CN111804269A

CN111804269A - Filter screen for removing harmful gas

Info

Publication number: CN111804269A
Application number: CN202010460428.XA
Authority: CN
Inventors: 张世著; 金鹏翔; 张志雄; 童宁军; 石欣超; 张将
Original assignee: Nanjing Yunxiang Nanotechnology Co ltd
Current assignee: Nanjing Yunxiang Nanotechnology Co ltd
Priority date: 2020-05-09
Filing date: 2020-05-26
Publication date: 2020-10-23

Abstract

The invention relates to a filter screen for removing harmful gas. A filter screen for removing harmful gas is composed of a net structure and permanganate type inorganic particles. Cylindrical permanganate type inorganic particles with high mechanical strength are prepared by adopting an extrusion granulation process, and are combined with a net structure in a hot melting mode through hot melt adhesives. The raw materials selected by the invention have low cost and simple production process, are suitable for large-scale production and manufacture, and have considerable efficiency for removing harmful gases, particularly formaldehyde.

Description

Filter screen for removing harmful gas

Technical Field

The invention belongs to the field of air purification, and particularly relates to a filter screen for removing harmful gases.

Background

The removal of harmful gases is mainly achieved by two technologies, physical adsorption and chemical adsorption. Physisorption and chemisorption are not isolated and often occur concomitantly. Physical adsorption is an adsorption phenomenon that an adsorbent and an adsorbate are mutually attracted through intermolecular force (van der waals force), generally has no selectivity, small acting force and reversible process, namely, adsorbed gas molecules are easy to desorb (desorb). In contrast, chemisorption is the result of a chemical reaction between the adsorbent surface and the adsorbate, a process that is selective and irreversible.

At present, the most commonly used harmful gas removal medium is activated carbon, which is a common non-polar adsorbent and can adsorb most organic gases, such as benzenes, aldehydes and ketones, alcohols, hydrocarbons and the like, and malodorous substances; however, since the adsorption mechanism of activated carbon is physical adsorption, toxic and harmful malodorous gases cannot be completely removed, and activated carbon is flammable and is not suitable for use as a base material for an oxidation reaction type chemical adsorption process that generates heat. Therefore, a harmful gas removing medium using a non-toxic and harmless porous material (such as activated alumina or the like) as a base material has been a major point of research and development.

At present, a harmful gas removal medium taking a non-toxic and harmless porous material as a base material is mainly manufactured by a disc granulation method, for example, in a U.S. patent 'US 6004522Solid filtration media in relating to evaporation levels of permanato and water', alumina is adopted as the base material, 7-12 wt% of potassium permanganate and 10-35 wt% of water are added, and a Solid filtration medium is manufactured by a process of spraying a mixture of the alumina and sodium bicarbonate by a heated aqueous potassium permanganate solution and synchronously granulating; in the chinese patent "CN 200380104041.5 high capacity solid filter medium", 13-25 wt% of permanganate (including potassium permanganate, sodium permanganate, magnesium permanganate, barium permanganate, lithium permanganate or a combination thereof) is used, and the solid filter medium is manufactured by a process of spraying alumina with a heated aqueous permanganate solution and synchronously granulating. But the disc granulation method has low granulation efficiency, low granulation ratio (granulation success rate) and low mechanical strength of the produced granules; and the produced particles are spherical, so that long-term combination and effective application of the particles with a filter screen type filter in the air purification industry are difficult to realize, and the particles can only be applied to old filter material cylinders and bag type filters in the form of filter material bags, so that the accumulation of the particles is caused, the reaction contact area between a harmful gas removal medium and the harmful gas is reduced, and the treatment efficiency of the harmful gas is further reduced. The defects greatly limit the popularization and application of the disc granulation method in the production and manufacture of harmful gas removal medium particles.

Extrusion granulation has also been used to produce harmful gas removal Media due to its advantages of high granulation efficiency, high granulation ratio (granulation success rate), high mechanical strength of the produced granules, and adjustable morphology, such as in U.S. Pat. No. US20150182945a1 Dry-scattering Media Compositions and Methods of production and Use, in which activated alumina, magnesia, and activated carbon are mixed in water and the mixture is extruded through a die to form a substrate or honeycomb structure having long open channels, and the adsorption efficiency is greatly improved while the structural strength is improved. However, the granules prepared by the extrusion granulation method are difficult to form holes penetrating through the granules as places for contact reaction with harmful gases, and the porosity of the granules is low, so that the requirements of the air purification industry on harmful gas removal media cannot be met, and the granules are not continuously applied, and corresponding research is in a stagnant state.

Therefore, finding a harmful gas removing medium which is prepared by an extrusion granulation method and has high porosity and through holes inside, realizing high-efficiency combination with a common net structure and finally efficiently removing harmful gas becomes a core problem to be solved urgently for the development of the air purification industry. And the structure of the filter screen has a foreseeable wide prospect in the aspects of long-acting sterilization, dehumidification and the like in the air purification industry.

Disclosure of Invention

The invention provides a filter screen for removing harmful gases, which prepares cylindrical permanganate type inorganic particles with high mechanical strength by adopting an extrusion granulation process; the mechanical strength of the prepared harmful gas removal medium is further improved by adding a mixture of silicate cement and calcium hydroxide as a binder to the permanganate type inorganic particles, by adding bicarbonate (for example, sodium bicarbonate) or aluminum powder as a foaming agent to the permanganate type inorganic particles to increase the porosity of the prepared harmful gas removal medium and to produce an appropriate amount of pores that pass through the interior of the harmful gas removal medium. The raw materials selected by the invention have low cost and simple production process, are suitable for large-scale production and manufacture, and have considerable efficiency of removing harmful gases (particularly formaldehyde).

The invention discloses a filter screen for removing harmful gases, which consists of a net structure and permanganate type inorganic particles. The permanganate type inorganic particles are attached to the network structure. The permanganate type inorganic particles form a manganate type inorganic particle layer.

The permanganate type inorganic particles are combined with the net structure in a hot melting mode through hot melt adhesives. There are hot-melt connection points between the permanganate type inorganic particles and the network structure.

Further, the material of the net-shaped structure is one or more of metal, inorganic material and organic material, wherein the organic material is preferred, and the material is more preferred to be PET or PP.

The net structure is a quasi-circular net (holes are quasi-circular).

Further, the permanganate type inorganic particles comprise one or more of crystals of the manganite, activated carbon particles containing a permanganate solution and activated alumina particles containing a permanganate solution, and preferably activated alumina particles containing a sodium permanganate solution;

further, the activated alumina particles containing the sodium permanganate solution comprise the following components in percentage by weight: 4-12 wt% of sodium permanganate, 8-20 wt% of water, 50-65 wt% of activated alumina and 12-30 wt% of binder;

further, the activated alumina particles containing the sodium permanganate solution further comprise 8-20 wt% of a foaming agent, wherein the foaming agent is one or a combination of two of bicarbonate and aluminum powder in any proportion, and bicarbonate is preferred.

Further, the binder is a combination of one or two of hydroxide or alkaline oxide and cement; the cement is one or a combination of more of silicate cement, aluminate cement or phosphate cement, the hydroxide is calcium hydroxide, and the alkaline oxide is calcium oxide. The preferred cement is a silicate cement.

Further, the binder is a mixture of silicate cement and calcium hydroxide, and comprises the following components in percentage by weight: 12-24 wt% of silicate cement and 76-88 wt% of calcium hydroxide.

Further, the particles are cylindrical particles. Furthermore, the mesh number of the activated alumina is 80-325;

furthermore, the diameter of the prepared cylindrical particle is 1-5 mm, and the ratio of the length to the diameter is 1: 20-20: 1; is prepared by an extrusion granulation process.

Furthermore, the porosity of the activated alumina particles containing the sodium permanganate solution is 10-40%, and preferably 15-30%.

Further, the specific preparation process of the activated alumina particles containing the sodium permanganate solution comprises the following steps:

1) comprises the following components in percentage by weight: 4-12 wt% of sodium permanganate, 8-20 wt% of water, 50-65 wt% of activated alumina and 12-30 wt% of binder are fully mixed to obtain a mixture;

2) preparing the mixture prepared in the step 1) into granules by an extrusion granulator;

3) curing the particles obtained in the step 2) until the water content of the solid particles is 12-17%; the particles are cylindrical particles. Furthermore, the mesh number of the activated alumina is 80-325;

furthermore, the hot melt adhesive is EVA hot melt adhesive TPR hot melt adhesive, PA hot melt adhesive, PES hot melt adhesive, PE hot melt adhesive, PEA hot melt adhesive and reaction type hot melt adhesive, and the hot melt mode is that under the condition of 60-150 ℃, the hot melt adhesive is firstly bonded on the net grid of the net structure through a roller gluing machine or a spraying machine, and then the permanganate type inorganic particles are bonded on the net grid of the net structure bonded with the hot melt adhesive in a pressing mode.

Advantageous effects

The filter screen for removing harmful gas 1 consists of a net-shaped structure and permanganate type inorganic particles, the permanganate type inorganic particles are attached to the net-shaped structure, the structure and the harmful gas to be treated are large in area, long in service life, low in cost and good in adsorption effect.

2, the activated alumina containing the sodium permanganate solution is used as the permanganate type inorganic particles, so that the mechanical strength and the adsorption efficiency are ensured, and the safety is also ensured; meanwhile, the used raw materials have low cost and are beneficial to large-scale production and manufacture;

3, the diameter of the cylindrical particles prepared by the extrusion granulation method is 1-5 mm, and the length is preferably in the same order of magnitude as the diameter, so that the mechanical strength is ensured, an air passage penetrating through the inside of the cylindrical particles is also ensured, and an enough surface area is provided for the hot melting combination with a reticular structure; the active alumina particles of the sodium permanganate solution with the porosity of 10-40%, preferably 15-30%, can produce a good adsorption effect, and meanwhile, the mechanical strength is good.

4 the material is a similar circular net of PET or PP, the cost is low, and the processing and cutting are easy, which is beneficial to the use of air purification equipment of various types and occasions.

Drawings

Fig. 1 is a schematic view of a net structure in a filter net for removing harmful gas.

FIG. 2 is a schematic view of a cross-sectional structure of a filter screen for removing harmful gases

Fig. 3 is a partial enlarged structure view of a cross section of a filter screen for removing harmful gas.

1-permanganate type inorganic particle layer; 2-hot-melt connection points; 3-mesh structure, 4-round hole;

Detailed Description

The first embodiment is as follows:

referring to the raw material ratio in CN 201910547521.1-harmful gas removing medium and preparation method thereof, 510g of active alumina and NaHCO are mixed₃160g of a binder consisting of 130g of 15 wt% of silicate cement and 85 wt% of calcium hydroxide and 300ml (369g) of 27.6 wt% of sodium permanganate aqueous solution are mixed to prepare a powder, and then the powder is prepared into cylindrical particles with the diameter of 2mm and the length of 2mm by an extrusion granulation mode. The prepared particles are stood for 12 hours at room temperature, and then are solidified for 1.8 hours at the high temperature of 110 ℃ until the water content of the solid particles is 17 percent, and the medium for removing harmful gases containing 10 percent by weight of sodium permanganate is obtained.

Example two:

preparation of a harmful gas-removing medium containing 12 wt% of sodium permanganate the medium was prepared in the same manner as in example one except that the sodium permanganate content was changed by spraying 300ml (369g) of a 27.6 wt% aqueous solution of sodium permanganate onto the mixture.

Example three:

preparation of harmful gas removal Medium containing 8 wt% sodium permanganate

The preparation was carried out as in example one, except that the sodium permanganate content was changed by spraying 300ml (355g) of 23.1 wt% aqueous sodium permanganate solution onto the mixture.

Example four:

preparation of harmful gas removal Medium containing 6 wt% sodium permanganate

The preparation was carried out as in example one, with the sodium permanganate content being varied, i.e. 300ml (342g) of an aqueous 18.1% strength by weight sodium permanganate solution were sprayed onto the mixture.

The products of the 4 examples described above were subjected to performance measurements

The standard accelerated test method for measuring the capacity of the harmful gas removal medium is adopted in Chinese patent CN200380104041.5 high-capacity solid filter medium, and comprises the following steps:

testing of the filter media typically takes a relatively long time to obtain results due to the low concentration of contaminated air supply, and the following method provides an accelerated test of the media adsorption capacity, i.e., the media is tested by exposure to high concentrations of contaminated gas.

Taking the hydrogen sulfide adsorption experiment as an example, the test process is carried out in a flow system. A known volume of media was placed in an adsorption tube and exposed to a known concentration of 1 vol.% of contaminant gas in a conditioned, humidified, clean air system. The gas flow was calibrated to provide a total flow rate of 1450 ± 20 ml/min. For air flow per liter per minute, each filter bed should contain at least 300ml of media. The removal capacity is calculated as the amount of contaminants (grams) removed per volume (cubic centimeters) of air flow at 50 parts per million (ppm) of permeance.

The sorbent tube filled with media should be arranged so that the mixed gas of air and hydrogen sulfide enters from the bottom of the tube, flows through the glass wool or beads, flows through the filter media, and is then analyzed by a gas analyzer. Before starting the analysis of the sample, leaks in the gas system should be checked and excluded. Once ready in place, the flow of mixed gas was started and the time was recorded until 50ppm breakthrough was observed by the gas analyzer and the time was recorded again. It is preferred to use a gas analyzer with variable range readings, with specific or multiple gas capabilities. The data from the above analysis will yield the gas capacity of the measured medium using the following equation:

gas capacity (GM/CC) K10^-5×C×F×T/V

Wherein for H₂S, constant K1.52; c is the concentration of the feed gas in the air stream, vol.%; f is the total flow, cc/min; t is the time to reach 50ppm, min; v is the volume of the adsorption tube medium column, cc (cm)³)。

The gas analyzer used in the invention is a fixed five-in-one gas detection alarm MIC-600. The test results are shown in Table-1.

TABLE-1 test results of examples of harmful gas removing media

Serial number	Sodium permanganate content (wt%)	Adsorption capacity (10)^-3g/cm³)
			Example one	10	12.3
Example two	12	10.9
			EXAMPLE III	8	10.2
Example four	6	9.5

As is clear from Table-1, the raw material ratio in example one is the ratio that is optimal for the adsorption capacity.

Comparative example one:

adopt CN201910547521.1A harmful gas removing medium is prepared by mixing activated alumina 510g and NaHCO₃160g of adhesive consisting of 130g, 15 wt% of silicate cement and 85 wt% of calcium hydroxide, uniformly mixing, and sequentially adding into a granulation disc which continuously rotates in three batches; the granulation disk was tilted at 30 ℃ and rotated at 40rpm, while 300ml (369g) of a 27.6% strength by weight aqueous sodium permanganate solution was sprayed onto the mixture; the sodium permanganate solution is sprayed by a metering pump at the speed of 20 ml/min; stopping disc granulation and spraying when the diameter of the mixture becomes 4-6 mm, and taking out the particles; standing the particles obtained in the step at room temperature for 12h, and curing at a high temperature of 110 ℃ for 1.8h until the water content of the solid particles is 17%, thus obtaining the medium for removing harmful gases containing 10 wt% of sodium permanganate.

Example one and comparative example one, the comparative example of the granulation ratio is shown in Table-1, and the comparison of the mechanical strength (in terms of compressive strength) of the granules is shown in Table-2. Wherein the compressive strength is measured by a single-particle compressive strength tester, and the value of the compressive strength is the average value of the 20 particle compressive strength tests of the example.

TABLE 1 comparison of granulation ratios

Serial number	Raw material weight (g)	Granulation weight (g)	Granulation ratio (%)
				Example one	1169	1107	94.7
Comparative example 1	1169	942	80.6

TABLE-2 comparison of the mechanical Strength of the particles

As is clear from the results of tables-1 and-2, the granulation ratio and the mechanical strength of the granules in the extrusion granulation method of the present invention are superior to those in the disc granulation method.

For example one, the packets were tested by mercury intrusion porosimetry, and the test results are shown in Table-3.

TABLE-3 mercury intrusion test results

Sample numbering	Sample source	Porosity of the material
			1#	Example one	23.2％
2#	Example one	28.7％
			3#	Example one	17.1％

330g of the granules in the first example and the first comparative example are weighed respectively, and the granules are bonded on grids of a circular net (the aperture is 8mm, the size of the circular net is 22.5cm wide and 23.5cm long) made of PET materials by a roller gluing machine under the heating condition of 110 ℃. The bonding efficiency of the pellets to the circular net of PET material is shown in Table 4.

TABLE-4 bonding efficiency of particles with round net of PET material

Examples	Raw material weight (g)	Combined weight (g)	Binding efficiency (%)
				Example one	330.0	301.7	91.4
Comparative example 1	330.0	74.9	22.7

As is clear from Table-4, the pellets obtained by the extrusion granulation method of the present invention were bonded to the PET circular net more efficiently than the pellets obtained by the disc granulation method.

The test of the removal effect of formaldehyde was carried out by using "appendix C-test method of clean air amount of gaseous pollutants" in GB/T18801-2015 air purifier. The experimental model is an air purifier produced and sold by a third party manufacturer.

The original filter screen of the air purifier manufactured and sold by the third party manufacturer is used as a second comparative example; a filter net according to the present invention (mesh structure is made of PET and pore size is 8mm) having the same size (503 × 284 × 57mm) as the filter net of comparative example two was prepared, and a harmful gas filter medium prepared by the preparation method of comparative example one, having the same weight (815.2g) as the harmful gas filter medium in example two that effectively bonds to the mesh structure of PET, was used as example five, and the prepared harmful gas filter medium was packed in the form of a filter pack, and was used as comparative example three.

Under the conditions of the ambient temperature of (25 +/-2) DEG C, the ambient humidity of (50 +/-10)% RH and the volume of a test chamber (closed environment) of 30m³The air cleaners manufactured and sold by the third party manufacturers in example five, comparative example two and comparative example three were started up to the highest wind speed and continued for 1 hour, and then the CADR values (clean air output ratio) were shown in table-4.

TABLE-comparison of CADR values

Serial number	Form of filtration	Active ingredient	CADR value (m)³/h)
				EXAMPLE five	Filter screen	Sodium permanganate	419
Comparative example No. two	Filter screen	Activated carbon	234
				Comparative example No. three	Filter material bag	Sodium permanganate	65

As can be seen from table-4, the filter screen of the present invention has an efficient formaldehyde removal effect, and is superior to the existing commercially available filter screens having activated carbon as an active ingredient, and is greatly superior to the filter pack having permanganate as an active ingredient.

The fifth embodiment is configured as shown in fig. 1 and 2, and a filter net for removing harmful gas is composed of a net structure 3 and permanganate type inorganic particles attached to the net structure to form a permanganate type inorganic particle layer 1. The permanganate type inorganic particles are combined with the net-shaped structure in a hot melting mode, and the permanganate type inorganic particles are connected with the net-shaped structure through hot melting connection points 2. The net structure is a circular net, i.e. with circular holes 4.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A filter screen for removing harmful gases is characterized by comprising a net-shaped structure and permanganate type inorganic particles, wherein the permanganate type inorganic particles are attached to the net-shaped structure.

2. The filter screen for removing harmful gas according to claim 1, wherein the permanganate type inorganic particles are combined with the mesh structure by means of heat fusion.

3. The filter screen for removing harmful gases according to claim 1, wherein the material of the net structure is one or more of metal, inorganic material and organic material.

4. The filter screen for removing harmful gas according to claim 3, wherein the material of the net structure is organic material of PET or PP.

5. The filter screen for removing harmful gas according to claim 1, wherein the permanganate type inorganic particles include one or more of crystals of manganesite, activated carbon particles containing a permanganate solution, and activated alumina particles containing a permanganate solution.

6. The filter screen for removing harmful gas according to claim 5, wherein the permanganate type inorganic particles are activated alumina particles containing a sodium permanganate solution.

7. The filter screen for removing harmful gases according to claim 6, wherein the activated alumina particles containing the sodium permanganate solution comprise the following components in percentage by weight: 4-12 wt% of sodium permanganate, 8-20 wt% of water, 50-65 wt% of activated alumina and 12-30 wt% of binder.

8. The filter screen for removing harmful gases according to claim 7, wherein the activated alumina particles containing the sodium permanganate solution further comprise 8-20 wt% of a foaming agent, and the foaming agent is one or both of bicarbonate and aluminum powder.

9. The filter screen for removing harmful gas according to claim 7, wherein the binder is a combination of one or both of hydroxide and alkali oxide with cement; the cement is one or more of silicate cement, aluminate cement and phosphate cement, the hydroxide is calcium hydroxide, and the alkaline oxide is calcium oxide.

10. The filter screen for removing harmful gases according to claim 9, wherein the binder is a mixture of silicate cement and calcium hydroxide, and comprises the following components in percentage by weight: 12-24 wt% of silicate cement and 76-88 wt% of calcium hydroxide.

11. The filter screen for removing harmful gases according to claim 7, wherein the mesh number of the activated alumina is 80 to 325.

12. The filter screen for removing harmful gases according to claim 6, wherein the activated alumina particles containing the sodium permanganate solution are cylindrical particles, the diameter is 1-5 mm, and the ratio of the length to the diameter is 1: 20-20: 1.

13. The filter screen for removing harmful gases according to claim 7, wherein the process for preparing activated alumina particles containing sodium permanganate solution comprises the following steps:

1) thoroughly mixing the ingredients of claim 7 to obtain a mixture;

3) curing the particles prepared in the step 2) until the water content of the solid particles is 12-17%.

14. The filter screen for removing harmful gases according to claim 2, wherein the hot melt adhesive comprises one or a mixture of several of EVA hot melt adhesive, TPR hot melt adhesive, PA hot melt adhesive, PES hot melt adhesive, PE hot melt adhesive, PEA hot melt adhesive and reactive hot melt adhesive in any proportion, and the hot melt mode is to bond the permanganate type inorganic particles on the mesh of the mesh structure through the hot melt adhesive by a roller gluing machine or a spraying machine at 60-150 ℃.

15. The filter screen for removing harmful gas according to claim 5, wherein the activated alumina particles containing the sodium permanganate solution have a porosity of 10 to 40%.

16. The filter screen for removing harmful gas according to claim 15, wherein the activated alumina particles containing the sodium permanganate solution have a porosity of 15 to 30%.