JP2008253861A - Continuous high pressure hydrothermal reaction apparatus for treating biomass - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an efficient continuous high pressure hydrothermal reaction apparatus and its control method for treating biomass for the purpose of separating the constituent components of the biomass. <P>SOLUTION: The continuous high pressure hydrothermal reaction apparatus is composed of a material supply device constituted of a slurry pump and a solvent supply pump capable of controlling a material grinding kneader and a material transport speed, a tubular reaction pipe, which comprises a corrosion-resistant metal, controlled in temperature by a plurality of stages of temperature raising heaters, thermostatic heaters and water cooling type cooling pipes and a material discharge device constituted of a duplex electromagnetic shutter valve placed centering around a pressure buffer chamber and constituted so as to apply a severely controlled high pressure hydrothermal reaction condition to the biomass in the tubular reaction pipe. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to the recycling of resources discharged from agriculture, fermentation brewing, food processing industries, and the like, and technology for converting generated materials into medicines, foods, industrial materials, and energy resources.

  In general, acid hydrolysis, enzymatic hydrolysis, and microbial decomposition methods are known as methods of using biomass and cellulose or hemicellulose as food and energy resources by hydrolyzing and saccharifying them. . As a relatively new method, there has been proposed a method of producing monosaccharides by allowing water in a supercritical state or a subcritical state to act on cellulose to hydrolyze it. The technology aimed at improving the yield of decomposition and commercialization includes contacting cellulose powder with 240-280 ° C pressurized hot water to hydrolyze, and then rapidly cooling to produce cellooligosaccharides. Water-soluble impurities by producing monosaccharides in high yield by enzymatic decomposition of the product (Patent No. 3041380) or by hydrothermal treatment at 110-140 ° C using xylan-containing natural sugarcane bis as a starting material A method of producing xylose and xylo-oligosaccharide by removing hot water at 200 ° C. or less after removing insoluble residue (Japanese Patent Laid-Open No. 2000-236899) is known. In addition, a method has been invented for separating biomass components by combining a biomass resource with a cell treatment process using basidiomycetes and decaying fungi and a high-pressure hydrothermal reaction process at 160-230 ° C and 0.5-10 MPa (specialty). No. 2005-27541).

Japanese Patent No. 3041380 JP 2000-236899 A JP 2005-27541 A

  When an acid catalyst is allowed to act on wood resources using conventional acid hydrolysis methods, the acid catalyst affects not only cellulose and hemicellulose, but also monosaccharides and lignin, and byproducts such as furfural that inhibit fermentation are generated. In addition, since lignin undergoes chemical modification and causes self-polymerization, there is a problem that it is difficult to industrially use the product. In addition, there is a problem in that the operation of an acid-resistant plant and the recovery of acid require an industrial cost and a heavy load on the environment.

  On the other hand, enzymatic hydrolysis is an effective method that allows hydrolysis to proceed under mild conditions without the production of by-products that inhibit fermentation. However, it is possible to combine cellulose with hemicellulose or lignin, cellulose Since it takes time to break hydrogen bonds between molecular chains, there is a disadvantage that the saccharification rate is extremely slow. In order to increase the reaction rate, pretreatment such as blasting and grinding is necessary for the starting material, and there is a problem that industrial costs are required in conjunction with mass production of enzymes and establishment of a recovery system.

  The method of hydrolyzing supercritical water and subcritical water on cellulose to obtain monosaccharides has the advantage of a high reaction rate, but if controlled incorrectly, a large amount of by-products such as furfural is generated and the yield is increased. There is a problem that the industrial use of the product is significantly restricted as well as being lowered. In the case of a large-scale plant, a corrosion-resistant high-pressure reactor lined with a special alloy that can withstand the temperature, pressure, and oxidizing power in the supercritical region of water (critical point: 374 ° C, 22.1 MPa) is required.

  In the method of Patent No. 3041380 devised to solve the above-mentioned problem of supercritical water treatment, after applying pressurized hot water of 240 to 280 ° C. to cellulose, the enzyme is allowed to act on the optimum conditions. While suppressing the generation of by-products, cellooligosaccharide and glucose, which is a hydrolyzed monosaccharide thereof, can be obtained in a high yield exceeding 90%. However, this method uses industrially purified crystalline cellulose as a starting material, so when applied to woody resources that have a structure in which cellulose is embedded in lignin via hemicellulose in the plant cell wall. The presence of lignin and hemicellulose cannot be ignored and it is difficult to obtain a similar yield.

  On the other hand, hot water treatment at 110-140 ° C is performed using xylan-containing natural product sugarcane bis as a starting material to remove water-soluble impurities, and hot water at 200 ° C or less is allowed to act on insoluble residues to produce xylose and xylooligosaccharides. The method of Japanese Patent Application Laid-Open No. 2000-236899 is a relatively efficient method that facilitates the subsequent purification and decolorization step and purifies high-purity xylo-oligosaccharides, but the heat treatment time in the hydrolysis step is 150 to 160 ° C. 60 to 90 minutes, and the yield estimated from the examples of the specification is about 21 to 35%.

  As a method for solving the above problems relatively well, Japanese Patent Application Laid-Open No. 2005-27541 discloses a biomass treatment process using basidiomycetes and decaying fungi and a high-pressure hydrothermal reaction treatment process at 160-230 ° C. and 0.5-10 MPa. Has been invented in a manner to separate the biomass components. However, in this embodiment of the invention, the biomass material is charged into a pressure-resistant tank equipped with a stirrer, and the material is fed into the reaction tube by pumping water with a pressure pump, and on the material discharge side after the hydrothermal reaction, a filter is used. It has a system configuration in which a solid-liquid separator is made. In this system, the concentration of biomass sent to the reaction tube decreases over time, and in biomass processing, a large amount of solids is generated, causing clogging of the filter, making it difficult to keep the flow rate and pressure in the reaction tube constant. Therefore, continuous processing for a long time is difficult, and practicality and maintenance are poor.

  An object of the present invention is to obtain an efficient continuous hydrothermal reactor for biomass treatment and a control method thereof.

In a continuous high-pressure hydrothermal reactor that separates components of biomass as useful resources, a material supply device composed of a material crusher kneader, a slurry pump capable of controlling the material transport rate, and a solvent supply pump, and a multi-stage temperature increase It consists of a heater, a constant temperature heater, a tube-type reaction tube composed of a corrosion-resistant metal whose temperature is controlled by a water-cooled cooling tube, and a material discharge device composed of a series of electromagnetic shutter valves centered on a pressure buffer chamber. The biomass is subjected to strictly controlled high-pressure hydrothermal reaction conditions in a tube-type reaction tube.

A warm water washing process of 40 to 80 ° C. is arranged for the biomass material between the material crushing and the material supplying process.

The diameter of the reaction tube of the tube type reaction tube is 15 to 50 mm, the inclination angle is 4 to 30 degrees, and the material supply device is arranged at a position higher than the material discharge device, and the material flows along the gravity from above.

In order to control the flow by preventing the sedimentation of the biomass material, a spiral groove is formed in the tube type reaction tube. It also gives mechanical vibration to the tube.

  The temperature raising heater is configured and controlled by at least two temperature blocks.

A hydrothermal reaction is applied to corn-cobb biomass in a reaction tube at 160 to 230 ° C., 0.5 to 5 MPa, and 5 to 20 minutes.

Instead of a tube-type reaction tube, the shape of the reaction tube is dug into a metal mold that incorporates an electric heater, and the function of dividing the tube into right and left is given.

A continuous high-pressure hydrothermal reactor that separates components of biomass as useful resources, a material supply kneader, a slurry pump that can control the material transport speed, a material supply device composed of a solvent supply pump, and a multi-stage Material discharge device composed of temperature rising heater, constant temperature heater and tube type reaction tube made of corrosion-resistant metal whose temperature is controlled by water cooling type cooling tube and double electromagnetic shutter valve centered on pressure buffer chamber By systematizing the system, it becomes possible to strictly control the temperature, time, and pressure, which are the optimal conditions for hydrothermal reaction for component separation, and the generation of harmful impurities such as acids and furals in the processing liquid is suppressed. The effect of improving the recovery rate is obtained.

By disposing a 40 to 80 ° C. warm water washing step on the biomass material between the material crushing and the material supplying step, protein-based impurities contained in the biomass are removed, and purification of the treatment liquid becomes easy.

The diameter of the reaction tube of the tube-type reaction tube of the continuous high-pressure hydrothermal reactor is 15 to 50 mm, the inclination angle is 4 to 30 degrees, and the material supply device is placed at a higher position than the material discharge device, so that the slurry is at the top of the device. It flows more along the gravity, the sedimentation of the biomass component in the slurry in the reaction tube is suppressed, the device can be operated continuously, and the component recovery rate is improved.

In order to control the flow by preventing sedimentation of the biomass material, a spiral groove is formed in the tube-type reaction tube, or mechanical vibration is applied to the reaction tube, so that the biomass components in the slurry in the reaction tube are settled. Is suppressed, the apparatus can be operated continuously, and the component recovery rate is improved.

  By configuring and controlling the temperature raising heater with at least two stages of temperature blocks, the internal temperature distribution becomes constant when the biomass slurry is introduced into the reaction tube, and the temperature condition of the hydrothermal reaction optimal for component separation is Since it stabilizes, the effect that a component recovery rate improves is acquired.

By applying continuous high-pressure hydrothermal reaction to corn cob biomass in a reaction tube at 160 to 230 ° C, 0.5 to 5 MPa, and 5 to 20 minutes, generation of harmful impurities such as acids and fouling is suppressed. It is possible to recover the hemicellulose component contained in 100% as xylose and hemicellulose.

By digging the shape of the reaction tube into a metal mold that incorporates an electric heater instead of the tube reaction tube, and adding the function to divide the tube into left and right, the biomass components burned out during continuous operation are removed with a wire brush etc. It becomes possible to perform maintenance, and maintenance becomes easy, and it becomes possible to always reproduce a stable hydrothermal reaction.

  Biomass, which is a natural resource, is characterized in that its properties and components are not constant, and it is poor in stability as a material due to the production area, growing conditions, seasonal climatic factors, and the like. Even when such biomass is slurried and fed into a hydrothermal reaction tube, the biomass components do not settle in the tube, and the temperature, time, and pressure, which are the optimal conditions for hydrothermal reaction, are strict. The best form cannot be obtained unless it is given. In addition to the fact that corrosion is not generated in the hydrothermal reaction tube so that stable continuous operation can be performed over a long period of time, maintenance is easy, and no harmful impurities such as acid and fouling are generated in the treatment liquid. A high component recovery rate is a requirement for a continuous high-pressure hydrothermal reaction system.

In order to design a continuous high-pressure hydrothermal reactor for biomass that satisfies the above conditions in the studies so far, a material composed of a material crusher kneader, a slurry pump capable of controlling the material transport speed, and a solvent supply pump Two electromagnetic shutter valves centered on a supply device, a tube-type reaction tube and a pressure buffer chamber made of corrosion-resistant metal whose temperature is controlled by a multi-stage heating heater, constant temperature heater and water-cooled cooling pipe It was best to combine the material discharge device constituted by as a system.

An outline of the devised continuous high-pressure hydrothermal reactor will be described with reference to the drawings. FIG. 1 is a system diagram of this apparatus. The apparatus includes a material supply device 1, a tube-type reaction tube 2, and a material discharge device 3. Biomass sent to the material supply apparatus 1 is sent to the material crushing kneader 4, wet-ground by adding an appropriate amount of water, and introduced into the slurry pump 5. A mechanism for stirring the material immediately before the introduction of the pump is provided so that the biomass component does not settle in the slurry. The slurry having a uniform concentration by such a stirring mechanism is introduced into the tubular reaction tube 2 by the slurry pump 5 at a constant transport speed. From a solvent tank 6 provided separately from this system, a cylinder solvent supply pump 7 can add a solvent such as water to the biomass slurry transported by the slurry pump 5 immediately before the reaction tube 2.

The next tube-type reaction tube is composed of a heating heater 8 having a six-stage temperature block, a constant temperature heater 9 and a water-cooling cooling tube 10. The water 11 was supplied to the cooling pipe as shown in the figure, and stainless steel was used as the corrosion resistant metal of the reaction pipe.

The material discharging apparatus is composed of two electromagnetic shutter valves 12 and a pressure buffer chamber 13, and the biomass slurry is sent to the final treatment liquid tank 14 together with the solid liquid. The pressure buffer chamber 13 has a mechanism for supplying air 15 so that a constant air pressure is applied to the pipe between the valves when the two shutter valves 12 are alternately opened and closed, and the discharge of the biomass slurry is promoted. This material discharge device is manufactured by Kimura Chemical Co., Ltd., and has the same principle as the discharge mechanism described in the company's invention “pressure control mechanism of slurry liquid high-temperature and high-pressure reaction treatment system” (Japanese Patent Laid-Open No. 11-226385). .

A process of washing biomass with warm water of 40 to 80 ° C. is arranged between the material crushing and the material supplying process. This process removes impurities such as proteins, amino acids, and organic acids contained in the biomass before the high-pressure hydrothermal reaction, greatly reducing the production of coloring substances generated during the high-pressure hydrothermal reaction, The purification of was easier. Moreover, the Maillard reaction by the saccharide | sugar and protein which generate | occur | produce at the time of a high pressure hydrothermal reaction was suppressed, and the yield of the collect | recovered saccharide | sugar component improved. When the waste medium used for enokitake mushroom cultivation as corn cob biomass is used as the starting material, the effect of removing impurities is low when the treatment temperature is less than 40 ° C, and about 80% of the solubilized fraction is removed by washing with warm water above 40 ° C. 90% or more of the solubilized fraction was removed by washing with warm water at 60 ° C. or higher. Moreover, the effect of energy was not seen even if the temperature of 80 degreeC or more was given.

Regarding the design of the tube-type reaction tube 2 of the continuous high-pressure hydrothermal reactor, the diameter of the reaction tube is 15 to 50 mm, the inclination angle is 4 to 30 degrees, and the material supply device can be arranged at a higher position than the material discharge device. This is the best mode for carrying out the invention. When the diameter of the reaction tube was 15 mm or less, the reaction tube was blocked by the biomass slurry, and excessive pressure was applied to the slurry pump, making control difficult. On the other hand, if the diameter of the reaction tube is designed to be 50 mm or more, sedimentation tends to occur in the biomass slurry, temperature distribution occurs in the reaction tube, and there are cases where the thermal energy applied to the biomass material is insufficient, or the reaction occurs due to an exothermic reaction. In some cases, such as runaway and excessive temperature, control became extremely difficult.

It is effective to suppress the sedimentation of biomass material in the slurry in the reaction tube by applying a spiral groove-like process in the tube-type reaction tube 2 and applying mechanical vibration to the reaction tube by a vibrator. Met.

  It was best to configure and control the temperature raising heater 8 with at least two temperature blocks. Without the temperature raising heater 8, it was difficult to form a stable temperature in the hydrothermal reaction tube.

A component separation experiment was conducted using the waste medium used for enokitake cultivation as corn cob biomass. Hemicellulose component contained in corn cob is controlled by giving hydrothermal reaction at a temperature of 160-230 ° C, pressure of 0.5-5MPa, and reaction time of 5-20min. It was possible to recover almost 100% as xylose and hemicellulose. The conditions with the best yield were 190 ° C., 1.8 MPa, and 10 minutes. When the reaction under the above conditions is deviated to a gentle side, the yield is lowered, and when the reaction is deviated to an excessive side, the amount of fural produced is increased and the yield is lowered.

In the tube-type reaction tube 2 of FIG. 1, a stainless seamless tube is used, but instead of this, a reaction tube shape 17 is provided in a stainless steel mold 16 incorporating a temperature raising heater 8 and a constant temperature heater 9 as shown in FIG. When digging and performing a continuous hydrothermal reaction, the temperature in the reaction tube is stabilized by the heat capacity of the mold, and the mold is divided every time the equipment is stopped, and biomass components burned during continuous operation are removed with a wire brush etc. As a result, maintenance was dramatically improved and production was stabilized. In addition, a heat insulating material 18 was provided between the blocks so that the set temperatures of the temperature raising heater 8, the constant temperature heater 9, and the water-cooled cooling pipe 10 in the mold 16 do not affect the blocks.

  Embodiments of the present invention will be described with reference to the drawings. The continuous high pressure hydrothermal reactor shown in FIG. 1 was manufactured so as to obtain the best mode for carrying out the present invention. A mass collider is disposed in the material crusher kneader 4 of the material supply apparatus 1, and a monoscrew pump including a stainless spindle and a hard rubber cavity is disposed in the slurry pump 5 of the slurry supply portion. The discharge pressure at this time was designed to be a maximum of 3.0 MPa and the maximum discharge capacity was 300 cc / min. The solvent supply pump 7 is a diaphragm type, made of stainless steel and Teflon (registered trademark), discharge rate of 300 cc / min, and discharge pressure of 3.0 MPa at maximum. The capacity of the temperature raising part of the tube-type reaction tube 2 was 0.8 L, the reaction tube diameter was 25.4 mm, and the length was 2 m. The constant-temperature reactor has a capacity of 3.6L, a reaction tube diameter of 25.4mm, and a length of 2m, and 4 stages of 200V / 1.0kW super seed heaters. The water-cooled cooling pipe has a double-tube configuration with a capacity of 1.6L. The design temperature of the reaction tube was 230 ° C., and the design pressure was 3 MPa.

  The waste medium after enokitake cultivation produced in Nagano Prefecture was selected as the biomass material. The medium for enokitake mushroom cultivation is mainly composed of corn cob and rice bran and bran-derived components, and in addition, carbohydrates and protein components derived from enokitake mushroom cells. The component composition of the biomass at the time of carrying out the present invention was 18.75% lignin, 22.89% cellulose, 36.08% hemicellulose, and 20.67% as a warm water solubilized fraction of proteins and amino acids.

The waste medium and water selected in the material crusher kneader 4 of the continuous high-pressure hydrothermal reactor are added, pulverized to a particle size of 1 mm or less, washed with warm water at 60 ° C, dehydrated by centrifugation, and the solids concentration is 12 to 14 % Slurry was formed and introduced into the tube-type reaction tube 2 via the slurry pump 5.

  As for the setting on the apparatus side, a set temperature of the constant temperature heater 9 of the reaction tube was 200 ° C., and a ramp temperature from 20 ° C. to 200 ° C. was given to the six stages of the temperature rising tube heater. The material discharge device 14 controlled the pressure in the reaction tube to 1.79-1.81 MPa by setting the electromagnetic shutter valve 12 to an opening time of 0.15 seconds and a double valve opening / closing time lag of 0.5 seconds. At this time, the actual temperature of the slurry in the reaction tube is 190 ± 10 ° C, the reaction tube passage time, that is, the hydrothermal reaction time is 10 minutes, and the slurry temperature at the outlet temperature of the water-cooled cooling tube 10 is 50 ° C. It was.

  The liquid obtained by the continuous reaction was collected in the treatment liquid tank 14, and the obtained slurry was subjected to solid-liquid separation by centrifugation. The solid content obtained here was sterilized, desalted, and concentrated with Kyowa Hakko's enzyme preparation doriserase derived from basidiomycete Irpex lacteus, dissolved in 0.02 M, pH = 5.0 sodium acetate buffer solution, A fraction having a cellulase and xylanase activity and having a molecular weight of 10,000 or more was used, and a reaction was given for 24 hours under the conditions of an enzyme concentration of 0.1% w / v, pH = 5.0, and 30 ° C. 60.24% of biomass components were recovered as primary water-soluble components by high-pressure hydrothermal reaction. Moreover, 17.10% of the biomass components were recovered as glucose and cellooligosaccharide by enzymatic decomposition. While the final solid residue of 22.66% was recovered as lignin without chemical modification, in this example, the occurrence of fouling was slight.

When the primary water-soluble component by high-pressure hydrothermal reaction was subjected to acid treatment and decomposed into constituent sugars to analyze the main sugar composition, glucose: xylose: galactose: L-arabinose = 8.2: 69.9: 5.9: 16.0. On the other hand, according to a previous report, the xylan of corn cob is arabinoxylan, and the ratio of xylose to arabinose is 3 to 4 to 1, the composition of this time is consistent with this example, and about 86% in the solubilized solution is derived from xylan I knew that there was. Therefore, when HPLC and MALDI TOFMS analysis were performed in order to see the molecular weight distribution of the xylan decomposition product, xylooligosaccharides having a wide molecular weight distribution were included. There was also a polysaccharide fraction with a degree of polymerization of 10-15.

In order to verify the effect of arranging the hot water washing step between the material grinding and the material supply, the waste medium was processed without arranging the hot water washing step. When the treatment liquid obtained by arranging the hot water washing process was compared with the treatment liquid obtained without arrangement, the recovered xylooligosaccharide increased by 39%, the coloring substance decreased by 37%, and the ionic substance 24% decrease.

  As described above, according to the present invention, the temperature, time, and pressure, which are the conditions of the hydrothermal reaction optimum for component separation, were strictly given to the biomass whose components are not stable. In addition, stable continuous operation over a long period of 5 days is possible, corrosion does not occur in the hydrothermal reaction tube, and no harmful impurities such as acid and fouling are generated in the processing solution, which is extremely ideal. It was possible to recover the components.

  As described above, according to the present invention, cellulose, hemicellulose, and lignin components can be separated by giving precise reaction energy to biomass resources without using special plant materials or chemicals with high environmental impact such as strong acids. . In addition, monosaccharides such as glucose and xylose, cellooligosaccharides, xylooligosaccharides, and non-chemically modified lignin can be efficiently separated and produced without generating fermentation inhibition byproducts such as furfural. This makes it possible to use resources discharged from agriculture, the fermentation brewing industry, etc., and to use the resulting materials for medicines, foods, industrial materials, and energy resources.

Diagram showing outline of continuous high-pressure hydrothermal reactor Diagram showing application example of tube-type reaction tube

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Material supply apparatus 2 Tube type reaction tube 3 Material discharge | emission apparatus 4 Material grinding | pulverization kneader 5 Slurry pump 6 Solvent tank 7 Solvent supply pump 8 Temperature rising heater 9 Constant temperature heater 10 Water cooling type cooling pipe 11 Water 12 Electromagnetic shutter valve 13 Pressure buffer chamber 14 Treatment liquid tank 15 Air 16 Stainless steel mold 17 Reaction tube shape 18 Heat insulating material

Claims (7)

In a hydrothermal reactor that separates components of biomass as useful resources, a material supply device comprising a material crusher kneader, a slurry pump capable of controlling the material transport rate, and a solvent supply pump, a multi-stage heating heater, and a constant temperature Tube reaction consisting of a tube-type reaction tube composed of a corrosion-resistant metal whose temperature is controlled by a heater and a water-cooled cooling tube and a material discharge device composed of two electromagnetic shutter valves centered on a pressure buffer chamber A continuous high-pressure hydrothermal reactor characterized by giving strictly controlled high-pressure hydrothermal reaction conditions to biomass in a tube. The biomass treatment method using a continuous high-pressure hydrothermal reactor according to claim 1, wherein a hot water washing step of 40 to 80 ° C is arranged for the biomass material between the material grinding and the material supply. In order to control the flow by preventing sedimentation of the biomass material, the material supply device is positioned higher than the material discharge device so that the inclination angle of the tube type reaction tube is 4 to 30 degrees and the diameter of the reaction tube is 15 to 50 mm. The biomass processing method using a continuous high-pressure hydrothermal reactor according to claim 1, wherein the material is caused to flow along the gravity from above. 2. A continuous high-pressure hydrothermal reactor according to claim 1, wherein a spiral groove is formed in the tube-type reaction tube and sonic vibration is applied to the tube in order to control the flow by preventing sedimentation of the biomass material. Biomass processing method. The method for treating biomass by a continuous high-pressure hydrothermal reactor according to claim 1, wherein the temperature raising heater is controlled by at least two temperature blocks. Condensation of hemicellulose component, non-crystalline cellulose component, crystalline cellulose and lignin component by giving hydrothermal reaction to corn-cobb biomass in a reaction tube at 160-230 ° C, 0.5-5MPa, 5-20min The biomass treatment method for a continuous high-pressure hydrothermal reactor according to claim 1, wherein the biomass is separated. 2. The continuous high-pressure hydrothermal reactor according to claim 1, which has a function of digging the shape of a reaction tube into a metal mold incorporating an electric heater in place of the tube reaction tube and dividing the tube into left and right.

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