DE9002158U1 - Device for determining the abrasion resistance of activated carbon - Google Patents

Description

Description

The innovation concerns a device for determining the abrasion resistance of activated carbons.

The device is characterized by an outer tube, a riser tube coaxial with the outer tube, the inner diameter of the outer tube being a factor of 3 to 10 larger than the inner diameter of the riser tube, an approximately funnel-shaped bottom corner connected to the lower end of the outer tube with a central, vertical outlet channel, the side of which is fixed at a distance from the lower end of the riser tube, a baffle with a larger diameter than the inner diameter of the riser tube, which is arranged at a distance above the upper end of the riser tube, and a gas outlet with a sieve above the baffle surface.

Details iLid design options for the device and its application are explained with the help of the drawing. It shows:

Fig. 1 shows a schematic longitudinal section through the device,

Fig. 2 a longitudinal section through the enlarged impact body and

Fig. 3 shows a longitudinal section through the enlarged base piece.

When transporting activated carbon, filling it into filters and removing it from them, as well as when backwashing with water and air and during thermal reactivation, the activated carbon is subjected to mechanical stress. This stress leads to grain refinement and dust-like abrasion. This is undesirable as it increases the filter resistance.

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and carbon losses occur during backwashing. With the innovative device, key figures for assessing the abrasion resistance and mechanical hardness of activated carbon can be obtained under realistic conditions.

The main parts of the device are the outer tube (1), to the lower end of which is connected to an approximately funnel-shaped base piece (2), the central riser pipe (3), the impact body (4) and the sieve (5). The base piece (2) is detachably connected to the outer tube (1) in a known manner not shown in detail. The base piece (2) has a central, vertical gas inlet channel (7) through which gas, in particular air, is introduced under pressure from below and flows upwards through the riser pipe (3) during operation. In Fig. 1, a gas line (8) with a quick-closing valve (9), rotameter (10) and pressure gauge (11) is indicated, which can be connected to the gas inlet channel (7). The gas comes from a source not shown.

Several support webs (13) are attached to the riser pipe (3) near the lower end and also in the upper area, which ensure that the pipe (3) is centered in the outer pipe (1) and in the base piece (2). The riser pipe (3) is preferably designed to be removable together with its support webs (13).

A head piece (6) is attached to the upper end of the outer tube (1) and is detachably connected to the outer tube (1). Struts (15) are attached to the head piece (6) and hold a threaded sleeve (16) into which a threaded spindle (4a) is screwed. The spindle (4a) that belongs to the impact body (4) allows the impact body to be attached in a height-adjustable manner. The head piece (6) also has a gas outlet (18) to which a suction device (not shown) can be connected.

An exemplary design of the impact body (4) is shown enlarged in Fig. 2. The impact body, which is arranged above the riser pipe (3), has a largest diameter (D) and it has a recessed impact surface (4b) which is recessed by a height (a). The horizontal area of the impact surface (4b) has the diameter (d). Another shape of the impact body (4) and the impact surface (4b) is possible.

As can be seen best from Fig. 3, there is a vertical distance (D) between the lower end of the riser pipe (3) and the mouth of the gas inlet channel (7). The inner wall of the base piece (2) has a roughly conical shape with a cone angle (A), measured against the vertical (S), of approximately 25 to 40°.

When the device is in operation, a sample of activated carbon is filled into the base piece (2) and partially into the outer tube (1), whereby the riser pipe (3) is initially kept as free as possible. The gas, in particular air, flows from below through the channel (7) and carries the activated carbon upwards through the riser pipe (3). The carbon hits the impact surface (4b) and falls back into the base piece (2), from where it is again carried upwards through the riser pipe (3). The gas is sucked upwards through the sieve (5) and the outlet (18), whereby any coal dust that is formed is carried along. The mesh size of the sieve (5), which is, for example, in the range of 0.1 to 1 mm, determines the maximum grain size of the discharged dust. After a certain test time of, for example, one hour, the experiment is terminated and an investigation is made into how the activated carbon remaining in the apparatus has changed compared to its original state, especially in terms of weight and core structure.

For precise investigations, the following procedure can be used: First, a sieve analysis is carried out on the activated carbon

carried out, then the individual fractions are recombined and dried. Drying takes place, for example, at 12O ⁰ C. During sieve analysis, the dust fraction is removed from the measuring apparatus according to the mesh size of the sieve (5); this dust fraction can, for example, cover a grain size range of 0 to 0.2 mm. Grains that are too coarse, e.g. > 3 mm, are also removed from the activated carbon to prevent blockages in the measuring apparatus. After drying, the weighed activated carbon sample is filled into the test apparatus. During filling, the upper end of the riser tube (3) is covered so that the carbon only fills the base section (2) and the lower section of the outer tube (1), but not the riser tube (3).

The air supplied through the pipe (8) must be oil-free and as dry as possible. At a specified air speed, the carbon, which constantly trickles down the base piece (2) to the gas inlet channel (7), is conveyed upwards through the riser pipe (3) and hits the impact surface (4b) before falling back down the outer pipe (1). Gas and dust are constantly sucked out through the outlet (18). After the test has been completed, the activated carbon is dried and weighed again and the dust formation is calculated from the weight loss. A new sieve analysis shows the grain refinement that occurred during the test.

Example:

A coal sample with a grain size in the range of 0.2 to 2 mm, pretreated in the manner described, is shaken in a quantity of 100 ml and tested for one hour in the apparatus shown in the drawing. The apparatus has the following details:

The outer tube (1) made of glass has a length of 400 mm, an inner diameter of 52 mm and a wall thickness of 4 mm. The

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The riser pipe (3) is made of stainless steel, it has a length of 385 mm, an inner diameter of 11 mm and a wall thickness of 2 mm. The base piece (2), also made of stainless steel, has a height (H), see Fig. 1, of 33 mm and a cone angle (A) of 23°. The diameter of the gas inlet channel (7) is 2.5 mm at the mouth end. The distance (B) between the lower end of the riser pipe and the base piece is 9 mm. The impact body (4) has an outer diameter (D) of 40 mm, the diameter (d) of the impact surface (4b) is 32 mm. The impact surface is recessed by a height (a) of 1 mm and is located at a distance of 15 mm above the upper end of the riser pipe. The mesh size of the sieve (5) is 0.2 mm.

Claims (3)

Protection claims 1. Device for determining the abrasion resistance of activated carbons, characterized by an outer tube, a riser tube coaxial to the outer tube, the inner diameter of the outer tube being a factor of 3 to 10 larger than the inner diameter of the riser tube, a vertical gas inlet channel adjoining the lower end of the outer tube, approximately 150 mm wide, the mouth of which is at a distance from the lower end of the riser tube, an impact surface with a larger diameter than the inner diameter of the riser tube, which is arranged at a distance above the upper surface of the riser tube, and a gas outlet with a sieve above the impact surface. 2. Device according to claim 1, characterized in that the impact surface is mounted so as to be height adjustable. 3. Device according to claim 1 or 2, characterized in that the riser pipe is arranged centrally in the outer pipe and in the base piece by means of support webs.