DE2752985C2 - Process for removing basic components of unpleasant smell from gases - Google Patents

Description

The invention relates to a method for removing basic components of unpleasant odor, such as ρ ammonia or amines from gases by adding the gases to a porous support treated with an acid

i $ i brings into contact at an elevated temperature

Ig to reduce pollution are various devices by gases malodor

Il and means for eliminating odors of foul-smelling gases or for the release of substances that smell foul

|| 25 depleted gases to the atmosphere have been proposed. Such devices are based on the fact that the || Gas is burned off directly or catalytically, but it is necessary that the gas temperature to a

| f range from 300 to 1000 ⁰ C must be brought.

ilfi The warming up of large amounts of gas with only a small amount of basic components and a bad smell

|; ' is uneconomical because of the energy consumption. To eliminate these disadvantages, procedures were

; ': 30 searches where only the components of bad smell from a large amount of gas flowing through ϊ ^; 'Are adsorbed by an adsorbent material, whereupon the adsorbed component is burned off and the gas

S is released again without odor nuisance substances. As gas adsorbing devices, devices have become

H operated using the active carbon as adsorption material. However, common active carbon is for

Lv the adsorption and condensation of basic components such as ammonia and amines do not have a foul odor

i, 35 suitable because only an extremely small amount of the components of activated carbon is adsorbed.
'In Japanese patent application 38-18 356 (1963) a method for producing an ion exchange

;; · Schers made of carbonaceous material. In this process, the charcoal-like material is first made with

I '. Hydrochloric acid and then treated with sulfuric acid. Through this treatment, the carbonaceous material is said to be

■ at the same time be made capable of adsorbing gases, which was previously the case with conventional ion exchangers 40 basis of carbon was not possible. The adsorptive capacity achieved in this way is said to be that of activated

^; ;!, -: correspond to carbon. In one example, the ability to adsorb chlorine gas from aqueous

: "Solution detected. In an analogous way, the ion exchanger should also react to sulfur dioxide and ammonia

and hydrogen sulfide act. An indication that this ion exchanger can be used to remove basic

; '■■■ see components containing unpleasant smells such as ammonia or amines from gases would be suitable

';; 45 this patent application does not. The ion exchangers cannot be regenerated by heating either, since they are irreversibly decompose at 100-300 ° C.

In CH-PS 1 85 411 a process for the production of an adsorbent is described in which one : Aluminum silicate of the montmorillonite type, mixed with water, forms into bodies, dries and then

: subjected to prolonged heating to a temperature between 400 and 800 ° C.

■ ' ^! DE-PS 4 86 075 describes a process for improving the adsorption capacity of active charcoal constituents, in which a liquid acid is imparted to the active charcoal. As suitable liquid acids; , · Sulfuric acids, phosphoric acid, nitric acid, acetic acid, citric acid and tartaric acid are given.

In US-PS 17 77 459 is the improvement of the adsorption capacity of porous substances such as tree-I cotton wool or blotting paper as well as powdered material such as kieselguhr. The improvement

; 55 is obtained by impregnating with a high molecular weight sulfonic acid.

There is no suggestion of adsorbability for

;. basic components with an unpleasant smell such as ammonia or amines from gases.

). Furthermore, since exhaust gases containing nitrogen oxides NO ₁ also contribute to air pollution

; .. numerous methods have been proposed to remove NO from gases. In such a procedure

60 NO _x is selectively reduced by ammonia. In this case, however, it is necessary to work with an excess of ammonia, since NO ₁ usually does not work with ammonia in a stoichiometric ratio of 1: 1

reacted. As a result, unreacted amounts of ammonia remain in the treated gas. This is not only uneconomical, but possibly leads to further air pollution due to the lagging behind Ammonia in the exhaust gas. Usual adsorbents and odor-removing substances are to be removed It is unsuitable to use residual ammonia from exhaust gas, which is produced by such an ammonia treatment of 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 removing basic components

To propose foul odor from gases containing such components, and here the disadvantages of earlier Procedure to avoid.

In the search for odor control agents with better properties, it has been found that one extremely suitable substance can be used as an odor preventing agent obtained by absorbs a certain amount of a salt on an inorganic carrier.

To solve this problem, a method according to the main claim is proposed, with advantageous Embodiments are listed in the subclaims.

In the following, the invention will be explained in more detail in connection with the accompanying drawings; it shows

1 is a schematic drawing of a method by which basic components exude odor a gas containing these substances according to the invention with a continuously operating fluidized bed adsorber be removed,

F i g. 2 a schematic representation of the method according to the invention, in which the basic components foul odor can be removed from the gas with a fixed bed adsorber according to the invention.

In the method according to the invention, nickel sulfate and vanadium sulfate are used as odor-removing substances and / or manganese sulfate or a reaction of ammonia and / or amines with phosphoric acid, Boric acid, vanadium acid, chromic acid, arylsulfonic acids and / or terephthalic acid used Of these substances, 1 to 50% by weight, based on the weight of the carrier, are based on the inorganic Carrier or applied to active carbon

The amount of the compounds located on the inorganic support can be determined from the difference in weight between the above-described odor control agents and the carrier.

The inorganic carrier can be any substance provided it is porous and heat-resistant is. The shape of the carrier is also immaterial, but granulated carriers are preferred, their Diameter is not less than 0.2 mm, and is preferably in a range of 0.2 to 2.0 mm. As a carrier For example, diatomaceous earth, silica gel, titanium oxide, zirconium oxide or silica / alumina are suitable. Further Granulated activated carbon can be used as a carrier. Spherical granules are made of activated carbon particularly preferred; these can be made from pitch, as is the case, for example, in the Japanese Patent Application Nos. 49-25 117 (25 117/1974) and 50-18 879 (18 879/1975). To at least Conventional methods can be used to apply either of these compounds to the substrate. For example can be a predetermined amount of the compound in a solvent such as water or ammonia water and the like are dissolved, after which 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 heated suitable temperature.

If at least one of the compounds described above is applied to the carrier, its Amounts are 1 to 50% by weight based on the weight of the carrier. For smaller amounts under 1 Wt .-%, it is difficult to adsorb the basic components in the gas to be purified, while at Amounts above 50% by weight will separate the compound from the carrier.

According to the invention, the gas is made with a content of bad odor components such as ammonia, alkylamines such as methylamine and ethylamine, pyridine or mixtures of these in contact with the odor-preventing Brought substance. The contact temperature is not critical provided it does not exceed 250 and is preferably above 200 ° C. 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 are preferably used as Carriers are used because they are more abrasion resistant and have better fluidity.

Although the mechanism of action of odor elimination is still fully understood, it is assumed that that the basic components have a foul odor due to a salt-forming reaction with the above-mentioned Compound adhered to or held by the wearer and having an acidic character including the a Lewis acid or is an acid salt, is trapped and bound. This also applies to regeneration Odor preventing agent is believed to have the structure of a normal salt or analog Salt, which has formed through connection with the basic component, can be restored by heating adopts the original structure of an acid or an acidic salt, and the originally bound components releases a foul odor. The gas freed from the components of bad odor can then be fed into the Atmosphere to be blown off. If the gas to be treated has basic components and offensive smell If other components contain a foul odor, the gas can come into contact with a mixture of activated carbon and the deodorant adsorbent described above are brought, both at the same time Components with a bad smell are removed.

The odor-preventing substance used in the invention can later be regenerated in a conventional manner by heating to a temperature above the contact temperature. This regeneration temperature is not critical, provided that it is less than 1000 ⁰ C and preferably below 500 ° C, to an evaporation or an irreversible change existing on the carrier compounds DJE components of the odor control agent to be avoided. When activated carbon is used as the carrier, the regeneration temperature is preferably in a range of 100 to 300 ° C. At temperatures below 100 ° C, the regeneration takes too long and at temperatures above 300 ° C, activated carbon can be oxidized and possibly consumed by the oxygen in the air if air is used as the regeneration gas. Air, nitrogen and mixtures of these are suitable for regeneration. If activated carbon is used as a carrier, regeneration is preferably carried out by means of steam. When used deodorants are regenerated, the components are released from the carrier and can be burned off in an afterburner or washed out with water in a washer, if necessary after condensation.

The odor-removing agent used according to the invention can be easily regenerated and can therefore

ge can be used multiple times; Gases with basic components of foul odor can be extremely effective eliminate in this way. Even basic components have an extremely low concentration in bad smell large amounts of gas can be effectively removed, so that the method according to the invention is particularly suitable for Treatment of exhaust gases z. B. from fish factories and the like is suitable. Furthermore, with the invention Process ammonia in exhaust gases can be removed after this to remove NO, through Reduction has been treated with ammonia.

example 1

(A) For the preparation of a support of carbon granules 6 kg pitch were having a softening point of 200 ⁰ C and a carbon content of 94 wt ° / o and a H / C ratio of 0.59 and with a content of 36 wt. -% used in nitrobenzene insoluble constituents, which had been obtained by thermal cracking of a Seria crude oil at 2000 ⁰ C. In addition, 1.6 kg of crude naphthalene were placed in a 20 l autoclave with a stirrer. After purging with nitrogen, the autoclave was melted with stirring at 150 ⁰ C and O, 22gew.- ° / o aqueous solution of 11 kg of a suspending agent of incompletely hydroüsiertem polyvinyl acetate added then the mixture was 30 minutes at 150 ⁰ C with a rotation speed of 260 rpm, processed into a drop-shaped dispersion and then cooled ^{to 30 ° C.} Solidified particles of a mixture of pitch and naphthalene with an average diameter of about 1 mm were obtained. The particles were extracted with η-hexane for 5 hours to remove naphthalene to obtain porous tar particles. This pitch particles were then heated in air at 100 ⁰ C to 300 ⁰ C with a temperature increase of 10 ⁰ C per hour, to obtain infusible pitch particles. These particles were activated for 10 hours with steam at 800 ^° C., activated carbon particles being obtained in a yield of 40%. The activated carbon particles thus obtained were almost spherical in shape, had a large surface hardness and were not easily crushed. These particles were classified, a fraction having a particle size of 0.7 to 1.1 mm in diameter being isolated and used as carrier Q in the following examples.

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

(C) Manufacture of odor removing agents

In order to apply the chemical substance concerned, as shown in the following Table 1, to the above-mentioned carbon carriers, a predetermined amount of the carrier was left in a solution containing a certain amount of the chemical substance at room temperature for 24 hours. The solution was then evaporated on a rotary evaporator. The dried residue was again dried for 24 hours under nitrogen at 90 ° C and then heated for 3 hours under nitrogen at 200 ⁰ C. Table 1 gives the carbon support, the chemical compound on the support and their amount.

For purposes of comparison with conventional activated charcoal and odor-preventing agents, the treatment of the gases was carried out with the above-mentioned charcoal carriers alone or with sulfonated charcoal. The sulfonated carbon was prepared by a bituminous coal (coal mine Yubari) having a particle size of 0.5 to 2.0 mm in air at 22O ⁰ C until infusibility was oxidized and was then treated at room temperature with sulfuric acid, 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 being 3.3 milliequivalents / g.

\ n the following table were the attempts! to 8 and the comparative test with the carrier O. the test 9 with the carrier R carried out

Table 1

Attempt no. '

deodorant

Compound amount in% by weight

solvent

1 Qi 2 02 3 Q4 4th Q5 5 Q6 6th Q7 7th Q8 Ot) Q9 9 R \ Comparison Q3 attempt

Ammonium tert-phosphate

Dimethylamino-tert-phosphate

Ammonium borate

Ammonium vanadate

Ammonium chromate

Ammonium molybdate

Ammonium of benzenesulfonic acid

Ammonium terephthalate

Ammonium tert-phosphate

Ammonium tert-phosphate

12th water 5 water 10 water 8th aqueous ammonia 14th water 7th aqueous ammonia 15th water 18th water 12th water

water

(D) To remove basic components from gases, a gas mixture of 80 ppm ammonia and 10 ppm dimethylamine as basic components and 10 ppm formaldehyde and 30 ppm benzene as additional components Components used with air. A fluidized bed adsorber was used and a Bunsen burner was used

Treatment of the condensed gas given off during regeneration is used.

A continuous adsorber according to FIG. 1 used stainless steel of a residence chamber 1 for the substance has a foul odor in the upper area as an adsorption zone and a further regeneration zone 3 for the used deodorant in the lower area, with a between the two areas narrow passage 2 is provided. The regenerated deodorant is through an air duct 4 from the bottom of the Regeneration zone 3 promoted to the upper area of adsorption zone 1. The adsorption zone 1 is a Cylinder with an inner diameter of 150 mm and contains 6 plates 10 with through 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 there is a passage ratio of 17% results. The bottom of the adsorption zone is funnel-shaped and has a cylindrical shape Line 2 connected with an inner diameter of 30 mm, which serves to the deodorant down and to prevent condensed gases with a bad smell from escaping upwards. The regeneration zone 3 is also cylindrical and has an inner diameter of 100 mm. The top area is with the pipe 2 connected, while the bottom merges into the air duct 4 in a funnel-shaped manner. Through the supply line 8, superheated steam or hot nitrogen is fed 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 Tube 4 is passed through line 11 by means of compressed air.

The attempts to remove odors from the synthesized test gas were carried out in this device and with a Bunsen burner 5 carried out as follows.

After the adsorbent was charged with the adsorbent described in (C), that to be treated became Gas via the inlet pipe 6 into the lower section of the adsorber chamber 1 at a linear speed of 90 cm / sec. initiated to fluidize the deodorant particles on the perforated plates 10.

The gas introduced was cleaned on 6 perforated plates 10 as it passed through the whirled up deodorant and then blown off via an outlet pipe 7 in the upper region of section 1. The deodorant first flowed from the uppermost perforated plate into contact with the gas flowing upwards from plate to plate and then passed via line 2 into regeneration zone 3. Regeneration zone 3 is completely charged with the deodorant particles, which form a fluidized bed. The deodorant flows downward in section 3 with a controlled residence time of about 80 minutes. The deodorant with the bad odor adsorbed components in adsorption zone 1 was ^{heated to about 200 °} C. by superheated steam with a low nitrogen content and was regenerated as a fluidized bed in regeneration zone 3 as it flowed downwards. The regenerated deodorant was then passed back up into the adsorption zone 1 via the air line 4 in order to adsorb components of bad smell. The condensed gas with a foul odor was released in section 3 and blown off via an outlet pipe 9 in the upper area 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 at the outlet pipe 7 in the upper area 1 of the adsorber for the content of remaining Malodor components examined. The results are shown in Table 2 below.

Table 2

Test number of the deodorant ammonia dimethylamine formaldehyde benzene
(ppm) (PPm) (ppm) (ppm)

1 Ql <1 <1 2 7

2 Q2 5

3 Q4 <

4 Q5 3

5 Q6 2

6 Q 7 5 <1 2 7

7 Q8 <

8 (? 9 4

9 /? 1 2

10 QUQ *) <

Comparative experiments

1 Q 76

2 Q 3 43

¹ ) Significant pulverization of the deodorant occurs.

² ) Operation was stopped because the adsorbent disintegrated.

*) The mixture of Q 1 and Q (Q \: Q = \: \ (volume to volume)).
Annotation:

The concentration of ammonia, dimethylamine, formaldehyde and benzene in the test gas was before the treatment 80 or 10 or 10 or 30 ppm (volume).

Table 2 shows that the activated carbon carrier itself was effective in removing malodor components, except, however, basic components and that it was almost ineffective, basic components foul

<1 2 7th 1 2 6th <1 3 8th <1 4th 11th <1 3 9 <1 2 7th <1 5 12th 1 4th 7th <1 6th 16 ·) <1 <1 <1 9 <1 <1 2 1 <1

Remove odor.

It has been found that the activated carbon used as a carrier for the chemical compounds is extremely one showed high activity in removing basic components of malodor from gases. It was further found that the mixture of activated carbon as a carrier for the chemical compounds and the carbonaceous Carriers (see Experiment 10) foul both the basic components and other components Could effectively remove odor.

On the other hand, the experiments with sulfonated charcoal had to be stopped after 12 hours because the Particles disintegrated and the adsorption capacity fell sharply due to an irreversible change in the Regeneration at high temperatures

Example 2
In this experiment, other supports made of inorganic material were used, viz

Carrier K:

powdery diatomaceous earth was shaped into cylindrical bodies with a diameter of 2 mm, then sintered at 1000 ° C, crushed and made into granules with a particle size corresponding to 10

up to 30 meshes (Tyler standard) sighted.
Carrier 5:

Commercially available silica gel granules were comminuted to a particle size of 10 to 30 mesh

(Tyler Standard) spotted.
Beam T:

A gel-like titanium oxide carrier was prepared by first adding a 50% strength ammonia solution in a mixed solution of titanium sulfate and aluminum sulfate in a weight ratio of 90:10, the gel obtained was slowly dried and calcined at 500 ° C .; then the granulate was on a

Particle size from 10 to 30 mesh (Tyler standard) sighted.
Carrier L:

Commercially available silica / alumina pellets were comminuted and made according to a particle size from 10 to 30 meshes (Tyler standard) sighted.

(B) For the preparation of deodorants, a weighed amount of carrier into a glass fluidized bed column was added to the sprayed an aqueous ammonia solution with a certain amount of ammonium salt, was injected to fluidize the carrier while dry air at 5O ⁰ C from the bottom of the column, while at the same time the spray solution was applied above. The loaded with salt as carrier was heated for two hours at 25O ⁰ C, wherein the acid salt formed. This carrier was used in the tests to hold basic components in an exhaust gas that had been treated with ammonia to reduce the ΝΟ, content.

In order to coat the carrier with condensation products, the mentioned carrier was ^{heated with an acid salt for 12 hours at 300 °} C., the acid salt being converted into the corresponding condensation product. The following Table 3 shows the carriers, the substances deposited thereon and the amount thereof.

Table 3 carrier Connection on the carrier lot deodorant K condensed ammonium phosphate 19th K condensed ammonium phosphate 14th K ₂ Ammonium borate 6th S. Ammonium nickel sulfate 11th 5, Ammonium phosphate 9 T Ammonium vanadium sulfate 25th T ₁ L. Ammonium manganese phosphate 11th Li Ammonium phosphate 9 K condensed ammonium phosphate 7th K ₃ K Ammonium manganese phosphate 0.2 *) Ks Ammonium phosphate 0.4

Annotation:
*) Comparative tests outside the scope of the invention.

(C) In this experiment, basic malodour components were removed from an exhaust gas that was used for Reduction of the NCV content had been treated with ammonia.

An exhaust gas with a content of 150 ppm NO * was passed through an iron oxide catalyst with an ammonia supply of 225 ppm at 350 ^° C. and a throughput of 7000 h ~ 'to reduce the NO. The gas treated in this way with a residual ammonia content of 85 ppm was treated as described in (B) to remove the residual ammonia by means of the deodorants at a higher temperature

Here, the in F i g. 2 device used, namely a fixed bed absorber is used. Part of the

The NO depleted gas was ^{cooled to 100 to 200 °} C. by a heat exchanger in order to remove residual ammonia. The isolated ammonia was used again with further exhaust gas to remove NO. The in F i g. The device shown in FIG. 2 consists of two identical towers 1 and Γ made of stainless steel, which are 1000 mm high and have an inner diameter of 150 mm. Each tower contained a screen 3 and 3 'with passage openings with a diameter of 0.2 mm and an aperture ratio of 20%; the sieves were 300 mm from the floor. The deodorant produced according to (B) was located on each of the sieves in a layer thickness of 200 mm in order to adsorb ammonia. If one tower was used to treat the NO depleted gas, the other tower was regenerated, with continuous switching every three hours. In this case, part of the gas depleted in NO, was ^{cooled to a temperature below 200 °} C. and passed into the tower 1 through the inlet pipe 4, from above into the tower. The gas flowed through the packing layer 2 at a throughput rate of 8000 h- 'in order to remove residual ammonia. The gas was then discharged into the atmosphere via the outlet pipe 5. At the same time, nitrogen of high temperature with a moisture content of 5% was passed into the tower 1 'through the pipe 6 and passed through the deodorant layer 2' at a rate of 100 h- ¹ to bring the deodorant to the regeneration temperature, whereby it was absorbed Ammonia was released. The gas. which contained the released ammonia in an amount of about 6.5% by volume, was drained via line 7 and returned to the system for removing HO _x by means of blower 8.

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

Table 4

Attempt no.

No deodorant

Contact temperature
in-C

Regeneration temperature
in "C

Residual concentration

ammonia

in% by volume

1 Kx 130 310 1 2 K ₁ 125 270 3 3 K ₂ 150 320 4th 4th S ₁ 120 280 4th 5 7 ", 105 270 6th 6th L _x 120 270 3 7th AT ₃ 120 300 4th ·) VgL-I K ₅ 130 300 51 •) VgL-2 K 130 300 82 ^# ) See -3 L. 130 300 83

25th 30th 35

*) The comparative experiments Comp. -1 to Comp. -3 were made with deodorants not according to the invention carried out.

Table 4 shows that the deodorants according to the invention can effectively ^{absorb ammonia at high temperatures at 100 °} C., while the deodorant of Comparative Experiment -1 is practically ineffective and does not absorb ammonia sufficiently.

For this purpose 2 sheets of drawings

40

50

55

Claims (3)

Patent claims: 1. Process for removing basic components of unpleasant odor, such as ammonia or Amines from gases by treating the gases with an acid-treated porous support at increased 5 brings temperature into contact, characterized in that the gas is at a temperature of not more than 250 ° C in contact with a porous support obtained by that on the porous and heat-resistant inorganic support or on active carbon 1 to 50% by weight, based on the weight of the carrier, nickel sulfate, vanadium sulfate and / or manganese phosphate or a by reacting ammonia and / or amines with phosphoric acid, boric acid, vanadium acid, chromium 10 acid, arylsulfonic acids and / or terephthalic acid has been applied 2. The method according to claim 1, characterized in that a methylamine, ethylamine or amine Pyridine has been used 3. The method according to claim 1 or 2, characterized in that the exhausted porous carrier is ^{regenerated by heating to a temperature between the contact temperature and 500 0} C and the such 15 brings regenerated carrier back into contact with the gas to be treated