JP5101096B2 - Long-term storage method of wood - Google Patents

Description

  The present invention relates to a method of performing measures that contribute to the prevention of global warming by carbonizing charcoal, bamboo charcoal, or organic waste and storing it on an abandoned mine or the bottom of a freshwater lake for an extremely long period of time.

In recent years, afforestation projects have attracted attention as an effective measure against global warming. In afforestation as a measure against global warming, it is necessary to formulate an afforestation project plan that maximizes the amount of carbon stored in the tree as it grows. It is important to identify well. For this reason, it is necessary to accurately grasp the current amount of carbon stock in the afforestation candidate site, and to determine whether or not to plant the afforestation candidate site based on this carbon stock amount.
Collection of research results on new uses of charcoal and charcoal liquor (Wood carbonization component multi-use technology research association) (1990) Terminal Report on Carbon Fixing Forest Management Project in Indonesia; JICA (2005) Global Forest Resources Assessment 2000; Main Report, FAO (2001) "IPCC Third Assessment Report" (IPCC 2001) Forest Products 2003 (FAO) "Forest and Forestry Basic Plan" (Forestry Agency 2001) "Forest and Forestry White Paper (2004)"

  By the way, carbon dioxide fixation in trees can be absorbed and fixed in units of several decades. However, in the case of storage for 100 years, uncertainties such as logging and fires may occur, and carbon can be stably supplied over a long period of time. It may be difficult to fix. In addition, forests that have passed for a long time have deteriorated their ability to absorb carbon dioxide due to the aging of trees. If you use aging trees that have been cut down for construction, such as by using them as building materials, they may eventually be incinerated when they become waste. There is a problem of being discharged again into the atmosphere.

  This invention is made | formed in view of such a situation, and it aims at providing the long-term storage method of the timber which can preserve | save a timber stably for a long term.

The present invention is a method for long-term preservation of timber , which is obtained by carbonizing timber obtained by cutting a forest tree that has passed a predetermined period of time after planting , or waste wood so that the specific gravity exceeds 1, and making the depth easy to recover. The carbonized wood is preserved by submerging it in the water of a lake or sea that it has, and the preserved carbonized wood is taken out from the water and used as fuel as necessary.

  The present invention is characterized in that the carbonized wood is deposited in water in a container using a material that can withstand long-term storage.

  The present invention is characterized in that the container reuses a material that emits a hazardous substance at the time of incineration.

  According to the present invention, since the wood is stored by carbonizing the wood and submerging it in water, it becomes possible to store the carbon fixed in the tree for a long period of time, thereby enhancing the effect of preventing global warming. In addition, it is possible to purify water (lake water and seawater) using the charcoal adsorption capacity. Moreover, since the wood is carbonized so that the specific gravity exceeds 1, it can be easily submerged in water in the state of charcoal. In addition, the carbonized wood is placed in a container using a material that can withstand long-term storage and is deposited in water, so that storage management of submerged charcoal can be easily performed. Moreover, since the container which puts charcoal reused the material which emits a harmful substance at the time of incineration disposal, it becomes possible to use the material effectively without generating a dioxin-type harmful substance at the time of incineration disposal. In addition, since the carbonized wood is submerged in a lake with a depth that allows easy recovery, it can be easily taken out and reused when the fuel is depleted in the future.

Hereinafter, a long-term storage method for wood according to an embodiment of the present invention will be described.
<Preservation form of wood>
Carbonize the wood and store it as charcoal. Charcoal, including bamboo charcoal, has historically been considered to be preserved for a very long time, and has been excavated in numerous ruins so far, and the preservation of it has been obvious for several hundred to 1,000 years. It is suitable for stable long-term storage. As the timber to be carbonized, timber obtained by cutting a tree of a forest that has passed a predetermined period after planting, or waste material is used. Since aged trees have a reduced carbon dioxide absorption capacity, it is desirable that they be actively cut and carbonized. In the forest after felling, the capacity to absorb carbon dioxide can be increased by replanting. In addition, the waste materials that are used for building materials and the like are actively carbonized, and the waste materials are incinerated to prevent carbon from being released again into the atmosphere. In particular, there are limited places where trees can be planted, but if you manage the age of the already planted forest, cut trees with reduced carbon dioxide absorption capacity into charcoal, and start a new plantation, it will already be a forest. It is possible to maintain the carbon dioxide absorption capacity even in the place where

<Storage location>
For storage in air, an abandoned mine can be used. In this case, protection from fire is an issue, but application of fire prevention technology such as a sprinkler is easy. However, considering the equipment costs and the risk of fire in the unlikely event, storage in water is considered the most appropriate. Since underwater storage requires a large amount of storage over a long period of time, which will be described later, it is promising to deposit on the bottom of a large freshwater lake such as Lake Biwa or the seabed. In addition, it is desirable to select the depth of the lake or the seabed to be easily deposited so that the charcoal can be easily taken out when the lake bottom or the seabed is deposited.

<How to save>
When storing in water, place charcoal in a container or bag made of recycled PVC (vinyl chloride resin) or other material that can withstand long-term storage. The reuse of PVC products is also significant because of the significance of reducing dioxin-based hazardous substances generated during incineration. Moreover, since the specific gravity of charcoal changes with the manufacturing methods of charcoal, it is desirable to use charcoal with a specific gravity exceeding 1. However, the advantage that wood can be stored for a long time even if the specific gravity is less than 1 does not change, so in the case of such charcoal, put it in a PVC container, put a weight and submerge it in water. . When a weight is attached, the storage location on the lake bottom or the sea bottom does not change, and the storage can be stably performed.

<Physical properties of charcoal>
Charcoal varies in yield and properties depending on the firing temperature. The characteristics for each firing temperature are shown in FIG. In FIG. 1, the charcoal yield is charcoal weight / pre-carbonized wood weight. Although these are laboratory test results, when carbonizing by self-combustion in an actual charcoal kiln or the like, it is said that the firing temperature is 400 to 1000 ° C., the charcoal yield is empirically 20%, and the carbon content is about 85 to 90%. In a survey using tropical wood conducted in the JICA project in Indonesia, the charcoal production method using a drum can produced a charcoal yield of 23.6%, a carbon content of 86.3%, and an on-site manufacturing cost of 76.3 US $ / Ton (= 9,000 yen / ton). That is, it is calculated that charcoal can be taken from 1 m ^{3 of} wood (dry weight 0.5 ton) to about 0.1 ton (20% of dry wood weight). This amount is CO _{2 of} 0.1 ton × carbon content 85% × 44 ÷ 12 = 0.3 ton.

<Use of adsorption capacity>
By submerging charcoal in water, it is possible to expect purification of water (lake water and seawater) using charcoal adsorption ability. Charcoal is porous, and the surface area of charcoal baked at high temperature (800 ° C. or higher) is said to be 400 m ² / g. It is important to distinguish and preserve charcoal that should be stored for a long period of time by adsorbing toxic substances using an adsorption function and charcoal that is not adsorbed for toxic substances and that will be stored as it is.

<Production of charcoal in Japan>
(1) Citizen-participation CO ₂ reduction Japanese citizens generally feel close to forests, but in recent years forests and forestry have become a distant world for children living in cities. There are many places that have already made charcoal making into environmental education for children, and while fostering friendship with forests, trees absorb CO ₂ and become wood, and carbonize it into visible carbon for a thousand years. It is desirable to educate children about global warming countermeasures that they can save themselves. The resulting charcoal is purchased by local governments and countries aimed at carbon fixation or water purification. Also, it is not necessary to carry the thinned wood that has been abandoned in the forest far away, and carbonization is possible with simple equipment on site.
(2) Participation of companies Charcoal production and preservation promotion measures can be taken in which the local government or the government purchases charcoal manufactured or purchased by companies and counts the amount of CO ₂ equivalent to the carbon of the charcoal as a reduction amount. Carbonized organic waste such as food industrial waste (juice, beer squeeze, etc.) is also covered.
(3) Administrative support First, the country proposed to the United Nations proper manufacture and preservation of charcoal as a post-harvest timber treatment not approved by the Kyoto Protocol, and appealed the effectiveness of charcoal internationally. It needs to be acknowledged. After that, we promoted the project as a participatory global warming countermeasure project, and purchased charcoal as a water purification material at an appropriate price, or in return for collection and preservation, using the amount of CO ₂ equivalent to the delivered charcoal as the reduction amount of the supplier Measures such as counting are necessary.

<Charcoal production in developing countries>
Tropical areas with a lot of sunshine and abundant rainfall are promising places for charcoal production. According to FAO, since 1990, 10.3 million ha of forests have disappeared every year in developing countries. In addition, it is said that ¼ of the amount of CO ₂ discharged into the air since 1980 was caused by deforestation. Establish a business to carbonize and preserve plantation trees in areas with such degraded forests. This method is the most efficient. That is, when considering a CO ₂ absorption and fixation of more than 100 years of the unit, since only fixed to live in trees at risk for logging and fire, and save felling and carbonized site repeats replanting Is more efficient in the long run. This has the secondary effect of promoting afforestation in developing countries and contributing to the development of surrounding industries.

<Technology and economic support>
Introduce technical support, economic support, and charcoal production technology for tree species suitable for carbonization, and guide efficient coal production. Charcoal production basically does not require expensive equipment, and anyone can do it, but Japanese technology is by far the most efficient coal production technology, so ODA supports simple capital investment and technology introduction. Better. If it is far from Japan and it is uneconomical, it may be used and stored in the country where charcoal is produced, but certain arrangements are necessary.

<Import price>
The charcoal price currently in circulation is charcoal with a high carbon content, and the CIF price is about 25,000 yen / ton. From the CO ₂ fixed cost, it is 25,000 yen ÷ 3 tons = 8,333 yen / ton = 70 US $ / ton CO ₂ . This cost is much smaller than CO ₂ emission reduction cost of Japan's manufacturing industry.

<Quality control>
When the temperature during firing is 300 ° C. or lower, the degree of carbonization is low and the volatile content is high. Although such charcoal is cheap, there is a possibility of ignition when stored and transported in the air, so quality control at the time of manufacture is important for imported charcoal.

<Charcoal storage target amount; Kyoto Protocol reduction target>
In order to confirm whether the present invention is actually possible, the amount and cost of charcoal production were estimated. To achieve the target amount that the government has committed to under the Kyoto Protocol (-6% of emissions in 1990), minus -6% of the government effort target from the existing emissions (+ 14% in 1990) In addition, the case where -8% was reduced by charcoal production was estimated. -8% min is about 90 million tons in terms of the CO ₂ by weight. The amount of charcoal is 30 million tons (about 60 million m ^{3 in} volume). The world's charcoal production in 2003 was about 43 million tons, so the production of 30 million tons of charcoal is not a natural story.

<Required amount of wood>
The required amount of wood is 300 million m ³ . Forest growth amount of Japan is insufficient to clear because it is year 89 million m ^3. 300 million plantations growing amount can be assured of m ³ is not only rich in tropical regions of rainfall. Since the growth rate of fast-growing tropical trees is about 30 m ³ / ha / year, about 10 million ha plantations are required. This area is the same as Japan's planted forest area, which is just one year of the deforested area in developing countries. Plant trees on land for timber production in these areas. If 10 million ha land is planted with fast-growing tropical trees, it will be planted, planted, and felled in 7 years, so 1.5 million ha are planted every year. In the seventh year, 200 m ³ /ha×1.5 million ha = 300 million m ³ of wood is produced. The planting, logging, carbonization, and reforestation processes are sustainable and require very little energy from other sources, and can be said to be extremely environmentally friendly.

  In this way, because the wood is stored by carbonizing the wood and submerging it in water, it becomes possible to store the carbon fixed in the tree for a long period of time, and the effect of preventing global warming can be enhanced. It becomes possible to purify water (lake water and seawater) by using the charcoal adsorption capacity. Moreover, since the wood is carbonized so that the specific gravity exceeds 1, it can be easily submerged in water in the state of charcoal. In addition, the carbonized wood is placed in a container using a material that can withstand long-term storage and is deposited in water, so that storage management of submerged charcoal can be easily performed. Moreover, since the container which puts charcoal reused the material which emits a harmful substance at the time of incineration disposal, it becomes possible to use the material effectively without generating a dioxin-type harmful substance at the time of incineration disposal. In addition, since the carbonized wood is submerged in a lake with a depth that allows easy recovery, it can be easily taken out and reused when the fuel is depleted in the future. In addition, because the wood to be carbonized is wood obtained by cutting a tree in the forest that has passed a certain period of time after planting, or waste wood, the terminal once fixed in the tree is prevented from being released again into the atmosphere. Can do.

It is a figure which shows the physical property of charcoal.

Claims (3)

A method for long-term storage of wood,
Wood obtained by cutting a tree of a forest that has passed a certain period of time after planting , or carbonized waste wood so that the specific gravity exceeds 1, and the carbonized wood in the water of a lake or sea with a depth that can be easily recovered A method for long-term preservation of wood, characterized in that it is preserved by submerging and, if necessary, the preserved carbonized wood is taken out of the water and used as fuel . The method for long-term storage of wood according to claim 1 , wherein the carbonized wood is deposited in water in a container using a material that can withstand long-term storage. The method for long-term storage of wood according to claim 2 , wherein the container reuses a material that emits a harmful substance at the time of incineration.

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