JP2008297531A - Method for producing biofuel and apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce a biofuel by culturing seaweed on the open sea to fix carbon dioxide inside the body of seaweed through photosynthesis to decrease the carbon dioxide concentration in the air and protects petroleum resource. <P>SOLUTION: The method for producing biofuel comprises a step for crushing oceanic biomass, a step for suspending the crushed oceanic biomass into hot water of 120 to 280°C, heating under high temperature and high pressure, then ejecting it in the atmospheric pressure to obtain the insoluble portion, a step for treating the insoluble portion with ozone to collect a cellulose fraction, a step for hydrolyzing the cellulose fraction to obtain a glucose solution, a step for fermenting the glucose solution into the biofuel, a step for collecting the biofuel from the biofuel fermentation solution, a step for obtaining the biofuel, and a step for treating the waste liquor. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a method for reducing carbon dioxide concentration in the atmosphere, and more particularly to a method and apparatus for producing biofuel from marine biomass as an alternative to petroleum fuel.
“Marine biomass” means biomass (resource crops) that can be harvested in the ocean, floating seafloor and other floating materials, and waste generated in the ocean such as aquaculture equipment waste. , Including.
In addition, “biofuel” indicates one or a mixture of two or more of ethanol, isopropanol, butanol, fatty acid methyl ester (biodiesel), ethylene, and propylene produced using biomass as a raw material.

The massive use of coal and oil has led to depletion of fossil fuel resources such as oil and coal, and an increase in the concentration of carbon dioxide in the atmosphere. In particular, an increase in the concentration of carbon dioxide in the atmosphere causes global warming due to the greenhouse effect, which causes environmental destruction.
As one of the measures to solve this problem, the development of technology for producing biofuel from biomass photosynthesised from carbon dioxide and water by plants and using it as an energy source to replace petroleum fuel is being promoted.

  The relationship between the use of biomass and the concentration of carbon dioxide in the atmosphere is as follows: `` Even if biomass is converted into biofuel and burned to release energy and carbon dioxide, the biomass absorbs solar energy and the plant absorbs solar energy. It is based on the concept of carbon neutral that it does not increase the amount of carbon dioxide because it is photo-synthesized from carbon dioxide and water.

(Biosynthetic pathway of fermentation method for producing biofuel)
The reaction of producing biofuel from biomass using fermentation methods uses metabolic products that biosynthesize fat via pyruvic acid, which is the final product of glucose glycolysis. An outline is shown in FIG.
Acetaldehyde produced by decarboxylation of pyruvate by decarboxylase is reduced to produce ethanol.
The obtained ethanol can be used as automobile gasoline engine fuel.

  Acetacetyl CoA is produced from two molecules of acetyl CoA obtained from pyruvic acid, butyryl CoA is produced in three stages, and butanol is produced via butyraldehyde. In addition, isopropanol is produced from acetoacetyl CoA via acetone. This route is also called acetone / butanol fermentation. The resulting butanol and isopropanol can be used as automobile fuel.

  Butyroylacetyl CoA is produced from butyryl CoA and acetyl CoA, and a carbon chain is extended by two carbons in the same reaction to produce a fatty acid, which is glycerin esterified to produce fat (triacylglyceride) as a final product. Generated. Biodiesel (fatty acid methyl ester) is produced from the obtained fat using sodium methoxide as a catalyst, and this is used as a fuel for a diesel engine.

Thus, the reaction used in the biofuel production method of the present invention is mostly glucose fatty acid metabolic pathway products, and if glucose is used as a raw material to convert fermentative bacteria, the product can be converted without changing the production apparatus. it can.
Furthermore, ethanol can be dehydrated to produce ethylene, isopropanol can be dehydrated to produce propylene, and butanol can be dehydrated to produce butylene and isobutene. Ethylene, propylene, butylene and isobutene can be converted to biofuel. In addition, it is possible to convert raw materials of various petrochemical products such as polyethylene and polypropylene into bio raw materials.

(Manufacture of biofuels)
Development of production technology for ethanol by fermentation is underway as a technology for producing biofuel from biomass and using it as an energy source to replace petroleum fuel.
Agricultural products were first used as raw materials for producing biofuels.
Since starch, which is the main component of agricultural hydrocarbons, can be heated to form soluble starch, and then ethanol fermentation can be performed using yeast, ethanol can be produced relatively easily. Butanol and propanol are also produced using the same raw materials as ethanol.

Development of technology using wood and soft biomass as a second raw material for producing biofuels is in progress.
Since cellulose, which is the main component of wood hydrocarbons, cannot be used as it is for fermentation, a method of hydrolyzing cellulose to produce glucose and fermenting the resulting glucose has been developed. In addition, lignin contained in wood inhibits ethanol fermentation using yeast, so it must be removed before ethanol fermentation. However, the lignin removal process is a high cost factor in the method of producing biofuel from wood. It has become.

For hydrolysis of cellulose, conventionally, a method using an enzyme and a method using an acid catalyst such as dilute sulfuric acid are used.
However, the method using an enzyme is not economical because the enzyme activity is insufficient and the enzyme is expensive.
In addition, the method using an acid catalyst has a problem in that the yield is low, a large amount of acidic waste water is generated, and calcium sulfate is generated as waste because the acid is neutralized with quick lime.

As a new method for hydrolyzing cellulose in wood, Patent Documents 1 and 2 describe methods of producing oligosaccharides by steaming and detonating wood with high-temperature and high-pressure subcritical water. However, this method also reduces the total yield in the step of removing lignin, resulting in a low sugar hydrolysis yield, and it has been difficult to increase the total yield of ethanol to 30% or more.
Further, wood has a large amount of C5 monosaccharides, and C5 monosaccharides are not fermented with ethanol, so that the yield of ethanol is low.
In Patent Documents 3 and 4, a genetically modified bacterium in which an ethanol fermentation gene of a bacterium used for tequila brewing is incorporated into Escherichia coli is used to obtain a high yield from a woody biomass containing xylose, a kind of C5 monosaccharide. A method for producing ethanol is disclosed.

(Marine biomass)
As a third raw material for producing biofuel, seaweed, which is marine biomass that has not been used so far, can be mentioned. Seaweed grows quickly and has a high ability to immobilize carbon dioxide by photosynthesis, so it is expected to be advantageous as a new energy resource that effectively immobilizes carbon dioxide.
For example, Eisenia and beforehand of brown algae, per submarine 1m ^2, it is said that the leaves of 2~3kg is produced by dry weight per year, which is greater than the production amount of land of the forest. Also, the same brown algae Honda Walla is said to produce 8 kg of leaf by dry weight annually, which is more than that of the rainforest.

As a seaweed that propagates widely in Japan, there is the Hibamataceae Honda Wallaceae Honda Walla (hereinafter referred to as Honda Walla).
Fig. 2 shows the Honda Walla. The mature Honda walla is provided with an attachment device 2 and a disk-shaped stem 3 for attaching algae to the rocks on the seabed. There is no organ that absorbs moisture and nutrients from the ground like the roots of land plants, and the entire alga body absorbs and photosynthesizes nutrients. Several main branches 4 extend from the top of the stem 3 and grow to a height of 2 to 4 m. The main branch 4 is provided with a large number of spatula-shaped or elliptical leaves 5 and a large number of egg-shaped airves 6 having protrusions, and becomes self-floating (floats in water).
After a while after maturation, the main branch 4 is cut and becomes a flowing algae, and only the attachment device 2 and the stem 3 remain on the seabed, and a new main branch 4 extends from the stem 3 again in the spring of the following year. In this way, the main branch 4 is renewed every year and has a life of about 3 years. Honda Walla, which has become a floating algae, is important as a place for spawning eggs and fry. Algae is edible.

Regarding a method for artificially cultivating Honda straw, Patent Document 5 describes a method for cultivating seedlings for cultivation from young embryos of Honda Walla. Patent Document 6 describes a method for cultivating seedlings for aquaculture by callus culture of buds of Honda straw.
However, the purpose of these methods is edible use, and there is no description of a method for mass-cultivating or harvesting Honda straw for industrial use.

Regarding the industrial use of seaweed, Patent Document 7 describes an ocean plantation where seaweed grows in the ocean, an offshore plant ship that harvests and partially burns seaweed to produce methanol, formic acid, and hydrogen, and the ocean that supports this. And a satellite system.
Further, Patent Document 8 discloses a method for producing ethanol by using starch as a raw material by heating and removing starch contained in seaweed. However, the amount of starch contained in normal seaweed is small. In addition, the carbohydrates contained in seaweed are different from those of land plants, and no method for producing biofuel from carbohydrates specific to seaweed has been reported.

(Total yield)
The total yield of biofuel is expressed as a percentage of the weight of biofuel produced relative to the weight of the effective raw material used.
(Weight of generated biofuel / Weight of effective raw material used) × 100
If the conversion rate is 100% when converting glucose to ethanol,
(Ethanol molecule × 2 / glucose molecular weight) × 100
= (92.14 × 2 / 180.162) × 100
= 51.14 [%]
≒ 50 [%]
When converting glucose to ethanol by fermentation, the total yield is about 50% even when the conversion rate is 100%.

JP 2004-229607 A Japanese Patent Laid-Open No. 10-327900 US Patent No. 5,000,000 specification US Pat. No. 5,821,093 JP 2004-187574 A JP 2006-129833 A JP 2006-204264 A JP 2003-310288 A

  An object of the present invention is to develop a method and apparatus for producing biofuel from marine biomass.

  The biofuel production method of the present invention for solving such a problem is that the marine biomass is a perennial seaweed that is self-floating by attaching air follicles, and (1) the seaweed 1 attacher after the seaweed 1 has matured Marine biomass harvesting stage that cuts and harvests main branch 4 while leaving 2 and stem 3; (2) Pretreatment stage to shred and pulverize harvested marine biomass; Shredded and crushed marine biomass Is suspended in hot water at 120 to 280 ° C, then boiled into atmospheric pressure, boiled, and rapidly cooled to 100 ° C with the heat of evaporation. Cellulose fraction purification step to obtain a cellulose fraction by purification, and the cellulose fraction is added to hot water at 120 to 280 ° C., then blown into the atmospheric pressure to boil, and rapidly cooled to 100 ° C. with the heat of evaporation to give glucose Manufacturing solution Characterized in that it comprises that a hydrolysis stage, and biofuel production phase including, a.

  Further, in the present invention, the cellulose fraction purification step is a step of collecting the cellulose fraction by treating the insoluble part with one or more treatment agents consisting of ozone, sodium hydroxide and sodium carbonate. Is preferred.

  The present invention also includes a saccharide recovery stage in which a soluble part is collected from the product of the steaming / explosion stage and the saccharide is recovered, and the recovered saccharide is added to hot water at 120 to 280 ° C., and then into atmospheric pressure. Preferably, the method includes a carbohydrate hydrolysis step in which a monosaccharide solution is produced by jetting to boil and quenching to 100 ° C. with heat of evaporation.

Further, the present invention includes a fermentation stage for obtaining a fermentation broth by fermenting a glucose solution, a collection stage for collecting crude biofuel from the fermentation broth, and a biofuel purification stage for refining the crude biofuel. preferable.
The present invention also includes a biofuel production stage comprising a reduction stage for producing a sugar alcohol by reducing a glucose solution, and a hydrocracking stage for producing ethylene from the sugar alcohol using a fluidized bed hydrocracking catalyst. It is preferable.

The present invention also includes a fermentation stage for obtaining a fermentation broth by fermenting a monosaccharide solution, a collection stage for collecting crude biofuel from the fermentation broth, and a biofuel purification stage for refining the crude biofuel. Is preferred.
The present invention also comprises a biofuel production stage comprising a reduction stage for producing a sugar alcohol by reducing a monosaccharide solution, and a hydrocracking stage for producing ethylene from the sugar alcohol using a fluidized bed hydrocracking catalyst. It is preferable to include.

  In addition, the present invention uses a waste liquid recovery stage in which one or more of the effluents generated in each stage of the biofuel production stage are combined to recover organic matter, and the organic matter is combusted in a waste liquid recovery boiler and steam generated in the waste liquid recovery boiler is used. It is preferable to have a power generation stage for generating power.

  In addition, the present invention is to supply water vapor to one or more of a steaming / explosion stage, a hydrolysis stage, and a saccharide hydrolysis stage while using a bleed back pressure turbine generator for the power generation stage. Is preferred.

  In the present invention, it is preferable that the seaweed is a seaweed of the genus Hidamataceae.

  The biofuel production apparatus of the present invention is a perennial seaweed in which marine biomass is self-floating with air bubbles attached to it, and (1) a seaweed holding device 15 for holding an attachment device 2 for seaweed 1 and a seaweed holding device. A buoyancy adjusting device 16 that floats and sinks 15; a seaweed bed unit 9 that is anchored substantially horizontally below the sea surface to a mooring line 13 that connects an anchor 11 and a buoyant body 12 on which a net 14 is installed on the seabed; A marine biomass culture means comprising: a seaweed bed set 8 in which a plurality of seaweed bed units 9 are arranged and arranged at predetermined intervals; and a seaweed bed 7 in which a plurality of seaweed bed sets 8 are installed at predetermined intervals. The marine biomass harvesting means comprises the marine biomass harvesting means for harvesting the main branch 4 while leaving the attachment device 2 and the stem 3 of the seaweed 1 and (2) biofuel production means.

Moreover, the biofuel production means of the present invention comprises pretreatment means for chopping and pulverizing the harvested marine biomass, suspending the chopped and pulverized marine biomass in hot water at 120 to 280 ° C., and then atmospheric pressure. Steaming / explosion means that is boiled in and boiled and rapidly cooled to 100 ° C. by evaporating heat; and a cellulose fraction purification means for collecting and purifying the cellulose fraction by collecting and purifying insoluble parts from the products of the steaming / explosion means The cellulose fraction is added to hot water at 120 to 280 ° C., then blown into the atmospheric pressure to boil, hydrolyzed to produce a glucose solution by quenching to 100 ° C. with heat of evaporation, and the glucose solution is fermented Fermenting means for obtaining a fermented liquor, a collecting means for collecting crude biofuel from the fermented liquor, a biofuel purifying means for purifying the crude biofuel, and an effluent produced in each means A waste liquid recovery unit for recovering the organics combined on the recovered organics were burned in waste recovery boiler, it is preferable to have a power generating means for generating electric power using the steam generated in waste recovery boiler.

  In the present invention, the power generation means is preferably a bleed back pressure turbine generator.

  By producing biofuel from marine biomass and using the resulting biofuel as a substitute for petroleum fuel, it is possible to prevent an increase in carbon dioxide in the atmosphere and contribute to global warming countermeasures. In addition, the amount of petroleum fuel used can be reduced and petroleum resources can be protected.

  Food problems have arisen from the production of biofuels using agricultural products. In addition, if a large amount of quality biomass is used, there is a concern about future competition with the pulp industry. By producing biofuel using marine biomass that has not been used so far, biofuel can be produced without affecting other industries.

  Marine biomass can be stably supplied in large quantities by installing floating algae beds in the open ocean and culturing seaweeds that are self-floating with bubbles.

  By cultivating perennial seaweed that generates bubbles, the weight of seaweed on the harvesting device is reduced, the effect of simplifying the harvesting device is obtained, and harvesting is facilitated by harvesting floating seaweed An effect is obtained.

  Although the main branch 4 of the perennial seaweed 1 germinates from the stem 3, since the conventional harvesting method damaged the stem 3 and the attachment device 2 that supports it, the harvest after the second year fell. By the method of cutting the main branch 4 while leaving the attachment device 2 and stem 3 of the seaweed 1 with the apparatus of the present invention, the main branch 4 can be germinated reliably in the following year, and the yield after the second year can be increased.

  By using the cellulose hydrolysis method of the present invention in which marine biomass is hydrolyzed in three stages including a steaming / explosion stage, a purification stage, and a hydrolysis stage, when a raw material containing lignin is used, the saccharification yield is not reduced. Glucose free from lignin can be obtained in high yield. Moreover, when seaweed is used as a raw material, a highly pure glucose solution can be obtained.

Marine biomass produces compounds different from terrestrial plants, so they can be collected and used. As already used, large-scale and inexpensive production of alginic acid, fucodyne, plant protein, etc. is possible. It can also be used by collecting the seaweed fat and modifying it into biodiesel oil.
Since seaweed takes in heavy metals from seawater, it is possible to use the sea as a valuable heavy metal resource by collecting heavy metals from seaweed. In particular, recovery of natural uranium, which is a raw material for nuclear power generation, is expected.

  By collecting organic matter from the waste liquid, the amount of waste liquid to be discharged is reduced to reduce the environmental burden of the facility. At the same time, biomass energy is recovered by burning the collected organic matter to generate electricity, and the power required for operation And a self-supporting system that supplies the entire amount of water vapor, the total system can be operated economically. In addition, this makes it possible to immediately operate the system even in areas where infrastructure such as electric power is delayed.

  By changing the fermenting bacteria that produce biofuel, it is possible to provide a system that can respond to changes in the production object without changing the factory equipment. Accordingly, it is possible to develop a system configuration that can flexibly adjust the production items and the production amount in response to short-term fluctuations in the supply and demand of biofuels and changes in the medium- to long-term demand structure.

Embodiments of the present invention will be described below with reference to the drawings. The following description is for clearly explaining the present invention, and does not limit the scope of rights of the present invention.
(A) Marine biomass farming and harvesting (selection of biomass raw materials)
The plan to replace automotive fuel with biofuel requires a large amount of biomass as a raw material.
Therefore, if existing agricultural raw materials are used as raw materials, shortage of raw materials and rising raw material prices cannot be avoided. For example, the production of biofuels made from agricultural products such as corn and sugar cane has led to soaring raw material prices and food prices due to food shortages.

  Development of technology using wood as a raw material for producing biofuels is in progress. However, trees take time to grow, and forests are not highly self-regenerating. In order to supply a large amount of woody biomass from forests to replace gasoline, it is necessary to create a new and vast forest, and enormous effort and time are required. In Japan, where the land is small, there are few lands where new forests can be created.

For this reason, it is necessary to develop new biomass that has not been used so far.
Seaweed is attracting attention as a new biomass.
The present invention establishes a seaweed cultivation method for culturing seaweed by installing a floating seaweed basin in the open ocean, and a seaweed harvesting method for efficiently harvesting the seaweed, thereby producing a large amount of marine biomass as a raw material, and The purpose is to provide a stable supply.
In addition, a large amount of driftwood floats in the ocean depending on the sea area, and a large amount of plant biomass including waste from the seaweed beds according to the present invention is discharged into the ocean. These belong to biomass containing lignin. In the present invention, it is an object to develop a method in which these plant biomass can be used as a raw material for producing biofuel, and to use it as marine biomass, and also contribute to marine environmental conservation.

(Selection of seaweed to be cultured)
The present invention is characterized by culturing perennial seaweed that is self-floating by attaching air vesicles 6.
By cultivating perennial seaweed that generates air bubbles, the weight of seaweed on the harvesting device can be reduced and the harvesting device can be simplified, and harvesting can be facilitated by harvesting floating seaweed 1 Effect is obtained. Also, by harvesting the main branch 4 by harvesting the main branch 4 while leaving the attachment 2 and stem 3 of the seaweed 1, the main branch 4 can be reliably generated in the following year from the perennial seaweed 1, and the characteristics of the perennial seaweed are utilized. As a result, the productivity of the aquaculture work can be increased and the facility for supplying seedlings of seaweed 1 can be reduced in size.
Moreover, it is more preferable that it is the seaweed 1 which becomes 2 m or more in height when growing. Productivity can be increased by harvesting large seaweed 1.

As the seaweed 1 that satisfies the above-mentioned conditions, specifically, the seaweed 1 of the genus Clevisidae is preferred. The seaweed 1 of the Honda Wallaceae is characterized by having air cells 6.
The seaweeds of the family Hawkella are divided into a plurality of genera and are of various varieties. , Hijiki, Yokomoku, Miyabemoku, Obamoku, Yoremoku, Sugimoku Sugimoku, Uganomok Uganomok, Yabamoku Yaebanoku, Joromok Joromok.

  Among these, the most preferred example is Hibamatidae (Hondamataceae). When grown, Honda Walla is a perennial seaweed that becomes self-floating with bubbles 6 and has a height of 2 to 4 m.

(Equipment for aquaculture of marine biomass)
FIG. 3 shows the configuration of the algae ground 7 for cultivating marine biomass according to the present invention.
Seagrass beds 7, effective cultivation area thereof is preferably 1,000～50,000Km ^2, the effective cultivation area is more preferably from 5,000~40,000km ^2.
If the effective cultivation area is smaller than 1,000 km ² , the effect of increasing the size of the algae ground 7 cannot be exhibited, and the operation efficiency is deteriorated. Although there is no restriction | limiting in the upper limit of an effective cultivation area, when it exceeds 40,000 km ² , since one side of the algae ground 7 will exceed 200 km, management will become inadequate.

Since it is practically impossible to install such a large-scale seaweed bed 7 in the coastal area, the present invention installs a floating-type seaweed bed in the open ocean.
As shown in FIG. 3 (A), the seaweed basin 7 is configured by opening a water surface to be a route 24 and a fishing ground 25 for a general ship and installing a plurality of seaweed basins 8. The number of seaweed bed sets 8 installed in the seaweed bed 7 is 2 to 100, more preferably 5 to 50, and most preferably 5 to 20.
The seaweed bed set 8 is a combined set of aquaculture-manufacturing equipment having seaweed aquaculture equipment and biofuel production equipment 29. Whether the biofuel production facility 29 is constructed on land or on the sea is preferably determined according to the conditions of the place where the seaweed bed set 8 is installed.
The seaweed bed set 8 includes a management site 28, a marine biomass transport tanker 30 with a loading capacity of 5 to 500,000 tons, a medium-sized work boat 31 with a loading capacity of 100 to 1,000 tons, a small high-speed seaweed cutter boat 32, Is provided.

The medium-sized work ship 31 is a catamaran, and harvests the Honda walla, performs the water washing work of the harvested Honda walla, and carries it. Also, when harvesting of Honda walla is not performed, repair work for damaged parts and new construction of seaweed beds will be conducted. Therefore, it is preferable that the medium-sized work boat 31 is equipped with a marine cogeneration generator and has multiple functions.
Furthermore, it is preferable that the small high-speed seaweed cutter boat 32 includes an underwater sensor device and has a function of cutting the main branch 4 of the seaweed 1 while leaving the attachment device 2 and the stem 3 of the seaweed 1. The height of cutting is preferably 5 to 30 cm from the seaweed holding device 15, and more preferably 10 to 20 cm from the seaweed holding device 15.
The fuel for the medium-sized work boat 31 and the small high-speed seaweed cutter boat 32 is preferably biodiesel produced by recovering and modifying the fat content in Honda straw.

As shown in FIG. 1B, the seaweed bed set 8 includes a small water passage 21 through which a small high-speed seaweed cutter boat 32 can pass, a middle water passage 22 through which a medium-sized work boat 31 can pass, and an oceanic biomass transport tanker 30. And a large water channel 23, which is a water channel, and a plurality of seaweed beds 9 are arranged and juxtaposed on the sea surface divided by various water channels.
The number of seaweed bed units 9 installed in the seaweed bed set 8 is 10,000 to 500,000, preferably 40,000 to 400,000, and most preferably 50,000 to 200,000.

As shown in FIGS. 3C and 3D, the minimum constituent unit of the seaweed bed 7 of the present invention is a seaweed bed unit 9. The seaweed bed unit 9 has a net 14 that is anchored substantially horizontally below the surface of the mooring line 13 that connects the anchor 11 and the buoyant body 12 installed on the seabed 17, and a seaweed holder that holds the attachment device 2 of the seaweed 1. It is a floating-type seaweed bed including the instrument 15 and one or more buoyancy adjusting devices 16 for floating and sinking the seaweed holding instrument 15.
In the ocean, there are thermocline layers with different water temperatures between the middle and lower layers rich in minerals and the surface layer, and the surface layer and the middle layer do not cross. For this reason, minerals below the middle layer do not reach the surface layer.
It is preferable to install a stirrer that disturbs the thermal climatic layer on the mooring line 13 near the thermal climatic layer, disturb the thermal climatic layer using the vertical movement caused by waves, and replenish the surface layer with a mineral component. In particular, in the winter season after planting seedlings, the temperature climbing layer rises to about 15 m below the surface of the water and the waves are large, so a stirring device using wave motion is effective.

  The larger the seaweed bed unit 9 is, the higher is the efficiency in culturing and harvesting, but the tension for stretching the seaweed holding device 15 is increased. Considering these points, the seaweed bed unit 9 is preferably a square or rectangle having a side of 10 to 10,000 m, more preferably a square or rectangle having a side of 20 to 500 m, and most preferably a square or rectangle having a side of 50 to 200 m. preferable.

The seaweed does not have an organ corresponding to the “root” of the land plant, and is attached to the seabed with the attachment device 2 (provisional root). Therefore, in order to cultivate the seaweed 1, a seaweed holding device 15 for holding the attachment device 2 for the seaweed 1 is necessary.
Any type of seaweed holding device 15 may be used as long as it can firmly hold the attachment device 2 of seaweed 1, but in consideration of convenience of harvesting, a rope-like device is preferable. Since it is used in large quantities and discarded after being used for several years, natural materials are more preferable in view of environmental impact. As a most preferable example, a rope in which a rope of rice straw is reinforced with natural fibers can be exemplified. The rice straw rope can be mixed with marine biomass and used as a raw material for biomass.

Since the anchor 11, the buoyant body 12, and the mooring line 13 must be enlarged when the water depth of the place where the seaweed basin 7 is installed is deep, it is not economical. The depth of the place where the seaweed basin 7 is constructed is preferably within 700 m, more preferably within 500 m.
The seaweed bed 7 of the present invention is installed in the open ocean, but the open ocean has larger waves than the coastal sea area. The sea can become rough due to low pressures and typhoons. In addition, when the seaweed bed 7 is installed on the Japanese side, the days when the sea gets rough due to the seasonal wind increase in winter. The winter season is a season in which the seaweed 1 held in the seaweed holding device 15 is grown.
If the seaweed bed unit 9 is levitated near the sea surface when the sea is rough, there is a possibility that the seaweed body of the seaweed 1 may be cut or the aquaculture device may be damaged due to rough waves. In the case of stormy weather, it is desirable to reduce the buoyancy of the buoyancy adjusting device 16 so that the seaweed bed unit 9 is submerged under the sea surface to avoid the influence of rough waves.

The seaweed bed unit 9 of the present invention includes one or more buoyancy control devices 16 for floating and sinking the seaweed holding device 15. The buoyancy control device 16 is one or more buoys, and levitation / sedimentation is performed by enclosing a liquefied gas that vaporizes / condenses in accordance with the increase / decrease of the volume of gas sealed in the buoyancy control device 16 and / or the water temperature. It can be carried out.
The depth of sinking the seaweed holding device 15 is preferably 7 to 13 m when settling for a long time in winter, and even if it is settling for a short period of time due to storminess, it is limited to the natural habitat limit of 20 m. To do.

(Marine biomass harvesting)
The harvest of seaweed 1 begins in the spring of the third year after the emergence of the young dragonfly, and the harvest ends at least by the typhoon season.
Harvesting leaves the attachment device 2 and the stem 3 of the seaweed 1 and winds up the small high-speed seaweed cutter boat 32 that cuts the main branch 4 from the seaweed holding device 15 and the seaweed 1 that is cut off and floats on the sea. And a medium-sized work ship 31 that transports the harvested seaweed 1 to the marine biomass transport tanker 30.
By harvesting seaweed by the above method, harvesting work can be performed efficiently.
The unit area yield of the marine biomass 1 is desirably 5.5 to 8.0 kg / m ² or more in dry weight per year.

(B) Production of biofuel FIG. 4 shows the basic process of the present invention.
(Hydrolysis of cellulose)
The marine biomass of the present invention is a plant containing cellulose. Since cellulose cannot be used for fermentation as it is, a method of hydrolyzing cellulose to produce glucose and fermenting the obtained glucose has been developed.
Among marine biomass, when seaweed is used as a raw material, the seaweed polysaccharide contains a large amount of polysaccharides other than cellulose, so the monosaccharide obtained by hydrolyzing seaweed contains a monosaccharide other than glucose. In the fermentation reaction, monosaccharides other than glucose are not used, and tend to exhibit a competitive inhibitory action with glucose, thus reducing the fermentation yield. Therefore, when seaweed is used as a raw material, it is necessary to develop a method for collecting highly pure cellulose and hemicellulose by separating polysaccharides other than cellulose and hemicellulose in seaweed.

  On the other hand, when using woody biomass such as driftwood and soft biomass among marine biomass, a method for removing lignin must be developed.

As a new method for hydrolyzing biomass, a method of producing glucose by steaming and detonating with hot water at 120 to 280 ° C. has been studied.
In the hydrolysis of marine biomass by steaming and detonation processes, when biomass containing lignin is used as a raw material, the lignin remains in the product when the yield of glucose is increased. Decreases. When hydrolysis is performed under the conditions for decomposing lignin, excessive decomposition of carbohydrates proceeds and the yield of glucose decreases.
Currently, operation is performed under conditions involving excessive decomposition of glucose and xylose in order to remove lignin. As a result, the yield of hydrolysis of sugar is low. When producing ethanol, the overall yield should be increased to 30% or more. Is said to be difficult.

On the other hand, in the fermentation stage from glucose to ethanol, a conversion rate of almost 100% is achieved at the laboratory level, and it is said that it is 90% or more even at the industrial level.
In addition, a bacterium that has been genetically modified so as to assimilate xylose, which is a kind of C5 monosaccharide contained in a large amount in woody biomass, has also been developed.
That is, if a saccharide composed of glucose and xylose can be produced in high yield without containing a fermentation inhibitor, the yield of biofuel can be increased.
Therefore, it is an object of the present invention to develop a method for producing glucose from marine biomass with high yield.

(Hydrolysis method of the present invention)
The present invention includes: 1) a cooking / explosion stage in which insoluble parts are not decomposed, but starch and other saccharides are decomposed and become soluble by being decomposed, and the insoluble part is collected by 2). A marine biomass hydrolysis process comprising three stages: a purification stage for removing the above substances, and 3) a hydrolysis stage for hydrolyzing the insoluble part by steaming and explosion again to obtain glucose.

When seaweed is used as a raw material, sugars other than cellulose are decomposed and become soluble by performing a steaming / explosion process at 120 to 180 ° C. in step 1). it can. Insoluble matter contains alginic acid, which can be removed by washing with a solution of sodium hydroxide in step 2). In this way, highly pure cellulose can be obtained.
When marine biomass containing lignin is used as a raw material, the solid wood structure composed of cellulose and lignin is partially destroyed by the steaming / explosion process of 1) above. The woody biomass modified in this way can be easily dissolved or decomposed and solubilized and removed by causing the treating agent to act in the step 2), or by dissolving or dissolving it.

Examples of the treating agent include ozone, hydrogen peroxide, sodium hydroxide, sodium sulfide, sodium hydrogen sulfite, sodium sulfite, sodium sulfate, chlorine, hypochlorous acid, sodium hypochlorite, and sodium carbonate. As the most preferable example, ozone can be mentioned. Following the purification step, high purity glucose can be produced with high yield by subjecting the obtained cellulose to a steaming / explosion step at 230 to 260 ° C. in the step 3).

(Use of alginic acid)
Polysaccharides other than cellulose and hemicellulose in the sorted seaweed contain about 30% alginic acid. Alginic acid is a linear polymer in which β-D-mannuronic acid and α-L-guluronic acid are linked by 1-4. Alginic acid can be sold as a useful substance, but a huge amount of alginic acid is recovered compared to the market scale.
In addition, carbohydrates are excessively decomposed to produce a large amount of fermentation inhibiting substances. Conventionally, this fermentation inhibitor has been discarded, causing a reduction in the total yield.

In order to solve such a problem, the present invention also includes developing a new method for producing biofuel from alginic acid. This includes application to monosaccharides such as glucose and xylose.
For fermentation inhibitors produced by overdegradation of carbohydrates composed of D-glucose, -D-mannuronic acid, and L-guluronic acid, we developed a high selectivity technology and artificial enzyme. To produce biofuel.

(Recovery and use of waste liquid)
When biomass is processed on a large scale, a large amount of waste liquid residue is generated. For example, assuming that the yield in the case of producing ethanol from woody biomass is 30%, biomass of about 40% of the raw material is discharged into the waste liquid. If this is discharged as it is, a new environmental pollution problem will be caused. Furthermore, the method of the present invention is based on the premise that a large amount of electric power and high-temperature and high-pressure steam can be used. However, if these are directly or indirectly burned and supplied, it is necessary to protect petroleum resources. It does not meet the object of the present invention, ie, reduction of carbon dioxide in the atmosphere.

The present invention recovers biomass discarded from the effluent from each process, burns it with a recovery boiler, recovers the treated material, generates electricity using the combustion heat, and self-supplies high-temperature and high-pressure steam. Provide a self-supporting system that can
The energy obtained from waste liquid recovery is enormous, which makes it possible to reduce the cost of biofuel. By collecting energy from the waste liquid, an effect that the production facility for biofuel according to the present invention can be established economically is obtained.
Furthermore, it is possible to avoid the cause of environmental pollution.

(Responding to changes in the demand structure of biofuels)
In order to use marine biomass, a large-scale artificial seaweed bed must be constructed, and basic academic research on marine organisms is also necessary. That is, enormous investment and a long development period are required to use marine biomass as a new biomass resource.
On the other hand, bioethanol cannot be expected to spread immediately as an alternative fuel for petroleum. In addition, considering the rapid increase in the number of new diesel engine vehicles sold in Europe and the United States, demand for biodiesel is expected to increase in the medium to long term. In addition, considering the development trend of fuel cell vehicles, there is a possibility that the fuel supply and demand structure for automobiles will change in the future.
Considering such circumstances, it is dangerous to limit the target of biomass development to bioethanol that is currently being developed.

Therefore, the present invention includes, as part of the problem, developing a system configuration that can flexibly adjust the production items and production volume in response to short-term fluctuations in the supply and demand of biofuels and changes in demand structure over the medium to long term .
That is, the present invention is based on the steps of producing glucose with high yield from marine biomass, and recovering and burning the waste liquid and recovering its energy from electric power, high-temperature and high-pressure steam, and a treatment agent. Provided is a method obtained by fermentation.

A known method is basically applied to the fermentation process for obtaining biofuel. The fermentation process of ethanol, isopropanol and butanol is known.
The biosynthetic pathway of fat is common from microorganisms to higher organisms, and bacteria that produce fat are also known. However, an industrial process for converting glucose into fats and oils (fatty acid triglycerides) by fermentation has not been developed. This is because the fats and oils obtained by fermentation cannot be used as food, so there was no demand for the fats and oils produced by fermentation. However, in the future production of biodiesel, it is necessary to compare the usefulness between agricultural products and fermentation methods using glucose as a raw material.
Bioethylene is produced from useful components such as furfural contained in the waste liquid and converted into biofuels and chemical products.
As described above, the present invention can change the production item of biofuel without changing the production apparatus if the bacteria to be fermented is changed. Therefore, according to the method of the present invention, short-term fluctuations in the supply and demand of biofuel and medium to long term It is possible to adjust the production items and the production volume for various demand structure changes.

Below, each process of the biofuel manufacturing stage is demonstrated according to the flowchart of FIG.
(First step) Pretreatment stage Marine biomass is shredded and pulverized to produce raw materials. When using seaweed as a raw material, it is preferable to extract an oil-soluble part such as fat with an organic solvent after washing with water and removing salt. The organic solvent is preferably biofuel which is a product of this project. The recovered fat is methyl esterified in methanol using sodium methoxide as a catalyst, reformed into biodiesel oil, and used as fuel for medium-sized work boats. The biofuel used as the extraction solvent is recovered and reused.
Moreover, when a raw material plant is a seaweed, in order to prevent the component in seaweed to gelatinize, it is preferable to heat at 50-95 degreeC.

  Furthermore, an alkali metal salt can be added to the raw material. Examples of the alkali metal salt include sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium sulfide. Most preferably, sodium hydroxide and sodium sulfide can be exemplified. The purpose of adding an alkaline substance is to improve the yield of insoluble parts mainly composed of cellulose in the steaming / explosion process, to prevent the components in seaweed from gelling, and to dissolve alginic acid. is there.

(Second Step) Steaming / Explosion Stage <2-1> Using Raw Material Containing Lignin FIG.
The steaming / explosion device 40 is a pressure cooker 43 having a 1) a raw material supply unit 41 installed above, and 2) a pretreatment unit 48 for pretreatment of the raw material with water vapor 46, and a raw material supply unit 41. A raw material pressure inlet 44, a preheating means 45 for supplying steam to the raw material supply unit 41, a pipe 47 for supplying water vapor 46, hot water 49 stored in the lower portion of the pressure cooker 43, and a bottom portion A steaming part 42 comprising an adiabatic expansion nozzle 50 installed on the surface, and 3) connected to the adiabatic expansion nozzle 50, an atmospheric pressure steam outlet 51, a soluble part outlet 52, and a solid-liquid separator. 53, and a heat-insulating / expanding portion 54 that includes 53.

The marine biomass is preheated by the preheating means 45 in the raw material supply section 41, then supplied from the pressure inlet 44 to the pressure kettle 43, and pretreated by the high temperature and high pressure steam 46 in the upper pretreatment section 48. After that, it falls into the lower hot water 49 and is cooked at 120-180 ° C. under pressure.
Although reaction time is influenced by reaction temperature, the range for 1 to 60 minutes is preferable, and the range for 5 to 30 minutes is more preferable. It is preferable that the optimum conditions for the reaction temperature and reaction time be determined in advance in accordance with the apparatus and purpose.
The steamed marine biomass is ejected from the adiabatic expansion nozzle 50 to the adiabatic expansion part 54 at atmospheric pressure, thereby rapidly depressurizing to atmospheric pressure, boiling and exploding, and rapidly cooled to 100 ° C. with the heat of evaporation.

The adiabatic expansion part 54 is preferably an expansion turbine 55 shown in FIG. When the expansion turbine 55 is used for the adiabatic expansion section 54, the adiabatic expansion nozzle 50 is connected to the steam inlet of the expansion turbine 55, and the reaction product, steam, and hot water are discharged from the expansion turbine outlet 56.
The expansion turbine 55 is a turbine having a radial turbine type rotor blade, and the expansion turbine generator provided with the expansion turbine 55 is a generator that is generally used for recovering energy from exhaust gas. The energy generated by the adiabatic expansion in which the hot water 49 is released to the atmospheric pressure by the expansion turbine generator can be recovered. Moreover, although the adiabatic expansion part 54 generates a large noise, the adiabatic expansion part 54 can be prevented from being generated by using the adiabatic expansion part 54 as an expansion turbine 55.
The slurry generated in the adiabatic expansion part 54 is separated into a soluble part and an insoluble part by the solid-liquid separator 53. The target cellulose is contained in the insoluble part. Preferable examples of the solid-liquid separation device 53 include a screw press, a filtration device, a centrifuge, and a country cleaner.

Low boiling components such as iodine and furfural and useful components that flow out by steam distillation are recovered from the liquid condensed steam. The condensate is sent to the eighth step when recovering useful substances and carbohydrates, and is sent to the tenth step when not recovering or discharged as waste water as it is.
The soluble part is sent to the eighth step or sent to the waste water treatment step of the tenth step.

<2-2> When seaweed is used as a raw material {2-2A} When neutral and steaming / explosion process is performed Neutralize by adding alkali metal salt to shredded and ground marine biomass, <2 A steaming / explosion process is performed under the same conditions as -1> to obtain an insoluble part. Examples of the alkali metal salt include sodium hydroxide, potassium hydroxide, and sodium carbonate. The purpose of the addition of the alkaline substance is to improve the yield of the insoluble part mainly composed of cellulose in the steaming / explosion process and to prevent the components in the marine biomass from gelling. In this case, the insoluble part contains cellulose and alginic acid.

<2-2B> When adding alkali and performing steaming / explosion process Add excess caustic alkali than neutralization equivalent of alginic acid contained in the raw material, and cook / explode under the same conditions as in <2-1A> above A process is performed and the insoluble part which has a cellulose as a main component is obtained. Hemicellulose and alkali metal alginate are contained in the soluble part. The insoluble part is washed with water to separate the cellulose. As the caustic, sodium hydroxide is preferable.

(Third step) Purification step <3-1> When using raw material containing lignin When using raw material of marine biomass containing lignin, the insoluble part contains lignin that becomes a fermentation inhibitor, so chemicals Treat to degrade lignin.
Examples of preferable chemicals include ozone, chlorine, hypochlorite, and hydrogen peroxide. Among them, ozone can be given as the most preferable example.

<3-2> When seaweed is used as a raw material {3-2A} When neutral and steaming / explosion is performed The obtained insoluble matter is heated with an aqueous solution containing an alkaline substance equal to or more than alginic acid. Preferred examples of the alkaline substance include sodium hydroxide and sodium carbonate. Alginic acid dissolves as sodium alginate.
Carbohydrates other than cellulose are removed by washing with water to separate the cellulose.
Acid is added to the solution to make it acidic, or calcium salt is added to precipitate alginic acid as alginic acid or calcium alginate and separate.

When {3-2B} alkali is added to perform the steaming / explosion process By washing the insoluble part with water, carbohydrates other than cellulose can be removed by washing with water, and a cellulose fraction can be obtained.
An acid is added to a soluble part containing sodium alginate and hemicellulose, or a calcium salt is added to precipitate and separate alginic acid or calcium alginate. Hemicellulose remains in the soluble part.
In addition, when high purity cellulose is obtained in the steaming / explosion process in the second step, the insoluble matter obtained in the second step is directly hydrolyzed in the fourth step without performing the purification step in the third step. Can be sent to the process.
The effluent using the treatment material in the purification step of the third step is preferably collected separately from other effluents to recover useful materials and treat the waste liquid, or send it to the waste water treatment process. The other discharged liquid is preferably sent to the useful substance recovery step of the eighth step when recovering useful substances and carbohydrates, and to the waste liquid treatment step of the tenth step when not recovering.

(4th process) Hydrolysis process The cellulose obtained at the 3rd process is hydrolyzed at 230-280 degreeC with the steaming / explosion apparatus used at the 2nd process, and a glucose solution is obtained.
After completion of the reaction, the glucose solution is concentrated to obtain a concentrated glucose solution and crystallized by adding seed crystals. As a method for concentrating the reaction solution, a reverse osmotic pressure membrane method and a functional membrane method can be used in addition to the distillation method. In the crystallization, it is preferable to add a hydrophilic organic solvent such as ethanol or methanol to accelerate the crystallization or make the separation operation more efficient.
The reaction solution of the hydrolysis step of the fourth step can be used for biofuel fermentation reaction by adjusting the concentration by concentration or dilution without performing purification operation by crystallization of glucose and sending it to the fermentation step of the fifth step. .
The discharged liquid in this step is preferably sent to the useful substance recovery step of the eighth step when recovering useful substances and carbohydrates, and to the waste liquid treatment step of the tenth step when not recovering.

(Fifth Step) Biofuel Fermentation Step The problems of the fifth step are the presence or absence of a fermentation inhibitor in the reaction solution and the amount of monosaccharide available for biofuel fermentation contained in the raw sugar solution. It is important to remove fermentation inhibitors and reduce the amount of monosaccharides that are not available for fermentation.
Development of enzymes that are not affected by fermentation-inhibiting substances, enzymes that ferment biofuels using sugars other than glucose, and enzymes that isomerize sugars into usable monosaccharides is desired.

<5-1> Ethanol fermentation process Ethanol fermentation is performed by bringing ethanol fermentation yeast into contact with a solution of glucose dissolved in water.
The ethanol fermentation enzyme is not particularly limited, and any enzyme can be used.
As a form of utilization of ethanol fermentation enzyme, in addition to the conventional method using live bacteria and the method using immobilized enzyme, as a new method, a method using genetically modified bacteria and a survival-independent bacterium (RITE bacteria) are used. Method.
Since there are differences in resistance to fermentation inhibitors and substrate selectivity between these methods, it is desirable to select an optimal enzyme according to the raw material.
When using woody biomass, it is preferable to use a genetically modified bacterium capable of degrading C5 carbon sugar described in Patent Documents 1 and 2.

<5-2> Butanol fermentation step Acetone / butanol fermentation is carried out by bringing acetone / butanol fermentation bacteria into contact with a solution of glucose dissolved in water. In the present invention, acetone-butanol fermenting bacteria are not particularly limited, and any enzyme can be used. As a preferable example, bacteria of the genus Clostridium can be exemplified.
In addition, it is desired to develop an acetone-butanol fermenting bacterium having a high productivity in producing butanol with suppressed production of acetone.
<5-3> Isopropanol fermentation step An isopropanol-producing bacterium is added to a solution in which glucose is dissolved in water to carry out isopropanol fermentation. Contrary to the butanol fermentation of the previous section, it is desired to develop a fungus with high isopropanol productivity that suppresses the production of butanol.
<5-4> Fat Fermentation Step A fat-producing bacterium is added to a solution in which glucose is dissolved in water and fermented.

<5-5> Ethylene Production Process In the ethylene production process, a process for producing biofuel from monosaccharides obtained by hydrolyzing glucose and alginic acid, and a process for producing biofuel from hyperdegradation products of glucose and alginic acid, There are two types of processes.
(Process for producing ethylene from monosaccharides)
A monoalcohol or uronic acid containing D-glucose, L-glucuronic acid and D-mannuronic acid obtained by hydrolyzing glucose or alginic acid is reduced to produce a sugar alcohol. The sugar alcohol used here may be a sugar having any three-dimensional structure as long as the sugar alcohol has 6 carbon atoms.
Monosaccharide or uronic acid is reduced by known reactions such as catalytic reduction using hydrogen with a metal catalyst such as platinum, palladium, nickel, cobalt, or using a reducing agent such as sodium borohydride or lithium aluminum hydride. Can be used.
Ethylene and propylene are produced by a cracking reaction in the presence of hydrogen using a fluidized bed hydrocracking catalyst.
The fluidized bed hydrocracking catalyst is a solid acid catalyst granulated into fine particles of 40 to 80 μm, and has been put to practical use in petroleum cracking reactions and the like. Reaction selectivity is exhibited depending on the shape of the catalyst and carrier and the size of the pores.
(Method for producing ethylene from single overdecomposition product)
In the process of producing biofuel from the hyperdegradation products of glucose and alginic acid, biofuel is produced by developing high selectivity technology and artificial enzymes of the product.

<5-6> Supply and demand adjustment process In the Example, the production target value (weight ratio (%) of effective raw materials) was set as follows.
Bioethanol production target 66% (= 58/88)
Biobutanol production target 34% (= 30/88)
Biopropanol production target 0%
Bioethylene production target 0%
Fat production target 0%
Cellulose shipment volume 0%
Alginic acid shipment volume 0%

(Sixth Step) Biofuel Concentration Step <6-1> Ethanol Concentration Step The ethanol concentration method is not particularly limited as long as it is efficient.
Conventionally, ethanol was produced by distilling an ethanol fermentation broth. However, when ethanol is produced by this method, a large amount of energy is consumed, and in order to obtain this energy, fuel is burned and carbon dioxide gas is released, so that there is a problem that the effect of reducing carbon dioxide gas does not increase.

In order to solve this problem, various membrane separation methods have been studied for ethanol-water separation. Recently, a biofuel enrichment method using the principle of gate membrane has been developed. This membrane is coated with a special polymer that shrinks and opens the pores when the biofuel concentration increases, inside the fine pores opened in the biofuel-permeable polyethylene membrane. A functional membrane with molecular recognition that is controlled by the above components. By using this membrane, 60 to 90% biofuel can be obtained with low energy consumption.
The discharged liquid in this step is sent to the eighth step when recovering useful substances and carbohydrates, and to the tenth step when not recovering.

<6-2> Isopropanol concentration step The concentration method of isopropanol is not particularly limited as long as it is efficient. The same method as that used in the ethanol concentration step can be applied.
<6-3> Butanol concentration step The concentration method of butanol is not particularly limited as long as it is efficient. In addition to the method used in the ethanol concentration step, an extraction method can also be used. Also, since butanol azeotropes with water and separates, steam distillation can also be applied.
<6-4> Fat Concentration Step The fat concentration method is not particularly limited as long as it is efficient. Since it is not preferable that the methanolysis process of the next process contains an acid. It is important to remove the acid.

(Seventh step) Biofuel purification step <7-1> Ethanol purification step The biofuel is passed through a zeolite column to absorb moisture. The zeolite that has absorbed moisture is dried by sending heated air and reused. 99.5% ethanol is obtained.
<7-2> Butanol purification step Purify by distillation.
<7-3> Isopropanol purification step Purified by a distillation method.
<7-4> Fat (Biodiesel) Purification Step The obtained fat is dissolved in 3 to 20 parts of methanol, and 0.01 to 10% sodium methoxide of the raw material fat is added to synthesize fatty acid methyl ester.
Methanol is removed from the reaction solution by distillation, and the resulting crude fatty acid methyl ester is washed with water and then purified by distillation.

(Eighth Step) Useful Substance Recovery, Fermentation Inhibitory Substance Removal, Unnecessary Substance Removal, Carbohydrate Recovery Step Since this step is a step of adjusting the balance of the entire process, various factors at the time of operation are combined, It is preferable to execute by selecting a unit process and an operation rate of the process. The unit process included in this process is described.
Iodine and furfural are recovered from the effluent obtained by condensing the normal pressure steam of the steaming / explosion process of the second step. Iodine is recovered by oxidizing the condensate with, for example, hypochlorite, converting iodine ions into iodine, and depositing iodine completely, followed by steam distillation.

The soluble part 42 in the steaming / explosion process in the second step, the effluent in the hydrolysis step in the fourth step (other than the acid decomposition method), and the effluent in the biofuel concentration step in the sixth step are as necessary. The useful substances are collected separately and / or together.
The heavy metal is recovered using an ion exchange resin.
Natural uranium is adsorbed by passing natural uranium concentrated in alginic acid through a column of tannin adsorbent, and eluted with 0.01 molar hydrochloric acid and recovered.

The fat in the effluent is left to stand for oil-liquid separation or extracted with an organic solvent insoluble in water and recovered.
Alginic acid and fucodyne are collected by acidifying the effluent or by adding a calcium salt to precipitate.
Plant proteins are separated using a semipermeable membrane or adsorbed on an adsorbent. Alginate can also be used as the adsorbent.

After recovering the useful substance from the effluent, if the saccharide has a usable amount and purity, the fermentation inhibitor and the unnecessary substance are removed to recover the saccharide. When the available amount and purity of saccharide is not contained, it is sent to the waste liquid treatment step of the tenth step as an insoluble substance / inhibitor substance liquid.
Since water contains the largest amount as an unnecessary substance in the effluent, concentration is carried out by a reverse osmotic pressure method, a distillation method, or a method using a functional membrane.

The method of collecting carbohydrates in the effluent is
1) Selectively recover using an adsorbent such as hydroxyapatite gel or hydrophilic polymer substance. However, this method is difficult to apply to mass production.
2) The aqueous solution is concentrated and crystallized and collected. As the concentration method, a reverse osmotic pressure method, a distillation method, or a functional membrane can be used. During crystallization, a hydrophilic organic solvent such as ethanol or methanol can be added to promote crystallization.
3) Separation using a semipermeable membrane. In principle, this method is only concentrated and not purified.
In some cases, carbohydrate separation operation is not performed, and useful substances and fermentation-inhibiting substances in the effluent are removed, and a liquid in which the sugar concentration is adjusted is sent as a recovered sugar liquid to the hydrolysis process in the ninth step.
In methods for recovering carbohydrates, it is often difficult to increase the purity of carbohydrates. In the fifth step, it is preferable to increase the conversion rate of the fermentation step using cellulose or / and xylose having high purity so that the sugar recovery step is not required.

(9th process) Sugar hydrolysis process The recovered carbohydrate which processed the soluble part of the cooking / explosion process of the 2nd process, and the discharge | emission liquid of the biofuel concentration of the 6th process at the 8th process is once hydrolyzed. Although it has undergone a decomposition process, it may contain unreacted oligosaccharides. Unless the content of oligosaccharide is negligible by inspection, it is preferable to hydrolyze the recovered carbohydrate solution.
One or more of the soluble part of the steaming / explosion process of the second step, the effluent of the biofuel concentration of the sixth step, and the recovered carbohydrate processed in the eighth step are combined, heated at 180 to 230 ° C., and then atmospheric pressure A monosaccharide solution is obtained by injecting into boiling and quenching to 100 ° C. with heat of evaporation. The monosaccharide solution is sent to the fifth fermentation step.

(10th process) Waste water treatment process The waste liquids of the 2nd to 4th, 6th, 8th and 9th processes are combined and concentrated by membrane filtration to recover biomass. The biomass recovery rate is preferably set to 50 to 80%. If the recovered biomass is burned with a waste liquid recovery boiler to generate power, it is possible to supply more power than the required power of the biofuel production facility.

It is preferable to use a soda recovery boiler as the waste liquid recovery boiler.
A soda recovery boiler is a boiler that recovers and uses energy by using waste liquid discharged in the manufacturing process of a paper mill as fuel. Waste liquid is injected into a boiler furnace and burned, and steam is generated using combustion energy to generate electricity.
After burning, sodium carbonate and sodium sulfide remain in the molten state as residues at the bottom of the furnace. By taking this out and adding quicklime, sodium carbonate can be converted into sodium hydroxide, which can be reused as the treatment material. The treatment agent recovery rate here reaches 98% or more, and there is an effect that a small amount of new treatment agent needs to be replenished.

Moreover, it is preferable to use an extraction back pressure turbine generator as a generator.
The extraction back pressure turbine generator is a turbine generator that can extract steam from the intermediate stage of the turbine and can be used as a factory, and is widely used as a factory generator that requires steam at two or more pressures as factory process steam. It has been. The high-temperature and high-pressure steam supplied to the turbine is taken out at a required pressure, and is a rational turbine that generates electric power according to the amount of use of the steam.

In this case, the temperature and pressure of the steam to be extracted is not necessarily one type, and two or more types of extraction can be performed as necessary to provide factory process steam.
If a bleed back pressure turbine generator is used for power generation in the present invention, the total amount of the two types of high-temperature and high-pressure steam necessary for the second and fourth steps can be supplied from the turbine of the waste liquid recovery process.

In the following, an embodiment of the present invention will be described together with a calculation example showing a substance balance, in which an example of the production of ethanol by cultivating and harvesting hondawald in a 1,000 km ² algae bed set 8 is shown.
(Embodiment)
(A) Honda aquaculture (algae set)
As shown in FIG. 2 (B), the seaweed bed set 8 has 100,000 seaweed bed units 9 aligned and juxtaposed on the sea surface divided by the small waterway 21, the middle waterway 22, and the large waterway 23. Formed.
The seaweed bed set 8 includes 10 management bases 28, a marine biomass transport tanker 30 with a loading capacity of 300,000 tons as a marine biomass transportation means, and 10 medium-sized work vessels 31 with a loading capacity of 600 tons as a harvesting and transportation means. Ten small high-speed seaweed cutter ships 32 and a biofuel production facility 29 installed on land were installed.

The minimum structural unit of the seaweed bed set 8 is the seaweed bed unit 9 shown in FIGS. 2 (C) and (D). The seaweed bed unit 9 has a square net 14 with a side of 100 m that is anchored substantially horizontally below the sea surface to a mooring line 13 that connects the anchor 11 and the buoyant body 12 installed on the seabed 17, A seaweed holding device 15 made of a rope reinforced with a rice bran rope holding the applicator 2 and a net 14 and a seaweed holding device 15 for rising and sinking by increasing or decreasing the volume of gas to be sealed. One buoyancy adjusting device 16.
The depth of settling is 10 m when settling for a long time in winter, and the limit is 20 m even when settling for a short period due to a storm.

(Culture of Honda Walla)
In April, Honda's male and female genital beds were taken out and fertilized. 0.25-0.3 mm embryos were grown in a water tank. The breeding was carried out with light agitation from the bottom of a transparent aquarium, sending air, and agitating the air while moving to a large aquarium with the growth of Honda Walla. From 4 to 6 months after fertilization, the young embryo became a juvenile with a length of 0.5 to 15 mm. In October of the second year, one and a half years after fertilization, it became a Honda Walla at a stem elongation period of about 200 mm in length, so it was transplanted to the algae ground 7 as a seedling. The interval between the seaweed holding devices 15 was 1 m, and 10 honda straw per 1 m was attached at an interval of 10 cm to start aquaculture in the open ocean.

  In winter, the seaweed holding device 15 was submerged to a depth of 10 m and grown. From early spring to summer, when the sea is calm, the seaweed retainer 15 is kept at a depth of 4 m, and the leaves 5 of the upper part of Honda Walla, which is self-floating with air bubbles 6 drifts on the surface of the sea, and the sunlight is sufficient I tried to receive it. Honda Walla grew rapidly and grew to 2-4 m.

(Honda Walla harvest)
In May of the third year, a small cutter boat 32 was used to cut the main branch 4 of the seaweed from the seaweed holding device 15, leaving the applicator 2, stem and 3.
By media work ship 31, the Sargassum floating in clippings by sea harvested else taking strainer inhalation with seawater, thereby, there is harvest 1 m ² per 6.5 kg (dry weight basis) throughout the seagrass beds set 8 Harvested 6.5 million tons of Honda Walla.

(B) Ethanol Production Hereinafter, an ethanol production stage from seaweed harvested according to the flowchart of FIG. 5 will be described.
(First step) Pre-treatment The harvested seaweed is washed with water to remove the adhering components, and pulverized with a fine crusher while heating to 50 to 90 ° C., and neutralized by adding a small amount of sodium hydroxide. The raw material was manufactured. Woody floats such as driftwood, used seaweed holding device 15 and the like were also pulverized into powder and used in addition to the raw materials.

(2nd process) Steaming / explosion process The steaming / explosion apparatus 40 is shown in FIG.
The raw material is preheated by supplying steam from the preheating means 45 in the raw material supply unit 41, then supplied from the pressure inlet 44 to the pressure kettle 43, and 150 ° C in the upper pretreatment unit 48 during the fall. After treating with water vapor 46, it was added to hot water 49 at 120-280 ° C. at the bottom and steamed at 150 ° C. for 5 minutes. The cooked raw material was boiled by being jetted from the adiabatic expansion nozzle 50 to the adiabatic expansion part 54, and rapidly boiled to 100 ° C. with the heat of evaporation and crushed. The produced slurry was separated into a soluble part and an insoluble part by a screw press. In the present example, the liquid condensed with the vapor and the soluble part were sent to the tenth step without recovering useful substances and carbohydrates, and were subjected to waste liquid treatment.

(Third step) Purification step The insoluble part obtained in the second step was washed several times with ethanol, and the washings were combined and concentrated to recover ethanol. The insoluble part was treated with ozone-containing water to decompose the colored substance containing lignin to obtain a cellulose fraction. The effluent from this step was sent to the tenth step.

(Fourth Step) Hydrolysis Step The cellulose fraction obtained in the third step was again used in the steaming / explosion apparatus used in the second step, except that hydrolysis was performed at 230 to 280 ° C. for 5 minutes to obtain a glucose solution. .
(5th process) Ethanol fermentation process The ethanol fermentation was performed at 38 degreeC for 10 hours through the column which added the ethanol fermentation microbe (RITE microbe) which made the glucose solution the living independence.

(6th process) Ethanol concentration process 60-90% ethanol was able to be obtained from the fermentation liquid of the 5th process by the ethanol concentration method which applied the principle of the gate membrane.
(Seventh step) Ethanol drying step Ethanol was passed through a zeolite column to adsorb moisture to obtain 99.5% ethanol.
650 million tons Sargassum (dry weight), ethanol approximately 2 million ^m 2 (2,000,000 kiloliters) was produced.

(Eighth Step) Useful Substance Recovery, Fermentation Inhibitory Substance Removal, Unnecessary Substance Removal, Carbohydrate Recovery Step and (Ninth Step) Sugar Hydrolysis )

(Tenth step) The wastewater treatment steps 2, 4, and 6 were combined and concentrated by membrane filtration to recover biomass. The recovery rate was 65%. This was burned with a waste liquid recovery boiler, and power was generated using a bleed back pressure turbine generator.
The calculation example of the substance and energy balance based on the said embodiment is shown.

1) Yield of Honda Wallet Planting area: 1,000 km ²
Yield per unit area: 6.5 kg / m ² / year Annual yield: 6.5 million tons 2) Biofuel production Cellulose content: 30%
Alginic acid content: 30%
Other carbohydrate content: 28%
12% ash
2-1) Bioethanol production: Manufactured from other carbohydrates Estimated ethanol yield: 289 kg / ton ^{* 1)} ÷ 0.79 (specific gravity)
= 0.356 kiloliters / ton Honda Walla (dry weight)
Ethanol annual production: 650 x 0.58 x 0.365
= 137.6 million kiloliters / year)
(In the case of total allocation: = 207.8 million kiloliters / year)
* 1) Source: (Source: National Institute of Advanced Industrial Science and Technology China Center Biomass Research Center)
Expected value as of 2010 2-2) Biobutanol production Butanol overall yield estimate: 0.88 × 0.80 / 2 = 0.352
Here, saccharification yield = 0.88, fermentation efficiency = 0.90 Assumed butanol yield: 0.352 ÷ 0.81 (specific gravity)
= 0.434 kiloliters / ton (dry weight)
Butanol annual production: 650 × 0.30 × 0.434
= 846,000 kiloliters / year

3) Waste liquid energy recovery (approximate)
Setting conditions:
Combustible residue recovery rate 65%
Boiler efficiency: 0.7
Generator efficiency: 0.35
Hydrocarbon combustion heat: 4,020 Kcal / kg (low heating value)
Molecular weight: carbohydrate / ethanol
= 180 / (46 × 2)
≒ 2
Amount of flammable residue recovered
(650 × 0.88) − (137 × 0.79 × 2)
-(84 x 0.81 x 2 x 0.65)
= 14.3 million tons / year Waste heat recovery boiler calorific value
143 x 4020 x 0.7 x (1,000 / 860)
= 4.68 million MWh / year Generator output
468 × 0.35 × 10 ⁴ / (365 days × 24 hours)
= 189MW

The amount of power generated by waste liquid energy recovery greatly exceeds the total power used by the biofuel manufacturing plant, and can be sold to the outside.
From the cost balance not described, it was estimated that the method for producing biofuel from the seaweed of the present invention was economically established only by the method for producing biofuel described in the examples. Furthermore, it is estimated that sufficient profits can be obtained by collecting useful substances and selling power for waste energy recovery power generation.

It is the schematic of the biochemical reaction path | route regarding the fermentative production of biofuel. It is the schematic which shows a Honda walla. It is the schematic of a seaweed bed, a seaweed bed set, and a seaweed bed unit. It is the schematic of a biofuel manufacturing system. It is a flowchart which shows the outline of the process of manufacturing biofuel. It is a conceptual diagram which shows the cross section of a steaming and detonation apparatus. It is a conceptual diagram which shows the cross section of the steaming and detonation apparatus equipped with the expansion turbine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Seaweed 2 Adhering device 3 Stem 4 Main branch 5 Leaf 6 Air vesicle 7 Algae field 8 Algae field set 9 Algae field unit 11 Anchor 12 Buoyant body 13 Mooring line 14 Net 15 Seaweed holding device 16 Buoyancy control device 17 Sea bottom 18 Sea surface 21 Small waterway 22 Middle Waterway 23 Large Waterway 24 Channel 25 Fishing Ground 26 Management Center 27 Marine Satellite System 28 Management Base 29 Biofuel Production Equipment 30 Marine Biomass Transport Tanker 31 Medium Work Ship 32 Small High-Speed Seaweed Cutter Boat 40 Steaming and Detonation Equipment 41 Raw Material Supply Part 42 steaming part 43 pressure kettle 44 pressure inlet 45 preheating means 46 steam 47 piping 48 pretreatment part 49 hot water 50 adiabatic expansion nozzle 51 atmospheric pressure steam outlet 52 soluble part outlet 53 solid-liquid separation device 54 adiabatic expansion part 55 Expansion turbine 56 Expansion turbine outlet

Claims (13)

Marine biomass is a perennial seaweed that becomes self-floating with air bubbles,
(1) A marine biomass harvesting stage for harvesting by harvesting the main branch leaving the seaweed attachment and stem after the seaweed has matured;
(2) A pre-treatment stage for chopping and pulverizing the harvested marine biomass, and suspending the chopped and crushed marine biomass in hot water at 120 to 280 ° C., and then ejecting it to atmospheric pressure to bring it to a boil , A steaming / explosion stage that is rapidly cooled to 100 ° C. by heat of evaporation, a cellulose fraction purification stage that collects an insoluble part from the product of the steaming / explosion stage and purifies it to obtain a cellulose fraction, and 120 parts of the cellulose fraction. A biofuel production stage comprising: a hydrolyzing stage in addition to hot water of ˜280 ° C., followed by jetting into the atmospheric pressure to boil and quenching to 100 ° C. with the heat of evaporation to produce a glucose solution;
A biofuel production method comprising:   The cellulose fraction purification step is a step of collecting the cellulose fraction by treating the insoluble part with one or more treatment agents consisting of ozone, sodium hydroxide and sodium carbonate. The biofuel production method according to claim 1.   A saccharide recovery stage in which soluble parts are collected from the product of the steaming / explosion stage and the saccharide is recovered, and the recovered saccharide is added to hot water at 120 to 280 ° C., and then blown into atmospheric pressure. The method for producing biofuel according to claim 1, further comprising: a carbohydrate hydrolysis step in which a monosaccharide solution is produced by boiling and rapidly cooling to 100 ° C. with heat of evaporation.   A fermentation stage for obtaining a fermentation broth by fermenting the glucose solution; a collection stage for collecting a crude biofuel from the fermentation broth; and a biofuel purification stage for refining the crude biofuel. The biofuel manufacturing method according to claim 1.   A biofuel production step comprising: a reduction step of producing a sugar alcohol by reducing the glucose solution; and a hydrocracking step of producing ethylene from the sugar alcohol using a fluidized bed hydrocracking catalyst. The biofuel production method according to claim 1.   A fermentation stage for obtaining a fermentation broth by fermenting the monosaccharide solution; a collection stage for collecting crude biofuel from the fermentation broth; and a biofuel purification stage for refining the crude biofuel. The biofuel production method according to claim 3.   A biofuel production step comprising: a reduction step of producing a sugar alcohol by reducing the monosaccharide solution; and a hydrocracking step of producing ethylene from the sugar alcohol using a fluidized bed hydrocracking catalyst. The biofuel production method according to claim 3, wherein   A waste liquid recovery stage in which one or more of the effluents generated in each stage of the biofuel production stage are combined to recover organic matter, and the organic matter is combusted in a waste liquid recovery boiler, and power is generated using steam generated in the waste liquid recovery boiler. The method for producing biofuel according to any one of claims 1 to 7, further comprising: a power generation stage.   Using an extraction back pressure turbine generator in the power generation stage to generate power and supply steam to one or more of the steaming / explosion stage, the hydrolysis stage, and the carbohydrate hydrolysis stage. The biofuel production method according to claim 8, wherein   The method for producing biofuel according to claim 1, wherein the seaweed is a seaweed belonging to the order of the scorpionidae. Marine biomass is a perennial seaweed that becomes self-floating with air bubbles,
(1) A seaweed holding device for holding the seaweed attachment device and a buoyancy adjusting device for floating and sinking the seaweed holding device, and a net connected to a mooring line connecting an anchor and a buoyant body installed on the seabed A seaweed bed unit attached substantially horizontally, a seaweed bed set in which a plurality of the seaweed bed units are aligned and gathered at a predetermined interval, and a plurality of algae beds set at predetermined intervals. A marine biomass harvesting means comprising: a farming means, and a harvesting means for cutting and harvesting the main branches leaving the seaweed attachment and stems;
(2) biofuel production means;
A biofuel production apparatus comprising: The biofuel production means comprises
Pretreatment means for shredding and crushing harvested marine biomass, and suspending the shredded and crushed marine biomass in hot water at 120 to 280 ° C, then ejecting it to atmospheric pressure to boil, and evaporating heat Cooking / explosion means for rapid cooling to 100 ° C., cellulose fraction purification means for collecting an insoluble part from the product of the steaming / explosion means and collecting the cellulose fraction, and the cellulose fraction for 120 to 280 In addition to hot water at ℃, then boiled and boiled into atmospheric pressure, rapidly hydrolyzed to 100 ℃ with the heat of evaporation to produce a glucose solution, and fermentation to obtain a fermentation broth by fermenting the glucose solution Means, a collecting means for collecting the crude biofuel from the fermentation broth, a biofuel purification means for purifying the crude biofuel, and one or more of the effluents produced in each of the means The waste liquid recovery means for recovering the organic matter, and the power generation means for combusting the organic matter with the waste liquid recovery boiler and generating electric power using the steam generated in the waste liquid recovery boiler. Biofuel production equipment.   The biofuel production apparatus according to claim 10, wherein the power generation means is a bleed back pressure turbine generator.

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