Activated carbon



LU Free format text: Für die neue Golf-Generation hat der Volkswagenkonzern unter. The large charcoal beds adsorb these gases and retain them while they rapidly decay to non-radioactive solid species. Nach der Verwiegung und Dosierung aller Komponenten des Rezeptes fördert die Bandwaage alle Zutaten automatisch bis zu den Mehlbehälterwaagen oder in eigene bnahmezielstellen. As a measurement of the air mass flow and the drive torque for the rotary blowers can be tapped or a corresponding jam door or similar, from the motor vehicle known for Ansaugluftmessung air flow meter can be used.

KEY FEATURES


Passing an organically impure vodka through an activated carbon filter at the proper flow rate will result in vodka with an identical alcohol content and significantly increased organic purity, as judged by odor and taste. Research is being done testing various activated carbons' ability to store natural gas [2] [1] and hydrogen gas. The gas is attracted to the carbon material via Van der Waals forces. Some carbons have been able to achieve bonding energies of 5—10 kJ per mol.

The gas may then be desorbed when subjected to higher temperatures and either combusted to do work or in the case of hydrogen gas extracted for use in a hydrogen fuel cell. Gas storage in activated carbons is an appealing gas storage method because the gas can be stored in a low pressure, low mass, low volume environment that would be much more feasible than bulky on-board pressure tanks in vehicles. The United States Department of Energy has specified certain goals to be achieved in the area of research and development of nano-porous carbon materials.

All of the goals are yet to be satisfied but numerous institutions, including the ALL-CRAFT program, [1] [2] [12] are continuing to conduct work in this promising field. Filters with activated carbon are usually used in compressed air and gas purification to remove oil vapors, odor, and other hydrocarbons from the air. The most common designs use a 1-stage or 2 stage filtration principle in which activated carbon is embedded inside the filter media. Activated carbon filters are used to retain radioactive gases within the air vacuumed from a nuclear boiling water reactor turbine condenser.

The large charcoal beds adsorb these gases and retain them while they rapidly decay to non-radioactive solid species. The solids are trapped in the charcoal particles, while the filtered air passes through. Activated carbon is commonly used on the laboratory scale to purify solutions of organic molecules containing unwanted colored organic impurities.

Filtration over activated carbon is used in large scale fine chemical and pharmaceutical processes for the same purpose. The carbon is either mixed with the solution then filtered off or immobilized in a filter. Activated carbon, often infused with sulfur [13] or iodine, is widely used to trap mercury emissions from coal-fired power stations , medical incinerators , and from natural gas at the wellhead.

Since it is often not recycled, the mercury-laden activated carbon presents a disposal dilemma. The problem of disposal of mercury-laden activated carbon is not unique to the United States. In the Netherlands, this mercury is largely recovered [ citation needed ] and the activated carbon is disposed of by complete burning. Activated carbon is carbon produced from carbonaceous source materials such as bamboo, coconut husk, willow peat , wood , coir , lignite , coal , and petroleum pitch.

It can be produced by one of the following processes:. Activated carbons are complex products which are difficult to classify on the basis of their behaviour, surface characteristics and other fundamental criteria.

However, some broad classification is made for general purpose based on their size, preparation methods, and industrial applications. Normally, activated carbons R 1 are made in particulate form as powders or fine granules less than 1. Thus they present a large surface to volume ratio with a small diffusion distance. PAC material is finer material.

The ASTM classifies particles passing through an mesh sieve 0. It is not common to use PAC in a dedicated vessel, due to the high head loss that would occur. Instead, PAC is generally added directly to other process units, such as raw water intakes, rapid mix basins, clarifiers, and gravity filters.

Granular activated carbon GAC has a relatively larger particle size compared to powdered activated carbon and consequently, presents a smaller external surface. Diffusion of the adsorbate is thus an important factor. These carbons are suitable for adsorption of gases and vapors, because they diffuse rapidly.

Granulated carbons are used for water treatment , deodorization and separation of components of flow system and is also used in rapid mix basins. GAC can be either in granular or extruded form. Standard Mesh Size No. AWWA B uses the mesh sieve 0. Extruded activated carbon EAC combines powdered activated carbon with a binder, which are fused together and extruded into a cylindrical shaped activated carbon block with diameters from 0.

These are mainly used for gas phase applications because of their low pressure drop, high mechanical strength and low dust content. Bead activated carbon BAC is made from petroleum pitch and supplied in diameters from approximately 0. Similar to EAC, it is also noted for its low pressure drop, high mechanical strength and low dust content, but with a smaller grain size.

Its spherical shape makes it preferred for fluidized bed applications such as water filtration. Porous carbons containing several types of inorganic impregnate such as iodine , silver , cations such as Al, Mn, Zn, Fe, Li, Ca have also been prepared for specific application in air pollution control especially in museums and galleries. Due to its antimicrobial and antiseptic properties, silver loaded activated carbon is used as an adsorbent for purification of domestic water.

Drinking water can be obtained from natural water by treating the natural water with a mixture of activated carbon and Al OH 3 , a flocculating agent. Impregnated carbons are also used for the adsorption of Hydrogen Sulfide H 2 S and thiols. This is a process by which a porous carbon can be coated with a biocompatible polymer to give a smooth and permeable coat without blocking the pores.

The resulting carbon is useful for hemoperfusion. Hemoperfusion is a treatment technique in which large volumes of the patient's blood are passed over an adsorbent substance in order to remove toxic substances from the blood. There is a technology of processing technical rayon fiber into activated carbon cloth for carbon filtering. Adsorption capacity of activated cloth is greater than that of activated charcoal BET theory surface area: Thanks to the different forms of activated material, it can be used in a wide range of applications supercapacitors , odour-absorbers, CBRN defense industry etc.

Under an electron microscope , the high surface-area structures of activated carbon are revealed. Individual particles are intensely convoluted and display various kinds of porosity ; there may be many areas where flat surfaces of graphite -like material run parallel to each other, [2] separated by only a few nanometers or so. These micropores provide superb conditions for adsorption to occur, since adsorbing material can interact with many surfaces simultaneously.

James Dewar , the scientist after whom the Dewar vacuum flask is named, spent much time studying activated carbon and published a paper regarding its adsorption capacity with regard to gases. Physically, activated carbon binds materials by van der Waals force or London dispersion force. Activated carbon does not bind well to certain chemicals, including alcohols , diols , strong acids and bases , metals and most inorganics , such as lithium , sodium , iron , lead , arsenic , fluorine , and boric acid.

Activated carbon adsorbs iodine very well. Carbon monoxide is not well adsorbed by activated carbon. This should be of particular concern to those using the material in filters for respirators, fume hoods or other gas control systems as the gas is undetectable to the human senses, toxic to metabolism and neurotoxic. Substantial lists of the common industrial and agricultural gases adsorbed by activated carbon can be found online.

Activated carbon can be used as a substrate for the application of various chemicals to improve the adsorptive capacity for some inorganic and problematic organic compounds such as hydrogen sulfide H 2 S , ammonia NH 3 , formaldehyde HCOH , mercury Hg and radioactive iodine I.

This property is known as chemisorption. Many carbons preferentially adsorb small molecules. Iodine number is the most fundamental parameter used to characterize activated carbon performance. It is the standard measure for liquid-phase applications. Iodine number is defined as the milligrams of iodine adsorbed by one gram of carbon when the iodine concentration in the residual filtrate is at a concentration of 0.

Basically, iodine number is a measure of the iodine adsorbed in the pores and, as such, is an indication of the pore volume available in the activated carbon of interest. Typically, water-treatment carbons have iodine numbers ranging from to Frequently, this parameter is used to determine the degree of exhaustion of a carbon in use. However, this practice should be viewed with caution, as chemical interactions with the adsorbate may affect the iodine uptake, giving false results.

Thus, the use of iodine number as a measure of the degree of exhaustion of a carbon bed can only be recommended if it has been shown to be free of chemical interactions with adsorbates and if an experimental correlation between iodine number and the degree of exhaustion has been determined for the particular application. Some carbons are more adept at adsorbing large molecules. A high molasses number indicates a high adsorption of big molecules range 95— Caramel dp decolorizing performance is similar to molasses number.

The European molasses number range — is inversely related to the North American molasses number. Molasses Number is a measure of the degree of decolorization of a standard molasses solution that has been diluted and standardized against standardized activated carbon. Due to the size of color bodies, the molasses number represents the potential pore volume available for larger adsorbing species. As all of the pore volume may not be available for adsorption in a particular waste water application, and as some of the adsorbate may enter smaller pores, it is not a good measure of the worth of a particular activated carbon for a specific application.

Frequently, this parameter is useful in evaluating a series of active carbons for their rates of adsorption. Given two active carbons with similar pore volumes for adsorption, the one having the higher molasses number will usually have larger feeder pores resulting in more efficient transfer of adsorbate into the adsorption space.

Tannins are a mixture of large and medium size molecules. Carbons with a combination of macropores and mesopores adsorb tannins. The ability of a carbon to adsorb tannins is reported in parts per million concentration range ppm— ppm. Some carbons are evaluated based on the dechlorination half-life length, which measures the chlorine-removal efficiency of activated carbon. The dechlorination half-value length is the depth of carbon required to reduce the chlorine level of a flowing stream from 5 ppm to 3.

Proportional to the mass flow of the respective Coriolis force is detected as the reaction torque on the load cells 9, 19 and 29 and passed on to the evaluation unit as a measurement signals M1, M3 and M4. The same applies for the mass flow M5 of the component which is added at the feed device 22, wherein the differential torque M5 determined from the measured at the measuring device 23 total mass flow corresponding to the measured value M4 and the measuring device 1 measured value is formed M1 here.

The arrangement of three measuring devices described here can be extended to a variety so that any number of components can be measured for dosages. Jedoch können die beiden vor- bzw. In contrast to the measuring device in Fig. Die übrigen Bezugszeichen für funktionsgleiche Teile entsprechen denen aus Fig. The remaining reference numerals for functionally equivalent parts correspond to those of Fig. As can be seen, the drive motor is rotatably mounted in an intermediate housing 30 8, so that the housing rests upon the occurrence of the Coriolis force in the measuring mode to the load cell 9, and thus the to each flowing through mass flow proportional detected braking torque.

Das Zwischengehäuse 30 ist über Rippen 31 drehfest mit dem Gehäuse 12 verbunden. From the intermediate casing 30, a pipe 32 leads out, which serves the exhaust duct of the drive motor 8, and can receive the power cable and the data lines of the load cell. The measuring wheel 4 up to reaching the feed-7 radial vanes 5 is attached via a tie rod 33 on the motor shaft of the drive motor. The measuring wheel 4 is formed in the flow swept so that an aerodynamically favorable transmission of the bulk material and the air flow results in pneumatic conveying.

The arrow angles of the measuring wheel 4 is chosen so that, depending on the density of the conveyed material it is conveyed without touching the exterior and interior surfaces to the outside. To this end, the the feed-7 facing ends of the guide vanes 5 are bent in the circumferential direction or bent, so that the supplied Fördergutpartikeln a radial acceleration is issued immediately upon entry into the measuring wheel 4 and shock-free as possible to accept this the angular speed of the measuring wheel.

Also, the ribs 31 may be formed as a rectifier, so that a low-friction flow through the measuring device 1 is obtained. Also, the pipe 32 is in this case provided in the flow or oval with a drop-shaped cross-section. By the arrow-shaped design of the measuring wheel 4, also results in a compact design, so that the measuring device is easy to install, especially in pneumatic conveying systems.

Dies wird beispielhaft an den nachfolgenden Figuren gezeigt. This is exemplified in the following figures. Als dazwischengeschaltete Beschickungsvorrichtung 2 ist eine Durchblasschleuse 40 an der Unterseite eines Zuführtrichters 10, z. As intermediary charging device 2 is a blow-through 40 at the bottom of the feed hopper 10, z. Die Durchblasschleuse 40 weist einen Dosierrotor 42 auf, der in einem geschlossenen Gehäuse 41 um eine Antriebswelle 44 umläuft. The mass M3 of the conveying air in the manner described above is detected by measuring the forces acting on the feed wheel 14 reaction torque M3 that is detected at the load cell On the upper measuring apparatus 1 of the total mass flow of the M1 withdrawn from the feed hopper 10 conveyed M2 is detected together with the incoming air at the inlet 13 transport gas M3.

By forming the difference between the detected in the load cells 9 and 19 moments M1 minus M3 is proportional to the mass of the supplied material to be conveyed differential torque M2 formed.

To a trouble-free flow of the measuring arrangement are in each case before and after the feed wheel 14 and the measuring wheel 4 rectifiers 47 and 48 are provided, so that an almost swirl-free flow is achieved. It should be noted that the feed wheel 14 in this case not only the measurement of the Coriolis force acts, but at the same time the generation of the air flow for the promotion in the vertical direction is used.

Die Förder- oder Gebläsewirkung des Förderrads 14 reicht für geringere Förderhöhen und leichtes Fördergut dabei vollständig aus. The conveyor or fan effect of the feed wheel 14 is sufficient for smaller heads and light conveyed it completely.

Ergänzend hierzu kann auch am Lufteintritt 13 ein zusätzliches Gebläse vorgesehen sein. In addition to this, also at the air inlet 13, an additional fan may be provided. The fluidized bed sluice 50 essentially consists of a hermetically closed pressure vessel 51, 52 compressed air for fluidization and loosening of the conveyed goods located in the pressure vessel is introduced into the from the bottom.

The mass M3 of the introduced compressed air is in this case detected by the measuring device. The conveyed material passes from the pressure vessel 51 via a feed line 53 to the measuring device 1, which thus in turn the overall mass flow M1 from the conveyed material mass flow M2 and the conveyor fluid mass flow M3 is detected here the compressed air. Here, the measuring wheel 4 of the measuring device 1 can be used advantageously in addition to the compressed air injection at the bottom 52 to the suction of the transported material.

For refilling the pressure vessel 51 a bulk hopper 54 is provided, whose Entleermenge is controlled via a rotary valve 55 so that the bed height of the conveyed material in the pressure vessel 51 remains approximately constant.

The rotary valve 55 is in this case designed so that the best possible sealing against air leakage is achieved, so that the influent into the pressure vessel 51 air M3 and the pressure vessel 51 leaving the total mass flow M1 is to be determined accurately from being conveyed and the conveying fluid without air leakage. The metering roller 60 has at its outer periphery recesses 61 that run according to the driving of the conveyed material from the feed hopper 10 down and there will be transported from the entering through the measuring device 3 conveying air to the right of the measuring device.

There is proportional to the mass flow of the conveying air reaction torque M3 that has been detected by the load cell 19 is subtracted, so that the mass flow of the conveyed material M2 is obtained without the error moment of the conveying fluid.

With a suction nozzle 71, the conveyed shown in dotted lines is extracted from a vessel body, 71 significant amounts of air are sucked in at the suction nozzle. The conveyed conveyor air mixture first passes through the measuring device 1, which thus determines the overall mass flow M1 of the conveyed with the conveying fluid.

Das Fördergut wird in einem Zyklonabscheider 72 weitgehend aus dem angesaugten Fördergut-Förderfluid-Gemisch abgetrennt und über eine Zellenradschleuse 73 einem Silo 74 zugeführt.

The material is largely separated in a cyclone separator 72 from the sucked conveyor conveyed fluid mixture and is fed via a rotary vane 73 a silo 74th Die Zellenradschleuse 73 dient dabei der Abdichtung der gesamten Sauganlage. The rotary valve 73 serves to seal the entire intake system. Vom Zyklonabscheider 72 gelangt das nur noch geringe Mengen Fördergut enthaltende Gemisch in einen Filter 75, wobei wiederum ein hoher Prozentsatz des Fördergutes abgeschieden wird und über eine Zellenradschleuse 76 dem Silo zugeführt wird.

From the cyclone separator 72 which passes only small quantities conveyed containing mixture into a filter 75, again with a high percentage of the transported material is deposited and is supplied via a rotary valve 76 the silo. The conveying air enters the filter 75 via the measuring device 3 to the suction fan 77, which operates the entire suction conveyor 70 substantially.

In the measuring device 3, the mass flow M3 of the conveying air and remaining therein fine dust thus is detected. It is essential here that even fine dust particles that were not separated in the filter 75, but in the mass calculation taking a significant share, are also detected.

Somit gehen nicht abgetrennte Komponenten wie Feinstäube und die Luftmasse nicht als Fehlerquellen in die Massenberechnung für das sich letztendlich im Silo 74 befindliche Fördergut ein. Thus, do not separated components such as fine dust and the air mass is not as sources of error into the mass calculation for himself ultimately located in the silo 74 to be conveyed. Da gerade bei derartigen Saugförderanlagen erhebliche Luftmengen bzw. Since considerable amounts of air or air masses to promote the conveyed material are particularly necessary for such a vacuum conveying systems, thus measurement inaccuracies can be off by several percentages.

Förderräder 4 und 14 von einem einzigen Motor 8 angetrieben werden. It is essential that both measuring and conveying wheels 4 and 14 are driven by a single motor. In this way, the rotational speed of both measuring wheels 4 and 14 for controlling the flow rate can be regulated. This has for example the advantage that when an injector or a siphon, the rise in the amount of gas proportional amount of bulk material can be controlled without an additional control element as a feeding device.

Of importance in this embodiment is further that the torque measurement is carried out outside of the housing 12 and thus outside of the flow path of the conveyed material and the conveying fluid. Dies ist insbesondere bei aggressiven Komponenten von Vorteil. This is particularly aggressive components beneficial. The measuring wheels 4 and 14 are in this case mounted on cantilever arms 80 and 81, which are connected via an intermediate pipe 82nd Letzteres und die Ausleger 80 und 81 nehmen ein Getriebe, vorzugsweise zwei Riementriebe 83 mit einer Zwischenwelle 84 staubdicht auf.

The latter and the arms 80 and 81 take a gear, preferably two belt drives 83 dustproof with an intermediate shaft Die Auslegerarme 80 und 81 ragen hierbei in geschlossene Einbuchtungen 88 des Gehäuses 12, die erstere mit geringem Spiel umgeben.

The cantilever arms 80 and 81 extend in this case in closed indentations 88 of the housing 12, the former is surrounded with a small clearance. In this way, the cantilever arms 80 and 81 rotate slightly as the sole degree of freedom to pivot bearings 89 about the shafts 6 and 17 of the measuring wheels 4 and 14 and thus to pass torque changes. As can be seen from the associated cross-section along the line AA through the boom 81, is achieved a reversal of direction via the intermediate shaft 84, so that the two measuring wheels 4 and 14 rotate in opposite directions.

At the intermediate tube 82 a Parallelogrammlenkergestänge 85 is fastened, which acts upon the provided for measuring torque load cell 9 via a vertical arm 86, as can be seen from the sectional view according to the section line BB. The parallelogram linkage 85 is carried out so that the intermediate tube 82 is statically determined and tied up.

Der Lenker 86 ist zur Abstützung an einem Abstützpunkt 87 an z. The handlebar 86 is a support point for support on 87 at z. Because of the reverse direction of rotation of the measuring wheels 4 and 14, the displacement of the steering linkage 85 and thus the loading of the load cell corresponding section BB see. Proportional yields 9 the difference torque between the measuring devices 1 and 3. This differential torque is in turn proportional to the mass flow of the conveyed material, so that in consideration of the lever length can be ascertained directly at corresponding types calibration of the load cell 9 86, the mass flow of the conveyed material without the error influence of the conveying air.

It is particularly advantageous that the guide bar 85 is considerably less friction than a rolling bearing and also the pivot bearing 89 by the mounting easily respond directly to the shafts 6 and 17 to torque changes.

In the sectional view BB a breakthrough in the cantilever arm 81 and the bulge 88 is also indicated dash-dotted lines, so that thrown off the material to be conveyed can pass here, provided that the belt drive 83 on the outermost boom arm 81 extends and is encapsulated.

In addition, for each measuring apparatus, a separate drive motor 8 or 18 is provided. With this arrangement, the differential torque M1 - M3 will turn on the load cell 9 tapped proportional measured value.

Diese Anordnung eignet sich z. This arrangement is suitable for. As well as for the suction conveyor 70 in Fig. Durch das doppelseitige Parallelogrammgestänge, wie dies insbesondere in der zu Fig. According to the suction conveyor 70 in Fig. Although both measuring devices have the same direction of flow, one of the measuring devices could also promote in the opposite direction, for example by a mirror-image arrangement along the section line CC.

As a measurement of the air mass flow and the drive torque for the rotary blowers can be tapped or a corresponding jam door or similar, from the motor vehicle known for Ansaugluftmessung air flow meter can be used. Similarly, a dynamic pressure measurement for detecting the air feed mass flow M3 may be performed. Anstatt dem Drehkolbengebläse 90 kann natürlich auch, je nach gefordertem Förderdruck, ein Schraubenverdichter oder ein Radialgebläse vorgesehen sein.

Instead of the rotary blower 90 can of course also be provided, depending on the required delivery pressure, a screw compressor or a centrifugal blower. Together with the measured value of the load cell 9 as a direct measure of the mass flow of the conveyed material from the feed hopper 10 together with the conveying air, the difference value of M1 is again - M3 formed, so that the net flow rate M2 of the conveyed material alone, without the error influence of the additional conveying air mass is determined.

Die Turbine 91 eignet sich im Gegensatz zum Hitzdrahtmesser in Fig. The turbine 91 is contrary to the Hitzdrahtmesser in Fig. Das an der Turbine 91 durch den Fluidstrom M3 hervorgerufene Drehmoment wird über deren Welle, die in einem Gleichrichter 92 an der Position 93 gelagert ist, an ein Umkehr-Getriebe 94 geleitet.

There, the torque of the turbine 91 via an intermediate shaft 95 and a reversing wheel is conducted to the shaft 6 of the measuring wheel 96 and possibly 4 stocky. Die Welle 6 ist durch eine Lagerung 98 in einem weiteren Gleichrichter 97 gelagert. The gear case 94 is rotatably mounted on the two shaft ends and is supported on the load cell 9 through a laterally projecting lever from.

Because turbine 91 and measuring wheel 4 rotate in opposite directions, which corresponds to the load cell 9 applied torque to the difference between the right- and left-rotating moments here the moment M1 for the total mass flow minus the moment M3 from the conveying air.

The differential torque M2 for the supplied Fördergutmenge M2 can thus be obtained directly on the load cell 9 and is forwarded to the evaluation or display device 20, to which also a Tachometer is connected 99th Über die Produktbildung About the product formation M2 xn M2 xn. A method according to claim 1, characterized in that the mass flow M3 of the conveying fluid also according to the Coriolis principle, in an impeller 14 is determined by the change of the drive torque.

A method according to claim 2, characterized in that the measuring wheel 4 and the impeller 14 are driven by electric motor for the promotion of the conveying fluid and at a constant speed, the change in the driving torques M1, M3 is measured and therefrom the difference torque M2 formed becomes.

The method of claim 1, 2 or 3, characterized in that the difference torque M2 by oppositely directed driving torques M1, M3 is formed directly. Device according to claim 5, characterized in that the conveying fluid measuring device 3 by a driven impeller 14 with radial vanes and a torque-measuring device 19 for tapping off the drive torque for the mass flow M3 of the conveying fluid is formed.

Apparatus attack at a single load cell according to claim 6, characterized in that the two torque-measuring devices 9, 19 in opposite directions. Device according to one of claims 5 to 8, characterized in that the feed device 2, 22 by a suction conveyor 70 is formed, wherein between the measuring device 1 for the total mass flow M1 and the measuring device 3 for the conveying air and, if necessary, existing residual dust separation devices such as cyclone separators 72 and filter 75 are provided.

Device according to one of claims 5 to 9, characterized in that the measuring device 1 for the total mass flow M1 and the conveying fluid measuring device 3 for conveying fluid mass flow M3 opposing directions of rotation have.