KR20100117954A - Activated carbon and the manufacturing method thereof - Google Patents

Abstract

PURPOSE: An activated carbon and a manufacturing method thereof are provided to increase productivity by using waste byproducts without a hardening carbonation process. CONSTITUTION: An activated carbon is made to a bio char obtained by the pyrolysis of agricultural byproducts. The agricultural byproducts are pyrolyzed and the pyrolyzed bio char is chemically activated. A rice straw char is mixed with basic solutions. The byproducts are firstly dried. The firstly dried mixture is put in a reactor and the temperature of the reactor is raised. The raised temperature is maintained. The basic solution is cleaned with acid solution. The remaining acid ions are secondly cleaned. The activated carbon is secondly dried.

Description

Activated Carbon and the Manufacturing Method Thereof}

The present invention relates to activated carbon and a method for producing activated carbon, and more particularly, to prepare activated carbon using bio Char.

Generally, activated carbon is widely used as a carbon selective catalyst reduction (CSCR) process, an adsorption tower, a water treatment material, and a sulfur oxide (SOx) treatment material.

In addition, the activated carbon is a material that is relatively inexpensive raw material price among the carbon source, that is, nut shell, wood, coal, lignin, coconut shell, rice bran, fruit seeds, and the like.

Activated charcoal is a material having a strong adsorption force that tries to fill the empty space due to the many fine holes generated when the cell wall burns by carbonization process after carbonization by burning the carbon source.

In addition, the activated carbon is manufactured by pulverizing a carbonized carbon source and then molding and activating a predetermined molded body, which must undergo a hard carbonization process before activation.

However, the hardening carbonization process requires a lot of energy through the dehydrator (~ 120 ℃), volatile organic material remover (~ 550 ℃), high temperature activator (~ 1000 ℃), the main cause of raising the production cost of activated carbon It would have been.

The present invention is to simplify the manufacturing process by utilizing the waste by-products to increase the productivity, and to provide a method for producing activated carbon and activated carbon at a low manufacturing cost.

This object of the present invention is solved by providing an activated carbon made of bio Char (pyro) by pyrolysis of agricultural by-products.

The bio Char (Char) is a straw straw pyrolyzed rice straw.

A pyrolysis process for pyrolyzing agricultural byproducts;

It is solved by providing a method for producing activated carbon including an activation process for activating biodegraded biochar through the pyrolysis process.

The pyrolysis process is to produce rice straw by pyrolysis of rice straw which is an agricultural by-product.

The activation process is activated by a chemical activation method.

Chemical activation method comprises the impregnation mixing step of mixing and mixing with rice straw (RC) using an impregnation method in a basic solution;

A first drying step of drying the mixed mixture through the impregnation mixing step;

A temperature raising step of putting the mixture dried in the first step into a reactor and raising the temperature in the reactor;

An isothermal step in which the temperature raised in the temperature rising step is maintained;

A first washing step of washing basic ions with an acidic solution in the mixture subjected to the isothermal step;

A second washing step of washing and removing the acidic ions remaining in the first washing step;

It includes a second drying step of drying the activated carbon prepared in the second washing step.

The basic solution uses potassium hydroxide (KOH) solution and the acidic solution uses hydrogen chloride (HCL) solution and distilled water in the second washing step.

The present invention has the effect of simplifying the manufacturing process by producing activated carbon without hardening carbonization process, and at the same time reducing the manufacturing cost and quality.

In addition, the present invention has the effect of reducing the production cost by using biomass pyrolysis 촤, which is a waste by-product treated after producing the oil and gas by pyrolysis of biomass, as an activated carbon carbon source, and the cost of treating waste by-products.

When described in detail with reference to the accompanying drawings a preferred embodiment of the present invention.

1 is an electron scanning micrograph of the rice straw (RC) used as the carbon source of the present invention, Figure 2 is an electron scanning micrograph of activated carbon (RCW) activated by the physical straw method of the rice straw of Figure 1, Figure 3 1 is a scanning micrograph of activated charcoal (RCK) activated by the chemical activity method of the straw char of FIG.

Figure 4 is a graph showing the results of the adsorption curve analysis, activated carbon (RCW) activated rice straw (RC) and rice straw by physical activity method, activated carbon (RCK) chemically activated rice straw (char) in nitrogen isothermal adsorption method Adsorption curve graph analyzed by.

Figure 5 is a graph showing the pore size distribution, activated carbon (RCW) activated rice straw (RC) and rice straw by physical activity method, activated carbon (RCK) chemically activated rice straw (char) by nitrogen adsorption desorption method The measured nitrogen desorption amount was analyzed by Barrett-Joyner-Halenda (BJH) method and pore size distribution was shown.

Hereinafter, the activated carbon of the present invention is produced by activating a bio-char (Char) by thermally decomposing any one of the carbon sources by using agricultural by-products such as wood chips, peanut shells, rice straw, animal manure and the like as a carbon source.

And it is preferably prepared by activating rice straw (RC) by thermally decomposing rice straw into a carbon source.

The rice straw is mass-produced in Korea and is inexpensive, and is suitable for application as a carbon source of activated carbon by containing a large amount of carbon after pyrolysis and containing a large amount of carbon.

The production method for producing the activated carbon is as follows.

Once the rice straw is pyrolyzed at 450 to 550 ° C. for 1 hour to 2 hours in an oxygen-free vacuum or inert gas atmosphere to undergo a pyrolysis process to produce rice straw.

In the pyrolysis process, the straw is filled in a sealed metal container in more detail, and then pyrolyzed at 500 ° C. for 1 hour while injecting nitrogen (N 2) into the metal container at 50 ml / min.

As described above, rice straw produces pyrolysis oil and pyrolysis gas through a pyrolysis process, and rice straw, which is a waste by-product after oil and gas production, is formed into pellets.

And the rice straw 되는 is made of activated carbon through an activation process.

The activation process includes a physical activation method and a chemical activation method, and is preferably activated by a chemical activation method.

In the embodiment of the present invention, activated carbon activated by rice straw (RC) by physical activation method is called first activated carbon (RCW), and activated carbon activated by chemical activation method is described as second activated carbon (RCK). .

Physical activation method for producing the first activated carbon (RCW) is a steam injection step of injecting rice straw 촤 into the reactor and injecting steam containing steam into the reactor;

A temperature raising step of raising the temperature in the reactor to a predetermined temperature by steam injection;

It includes an isothermal step that is maintained for a predetermined time at a constant temperature raised by the temperature increase step.

As an example of the present invention, a process of manufacturing first activated carbon (RCW) by a physical activation method will be described in detail as follows.

The first activated carbon (RCW) is put into a U-shaped reactor 5g of straw straw (RC), the temperature rising step of injecting nitrogen gas with a water content of 40% at 50ml / min and raising the temperature to 700 ℃ at 5 ℃ / min at room temperature And it is prepared through an isothermal step to maintain for 1 hour at 700 ℃ in the temperature increase step.

In addition, the chemical activation method for producing the second activated carbon (RCK) comprises an impregnation mixing step of mixing with a straw straw (RC) by using an impregnation method in a basic solution;

A first drying step of drying the mixed mixture through the impregnation mixing step;

A temperature raising step of putting the mixture dried in the first step into a reactor and raising the temperature in the reactor;

An isothermal step in which the temperature raised in the temperature rising step is maintained;

A first washing step of washing basic ions with an acidic solution in the mixture subjected to the isothermal step;

A second washing step of washing and removing the acidic ions remaining in the first washing step;

And a second drying step of drying the activated carbon prepared in the second washing step.

Hereinafter, a process of manufacturing second activated carbon (RCK) by the chemical activation method will be described in detail.

The basic solution uses potassium hydroxide (KOH) solution and the acidic solution uses hydrogen chloride (HCL) solution.

In the impregnation mixing step, 5 g of rice straw (RC) and potassium hydroxide solution were mixed in a 1: 1 (weight ratio: W / W) using an excess solution impregnation method, followed by mixing at 60 ° C. for 2 hours.

In addition, the first drying step is to dry the mixture passed through the impregnation mixing step to 110 ℃ in the oven for about one day.

The temperature raising step is to put the mixture passed through the first drying step into a U-shaped reactor, the nitrogen gas having a water content of 40% is injected at 50ml / min and heated up to 700 ℃ at 5 ℃ / min at room temperature.

The isothermal step is to maintain 1 hour at 700 ℃ heated in the temperature increase step.

The first washing step is to remove K + remaining in the mixture using 5 molar (M) hydrogen chloride (HCL) solution.

The second washing step is to remove Cl- using distilled water.

In addition, the second drying step is dried by heating the activated carbon from which Cl- removed to 110 ℃ for about one day.

When the first activated carbon (RCW) manufactured by the physical activation method, the second activated carbon (RCK) manufactured by the chemical activation method, compared with the unactivated rice straw RC (RC) as described above to explain the degree of activation of rice straw 하면 Same as

1 is an enlarged picture of the surface of the straw straw (RC) by 100,000 times with an electron scanning microscope, Figure 2 is a picture taken by expanding the surface of the first activated carbon (RCW) 100,000 times, Figure 3 is the agent 2 The surface of the activated carbon (RCK) is a picture taken by expanding the surface of 100,000 times.

As shown in Figures 1 to 3 it can be seen that small pores of about 50nm each formed on the surface of rice straw (RC), the first activated carbon (RCW), the second activated carbon (RCK).

The pore distribution is in the order RC <RCW <RCK. Through the process of slow pyrolysis, straw-shaped pores are formed in the projections, and these pores are more generated during the high temperature activation process, and the second activated carbon (RCK) manufactured by the chemical activation method is a physical activation method. Compared to the first activated carbon (RCW) manufactured it can be confirmed that it has a lot of pores.

In addition, the depth of bone and pores deep in the second activated carbon (RCK) can be observed, through which the second activated carbon (RCK) by the chemical activation method has a rugged surface structure, has many pores It can provide a lot of reaction space that can react when used as activated carbon.

4 shows adsorption curves of nitrogen of rice straw (RC), first activated carbon (RCW), and second activated carbon (RCK) at 77K.

Adsorption curves are divided into I, II, III, and IV according to the classification method of Brunauer, Deming, Deming and Teller (BDDT), and as shown in FIG. 4, straw straw (RC) and first activated carbon (RCW). ) And the second activated carbon (RCK) all show the same form as the activated carbon in which nitrogen is adsorbed at a low pressure close to p / po of zero.

This indicates that there are many micropore regions. In addition, when the amount of adsorption increased in the order of rice straw RC (RC) <first activated carbon (RCW) <second activated carbon (RCK), more fine pores were made when activating rice straw 촤 (RC) and physical activation method Compared with the chemical activation method, it can be seen that the micropores increase more.

In addition, an increase in the amount of adsorption in mesopores and micropore regions, which was not seen in rice straw (RC) and first activated carbon (RCW), can be seen in the second activated carbon (RCK).

In addition, the adsorption curves of the second activated carbon (RCK) have the form of I and IV, and the chemical activation method enables mesopores and micropore regions as well as a dramatic increase in micropores. It can be seen that the method of increasing the pore of.

It is very important in terms of smooth flow of reaction gas and expansion of working point, which have mesopores and micropores, many micropores, and a large specific surface area when applying activated carbon.

Meanwhile, FIG. 5 shows the nitrogen desorption amount measured by nitrogen adsorption and desorption of straw straw (RC), first activated carbon (RCW) and second activated carbon (RCK) at 77 K using Barrett-Joyner-Halenda (BJH) method. Interpretation and pore size distribution.

As shown in FIG. 5, the straw straw (RC), the first activated carbon (RCW), and the second activated carbon (RCK) were all selectively enlarged in pores of 3.7 nm, and in particular, a catalyst which activated 촤 physically and chemically. You can see that the pores of 3.7nm opened a lot.

Also, in case of rice straw (RC), small but selective pores were opened through the slow pyrolysis process, which means that volatile organic substances in rice straw are cracked and vaporized by heat during the pyrolysis process. Open pores as they exit the sample.

Since the pores of the same area of the first activated carbon (RCW) and the second activated carbon (RCK) are expanded, it is determined that more pores are opened through the high temperature activation process.

In addition, in the case of the second activated carbon (RCK), it can be observed that not only 3.7 nm pores but also large pores in the mesopore region and the micropore region are opened, which is chemical activation compared to the physical activation method. It can be seen from the adsorption curve as well as the desorption curve by the Barrett-Joyner-Halenda (BJH) method, which shows a wide pore distribution in the mesopore region and the micropore region.

On the other hand, Table 1 is a multi-molecular layer adsorption formula established by the BET equation (Brunauer, Emmett, Teller in 1938) the nitrogen adsorption amount of rice straw (RC), first activated carbon (RCW), second activated carbon (RCK) at 77K ), The BET-surface area, pore volume, and average pore size were measured based on.

In addition, since the analysis target is a carbon source made up of most carbons, CET is 100 or more, Correlation coefficient value is 0.9998 or more, and the p / po value is 0.05 ~ 0.35 in the section where the start point and the end point are captured and the BET drawing ( plot).

division BET-surface area
(m ² / g) Pore volume
(cm ³ / g) Average size of pores
(nm) Rice straw (RC) 139.5 0.092 2.642 Primary activated carbon (RCW) 363.0 0.164 1.809 Second activated carbon (RCK) 772.3 0.422 2.185

As shown in Table 1, the first activated carbon (RCW) and the second activated carbon (RCK), which are high-temperature activated carbons, have a larger specific surface area than the RC, which is rice straw, especially the second activated carbon (RCK) according to the chemical activation method is 772.3. It had a large specific surface area of m 2 / g.

This shows that the chemical activation method increases the specific surface area more than the physical activation method in the high temperature activation method.

In addition, the pore volume also has the largest specific surface area of the second activated carbon (RCK), and the average pore size of the straw straw (RC) has the highest pore distribution as can be seen in the BJH plot based on the adsorption curve and the desorption curve. The pores of the micropore region smaller than 3.7 nm showing a frequency are slightly open to 2.642 nm, and the average pore size of the first activated carbon (RCW) has more micropore regions during physical activation. It is 1.809 nm, which is smaller than 3.7 nm showing the pore distribution frequency. The average pore size of the second activated carbon (RCK) has many micropores and mesopores even during chemical activation. It is 2.185nm smaller than 3.7nm, which shows that the selective pores are open.

As described above, the present invention can confirm that it is more preferable to prepare by activating rice straw 으로 by the chemical activation method described above.

The present invention is to reduce the production cost of activated carbon by thermally decomposing biomass to produce biomass oil and biomass gas utilized as renewable energy, and then use biomass pyrolysis 인, that is, rice straw 으로 as activated carbon carbon source, In other words, the biomass can be recycled.

The present invention is not limited to the above-described embodiments, and various changes can be made without departing from the gist of the present invention, which is understood to be included in the configuration of the present invention.

1 is an electron scanning micrograph of rice straw (RC) used as a carbon source of the present invention

FIG. 2 is an electron scanning micrograph of activated carbon (RCW) obtained by physically activating the rice straw of FIG.

FIG. 3 is a scanning micrograph of activated carbon (RCK) obtained by chemically activating rice straw char of FIG. 1.

4 is a graph showing the results of adsorption curve analysis

5 is a graph showing the pore size distribution

Claims (7)

Activated carbon, characterized in that produced by bio-char (pyrolysis) of agricultural by-products. The method according to claim 2, The bio char (Char) is activated charcoal, characterized in that the straw straw pyrolysis of rice straw. A pyrolysis process for pyrolyzing agricultural byproducts; Activated carbon production method characterized in that it comprises an activation process for activating the bio-char (py) pyrolyzed through the pyrolysis process. The method according to claim 3, The pyrolysis process is a method of producing activated carbon, characterized in that to produce rice straw by pyrolysis of rice straw which is an agricultural by-product. The method according to claim 3, The activation process is activated carbon production method characterized in that the activation by a chemical activation method. The method according to claim 5, Chemical activation method comprises the impregnation mixing step of mixing and mixing with rice straw (RC) using an impregnation method in a basic solution; A first drying step of drying the mixed mixture through the impregnation mixing step; A temperature raising step of putting the mixture dried in the first step into a reactor and raising the temperature in the reactor; An isothermal step in which the temperature raised in the temperature rising step is maintained; A first washing step of washing basic ions with an acidic solution in the mixture subjected to the isothermal step; A second washing step of washing and removing the acidic ions remaining in the first washing step; Activated carbon manufacturing method comprising a second drying step of drying the activated carbon prepared in the second washing step. The method according to claim 6, The basic solution is a potassium hydroxide (KOH) solution, the acidic solution is a hydrogen chloride (HCL) solution, the method of producing activated carbon, characterized in that using distilled water in the second washing step.

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