SU645593A3 - Method of isolating carbon black from aqueous suspension - Google Patents

Description

one

This invention relates to a process for separating carbon black from a water suspension used for water purification (as activated carbon in the form of tablets), as a black pigment for rubber, plastics, printing ink, etc., as well as for use in electric batteries.

There is a method of extracting carbon black from an aqueous suspension, which includes adding a hydrocarbon liquid to an aqueous suspension of carbon black with stirring to form carbon black agglomerates, separating black carbon agglomerates from water with feeding the hydrocarbon liquid in an amount of 1-10 by the amount of liquid supplied to the mixing stage 1.

However, this method is expensive because of the large amount of hydrocarbon liquid used, which entails an increase in the amount of equipment that is used in the implementation of the known method.

The purpose of the invention is to increase the economy of the process of soot extraction.

This goal is achieved by the fact that when the method includes the addition of a hydrocarbon liquid to an aqueous suspension of soot with stirring to form soot agglomerates, the separation of soot agglomerates from water with the supply of hydrocarbon liquid, the last stage of separation is served in an amount of 0.2-0.9 by quantity

fluid supplied to the mixing stage.

The difference of the proposed method lies in the fact that the hydrocarbon liquid is fed to the separation stage in the amount

0.2-0.9 of the amount of liquid supplied to the mixing stage.

Selection of the specified ratio of hydrocarbon (auxiliary) liquid at the stage of mixing and separation of carbon black

due to the fact that such an amount of auxiliary liquid, with an effective release of soot, removes a smaller amount of auxiliary liquid from the process from aqueous suspensions, requires

smaller sizes of tanks, pumps and pipelines, as well as smaller mosh, nosti pumps, thereby increasing the efficiency of the process compared with the prototype. As an auxiliary fluid

They can use liquids that can agglomerate soot particles, do not mix with water and have a specific gravity lower than that of water. For this purpose, suitable

gasoline, naphtha, toluene, gasoline or chlorinated hydrocarbons, such as carbon tetrachloride.

In order to ensure close contact between the soot particles and the auxiliary liquid at the mixing stage, turbulent movement of the soot slurry with water is maintained. For this purpose, a mixing power of 1.5-10 liters is very suitable. s / mz

As a result of the contact of the suspended particles of soot with the auxiliary liquid during mixing, the uniform distribution of soot is disturbed and the formation of relatively large particles in water, or agglomerates; particle sizes are up to 1 mm or more.

For the blending operation, it is recommended to supply only the required amount of an appropriate auxiliary liquid to bind the soot particles in order to obtain agglomerates so that no free auxiliary liquid remains. The amount of auxiliary liquid required for this is usually somewhat larger than the corresponding total porous volume of soot that needs to be agglomerated. The auxiliary liquid is supplied to the mixing stage in a weight ratio to the weight of the carbon black particles from 2: 1 to 6: 1.

The proposed method is carried out at a temperature of from 40 to 160 ° C. The most optimal pressure is determined by the component pressures of the particular auxiliary fluid and water. Typically, this pressure is between 1 and 15 kg / cm.

At the stage of displacement under turbulent conditions, the formation of soot agglomerates and auxiliary liquid in water occurs, and at the stationary separation stage, the agglomerates enter an excess of auxiliary liquid. Thus, all agglomerates are enclosed in an auxiliary liquid.

The stationary phase of the auxiliary liquid comprises from 30 to 80% of the liquid phase present in the separation stage. Positive results are obtained when the stationary phase of the auxiliary liquid is about 50% of the total volume of the liquid; the residence time of the auxiliary liquid in the steady state is approximately 30-120 minutes.

After removal, the soot agglomerates, as a rule, take with them a certain amount of auxiliary liquid. Adding this liquid to the separation operation should be carried out between the water and the stationary phases, or along the line of their separation.

The agglomerates are mechanically removed from the stationary phase of the auxiliary liquid so that only a small amount of the auxiliary liquid is removed together with the agglomerates.

Soot agglomerates removed from the stationary phase are quite suitable for their further processing in order to obtain dry soot or dry soot tablets. For this, the carbon black agglomerates are free from the auxiliary

fluid. Such an operation can be carried out by treating the agglomerates with superheated steam so that all the auxiliary liquid is evaporated.

The auxiliary liquid can be removed by evaporation by using the fluidization of a layer of soot agglomerates, and the fudization is obtained using hot gas or steam heated to 150-350 ° C.

Dry soot, obtained in the form of particulate tablets, is characterized by very high porosity, very small particle sizes and a large specific surface area. Bulk density is from 0.01 to

0.16 g / cm.

FIG. Figure 1 shows an installation diagram for carrying out the proposed method; in fig. 2 is the same as the embodiment. Mixing 1 and separation (separator) 2 chambers are placed in a common elongated body and separated from one another by a funnel partition 3 having a central opening 4. A shaft 5 driven by an electric motor 6, which is located outside (outside the body), passes through the bottom of the body. The shaft 5 forms an agitator with blades 7 in the mixing chamber 1. Through the tubes 8 and 9 located near the bottom of the mixing chamber, the soot suspension and the auxiliary liquid are supplied, respectively. The two kinds of these liquids are mixed under turbulent conditions, resulting in the formation of agglomerates of soot and auxiliary liquid, which remain in the water in the dispersion state.

The aqueous dispersion of the carbon black agglomerates enters the separation chamber 2 through the opening 4 under the action of supplying the indicated liquids to the mixing tank. In the chamber 2, at a level lying above the level of the opening 4, there is a pipe 10 through which the chamber is removed from

soot-free water, and soot agglomerates in stationary water layer 11 rise to stationary auxiliary liquid layer 12. A stationary layer of water is maintained by feeding water.

dispersions with soot agglomerates through the opening 4, and the stationary layer of the auxiliary liquid — by supplying the auxiliary liquid through the pipe 13 entering the separation chamber 2 approximately

in the center (height), or directly

below line 14, the separation of two stationary layers AND and 12.

Particulate agglomerates trapped in the stationary layer 12 of the auxiliary liquid are removed (lifted) from the stationary layer by means of a screw 15 and removed from the separation chamber 2. The screw 15, whose shaft is driven by the electric motor 16, is located in a hollow tube 17 having an open the end above the surface 18 of the stationary layer of the auxiliary liquid, and the second end of this tube lies above the level of the first, open, end. The tube 17 is usually located above the upper end of the chamber 2 and has an inner diameter greater than the diameter of the screw 15 so that all the auxiliary liquid trapped by the soot agglomerates flows back into the chamber 2 along the walls of the tube 17. At one end, the screw 15 enters the stationary layer 12 from above.

The agglomerates lifted by the screw 15 are deposited in the tube 19 connected to the tube 17.

Wet soot agglomerates containing soot particles and absorbed auxiliary liquid are fed through tube 19 to an evaporation column 20, in the upper part of which there are inclined planes 22 arranged in a zigzag manner in order to properly distribute and spray the agglomerates, which are supplied to the lower part 23 of the evaporator.

The contact between the agglomerates and the planes 22 is carried out with heating so that the auxiliary liquid evaporates from the agglomerates.

At the bottom 23 of the evaporator, a spray device 24 is installed, which is fed through pipe 25 and by means of which hot heavy oil is sprayed. It is recommended that the temperature of this oil be above the boiling point (or boiling point range) of the auxiliary liquid and all absorbed auxiliary liquid evaporate when the agglomerates come in contact with a splash of hot oil, after which these agglomerates fall into the stationary layer 26 of oil. The vaporized auxiliary liquid is discharged through the suction pipe 27, and the vapors preferably heat the planes 22. If necessary, the planes 22 can also be heated by other means (not shown), for example, using superheated steam. The agglomerates, constantly and independently J, the complementary oil layer 26, can partially decompose, and the soot-containing oil through the pipe 28 is removed from the evaporator.

In the second variant of the installation (Fig. 2), the mixing and separation chamber is made in the form of separate devices, and the executive column is in the form of a chamber with a fluidized bed. Mixing

the chamber 1 is set at an angle to the separation chamber 2 so as to provide an inclination corresponding to the angle of inclination of the screw 15. These two separate tanks 1 and 2 are connected to each other through an aperture 4, which serves to carry dispersion from the black agglomerates through it into the water. Part of the tube 17 is replaced by metal

tube 29, around which there is a jacket 30, which serves to take the auxiliary liquid, which comes together with the agglomerates from the tube 17, and in order to guide this liquid again through the pipe 31

into the separation chamber 2.

From the metering device 32, dry agglomerates through pipe 33 enter space 34 above grate 35 of fluidized bed chamber 36 for agglomerates. The agglomerates are fluidized by superheated steam with a temperature of, for example, 350 ° C supplied through pipe 38, this steam is removed with the aid of a cyclone 39 through pipe 40. Spiral coil 41 for

the hot oil provides heat exchange with the layer 37, and after soaking in the chamber 36, the advanced soot pellets are removed through the valve 42 through the pipe 43 for further processing. Dried pills

the soot is substantially free of the absorbed auxiliary liquid.

Example 1. To an aqueous soot suspension with a temperature of 100 ° C, supplied in an amount of 1500 kg / h of water and 25 kg / h of soot, is added while moving gasoline (with a final boiling point of 90 ° C) in an amount of 100 kg / h, per the separation step gasoline is fed in an amount of 50 kg / h (which is 0.5 quantities of gasoline supplied to the transfer step). The pressure at the stage of displacement and separation is 5.5 kgf / cm2. At the separation stage, a layer of 50 liters of gasoline is formed, which is

50% of the total liquid phase, the residence time of gasoline in the layer is up to 120 minutes. Water is removed in the amount of 1475 kg / h, wet soot agglomerates are removed from the layer in the amount of 200 kg / h (and

75%, water (12.5% and carbon black (12.5%)), 2000 kg / h of hot oil (containing carbon black) are added at 280 ° C at a pressure of 4 kgf / cm, resulting in water with gasoline from agglomerates evaporate:

As a result, an oil nasal slurry stream was released in an amount of 525 kg / h (of which 25 kg / h of carbon black and 0.5% gasoline). Example 2. To an aqueous suspension of carbon black supplied in an amount of 1000 kg / h of water and 20 kg / h of carbon black, 80 kg / h of gasoline and 20 kg / h of gasoline are added with stirring to the separation stage (which is 0.25 gasoline supplied

to the mixing stage). Water from the separation separation is removed in the amount of 980 kg / h and the wet granules in the amount of 140 kg / h (of which 20 kg / h of water, 20 kg / h of soot and gasoline the rest). The pressure at the stage of mixing and separation is 1--5 kgf / cm. The wet agglomerates are dried at atmospheric pressure in a fluidized bed with superheated steam at 350 ° C. As a result, 20 kg / h of dry soot granules (tablets) are obtained, which do not stick together and with a small pressure can be scattered into dry soot.

Example 3. Carried out as in example 1, but gasoline is added to the carbon black gas mixture; gasoline is fed to the separation stage in an amount of 90 kg / h (which is 0.9 the amount of gasoline supplied to the mixing stage); wet agglomerates are removed in an amount of 240 kg / h (moreover, there is 80% gasoline, 10% WATER and 10% carbon black).

Fuel oil (containing soot) is added to wet agglomerates at 280 ° C in an amount of 2000 kg / h. With a pressure of 4 kgf / cm

water and gasoline from

agglomerates are evaporated.

As a result, an oil nasal slurry stream was released in the amount of 525 kg / h (of which 25 kg / h of carbon black and 0.55% gasoline).

Claims (1)

Invention Formula A method of separating carbon black from an aqueous suspension, comprising adding to the aqueous soot suspensions of hydrocarbon liquids with stirring to form soot agglomerates, separating soot agglomerates from water with feeding of hydrocarbon liquids, so that, in order to increase the efficiency of the process, the hydrocarbon liquid is fed to the separation stage in an amount 0.2-0.9 of the amount of liquid supplied to the mixing stage. Information sources, taken into account during the examination 1. USSR Patent No. 434639, cl. In About ID 12/00, 1970. ABOUT