar energy as an alternative energy source, and uses the focusing effect of the dish lens system to generate high temperature to achieve the effect of the combustion chamber, providing new ideas for thermal combustion treatment of VOCs technology.

[0058] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0059] In this application, unless otherwise specified, directional words such as "upper" and "lower" used refer specifically to the directions of the drawings in the accompanying drawings. In addition, in the description of the specification of this application, the terms "include", "comprise", etc. mean "including but not limited to".

[0060] In this article, 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 that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A, B can be singular or plural. In this article, "at least one" refers to one or more, and "multiple" refers to two or more. "At least one", "the following at least one (individual)" or similar expressions refer to any combination of these items, including any combination of single (individual) or plural (individual). For example, "at least one (individual) of a, b, or c", or "at least one (individual) of a, b, and c", can all represent: a, b, c, ab (i.e. a and b), ac, bc, or abc, wherein a, b, c can be single or multiple respectively.

[0061] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for treating VOCs waste gas, characterized in that: The method comprises: Pre-treating the VOCs waste gas so that the oxygen content in the VOCs waste gas reaches a preset amount to obtain waste gas to be treated; The waste gas to be treated is subjected to thermal combustion treatment by using a dish-type photothermal reactor to obtain treated gas and complete the treatment; the dish-type photothermal reactor comprises a high-temperature reactor for accommodating the waste gas to be treated and a dish-type photothermal device for heating the high-temperature reactor by using photothermal energy.

2. The method for treating VOCs waste gas according to claim 1, characterized in that: The temperature of the thermal combustion treatment is 700-800°C.

3. The method for treating VOCs waste gas according to claim 1, characterized in that: The residence time of the waste gas to be treated in the dish-type photothermal reactor is greater than 2s.

4. The method for treating VOCs waste gas according to claim 1, characterized in that: The volume content of oxygen in the waste gas to be treated is at least 10%.

5. The method for treating VOCs waste gas according to claim 1, characterized in that: The concentration of the controlled component in the VOCs waste gas is lower than 25% of the lower explosion limit of its most explosive component or the lower explosion limit of the mixed gas.

6. The method for treating VOCs waste gas according to claim 1, characterized in that: The concentration of VOCs gas in the VOCs waste gas is 500-50000 mg / m 3 .

7. The method for treating VOCs waste gas according to claim 1, characterized in that: The pre-treatment of the VOCs waste gas to make the oxygen content in the VOCs waste gas reach a preset amount to obtain the waste gas to be treated includes: The VOCs waste gas and the oxygen-containing gas are mixed so that the oxygen content in the VOCs waste gas reaches a preset amount to obtain the waste gas to be treated.

8. The method for treating VOCs waste gas according to claim 6, characterized in that: The method further includes utilizing waste heat from the treated gas, wherein the waste heat utilization includes using the waste heat for a Stirling generator and heating VOCs exhaust gas.

9. A VOCs waste gas treatment system, characterized in that: The system comprises: Exhaust gas pipeline, used to transport VOCs exhaust gas; An oxygen-containing gas pipeline is used to transport the oxygen-containing gas, and the oxygen-containing gas pipeline is connected to the waste gas pipeline to pre-treat the VOCs waste gas so that the oxygen content in the VOCs waste gas reaches a preset amount to obtain the waste gas to be treated; The disc-type photothermal reactor is used to perform thermal combustion treatment on the waste gas to be treated to obtain treated gas; the disc-type photothermal reactor includes a high-temperature reactor for accommodating the waste gas to be treated and a disc-type photothermal device for heating the high-temperature reactor by photothermal means; the high-temperature reactor is connected to the waste gas pipeline to receive the waste gas to be treated.

10. The VOCs waste gas treatment system according to claim 9, characterized in that: The system also includes: a waste heat utilization component, which includes a Stirling generator and a heat exchanger. The Stirling generator is connected to the high-temperature reactor to receive the treated gas for primary waste heat utilization; the hot side of the heat exchanger is connected to the Stirling generator to receive the treated gas after primary waste heat utilization, and the cold side of the heat exchanger is connected to the exhaust gas pipeline to perform secondary waste heat utilization on the treated gas to heat the VOCs exhaust gas.

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