DE2410411A1 - PROCEDURES FOR THE DISPOSAL OF AMMONIA, IN PARTICULAR COOKING AMMONIA - Google Patents

Description

Essen, March 4, 1974 N 461O / 7C Dr Ha / En

Heinrich Koppers company with "limited liability, 43 Essen, Moltkestrasse 29

Process for the elimination of ammonia, in particular ■ of coking ammonia

The invention relates to a method for removing ammonia, in particular coking ammonia, by incineration the ammonia vapors expelled with water vapor in the presence of air.

It is known that the ammonia contained in it must be removed from the coke oven gas, since the same works together with the other accompanying substances in the coke oven gas, corrosion in the pipelines and equipment Establishments evokes.

Various methods have therefore already been used to remove the ammonia from the coke oven gas. So you can for example lead the coke oven gas through a saturator in which the ammonia of the gas means Sulfuric acid converted to ammonium sulfate and this is then crystallized out of the solution.

Another method is the coke oven gas in one

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Absorption tower (Wascner) with a suitable washing liquid washed, which dissolves the ammonia and removes it from the gas. As a suitable washing liquid in this Process, in particular water, is used, the ammonia being extracted from the ammonia-laden water by simple distillation can be driven off with steam. The resulting ammonia vapors can either form ammonium sulfate be converted, but they can also be worked up to form strong ammonia water or compressed ammonia will.

For the products just mentioned, however, the sales opportunities have increased has deteriorated very much in recent years, and today it is hardly possible to make these products one To deduct the price that covers the production costs. That is why one has more and more of this in recent times For several decades known method made use of burning the ammonia vapors in the presence of air. In addition to nitrogen and water, nitrogen oxides are also formed, which together with the other components as Smoke gases get into the atmosphere. The ever stricter environmental protection regulations make it necessary, however, reduce the nitrogen oxide content of the flue gases resulting from ammonia combustion as drastically as possible.

The invention was therefore based on the object of providing a method

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for the elimination of ammonia, especially coking ammonia, to develop by combustion in the presence of air, "at that of the ammonia incineration Flue gases contain as little nitrogen oxide as possible.

Eieses object is achieved in a method of the initially described type according to the invention characterized in that the Ammoniakbrüden partially combusted first with oxygen deficiency at a temperature of 95O ⁰ C to 1150 ⁰ G and then completely combusted with excess oxygen at a temperature of 95O ° C to 105O ⁰ C. The optimal combustion temperature in the second stage is set by adding recirculated flue gas accordingly and the sensible heat of the flue gases produced during combustion is used to generate steam.

Further details of the method according to the invention are given below with reference to what is shown in the figure Flow diagrams are explained. Has flow diagram shows only the parts of the plant necessary to explain the process, while ancillary facilities and the associated ones Measurement and control systems are not shown.

The ammonia vapors intended for combustion are fed to burner 2 through line 1. To the for the first stage of combustion envisaged in this case

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Comply temperature of 95O ° C to 115o C and ⁰ achieve a stable flame formation to be may be a heating medium through the line 3 in addition, for example, be introduced into the burner 2 coke oven gas. However, another heating medium, such as natural gas, oil or the like, can also be used. The necessary combustion air is supplied via line 4 and fan 5. Lines 6, 7 and 8 branch off from line 4.

In the first combustion stage, an oxygen deficit is used. That is, by the lines 6 and 7 is fed as much air into the burner 2 that the partial combustion of the Ammoniakbrüdens and the heating medium in the Stage One is carried out at an oxygen amount from 90 to 99 _f 9% of the ammonia for the complete combustion to Nitrogen and water required theoretical value.

After the flames in the front part of the combustion chamber 9 have burned out, further air is introduced into the middle to rear part of the combustion chamber 9 through the line 8. At the same time, recirculated flue gas is added through lines 15 and 16. This is dimensioned so that in the second combustion stage, which occurs at a temperature between 95O ⁰ C and 1050 ⁰ C

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should run, the optimum combustion temperature is maintained. Since the second combustion stage is to be carried out with excess acid, the addition of air through line 8 and of recirculated flue gas through lines 15 and 16 must also be adjusted so that an amount of oxygen is fed to the middle and rear part of the combustion chamber 9, the / is between 100.1 to 110 ° o, required for the complete combustion of ammonia to nitrogen and water · value.

The waste heat boiler 10 is connected directly to the combustion chamber 9, in which the "accumulating during the combustion Smoke gases get in. These are cooled in the waste heat boiler 10, their sensible heat being used to generate steam will. The required feed water supply to the waste heat boiler 10 takes place through the line 17, while the generated steam is withdrawn through line 18. To maintain a constant boiler water quality the waste heat boiler 10 is drained and the resulting Waste water is withdrawn through line 19.

The cooled flue gases leave the waste heat boiler 10 through the line 12, in which they reach the chimney 20. The smoke gases escape into the atmosphere through this. In front of the chimney 20, however, branches off from the line 12 Line 13 through which some of the flue gases mediate

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the fans 14 and via the lines 15 and 16 again is returned to the combustion chamber 9. But this is where it is has already been discussed above.

The following process example, the ammonia incineration plant a coke oven gas treatment with an output of 135,000 ITur / h coke oven gas should the practical utility of the method according to the invention demonstrate. The following data is determined for the individual parts of the system:

a) Ammonia vapor through line 1ϊ

2,677 lTm ³ / h, t = 7O ⁰ C 53.8 I.
» 25 ⁰ C Vol. containing: IiH- approx. 0.8 1.5 Il H ₂ S « 18.4 2.7 It CO ₂ » 0.2 η HClT ^π 26.8 Il H ₂ O « b) Heating medium through line 3: 400 ITm ³ coke oven gas / h; t = Vol. containing: CO ₂ approx. Il CnIIm "

509837/0461

- 7th - approx. 0.5 ToI 241041
HK 1 ti 6.3 Il March 4th 1
Έ 461O / 7C 974 ° 2 Il 57.5 Il CO Il 25.5 Il H ₂ CH,

6.0

ο) air through line 6: 1801 Nm ³ / h; t = 25 ° C

d) air through line 7: 4336 Nm ³ / h; t = 25 ⁰ C

e) Combustion temperature in the first combustion stage: 1050 ^° C.

f) amount of oxygen in the first combustion stage;

95 i> of the theoretical value

g) air through line 8; 1700 ifm ³ / hi t = 25 ⁰ C

h) flue gas through line 15; 9944 km ³ / h; t = 35O ⁰ C

i) flue gas through line 16; 736 at ³ / h; t = 35O ⁰ C

.i) combustion temperature in the second combustion ■ stage; 1020 ⁰ C

k) Oxygen lance in the second combustion 3 stage; 110 io of the theoretical value

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l) flue gas temperature:

before the waste heat boiler 10: 10? O ⁰ G after, the waste heat boiler 10: 35O ⁰ C

m) Total amount of flue gas: 21 828 Nm ³ / h

n) flue gas to the chimney 20: 11 148 Nm ⁵ / h; t = 350 ⁰ C containing: CO

CO ₂ approx. 6th , 0 Vol. % ° 2 η 1 , 3 ti so ₂ tr 0 , 2 η IT ₂ η 62 , 3 11 H ₂ O π 30th , 2 η ITO η 120 ppm

ο) saturated steam through line 18: 9.3 t / h; 16 atü

The above data show that the process according to the invention enables the combustion of the the coke oven gas treatment accumulating ammonia to be carried out so that in the resulting and in the atmosphere the exhausted flue gases contain very little nitrogen oxides. The inventive method requires only slightly higher investment costs than this because of the flue gas recirculation

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"in other prior art processes the pail is. Compared to these known methods, which either with a large excess of air or with increased Working combustion temperatures, the method according to the invention is characterized in that the IiO emission is reduced to about a third.

Of course, the applicability of the method according to the invention is not only applicable to the above Process example applied, practically H ^ S-free Limited ammonia vapors. Rather, ammonia vapors can also be used which cause considerable have higher H ^ S content and the possibly can also come from a source other than coke oven gas.

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Claims (1)

HK March 4, 1974 IT 4610 / 7O Claims Process only removal of ammonia, in particular of Kokereiairmioniak by incineration of the Amoniakbrüden expelled with water vapor, in the presence of air, characterized in that the Aimnoniakbrüclen initially partially burned with satire deficit at a temperature of 950 C to 1150 C and then with excess oxygen at a temperature of wherein the optimum combustion temperature is adjusted in the second Siiufe by appropriate addition of recirculated flue gas and the sensible heat of the "is used in the combustion resulting flue gases to generate steam are completely combusted to 1050 ⁰ C,. ?.) Method according to claim 1, characterized in that that in the first combustion stage an additional suitable heating mode, v / ie for example coke oven gas, with being burned. 3.) Process according to claims 1 and 2, characterized in that the amount of oxygen in the first combustion stage is 90 to 99, ^α f- and in the second combustion stage 100.1 to 110 # of the theoretical value required for the combustion. 5 0 9 8 3 7/0451 241041Γ HK March 4, 1974 N 4610 / 7C Λ,) Method according to claims 1 "to 3, characterized in that the returned flue gas is divided into several partial flows and introduced into the combustion chamber at different points. 5 09837/0451 Empty