Preparation method for reducing pH value of furnace carbon black

Abstract

The invention relates to the technical field of carbon black preparation, in particular to a preparation method for reducing the pH value of furnace carbon black. Adding a binder into the granulation water to obtain a mixed solution I; adding a citric acid aqueous solution into the mixed solution I, and uniformly mixing to obtain a mixed solution II; adding the mixed solution II and powdery carbon black into a wet granulator, and forming carbon black granulation water binder citric acid wet particles under the action of stirring teeth of the wet granulator; and drying the carbon black granulation water binder citric acid wet particles in a roller dryer to remove moisture, thereby obtaining the furnace carbon black with reduced pH value. The pH value of the prepared carbon black meets market requirements, rubber products are good in processing safety, the carbon black is easy to disperse uniformly and good in reinforcing performance, citric acid forms oxidation groups on the surface of the carbon black through oxidation, so that the pH value of the furnace carbon black is reduced, citric acid which does not participate in reaction is completely decomposed into carbon dioxide and water, the ash content of the carbon black is not influenced, and the service life of the carbon black is prolonged. And the environment is not influenced.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon black preparation, and more specifically, to a preparation method for reducing the pH value of furnace black carbon black. Background Art

[0002] Furnace black carbon black is produced by burning fuel with excess air in a reaction furnace, where the raw material hydrocarbon undergoes an incomplete combustion and cracking reaction in the reaction furnace to form carbon black, which is then cooled, filtered, collected, granulated, and dried. The surface oxygen content of furnace black carbon black is low, and the carbon black is neutral or weakly alkaline, with a pH value generally ranging from 7 to 10.

[0003] A relatively high pH value of carbon black not only affects the processing safety and vulcanization speed of rubber products, but also affects the dispersion performance and reinforcement performance of carbon black.

[0004] Currently, methods such as adjusting the drying temperature and the ratio of tail gas to air are generally used to reduce the pH value of furnace black carbon black, which have certain limitations and cannot meet the market requirements for product quality. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, an object of one aspect of the present invention is to provide a preparation method for reducing the pH value of furnace black carbon black, and the specific steps of the preparation method are as follows: S1. Add a binder to granulating water to obtain a mixed solution Ⅰ; S2. Add an aqueous citric acid solution to the mixed solution Ⅰ prepared in S1 and mix evenly to obtain a mixed solution Ⅱ; S3. Add the mixed solution Ⅱ prepared in S2 and powdered carbon black to a wet granulator, and under the action of the 15 stirring teeth of the wet granulator, form carbon black granulating water binder citric acid wet particles; S4. Dry the carbon black granulating water binder citric acid wet particles in a drum dryer to remove moisture and obtain furnace black carbon black with a reduced pH value.

[0006] Preferably, in S1, the mass ratio of the binder to the granulating water is 0.5:100 - 5:100.

[0007] Preferably, in S2, the mass percentage of the aqueous citric acid solution is 3% - 20%.

[0008] Preferably, in S2, the mass ratio of the mixed solution Ⅰ to the aqueous citric acid solution is 500:1 - 100:1.

[0009] Preferably, in S2, the aqueous citric acid solution is prepared from citric acid and water.

[0010] Preferably, in S2, the citric acid is industrial-grade citric acid with a citric acid content of ≥99% Preferably, the feeding rate of the citric acid aqueous solution in S2 is 5 kg / h - 40 kg / h.

[0011] Preferably, the stirring frequency of the wet granulator in S3 is 15 - 45 Hz, and the time is 2 - 5 min.

[0012] Preferably, the mass ratio of the mixed solution II to the powdered carbon black in S3 is 1:1 - 2:1.

[0013] Preferably, the outlet temperature of the carbon black from the drum dryer in S4 is 140°C - 240°C. The beneficial effects of the present invention are as follows: The pH value of the carbon black prepared by the present invention meets the market demand, the processing safety of rubber products is good, the carbon black is easily and evenly dispersed, and the reinforcing performance is good. Citric acid forms oxidation groups on the surface of the carbon black through oxidation, thereby reducing the pH value of the furnace black. The unreacted citric acid is completely decomposed into carbon dioxide and water, which has no effect on the ash content of the carbon black and has no impact on the environment.

[0014] The additional aspects and advantages of the present invention will become apparent in the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, wherein: Figure 1 is the equipment flow chart of the embodiment of the present invention; Wherein, Figure 1 The corresponding relationship between the reference numerals and the component names in the drawings is as follows: 1 is a citric acid preparation tank, 2 is a binder tank, 3 is a granulation water tank, 4 is a citric acid aqueous solution pump, 5 is a binder pump, 6 is a granulation water pump, 7 is a granulation water flow meter, 8 is a binder flow meter, 9 is a citric acid flow meter, 10 is a granulation water flow regulating valve, 11 is a binder flow regulating valve, 12 is a citric acid aqueous solution flow regulating valve, 13 is a mixer, 14 is a powdered carbon black storage tank, 15 is a wet granulator, 16 is a drum dryer, 17 is a tail gas low-nitrogen burner or a tail gas combustion furnace, 18 is an airtight valve, 19 is a citric acid aqueous solution check valve, and 20 is a binder check valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] In order to more clearly understand the above objects, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the drawings and specific embodiments. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments may be combined with each other.

[0017] In the following description, many specific details are set forth to provide a thorough understanding of the present invention. However, the present invention may be practiced in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited by the specific embodiments disclosed below.

[0018] The device of the embodiment of the present invention includes a citric acid preparation control system, a granulation water and binder preparation control system, a mixer 13, a powdered carbon black storage tank 14, a wet granulator 15, a drum dryer 16, and a tail gas low-nitrogen burner 17 or a tail gas combustion furnace 17. The citric acid preparation control system includes a citric acid preparation tank 1, a stirrer, a citric acid aqueous solution pump 4, a citric acid flowmeter 9, and a citric acid aqueous solution flow regulating valve 12; the granulation water and binder preparation system includes a granulation water tank 3, a binder tank 2, a granulation water pump 6, a binder pump 5, a granulation water flowmeter 7, a binder flowmeter 8, a granulation water flow regulating valve 10, and a binder flow regulating valve 11; the mixer 13 is installed behind the binder pipeline, the granulation water pipeline, and the citric acid aqueous solution interface; it is connected to the wet granulator 15 through a mixed liquid pipeline; the powdered carbon black storage tank 14 is connected to the wet granulator 15 through an airtight valve 18; the wet granulator 15 is connected to the drum dryer 16 through a feeding pipeline; a carbon black outlet is provided at the tail of the drum dryer 16.

[0019] Example 1 S1. Control the granulation water flow regulating valve 10 and the binder flow regulating valve 11 to add the binder (liquid lignin) and granulation water into the mixer 13 to obtain a mixed liquid Ⅰ, and the mass ratio of the binder to the granulation water is 3:100. S2. In the citric acid preparation tank 1, citric acid and water are prepared into a citric acid aqueous solution with a mass percentage of 3%-12% through a stirrer. There are two citric acid preparation tanks, one in use and one in standby. Control the citric acid aqueous solution flow regulating valve 12 to add the citric acid aqueous solution into the mixed liquid Ⅰ prepared in S1 of the mixer 13 and mix evenly to obtain a mixed liquid Ⅱ. The adding speed of the citric acid aqueous solution is 5 kg / h - 40 kg / h, and the flow rate of the citric acid aqueous solution is adjusted according to the pH value of the carbon black. S3. Add the mixed liquid Ⅱ prepared in S2 of the mixer 13 and powdered carbon black into the wet granulator 15. The mass ratio of the mixed liquid Ⅱ to the powdered carbon black is 2:1. Under the action of the stirring teeth of the wet granulator 15, carbon black granulation water binder citric acid wet particles are formed, the stirring frequency is 40 Hz, and the time is 2.5 min. S4. The carbon black binder citric acid wet particles are heat-exchanged with the hot flue gas from the tail gas low-nitrogen burner in the drum dryer 16 to remove moisture, and the carbon black outlet temperature is 140 - 240 °C.

[0020] The technical indexes of the furnace black prepared in this embodiment are iodine adsorption value: 30 - 160 g / kg, DBP absorption value: 110 - 14010 -5 m3 / kg, Coloring strength: 40 - 140%, Nitrogen adsorption specific surface area: 30 - 150 10 3 m 2 / kg, pH value: 6 - 8, Volatile matter: ≤1.2%, Loss on heating: ≤0.3%, Average particle hardness ≤50 cN, Ash content ≤0.7%.

[0021] Example 2 S1. Control the granulation water flow regulating valve 10 and the binder flow regulating valve 11 to add the binder (liquid lignin) and granulation water into the mixer 13 to obtain the mixed liquid Ⅰ, and the mass ratio of the binder to the granulation water is 0.5:100; S2. In the citric acid preparation tank 1, stir citric acid and water to prepare a citric acid aqueous solution with a mass percentage of 12% - 20%. There are two citric acid preparation tanks, one in use and one in reserve. Control the citric acid aqueous solution flow regulating valve 12 and then add the citric acid aqueous solution into the mixed liquid Ⅰ prepared in S1 of the mixer 13 to mix evenly to obtain the mixed liquid Ⅱ. The adding speed of the citric acid aqueous solution is 5 kg / h - 40 kg / h, and adjust the flow of the citric acid aqueous solution according to the pH value of the carbon black; S3. Add the mixed liquid Ⅱ prepared in S2 of the mixer 13 and the powdered carbon black into the wet granulator 15. The mass ratio of the mixed liquid Ⅱ to the powdered carbon black is 1:1. Under the action of the stirring teeth of the wet granulator 15, form carbon black granulation water binder citric acid wet particles, with a stirring frequency of 30 Hz and a time of 3 min; S4. Exchange heat between the carbon black binder citric acid wet particles and the hot flue gas from the tail gas low-nitrogen burner in the drum dryer 16 to remove moisture, and the carbon black outlet temperature is 140 - 240 °C.

[0022] The technical indexes of the furnace black prepared in this example are: Iodine adsorption value: 30 - 160 g / kg, DBP absorption value: 70 - 110 10 -5 m 3 / kg, Coloring strength: 40 - 140%, Nitrogen adsorption specific surface area: 30 - 150 10 3 m 2 / kg, pH value: 6 - 8, Volatile matter: ≤1.2%, Loss on heating: ≤0.3%, Average particle hardness ≤50 cN, Ash content ≤0.7%.

[0023] Example 3 S1. Control the granulation water flow regulating valve 10 and the binder flow regulating valve 11 to add the binder (liquid lignin) and granulation water into the mixer 13 to obtain the mixed liquid Ⅰ, and the mass ratio of the binder to the granulation water is 1.5:100; S2. In the citric acid preparation tank 1, citric acid and water are mixed by a stirrer to form an aqueous citric acid solution with a mass percentage of 3% - 20%. There are two citric acid preparation tanks, one in use and one in reserve. Control the flow regulating valve 12 of the aqueous citric acid solution and then add the aqueous citric acid solution to the mixed solution Ⅰ prepared in S1 in the mixer 13 to mix evenly to obtain the mixed solution Ⅱ. The addition speed of the aqueous citric acid solution is 5 kg / h - 40 kg / h, and the flow rate of the aqueous citric acid solution is adjusted according to the pH value of the carbon black. S3. Add the mixed solution Ⅱ prepared in the mixer 13 in S2 and the powdered carbon black to the wet granulator 15. The mass ratio of the mixed solution Ⅱ to the powdered carbon black is 1.2:1. Under the action of the stirring teeth of the wet granulator 15, carbon black granulation water binder citric acid wet particles are formed. The stirring frequency is 30 Hz and the time is 3 min. S4. Heat exchange the carbon black binder citric acid wet particles with the hot flue gas from the tail gas low-nitrogen burner in the drum dryer 16 to remove moisture. The carbon black outlet temperature is 140 - 240 °C.

[0024] The technical indexes of the furnace black prepared in this embodiment are iodine absorption value: 30 - 160 g / kg, DBP absorption value: 70 - 110 10 -5 m 3 / kg, coloring strength: 40 - 140%, nitrogen adsorption specific surface area: 30 - 150 10 3 m 2 / kg, pH value: 6 - 8, volatile matter: ≤1.2%, heating loss: ≤0.3%, average particle hardness ≤50 cN, ash content ≤0.7%.

[0025] The above are only preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can also have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for reducing the pH value of furnace carbon black, characterized in that: The specific steps of the preparation method are: S1. Adding the binder to the granulation water to obtain a mixed solution Ⅰ; S2. adding the citric acid aqueous solution to the mixed solution Ⅰ prepared in S1 to mix the mixed solution Ⅱ uniformly; S3. The mixed solution prepared in S2 Ⅱ and powdered carbon black are added to the wet granulator 15, and the wet granulator 15 is used to form carbon black granulated water binder citric acid wet particles under the action of stirring teeth; S4. Dry the wet particles of carbon black granulation water binder citric acid in a drum dryer 16 to remove moisture and obtain furnace carbon black with reduced pH value.

2. A method for preparing furnace carbon black with reduced pH value according to claim 1, characterized in that: The mass ratio of the binder to the granulation water in S1 is 0.5:100-5:

100.

3. A method for preparing furnace carbon black with reduced pH value according to claim 1, characterized in that: The mass percentage of the citric acid aqueous solution in S2 is 3%-20%.

4. A method for preparing furnace carbon black by reducing pH value according to claim 1, characterized in that: The mass ratio of the S2 mixed solution I to the citric acid aqueous solution is 500:1-100:

1.

5. A method for preparing furnace carbon black by reducing pH value according to claim 4, characterized in that: The citric acid aqueous solution in S2 is prepared from citric acid and water.

6. A method for preparing furnace carbon black by reducing pH value according to claim 4, characterized in that: The citric acid in S2 is industrial grade citric acid, and the citric acid content is ≥99%.

7. A method for preparing furnace carbon black by reducing pH value according to claim 4, characterized in that: The speed of adding the citric acid aqueous solution into S2 is 5kg / h-40kg / h.

8. A method for preparing furnace carbon black by reducing pH value according to claim 1, characterized in that: The stirring frequency of the wet granulator 15 in S3 is 15-45 Hz, and the stirring time is 2-5 min.

9. A method for preparing furnace carbon black by reducing pH value according to claim 1, characterized in that: The mass ratio of the mixed liquid II to the powdered carbon black in S3 is 1:1-2:

1.

10. A method for preparing furnace carbon black by reducing pH value according to claim 1, characterized in that: The carbon black outlet temperature of the drum dryer 16 in S4 is 140°C-240°C.

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