DE2024210C3 - Process for the production of adsorption carbon - Google Patents

Description

The quality of adsorption materials such as adsorption carbon is measured by the size of the surfaces and micropores accessible for adsorption, the maximum accumulation per adsorbent weight, the adsorption speed and the abrasion resistance of the substance, which is associated with the handling of the same within the technical apparatus For an important application of such adsorbents, namely the removal of harmful constituents from flue gases, the ignitability of the adsorption carbon also plays an essential role.

It is known that the aforementioned properties are not only due to the properties of the starting material, but to a large extent also through the measures used in the production of the adsorption carbon to be influenced. It has been shown that - starting from cheap carbon carriers such. B. Brown coal peat or wood - high-quality adsorption cokes, which are also used by application technology required conditions of the large specific surface, the high adsorption rate, the high strength and the ignition temperature are sufficient, not achievable with the) known manufacturing processes are.

This applies e.g. B. for a method known from US-PS 21 66 255, in which coal or cellulosic material undergoes a two-stage treatment, with a drying process during the first stage includes, a slight overpressure should be advantageous. The end product that can be achieved in this way corresponds does not meet the quality requirements listed above.

From CH-PS 97 252 a process for the production of active charcoal from charcoal is known, in which the charcoal is subjected to negative pressure before impregnation with alkali and afterwards Performing the impregnation the material is heated to high temperatures and then washed out. Here, the negative pressure only serves to intensify the impregnation process.

The invention is based on the object of a method for the production of adsorption carbon provide that allows high-quality adsorption carbon to be produced from cheap carbon carriers. Included the adsorption carbon should also be suitable for cleaning flue gases and a correspondingly high level Have ignition temperature.

This task is performed in the process for the production of adsorption carbon, in which a carbon

example 1

(without treatment according to the invention)
Rrhbrauiikchleder the following composition

Fixed carbon 21.8% Volatiles 24.5% Water content 52.0% Ash content 1.7%

with a grain size of less than 10 mm was exposed to a stream of air on a sieve bottom one Had a speed of 0.024 m / s at a temperature of 65 ° C. The convective drying took place at normal pressure through the air from 12.6% moisture to a coal moisture of 5% (drying time: 160 Minutes).

The coal dried according to the method described above was then heated in a heated muffle at a rate of 10 ^° C. per minute to a final coking temperature of 1000 ^° C. and held at that temperature for 180 minutes.

The coke was cooled in the same muffle with the exclusion of air for a cooling time of 60 minutes. It became an adsorbent carbon obtained with the following properties:

Specific surface area 173.48 m ² / g

Cm ³ N ₂

Adsorption rate .... 1.26

g coke min

Ignition temperature 289 ° C

Sieve passage after static
Pressure load
(Grain size 1 mm) 32.11%

Example 2
(with treatment according to the invention)

The same raw brown coal as used in Examples 1 and 2 was used in the same Drying apparatus as in Examples 1 and 2 predried to a water content of 5%. The pre-drying time was 160 minutes.

The pre-dried coal was then under a vacuum of 1 Torr for a period of 15 Minutes completely dried. The final water content of the coal was 0.5%.

The dry carbon was heated in the same muffle as in Examples 1 and 2 with a heating rate of 1O ⁰ C per minute while maintaining a negative pressure "/ on 1 Torr. The Erhitzui '^ end temperature was 1000 ⁰ C. At this temperature the coke at the same underpressure over 180 minutes was maintained.

The adsorption carbon produced had the following properties:

Specific surface area 326.24 nrr / g

Adsorption rate .... 3.54; —r- --.-

g coke min

Ignition temperature 377 "C

Sieve passage after static

Pressure load 36.55%

The specific surface area was measured by the BET method, and the ignitability was measured in a

15 through-flow apparatus was determined as the ignition point in the oxygen stream, and the bulk compressive strength was determined by loading a bulk bed 13 mm high from a grain fraction between 4 and 5 mm with a pressure of 40 kp / cm.

In the drawing is an embodiment of the Invention shown in connection with the production of adsorption coke.

As the figure shows, the raw lignite is exposed to heating media 2 at 1 Tube dryer 3 burnt in. After expelling the steam 4, the predried brown coal is 5 after-dried in the tube vacuum dryer 6. From the tube vacuum dryer 6, which is heated by heating media 2, the post-dried Lignite 7 and the steam 4 withdrawn. The post-dried brown coal 7 is in the vacuum shaft coker 8 introduced, which is heated externally by heating media 2. From the vacuum shaft coker 8 the coking exhaust gases 9 and the adsorption carbon 10 emerge.

1 sheet of drawings

Claims (1)

Claim: Process for the production of adsorption carbon in which a carbon carrier with high bound water content, such as lignite, peat or wood, which is treated in two stages, the first of which is the Expulsion of the water and the second stage of expulsion by thermal decomposition resulting gaseous constituents is used, d a characterized in that the treatment takes place in at least one of the stages at reduced pressure to below 1 gate r It is assumed that a carrier with a high bound water content, such as lignite, peat or wood, is found in two stages is dealt with, of which the first stage the expulsion of the water and the second stage of expulsion of the thermal decomposition gaseous constituents is used according to the invention in that the treatment in at least one of the steps is carried out at reduced pressure to below 1 torr ίο The adsorbent carbon produced in this way has a large specific surface area, which leads to a correspondingly favorable adsorption rate This also has the consequence that the ignition temperature is higher than when using known methods. is The following examples and the illustration are for Explanation of the invention.