TWI679058B - Gas purification-concentration system and method for regenerating filter material - Google Patents

Abstract

The invention provides a gas purification and concentration system capable of concentrating exhaust gas containing alkaline compounds, comprising: an acid washing tower; a regeneration purification device connected to the acid washing tower, wherein the regeneration purification device is provided with a filter material for purifying the exhaust The alkaline compound is concentrated and reused, and the filter material can be reused; and an alkaline washing tower is connected to the regeneration purification device. The invention also provides a method for regenerating a filter medium.

Description

Gas purification and concentration system and regeneration method of filter material

The present invention relates to a gas purification system, and more particularly to a gas purification and concentration system capable of purifying alkaline compounds in a gas and regenerating a filter material (adsorbent).

In current waste gas treatment systems, incineration, washing or adsorption can remove low-threshold malodorous substances. Incineration technology is mainly used for the removal of medium and high concentrations of organic matter, and is less suitable for low-threshold malodorous substances. Although it can be achieved with a concentration system, it is not economical. Although the washing method can reduce the concentration of low-threshold malodorous substances in the exhaust gas, it cannot be completely removed due to the limitation of gas and liquid distribution and processing temperature. The adsorption system has excellent removal effect for low-concentration pollutants, but its effective adsorption amount will decrease as the concentration of pollutants decreases. Some special structured pollutants can be chemically adsorbed by modified adsorbents. Their adsorption amount is less affected by the concentration of pollutants, but the price of modified adsorbents is higher than that of general adsorbents, and the expenditure on consumable costs will also be increase. Therefore, it is necessary to use an online regeneration system for the regeneration of the adsorbent (filter material), which can not only reduce the cost of purchasing consumables, but also reduce the amount of waste. It is in line with the concept of recycling and is an environmentally friendly technology.

Therefore, it is desirable to develop a gas purification and concentration system that can purify alkaline compounds (low-threshold malodorous substances) in gas and regenerate filter media (adsorbent).

According to an embodiment of the present invention, a gas purification and concentration system is provided, including: a pickling tower; and a regeneration-purification device connected to the pickling tower, wherein the regeneration purification device is provided with a filter material for To purify the alkaline compounds in the exhaust gas, and the filter material can be reused; and an alkaline washing tower, which is connected to the regeneration purification device.

In some embodiments, the washing liquid of the pickling tower includes sulfuric acid. In some embodiments, the basic compound includes an inorganic base or an organic base. In some embodiments, the basic compound includes 3-methylpyridine. In some embodiments, the concentration of the basic compound is between 1 and 200 ppm. In some embodiments, the filter material includes a porous adsorbent material. In some embodiments, the filter material includes activated carbon, alumina, or zeolite. In some embodiments, the washing liquid of the alkaline washing tower includes sodium hydroxide.

According to an embodiment of the present invention, a method for regenerating a filter medium is provided, including: providing the above-mentioned gas purification and concentration system, and performing a cleaning step on the filter medium in the regeneration and purification device; and performing an impregnation step on the filter medium with strong acid. .

In some embodiments, the cleaning step is to clean the filter medium with water. In some embodiments, the cleaning step includes single cleaning, multiple cleanings, or soaking. In some embodiments, the operation time of the cleaning step is between 20-60 minutes. In some embodiments, the method for regenerating the filter medium of the present invention further includes recovering the concentrated liquid containing the basic compound discharged from the regeneration purification device after the cleaning step.

In some embodiments, the impregnation step includes washing or soaking. In some embodiments, the operation time of the impregnation step is between 5-30 minutes. In some embodiments, the strong acid includes sulfuric acid. In some embodiments, the concentration of the strong acid is between 1-3M. In some embodiments, the method for regenerating the filter medium of the present invention further includes discharging the concentrated solution containing the basic compound and the strong acid from the regeneration purification device by gravity, pressure, or aeration. In some embodiments, the method for regenerating the filter medium of the present invention further includes recovering the concentrated liquid containing the basic compound and the strong acid discharged from the regeneration purification device.

The invention can be applied to purify exhaust gas containing basic compounds and concentrate the basic compounds for reuse. Furthermore, the used filter material can be reused through simple online regeneration procedures and devices. By the process design of the present invention, the gas blowing-out process can be eliminated, which can avoid secondary pollution caused by gas blowing-out and the increased exhaust air volume due to the blowing-out (dry) process. The effects achieved by the present invention are as follows: (1) the filter material regeneration processing step can be simplified, and the blowing (drying) process is not required, which effectively reduces the operating cost and operating time; (2) the odorous substances caused by the blowing (drying) process can be avoided Escape, and (3) low-value valuable basic compounds can be concentrated and reused to achieve the purpose of circular economy and green process.

Referring to FIG. 1, a gas purification-concentration system 10 is provided according to an embodiment of the present invention. FIG. 1 is a schematic diagram of a gas purification and concentration system 10.

The gas purification and concentration system 10 includes an acid washing tower 12, a regeneration-purification device 14, and an alkali washing tower 16. The regeneration purification device 14 is connected to the pickling tower 12. The alkali washing tower 16 is connected to the regeneration purification device 14. It is worth noting that a filter material 18 is provided in the regeneration purification device 14 to purify alkaline compounds in the exhaust gas, and the filter material 18 can be recycled for use. The order of acid pickling tower and alkaline washing tower in this embodiment cannot be adjusted. The gas containing acid and basic compounds must pass through the acid washing tower and the regeneration purification device before entering the alkali washing tower. Carrying an alkaline-containing compound into the regeneration purification device causes the effect of the filter medium 18 to be reduced.

In some embodiments, the washing liquid of the acid washing tower 12 may include various strong acid solutions, such as sulfuric acid with a concentration of 35-38%. In some embodiments, the basic compound in the exhaust gas may include an inorganic base or an organic base, the inorganic base may include ammonia, and the organic base may include an amine or a nitrogen-containing heterocyclic compound. In some embodiments, the basic compound in the exhaust gas may include, for example, pyridine, imidazole, methylamine, benzimidazole, or a combination thereof. In some embodiments, the basic compound in the exhaust gas may include, for example, 3-picoline or dimethylamine. In some embodiments, the concentration of the basic compound in the exhaust gas is approximately 1-200 ppm. In some embodiments, the filter material 18 provided in the regeneration purification device 14 may include a porous adsorbent material, such as activated carbon, alumina, or zeolite. In some embodiments, the washing liquid of the alkali washing tower 16 may include various strong alkali solutions, such as sodium hydroxide and the like. In some embodiments, the hole size of the filter material 18 is between about 1 and 300 angstroms (Å). If the pore size of the filter medium 18 is too small, exhaust gas molecules cannot enter, and basic compounds in the exhaust gas cannot be adsorbed. If the size of the pores of the filter medium 18 is too large, the exhaust gas molecules can easily penetrate the pores of the filter medium 18 and reduce the adsorption effect.

Referring to FIG. 2, according to an embodiment of the present invention, a regeneration method 100 for a filter medium is provided. FIG. 2 is a schematic flowchart of a method 100 for regenerating a filter medium.

Referring to FIG. 1 at the same time, first, the filter material 18 provided in the regeneration purification device 14 is cleaned in step 102, and the alkaline compound adhering to the surface of the filter material 18 is washed and eluted.

In some embodiments, in the cleaning step 102, the filter medium 18 is washed with water. In some embodiments, the cleaning step 102 may include single cleaning, multiple cleaning, or soaking. In some embodiments, the amount of water used to clean the filter medium 18 is approximately 2-10 times the volume of the filter medium 18. In some embodiments, the amount of water used to clean the filter medium 18 is approximately 5-10 times the volume of the filter medium 18. In some embodiments, the operation time of the cleaning step 102 is about 20-60 minutes. In some embodiments, the method 100 for regenerating the filter medium of the present invention further includes a recovery step 106 after the cleaning step 102, for example, recovering the concentrated solution containing the alkaline compound discharged from the regeneration purification device 14.

After that, the filter medium 18 is impregnated with a strong acid 104.

In some embodiments, the impregnation step 104 may include washing or soaking. In some embodiments, the impregnation step 104 may include a single immersion or multiple cyclic immersion, and the adjustment depends on a reasonable amount of water. In some embodiments, the operation time of the impregnation step 104 is about 1-120 minutes. In some embodiments, the operation time of the impregnation step 104 is about 5-30 minutes. In some embodiments, the operation time of the impregnation step 104 is about 10-30 minutes. In some embodiments, the strong acid used in the impregnation step 104 may include a strong acid having a pH of less than 3, such as sulfuric acid. In some embodiments, the concentration of the strong acid used in the impregnation step 104 is about 1-3M. In some embodiments, the concentration of the strong acid used in the impregnation step 104 is about 2-3M. In some embodiments, the amount of strong acid in the impregnation step 104 only needs to cover the filter material 18. In some embodiments, the method 100 for regenerating the filter medium of the present invention further includes discharging a concentrated solution containing a basic compound and a strong acid from the regeneration purification device 14 by gravity, pressure, or aeration (not shown). In some embodiments, the method 100 for regenerating the filter medium of the present invention further includes a recovery step 108 after the impregnation step 104, for example, recovering a concentrated solution containing a basic compound and a strong acid discharged from the regeneration purification device 14. At this point, the filter material 18 after the impregnation step 104 and the concentrated liquid is discharged can be reused, and it can be continuously applied to the subsequent exhaust gas treatment step 110 without drying the impregnated filter material 18 for a long time.

Please refer to FIG. 3, according to an embodiment of the present invention, a method 1000 for purifying a gas is provided. FIG. 3 is a schematic diagram of a gas purification method 1000.

First, the exhaust gas 1200 is introduced into the pickling tower 12 to wash out basic compounds in the exhaust gas 1200. The content of the exhaust gas 1200 includes 50-200 ppm of basic compounds (such as 3-methylpyridine), 1-100 ppm of acidic compounds, and 1-10 ppm of volatile organic compounds (VOCs). In some embodiments, the washing liquid of the acid washing tower 12 may include various strong acid solutions, such as sulfuric acid and the like.

After the exhaust gas 1200 passes through the pickling step of the pickling tower 12, a first exhaust gas 1400 and a first eluate 1600 are generated. The contents of the first exhaust gas 1400 include 1-2 ppm of a basic compound (such as 3-methylpyridine), 1-100 ppm of an acidic compound, and 1-10 ppm of a volatile organic compound. The first eluate 1600 contains a high concentration of a basic compound (such as 3-methylpyridine). After that, the first exhaust gas 1400 is introduced into the regeneration purification device 14 provided with the filter material 18 therein to perform purification of the first exhaust gas 1400, and the first eluate 1600 is introduced into the alkaline compound recovery and regeneration system 1800. In order to recover and reuse basic compounds (for example, 3-methylpyridine). In some embodiments, the filter material 18 provided in the regeneration purification device 14 may include a porous adsorbent material, such as activated carbon, alumina, or zeolite.

After the first exhaust gas 1400 undergoes the purification step of the regeneration purification device 14, a second exhaust gas 2000 is generated. After that, after the above-mentioned regeneration method of the filter medium, a second eluate 2200 is generated. The contents of the second exhaust gas 2000 include 1-100 ppm of acidic compounds and 1-10 ppm of volatile organic compounds. The second eluate 2200 contains a high concentration of a basic compound (such as 3-methylpyridine). In some embodiments, the concentration of the alkaline compound in the second eluate 2200 is about 1-2 wt% or more, which means that after the first exhaust gas 1400 has been purified by the regeneration purification device 14, the alkaline compound has been removed. The concentration is concentrated from 1-2ppm to 1-2wt% or more (the concentration ratio is more than 1,000 times). It is worth noting that the second exhaust gas 2000 at this time has no residual of basic compounds (such as 3-methylpyridine). After that, the second exhaust gas 2000 is introduced into the alkali washing tower 16 to wash out the acidic compounds in the second exhaust gas 2000, and the second eluate 2200 is introduced into the alkaline compound recovery and regeneration system 1800 to perform the alkaline compounds. (For example, 3-methylpyridine). In some embodiments, the washing liquid of the alkali washing tower 16 may include various strong alkali solutions, such as sodium hydroxide and the like.

After the second exhaust gas 2000 passes through the alkali washing step of the alkali washing tower 16, a third exhaust gas 2400 is generated. The content of the third exhaust gas 2400 includes 0.1-1 ppm of acidic compounds and 1-10 ppm of volatile organic compounds. At this time, the third exhaust gas 2400 has no residual of a basic compound (for example, 3-methylpyridine), and contains only a low-concentration acidic compound. At this point, the purification of the exhaust gas 1200 is completed.

The invention can be applied to purify exhaust gas containing basic compounds and concentrate the basic compounds for reuse. Furthermore, the used filter material can be reused through simple online regeneration procedures and devices. By the process design of the present invention, the gas blowing-out process can be eliminated, which can avoid secondary pollution caused by gas blowing-out and the increased exhaust air volume due to the blowing-out (dry) process. The effects achieved by the present invention are as follows: (1) the filter material regeneration processing step can be simplified, and the blowing (drying) process is not required, which effectively reduces the operating cost and operating time; (2) the odorous substances caused by the blowing (drying) process can be avoided Escape, and (3) low-value valuable basic compounds can be concentrated and reused to achieve the purpose of circular economy and green process.

Examples / Comparative Examples

The invention conducts the adsorption treatment capacity test of the filter material. The diameter and length of the adsorption bed reactor are 2.0cm and 30cm respectively, the adsorption temperature is 25 ° C, and the inflow gas is controlled by a float flow meter. . Alkali pollutants were tested with 3-methylpyridine (C6H7N (CAS: 108-99-6), threshold is 0.02ppm) and dimethylamine. The concentration of 3-methylpyridine and dimethylamine was aerated. (The temperature of the water bath is controlled at 20 ° C), and then diluted with air to adjust it. When the adsorption experiment is performed, the concentration of the alkaline exhaust gas flowing in and out is analyzed by a hydrocarbon analyzer.

Dimethylamine removal efficiency test:

Take 20 grams of filter material to treat dimethylamine-containing exhaust gas. The dimethylamine concentration at the inlet is 125 units displayed by a hydrocarbon analyzer, the total gas flow is 8.0L / min, and the relative air humidity is 80% (25 ° C) After 8 hours of testing, the concentration of dimethylamine at the outlet is 0 units displayed by the hydrocarbon analyzer, and the removal rate is greater than 99%, indicating that this filter material can effectively treat the basic compound dimethylamine.

Saturation adsorption test:

Take 20 grams of filter material to treat 3-methylpyridine-containing exhaust gas. The concentration of 3-methylpyridine is 200ppm, the total gas flow is 7.8L / min, and the relative humidity of the air is 80% (25 ° C). After the concentration of methylpyridine is greater than 180 ppm, the test is stopped, and the amount of 3-methylpyridine processed per unit filter medium is calculated.

Example 1

2 Step regeneration and low concentration 3- Methylpyridine exhaust gas treatment test

(1) Washing step: Rinse the deionized water with 10 times the volume of the filter medium from the upper end of the adsorption column, and the washing concentrate flowing out has the taste of 3-methylpyridine, and the pH of the solution is about 2.

(2) Impregnation step: add 60ml of sulfuric acid solution (1M), soak for 2 minutes, after discharge, the concentration of 3-methylpyridine in the tail gas is about 0-1ppm (analysis by detection tube), and then add 40ml of sulfuric acid solution (3M), soak for 15 minutes. After draining, the concentration of 3-methylpyridine tube in the tail gas is 0 ppm (no discoloration in the tube analysis).

After the 2-stage regeneration process, the filter material continued to treat 3-methylpyridine-containing exhaust gas. The concentration of 3-methylpyridine was 5 ppm, the total gas flow was 7.8L / min, and the relative air humidity was 80% (25 ° C ), After the concentration of 3-methylpyridine in the tail gas is greater than 4.5 ppm, the test may be stopped, and the amount of 3-methylpyridine processed per unit filter medium is calculated. The results are shown in Table 1 below.

Comparative Example 1

4 Step regeneration and high concentration 3- Methylpyridine exhaust gas treatment test

When the filter material is saturated, stop the test and regenerate the filter material. The regeneration procedure and analysis are as follows:

(1) Washing step: Rinse the deionized water with 10 times the volume of the filter medium from the upper end of the adsorption column, and the washing concentrate flowing out has the taste of 3-methylpyridine, and the pH of the solution is about 2.

(2) Blowing out step: Use laboratory outside air for blowing out (25 ° C, RH ~ 65%), 6L / min. After 8 hours of blowing out, after the filter material weight change is less than 0.1 g, stop blowing out and impregnate step.

(3) Impregnation step: pour 3M sulfuric acid (H ₂ SO ₄ ) impregnation solution into the filter tube column after blowing out, cover the filter material with the solution, and let it stand for 30 minutes before draining the solution.

(4) Blowing out step: blow off with outside air at 6L / min for 2 hours and set aside.

After adding 250ml of deionized water to the cleaning section for cleaning, the concentration of 3-methylpyridine in the tail gas is about 2ppm when the filter material is blown out by outside air (detection tube analysis), and then add 150ml of deionized water (400ml in total) During cleaning, the concentration of 3-methylpyridine in the tail gas is still about 2 ppm (detection tube analysis), which indicates that the blowing-out step after cleaning will cause 3-methylpyridine to escape again from the filter material, causing Secondary pollution.

The 4-stage regeneration filter was used to treat 3-methylpyridine-containing exhaust gas. The concentration of 3-methylpyridine was 200 ppm, the total gas flow was 7.8L / min, and the relative air humidity was 80% (25 ° C). After the concentration of 3-methylpyridine in the exhaust gas is greater than 180 ppm, the test can be stopped and the amount of 3-methylpyridine processed per unit filter medium can be calculated. The results are shown in Table 1 below.

Comparative Example 2

4 Step regeneration and low concentration 3- Methylpyridine exhaust gas treatment test

The regeneration treatment procedure is the same as that of Comparative Example 1, except that the compressed and dried air (25 ° C, RH <10%) is blown out for 6 hours at 6 L / min instead of outside air, and then an impregnation step is performed. When purged, the concentration of 3-methylpyridine in the tail gas was still about 2 ppm (detection tube analysis). The 4-stage regenerated filter material that was blown out with compressed dry air was tested for 3-methylpyridine exhaust gas. During the exhaust gas test, the concentration of 3-methylpyridine was 5 ppm and the concentration of 3-methylpyridine in the tail gas was greater than 4.5 After ppm, the test can be stopped and the amount of 3-methylpyridine processed per unit of filter material can be calculated. The results are shown in Table 1 below. Table 1. Differences in the treatment of 3-methylpyridine-containing waste gas by different regeneration methods Filter material Fresh filter Comparative Example 1 (4-stage recycled filter media) Comparative Example 2 (4-stage recycled filter media) Example 1 (2-stage regeneration filter) 3-methylpyridine concentration (ppm) 200 200 5 5 3-methylpyridine removal rate (%) ＞ 99 ＞ 99 ＞ 99 ＞ 99 Breakthrough processing capacity (wt%) twenty one ＞ 21 ＞ 21 ＞ 21 Estimated AP content in cleaning concentrates * 1% 1% 1% 1% Estimated concentration ratio - - 2000 2000 Blow-off condition - Exhaust air (25-26 ℃, RH = 65-75%) for 8 hours (6L / min) Compressed dry air (25-26 ℃, RH ＜ 10%) blown off for 1 hour (6L / min) No blow-off (drain) When blowing off, the concentration of 3-methylpyridine in the tail gas - 1-2ppm 1-2ppm not detected Filter material: 20 grams; calculated processing quantity when the throughput is C / C0 = 0.05; 3-methylpyridine concentration is analyzed using a detection tube. * Approximately 4 grams of AP (20%) is adsorbed with 20 grams of filter material, and washed. Liquid is about 400 grams

The features of the above-mentioned embodiments are beneficial to those skilled in the art to understand the present invention. Those of ordinary skill in the art should understand that the present invention can be used as a basis for designing and changing other processes and structures to achieve the same purpose and / or the same advantages of the above embodiments. Those with ordinary knowledge in the technical field should also understand that these equivalent replacements do not depart from the spirit and scope of the present invention, and can be changed, replaced, or changed without departing from the spirit and scope of the present invention.

10‧‧‧Gas purification system

12‧‧‧Pickling tower

14‧‧‧ regeneration purification device

16‧‧‧ Alkali washing tower

18‧‧‧ Filter media

100‧‧‧ Filter material regeneration method

102‧‧‧Cleaning steps

140‧‧‧ Impregnation steps

106, 108‧‧‧ Recovery steps

110‧‧‧Exhaust gas treatment steps

1000‧‧‧ gas purification method

1200‧‧‧ exhaust gas

1400‧‧‧First exhaust gas

1600‧‧‧The first eluent

1800‧‧‧ Alkaline Compound Recovery System

2000‧‧‧Second exhaust gas

2200‧‧‧Second eluate

2400‧‧‧Third exhaust gas

FIG. 1 is a schematic diagram of a gas purification and concentration system according to an embodiment of the present invention; and FIG. 2 is a schematic flowchart of a regeneration method of a filter medium according to an embodiment of the present invention; and FIG. A schematic flow chart of a gas purification method.

Claims (19)

A gas purification and concentration system includes: a pickling tower for introducing unpurified exhaust gas; and a regeneration purification device connected to the pickling tower, wherein the regeneration purification device is provided with a filter material for purifying alkaline compounds in the exhaust gas, And the filter material can be reused; and an alkaline washing tower is connected with the regeneration purification device to introduce the gas generated by the regeneration purification device. The gas purification and concentration system according to item 1 of the patent application scope, wherein the washing liquid of the acid washing tower comprises sulfuric acid. The gas purification and concentration system according to item 1 of the patent application scope, wherein the basic compound includes an inorganic base or an organic base. The gas purification and concentration system according to item 3 of the patent application scope, wherein the basic compound includes 3-methylpyridine or dimethylamine. The gas purification and concentration system according to item 1 of the scope of patent application, wherein the concentration of the basic compound is between 1 and 200 ppm. The gas purification and concentration system according to item 1 of the patent application scope, wherein the filter medium includes a porous adsorbent material. The gas purification and concentration system according to item 6 of the patent application scope, wherein the filter medium comprises activated carbon, alumina, or zeolite. The gas purification and concentration system according to item 1 of the scope of patent application, wherein the washing liquid of the alkali washing tower comprises sodium hydroxide. A method for regenerating a filter medium includes: providing a gas purification and concentration system as described in item 1 of the scope of patent application, and performing a cleaning step on the filter medium in the regeneration and purification device; and performing an impregnation step on the filter medium with strong acid. The method for regenerating a filter medium according to item 9 of the scope of the patent application, wherein the cleaning step is to clean the filter medium with water. The method for regenerating the filter medium according to item 9 of the scope of the patent application, wherein the cleaning step includes single cleaning, multiple cleanings, or soaking. The method for regenerating the filter medium according to item 9 of the scope of the patent application, wherein the operation time of the cleaning step is between 20-60 minutes. The method for regenerating the filter medium according to item 9 of the scope of the patent application, further comprises, after the washing step, recovering the concentrated liquid containing the basic compound discharged from the regeneration purification device. The method for regenerating a filter medium according to item 9 of the patent application scope, wherein the impregnation step includes washing or soaking. The method for regenerating the filter medium according to item 9 of the scope of the patent application, wherein the operation time of the impregnation step is between 5-30 minutes. The method for regenerating a filter medium according to item 9 of the patent application scope, wherein the strong acid comprises sulfuric acid. The method for regenerating a filter medium according to item 9 of the scope of application for a patent, wherein the concentration of the strong acid is between 1-3M. The method for regenerating the filter medium according to item 9 of the scope of the patent application, further comprises discharging the concentrated solution containing the basic compound and the strong acid from the regeneration purification device by gravity, pressure, or aeration. The method for regenerating the filter medium according to item 18 of the scope of application for patent, further comprising recovering the concentrated liquid containing the basic compound and the strong acid discharged from the regeneration purification device.