JP6217402B2 - Fuel composition - Google Patents

Description

  The present invention relates to a fuel composition containing a solid content (residue) after hydrothermal treatment of lignocellulose.

Renewable biomass-derived energy has attracted attention against the background of global warming prevention measures. Biomass mainly consists of lignocellulose, and it is used effectively as a solid fuel as it is, or after being separated into cellulose, hemicellulose, and lignin and then converted into ethanol, butanol, etc. It is done in. In recent years, a technique for semi-carbonizing lignocellulose to convert it into a solid fuel having a high energy density is called trefaction, and has attracted particular attention (Patent Documents 1 and 2). In the torsion, normally, lignocellulose in a water-containing state is once dried, then heat-treated, and hemicellulose having a relatively low calorific value is thermally decomposed and removed in lignocellulose, and further compacted and chemically treated. By increasing the energy density physically, the value as a solid fuel is increased. Although the weight reduction and hydrophobization of the fuel are achieved in the toleration, the value as a solid fuel excellent in transportability and storage is increased. However, the effective use of the pyrolyzed hemicellulose has not been sufficiently studied and manufactured. It was only used as an auxiliary fuel in the process.

Further, regarding a fuel composition containing lignocellulose, a method of recovering a residue after saccharification of lignocellulose and reusing it as a fuel and / or fertilizer (Patent Document 3), a method for burning cellulose-containing waste, and combustion ash A combustion system (Patent Document 4) and a fuel pellet (Patent Document 5) mainly composed of coffee extraction residue and bark have been reported.

In the process of producing dissolving pulp from lignocellulose, hot water treatment (prehydrolysis) is used as a pre-process of the kraft cooking method. In the hydrothermal treatment, the hemicellulose contained in the lignocellulose is selectively removed, so that the purity of the cellulose contained in the lignocellulose can be increased. The treated suspension after the hot water treatment is separated into a solid content and a liquid content (filtrate) by a solid-liquid separator, and the solid content separated by the solid-liquid separation is used as a raw material for dissolving pulp. If the liquid component separated by solid-liquid separation can be reused as a by-product, it is desirable because the manufacturing cost of dissolving pulp can be reduced.

JP 2003-206490 A Special table 2009-522097 gazette JP 2008-54676 A JP-A-8-219430 JP 2009-102468 A

An object of the present invention is to provide a fuel composition having a high energy density from lignocellulose.

  The inventors of the present invention separated the treated suspension of lignocellulose after hydrothermal treatment into a solid content and a liquid content (filtrate) with a solid-liquid separator, and concentrated the liquid content. As a result, the present inventors have found that a composition containing a hydrogen atom is excellent as a fuel and completed the present invention.

The present invention includes the following inventions.
(1) The lignocellulose is hydrothermally treated, the treated liquid after the hydrothermal treatment is separated into a solid content and a liquid content by a solid-liquid separator, and the liquid content is concentrated to obtain a fuel composition. A method for producing a fuel composition from lignocellulose.
(2) The fuel according to (1), wherein the content of the phenolic hydroxyl group contained in the fuel composition is 10 to 30 g (dry weight) per 100 g (dry weight) of the solid content of the fuel composition. A method for producing the composition.
(3) The method for producing a fuel composition according to (1) or (2), wherein the hot water treatment is performed at 25 to 200 ° C.

  According to the present invention, a fuel composition having a high energy density is provided from lignocellulose.

Production process of fuel composition from lignocellulose

The lignocellulose used as a raw material for producing the fuel composition of the present invention may be wood or non-wood, and a hardwood material containing a large amount of hemicellulose decomposition products is suitable. Woody materials include trees, woodland residue, thinned wood, chips and bark of waste wood, sawdust generated from sawmills, pruned branches of street trees, construction waste, etc. Both hardwood and conifers are used be able to. Broad-leaved trees include Eucalyptus globulus, Eucalyptus grandis, Eucalyptus urograndis, Eucalyptus pula (us), Eucalyptus pula (us) Examples include, but are not limited to, Acacia mangium and Acacia auricformis. Afforestation trees are preferable from the viewpoint of sustainability of raw material procurement, and tree species suitable for afforestation are preferable. Further, each of hardwood, conifer and non-wood can be used alone or in combination. The combination is not particularly limited. Moreover, it can be used as a raw material at any site such as a bark or a bast portion. Agricultural waste such as kenaf, rice straw, straw, corn cob, bagasse, etc., residue and waste of industrial crops such as oil crops and rubber (for example, EFB: Empty Fruit Bunch), herbaceous energy crop areas Examples include lignocellulose-based lignocelluloses such as Nanthus, Miscanthus and Napiergrass. In addition, as lignocellulose, paper derived from wood, waste paper, pulp, pulp sludge, sludge, sewage sludge, etc., food waste, etc. can be used as raw materials. These lignocelluloses can be used alone or in combination. Lignocellulose can be used as a dry solid, a solid containing water, or a slurry.

In the present invention, the lignocellulose is treated with hot water. Hydrothermal treatment means "warm lignocellulose containing aqueous liquid as it is or add aqueous liquid to lignocellulose (lignocellulose containing aqueous liquid or lignocellulose not containing aqueous liquid) Then, it is defined as a process of heating, or a process of adding water vapor to the lignocellulose as an aqueous liquid and heating it.
The content of the aqueous liquid contained in the lignocellulose during the hydrothermal treatment is not particularly limited, but is preferably 5 to 50 parts by mass of the aqueous liquid, more preferably the aqueous liquid 10 with respect to 1 part by mass (dry weight) of lignocellulose. It is preferable that it is -20 mass parts aqueous liquid. By setting the content of the aqueous liquid contained in the lignocellulose during the hot water treatment within the above range, the hot water extraction rate is improved, and the treatment liquid obtained after the hot water treatment (hereinafter referred to as “hot water treatment liquid”). .) Is separated into a solid content (hereinafter referred to as “hot water solid content”) and a liquid content (hereinafter referred to as “hot water extract”) by a solid-liquid separator, and the liquid content (hot water extract). The total amount of phenolic hydroxyl groups contained in can be increased. The hot water extraction rate is a value calculated by the following calculation formula as a mass percentage of the raw material for a concentrate obtained by concentrating the hot water extract (hereinafter referred to as “fuel composition”). Hot water extraction rate (%) = fuel composition (dry weight) / raw material (absolute dry mass) × 100. The total phenolic hydroxyl group amount is a value measured by the foreign thiocult method. It can be said that the larger the total phenolic hydroxyl group amount, the more lignin that has not undergone chemical modification.

  As the aqueous liquid, water is preferably used, and ion-exchanged water is more preferably used. In addition to water, other solvents such as alcohol, acid, alkali and the like can be added to the aqueous liquid. However, when the amount of acid or alkali added increases, lignin obtained by hot water extraction may be chemically modified. Therefore, it is preferable not to add acid or alkali more than necessary. The pH of the aqueous liquid is preferably neutral, for example, pH 6.5 to 7.5.

The hydrothermal treatment is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, further preferably 70 ° C. or higher, most preferably 80 ° C. or higher, preferably 200 ° C. or lower, while stirring an aqueous lignocellulose suspension. More preferably, it is carried out by heating to a temperature of 180 ° C. or lower, more preferably 150 ° C. or lower, and most preferably 120 ° C. or lower. By setting the temperature of the hydrothermal treatment to 150 ° C. or lower, preferably less than 100 ° C., a composition containing lignin not subjected to chemical modification can be efficiently obtained from the liquid component of the hydrothermal treated product. The hot water treatment may be a batch method or a continuous method. The heating time is preferably 0.1 to 10 hours, more preferably 0.5 to 3 hours. The hot water treatment may be performed under atmospheric pressure or may be performed under pressure.
If the treatment time for the hot water treatment exceeds 10 hours, a reaction vessel for hot water treatment having a large capacity is required, which is undesirable because the production cost increases. The liquid ratio of the hot water treatment is preferably 0.5 to 8.0, more preferably 1.0 to 4.0. If the liquid ratio is lower than 0.5, the hydrolysis reaction is not uniform, which is not desirable. On the other hand, if the liquid ratio is higher than 8.0, it is not preferable because the load at the time of solid-liquid separation of the solid content and the liquid content increases. Moreover, when producing by-products (oligosaccharides, monosaccharides, furfural, etc.) from hemicellulose degradation products contained in the hydrothermal treatment liquid after the hydrothermal treatment, if the liquid ratio is higher than 8.0, the hydrothermal treatment liquid This is not desirable because the concentration of the hemicellulose degradation product contained in the product becomes low and the load required for separation and purification in the subsequent process increases. The apparatus used for the hot water treatment is not particularly limited as long as it is an apparatus that can efficiently perform the hot water treatment.

  The lignocellulose desirably removes foreign matters adhering to the lignocellulose before the hot water treatment. Examples of the method for removing foreign substances include a method in which lignocellulose is immersed in water and then dehydrated. Moreover, the water content of lignocellulose can be increased by immersing lignocellulose in water. Although the apparatus for immersion is not specifically limited, For example, a chip washer can be used. The water for immersion can be used without particular limitation, such as factory water and water recovered from black liquor evaporator, but it is desirable to use water that is as colorless and transparent as possible and close to distilled water. When the lignocellulose is immersed in water, agents such as surfactants and chelating agents can be added as necessary. The dehydrator after immersion can be used without any particular limitation, but a drainer type dehydrator is desirable. It is desirable to prepare the immersion and dehydration conditions so that the lignocellulose after immersion and dehydration contains at least 50% of its own weight of water. If the water content contained in the lignocellulose is too low, the presence of water in the lignocellulose becomes non-uniform, and this is not desirable because the acid hydrolysis reaction of the hemicellulose is not performed uniformly in the subsequent hot water treatment. Moreover, the lignocellulose used for a hot water process can be grind | pulverized as needed before a hot water process.

  As a solid-liquid separation device for separating the hydrothermal treatment liquid obtained by the hydrothermal treatment into a solid content and a liquid content, those known in the art can be used, but are not particularly limited. For example, a mesh (mesh) A strainer or filter having a diameter of 10 μm to 5 cm is employed. As the strainer, a strainer in the range of 40 to 500 μm is preferably employed in order to avoid clogging troubles and avoid the accompanying solid content in the separated liquid as much as possible. A centrifuge may be used as the solid-liquid separator.

  By concentrating the liquid (hot water extract) obtained by solid-liquid separation, a concentrate (hereinafter referred to as “fuel composition”) is obtained. As the concentration treatment apparatus, an apparatus known in the art can be used and is not particularly limited. For example, a rotary evaporator can be used. The concentration treatment is preferably performed at 50 to 70 ° C., preferably by heating for 10 to 60 minutes. The extraction rate of the hot water extract is preferably 3.0 to 10.0%, more preferably 4.0 to 8.0%.

The fuel composition obtained by the above method contains lignin, hemicellulose, moisture and the like. The fuel composition of the present invention is characterized in that the total amount of phenolic hydroxyl groups contained in the fuel composition is high. The total phenolic hydroxyl group amount per 100 g (dry weight) of the fuel composition is preferably 10.0 to 30.0 g (dry weight), more preferably 15 to 30 g (dry weight), and 20 to 30 g (dry weight). Particularly preferred.
In the fuel composition of the present invention, the water content of the fuel composition is preferably 5% by mass or less. The calorific value of the fuel composition is preferably 4000 cal / g or more, more preferably 4500 cal / g or more, and particularly preferably 5000 cal / g or more.

  The fuel composition may be added with the hot water solid content (solid content obtained by separating the hot water treatment liquid obtained after the hot water treatment with a solid-liquid separator).

The hot water extract can separate by-products such as saccharides (xylose, xylooligosaccharide) and furfural contained in the hot water extract before or during concentration from the hot water extract.

The apparatus used for the drying treatment of the fuel composition of the present invention can be used without particular limitation as long as the apparatus can efficiently dry the solid content (residue). Depending on the use of the fuel composition, it can be formed into a pellet-like form before the drying treatment.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.

[Production Example 1]
It implemented by the method shown in FIG. Immerse a beaker containing 10 parts by mass of Eucalyptus globulus forest material coarsely pulverized to a diameter of about 3 to 5 cm with respect to 150 parts by mass of ion-exchanged water in an oil bath while heating at 25 ° C. The suspension was obtained by hydrothermal treatment by stirring at a speed of 60 rpm using an EUROPOWERSTAR CONTROL VISC P7 (manufactured by IKA) for 1 hour.

  This suspension was filtered with a Buchner funnel using a filter (ADVANTEC No. 1), and separated into a solid (hereinafter referred to as “hot water-treated solid”) and a liquid (hot water extract). The liquid content was concentrated by a rotary evaporator and dried to obtain a fuel composition. About the obtained fuel composition, the hot water extraction rate was computed with the following formula. : Hot water extraction rate (%) = fuel composition (dry weight) / raw material (dry weight) × 100). The calorific value of the fuel composition (per dry weight) was measured using a calorimeter (trade name: 1013-J, manufactured by Yoshida Seisakusho Co., Ltd.). Further, the total phenolic hydroxyl group content of the fuel composition was measured by the foreign thiocult method. The results are shown in Table 1.

[Production Example 2]
In Production Example 1, the same operation as in Production Example 1 was performed except that the temperature of the hot water treatment was changed to 50 ° C. The results are shown in Table 1.

[Production Example 3]
In Production Example 1, the same operation as in Production Example 1 was performed except that the temperature of the hot water treatment was changed to 70 ° C. The results are shown in Table 1.

[Production Example 4]
In Production Example 1, the same operation as in Production Example 1 was performed except that the temperature of the hot water treatment was changed to 90 ° C. The results are shown in Table 1.

[Production Example 5]
In Production Example 1, the same operation as in Production Example 1 was performed except that the temperature of the hot water treatment was changed to 120 ° C. The results are shown in Table 1.

[Production Example 6]
In Production Example 1, the same operation as in Production Example 1 was performed except that the temperature of the hot water treatment was changed to 150 ° C. The results are shown in Table 1.

[Production Example 7]
In Production Example 1, the same operation as in Production Example 1 was performed except that the temperature of the hot water treatment was changed to 180 ° C. The results are shown in Table 1.

[Production Example 8]
In Production Example 1, the same operation as in Production Example 1 was performed except that the temperature of the hot water treatment was changed to 200 ° C. The results are shown in Table 1.

As shown in Table 1, lignocellulose was hydrothermally treated (25 ° C., 50 ° C., 70 ° C., 90 ° C., 120 ° C., 150 ° C., 180 ° C., 200 ° C.), and the liquid separated by solid-liquid separation was concentrated. The calorific value of the fuel composition obtained by drying is 4362 cal / g (temperature 25 ° C.), 5087 cal / g (50 ° C.), 5186 cal / g (temperature 70 ° C.), 5260 cal / g (temperature 90 ° C.), They were 5329 cal / g (temperature 120 ° C.), 5210 cal / g (temperature 150 ° C.), 4960 cal / g (temperature 180 ° C.), and 4885 cal / g (temperature 200 ° C.). The total phenolic hydroxyl group content (index of lignin content) contained in the fuel composition was 25.5 g / 100 g (temperature 25 ° C.), 22.4 g / 100 g (50 ° C.), 24.3 g / 100 g (temperature 70). ), 26.7 g / 100 g (temperature 90 ° C.), 26.4 g / 100 g (temperature 120 ° C.), 26.5 g / 100 g (temperature 150 ° C.), 26.2 g / 100 g (temperature 180 ° C.), 26.3 g / 100 g (temperature 200 ° C.).

According to the present invention, a fuel composition having a high energy density can be supplied from lignocellulose.

Claims (2)

The lignocellulose is hydrothermally treated, the treated liquid after the hydrothermal treatment is separated into a solid content and a liquid content by a solid-liquid separator, and the liquid content is concentrated and dried to obtain a fuel composition containing lignin and hemicellulose. a method of manufacturing a fuel composition from lignocellulose containing and this, by performing the hot water treatment at 70 ° C. to 180 ° C.,
The calorific value of the fuel composition is 4500 cal / g or more,
A method for producing a fuel composition, characterized in that The hot water extraction rate by the hot water treatment is in the range of 4.0% to 8.0%.
The manufacturing method of the fuel composition of Claim 1.

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