JPH04292409A - Production of activated carbon using waste tire as raw material - Google Patents

Abstract

PURPOSE:To provide a process for producing activated carbon from waste tire at a low cost with a simple process in high thermal efficiency and to enable the effective reutilization of waste tire and the utilization of a liquid by-product of the process as a fuel. CONSTITUTION:Waste tire is crushed to granules of about 1-3mm diameter. The granules are mixed with equal weight of powdery or liquid alkali metal salt such as sodium hydroxide and heated at 600-700 deg.C for 60-30min in a calcination oven in the presence of nitrogen gas. The carbonized product produced by the process is washed with distilled water to remove the alkali metal salt and dried. An activated carbon having a surface area of 450m<2>/g and a methylene blue absorption of 150ml/g can be produced by using the crushed granule and the alkali metal salt at a mixing ratio of 1:1.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a method for producing activated carbon used as a gas or vapor adsorbent, such as a deodorizing agent, a solution purifying agent, etc., and particularly relates to a method for producing activated carbon using waste tires as a raw material. .

0002

2. Description of the Related Art Currently, with the spread of automobiles, the amount of used waste tires, that is, waste tires, is rapidly increasing. Examples of methods for recycling waste tires include recovery of recycled tires, processed rubber products, fuel, tires for export, and pyrolysis oil. However, there is no known technology to proactively use waste tires as a raw material for activated carbon, and it is only known that the residue after burning as a fuel has adsorption ability.

0003

By the way, gas activation methods and chemical activation methods are conventionally known as methods for producing activated carbon using carbonaceous materials such as wood, fruit shells (coconut shells), and coal. The gas activation method involves sizing the carbonaceous material mentioned above,
After heating at 400 to 600°C, the obtained carbide is reacted with water vapor or carbon dioxide at 800 to 1000°C. In the chemical activation method, carbonaceous material is impregnated with zinc chloride solution and heated in an inert gas atmosphere. 500-7 in the calcining furnace in the presence of
After carbonizing by heating to 00°C, zinc is recovered using hydrochloric acid, followed by deashing, neutralization with alkali, washing with water, and drying.

[0004] Therefore, it has been considered to produce activated carbon from waste tires using the above-mentioned known activated carbon production method, but there are the following problems. First, in the gas activation method, the range of application of carbonaceous materials is limited, the manufacturing process is complicated, the thermal efficiency is low because activation is performed at a high temperature of 800 to 1000°C, and the activated carbon yield is low. This is the case.

On the other hand, the chemical activation method has problems such as the high cost of the chemicals and the necessity of a chemical recovery process. Thus, from the viewpoint of recycling waste tires, it is important to be able to produce activated carbon at low cost, but neither the gas activation method nor the chemical activation method is suitable for producing activated carbon using waste tires.

The present invention was made as a result of intensive research by the inventors in view of the above-mentioned problems of the prior art, and it is possible to produce activated carbon with a simple manufacturing process, low manufacturing cost, and a desired adsorption capacity. The present invention provides a method for producing activated carbon using waste tires as a raw material.

[0007]

[Means for Solving the Problems] The means of the present invention configured to solve the above-mentioned problems includes a pulverization step of forming waste tires into pulverized particles having a predetermined particle size or less, and an alkali-based method for applying alkali to the obtained pulverized particles. A mixing step in which a predetermined amount of metal salt is mixed and adhered, and the alkali metal salt-adhered pulverized particles obtained in the mixing step are heated to 600 to 700 g in the presence of an inert gas in a firing furnace.
The method consists of a heating step in which a carbide is generated by heating at a temperature of 00° C. for a predetermined period of time, and a washing and drying step in which the obtained carbide is washed to remove an alkali metal salt and dried.

[0008] It is preferable to mix an alkali metal salt in an amount equal to or more than the weight of the pulverized grains.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The particle size of the waste tire used in the present invention may vary depending on the activation conditions employed, but is preferably 1 mm or less. It is preferable that the amount of the alkali metal salt mixed with the pulverized grains is equal to or more than the same weight. A common method for mixing alkali metal salts is an impregnation method using a concentrated alkali metal salt solution. Furthermore,
In the heating process, the crushed grains are heated to 600-700°C,
Since the melting point of the alkali metal salt is within the range of 310° C. to 370° C., a solid or powdered alkali metal salt may be mixed and melted in a heating step so as to adhere to the surface of the pulverized particles.

Next, the heating temperature of the alkali metal salt-adhered pulverized particles is preferably in the range of 600 to 700°C. If the temperature is lower than 600°C, the activation effect of the alkali metal salt will be small;
This is because the performance of activated carbon is inferior. Meanwhile, increase the heating temperature to 70
If the temperature is higher than 0° C., the alkali metal salt will attack the carbon, resulting in a significant decrease in the activated carbon yield.

[0011] As the reaction method, various methods such as fixed bed, fluidized bed, and transport bed methods can be used, and for the reaction treatment, either continuous method or batch method can be used.

[0012] Furthermore, the heating time is such that the heating temperature is 650°C.
Appropriate time is approximately 60 minutes when the temperature is 700°C, and approximately 20 minutes when the temperature is 700°C.

[0013] The carbide obtained as a result of heating is washed with distilled water or the like to remove alkali metal salts, but at this time, the amount of water and washing time may be adjusted, or washing water to which acids have been added may be used. Depending on the use of activated carbon, its P
It is better to adjust H. The activated carbon after washing may be dried by either natural drying or forced drying using a dryer.

[0014] In the heating step in the method of the present invention,
Liquid products (tar) and gas can be obtained. The liquid product is extracted by an average of 40% based on the ground grains of the raw material. Its components are carbon = 83-85%, hydrogen = 9-11%,
It contains 0.2 to 0.5% sulfur and has a composition similar to that of so-called A heavy oil, so it can be fully used as a fuel.

On the other hand, the gas obtained in the heating process has a yield of 2
~4%, and its main components are methane and ethane.

[0016]

[Effects of the Invention] According to the method of the present invention, the following effects can be achieved. ■Disposal methods have become an issue,
Moreover, waste tires, which are expensive to dispose of, can be effectively reused. ■Compared to the gas activation method, the heating temperature is lower, so it has excellent thermal efficiency. Furthermore, when compared with the chemical activation method, since alkali metal salts are cheaper than zinc chloride, manufacturing costs can be lowered, and a chemical recovery process is not required, so a complicated manufacturing process is not required. (2) A high yield of 35-40% can be obtained based on the raw material. ■Liquid product can be used as fuel.

[0017]

[Examples] Examples of the present invention will be described in detail below.

Although sodium hydroxide among the alkali metal salts was used in this example, potassium hydroxide, for example, may also be used. First, a waste tire is crushed into crushed pieces of about 20 to 50 mm using a tire crusher, and at this time, the beat wires are separated using a magnet. The crushed pieces obtained by magnetically separating the beat wire are further crushed into crushed particles having a particle size of about 1 to 3 mm.

Next, 50 g of the pulverized grains were placed in a Teflon beaker, and 50 g of an equal weight of sodium hydroxide solution was added thereto and mixed to adhere the sodium hydroxide to the surface of the pulverized grains, and then dried at 110°C. let

Next, 10 g of crushed granules with sodium hydroxide attached
Weighed accurately on a stainless steel board, with a diameter of 50 mm,
It was placed in the center of a horizontal reaction tube with a length of 600 mm, and while nitrogen was flowing into the reaction tube at a flow rate of 100 ml/min, the temperature was raised from room temperature to 650 °C at a rate of 10 °C per minute. Heat for 1 hour, then cool to room temperature.

The carbonized product obtained as described above was washed with 5 liters of warm distilled water to remove sodium hydroxide and dried at 105° C. to produce activated carbon.

Table 1 shows other samples (a), (b), and (b) with different amounts of sodium hydroxide added regarding the composition of the product.
A comparison is shown with c). From this table, when the mixing ratio of crushed grains and sodium hydroxide is 1:1, the yield of carbide is 41.7
It can be seen that it is the highest at 3%.

[0023]

[Table 1]

Next, FIG. 1 shows the specific surface area and methylene blue adsorption capacity of the activated carbon according to this example for comparison samples (A) and (A).
(B) and (C) are shown together. Note that the surface area of activated carbon is -7
Carbon dioxide at 8°C was determined using the BET adsorption isotherm. Also, methylene blue adsorption capacity is JIS K1470.
It was measured by As is clear from Figure 1, when the mixing ratio of sodium hydroxide to crushed particles is 1:1, the surface area of activated carbon is 450 m2 /g, and the methylene blue adsorption capacity is 1.
50 ml/g (according to JIS K1470), which is more than double the value of comparative samples (a), (b), and (c).

Furthermore, FIG. 2 shows the yields of activated carbon, liquid product, and gas for each concentration of sodium hydroxide added. As can be seen from the figure, when the mixing ratio of sodium hydroxide to the pulverized particles is 1:1, the yield of activated carbon and gas is highest.

Furthermore, Table 2 shows the elemental analysis and average molecular weight of the liquid product obtained in the process of producing activated carbon.

[0027]

[Table 2]

According to Table 2, the composition of the liquid product is almost unaffected by the amount of sodium hydroxide mixed, and is 85% carbon, 11% hydrogen, and has an average molecular weight of 3,300. Also,
According to gas chromatography analysis, the liquid product contains small amounts of toluene and 0-xylene. The calorific value of this liquid product is 11,000 Kcal/kg
It is.

Next, Table 3 shows the components of the gas produced during the activated carbon manufacturing process.

[0030]

[Table 3]

As is clear from Table 3, the main components of the produced gas are methane and ethane, and these components increase as the amount of sodium hydroxide mixed increases.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the specific surface area and methylene blue adsorption capacity of activated carbon produced by the method of the example together with a comparative example.

FIG. 2 is a diagram showing the yields of activated carbon, liquid product, and gas according to the example method along with comparative examples.

Claims (2)

[Claims] Claim 1: A pulverizing step of forming a waste tire into pulverized particles having a predetermined particle size or less, a mixing step of mixing and adhering a predetermined amount of an alkali metal salt to the obtained pulverized particles, and a step of adhering a predetermined amount of an alkali metal salt to the obtained pulverized particles; A heating step in which the pulverized grains with alkali metal salts attached are heated in a firing furnace at a temperature of 600 to 700°C for a predetermined period of time in the presence of an inert gas to form a carbide, and the resulting carbide is washed to form an alkali metal salt. remove the
A method for producing activated carbon using waste tires as a raw material, which comprises a drying process and a drying process. 2. The method for producing activated carbon using waste tires as a raw material according to claim 1, wherein an equal weight of an alkali metal salt is mixed with the pulverized particles.