Petrochemical VOCs waste gas treatment device and method

Abstract

The invention relates to a petrochemical industry VOCs waste gas treatment device, the petrochemical industry VOCs waste gas treatment device comprises: a pretreatment system, the pretreatment system comprises a zeolite rotating wheel and a heating unit, the zeolite rotating wheel comprises an adsorption zone, a desorption zone and a cooling zone, the desorption zone and the cooling zone are both communicated with the heating unit; and the acting system comprises a Stirling engine, and the desorption area is communicated with the Stirling engine. Petrochemical VOCs waste gas is firstly purified and concentrated through the zeolite rotating wheel, then concentrated gas obtained through concentration serves as fuel of the Stirling engine, heat energy of the fuel is converted into mechanical energy, and combustion waste heat of the petrochemical VOCs waste gas can be fully utilized.

Description

Technical Field

[0001] The present application relates to the field of waste gas treatment, and in particular to petrochemical waste gas. Background Art

[0002] The petrochemical industry produces a large amount of volatile organic compounds (VOCs) waste gas. 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 toxicity, 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.

[0003] VOCs treatment technologies are diverse, waste gas components are complex and their applicability varies greatly. According to the "Comprehensive Control Plan for Volatile Organic Compounds in Key Industries" issued by the Ministry of Environment and Ecology, for VOCs under different conditions, solvent recovery is preferred for high-concentration waste gas, such as absorption technology, condensation technology and membrane separation technology. Although the operating cost is relatively high, it can generate certain economic benefits by recovering organic matter; adsorption technology is suitable for waste gas with large air volume and high concentration. Its investment cost is slightly higher than membrane separation technology, and its operating cost is lower. It first increases the VOCs concentration and then purifies it; for high-temperature waste gas, even if the organic concentration is low, combustion technology can also be selected. Although combustion technology is more expensive, it has a large processing capacity, good effect and a wide range of applicability; biological purification technology is currently more used in my country for the purification of odorous gases.

[0004] The VOCs waste gas generated by the petrochemical industry often contains a variety of hydrocarbon substances. These hydrocarbon substances are of various types and difficult to separate. Currently, the main treatment method is the direct combustion method. The direct combustion method directly burns VOCs as fuel, but the waste heat from combustion cannot be fully utilized. Summary of the invention

[0005] The embodiments of the present application provide a device and method for treating VOCs waste gas from a petrochemical industry to solve the technical problem that the waste heat from the combustion of VOCs waste gas from a petrochemical industry cannot be fully utilized.

[0006] In a first aspect, an embodiment of the present application provides a device for treating VOCs waste gas in a petrochemical industry, wherein the device for treating VOCs waste gas comprises:

[0007] A pretreatment system, the pretreatment system comprising a zeolite rotor and a heating unit, the zeolite rotor comprising an adsorption zone, a desorption zone and a cooling zone, the desorption zone and the cooling zone are both connected to the heating unit;

[0008] A working system, wherein the working system comprises a Stirling engine, and the desorption zone is connected to the Stirling engine.

[0009] In some embodiments of the present application, the pretreatment system further includes a filter, and the filter is connected to both the adsorption zone and the cooling zone.

[0010] In some embodiments of the present application, the filter is connected to the adsorption zone and the desorption zone via a fan.

[0011] In some embodiments of the present application, the pretreatment system further includes a buffer tank, which is connected to the filter.

[0012] In some embodiments of the present application, an exhaust port is provided on the adsorption area, and a gas composition monitoring device is provided at the exhaust port.

[0013] In some embodiments of the present application, the working system further includes a generator set, and the Stirling engine is transmission-connected to the generator set.

[0014] In some embodiments of the present application, the generator set is externally connected to a 380V power grid.

[0015] In a second aspect, an embodiment of the present application provides a method for treating VOCs waste gas in a petrochemical industry. The method is implemented by the device for treating VOCs waste gas in a petrochemical industry as described in any embodiment of the first aspect. The method comprises the following steps:

[0016] Passing the petrochemical VOCs waste gas to be treated into the adsorption zone and the desorption zone, the petrochemical VOCs waste gas is adsorbed in the adsorption zone to form purified gas and then discharged;

[0017] The petrochemical VOCs waste gas is heated in the cooling zone to form preheated gas;

[0018] Passing the preheated gas into the heating unit for heating to obtain heated gas;

[0019] Passing the heated gas into the desorption zone to desorb the organic molecules adsorbed on the zeolite wheel to obtain concentrated gas;

[0020] The concentrated gas is introduced into the Stirling engine as fuel, so that the Stirling engine performs external work.

[0021] In some embodiments of the present application, the temperature of the heating gas is not less than 200°C.

[0022] In some embodiments of the present application, the concentration of organic matter in the petrochemical VOCs waste gas is 500 to 10,000 mg / m3.

[0023] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0024] The device and method for treating petrochemical VOCs waste gas provided in the embodiment of the present application first purifies and concentrates the petrochemical VOCs waste gas through a zeolite rotor, and then uses the concentrated gas as fuel for a Stirling engine to convert its thermal energy into mechanical energy, thereby being able to fully utilize the waste heat from the combustion of the petrochemical VOCs waste gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] 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.

[0026] 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.

[0027] Figure 1 A schematic diagram of the structure of a petrochemical VOCs waste gas treatment device provided in an embodiment of the present application;

[0028] Figure 2 This is a schematic diagram of the structure of the zeolite wheel provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] 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.

[0030] Unless otherwise specified, the terms used herein should be understood as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. In the event of a conflict, this specification takes precedence.

[0031] 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.

[0032] The existing petrochemical VOCs waste gas has the technical problem that the waste heat from combustion cannot be fully utilized.

[0033] The technical solution provided by the embodiments of the present application is to solve the above technical problems, and the overall idea is as follows:

[0034] In the first aspect, the present application provides a petrochemical VOCs waste gas treatment device, please refer to Figure 1 , Figure 2 , the VOCs waste gas treatment device comprises:

[0035] A pretreatment system, the pretreatment system comprising a zeolite rotor 1 and a heating unit 2, the zeolite rotor 1 comprising an adsorption zone 11, a desorption zone 12 and a cooling zone 13, the desorption zone 12 and the cooling zone 13 are both connected to the heating unit 2;

[0036] The working system comprises a Stirling engine 3 , and the desorption zone 12 is connected to the Stirling engine 3 .

[0037] Zeolite wheel 1 is an existing mature technology. Please refer to Figure 2, the zeolite wheel 1 includes an adsorption zone 11, a desorption zone 12 and a cooling zone 13, and the blades composed of zeolite circulate and rotate in the adsorption zone 11, the desorption zone 12 and the cooling zone 13. Specifically in the present application, the petrochemical VOCs waste gas is introduced into the adsorption zone 11, and the blades will adsorb a large amount of organic molecules in the adsorption zone 11. The petrochemical VOCs waste gas in the adsorption zone 11 can be directly discharged after being adsorbed and treated to meet the emission standards; after the blades that have adsorbed a large amount of organic molecules enter the desorption zone 12, the desorption zone 12 desorbs the organic molecules from the blades through high temperature, and VOCs are enriched in the desorption zone 12, and after collection, they are further processed in the power system; after the blades have undergone high-temperature desorption, they need to be cooled to restore the adsorption capacity, so the blades that have undergone high-temperature desorption then enter the cooling zone 13 for cooling, and the cooled blades return to the adsorption zone 11 to start adsorption again.

[0038] After absorbing the heat of the blades, the temperature of the heat transfer medium in the cooling zone 13 increases. After being heated by the heating unit 2, the problem increases again. The high-temperature heat transfer medium performs high-temperature desorption treatment on the blades in the desorption zone 12.

[0039] The petrochemical VOCs waste gas can be directly introduced into the desorption zone 12 as a heat transfer medium.

[0040] The present application first purifies and concentrates the petrochemical VOCs waste gas through a zeolite rotor, and then uses the concentrated gas as fuel for a Stirling engine to convert its thermal energy into mechanical energy, thereby making full use of the combustion waste heat of the petrochemical VOCs waste gas.

[0041] In some embodiments of the present application, the pretreatment system further includes a filter 4 , and the filter 4 is connected to both the adsorption zone 11 and the cooling zone 13 .

[0042] It is easy to understand that the filter 4 is used to filter particulate matter in the petrochemical VOCs exhaust gas.

[0043] The petrochemical VOCs waste gas is directly introduced into the desorption zone 12 as a heat transfer medium. The heat transfer medium introduced into the adsorption zone 11 and the cooling zone 13 needs to be filtered first.

[0044] In some embodiments of the present application, the filter 4 is connected to the adsorption zone 11 and the desorption zone 12 via a fan.

[0045] The fan is used to drive the gas in the filter 4 to enter the cooling zone 13 and the adsorption zone 11 .

[0046] In some embodiments of the present application, the pretreatment system further includes a buffer tank 5 , and the buffer tank 5 is connected to the filter 4 .

[0047] The buffer tank 5 is used to buffer the airflow so that the petrochemical VOCs waste gas can enter the filter 4 at a relatively stable flow rate.

[0048] In some embodiments of the present application, an exhaust port is provided on the adsorption area 11, and a gas composition monitoring device is provided at the exhaust port.

[0049] After adsorption of a large number of organic molecules in the adsorption zone 11, the remaining gas is the purified gas, which is generally directly discharged. The gas composition monitoring device is used to monitor whether the purified gas meets the emission standards. The purified gas discharged must meet the requirements of GB31570-2015 and GB31571-2015, and the mass concentration of non-methane total hydrocarbons shall not exceed 120mg / m 3 , the removal efficiency is not less than 97%.

[0050] In some embodiments of the present application, the working system further includes a generator set 6 , and the Stirling engine 3 is transmission-connected to the generator set 6 .

[0051] It is easy to understand that the Stirling engine 3 performs work on the generator set 6, driving the generator set 6 to generate electricity.

[0052] In some embodiments of the present application, the generator set 6 is externally connected to a 380V power grid.

[0053] Industrial electricity is generally 380 V. The generator set 6 can be directly connected to the industrial power grid.

[0054] In a second aspect, an embodiment of the present application provides a method for treating VOCs waste gas in a petrochemical industry. The method is implemented by the device for treating VOCs waste gas in a petrochemical industry as described in any embodiment of the first aspect. The method comprises the following steps:

[0055] S1: The petrochemical VOCs waste gas to be treated is introduced into the adsorption zone 11 and the desorption zone 12, and the petrochemical VOCs waste gas is adsorbed in the adsorption zone 11 to form purified gas and is discharged;

[0056] S2: The petrochemical VOCs waste gas is heated in the cooling zone 13 to form preheated gas;

[0057] S3: passing the preheated gas into the heating unit 2 for heating to obtain heated gas;

[0058] S4: passing the heated gas into the desorption zone 12 to desorb the organic molecules adsorbed on the zeolite rotor 1 to obtain concentrated gas;

[0059] S5: introducing the concentrated gas into the Stirling engine 3 as fuel, so that the Stirling engine 3 performs external work.

[0060] In some embodiments of the present application, the temperature of the heating gas is not less than 200°C.

[0061] In some embodiments of the present application, the concentration of organic matter in the petrochemical VOCs waste gas is 500 to 10,000 mg / m3.

[0062] 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.

[0063] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present application specification, the terms "including", "comprising", etc. refer to "including but not limited to". Moreover, the terms "including", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the sentence "including..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. 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. For the association relationship of more than three associated objects described by "and / or", it means that any one of these three associated objects can exist alone, or any at least two of them exist at the same time. For example, for A, and / or B, and / or C, it can be represented that any one of A, B, and C exists alone, or any two of them exist at the same time, or three of them exist at the same time. 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, and c can be single or multiple, respectively.

[0064] 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 device for treating VOCs waste gas in petrochemical industry, characterized in that: The VOCs waste gas treatment device comprises: A pretreatment system, the pretreatment system comprising a zeolite rotor and a heating unit, the zeolite rotor comprising an adsorption zone, a desorption zone and a cooling zone, the desorption zone and the cooling zone are both connected to the heating unit; A working system, wherein the working system comprises a Stirling engine, and the desorption zone is connected to the Stirling engine.

2. The petrochemical VOCs waste gas treatment device according to claim 1, characterized in that: The pretreatment system further includes a filter, which is in communication with both the adsorption zone and the cooling zone.

3. The petrochemical VOCs waste gas treatment device according to claim 2, characterized in that: The filter is connected with the adsorption zone and the desorption zone through a fan.

4. The petrochemical VOCs waste gas treatment device according to claim 3, characterized in that: The pretreatment system further includes a buffer tank, which is in communication with the filter.

5. The petrochemical VOCs waste gas treatment device according to claim 1, characterized in that: An exhaust port is provided on the adsorption area, and a gas composition monitoring device is provided at the exhaust port.

6. The petrochemical VOCs waste gas treatment device according to claim 1, characterized in that: The working system also includes a generator set, and the Stirling engine is drivingly connected to the generator set.

7. The petrochemical VOCs waste gas treatment device according to claim 6, characterized in that: The generator set is externally connected to a 380V power grid.

8. A method for treating VOCs waste gas in petrochemical industry, characterized in that: The method is implemented by the petrochemical VOCs waste gas treatment device according to any one of claims 1 to 7, and the method comprises the following steps: Passing the petrochemical VOCs waste gas to be treated into the adsorption zone and the desorption zone, the petrochemical VOCs waste gas is adsorbed in the adsorption zone to form purified gas and then discharged; The petrochemical VOCs waste gas is heated in the cooling zone to form preheated gas; Passing the preheated gas into the heating unit for heating to obtain heated gas; Passing the heated gas into the desorption zone to desorb the organic molecules adsorbed on the zeolite wheel to obtain concentrated gas; The concentrated gas is introduced into the Stirling engine as fuel, so that the Stirling engine performs external work.

9. The method for treating petrochemical VOCs waste gas according to claim 8, characterized in that: The temperature of the heating gas is not less than 200°C.

10. The method for treating petrochemical VOCs waste gas according to claim 8, characterized in that: The concentration of organic matter in the petrochemical VOCs waste gas is 500 to 10,000 mg / m3.

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