JP5203576B2 - Paper charcoal and method for producing the same - Google Patents

Description

  The present invention relates to paper charcoal obtained by carbonizing waste paper and the like and a method for producing the same.

  Waste paper has been used mainly as recycled paper. However, in the recycling of used paper, pulp fibers deteriorate and strength decreases in the disaggregation and foreign matter removal step of loosening the paper fibers. For this reason, it is technically difficult to increase the percentage of waste paper mixed in paper products. For this reason, as another recycling method of used paper, carbonization of used paper to produce activated carbon or paper charcoal is performed (for example, see Patent Documents 1 and 2).

On the other hand, in recent years, attempts have been made to decompose and recycle organic waste by hydrothermal treatment as a method for treating and reusing organic waste. However, it is known that when organic matter is pyrolyzed, a high viscosity and tar content containing harmful substances is generated. The tar content causes problems such as blockage of piping, contamination into products, and contamination due to discharge to the environment. For this reason, it is required to effectively separate and recover the tar content in the presence of water. In this specification, the tar content is a generic name for black or brown viscous oily substances generated by thermal decomposition of organic matter. Coal tar obtained by dry distillation of coal, distillation of petroleum and its thermal decomposition products It includes petroleum tar, which is a generic term for residues, and wooden tar, which is one of liquid products obtained by dry distillation of wood.
JP 200645002 A JP-A-11-171524

However, papers charcoal described in Patent Document 1, in order to eliminate the residual tar is carbonized at 650~800 ℃ (923~1073K). Since heating temperature is raised, there exists a problem that cost becomes high. Also, papers charcoal described in Patent Document 1, formaldehyde, toluene, a relatively small molecular weight substances such as ammonia merely look adsorbability in a gas.

  In addition, the activated carbon described in Patent Document 2 is made by compacting waste paper into pieces and mixing with a thermosetting resin. For this reason, it is necessary to perform the consolidation process.

  Moreover, neither document describes at all about the effective separation and recovery of tar content.

  That is, the present invention has been made in view of the above problems, and an object of the present invention is to provide a paper charcoal that can effectively separate and recover a tar content and a method for producing paper charcoal under mild conditions.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have a function that cannot be obtained with conventional paper charcoal by carbonizing the used paper by water-wetting and molding it using superheated steam. We found that paper charcoal can be obtained. That is, the present invention is as follows.

Paper charcoal of the present invention is a paper charcoal carbonized paper with superheated steam, the cumulative pore volume of pores having a pore diameter of 10 to 10 ³ nm ^is is 3000mm ³ / g~4000mm 3 / g .

  The paper charcoal can be used as a tar remover.

  Such paper charcoal can be produced by a paper charcoal production method including a step of forming paper by wetting paper with water and a step of carbonizing the dried paper in superheated steam.

  INDUSTRIAL APPLICABILITY The present invention can provide paper charcoal that can effectively separate and recover the tar content by carbonizing the paper that has been wetted, shaped, and dried with superheated steam.

  The present invention is described in detail below.

[material]
Examples of the raw material for producing the paper charcoal of the present invention include paper such as corrugated paper, newspapers and magazines, office paper, catalogs and leaflets. These papers are collected as waste. Among these papers, preferred are papers that are easily wetted by water and easy to form, such as newspapers and magazines.

[Production method]
The papers may be used as they are, but in order to facilitate the forming, papers that have been cut into an appropriate size in advance may be used. Water is added to the paper to wet the paper. The amount of water to be added is sufficient as long as paper can be formed, and is appropriately adjusted according to the type of paper, the degree of dryness, and the like. Next, wet papers are formed. The molding may be performed using a known molding means. The shape can also be appropriately selected according to the purpose of use, such as a sphere or a square. Next, the formed papers may be dried. The drying conditions are appropriately selected according to the water content.

  The formed and dried paper is carbonized in superheated steam. The carbonization apparatus may be a known carbonization apparatus, and may be a batch type or a continuous type. For example, a carbonization apparatus as shown in FIG. 1 is used. The carbonization apparatus of FIG. 1 is an example of a batch-type carbonization apparatus, a water tank that stores water, a metering pump that supplies a certain amount of water to a carbonization furnace, and an electricity that vaporizes water and generates superheated steam. A carbonization furnace including a furnace, a thermometer for measuring the temperature in the carbonization furnace, connected to the carbonization furnace via a pipe line, and cooling excess steam generated in the carbonization furnace as the carbonization process proceeds, And a surplus water vapor treatment means for discharging the contained gas component while collecting water.

  As the carbonization conditions, conditions under which carbonization does not proceed extremely are selected. For example, carbonization is performed at 773K for about 1 hour.

[Paper charcoal]
The paper charcoal of the present invention is carbonized in a state in which the cellulose fibers of the paper raw material are folded at appropriate intervals. Further, in the paper charcoal present invention, the cumulative pore volume of pores having a pore diameter of 10 to 10 ³ nm ^is a 3000mm ³ / g~4000mm 3 / g.

  When tar is adsorbed using such paper charcoal of the present invention, 2 to 4 kg / kg-adsorbent and a very large amount of tar are adsorbed. In the tar / water mixed system, when the paper charcoal of the present invention is used, water is hardly adsorbed and only tar is adsorbed. That is, the paper charcoal of the present invention effectively separates and recovers the tar content in the presence of water. Therefore, the paper charcoal of the present invention is useful for hydrothermal treatment of organic waste, recovery of heavy oil spilled in the ocean, and the like. In particular, when hydrothermal treatment of organic waste using subcritical water is performed, when the paper charcoal of the present invention is placed in a reaction apparatus and treated, tar content generated from the paper charcoal is effectively removed. As a result, processing that does not cause problems such as blockage of piping, mixing into products, and discharge to the environment can be performed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to this Example.

[Manufacture of paper charcoal]
Weekly magazines and newspapers were cut into pieces of about 5 × 10 cm, and ultrapure water was added to moisten them. Wet papers were rolled up by hand and formed into a spherical shape with a diameter of about 1 cm. The formed papers were dried at 333K for 3 days. The dried papers were carbonized using the batch type carbonization apparatus shown in FIG. Carbonization was performed by raising the temperature from 423 K to the target carbonization temperature of 773 K in a heating time of 30 minutes and then maintaining this temperature for 60 minutes. After the carbonization treatment, the temperature was lowered in about 30 minutes. The flow rate of superheated steam was 1 g / min. The inflow of superheated steam was operated using 423K, which is considered to start thermal decomposition, as a start point and an end point. By this treatment, paper charcoal (weekly magazine) and paper charcoal (newspaper) as examples of the present invention were obtained.

[sample]
As a sample, in addition to the paper charcoal (weekly magazine) and paper charcoal (newspaper) obtained above, as comparative examples, Isolite CG4 (manufactured by Isolite Kogyo Co., Ltd.), Yashigara activated carbon GA4-8 (manufactured by Cataler Co., Ltd.) , Charcoal charcoal (hinoki) made with superheated steam of 623K and 723K using a bamboo charcoal (commercially available product) and rotary kiln type carbonizer (Johnson Boiler Co., Ltd.) (hereinafter referred to as "charcoal 623K" and "charcoal 723K") ), Paper charcoal (Johnson Boiler Co., Ltd.) was used.

[Tar content]
As the tar content, wood tar content (manufactured by Daiko Pharmaceutical Co., Ltd.) was used. In addition, the low boiling point component below 373K is removed from this tar content by distillation operation.

[Physical properties, elemental analysis]
(Physical property value)
Table 1 shows the physical property values of Isolite CG4.

(Elemental analysis)
Fully automatic elemental composition of wood tar, charcoal 623K, charcoal 723K, coconut charcoal activated carbon, bamboo charcoal, paper charcoal (manufactured by Johnson Boiler), paper charcoal (weekly magazine), paper charcoal (newspaper), weekly magazine, newspaper This was performed using an elemental analyzer (PE2400 Series II CHNS / O, manufactured by Perkin Elmer Co., Ltd.). The analysis conditions are: measurement method: static combustion, frontal chromatography, high-sensitivity thermal conductivity detector (TCD), combustion temperature: 1248 K, reduction temperature: 773 K, carrier gas: helium, sample weight: 1.5-2. 0 (mg), analysis time: 8 minutes. The results are shown in Tables 2 and 3.

  In this table, other than carbon, hydrogen, and nitrogen is expressed as Other. Nitrogen is not included in this table because it is 0.5 wt% or less in all results. Moreover, it was thought that there was not much ash contained in carbide. Therefore, Other was regarded as the ratio of oxygen element.

  From Table 2, it can be seen that the wood tar content has a higher ratio of Other. This was thought to be due to the large number of oxygen atoms remaining in the lignin, the main causative substance of wood tar. In all samples used for elemental analysis, 70% or more is composed of carbon. There was no significant difference in the elemental composition of the samples. Coconut charcoal activated carbon and paper charcoal (manufactured by Johnson Boiler Co., Ltd.) were found to have a high carbon element ratio and carbonization proceeded compared to other samples.

Table 3 is a table showing the element residual ratio of the carbide calculated from the yield before and after carbonization of paper charcoal, and the elemental analysis results. The following formula was used for the calculation.
(Element residual ratio) [wt%] = (Carbide weight × Carbide element ratio) / (Raw material weight × Raw material element ratio)
As is apparent from Table 2, the elemental compositions of the weekly magazine / newspaper before carbonization, the paper charcoal after carbonization (weekly magazine), and the paper charcoal (newspaper) are almost equal. This was thought to be due to the fact that the raw material of weekly magazines and newspapers is wood fibers mainly composed of cellulose containing lignin. Further, as apparent from Table 3, since the carbonization conditions are the same, there was no significant difference between the weekly magazine and the newspaper.

[Observation of macro structure]
Isolite CG4, coconut husk activated carbon, charcoal 623K, charcoal 723K, bamboo charcoal, paper charcoal (manufactured by Johnson Boiler Co., Ltd.), paper charcoal (weekly magazine), paper charcoal (newspaper), weekly magazine, newspaper macro structure, JSM-6700 This was observed using a scanning field emission electron microscope (manufactured by JEOL Datum Co., Ltd., manufactured by Nippon Hitech Co., Ltd.). The results are shown in FIGS.

  From FIG. 2, it can be seen that Isolite CG4 has innumerable small holes on the surface. From FIG. 3, it can be confirmed that coconut husk activated carbon has no large cracks on the surface and small pores are open. 4 and 5, it can be seen that both the charcoal 623K and the charcoal 723K have large cracks on the surfaces and have pores. It can also be seen that the surface destruction of the charcoal 723K is more advanced than that of the charcoal 623K. FIG. 6 shows that bamboo charcoal is similar to the surface structure of coconut shell activated carbon and has small pores. 7, 8, and 9, it can be seen that in paper charcoal, the folded fibers have a layered structure. This is because, in the macro structure of the weekly magazine of FIG. 10 and newspaper, the constituent materials that were buried between the folded cellulose fibers were decomposed and gasified during the carbonization process, and the spaces between the remaining fibers became voids. Conceivable. As is clear from FIGS. 7, 8, and 9, the interval between fibers of paper charcoal (Johnson Boiler Co., Ltd.) is smaller than that of paper charcoal (weekly magazine) and paper charcoal (newspaper). This was thought to be because the paper charcoal (Johnson Boiler Co., Ltd.) was physically and strongly compressed before carbonization.

[Pore size distribution]
Using a mercury porosimeter (Pascal 140, Pascal 240, manufactured by Amco Corporation), Isolite CG4, coconut shell activated carbon, charcoal 623K, charcoal 723K, bamboo charcoal, paper charcoal (manufactured by Johnson Boiler Co., Ltd.), paper charcoal (weekly magazine), paper The pore diameter of charcoal (newspaper) was measured. First, using Pascal 140, mercury was injected into the sample container under vacuum, and then the process of returning gradually from the reduced pressure state to the atmospheric pressure (macropore measurement) was performed. Next, the sample container was replaced with Pascal 240 and pressurized with a hydraulic pump, and the mesopore region was measured. The pore radius was determined using the following equation.
Approximate expression of pore radius and pressure: R = 7.5 im / P
R: radius (nm), P: pressure (kg / cm ³ )
FIG. 11 and FIG. 12 show the results of comparison of cumulative pore volume and pore volume distribution in each sample obtained from the measurement of pore diameter.

From FIG. 11, it can be seen that the charcoal 623K, charcoal 723K, paper charcoal (weekly magazine), and paper charcoal (newspaper) have developed cumulative pore volumes compared to other samples.

  From FIG. 12, bamboo charcoal has mesopores, charcoal 623K, charcoal 723K, Isolite CG4, paper charcoal (manufactured by Johnson Boiler Co., Ltd.), paper charcoal (weekly magazine), and paper charcoal (newspaper) having a pore diameter of 100 nm to 100,000 nm ( It can be seen that macropores in the range of 0.1 μm to 100 μm have developed. Further, no significant development of mesopores and macropores was found in coconut shell activated carbon.

  Paper charcoal (manufactured by Johnson Boiler Co., Ltd.), paper charcoal (weekly magazine), and paper charcoal (newspaper) have developed macro pores in the same range, but paper charcoal (manufactured by Johnson Boiler Co., Ltd.) The pore volume was smaller than that of paper charcoal (weekly magazine) and paper charcoal (newspaper).

[Tar adsorption evaluation]
Samples (Isolite CG4, coconut husk activated carbon, charcoal 623K, charcoal 723K, bamboo charcoal, paper charcoal (manufactured by Johnson Boiler Co., Ltd.)), paper, infused with a sufficient amount of wood tar into a 15 mm diameter x 105 mm test tube Charcoal (weekly magazine) and paper charcoal (newspaper)). After elapse of a predetermined time (1 to 120 minutes), the sample was taken out, the wood tar content adhering to the surface was removed, and the sample was placed in a weighed sample bottle and the mass was measured.
Moreover, in order to investigate water absorption capability, the same experiment was conducted using ultrapure water.
The results are shown in FIGS.

  FIG. 13 is a diagram showing the change over time in the amount of tar adsorbed by each sample. From FIG. 13, paper charcoal (weekly magazine) showed the highest performance. Tar adsorption of paper charcoal (weekly magazine) was about 5 times that of Isolite CG4. It was also found that the tar adsorption amount of paper charcoal (newspaper) was superior to other samples. Charcoal 623K, charcoal 723K, bamboo charcoal, paper charcoal (manufactured by Johnson Boiler Co., Ltd.), paper charcoal (weekly magazine), and paper charcoal (newspaper) are compared. In the case of paper charcoal, the range of pore diameters of each is almost the same, but the paper charcoal (weekly magazine) and paper charcoal (newspaper) of the present invention having a large cumulative pore volume have a larger amount of tar adsorption. In addition, the paper charcoal (weekly magazine) and paper charcoal (newspaper) of the present invention mainly composed of wood fibers adsorb more tar content than charcoal having a larger cumulative pore volume. In paper charcoal, it is thought that the fibers are folded to form a network structure. Next, when bamboo charcoal and paper charcoal (produced by Johnson Boiler Co., Ltd.) having the same cumulative pore volume and different pore diameter ranges are compared, the adsorption of tar has a diameter of 100 nm or more. Pore seems to be affected.

  FIGS. 14 to 19 compare the amount of adsorbed water and the tar content of Isolite CG4, charcoal 623K, charcoal 723K, paper charcoal (Johnson Boiler Co., Ltd.), paper charcoal (weekly magazine), and paper charcoal (newspaper). It is a graph. FIG. 14 shows that the adsorption of tar is not so fast, but absorbs water instantaneously. 15 and 16 that charcoal absorbs the same amount of water as charcoal. 17-19, paper charcoal adsorb | sucks a tar part, but it turns out that water hardly absorbs.

[Evaluation of tar adsorption in the presence of water]
A 10 × 10 ⁻⁶ m ³ conical beaker was charged with 50 g of ultrapure water, 2.0 g of water, and 2.0 g of wood tar, and stirred uniformly with a magnetic stirrer, and then each sample (Isolite CG4, coconut shell activated carbon, charcoal) 623K, charcoal 723K, bamboo charcoal, paper charcoal (manufactured by Johnson Boiler Co., Ltd.), paper charcoal (weekly magazine), and paper charcoal (newspaper) 2.0 g are charged and stirred. After elapse of a predetermined time (3 to 30 minutes), the sample was taken out, put into a weighed sample bottle, dried at 333 K for 3 days, and then mass was measured. The adsorption amount of wood tar was calculated from the difference in mass before and after the experiment, and the change with time was measured. Moreover, the mass of the sample before drying was measured, and the difference in mass before and after drying was taken as the mass of absorbed ultrapure water. The adsorption experiment was performed at 298K.

FIG. 20 shows the change over time of the liquid phase using the paper charcoal (weekly magazine) of the present invention. As can be seen from FIG. 20, when 30 minutes have elapsed, the oily wood tar is almost absorbed and is not present in the aqueous phase .

  22 to 25 are graphs comparing the amount of adsorbed tar and the amount of water absorbed by Isolite CG4, charcoal 623K, charcoal 723K, and paper charcoal (Johnson Boiler Co., Ltd.). From FIG. 22, it can be seen that Isolite CG4 has absorbed almost the same amount of water as that of FIG. 14, but the wood tar content is not adsorbed at all. This is thought to be because the adsorption of the wood tar is hindered by the absorbed water. 23 to 25, it is understood that the amount of water absorbed by the charcoal 623K, the charcoal 723K, and the paper charcoal (Johnson Boiler Co., Ltd.) decreases as the amount of adsorption of the wood tar increases. This is considered that water was pushed out by the adsorbed wood tar. Paper charcoal (Johnson Boiler Co., Ltd.) absorbs more water than the tar adsorption test. This was thought to be because the surface that had been hydrophobic was covered with the adsorbed water and lost its hydrophobicity.

[Analysis of wood tar content]
The wood tar component before adsorption and the wood tar content adsorbed on each sample in the tar adsorption experiment were analyzed and compared with a gas chromatograph mass spectrometer (GCMS-QP5050, manufactured by Shimadzu Corporation). DB-WAX (J & W SCIENTIFIC) having a length of 30 m and an inner diameter of 0.25 mm was used as an analysis column. The analysis conditions are shown in the table below.

FIG. 26 shows the results of GC-MS analysis of the wood tar, and Table 5 shows the names and chemical formulas of substances with significant peaks.

  26 and Table 5, it can be seen that the wood tar contains various organic compounds having a large molecular weight. Moreover, when the wood tar content adsorbed by each sample was extracted with acetone and analyzed in the same manner as the wood tar content, the same peak as the wood tar content was obtained. From this, it was found that each sample adsorbs not the specific component but the wood tar itself.

[Paper charcoal residual tar content]
Paper charcoal (weekly magazine) and paper charcoal (newspaper) of the present invention were extracted with acetone to check whether tar content remained in the paper charcoal during paper charcoal production. Since the tar content was not recovered at all in acetone, it was found that no tar content remained in the paper charcoal (weekly magazine) and paper charcoal (newspaper) of the present invention.

FIG. 1 is a diagram showing an example of a carbonizing apparatus for producing paper charcoal according to the present invention. FIG. 2 is a scanning electron micrograph of the surface of Isolite CG4. FIG. 3 is a scanning electron micrograph of the surface of coconut shell activated carbon. FIG. 4 is a scanning electron micrograph of the surface of charcoal 623K. FIG. 5 is a scanning electron micrograph of the surface of charcoal 723K. FIG. 6 is a scanning electron micrograph of the bamboo charcoal surface. FIG. 7 is a scanning electron micrograph of the surface of paper charcoal (manufactured by Johnson Boiler Co., Ltd.). FIG. 8 is a scanning electron micrograph of the surface of paper charcoal (weekly magazine). FIG. 9 is a scanning electron micrograph of the surface of paper charcoal (newspaper). FIG. 10 is a scanning electron micrograph of the surface of a weekly magazine / newspaper. FIG. 11 is a diagram comparing the cumulative pore volume in each sample. FIG. 12 is a diagram comparing the pore volume distribution in each sample. FIG. 13 is a diagram showing the change over time in the amount of tar adsorbed by each sample. FIG. 14 is a graph comparing the tar content of Isolite CG4 and the amount of water adsorbed. FIG. 15 is a graph comparing the tar content of charcoal 623K and the amount of water adsorbed. FIG. 16 is a graph comparing the tar content of charcoal 723K and the amount of water adsorbed. FIG. 17 is a graph comparing the tar content of paper charcoal (manufactured by Johnson Boiler Co., Ltd.) and the amount of water adsorbed. FIG. 18 is a graph comparing the tar content of paper charcoal (weekly magazine) and the amount of water adsorbed. FIG. 19 is a graph comparing the tar content of paper charcoal (newspaper) and the amount of water adsorbed. FIG. 20 is a graph showing the change over time of the liquid phase using the paper charcoal (weekly magazine) of the present invention. FIG. 21 is a graph comparing the amount of adsorption of tar and the amount of water absorbed by Isolite CG4 . FIG. 22 is a graph comparing the amount of tar adsorbed by charcoal 623K and the amount of water absorbed . FIG. 23 is a graph comparing the amount of tar adsorbed by charcoal 723K and the amount of water absorbed . FIG. 24 is a graph comparing the amount of adsorbed tar and the amount of water absorbed by paper charcoal (Johnson Boiler Co., Ltd.) . FIG. 25 is a diagram showing a GC-MS analysis result of wood tar .

Claims (3)

A paper charcoal carbonized paper with superheated steam, the pore volume distribution of pore size 10 ⁴ n m has a pore is 300 to 400 mm ³ / g, pore size 10 ³ n m or less under Paper charcoal having no pores having a pore volume distribution of 200 mm ³ / g or more.   The paper charcoal according to claim 1, which is used as a tar removing agent. Moistening paper with water and forming without compression;
Including a step of carbonizing the dried paper in superheated steam, having a pore volume distribution with a pore size of 10 ⁴ nm of 300 to 400 mm ³ / g, and having a pore size of 10 ³ nm or less The manufacturing method of the paper charcoal which does not have a pore whose lower pore volume distribution is 200 mm < ³ > / g or more.