DE2461165A1 - Increasing the sorption capacity of active carbon - by heating in inert gas and subsequent indirect cooling - Google Patents

Abstract

In a process for improving the sorption capacity of active carbon by heating and subsequent quenching in a cooling medium, the carbon is first heated to a temp. in the region of 50-300 degrees C and then quenched to a temp. of below minus 66 degrees C by heat transfer through a dividing wall by a quantity of the coolant. The heating process is pref. carried out in an inert atmosphere, and the cooling is pref. carried out such that the temp. falls at a rate of 90-400 degrees C per minute as far as 0 degrees C. Cooling can be effected by a combination of condensation of inflowing inert gas with the joule thompson effect. In comparison with existing techniques the resultant carbon has a greater hardness and reduced particle size reduction due to thermal shock, whilst sorption capacity is equal or better. Inert gas excludes unwanted reactive gases, and controlled cooling rate gives reproducible results.

Description

Title: "Method and device for improving sorbent capacity of activated carbon. " The invention relates to a method and an apparatus to improve the sorption capacity of activated carbon.

From British patent specification 1,263,603 it is well known that the sorption capacity of inorganic sorption means by heating up to a temperature above 300 C and subsequently quenching to a temperature less than -75 C. The sorption itself usually takes place at room temperature or a slightly higher temperature.

The term "sorption" is understood to mean both physical sorption including capillary condensation as chemical sorption.

With the above-mentioned activation process according to British patent specification 1,263,603 is used during the quenching of the relevant sorbent in a liquefied gas submerged in order to achieve a very rapid cooling.

During the experiment, however, it has been shown that such a rapid cooling impregnated activated carbon pulverization of the carbon or impregnation and this also causes a reduction in the sorption capacity.

The invention is therefore based on the object of the above To improve processes in such a way that the aforementioned pulverization is avoided, and at the same time the treated activated carbon is one in comparison to the known activation processes unchanged or increased sorption capacity achieved.

The solution to this problem is given according to the invention, that the raw material is first placed in an inert atmosphere up to a temperature in the range 50-300 C and then by means of heat dissipation through a partition on a quantity of cooling medium quenched on the other side of the wall to a temperature of less than -66 C. will.

The inventive cooling through a partition, e.g. a pipe wall, is advantageous in that impregnated carbon particles are not distributed and maintain their hardness, and at the same time an increased sorption improvement can be achieved. These benefits achieved are essential at Gas filter devices for shelters, chariots etc. In these cases are namely the resistance of the coal particles to fragmentation, especially under Exposure to shocks and viberations, very important.

As a measure of such resistance to breaking or grinding of the coal particles is such an average particle size used that by Milling and subsequent sieving according to the following procedure is achieved. This mean particle size is defined by the following formula (K. Winnacker, E. Weingärtner, Chemical Technology, Volume I, S 52, 1950>: = e (x / x) n 100 (1), or 100 log (log R) = nlogx - nlogx + log loge (2).

In a logarithmic coordinate system, equation (2) gives a straight line.

R denotes the percentage by weight of the total amount of particles, which is not a sieve with a mesh size equal to x mm.

can penetrate.

n denotes the slope of the straight line and is a measure of the Homogeneity of the coal particles.

R denotes the statistical mean diameter of the particles.

Record the appropriate values of R and x in a double logarithmic Coordinate systems gives a straight line, and the mean particle diameter x corresponds to R = 36, o 'The invention relates to a device for improvement the sorption capacity of activated carbon through heating and subsequent quenching by means of a cooling medium when performing the above method.

This device according to the invention is characterized in that a vertically mounted tube furnace for heating the activated carbon in an inert atmosphere is arranged above a cooling chamber, which is carried by a cooling medium container a partition is separated, the tube furnace with the cooling chamber by a closable pipe connection for transferring the heated activated carbon by means of Gravity is connected to the cooling chamber when the pipe connection is opened.

The device is excellently equipped in such a way that the RWhlkammer ring-shaped and both inside and outside the ring shape of the Kühlmediumbehalter is separated by the partition.

With moderate quenching of activated carbon in a cooling chamber you can the following advantages can be achieved: a) The coal particles achieve a higher sorption capacity as activated carbons which are activated by previously known methods.

b) The hardness of the activated carbon is retained and corresponds the hardness of the raw material.

c) Regulated inert cold atmosphere (e.g. H2, He, Ar) the undesired excludes reactive gases.

d) Regulated cooling rate that enables reproducible properties.

Other features of the invention, as well as properties and uses of the carbon product produced are illustrated in the examples below.

Example 1 Physical sorption as a function of the cooling rate (0C½min.) The present example shows the chloropicrin uptake of Cu-Cr-Ag-impregnated Coal as a function of the cooling rate. The coal is of the Pittsburgh type ASC 12 X 30 and is preferably used for the production of gas masks that are used for Serve protection against war gas such as chloropicrin. Five coal samples were taken during 2 Hours activated at a temperature of 168 q 50C. 4 of the samples were taken in 30 cm long thin-walled steel pipes of different diameters filled, such as given in Table 1. The tubes were placed in a cylindrical oven. The temperature was measured by means of a thermocouple placed in the center of the Coal layer had been applied. The temperature fluctuations on a 20th mV recorder registered. The quenching process was carried out so that each tube individually removed from the oven and quenched in liquid nitrogen. The samples were taken during the activation as well as during the chopping process flushed with nitrogen gas. All samples were kept in liquid nitrogen until the lowest temperature of approx. - 190 ° C was reached. The coal was taking on it Nitrogen purging warmed to room temperature, and in plastic bottles in a nitrogen atmosphere kept until a capacity test is carried out.

The temperature rate is defined here as OC / min. in the temperature range 168 - OOC.

The cooling curve observed was linear in this temperature range.

The charcoal in sample No. 5 was in a steel tube with perforated Walls attached. Pipe diameter: 18 mm.

During this quenching process, the liquid nitrogen was in direct contact Contact with the activated carbon. This resulted in a much faster cooling rate than with the other four samples. This sample was also constantly with @Nitrogengas surrounded and washed through.

75 ml of all samples were tested with chloropic ring gas. As from Table 1, the volume of coal in tubes 1 and 2 is too small for one Chloropicrin test. In order to get enough coal volume for the picrine test, activated three samples from each of these two tubes.

The capacity measurement was carried out so that 150 mg / min. Chloropicrine diluted with 28.5 L dry air over a bed of coal of the following dimensions was conducted.

Volume: 75 cm33 Area: 30 cm Height: 2.5 cm Linear speed: 10 m / min.

The breakthrough of the gas was shown on a color indicator. When a concentration of 10 ppm was reached, the indicator turned yellow. Table 1 shows the test results and the test conditions. Tube Inn Active Cooling Cooling Chlorine Chlorine Capacity xx No. of coal-time rate picrine picrine change Tube volume capacity capacity diam. in the pipe mm cm³ min. ° C / min. Min./ml mg / ml% 0 - - - - 0.70 105x 0 1 12.4 35, o, 6o 280 o, 88 132 +25> T 2 | 15.4 | 49, - | 0.70 | 233 | 0.83 | 124 | +18.1 3 19.2 78, - 1.20 140 0.76 114 + 8.5 4 25.0 129 2.20 76 0.56 84 # 20.0 5 22.0 80, - 0.38 429 0.53 80 # 23.8 x original charcoal. Average capacity of 8 measurements. Rel. Standard deviation + xx change in capacity compared to the original carbon.

The table shows that an increased quench rate increased Sorption capacity. Experiment no. 5 shows that direct cooling with the highest cooling rate does not lead to the highest increase in capacity. The controlled Cooling in pipes has the advantage of preventing the coal from glowing up. ASC During the activation process, coal glows in contact with air at 160 ° C, which is an abnormally low ignition temperature. The experiments suggest that an optimal cooling rate leads to the highest capacity. This rate is below 429 ° C / min., But above approx. 760 ° C / min.

Example 2 Table 2 shows the particle size distribution of the original products shown, both quenched (BK) and slowly cooled (LK) granules the coal types Pittsburg ASC (ASC), Sutcliffe Speakman 607 (SS 607). The deterrent process takes place in a metal tube with a diameter of 18 mm, as described in Example 1.

Table 2 Coal Cooling Active types process ization weight distribution (%) of the particle size temperature ° C 3.36 mm 2.00 mm 1.00 mm 0.50 mm ° C 3.36 mm 2.00 mm 1.00 mm 0.50 mm ASC original 63.3 36.7 ASC AS in tube 160 49.4 50.6 ASC AS in fl.N2x 160 47.2 52.8 ASC LA in tube 160 61.7 38.3 ASC AS in tube 300 52.2 48.8 ASC AS in fl.N2 300 AS in the pipe ASC 375 47.4 52.6 SS 607 original 9.2 88.0 2.8 SS 607 AS in tube 160 @, 7 88.1 SS 607 | | 160 | 4.5 | 87.8 SS 607 AS in tube 300 6.2 87.3 SS 607 | | 300 | 4.8 | 87.8 607 AS in pipe 383 5.4 88.7 5.9 x in fl.N2: in liquid nitrogen LA = slowly cooled AS = quenched coal From Table 2 it can be seen that the scraping process in tubes with activated granules up to 300 C does not significantly shift the granulate size towards smaller particle size or dust. Consequence. This means, for example, that the pressure drop over a bed with (AS) activated carbon is not higher than over a bed with the same dimensions made from original carbon.

The resistance of the granules it was crushed by crushing it measured in an analytical mill, which comes from a room with a horizontally rotating Steel knife existed. The rotation speed was 20,000 rpm. 10 grams of each sample was crushed for 2 seconds and then sieved by means of of a test sieve of the type: test sieve DIN 4188. The results are given in Table 3.

It can be seen from Table 3 that the activation and the quenching directly in liquid nitrogen, as well as heating the coal in pipes above 300 C. and subsequent quenching also to reduce the mean particle size leads.

The numbers given, # 4.4% and # 3.2% correspond to the relative Standard deviations in repeated attempts at the crushing and sieving processes of the respective original coal types.

It can also be seen from Table 3 that quenching in pipes is less Reductions in the mean particle diameter x as quenching directly in liquid Nitrogen.

Table 3 Weight distribution of the particles Attempt Coal Cooling Active Medium big change No. Types process ation particle el- d. intermediate diameter temp->3.36>2.00>1.00>0.50> 0.50 Particle el- mm mm mm mm mm erature x mm diameter x ° C% 1 ASC original 39.5 42.4 18.1 1.00x 2 ASC AS in tube 160 39> n 4) 4.6 16.4 1.00 O 3 ASC As in fl.N2 160 26.0 52.6 20.5 0.91 - @, 0 4 ASC LA in tube 160 23.0 47.4 29.6 0.72 -28.0 5 ASC AS in tube 300 31.2 47.8 21.0 0.95 -5.0 6 ASC AS in pipe 375 25.8 47.4 26.8 0.87 -13.0 7 SS 607 original 0.7 36.7 32.5 30.1 2.00xx 8 SS 607 AS in tube 160 2.0 32.3 32.0 32.7 1.97 -1.5 9 SS 607 AS in fl.N2 160 1.8 32.9 33.9 31.4 1.87 -6.5 10 SS 607 AS in tube 300 1.5 34.3 33.0 31.2 1.97 -1.5 11 SS 607 AS in fl.N2 300 0.9 32.5 34.9 31.7 1.90 -5.0 12 SS 60r AS in tube 383 1.1 33.5 33.9 | 31.5 1.89 ~ 5s5 AS = quenched coal LA = slowly cooled. Example 3 This example shows the physical sorption capacity of CuCrAg-impregnated coal of the Pittsburgh ASC 12 X 30 type, which has been activated in the temperature range 110-800 C and quenched in pipes. For comparison purposes, activated carbon and slowly cooled in tubes, as described in Example 1, is also listed. The capacity of the carbon was tested with chloropicrin, under the same conditions as described in Example 1. The impregnation has the following composition: Cu 6%, Cr 2%, Ag 0.05%. These elements are in the form of salts, oxides and hydroxides on the surface of the coal. The results are shown in Table 4.

Table 4 Attempt Activation Capacity Capacity Capacity temperature LAx ASxx changexxx% No. ° C min / ml mg / ml min / ml mg / ml LA AS 105.0 0.70 0.70 105.0 0 o 1 - 0.70 105.0 0.70 105.0 0 0 2 110 0.35 52.5 0.51 76.5 # 50.0 # 27.2 3 130 0.82 123.0 0.97 145.0 +17.1 +38.0 4 160 0.62 93.0 1.12 168.0 # 11.4 +60.0 5 200 0.67 100.0 1.04 156.0 # 4.7 +48.5 6 250 0.75 112.0 0.88 132.0 + 6.6 +25.7 7 300 0.67 100.0 0.80 120.0 # 4.7 +14.3 8 400 0.78 117.0 0.80 120.0 +11.4 +14.3 9 800 - - 0.28 41.0 - # 61.0 x capacity as a result of slow cooling LA xx capacity as a result of quenching AS xxx change in capacity compared to the capacity of the original coal, experiment No. 1 Table 4 shows that the quenching process (AS) in pipes results in an increase in the chloropikrin capacity, if the carbon was activated at temperatures below 300 ° C, especially in the temperature range 160-200 ° C. Activation above 300 ° C followed by quenching gives very little increase or even a decrease in capacity. Comparative tests with slow cooling tA) generally lead to a slight increase in capacity and in some cases to a reduction in capacity compared to the original product.

Example k In the example below, the activation: urid Quenching was shown to increase the chemical sorption capacity. The coal and the activation method are the same as described in Example 3.

Cyanogen chloride (CICN) has been used as a typical chemisorbing gas. It can be assumed that cyanogen chloride reacts with the impregnation (Cr) according to the following scheme: The presence of water molecules is required. Sorbed or chemically bound water must therefore be present so that the oxidation can take place.

The measurement of the cyanogen chloride capacity of the activated carbon was taken under made the following conditions: carbon volume in filter: 75 3 filter area: 30 cm bed height: 2.5 cm total gas volume: 3O 1 / min.

Linear speed: 10 m / min.

Carrier gas: air Relative humidity: 0% cyanogen chloride dosage: 72-3 mg / min.

Filter temperature: 18 # 0.2 ° C The breakthrough of the cyanogen chloride gas was checked by means of a color indicator.

The results are shown in Table 5.

Table 5 Attempt activation LAx ASxx capacity changexxx temperature Cyanogen chloride capacity Cyanogen chloride capacity LA AS No. ° C min / ml mg / ml min / ml mg / ml%% 1 - 0.180 12.90 0.180 12.90 - - 2 110 0.120 8.65 0.060 4.30 -33.3 -66.7 3 130 0.130 9.35 0.145 10.40 -27.8 -19.4 4 140 0.130 9.35 0.185 13.30 -27.8 + 3.1 5 160 0.132 9.50 0.220 15.80 -26.6 +22.5 6 200 0.080 5.70 0.195 14.00 -55.5 +22.5 7 270 0.125 9.00 0.200 14.40 -30.6 +11.6 8 300 0.145 10.40 0.100 7.20 -19.4 -44.2 9 400 0.160 11.50 0.110 7.92 -11.1 -38.6 10 800 - - 0.010 0.70 - -94.5 x 1A = slowly cooled coal xx AS = quenched coal xxx Change in capacity compared to the capacity of the original coal, experiment no. 1 "Increase in capacity compared to the original product capacity, experiment no. 1.

Table 5 shows that activation in the range 160-270 ° C, and subsequent quenching result in an increase in the chemical sorption capacity compared to the original product, experiment no. 1. Activation at 300 ° C and above it has negative effects. This also applies to slow cooling.

If you compare with example 3, you can see that the physical Sorption and chemisorption can be increased significantly through activation the coal in the temperature range 160-300 ° C and subsequent quenching, i.e. *, a single activation process produces two positive sorption effects at the same time achieved. This result is surprising because of physical sorption and chemical sorption are essentially different processes. Achieved in contrast to selective effects you get a combination of properties of coal, resulting in an accumulation of different Gas types with different sorption mechanisms means.

Example 5 This example shows the improvement of the physical Sorption (chloropicrin) of Cu-impregnated activated carbon of mineral origin shown. The Impregnieru @ consists mainly of mono- and divalent copper oxides and / or Hydroxides As there is no chromium, the impregnation is ineffective with regard to chemical sorption (cyanogen chloride). It is typical old (aged) coal, which had been installed in ventilation systems (air raid shelters) 12 years ago.

The coal contains moisture and has a poor sorption capacity on.

Table 6 shows capacity improvements as a result of activation.

Table 6 Capacity LA x AS xx change xxx Attempt activation Capacity Capacity LA AS No. temperature ° C min / ml mg / ml min / ml mg / ml%% 1 - 0.33 23.7 0.33 23.7 - - 2 80 0.44 31.7 0.42 30.2 +29.5 +27.4 3 130 0.34 24.5 0.47 33.9 + 3.3 +43.1 4 160 0.37 26.7 0.52 37.5 +12.6 +58.2 5 200 0.47 33.9 0.54 39.0 +43.1 +64.5 6 250 0.32 23.0 0.42 30.2 # 2.9 +27.4 x LA = slowly cooled coal xx AS = quenched coal xxx change in capacity compared to the capacity of the original coal, test no. 1 The test conditions are the same as in example 1. The table shows that activation and subsequent quenching give the highest capacity values.

It shows that old (used) coal will be improved can. The capacity values are below those achieved with ASC coal became.

This is due to the much higher physical sorption capacity the ASC coal compared to the mineral coal mentioned.

Example 6 This example is increasing the physical Sorption capacity of non-impregnated coal shown as a result of the controlled Heating in the temperature range below 3000C and the quenching process in one. concentric tube surrounded by liquid nitrogen. A plant for controlled Activation and quenching is shown schematically in FIG. 1. The plant exists from a vertically mounted tube furnace A with a diameter of 10 cm and a 100 cm long heating zone B. The furnace is connected to a cooling unit C. This consists of a concentric tube D, which is in direct connection with the furnace The connection between the furnace and the cooling pipe D can be made with the aid of a valve V1 are interrupted. The cooling pipe has an outer (E) and an inner (F) Surrounding volume, which is filled with cryogenic liquid, e.g. liquid nitrogen is. The cryogenic liquid is passed through the valve V> and the Offnur.g G is introduced into the outer container and passes through the openings H1> Hin the inner container F. Nitrogen gas evaporates through the openings I1, I2 (diameter 5cm) from the inner container to the gas volume in the outer container (E). From here flows the nitrogen gas through the opening K into the atmosphere or to a gas liquefaction plant. When activating coal granulate, this is transferred to the with the valve V1 closed Tube furnace fed in via valve V6. Inert gas e.g. nitrogen is supplied with the help of the pump P is brought into circulation again through the granulate and via the valves V and V1. The moisture in the coal is extracted with the gas and at room temperature or below it by means of another sorbent (in container L). The dry one Gas is returned via Pump-P.

The valve V1 is opened for quenching. The coal arrives by means of Gravity in the concentric pipe D1 where the heat transfer momentarily and radiate takes place from the center of the carbon layer to the pipe walls. From there it will the heat is carried on by evaporation of the liquid nitrogen. Normally Coal has very low heat conduction properties, so that the heat transfer in the axial direction is minimal. The temperature difference in the direction of the axis is also almost zero.

Before the granulate gets from the furnace to the cooling tube D, it is filled with inert gas flushed through valve V6. The granules are kept in the cooling tube until they reach the lowest possible temperature has reached, i.e. up to approximately the boiling point of the cryogenic cooling liquid. The granulate enters the container by removing a movable base N. M under the cooling pipe. This operation is carried out by opening the container M from level Q to level R. The granulate is placed in the container M (the can also be heated) until it has reached room temperature.

8 L non-impregnated carbon granulate of the Sutcliffe Speakman 607 type were activated and quenched as described above. The coal was at 2000C heated and flushed with nitrogen gas at this temperature for 24 hours before she was scared off. Liquid nitrogen was used as the cooling liquid.

150 ml of the activated carbon was tested for its chloropicrin capacity. The test conditions were the same as in Example 1 except for the volume and the bed height (5 cm). The breakthrough time was 76 minutes, a capacity of 76 mg / ml charcoal accordingly. The original unactivated coal had a capacity of 68 mg / ml charcoal. The increase in capacity is therefore 11.7%.

Example 7 Different amounts of coal of the same type were as in example 6, activated and quenched at different temperatures. the Capacity measurements were made in the same way as in Example 6.

In one experiment (experiment # 6) the carbon was activated and slow cooled by being fed into the cooling tube after heating in the tubes. This was surrounded by an atmosphere at room temperature. While it was cooling down flushed the coal with nitrogen gas.

The activation time was 24 hours in all cases, and the activation atmosphere consisted of nitrogen. In Table 7 are the results of the capacitance measurements as well the result of Example 6 is given.

Table 7 Attempt Activation Volume Activation Cooling Through Capacity Capacity x -d. Carbonization rate also change temp-experienced time erature No. ° C 1 ° C / min. min. mg / ml% 1 - - - @@ 68.0 68.0 - 2 200 2.0 AS 29.3xxxx 73.5 73.5 3 200 4.0 AS 35.0Xx 74.5 74.5 9.5 4 | 200 | 8.0 | AS | 38.3xxxxx 76.0 76.0 11.7 5 160 2.0 AS 40.0xxxxxx | 86, o 86, o 26.5 6 160 | 2.0 | LA | 8,4xxx | 71.0 | 4.4 7 160 0.2 AS 800xxx 15.0 30.0 -71.0 8 286 0.2 AS - 79.0 79, o 16.1 9 349 0.2 AS - 55.0 55.0 -19.2 x Change in capacity compared to the capacity of the original coal, test no.l xx The cooling rate is taken from the temperature range +40 - -400C of the temperature curve xxx The cooling rate is taken from the temperature range +152 - + 930C of the temperature curve.

xxxx Directly quenched in liquid nitrogen LA = slowly cooled Coal AS = quenched coal Table 7 shows that the capacity increase from the activation temperature and the cooling rate is dependent. The quenching activation in pipes results in the greatest increase in capacity here at 1600C. Activation followed by cooling in direct contact with liquid Uitrogen, gives a negative effect.

Example 8 In these experiments the importance of the cooling rate for increasing the capacity of non-impregnated coal of the same make and type as demonstrated in Example 7. 2 L of each sample was used for these experiments. Nitrogen and helium were used as the activation and cooling atmosphere. For The apparatus described in Example 6 was used for the experiments.

Coal granules with a larger grain size (particle diameter) have a higher thermal resistance than granules with a smaller particle diameter. Bigger ones Granules are therefore cooled more slowly. The total heat transfer coefficient (kcal / m . hr) in the cooling tube depends on the quality of the carbon granulate and on the Atmosphere in the intergranular volume and in the pore volume of the granulate.

Table 8 Attempt Activation Cooling Active Cooling Through Capacity Capacity Numbering fractions increase atmo- atmo- temp- ratex time Sphaere Sphaereeratur ° C ° C / min min. Min. Mg / ml% 1 - - - - 68.0 68.0 - 2 N2 N2 200 29> 3 73.5 73.5 8.0 3 lle Re 200 11); 82.0 82.0 20.6 x The cooling rate is calculated within the temperature range +40 - -40 ° C of the temperature curve.

xx The increase in capacity compared to the capacity of the original coal, Experiment No. 1 The activated granules were based on the chloropicrin capacity tested These results were tested together with the results from Example 7, Experiment 1 and 2 shown.

Table 8 shows that there is a significantly higher cooling rate can be achieved by increasing the heat transfer coefficient with the help of a gas (He) with a higher thermal conductivity than Nitrogen, which leads to an increase in capacity leads.

Example 9 75 ml samples of non-impregnated mineral carbon (blended briquetted coals) of the type Sutcliffe Speakman 206A were for 3 hours in a Activated quartz tube with an internal diameter of 18 mm. The pipe with the coal was on then quenched in liquid nitrogen or slowly to room temperature cooled down. The samples were flushed with nitrogen gas during the entire process, Approx. 0.5 l / min.

The granules were then up under the following conditions its chloropicrin capacity tested .: Granules: 1.68-0.50mm, 10-30 BSS mesh bed volume : 8 ml bed height: 4.5 cm 2 bed area: 2.35 cm air supply: 2.35 1 / min.

Linear speed: 10 m / min.

Picrin concentration: 5 mg / l air Picrin supply: 8.75 mg / min.

Relative humidity: 0% Table 9 shows the results along with the capacity of the original product. The original capacity is very low compared to the chloropicrin capacity of ASC carbon (example 1 and 3) namely 105 mg / ml.

Table 9 Attempt activation activation cooling through capacity capacity; eration rate x fracture increase temperature procedure | | Time No. C ° C / min min mg / ml 1 | - | - | | 19 | 20.7 2 108 AS 114 43 46.8 126.0 3 108 LA 12 32 35.0 69> 0 4 207 AS 118 54 59.0 185.0 5 207 LA 21 27 29.5 42.5 x The cooling rate measured in the temperature range 108 - 500C or 207 - 500C of the temperature curve.

xx capacity increase compared to the capacity of the original coal, Trial No. 1 LA. = slowly cooled coal AS = quenched coal the end the table shows that coal has a low physical sorption capacity through activation and quenching results in a significant capacity improvement.

Example 10 Sutcliffe Speakman 607 carbon granules were used in 1600C activated as described in Example 6. Thereafter, the granules were with regard to the benzene capacity checked. A dry stream of air saturated with benzene vapor (0.27 L / min.) Corresponding to 4.23% by volume at 5.7 ° C was through a filter with a Volume of 7 ml, a bed height of 6 cm, a bed area of 1.16 cm at 2.34 m / min. linear speed and 25 ° C filter temperature. This matches with a benzene dosage of 42.0 mg / min. The benzene uptake was determined by weighing the Granulate checked before and after breakthrough. The breakthrough of Benezn was measured with a GOW MAC thermal conductivity analytical cell measured and is in this. Example defined at the time when the Benzene concentration in the air when it exits the filter reaches the same value has like the benzene concentration of the supply air. At this point the trials were over canceled and the filter mass was weighed. Attempts were made with activated, quenched coal (AS) and slowly cooled coal (L4). The results are shown in Table 10. The capacity is in mg benzene / g Coal indicated.

Table 10 Attempt Activation Cooling Weight Capacity Capacity temperature procedure d. Coal increase ex filters No. oc g mg / g 1 - - 3.3 318 - 2 160 LA 3.3 350 +10.0 3 160 AS 3.3 360 +13.2 x increase in capacity compared to the capacity of the original charcoal, experiment no. 1 LA = slowly cooled charcoal AS = quenched charcoal Example 11 Sutcliffe Speakman 206A activated charcoal was activated and cooled as described in example 9. The coal was examined for its benzene capacity at 250C. The other test conditions are given in Example 10, with the exception of the bed volume which was 10 ml.

0 4.9 g of the coal type mentioned was activated at 207 C and quenched. The benzene uptake was 0.835 g, corresponding to 0.204 g benzene / g carbon or 20.4 % By weight benzene per gram of coal.

The original material had a benzene capacity equivalent to 0.128 g benzene / g carbon with a standard deviation of + 4.3%. The capacity increase in Compared to the original product, this is 0.076 g-benzene / g coal or 59.5%.

In Table 11 is the capacity measurement of the original coal and the Charcoal activated and quenched (AS) or slowly cooled is listed.

Table 11 Attempt Activation Activation Weight Sorbiefte Capacity Capacity No- ungs of the coal benzene increase temperature procedure ggg Benzene /. g coal 1 | | | | | 0.128xx | 0 2 108 AS 4.43 o, 836 0.189 47.5 3 108 LA 4.57 0.667 0.146 14.0 4 207 AS 4.24 0.877 0.207 61.6 5 207 LA | 4.44 0.711 0.160 25.0 6 500 AS 4.39 0.736 0.168 31.2 x increase in capacity compared to the capacity of the original coal xx mean value of 3 measurements LA = slowly cooled coal AS = quenched coal The cooling was carried out in a cooling liquid consisting of solid carbonic acid (CO2) and carbon trachloride. The temperature measured in the coolant was -66 ° C. The activated carbon was tested for its chloropicrin capacity.

The test conditions were the same as in Example 3 .: There was a Breakthrough time of 69 min. For 75 ml carbon filter reaches 0.92 min./ml.

A compilation of the test results of charcoal after activation at different cooling rates is shown in Table 12.

Table 12 attempt activation temperature cooling ratexx capacity capacity -d. Cooling | change x procedure mediums 0 No. ° C ° C / min min / ml mg / ml% 1 - - - 0.70 105 0 2 AS -i96 250 1.12 168 +60.0 3 AS - 66 90 0.92 138 +31.4 4 | LA | + 20 | 18 | 0.62 | 93 | -11.4 xx temperature range: x change in capacity compared to the capacity of the original coal, experiment no.

LA = slowly cooled coal AS = quenched coal example 13 This example deals with the adsorption of nitrogen gas by ASC charcoal, which / has been activated and cooled down several times. The coal was of the same type as in example 1. The adsorption mechanism corresponds to the typical physical one Sorption including capillary condensation. The activation happened through Heat 75 ml of carbon to Igo C in a quartz glass tube for 3 hours Coal was quenched in liquid nitrogen (approx. 15 min.) And brought to room temperature warmed up. 5 g of the sample were saved for sorption measurements.

The remaining charcoal, approx. 72 ml, became up again over the course of 3 hours Heated to 160 C and then quenched. This activation / cooling cycle was repeated 4 times repeated.

To measure the adsorption of nitrogen gas by coal (adsorption isotherms) an apparatus was used which is normally used to measure the sorption isotherms to measure the nitrogen. Such an apparatus is in the publication (S.J. Gregg, K. Sing, Absorption, Surface Area and Porosity, p. 314-316, 1967) been. The principle is that a known amount of nitrogen gas is in equilibrium is brought with a known amount of adsorbent. When sorption equilibrium is used read the equilibrium pressure. The volume and temperature of the gas phase is known. With the help of the gas law pv = nRT, the amount of nitrogen in the gas phase is determined calculated, and this is deducted from the originally added amount of nitrogen. The door reference means adsorbed amount. When the amount of gas increases, it increases also the equilibrium pressure and the amount of gas adsorbed.

The amount of gas adsorbed is given as cm3 of nitrogen gas per gram of coal. The nitrogen gas volume is defined at 0 ° C and 760 mm Hg.

55.6 mg charcoal that had been activated and quenched 3 times, like evacuated for 3 hours at 25 C to a pressure of 2 10-4 mm Hg. Samples were then cooled to -1960C and topped up with nitrogen gas until an equilibrium pressure was reached of 490 mm Hg was reached.

P 495 This corresponds to a relative equilibrium pressure P @ = kW = O, 65. P = measured vapor pressure of the liquid nitrogen at the existing atmospheric pressure. The amount of nitrogen adsorbed was 278 cm @ / g carbon. The original product like! at the at the same relative equilibrium pressure, a nitrogen uptake of 255 cm / g coal on. The activated coal samples have thus experienced a capacity increase of 13 cm nitrogen / g coal, corresponding to 9.0%.

Example 14 The following examples focus on increasing sorption the coal pointed out which has been activated and quenched up to 4 times, like described in Example 13. The samples are of the same type of coal as in the examples 1 and 13. The samples were pretreated (evacuated) in the same way and measured as described in Example 13. The amount of nitrogen adsorbed was measured at different equilibrium pressures.

The results of the measurements were shown in Table 13.

The table shows the relative equilibrium pressure P / P0. The table shows that by increasing the number of activation / quenching processes an increase in sorption is achieved. The increase is at low relative pressure the biggest.

P At a relative pressure of P0 = 0.98 it is generally assumed that that the adsorbed nitrogen is in a condensed state. In practice it means that the total pore volume is filled with liquid nitrogen. The adsorbed Gas volume can be converted into liquid nitrogen volume by multiplying will.

The percentage of the capacity increase achieved is therefore pressing also a corresponding increase in the total pore volume.

Table 13 Attempt Number Relative Adsorbed Capacity Note No deterrent balance increase procedure pressure quantity N2 P cm³ / g kull Po 1 0 0.20 219 0 original product 2 1 0.20 227 + 3.6 3 2 0.20 | 241 +10.0 4 3 0.20 241 +10.0 5 4 | 0.20 253 +15.5 6 | 0 | 0.40 | 244 | 0 | Original- product 7 | 1 | 0.40 | 251 | 2.8 8 2 0.40 264 8.0 9 3 0.40 267 9.1 | 10 4 0.40 276 12.7 11 0 0.65 255 0 original product 12 1 0.65 257 0.7 13 2 0.65 275 7.8 14 3 0.65 278 9.0 15 lt - 0.65 280 9.8 16 | 0 | 0.98 | 293 | 0 | Original- product 17 1 o, 98 308 5.1 | 18 2 0.98 315 7.4 19 3 0.98 319 8.8 20 4 - 0.98 325 10.9 Example 15 This example demonstrates the sorption effect as a result of the activation and the repeated quenching process in liquid nitrogen with regard to the impregnated ASC activated carbon of the same type as mentioned in Example 3. Chloropicrin was used as the sorbing gas. 1.75 l / min. Air containing 5 mg of chloropicrin / l was passed through a filter made of said activated carbon.

This corresponds to a picrine dosage of 8.75 mg / min. Samples had been activated for 3 hours at 170 C in a nitrogen atmosphere and then Quenched in pipes surrounded by liquid nitrogen. The filter temperature was 250C. The filter area measured 2.40 cm. It took 35 minutes for the breakthrough of the gas what a. Capacity of 76.5 mg / ml charcoal. The unactivated original coals had a capacity that was 61.2 mg / ml charcoal.

The capacity increase is therefore 25.0. The results after repeated Activations are shown in Table 14. Table 14 shows that a increased number of activation and quenching processes an increase in the sorption capacity causes.

Table 14 Attempt number of breakthrough capacity capacity Activations time increase x No. Min. Mg / ml charcoal 1 original 61.2 '0 2 1 35 76.5 25.0 3 2 36 78.6 28.4 4 3 37 81.0 32.3 5 | 4 | 39 | 85.0 | 38.8 x Increase in capacity compared to the capacity of the original coal, experiment no. 1 Example 16 This example documents the increase in the chemisorption of SO2 by K2C03-impregnated coal of the type "Dräger E 900".

11.0 g charcoal, which is activated for 3 hours in a nitrogen atmosphere and then quenched in a quartz tube surrounded by liquid nitrogen was checked for its SO2 capacity.

3.34 l / min. an SO2-air mixture that contained 0.39% by volume of SO passed through a filter of activated carbon. The filter mass had a volume of 22 ml and bed diameter 2.2 cm. The linear gas velocity through the filter was 0.146 m / sec, and the filter temperature was 25 C.

The breakthrough of SO2 was at a concentration of 0.014 vol.% SO registered in delta effluent gas. A GOW MAC thermal conduction detector was used for this purpose used.

The charcoal had adsorbed 240 mg SO at the breakthrough. Corresponding an SO2 capacity of 0.0218 g SO2 / g coal.

The original coal had a capacity corresponding to 0.0199 g SO2 / g coal.

The capacity increase is thus 9.6%.

Example 17 This example demonstrates the increase in SO2 capacity of inpregnated charcoal that activates at different temperatures (up to 290 C) and has been quenched in liquid nitrogen (ES).

The coals are of the same type as described in Example 16 as well the experimental conditions.

Table 15 Attempt Activation Activation Capacity Capacity ungs- mgSO2 / g charcoal temperature procedure% ° C 1 - 19.9 2 115 AS 21.8 | + 9.6 3 115 LA 20.2 + 1.5 4 150 AS 22.3 +12.1 5 150 LA 19.3-3.0 x 6 265 AS 41.3 +107.5 7x | 265 LA 32.8 +64.5 8 300 AS 26.8 +34.4 Because of the intensive course of the reaction in the air stream, the SO uptake was carried out in a nitrogen atmosphere.

Example 18 Sutcliffe Speakman 607 carbon granules were like Described in Example 10 heated to 160 C and then quenched. Of the granules was tested with regard to the benzene capacity at 90 C. One with benzene vapor (4.23 Vol%) saturated air flow (265 cm / min) was passed through a filter with a volume of 10 cm3. The other dimensions of the filter were the same as described in Example 10, with the exception of the height. The benzene intake was controlled by weighing the gray matter before and after the gasoline breakthrough. The breakthrough is defined at the point in time in which the benzene concentration in the outflowing air had reached 0.11 vol%. A thermal conduction detector (GOW MAC) was used for this purpose.

The results are shown in Table 16.

Table 16 Attempt Activation Weight Sorbed Capacity Capacity -d. Coal benzene increase No. mg benzene procedure g amount% mg 1 original 4.07 504 123.8 0 2 LA 4.10 660 161.0 +30.1 3 AS 4.10 762 186.0 +50.2 x change in capacity compared to the capacity of the original coal, experiment no. 1 LA = = slowly cooled coal AS = quenched coal

Claims (6)

PATENT CLAIMS 1. Method for improving sorption capacity of activated carbon by heating and subsequent quenching by means of a cooling medium, characterized in that the coal is first in an inert atmosphere except for one Temperature in the area 50-300 C and then heated by means of heat dissipation through a Partition wall on a quantity of medium on the other side of the wall except for one Temperature of less than -66 C is quenched. 2. The method according to claim 1, characterized in that the Quenching takes place in an inert atmosphere. 3. The method according to claim 1, characterized in that the partition is equipped so that the quenching at a cooling rate of 90-400 C / min runs down to 0 C. 4. The method according to claim 1, characterized in that the heat dissipation through the dividing wall with grooves by means of condensation of incoming inert Gas is combined due to the Joule-Thompson effect. 5. Device for improving the sorption capacity of activated carbon by heating and subsequent quenching by means of a cooling medium, when executed of the method according to claims 1-4, characterized in; that a vertically mounted Tube furnace for heating the activated carbon in an inert atmosphere above a cooling chamber is arranged, which is separated from a cooling medium container by a partition is, wherein the tube furnace with the cooling chamber by a closable pipe connection for transferring the heated activated carbon to the cooling chamber by means of gravity when opening the pipe connection is connected. 6. Apparatus according to claim 5, characterized in that the cooling chamber ring-shaped and both inside and outside the ring shape of the cooling medium container is separated by the partition. L e r s e i t e