DD207183A1 - METHOD FOR PRODUCING WATER AND GAS CLEANING ACTIVATED CARBON BONE CARBON - Google Patents

Abstract

The Eerfindung relates to a process for the production of activated carbon form from lignite, which can be used for the purification of noxious gases, solvent fumes from air and / or water. The aim and object of the invention is to develop a process for the production of form coal from raw lignite, whereby the carbon skeleton is better digested by an appropriate treatment for the activation. The essence of the invention is that grave-fed raw lignite pre-dried to moisture contents of 20% at 40-120 degrees, extracted with organic extractives for 1 to 3 hours, dried after separation in air or treated with finely divided water vapor, then with 20-70 Ma-% Saegemehl and a zinc chloride solution in the ratio of dry solids of 1: 1 mixed to 2: 1, then granulated and activated for 3 to 8 hours at 600-750 degrees in a reducing or inert gas atmosphere and optionally ground.

Description

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Title of the invention

Process for the preparation of water and gas purification activated carbons from lignite

Field of application of the invention

The invention relates to a process for the production of activated carbon form lignite, which can be used for the purification of noxious gases, solvent vapors from air and / or water.

Characterization of the known technical solutions

It is well known that activated carbons for gas and water purification purposes can be produced from lignite by partial coking or treatment with inorganic acids and subsequent activation.

According to DD-PS 142 175, coal is formed into small grains, which are then treated with phosphoric acid to reduce the content of volatile components and increase the content of carbon. The product is then dried, mixed with a carbonaceous binder, comminuted or pulverized, the powder pressed into molds and activated.

The DD-PS 126 638 assumes that brown coal is crushed, sieved and then treated with 5% aqueous sulfuric acid. The suspension is heated at 80 ° C. for 5 hours, then decanted and the solid is dried. This is followed by screening, the undersize "c 0.043 mm is pressed into pellets and activated in a reducing atmosphere.

Similar methods are also described in DD-PS 128 621. Here brown coal is crushed treated with an approximately 10% inorganic acid, pulverized and the powder pressed into pellets. The pellets are crushed, the receiving grains are freed from volatile material and activated.

DD-PS 141 154 gives activated carbons which are coked and activated thermally from lignite granules after prior treatment with acids (eg sulfuric acid, hydrochloric acid or phosphoric acid) in an oxygen-free atmosphere.

DD-PS 140 241 describes a process for the production of granulated coal by treating grains produced from lignite with a dilute aqueous solution of an inorganic acid. This is followed by drying, pulverization, granulation, coking and activation of the carbonaceous product.

The above-described processes have the disadvantage that only inorganic lubricants, such as alkali metal and alkaline earth metal compounds, are leached out by the use of inorganic acids. As a result, the carbon skeleton for activation is not "unlocked". The mineral constituents have a positive effect on the skeletal structure of the activated carbon even during activation. Existing hydrocarbons of medium and higher molecular weights remain in the structure of the coal, decompose on thermal treatment of the carbon support to oligomers or Verharzungsprodukten and clog the resulting during the activation process pores (Franke, FH, Jäger, RI, Heraikib, M. Chemie-Ingenieur Technik, 4 ^ (197D 1017 - 1022) This often does not achieve the required quality of the activating process.

Object of the invention

The aim of the invention is to develop a form activated carbon from raw lignite, which has a higher activity compared to the known technical solutions.

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Presentation of the nature of the invention

The invention has for its object to develop a process for the production of activated carbon form raw lignite, whereby the carbon skeleton is better digested by an appropriate treatment for the activation.

According to the invention the object is achieved in that raw lignite ground to a particle size of 0.5 to 10 mm and dried to a residual moisture content of 12 to 20 % . This is followed by extraction with benzene, toluene or xylene bzv / for 1-3 hours. mixtures thereof or in admixture with methanol, ethanol or acetone at 40-120 ° C., preferably at 70-110 ° C. This removes excess organic constituents such as hydrocarbons and hetero compounds. High molecular weight low volatility constituents such as tar and 3itumen shares with high carbon content remain in the grain and become part of the later carbon skeleton. The extractive solvent or mixture used is recovered by distillation and the extract is fed to a suitable use. Mach extraction done, the resulting intermediate is dried in air or treated with finely divided V.'asserdampf. Then the oversize is sifted> 1 mm or ground if necessary. The undersize is mixed in a manner known per se with 20-70% by weight of sawdust and a zinc chloride solution in relation to the dry solid of 1: 1 to 2: 1, then granulated and 3-8 hours at 600 - 750 ° C in reducing or Inertgasatmosphäre activated. The resulting carbon can be ground and used as powdered coal.

embodiments

The invention is explained below with reference to 3 examples:

Comparative example

Mining wet lignite was comminuted to a particle size of 0.5 to 6.0 mm and dried to a moisture content of 15 to 20 % . 70 cnr of this coal were placed in a Soxhlet extraction apparatus and extracted with 10% aqueous sulfuric acid solution at 115 ° C for 120 min, the extracted carbon washed with water and again to 15 to 20 % moisture content.

salary dried. 60 g of the so-treated coal are ground to a particle size of <0.5 mm, mixed and compressed with 50 6 sawdust (16.9 % moisture ) and 223 g zinc chloride solution (density 1.92 g / cm ³ ).

The activation took place for 4 hours at 700 ° C. in a shaft furnace in an inert gas stream. After acid and water washing, an activated carbon having the following properties was obtained:

Benzene adsorption at 10 % by volume benzene (g benzene / 100 ml charcoal) 7.4 iodine value (mg J ₂ / g) 485

Methylene blue titre (ml) 6,9

Molasses value (mg) 1350

Example 1

60 cm- ^ of the raw lignite described in Comparative Example were extracted in a Soxhlet apparatus 90 ° with an ethanol / benzene mixture (1: 1) at 80 ° C and. The extracted product was air dried for 2 hours or treated with finely divided water vapor at 120 C for about 20 minutes. 40 g of the coal thus treated were ground to a particle size <Ü, 5 mm, with 35 S sawdust (moisture 18.9 %) and 155 S zinc chloride solution (density 1.92 g / cm-0 mixed and pressed.

Activation was again carried out for 4 hours at 700 ° C in a shaft furnace in an inert gas stream. After the aftertreatment described in Example 1, an activation product with the following properties was obtained:

Benzene adsorption at 10 vol% benzene

(g benzene / 100 ml charcoal) 12,6

Iodine number (mg / J ₂ / g) 715

Methylene blue titer (ml) 14,8

Molasses value (mg) 580

Example 2

60 ctü of crude lignite used in Comparative Example were extracted in a Soxhlet apparatus for 60 min with toluene at 110 ° C, the extraction residue dried in air or treated with steam. 50 g of the coal thus treated were ground to a particle size of 0.5 mm, with 72.3 g of sawdust (moisture

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30.6%) and 223.5 S zinc chloride solution (density 1.92 g / cnr) mixed and pressed.

The granules were activated for 4 hours at 700 ° C in a shaft furnace in an inert gas stream and post-treated analogously to Example 1. The produced activated carbon had the following properties:

Benzene adsorption at 10 vol% benzene

(g benzene / 100 ml charcoal) 14.8

Iodine number (mg J ₂ / g) 835.2

Methylene blue titre (ml) 18.1

Molasses value (mg) 420

Example 3

60 cm- ⁵ of the raw lignite coal used in the comparative example were extracted in a Soxhlet apparatus for 90 min with an acetone / toluene mixture (1: 1) at 110 ° C and the extracted product dried in air for 2 hours or treated with steam. 50 g of the coal treated in this way were ground to a particle size of 0.5 mm, mixed with 62 g of sawdust (18.9 % moisture) and 232 g of zinc chloride solution (density 1.92 g / cm 2) and pressed.

The resulting product was activated for hours at 700 ° C in a shaft furnace in an inert gas stream. After acid and hate scrubbing, the activity had the following quality parameters:

Benzene adsorption at 10 vol% benzene

(g benzene / 100 ml activated charcoal) 13.5

Iodine number (mg J ₂ / g) 771

Methylene blue titer (ml) 17.5

Molasses value (mg) 515

Claims (5)

238 0 06 0 Invention claim. 1. A process for the preparation of water and gas cleaning activated carbons from lignite characterized in that pit-dried raw lignite pre-dried moisture contents of ^ = 20 % at 40 - 120 ° C, extracted with organic extractive solvents 1 to 3 hours, dried after separation in air or treated with finely divided V / a ^ steam, then mixed with 20 - 70% by weight of sawdust and a zinc chloride solution relative to the dry solid from 1: 1 to 2: 1, then granulated and 3 to ö hours at 600 - 750 ° C in activated reducing or inert gas atmosphere and possibly ground. 2. A process for the preparation of water and gas cleaning activated carbon according to item 1, characterized in that the predrying of the raw lignite is preferably carried out at 70 - 110 C. 3. A process for the preparation of activated carbon and gas cleaning activated carbon according to item 1, characterized in that benzene, toluene or xylene or mixtures thereof or in admixture with ethanol, ethanol, or acetone are used as the extractive solvent. 4 ·. Process for the preparation of water and gas cleaning activated carbons according to item 1, characterized in that the extractive solvent or mixture is recovered by distillation. Process for the preparation of water and gas cleaning activated carbons according to item 1, characterized in that the extracted product is preferably mixed with 40-60% by mass of sawdust and a zinc chloride solution, preferably in the ratio of 1.3: 1 to 1.6: 1.