DD236437A3 - METHOD OF GENERATING ACTIVATED CARBONS FROM MULTIPLE LOADS OF SPINY BROWN COAL GASIFICATION - Google Patents

Abstract

The invention relates to the production of activated carbon from Multiklonstaeuben lignite gasification in a fluidized bed. The object of the invention is to improve the adsorption properties by suitable selection and combination of mechanical treatment stages. The multiclonal dust is separated by a sieving into 3 fractions: 1. 100 mm 2. 100-250 mm 3. 250 mmThe first fraction is discarded, the second fractioned by air classification into a residue and an overflow. The overflow is combined with the 3rd fraction 250 mm and treated together with 25% hydrochloric acid while passing through air. If fumigated with carbon dioxide, a 10% hydrochloric acid can be used. The product thus produced is washed neutral with water and then dried. It is still possible to process only the screened fractions, but this does not achieve product quality.

Description

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The said processes have the disadvantage that the starting product is used unfraked and thus higher expenses incurred in the proposed process stages, because to achieve an attractive activated carbon, the ash content of the starting materials must be removed as much as possible.

Object of the invention

The aim of the invention is to use the dusts produced in large quantities from the Winkler generators for the production of adsorbents while increasing the adsorption capacity.

Explanation of the essence of the invention

The object of the invention is to process the dusts so that their use in adsorption processes, eg. As the water purification is possible. Furthermore, by choosing a suitable technology, the expenses for the treatment process, in particular the acid wash, can be significantly reduced. The investigations of the multiclonal dusts accumulating behind the actual generator showed that there is a pronounced dependence of the carbon content on the particle size of the dust. Subsequently, the insecticide dust was divided into four particle size classes by sieving and analyzed by special methods. The following results were achieved: '"

grain sizes C-content iodine BET surface Phenoladsorption surface m % mg / g mVg mg / g at 200 mg / l 1 . unscreened 61.6 440 417 69.2 2. <56 46.5 281 229 39.5 3. 56-100 56.3 546 391 59.5 4. 100-250 61.9 656 472 73.0 5.> 250 67.4 634 446 71.2

This result is surprising insofar as the coarse sieve fractions, contrary to expectations, have a larger surface area and therefore better adsorption properties than the smaller particle size classes. It was therefore natural to isolate the particle size fractions 100-250 μm and> 250 μm and further improve them by acid treatment. This allowed the iodine numbers to be increased to about 750 mg / g; The carbon content reached 87 to 91% in both fractions. It is more expedient to subject the sieved dust to an air classification before, as this causes the specifically heavy dust particles to be removed.

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chen, which have the same size, a higher content of inorganic impurities, can be separated.

The air classification revealed an increase in the iodine number to 795 mg / g in the grain class 100 to 250 μm after washing with 25% hydrochloric acid, the BET surface area to 1 210 mVg and phenol adsorption to 105 mg / g. This achieved the values of a good activated carbon.

embodiments

1. The multiclonal dust is separated by sieving into 3 fractions:

<100 um = 24% discarded

100-250 μm = 56% wind, wash> 250 μm = 20 % wash.

The 100 to 250 μm fraction is spotted at a flow rate of 4,400 air in a glass column 65 mm in diameter and 350 mm high with melted G 3 frit for 15 minutes. 45 % are discharged and 55 % remain as residue, based on the mass of the original fraction. The discharged material is added to the fraction 250 um, treated with 25% hydrochloric acid, then washed neutral with water and dried. From the original Multiklon dust 40 to 45 Ma. -% obtained as activated carbon ..

2. Both the unswept Winkler dust and the individual sieve fractions are washed with 10 and 25% hydrochloric acid. Per kg Winkler dust 5-7 kg of the respective acid are needed. The mixture is stirred vigorously by passing in air. After 36 hours washing time, the following result was obtained:

Washing solution Iodine number mg / g Surface values BET mVg Phenolads. mg / g at 200 mg / l Grain. m 10 % HCl 25 % HCl 599 646 Benzolads. mVg 496,674 75 78 Unsetich tet 10 % HCl 25% HCl 689 755 _ 522 679 cn cn cn cm VD O 79 83 100-250 10 % HCl 25 % HCl 684 744 725 739 1 016 1 045 72 77 250 -

Wash solutions with. Various levels of sulfuric acid, nitric acid or with sodium hydroxide brought worse results than with hydrochloric acid.

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3. In order to determine the possible influence of the stirring technology on the adsorption capacity, the following tests were carried out. The fraction 100-250 μm was dispersed in 25% hydrochloric acid and

a) with air. '

b) with a paddle stirrer

c) with nitrogen d). with carbon dioxide

e) treated with carbon dioxide but 10% hydrochloric acid for 36 hours

 The following result was obtained:

iodine benzene adsorption Phenoladsorption mg / g mVg mg / g at 200 mg / l a 753 730 86 b 670 701 72 C 655 689 70 d 760 790 93 e 758 799 91

It can be seen from the test result that the best results are achieved with COp stirring, with no significant difference between the use of 10% or 25% hydrochloric acid. Compared to air agitation, the results of experiments d and e are better, especially in the values of benzene adsorption. The values of b and c are significantly worse.

4. In Examples 3 and 4, wash times were 36 hours. This time had been determined from experiments that gem. Example 2 were carried out and were sampled first after 10 hours and then every 5 hours thereafter. The samples were examined for iodine number and benzene adsorption. After 36 hours, these indicators changed only insignificantly. The same experiments were gem. Example 3 e, thus employed with COp stirring. : Already after 17-19 hours the values of Example 3 e were reached. COp stirring thus not only causes a saving of hydrochloric acid (use of 10% instead of 25% HCl) but the COp stirring also shortens the washing process by about 50 %.

Claims (3)

- 1 - _> 206 Invention claims: 1. A process for the production of activated carbon from Multiklonstäuben the fluidized bed lignite gasification, characterized in that the MuItiklonstaub a separation into three grain fractions, preferably by sieving, subjected to the middle fraction further divided by air classification and the overflow of air classification together with the coarsest sieve fraction in known manner is freed by acid washing of ash parts. 2. The method according to item 1, characterized in that the Multiklonstaüb in the screening in the grain fraction <100 um,
100 to 25Q around and > 250 um
is decomposed. 3. The method according to item 1, characterized in that for acid washing by a gas vortexed hydrochloric acid, preferably 10% hydrochloric acid is used with simultaneous fumigation with carbon dioxide. Field of application of the invention The invention relates to a process for the production of powdered activated carbon from the multiklon dusts of fluidized bed lignite gasification. Characterization of the known technical solutions Brown coal gasification in the Winkler generator produces a relatively high-carbon dust which has a BET specific surface area of> 00 to 500 mVg. A disadvantage is the high content of predominantly sulfidic sulfur and the ash content, which prevents a direct use of this dust in the Adsorptionstechnik. The removal of the interfering components can be achieved by subjecting these dusts to acid treatment and desulfurization. Also a treatment with aqueous alkalis is proposed (DDR-PS 21 209). In a further process according to GP C 01 B / 196 866, these so-called Winkler dusts, Winkler ash or mixtures thereof and / or the products from the Winklergaserzeugung downstream process stages subjected to acid treatment, washed with water and then optionally dried and ground. This is an activated carbon to be produced, which can be used in a variety of applications such as drinking water treatment, chemical and pharmaceutical industries.