JP2005350292A - Fibrous porous carbonized product and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a fibrous porous carbonized product having excellent adsorptivity by using, as a raw material, a residue generated in a process for producing Japanese paper or the like. <P>SOLUTION: Pretreatments such as forming and drying are performed to a paper-making residue, and the resulting residue is heated and carbonized in a carbonization furnace to obtain a fibrous porous carbonized product which has a large surface area, and is uniformly carbonized, odorless and harmless. The firing temperature by heating is preferably 800-900°C. As the raw materials of paper-making residue, either one of wood pulp, bast fiber, plant fiber or waste paper recyclable trash, or their mixture can be used. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for obtaining a fibrous porous carbide having a good adsorptive power using a residue generated during the papermaking production process, and a fibrous porous carbide obtained thereby.

  Conventionally, a small part of the residue generated in the manufacturing process of Japanese paper or the like is reused as a raw material for papermaking. However, the amount of residue resulting from daily paper mill production activities is extremely large, and there is a need for effective treatment and utilization methods. One of the treatment methods is incineration using fossil fuels, but it also includes the risk of generating toxic substances such as dioxins, and immediate measures are desired from the viewpoint of environmental conservation. Yes.

  Therefore, in this technical field, it is possible to easily treat the papermaking liquor discarded by incineration without considering environmental pollution, and the carbides produced by the treatment are completely odorless and harmless. There is a keen desire for a method for treating waste.

  As a result of repeated research on the effective use of papermaking residue, which is an incineration waste, the present inventors consider that papermaking residue is a raw material containing high-quality cellulose, and carbonizes the residue. It has been found that, without generating toxic substances such as dioxin, it becomes an extremely porous carbide that doubles the activated carbon while maintaining the fibrous form.

  Moreover, in this carbonization treatment, it is extremely important that a carbon material having a high surface area is obtained without performing the activation treatment that is performed at the time of production of general activated carbon, and as it is a low-cost deodorizing and deodorizing agent as it is. Can be used.

  The method for producing the fibrous porous carbide of the present invention is to add water to a papermaking residue and knead and disperse, then remove the water to obtain a dry residue solid, and further, the dry residue solid is subjected to a low oxygen atmosphere. And / or heating and firing in an inert gas atmosphere. The fibrous porous carbide of the present invention is obtained by the above method.

  Commercially available wood-based activated carbon has about 99% by weight of carbon and low ash content of about 1%. In order to increase the specific surface area and pore volume, secondary treatment such as chemical activation treatment and gas activation treatment is performed after primary carbonization. On the other hand, the fibrous porous carbide of the present invention is high by only one-stage carbonization treatment, that is, carbonization treatment by heating and firing in a low oxygen atmosphere or an inert gas atmosphere without activation treatment. A fibrous carbide having a surface area can be obtained.

  As supported by the experimental data described below, the adsorption power of the porous activated carbide according to the present invention, such as ammonia and formaldehyde gas, shows a value more than double the adsorption power of commercially available Bincho charcoal, bamboo charcoal, etc. It can be said to be a porous activated carbide having a practical level of adsorption power. Moreover, since the activation process process currently performed at the time of activated carbon manufacture becomes unnecessary, energy saving can also be achieved.

  FIG. 1 is a flowchart of an operation for producing the fibrous porous carbide of the present invention. FIG. 2 is a schematic view of an operation for firing the fibrous porous carbide of the present invention.

  As shown in FIG. 1, the porous carbide of the present invention is a papermaking residue whose raw material is generated from a paper mill, but is not particularly limited as long as its main component is various pulps containing cellulose. For example, coniferous or hardwood wood pulp, bast fibers such as bamboo, three bases, cocoons and husks, plant fibers such as Manila pulp, waste paper resource waste such as newspapers and magazines, or mixtures thereof can be used.

  The porous carbide of the present invention is produced by firing a papermaking residue containing cellulose to have a carbon content of 90% by weight or more.

  The manufacturing method of the porous carbide | carbonized_material of this invention is demonstrated. First, water is appropriately added to the papermaking residue and kneaded and dispersed with a stirrer. The kneaded and dispersed papermaking residue is placed in, for example, a cylindrical container for molding. Then, it pressurizes and spin-dry | dehydrates and produces | generates a residue solid substance. In order to remove moisture from the solid residue from the container, it is dried by a dryer or the like to obtain a dry residue solid.

  Next, as shown in FIG. 2, the inside of the container is put in a container covered with a shielding plate such as metal and sealed. This sealed container is heated in a heating furnace in which the heating temperature can be freely changed, such as an electric furnace. The dried residue solids solidify and solids are formed. At this time, an inert gas (nitrogen, argon, etc.) is fed into the furnace to replace the inside of the furnace. Since the oxygen concentration in the container is low, oxygen contained in the dry residue solid is removed, and carbon in the component remains in the solid. Therefore, since a cavity is formed inside the solid material, porous carbide can be made.

  The heating temperature of the sealed container is preferably 800 ° C to 900 ° C. If the heating temperature is 1000 ° C. or higher, the porosity is lost, the number of bonding points between fibers increases, the gap decreases, the density increases, and the surface area decreases. The heating time is the time required for carbonization and varies depending on the size of the heating furnace, but is usually 10 hours or longer, and preferably 15 to 30 hours.

  As described above, the fibrous porous carbide of the present invention has a cavity formed inside the solid, and can adsorb malodorous substances and harmful substances such as carbon dioxide, ammonia and formaldehyde in the atmosphere. Moreover, the adsorption effect can be exhibited not only for the substances as described above but also for removing granulated substances such as soot and off-flavors generated from livestock farmers.

The fibrous porous carbide of the present invention can effectively utilize the papermaking residue that is disposed of by incineration as a raw material, and can obtain effects such as prevention of environmental pollution.

  3 L of water was added to 1500 g of Japanese papermaking residue, and kneaded and dispersed with a stirrer. The kneaded and dispersed papermaking residue was placed in a cylindrical container, and pressurized and dehydrated to produce a solid residue. Residual solids put out from the container were dried by a drier or the like to remove moisture, to obtain 1500 g of dry residual solids. This dry residue solid was put into a sealed container and carbonized at 850 ° C. for 24 hours in an electric furnace in which the heating temperature and heating time could be arbitrarily set, to obtain 80 g of fibrous porous carbide.

<Adsorption force comparison experiment>
1. Sample Preparation The fibrous porous carbide obtained in Example 1 was pulverized, sieved with a 50 μm sieve (325 mesh pass), and dried in a drier to give Sample A. A commercially available bamboo charcoal for deodorization was prepared as Comparative Sample B.

2. Test method For sample A, put 10 g of the same sample powder in a 2 L Tedlar bag, and then seal and seal the initial concentration of odorous substance. The gas concentration of the substance was measured and the change with time was examined. A test was conducted in the same manner for Comparative Sample B.

3. Results As shown in Table 1-3 and Figure 3-5.
(Table 1)

Ammonia concentration (ppm)
Elapsed time Sample A Sample B
0 20.0 20.0
1 13.9 15.3
2 9.80 13.0.
3 6.90 11.0
24 3.10 8.70
48 1.50 8.00
72 1.30 8.00
(Table 2)

Formaldehyde concentration (ppm)
Elapsed time Sample A Sample B
0 8.00 8.00
1 5.06 5.70
2 3.65 4.40
3 1.90 3.15
24 0.70 2.00
48 0.65 1.95
72 0.58 1.95
(Table 3)

Dimethylamine concentration (ppm)
Elapsed time Sample A Sample B
0 16.0 16.0
1 9.40 13.5
2 6.50 11.5
3 3.35 9.00
24 0.90 5.50
48 0.30 5.10
72 0.30 4.60

  As is apparent from these tables and figures, the fibrous porous carbide according to the present invention showed a significant deodorizing effect compared to bamboo charcoal for any odorous substance.

It is a flowchart of the operation | work which manufactures the fibrous porous carbide | carbonized_material of this invention. It is a general | schematic explanatory drawing of the operation | work which bakes the fibrous porous carbide | carbonized_material of this invention. In the graph in the adsorption test using ammonia as an odor substance, the vertical axis indicates the gas concentration ppm of the odor substance, the horizontal axis indicates the elapsed time, the black circle mark indicates fibrous porous carbide, and the black square mark indicates bamboo charcoal. In the graph of the adsorption test using formaldehyde as an odor substance, the vertical axis indicates the gas concentration ppm of the odor substance, the horizontal axis indicates the elapsed time, the black circle mark indicates fibrous porous carbide, and the black square mark indicates bamboo charcoal. In the graph of the adsorption power test using dimethylamine as an odor substance, the vertical axis indicates the gas concentration ppm of the odor substance, the horizontal axis indicates the elapsed time, the black circle mark indicates fibrous porous carbide, and the black square mark indicates bamboo charcoal.

Claims (5)

Water is added to the papermaking residue and kneaded and dispersed, and then the water is removed to form a dry residue solid, and this dry residue solid is heated and fired in a low oxygen atmosphere and / or an inert gas atmosphere. A method for producing a fibrous porous carbide. The method according to claim 1, wherein the heating and baking temperature is from 800C to 900C. The method according to claim 1 or 2, wherein the papermaking material is wood pulp, bast fiber, vegetable fiber, waste paper resource waste, or a mixture thereof. A fibrous porous carbide obtained by the method according to any one of claims 1 to 3. The fibrous porous carbide according to claim 4, wherein the carbon content is 90% by weight or more.