DE2752985A1 - Removing malodorous basic components from gases - by contact with a support carrying an acid and or a salt - Google Patents

Abstract

The gas is contacted with a material which has been prepared by application onto a porous and heat-stable carrier of >=1 cpd. which is a proton acid and/or >=1 Lewis acid and/or an acid salt, in amt. of 1-50%, calc. on wt. of the carrier. The proton acid is phosphoric acid, borid acid, their mixt. or condensate, vanadic acid, chromic acid, an aryl-sulphonic acid esp. benzene sulphonic acid or terephthalic acid. The Lewis acid is Ni sulphate, V sulphate, Mn phosphate or their mixt. The acid salt comprises the reaction product of the above acids and a normal-shelling basic component such as NH3, methylamine, ethylamine and/or pyridine.

Description

Evil to prevent gas pollution

Odors are various devices and means of eliminating odors malodorous gases or for the release of gases depleted in malodorous substances to the atmosphere has been suggested. Such devices are based on that the gas is burned off directly or catalytically, although it is necessary is that the gas temperature is brought to a range of 300 to 10000C got to.

The warming up of large quantities of gas with only a small amount of basic gas Components with a bad smell is uneconomical because of the energy consumption. For elimination of these disadvantages, methods were investigated in which only the components are bad Smell from a large amount of gas flowing through on an adsorbent adsorbed, whereupon the adsorbed component burned off and the gas without odorous substances are released again. As gas adsorbing devices devices have been operated that use active carbon as an adsorbent. Usual more active However, carbon is responsible for adsorption and condensation Basic components with a foul odor such as ammonia and amines are not suitable, as only an extremely small amount of the components are adsorbed by activated carbon. To the Removal of basic components has also been carried out in accordance with Japanese Patent Application 38-18356 (18356/1963) proposed sulfonated carbon or ion exchange resins. These are however, they cannot be regenerated by heat, since they are reduced when heated to 100 to 3000C irreversibly decompose.

Furthermore, since exhaust gases containing nitrogen oxides NOx as well contribute to air pollution, numerous methods have been proposed to to remove NOx from gases.

In such a method, NOx is selectively reduced by ammonia. In this case, however, it is necessary to work with an excess of ammonia, since NO is usually not x with ammonia in a stoichiometric ratio of 1: 1 reacts. As a result, unreacted amounts of ammonia remain in the treated Gas. This is not only uneconomical, but possibly leads to one further air pollution due to the remaining ammonia in the exhaust gas. Usual Adsorbents and odor-eliminating substances are used to remove residual ammonia unsuitable from exhaust gas caused by such an ammonia treatment from NO has been released. This is due to the poor heat stability or adsorption efficiency of the treated gas at a higher temperature.

The invention has therefore set itself the task of providing a method for Removal of basic malodour components from such. Containing component Propose gases while avoiding the disadvantages of previous methods.

Looking for odor-preventing agents with better properties it has been found to be an extremely useful substance as an odor preventive Can use funds obtained by having a certain amount of a Acid or a salt on an inorganic carrier.

A method according to the main claim is therefore used to solve this problem proposed, with advantageous embodiments listed in the subclaims are.

In the following the invention in connection with the accompanying drawings be explained in more detail; 1 shows a schematic drawing of a method, with the basic components bad odor from one containing these substances Gas according to the invention with a continuously operating fluidized bed adsorber be removed; 2 shows a schematic representation of the method according to the invention, in which the basic components foul odor from the gas with a fixed bed adsorber are removed according to the invention.

The odor removing agent used in the method of the invention Substance is obtained by at least one compound from the group containing at least one protic acid, at least one Lewis acid and at least an acid salt on an inorganic carrier in an amount of 1 to 50% by weight, based on the carrier weight, in which case the protonic acid, Phosphoric acid, boric acid, mixtures or condensates of these two acids, vanadic acid, Molybdic acid, chromic acid, arylsulfonic acid, such as benzenesulfonic acid, or terephthalic acid, while the Lewis acid is nickel sulfate, vanadium sulfate, Manganese phosphate or mixtures of these are and the acidic salt through the reaction the mentioned protic acid and the basic component such as ammonia and / or amines is formed. The amount of those on the inorganic support Compound can be obtained from the weight difference between the odor control agents described above and charged to the carrier.

The inorganic carrier can be any substance provided that it is porous and heat-resistant. The shape of the carrier is also immaterial, however, granulated carriers whose diameter is not smaller than Is 0.2 mm and is preferably in a range of 0.2 to 2.0 mm. As a carrier are for example diatomaceous earth, silica gel, titanium oxide, zirconium oxide or silica / alumina suitable. Granulated activated carbon can also be used as a carrier. Spherical Granules of activated carbon are particularly preferred; these can be made from pitch as disclosed, for example, in Japanese Patent Application No. 49-25117 (25117/1974) and 50-18879 (18879/1975). To at least one of these Conventional methods can be used to apply compounds to the carrier.

For example, a predetermined amount of the compound in one Solvents such as water or ammonia water and the like are dissolved, whereupon a certain amount of the carrier is immersed in this solution, whereupon the solvent is distilled off from the mixture. The dried residue is on a suitable Temperature heated.

If at least one of the compounds described above is on the carrier is applied, the amount should be 1 to 50% by weight, based on the weight of the carrier, be. With lesser ones Quantities below 1% by weight make it difficult to adsorb the basic components in the gas to be purified while at Amounts above 50% by weight will separate from the carrier.

According to the invention, the gas with a content of components will be bad Odor like ammonia, alkylamines like methylamine and ethylamine, pyridine or mixtures brought this into contact with the odor-preventing substance. The contact temperature is not essential provided it is not, over 250 and preferably over 2000C. In these cases, a continuously operating fluidized bed adsorber or fixed bed adsorbers can be used. In the case of fluidized bed adsorbers, spherical particles used as a carrier because they are more abrasion resistant and a better Have fluidity.

Although the mechanism of action of odor elimination is not yet is fully clarified, it is believed that the basic components have a foul odor by a salt-forming reaction with the above-mentioned compound on the carrier adheres or is held by the wearer and has acidic character including the a Lewis acid or is an acid salt, is trapped and bound. Even in the regeneration of this odor preventing agent, it is believed that the Structure of a normal salt or analogous salt, which is obtained by combining with the basic component formed has, by heating again the adopts the original structure of an acid or an acidic salt, and the original bound components releases a foul odor. The bad smell from the components released gas can then be vented to the atmosphere. If that's to be treated Gas basic components have a foul odor and other components have a foul odor, so the gas can come into contact with a mixture of activated carbon and the one described above deodorant adsorbent are brought, with both components at the same time bad smell can be removed.

The odor preventing substance used in the invention can in the usual way by heating to a temperature above that of the contact temperature later regenerated. This regeneration temperature is not critical, provided that that it is below 1000 ° C and preferably below 500 ° C to avoid evaporation or an irreversible change in the compounds present on the carrier, the components of the odor control agent are to be avoided. When using activated carbon as a carrier is, the regeneration temperature is preferably in a range of 100 to 3000C. At temperatures below 1000C the regeneration takes too long and at temperatures Above 3000C, activated carbon can be oxidized and possibly by the oxygen in the air consumed when air is used as a regeneration gas. For regeneration are Air, nitrogen and mixtures of these are suitable. When activated carbon is used as a carrier, the regeneration is preferably carried out by means of steam. at The regeneration of used deodorants removes the components from the wearer released and can be burned down in an afterburner or with water if appropriate be washed out in a scrubber after condensation.

The odor-removing agent used according to the invention can be regenerate easily and can therefore be used several times; Gases with basic Malodor components are extremely effective in removing this.

Even basic components have a foul odor in extremely low concentrations in large amounts of gas can be effectively removed, so that the invention Process particularly for the treatment of exhaust gases from e.g. fish factories and the like suitable is. Furthermore, with the method according to the invention, ammonia can be found in exhaust gases removed after this to remove NOx by reduction with ammonia has been treated.

Example 1 (A) For the production of a carrier from carbon granules became 6 kg pitch with a softening point of 2000C and a carbon content of 94% by weight and an H / C ratio of 0.59 and with a salary of 36 wt.% In nitrobenzene-insoluble constituents used, the thermal Cracking of a Seria crude at 2000 ° C.

In addition, 1.6 kg of crude naphthalene were placed in a 20 l autoclave with a stirrer brought. After purging with nitrogen, the contents of the autoclave were stirred at Melted at 1500C and with 11 kg of a 0.22% strength by weight aqueous solution of a suspending agent from incompletely hydrolyzed polyvinyl acetate added. Then the Mix for 30 minutes at 1500C with a speed of rotation of 260 rpm.

processed into a drop-shaped dispersion and then on 300C cooled. Solidified particles of a mixture of pitch and naphthalene were obtained obtained with an average diameter of about 1 mm. The particles were 5 hours to remove the naphthalene extracted with n-hexane to form porous tar or to obtain pitch particles. These pitch particles were then placed in air at 1000C Heated to 3000C with a temperature increase of 100C per hour to make infusible To get pitch particles. These particles were activated for 10 hours with steam at 8000C, whereby activated carbon particles were obtained in a yield of 40%. The so obtained Activated carbon particles were almost spherical and had a high surface hardness and were not easily crushed. These particles were classified, whereby isolated a fraction with a particle size of 0.7 to 1.1 mm in diameter and was used as carrier Q in the following examples.

(B) As the carrier, the carbon granules Q and one were classified Fraction of coconut shell coal with a diameter of 0.7 to 1.1 mm as a carrier R used.

(C) Manufacture of the odor removing agent To the concerned chemical substance as listed in the following Table 1 to those mentioned above To apply a carbon carrier, a predetermined amount of the carrier was put into a solution with a certain amount of the chemical substance for 24 hours at room temperature left. The solution was then evaporated on a rotary evaporator. The dried residue was dried again at 90 ° C. under nitrogen for 24 hours and then heated at 2000C for 3 hours under nitrogen. Table 1 gives the carbon carriers, the chemical compound on the carrier and its amount.

For comparison purposes with conventional activated carbon and odor-preventing The means was the treatment of the gases with the coal carriers mentioned above alone or carried out with sulfonated charcoal. The sulfonated coal was made by that a bituminous coal (Yubari coal mine) with a particle size of 0.5 to 2.0 mm under air at 2200C was oxidized to infusibility and then treated with sulfuric acid at room temperature to be sulfonated Get coal. This was classified to a particle size of 0.7 to 1.1 mm and used as adsorbent S in the following examples, the ion exchange capacity of adsorbent S was 3.3 milliequivalents / g.

In the following table, experiments 1 to 14 and 16 were with the Carrier Q, the test 15 carried out with the carrier R, with test 16 as a comparative test serves, while all other attempts were according to the invention.

Table 1 Test amount in solution no. Deodorant compound% by weight medium 1 Q1 ammonium tertiary phosphate 12 water 2 Q2 dimethylamino tertiary phosphate 5 water 3 Q4 ammonium borate 10 water 4 Q5 ammonium vanadate 8 aqueous ammonia 5 Q6 ammonium chromate 14 water 6 Q7 ammonium molybdate 7 aqueous ammonia 7 Q8 ammonium salt of benzenesulfonic acid 15 water 8 Q9 ammonium terephthalate 18 water 9 Q10 phosphoric acid 4 water Try amount in solution no. Deodorant compound% by weight medium 10 Q11 phosphoric acid 8 water 11 Q12 phosphoric acid 16 water 12 Q13 phosphoric acid 32 water 13 Q14 boric acid 8 water 14 Q15 benzenesulphonic acid 13 water 15 R1 ammonium tert-phosphate 12 water 16 Q3 ammonium tertiary phosphate 0.5 water (D) For removing alkaline Components from gases became a gas mixture of 80 ppm ammonia and 10 ppm dimethylamine as basic components and 10 ppm formaldehyde and 30 ppm benzene as further components used with air. A fluidized bed adsorber and a Bunsen burner were used used to treat the condensed gas released during regeneration.

It was a continuous adsorber according to FIG. 1 made of stainless Steel used, which has a residence chamber 1 for the substance foul smell in the upper Area as an adsorption zone and a further regeneration zone 3 for the consumed Has deodorant in the lower area, with a narrow one between the two areas Passage 2 is provided. That regenerated Deodorant is through an air line 4 from the bottom of the regeneration zone 3 to the upper area of the adsorption zone 1 funded. The adsorption zone 1 is a cylinder with an inner diameter of 150 mm and contains 6 plates 10 with passage openings, which are arranged horizontally and have a vertical distance of 100 mm. The 2 mm thick panels stainless steel have openings with a diameter of 3.5 mm, so that a Passage ratio of 17% results. The bottom of the adsorption zone is funnel-shaped formed and with a cylindrical conduit 2 with an inner diameter connected by 30 mm, which is used to guide the deodorant down and a Evasion of condensed gases to prevent unpleasant smell upstairs. The regeneration zone 3 is also cylindrical and has an inner diameter of 100 mm. The upper Area is connected to the line 2, while the bottom funnel-shaped downwards merges into the air line 4. The supply line 8 is superheated steam or hot nitrogen is passed directly into the regeneration zone 3. The air duct 4 has an inner diameter of 10 mm and the transfer of the regenerated adsorbent through the pipe 4 is carried out from the line 11 by means of compressed air.

The attempts to remove odors from the synthesized test gas was in this device and with a bunsen burner 5 like follows carried out.

After charging the adsorber with the adsorbent described in (C) the gas to be treated was via the inlet pipe 6 in the lower section of the Adsorber chamber 1 with a linear speed of 90 cm / sec. initiated to fluidize the deodorant particles on the perforated plates 10.

The gas introduced was when passing through the whirled deodorant cleaned on 6 perforated plates 10 and then through an outlet pipe 7 in the upper Area of section 1 blown off. The deodorant poured from the top one first perforated plate in contact with the gas flowing upwards from plate to plate and then passed through line 2 into regeneration zone 3. The regeneration zone 3 is completely charged with the deodorant particles, which form a fluidized bed. The deodorant flows in with a controlled residence time of around 80 minutes section 3 down. Blight the deodorant with the adsorbed components Odor in adsorption zone 1 was reduced to around 2000C due to superheated steam having low nitrogen content and when flowing down became a fluidized bed regenerated in the regeneration zone 3. The regenerated deodorant was then used again up into the adsorption zone 1 via the air line 4 headed, to adsorb components of bad smell.

The malodorous condensed gas was released in section 3 and blown off via an outlet pipe 9 in the upper region of section 3 and burned with a Bunsen burner 5 and then released as an odorless gas.

The thickness of the fluidized bed on each perforated plate 10 in the adsorption section 1 was about 10 to 20 mm.

After an operating time of 60 hours with alternating adsorption and regeneration, the treated gas was at the outlet pipe 7 in the upper area of the Adsorbers 1 examined for the content of remaining components of foul odor. The results are shown in Table 2 below. Tabel 2 test no. Of ammonia dimethyl formal benzene no. Deodorant (ppm) amine (ppm) dehyde (ppm) (ppm) 1 Q1> 1 <1 2 7 2 Q2 5 1 2 6 3 Q4 <1 <1 3 8 4 Q5 3 <1 4 11 5 Q6 2 <1 3 9 6 Q7 5 <1 2 7 7 Q8 <1 <1 5 12 8 Q9 4 1 4 7 9 Q10 2 1 1 2 10 Q11 <1 <1 2 7 11 Q12 <0.5 <1 2 10 12 Q13 <0.1 <1 3 14 13 Q14 <1 <1 3 3 14 Q15 4 <1 5 12 15 R1 2 <1 6 16 1) 16 Q1 / Q * <1 <1 <1 <1 Comparison tests 1 Q 76 9 <1 <1 2 Q3 43 2 1 <1 3 8 - - - -2) 1) Significant pulverization of the deodorant occurs 2) Operation was interrupted as the adsorbent disintegrated.

* The mixture of Q1 and Q (Q1: Q = 1: 1 (volume to volume)) Annotation: The concentration of ammonia, dimethylamine, formaldehyde and benzene in the test gas before treatment was 80, 10, 10 or 30 ppm (volume).

Table 2 shows that the activated carbon carrier itself was effective, components to remove foul odor, except, however, basic components and that he almost was ineffective in removing malodorous basic components.

It has been found to act as a carrier for the chemical compounds used activated carbon has an extremely high activity in removing basic components showed a foul odor from gases. It was also found that the mixture of Activated carbon as a carrier for the chemical compounds and the carbonaceous Carrier (see Experiment 10) both the basic components and other components could effectively remove foul odor.

On the other hand, the experiments with sulfonated charcoal had to take place after 12 hours be canceled as the particles disintegrated and the adsorption activity is strong decreased due to irreversible change in regeneration at high Temperatures.

Example 2 In this experiment, additional supports made of inorganic Material used, namely carrier K: powdery diatomaceous earth became cylindrical Bodies with a diameter of 2 mm deformed, then sintered at 10000C, crushed and into granules with a particle size corresponding to 10 to 30 mesh (Tyler Standard) spotted.

Carrier S: Commercially available silica gel granules were crushed and screened to a particle size of 10 to 30 mesh (Tyler standard).

Carrier T: A gel-form titanium oxide carrier was prepared by that you first a 50% aqueous ammonia solution in a mixed solution of titanium sulfate and aluminum sulfate in a weight ratio of 90:10, the obtained Gel dried slowly and calcined at 5000C; then the granules screened to a particle size of 10 to 30 mesh (Tyler standard).

Carrier L: Commercially available silica / alumina pellets were comminuted and screened according to a particle size of 10 to 30 mesh (Tyler standard).

(B) To prepare the deodorants, a weighed amount of the The carrier is placed in a glass fluidized bed column on which an aqueous ammonia solution sprayed with a certain amount of ammonium salt while dry air at 500C was blown from the bottom of the column to fluidize the carrier while at the same time the spray solution was applied above. The carrier thus loaded with salt became two Heated for hours at 2500C, during which the acid salt was formed.

This carrier was used in the experiments to carry basic components to be held in an exhaust gas to reduce the NO content with ammonia had been treated.

x In order to coat the carrier with condensation products, was the above-mentioned carrier is heated with an acid salt for 12 hours at 3000C, during which converted the acid salt into the corresponding condensation product. The following Table 3 shows the carriers, the substances deposited thereon and the amount the same.

Table 3 Deodorant carrier compound condensed on the carrier amount K1 K Ammonium phosphate 19 K2 K condensed ammonium phosphate 14 ammonium borate 6 S1 S Ammonium nickel sulphate 11 ammonium phosphate 9 T1 T ammonium vanadine sulphate 25 L1 L ammonium manganese phosphate 11 ammonium phosphate 9 K6 K condensed phosphoric acid 14 K3 K condensed ammonium phosphate 7 K4 K condensed phosphoric acid 0.6 K K ammonium manganese phosphate 0.2 ammonium phosphate 0.4 Note: comparative experiments (C) outside the scope of the invention in this one The attempt was made to remove basic components with a foul odor from an exhaust gas that had been treated with ammonia to reduce the NOx content.

An exhaust gas containing 150 ppm of NOx was passed through an iron oxide catalyst with an ammonia supply of 225 ppm at 3500C and a throughput of 7000 h 1 to reduce of the NOx directed. The gas treated in this way with a residual content of 85 ppm ammonia was carried out as described in (B) to remove the residual ammonia the deodorants treated at a higher temperature.

The device used in FIG. 2, namely a fixed bed absorber used. A portion of the NO-depleted x gas was passed through a heat exchanger cooled to 100 to 2000C to remove residual ammonia. The isolated Ammonia was reused for further exhaust gas to remove NO x. the The device shown in Fig. 2 consists of two identical towers 1 and 1 'made of stainless Steel that is 1000 mm high and has an inner diameter of 150 mm.

Each tower contained a sieve 3 and 3 'with through openings a diameter of 0.2 mm and an opening ratio of 20%; the sieves were 300 mm from the floor. The one prepared according to (B) was in each case on the sieves Deodorant in a layer thickness of 200 mm to adsorb ammonia.

When one tower is used to treat the NO-depleted gas x was, the other tower was regenerated, with continuously every three hours has been switched. Here, part of the NO-depleted gas was brought to a temperature x cooled below 2000C and passed into the tower 1 through the inlet pipe 4, and from above into the tower. The gas flowed through the packing layer 2 at a throughput rate from 8000 h 1 to remove residual ammonia. Then the gas was over the Outlet pipe 5 discharged into the atmosphere. At the same time, nitrogen was removed from high temperature with a moisture content of 5% in the tower 1 'through the Line 6 passed and through the deodorant layer 2 'at a throughput rate of 100 h 1 to bring the deodorant to the regeneration temperature, whereby the absorbed ammonia was released. The gas that released it Approximately 6.5% by volume of ammonia was discharged via line 7 and brought in again by means of the fan 8 in the system for removing NO.

Towers 1 and 1 'were switched every three hours; it was each deodorant and each carrier K and L tested alone. 24 hours after the start the treatment, the treated gas was withdrawn from the outlet pipe 5 and its Determined ammonia content. These values are contained in Table 4 below.

Table 4 Contact regeneration residual concentration test no. Temperature temperature ammonia no. deodorant in ° C in ° C ~ in vol.% 1 K1 130 310 1 2 K1 125 270 3 3 K2 150 320 4 4 S1 120 280 4 5 T1 105 270 6 6 L1 120 270 3 7 K3 120 300 4 8 K6 130 310 1 cf. -1 K4 130 300 44 cf. -2 K5 130 300 51 * cf. -3 K 130 300 82 * Cf. -4 L 130 300 83 The comparative tests Comp. -1 to Comp. -4 were with not Deodorants according to the invention carried out.

Table 4 shows that the deodorants of the present invention are effective in ammonia can absorb at high temperatures above 1000C, during deodorants of the equalization tests -1 and -2 are practically ineffective and do not absorb sufficient ammonia.

L e r s e i t e

Claims (4)

Method for removing basic constituents from gases 1. Process for removing basic components from unpleasant odor Gases, characterized in that the gas is at a temperature not above 2500C brings into contact with a substance obtained by that one on a porous and heat-resistant inorganic support at least one Has applied compound that contains at least one protic acid and or is at least one Lewis acid and / or at least one acidic salt in a Amounts of 1 to 50% by weight, based on the weight of the carrier, are present, wherein the protic acid phosphoric acid, boric acid, a mixture of these acids or a Condensate of the same, vanadic acid, chromic acid, arylsulfonic acid or terephthalic acid and the Lewis acid is nickel sulfate, vanadium sulfate, manganese phosphate or a mixture this is and the acidic salt by reacting this acid and a basic component bad smell is formed. 2. The method according to claim 1, characterized in that the aryl sulfonic acid Benzenesulfonic acid has been used. 3. The method according to claim 1, characterized in that the basic Component is ammonia, methylamine, ethylamine and / or pyridine. 4. The method according to claim 1 to 3, characterized in that one after the gas has come into contact with the substance, it is heated to a temperature regenerated between the contact temperature and 5000C and the so regenerated substance brings again into contact with the gas containing substances of unpleasant smell.