A method for preparing high-quality granulated carbon black by pyrolysis carbon slag

Abstract

The present invention relates to a method for preparing high-quality granulated carbon black from pyrolysis carbon slag, which comprises the following steps: (1) grinding the pyrolysis carbon slag to obtain carbon powder; (2) conveying the obtained carbon powder to a granulation process; (3) granulating, wherein the particle size of the granulated carbon black is controlled to be between 0.5-2 mm; (4) drying the granulation moisture in the carbon black to less than 2wt%, thereby obtaining a finished granulated carbon black. The present invention is aimed at the unique properties of the pyrolysis carbon powder, and can achieve reliable and stable granulation through raw material pre-inspection control, improved feeding process, and adjustment of granulation process parameters, thereby obtaining pyrolysis carbon black with the same granular properties as commercial carbon black.

Description

Technical Field

[0001] The invention relates to a method for preparing high-quality granulated carbon black from pyrolysis carbon slag, which can realize stable granulation of pyrolysis carbon slag into high-quality pyrolysis carbon black. Background Art

[0002] At present, with the rapid development of waste tire pyrolysis technology, waste tire pyrolysis enterprises are also blooming in many places, which directly leads to the rapid increase in the price of waste tire raw materials, and various production enterprises are facing the dilemma of serious profit decline. In view of this, the development of high-value pyrolysis products has become the top priority of the industry.

[0003] Pyrolysis carbon black is one of the main products of waste tire pyrolysis, with a yield of about 35%. However, due to its high ash content and low structure, it is difficult to use directly as a raw material in the downstream industrial chain, and its value is the lowest. Now many people still use pyrolysis carbon black as coal for direct combustion, or as a low-end filler after simple grinding. Its value is only 5-20% of commercial carbon black, and it is a low value-added product.

[0004] Therefore, in order to achieve rapid and vigorous development of the waste tire pyrolysis industry, it is necessary to utilize the pyrolysis carbon black in a high-value manner.

[0005] At present, cracking enterprises usually grind cracking carbon residue directly into powder to increase part of the profit. However, cracking carbon powder can only be packaged in 20kg woven bags during use because it is easy to fly. Then it is manually fed, which will cause serious secondary pollution. Therefore, how to solve the secondary pollution has become a difficult problem that the industry needs to solve urgently. Summary of the invention

[0006] The present invention aims to solve the problem in the prior art that pyrolysis carbon powder is easy to fly during use and causes serious secondary pollution, and provides a new method for preparing high-quality granulated carbon black from pyrolysis carbon residue.

[0007] A method for preparing high-quality granulated carbon black by pyrolysis of carbon slag, comprising the following steps:

[0008] (1) grinding the pyrolysis carbon residue to obtain carbon powder;

[0009] (2) transporting the obtained carbon powder to a granulation process;

[0010] (3) Granulation is performed, and the particle size of the granulated carbon black is controlled between 0.5-2 mm;

[0011] (4) Drying the granulation moisture in the carbon black to less than 2 wt %, thereby obtaining a finished granulated carbon black.

[0012] The method for preparing high-quality granulated carbon black of the present invention preferably performs a preliminary inspection on the ground carbon powder in step (1): 100-300g of the carbon powder is taken to inspect the toluene transmittance and 45 micron sieve residue, and the toluene transmittance is required to be greater than 60% and the 45 micron sieve residue is less than 1000ppm. The qualified carbon powder is sent to the next process.

[0013] The method for preparing high-quality granulated carbon black of the present invention preferably adopts a feeding method of a variable diameter screw in step (2), and the variable diameter ratio is 0.4 to 0.8.

[0014] The method for preparing high-quality granulated carbon black of the present invention preferably comprises uniformly spraying and mixing carbon powder and granulation water in step (3) to obtain particles of a certain particle size under high-speed stirring.

[0015] The method for preparing high-quality granulated carbon black of the present invention preferably comprises heating the granulator wall temperature to maintain at 120±5°C before feeding in step (3); after the temperature stabilizes, the valve openings of the carbon powder and granulation water are controlled, and the two are mixed and fed in a ratio of 45±10wt% of the granulation water.

[0016] In the method for preparing high-quality granulated carbon black of the present invention, the granulated carbon black preferably enters a high-temperature drum drying device, and the drum outlet temperature is controlled between 140-155°C.

[0017] Another aspect of the present invention provides a pelletized carbon black prepared by the above preparation method.

[0018] The present invention aims at the unique properties of pyrolysis carbon powder, and can realize reliable and stable granulation through raw material pre-inspection control, improved feeding process, and adjustment of granulation process parameters, so as to obtain pyrolysis carbon black with the same granular properties as commercial carbon black. In this way, pyrolysis carbon black can be packaged in various forms such as ton bags, half-ton bags, 20kg low-melting-point bags, 20kg woven bags, etc., and can realize automatic feeding, which perfectly solves the secondary pollution problem in the downstream application of pyrolysis carbon black. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A diagram showing the production apparatus for the method for preparing high-quality pelletized carbon black used in the present invention.

[0020] Reference numerals: 1-silo 2-star discharge valve 3-reducing screw 4-granulator 5-sampling port 6-granulation water valve 7-drum drying 8-packaging machine DETAILED DESCRIPTION

[0021] The invention aims at the waste tire pyrolysis carbon residue, adopts a wet granulation process, and obtains pyrolysis carbon black with the same granular properties as commercial carbon black through stable control before feeding.

[0022] The method for preparing high-quality granulated carbon black by pyrolysis carbon slag of the present invention is described in detail below, which comprises the following steps:

[0023] 1. Raw material inspection

[0024] If the cracking carbon residue is to be granulated, it must meet the granulation requirements. First, the cracking carbon residue must be ground, and 100-300g of carbon powder must be tested for toluene transmittance and 45 micron sieve residue. The toluene transmittance must be greater than 60% and the 45 micron sieve residue must be less than 1000ppm. The qualified carbon powder will be sent to the next process.

[0025] 2. Feeding

[0026] The quality of carbon black granulation depends on the stability of raw material control. The quality of the ground cracked carbon powder itself is relatively unstable due to the uneven particle size distribution. Therefore, the feeding process must be strictly controlled to ensure the stability of carbon powder feeding on the one hand and the stability of the ratio of carbon powder to granulation water on the other hand. The present invention adopts the feeding method of variable diameter spiral (variable diameter ratio of 0.4 to 0.8) which is unique to this industry. The loose carbon powder is compacted and stably transported to the granulator, which can fully ensure the stability of carbon powder feeding.

[0027] The design of the variable diameter screw is based on the production capacity of the upstream discharge valve and the downstream granulator. By reasonably controlling the variable diameter ratio, the purpose of compacting the carbon powder and feeding it stably can be achieved. Through this variable diameter screw stable feeding device, the stable time of the granulation process can be increased by more than 100%.

[0028] 3. Granulation

[0029] Granulation is the core of the whole process. Its principle is to obtain particles of a certain size by uniformly spraying and mixing carbon powder and granulation water under high-speed stirring.

[0030] Before feeding, heat the granulator wall temperature to keep it at 120±5℃ to reduce the wall hanging phenomenon during the granulation process. After the temperature stabilizes, the valve opening of carbon powder and granulation water is controlled, and the two are mixed and fed in a certain proportion (granulation water accounts for 45±10%). Randomly sample at the sampling port at the tail end, and visually control the particle size of granulated carbon black to be between 0.5-2mm. If it is too large or too small, adjust the granulation water feed valve for control.

[0031] 4. Drying

[0032] The granulated carbon black enters the high-temperature drum drying device, and the drum outlet temperature is controlled between 140-155°C to ensure that the granulation moisture in the carbon black is dried to less than 2%, thereby obtaining the finished granulated carbon black.

[0033] 5. Packaging

[0034] The finished granulated carbon black enters the packaging machine (three specifications: ton bag, half-ton bag, and 20kg bag) for packaging.

[0035] The preparation method of the high-quality granulated carbon black of the present invention is described below through specific examples.

[0036] Example 1

[0037] The cracking carbon residue was ground, and 100 g of the ground carbon powder was taken to test the toluene transmittance and 45 micron sieve residue. The test results were 82% for toluene transmittance and 326 ppm for 45 micron sieve residue, both of which met the granulation requirements.

[0038] When the wall temperature of the granulator 4 rises to 120°C, start feeding. After the carbon powder is fed from the silo 1 through the star-shaped discharge valve 2, the valve 2 is controlled to open at 4Hz, and enters the variable diameter feeding screw 3 (the diameter ratio is 0.5), and the compacted carbon powder enters the granulator 4. When there is powdered carbon black at the sampling port 5, open the granulation water ball valve 6. By constantly observing the granulation of carbon black at the sampling port 5, reasonably adjust the opening of the granulation water ball valve 6. When the particles are stable at the size of millet grains (about 0.5-2mm), fix the opening of the granulation water valve 6 at this time.

[0039] The granulated carbon black enters the high-temperature drum drying device 7, and the drum outlet temperature is controlled at 147±3°C to dry the granulated moisture in the carbon black to less than 2% (0.8%), thereby obtaining the finished granulated carbon black. The granulated carbon black enters the 20kg packaging machine 8 for packaging, and then enters the product warehouse for storage and sale.

[0040] The prepared granulated carbon black was tested for performance.

[0041]

[0042] It can be seen from the above results that the granulated carbon black obtained by the high-quality granulated carbon black preparation method of the present invention meets the use standards for rubber such as tires and conveyor belts in various indicators. Through the preparation method of the present invention, the pyrolysis carbon black can be packaged in various forms such as ton bags, half-ton bags, 20kg low-melting-point bags, 20kg woven bags, etc., and automatic feeding can be achieved, which perfectly solves the secondary pollution problem in the downstream application of pyrolysis carbon black and has revolutionary significance for the pyrolysis and recycling of waste tires.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. It should be understood by those skilled in the art that the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing granulated carbon black by pyrolysis of carbon slag, comprising the following steps: (1) Grinding the pyrolysis carbon residue to obtain carbon powder and pre-testing it: taking 100-300g of carbon powder to test the toluene transmittance and 45 micron sieve residue, the toluene transmittance is required to be greater than 60% and the 45 micron sieve residue is required to be less than 1000ppm; (2) The qualified carbon powder obtained in step (1) is loaded into a silo and fed into a granulator by a variable diameter screw feed method, wherein the variable diameter ratio is 0.4 to 0.8; (3) granulating the carbon powder and granulation water by uniform spraying and mixing in a granulator, wherein the particle size of the granulated carbon black is controlled between 0.5 and 2 mm, wherein the wall temperature of the granulator is kept at 120±5° C. before feeding, and after the temperature is stable, the valve opening of the carbon powder and the granulation water is controlled, and the two are mixed and fed in a ratio of 45±10wt% of the granulation water; (4) Drying the granulated moisture in the carbon black to less than 2 wt %, thereby obtaining a finished granulated carbon black that meets the use standards for tires or conveyor belt rubber, wherein the granulated carbon black enters a high-temperature drum drying device, and the drum outlet temperature is controlled between 140-155° C.

2. A pelletized carbon black prepared by the method of claim 1.

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