DE1769640C - Use of a molded coke made from powdery, non-baking, fossil or recent fuel materials as an adsorbent for sulfur oxides from Ab - Google Patents

Description

ι ²

In the exhaust gases of industrial production facilities, a molded coke is used that is produced by mixing

often contain harmful sulfur oxides. One is of powdery, non-baking, fossil or race

therefore endeavors to keep the air clean, these sulfur fuels with a grain size IUO / _q under I ₁ HiW ₁

to remove fel oxides from the exhaust gases. preferably less than 0.1 mm, with about Ii pis is Ue-

It is known that harmful sulfur oxides, in particular 5 percent by weight bitumen, tar or pitch as binders,

special SO ₂ , on crushed charcoal or forms of green mass and degassing at J empera-

To bind charcoal and they have been produced through thermal doors between about 500 and 900 C.

Treatment at 300 to 400 ⁰ C is highly enriched. As non-baking fuels are for example

Win form as SO _8. It is also known to produce charcoal, peat coke, lignite and oxy coal.

charcoal, peat coke or brown io are suitable as adsorbents.

kol lenkol s at temperatures between 100 and 200 ⁰ C. It has now been found that such em coke to use and especially to regenerate these adsorbents at temperatures awarded for a Adsorpren between 300 and 600 ^0C. In the regeneration process at temperatures between 100 and 200 C rer time, the desulphurisation of SO ₂ and SO ₃ can be subjected to a scrubbing with water, the use of lumpy, porous semi-cokes prior to x ₅ if a molded coke has been used as adsorption coke, which in particular comes from recent applies, which after degassing fuels such as peat or lignite produced at temperatures between about 500 and 90O ⁰ C with steam be: It has been recognized that in the presence of temperatures between about 800 and 1000 ⁰ C active water vapor and oxygen that was initially adsorbed has been fourth. The duration of this activation should be _{between 2 and 12 hours for SO 2} to be oxidized to sulfuric acid. Surprisingly, with the thermal regeneration due to this activation, the high mechanical oxidizing effect of the sulfuric acid leads to a niche strength and abrasion resistance of the molded coke _{. Partial gasification of the coke with CO 2} formation. not lost.

In this way, the water vapor can actively ation of Formkokses, the burn-tion of 50 ° / _0, based on the areas of use as to a high carbon burnup and weight so that the cokes, and more occur after repeated regeneration. Since with the mo- a large pore volume, depending on the requirements, adsorption systems can be carried out to remove genes from the adsorbent, sulfur oxides can be carried out from exhaust gases, in particular furnace, surprisingly does not necessarily have an exhaust gas effect, the lump coke usually in the form of a very high one Burn-off is cheapest. Wanderachicht in the cycle through the adsorption 30 The properties of the adsorption coke required for the described desulfurization process and then through the desorption system, it is subject to a high mechanical load, namely only with regard to the desulfurization stress. That is why the resulting abrasion, disactivity and water absorption capacity are extremely large. Abrasion is most favorable when the steam activation is not continuously burned off during the process and is carried out particularly intensively. As a standard for significantly increased, since the substance volume during this the intensity of the water vapor activation can be used, the partial gasification naturally the friability of the carbon burn-off of the molded coke. Coke greatly enlarged. This abrasion is, however, according to the invention, the water vapor activation is undesirable, since it severely impairs the gas permeability of the moving layer up to a moving layer in order to achieve particularly good results. He has to continuously burn off the coke between about 10 and 30 people by sieving the coke away by weight. The result of the tests is shown in Table 1, which relates to

It is also known that, with sulfuric acid, steam activation of shaped cokes from loaded adsorption cokes is obtained by washing with oxidized hard coal. When using other water or aqueous ammonia solution to regenerate starting materials, in principle similar results are obtained, with direct results without loss of adsorption material. As Table 1 shows, sulfuric acid or ammonium sulfate solution is obtained below. 10 ° _{/ 0} burn low water absorption, equal · However, remains after washing out the true with if this but also for the Entschwefelungsaktivi-60 to 80 ° / ₀ sulfuric acid laden adsorption 'did. Above 30 percent by weight burn-off, part of the wash in the pore volume of coke rises, so, as expected, the water absorption capacity of white water decreases. If one is washed out in this way, whereas, surprisingly, the desulphurized adsorption coke decreases again very sharply to an intermediate activity at temperatures. The adsorption system operated at 100 and 200 ⁰ C sulfur limit 90 ° / "is a measure for the return, so the remaining water- sulphurizing activity of an adsorption coke and quantity must first be removed by Ttoeknen de» coke 55 indicates the time after which the initially 100 ° /, or at the beginning of the adsorption process from the / · amount of desulfurization of a summed desulfurizing, both exhaust gases are removed as steam adsorption coke under specified conditions. For the success of one on one, the temperature has just dropped to 90 ^e / · . In the present temperature between 100 and 200 C, in the case of a steam-activated sorption of the sulfur oxides, regeneration of the sulfur oxides with 100 cm ¹ volume of water was washed out, so it is essential that the (50 cm high) at 120 C Less than $ seconds Gasver * Adsorbent during adsorption indeed very dwell time of an exhaust gas, consisting of 0.3 volume · well and very long the sulfur hide binds and ptocent SO "3.0 volume percent O", 6.0 volume * so very much Sulfuric acid can absorb, orozent H ₄ O vapor and 90.7 percent by volume N _t over a mul of the wipe only little water flows back through. The grain size of the molded coke was retained. ! wipe I and 2 mm. The water absorption capacity was determined using the method de »main patent I 28 J» 07 with drained, moist adsorption coke as an adsorbent for Svliw «rf <l»> \ idi au »Ah *.

Table 1

Serial
No. Burn-off
Weight Water absorption
assets
ml / 100 cm ¹ Desulfurization
limit 9O ^p / o percent A-coke hours 1 3.0 10.0 about 0.8 2 8.0 11.3 6.0 3 10.0 12.0 7.5 4th 12.4 14.0 8.4 5 15.3 15.1 9.4 6th 19.8 17.5 10.2 7th 29.7 21.9 10.7 8th 39.8 27.1 9.3 9 46.2 30.2 7.5 10 59.2 37.3 0.5 11th 6 «, 6 42.7 0.3 12th 77.2 47.0 0.2

Serial
No. Burn-off
Weight
percent Acti
fourth water
admission
assets
ml / 100 cm » Desulfurize
solution limit
90 · /,
hours 13th
14th 20.1
20.8 Lumpy
shaped 32.0
21.8 2.0
7.1

It is particularly surprising that both properties are important for flue gas desulfurization - the water-binding capacity and the desulphurisation activity - by deti forming process in change in the same way in a more favorable direction, as in Table 2 by comparing the corresponding Shows data for a peat coke that is once lumpy and the other after it has been formed.

Tubelle L

35

40

With the shaped cokes activated according to the invention, particularly good results are achieved in the successive sequence of SO ₂ adsorption at temperatures between 100 and 200 ° C. and washing with water at temperatures between 20 and 90 ° C. in a continuous cycle. In this way, the burn-up achieved during activation is also retained in the following regenerations, so that, in contrast to thermal regeneration, with its increasing burn-off and thus increasing carbon loss, even over many adsorption and regeneration cycles, no shift into the area of poor desulphurization activity can occur.

The following is the production of the invention * described according to the mold coke used:

1. V part by weight hard coal dust with 23% volatile constituents in a grain size below 60 μ, the oxygen content of which has been increased by 7% by oxidation with air at 300 ° C., are mixed with 23 Oewichü parts of pitch (softening point according to Kramer-S ar η ο w 50 ⁴ C) and 25 parts by weight of water and then kneaded at 100 ° C. The green mass is then pressed into molded bodies about 6 mm thick using an extruder tv. These briquettes are heated to 700 ° C. in a rotary kiln for 30 minutes and then cowed in a vibrating chute. Uteser humkdfci is treated in a gas-heated rotary kiln at 900 ° C. for about 2 hours by passing steam over it and then cooled in a stream of inert gas. The ratio of steam to mold coke is 1.3: 1 kg. With activated molded coke, the burn-up is 28 percent by weight.

2. A shaped coke from oxidized hard coal is produced as described under 1.

This shaped coke is then used for about 7 hours at a temperature of 850 ° C Treated water vapor and burned it off by 30 percent by weight. The ratio of steam to molded coke is 4: 1 kg.

3. 76 parts by weight of a peat coke dust with a grain size of 90 ° / "under 70 μ are mixed with 24 parts by weight of pitch (Kramer softening point - S ar η 0 w 80 ⁰ C) and 25 parts by weight of water and treated further as described under 1. This molded coke was then treated with steam at 800 ° C. for 5 hours, 2.5 kg of steam being added to 1 kg of molded coke. After this steam activation, the burn-up is 20 percent by weight.

4. 80 parts by weight of lignite dust with a grain size of less than 0.1 mm are mixed with 20 parts by weight of pitch (Kramer-Sarnow softening point 58 ° C.) and 18 parts by weight of water as described under 1 and shaped. Thereafter, the blanks are degassed at a temperature of 900 ⁰ C.

This lignite coke is then activated with steam as described in Part 1 up to a burn-up of 20 percent by weight. Its pore volume is then about 52 ^cm3 / 100 g coke.

5. A molded coke produced as described under 1 from pre-oxidized coal is by means of Water vapor activation ahsebrannt by 20 percent by weight.

The following examples show the results when using the activated molded coke in the Desulfurization of exhaust gases described in more detail:

example 1

kg of the molded coke produced according to 1 from oxidized hard coal with a burn-up of 28 percent by weight is arranged in a grain size of 1 to 2 mm in the fixed bed and an exhaust gas of the composition 0.3 percent by volume SO _a , 3.0 percent by volume O ₁ , 6.0 percent by volume H _a O-steam and 90.7 volume percent N hindurihgeleitet ₁ at 120 "C with a residence time of 5 seconds. As soon as the first 100 ° _/? amount of desulfurization end has dropped to 70%, the desulfurization is complete. the activated coke then at a about 90% desulphurisation of the oas quantity which has flowed through 110 g SO, * 168 g M ₁ SO ₄ bound.

The loaded mold coke is sprinkled intermittently at 70 ° C. with 51 ° -70 ° C. hot water, the washing out process being completed after about 1 to 1½ hours. XX) to 330 ml of water remain in the pore volume of the drained molded coke. After 1 rocking the Desulfurization can be carried out again when the coke is at about 120 ° C.

Will turn comparison, the same Oxykoks in the Wa 'efd.iinpfakllvierung bi * to 0 Gh

burned off and 1 kg of this molded coke used for desulfurization as described above, only 20 g SO = 30 g H ₁ SO _{4 are} absorbed.If the bed is washed out with hot water, about 900 ml remain in the moist coke S after regeneration Water back.

Example 2

1 kg of the Formkokses prepared by 2 of oxidized coal with a burnup of 30Ge- wight percent mm with a grain size of 5 as described in Example 1 for Entschwelung at 160 ⁰ C up to 9.5 weight percent (based on the Formkoksgewicht) with SO ₁ , loaded.

The loaded molded coke is washed with 5 l of water at »5 90 ° C batchwise. The drained, moist form of coke holds about 460 ml of water in itself after washing and must be dried for ^{purulent hours at 110 to 120 ° C. before it can be reused.}

Example 3

5 kg of the molded coke produced according to 3 from ground peat coke with a burn-up of 20 percent by weight are in a grain size of 4 to 6 mm from an exhaust gas from a heavy oil furnace with 0.1 volume percent SO ₁ at 140 ⁰ C with a residence time of 6 seconds flows through. In a Eutschwefelungsgrad of 70% ^w> desulfurization rd finished. The bed has then taken up 140 g SO ₁ = 215 g H ₁ SO ₄ .

The adsorbed sulfuric acid is washed by a countercurrent washing with water about 201 of 6O ⁰ C. During this regeneration, the molded coke absorbs about 2.31 water. For drying, the flue gases at around 145 ° C flow through the shaped coke bed again, the desulfurization temperature dropping to 100 to HO ⁰ C over a _{period of around 2–1 hours.}

B e i s ρ i e 1 4

1 kg of the lignite coke produced according to 4 with a burn-up of 20 percent by weight is treated with a grain size of 1 to 2 mm as described in Example 1 in a fixed bed arrangement up to a degree of desulphurization of 70%. The molded coke then has taken up 45 g SO = 68 g H ₁₁ SO ₄ . The washing out is also carried out in the manner described in Example 1. The washed, wet coke about 400 ml of water are left behind which must be removed by drying at 120 ⁰ C, to be able to use the coke in the next adsorption-regeneration cycle.

Example 5

5 kg of the molded coke produced according to 5 from oxidized hard coal with a burn-up of 20 percent by weight are loaded _{with SO 1} or H ₁ SO _{4 in a grain size of 4 to 6 mm in a solid layer as described in Example 3.} The bed then absorbed 45 g SO »= 680 g H ₁ SO _4.

The washout succeeds; also in the manner described in Example 3. The molded coke contains 1.6 1 water, which by drying with the 145 ° C hot Flue gases is removed.

Claims (2)

Patent claims: 1. Use of a molded coke as an adsorbent for sulfur oxides from exhaust gases, which is obtained by mixing powdery, non-baking, fossil or recent fuels with a grain size of 100% below 1.0 mm, preferably below 0.1 mm, with about 15 to 35 percent by weight of bitumen, tar or pitch as a binder, molding the green mass and degassing has been prepared at temperatures of between about 500 and 900 ⁰ C according to patent 1,283,807, characterized in that the devolatilized coke with steam at temperatures between 800 and 1000 ⁰ C is activated. 2. Use of a molded coke according to claim 1, characterized in that the steam activation is carried out until the coke burns up between 10 and 30 percent by weight.