Device and method for treating waste gas through multi-stage reverse osmosis

Abstract

The invention relates to the technical field of waste gas treatment, and discloses a device and a method for treating waste gas through multistage reverse osmosis. The device comprises a pre-filtering assembly unit (2), a first-stage treatment unit and a second-stage treatment unit, the pre-filtering assembly unit (2) comprises a coarse filter and an activated carbon filter which are communicated in sequence; the first-stage treatment unit comprises a first-stage reverse osmosis membrane (3) and a first-stage treatment container (4) which are sequentially arranged from top to bottom; and the second-stage treatment unit comprises a second-stage reverse osmosis membrane (6) and a second-stage treatment container (7) which are sequentially arranged from top to bottom. The multi-stage reverse osmosis waste gas treatment device and method provided by the invention have the characteristics of high separation efficiency and high ammonia recovery rate.

Description

Technical Field

[0001] The invention relates to the technical field of waste gas treatment, and in particular to a device and method for treating waste gas by multi-stage reverse osmosis. Background Art

[0002] In the process of industrial production, especially in the chemical, petrochemical, plastic manufacturing and electronic manufacturing industries, the emission of waste gas often contains a variety of toxic and harmful gases, such as ammonia, hydrogen sulfide, organic acids, etc. If these waste gases are directly discharged into the atmosphere without effective treatment, they will cause serious pollution to the environment and may pose a great threat to human health.

[0003] At present, waste gas treatment technologies mainly include physical adsorption, chemical absorption, biological method, thermal combustion and catalytic combustion, etc. These technologies have their own advantages and disadvantages, but they generally face major problems such as treatment efficiency, energy consumption and cost, operation and maintenance complexity, and environmental impact.

[0004] Specifically, the problem of treatment efficiency: although traditional treatment methods, such as physical adsorption and chemical absorption, can remove some pollutants in the exhaust gas, they are not effective in removing some small molecules or harmful gases with low concentrations. For example, small molecule gases such as ammonia and hydrogen sulfide are difficult to be completely adsorbed or converted due to their physical properties.

[0005] Specifically, energy consumption and cost issues: For example, although the thermal combustion method can thoroughly treat volatile organic compounds (VOCs), it usually requires high energy consumption and high operating costs, and new pollutants such as NOx may be produced during the treatment process, causing secondary pollution problems.

[0006] Specifically, operation and maintenance complexity: Many exhaust gas treatment devices require complex operating procedures and regular maintenance, which not only increases the difficulty of operation, but also increases the overall maintenance cost.

[0007] Specifically, environmental impact: Chemical treatment methods may use a large amount of chemical reagents, which themselves may be harmful to the environment, and their post-use treatment and disposal is also an environmental challenge.

[0008] In response to the above problems, the industry urgently needs a new type of waste gas treatment technology that can not only efficiently remove harmful components in the waste gas, but also be low in energy consumption, low in cost, easy to operate and maintain, and minimize the impact on the environment. Summary of the invention

[0009] The purpose of the present invention is to provide a device and method for treating waste gas by multi-stage reverse osmosis based on the above technical problems.

[0010] In order to achieve the above-mentioned object, the first aspect of the present invention provides a multi-stage reverse osmosis waste gas treatment device, the device comprising a pre-filter component unit 2, a first-stage treatment unit, and a second-stage treatment unit;

[0011] The pre-filter component unit 2 includes a coarse filter and an activated carbon filter which are connected in sequence;

[0012] The first-stage treatment unit comprises a first-stage reverse osmosis membrane 3 and a first-stage treatment container 4 arranged in sequence from top to bottom;

[0013] The second-stage treatment unit includes a second-stage reverse osmosis membrane 6 and a second-stage treatment container 7 which are arranged in sequence from top to bottom.

[0014] Preferably, in the pre-filter assembly unit 2, the average diameter of the filter pores of the filter is 0.1-1.0 μm.

[0015] Further preferably, in the first-stage treatment unit, the first-stage reverse osmosis membrane 3 is made of polyamide, and the average diameter of the membrane pores of the first-stage reverse osmosis membrane 3 is 0.1-0.4 nm.

[0016] Preferably, in the first-stage processing unit, the first-stage processing container 4 is provided with a pressure regulating mechanism.

[0017] Preferably, in the second-stage treatment unit, the second-stage reverse osmosis membrane 6 is made of polyamide, and the average diameter of the membrane pores of the second-stage reverse osmosis membrane is 0.1-0.4 nm.

[0018] Further preferably, in the second-stage processing unit, the second-stage processing container 7 is provided with a pressure regulating mechanism.

[0019] Preferably, the device also includes an air inlet 1, a first-stage air outlet 5, a second-stage air outlet 8, and a hole 9, and the air inlet 1 is arranged on the pre-filter component unit 2, the first-stage air outlet 5 is arranged on the first-stage processing container 4, and the second-stage air outlet 8 is arranged on the second-stage processing container 7.

[0020] A second aspect of the present invention provides a method for treating waste gas by multi-stage reverse osmosis, the method comprising the following steps:

[0021] (1) pre-treating waste gas containing ammonia, hydrogen sulfide, and organic acid to obtain pre-treated waste gas;

[0022] (2) The pre-treated waste gas is subjected to a first treatment and enters a compressor for compression treatment to obtain a waste gas having a concentration of 45 to 70 mg / m 3Compressed exhaust gas; the compression treatment conditions meet: no-load speed ≥ 2800r / min, air pressure 7.0 ~ 8.5Mpa;

[0023] (3) subjecting the compressed gas to a second treatment and then passing it through a detection and monitoring system to ensure compliance with environmental regulations before discharge;

[0024] The preprocessing, the first processing, the compression processing, and the second processing are performed in the device described in the first aspect of the present invention.

[0025] Preferably, in step (1), the pretreatment conditions at least meet the following conditions: temperature of 0 to 60° C. and pressure of 0.03 to 0.05 MPa.

[0026] Further preferably, in step (2), the conditions of the first treatment at least meet the following requirements: temperature of 0 to 60° C., pressure of 0.6 to 1.0 MPa, and time of 0.5 to 1.0 h.

[0027] More preferably, in step (3), the conditions of the second treatment at least meet the following requirements: temperature of 0 to 60° C., pressure of 0.6 to 1.0 MPa, and time of 0.5 to 1.0 h.

[0028] Preferably, in step (1), step (2) and step (3), the flow rate of the exhaust gas is 150-200 m / s. 3 / h.

[0029] The device and method for treating waste gas by multi-stage reverse osmosis provided by the present invention have at least the following beneficial effects:

[0030] (1) The multi-stage reverse osmosis waste gas treatment device and method of the present invention have the characteristics of high separation efficiency and high ammonia recovery rate.

[0031] (2) The method provided by the present invention has the characteristics of no secondary pollution, low energy consumption, and no need for secondary treatment of waste liquid or waste solid, so that the ammonia-containing waste gas can be circulated in a closed loop and basically achieve zero emission, thereby achieving the purpose of saving resources and protecting the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is an AA section view of a multi-stage reverse osmosis treatment device provided by the present invention;

[0033] Figure 2 It is a BB cross-sectional view of the multi-stage reverse osmosis treatment device provided by the present invention.

[0034] Description of Reference Numerals

[0035] 1. Air inlet 2. Pre-filtration component unit 3. First-stage reverse osmosis membrane

[0036] 4. First-stage processing container 5. First-stage gas outlet 6. Second-stage reverse osmosis membrane

[0037] 7. Second stage processing container 8. Second stage gas outlet 9. Hole DETAILED DESCRIPTION

[0038] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0039] The working principle and use process of the device of the present invention are as follows: First, the exhaust gas is sucked into the system through the air inlet 1 of the multi-stage reverse osmosis treatment device. Before entering the first-stage treatment unit and the second-stage treatment unit, the exhaust gas passes through a pre-filter component unit 2, which includes a coarse filter and / or an activated carbon filter for removing particulate matter, dust and other large impurities. The cleaned exhaust gas enters the first-stage treatment unit, which includes a first-stage reverse osmosis membrane for removing large molecular pollutants in the exhaust gas, such as some organic acids and heavier organic compounds.

[0040] In the present invention, the pre-filter component unit 2 is used to initially filter the exhaust gas, reduce the content of harmful compounds, and prepare for the next level of treatment.

[0041] In the present invention, a compressor is used for compression to increase the concentration of specific gas molecules in the waste gas, and to adjust the gas flow rate to optimize the efficiency of the reverse osmosis process.

[0042] In the present invention, the exhaust gas enters the second-stage treatment unit and passes through the second-stage reverse osmosis membrane 6 to remove smaller molecular harmful gases, such as ammonia and hydrogen sulfide.

[0043] In the present invention, the exhaust gas that has passed through the two-stage treatment unit is finally discharged through the first-stage outlet 5 or the second-stage outlet 8 .

[0044] The present invention will be described in detail below by way of examples. In the following examples, unless otherwise specified, the raw materials are all commercially available.

[0045] In the following examples, unless otherwise specified, the average diameter of the membrane pores in the first-stage reverse osmosis membrane 3 and the second-stage reverse osmosis membrane 6 is 0.25 nm.

[0046] Example 1

[0047] This example is used to combine Figure 1 A method for treating waste gas by multi-stage reverse osmosis is provided, and the method comprises:

[0048] (1) Connecting the exhaust gas discharge pipe to the air inlet 1 of the multi-stage reverse osmosis treatment device, turning on the switch of the multi-stage reverse osmosis treatment device to inhale the exhaust gas containing substances such as ammonia, hydrogen sulfide, and organic acid; the inhaled exhaust gas passes through the pre-filter component unit 2 (the pre-filter component unit 2 includes a coarse filter and an activated carbon filter connected in sequence), and pre-treating the exhaust gas to remove particulate matter, dust and other large impurities to obtain pre-treated exhaust gas; the pre-treatment conditions meet the following conditions: the temperature is 60°C and the pressure is 0.04MPa.

[0049] (2) The pretreated waste gas enters the first-stage treatment unit (the first-stage treatment unit includes a first-stage reverse osmosis membrane 3 and a first-stage treatment container 4 arranged in sequence from top to bottom), and is subjected to a first treatment to remove macromolecular pollutants such as organic acids and heavy organic compounds, and then enters the compressor for compression treatment to obtain a waste gas with a concentration of 45 mg / m 3 compressed exhaust gas; the first treatment conditions are met: the temperature is 50°C, in the first-stage treatment container 4, the pressure is set to 0.8MPa, and the time is 1h; the compression treatment conditions are met: the no-load speed is 2800r / min, and the air pressure is 7.0Mpa.

[0050] (3) The compressed gas enters the second-stage treatment unit (the second-stage treatment unit includes a second-stage reverse osmosis membrane 6 and a second-stage treatment container 7 arranged in sequence from top to bottom), and is subjected to a second treatment to remove small molecular pollutants such as ammonia and hydrogen sulfide, and then passes through a detection and monitoring system to ensure that it meets or exceeds environmental protection regulations, and is finally discharged from the first-stage gas outlet 5 or the second-stage gas outlet 8 (the first-stage gas outlet 5 or the second-stage gas outlet 8 is provided with an exhaust gas treatment device); the conditions for the second treatment are met: the temperature is 30°C, the pressure in the second treatment container is set to 1.0MPa, and the time is 1h.

[0051] Comparative Example 1

[0052] The process is carried out in a similar manner to that of Example 1, except that the average diameter of the membrane pores of the first-stage reverse osmosis membrane 3 is 0.05 nm, and the remaining steps and parameters are the same as those of Example 1.

[0053] Comparative Example 2

[0054] The method is similar to that of Example 1, except that the flow rate of the exhaust gas is 200 m 3 / h, and the remaining steps and parameters are the same as in Example 1.

[0055] Comparative Example 3

[0056] The process is carried out in a similar manner to that of Example 1, except that the pressure of the second treatment is 2.0 MPa, and the remaining steps and parameters are the same as those of Example 1.

[0057] Test Case

[0058] The test was conducted using a modified ammonia separation and concentration device. The waste gas came from a workshop. The odor was mainly composed of ammonia and hydrogen sulfide, with an average ammonia concentration of about 48 mg / m 3 After being treated by the membrane separation equipment, the volume fraction of ammonia gas at the first-stage outlet is about 74%, and the volume fraction of ammonia gas at the second-stage outlet is about 86%, which significantly increases the concentration and proportion of ammonia gas.

[0059] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A multi-stage reverse osmosis waste gas treatment device, characterized in that: The device comprises a pre-filtering component unit (2), a first-stage processing unit, and a second-stage processing unit; The pre-filter component unit (2) comprises a coarse filter and an activated carbon filter which are connected in sequence; The first-stage treatment unit comprises a first-stage reverse osmosis membrane (3) and a first-stage treatment container (4) which are arranged in sequence from top to bottom; The second-stage treatment unit comprises a second-stage reverse osmosis membrane (6) and a second-stage treatment container (7) which are arranged in sequence from top to bottom.

2. The device according to claim 1, wherein: In the pre-filter component unit (2), the average diameter of the filter pores of the filter is 0.1 to 1.0 μm.

3. The device according to claim 1 or 2, wherein: In the first-stage treatment unit, the first-stage reverse osmosis membrane (3) is made of polyamide, and the average diameter of the membrane pores of the first-stage reverse osmosis membrane (3) is 0.1-0.4 nm.

4. The device according to claim 1 or 2, wherein: In the first-stage processing unit, the first-stage processing container (4) is provided with a pressure regulating mechanism.

5. The device according to claim 1 or 2, wherein: In the second-stage treatment unit, the second-stage reverse osmosis membrane (6) is made of polyamide, and the average diameter of the membrane pores of the second-stage reverse osmosis membrane is 0.1-0.4 nm.

6. The device according to claim 1 or 2, wherein: In the second-stage treatment unit, the second-stage treatment container (7) is provided with a pressure regulating mechanism.

7. The device according to claim 1 or 2, wherein: The device further comprises an air inlet (1), a first-stage air outlet (5), a second-stage air outlet (8), and a hole (9), wherein the air inlet (1) is arranged on the pre-filter component unit (2), the first-stage air outlet (5) is arranged on the first-stage processing container (4), and the second-stage air outlet (8) is arranged on the second-stage processing container (7).

8. A method for treating waste gas by multi-stage reverse osmosis, characterized in that: The method comprises the following steps: (1) pre-treating waste gas containing ammonia, hydrogen sulfide, and organic acid to obtain pre-treated waste gas; (2) The pretreated waste gas is subjected to a first treatment and enters a compressor for compression treatment to obtain a waste gas containing ammonia at a concentration of 45 to 70 mg / m 3 The compressed exhaust gas; the compression treatment conditions meet: no-load speed ≥ 2800r / min, air pressure 7.0 ~ 8.5Mpa; (3) subjecting the compressed gas to a second treatment and then passing it through a detection and monitoring system to ensure compliance with environmental regulations before discharge; The preprocessing, the first processing, the compression processing, and the second processing are performed in the device described in any one of claims 1-7.

9. The method according to claim 8, wherein: In step (1), the pretreatment conditions at least meet the following conditions: temperature of 0 to 60° C. and pressure of 0.03 to 0.05 MPa; And / or, in step (2), the conditions of the first treatment at least meet the following requirements: temperature of 0 to 60° C., pressure of 0.6 to 1.0 MPa, and time of 0.5 to 1.0 h.

10. The method according to claim 8 or 9, wherein: In step (3), the conditions of the second treatment at least meet the following requirements: temperature of 0 to 60°C, pressure of 0.6 to 1.0 MPa, and time of 0.5 to 1.0 h; And / or, in step (1), step (2), and step (3), the flow rate of the exhaust gas is 150 to 200 m / s. 3 / h.

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