JP5503282B2 - Continuous pressurized hot water treatment method for biomass materials - Google Patents

Description

  The present invention relates to a continuous pressurized hot water treatment method for a biomass material for improving the saccharification treatment efficiency of a biomass material containing cellulose, hemicellulose, and lignin.

  In recent years, fuels made from plants that replace petroleum, which is a limited resource, have attracted attention, and in particular, fuels that use non-edible plants such as trees and herbs that do not cause food problems have attracted attention. In order to use the plant as a fuel, it is necessary to saccharify cellulose and hemicellulose contained in the plant to obtain sugar, and then perform alcoholic fermentation to obtain a fuel such as ethanol. However, since cellulose and hemicellulose are embedded in lignin contained in plants, they are not saccharified even if they are saccharified as they are. Therefore, it is necessary to increase the efficiency of the saccharification treatment by some pretreatment.

  Non-Patent Document 1 describes a method of increasing the saccharification rate by a steaming / explosion method used as a method for producing oligosaccharides. In this method, a raw material chip is placed in a pressure cooker, cooked for a short time at high temperature and high pressure, and then the pressure is suddenly released. Exposure to high temperature conditions such as 200-240 ° C. for a short time will form acid and lower the pH to about 3. And it is the method of causing hydrolysis by the acid. In addition, the rapid decompression destroys the cell membrane and partially destroys lignin. However, this method is batch-type and takes time to raise the pressure kettle, which is disadvantageous in terms of productivity, and it is difficult to shorten the residence time, so that overdecomposition is inevitable. is there.

  Non-Patent Document 1 also describes a continuous saccharification system of cellulose that performs chemical treatment simultaneously with explosion using a twin screw extruder. That is, cellulosic waste is subdivided with a twin screw extruder for plastic processing, excess water is removed, the slurry is heated to 243 ° C., a pressure of 500 psi is applied, and 0.5% sulfuric acid is injected just before being extruded. This is a process of hydrolyzing instantaneously, opening a pressure-removing valve provided at the tip of the extruder, and quickly discharging and cooling 20 seconds later. However, although this method is also referred to as a continuous method, it is substantially a batch method, which is disadvantageous in terms of productivity, and the residence time is not constant, so that a homogeneous material cannot be obtained. There is.

  Patent Document 1 discloses that a high-pressure reactor that treats an object to be processed containing lignin containing 10% by mass or more of water under high pressure suppresses the backflow of the high-pressure atmosphere from the high-pressure reactor continuously. A screw feeder is provided to supply an object to be processed. The screw feeder is provided with a workpiece supply unit on one end side and a discharge port on the other end side. A high-pressure atmosphere connected to the discharge port of the screw feeder and forming a high-pressure atmosphere pressurized to a pressure of 2 MPa or more, by a sealing action by deposits compressed at the other end of the screw feeder An invention is disclosed in which a mechanical valve capable of adjusting a gap is installed at the tip to supply an object to be processed so that airtightness between the screw and one end of the screw feeder is maintained. However, in this method, there is a problem that processing such as pulverization of the material after pressure treatment by one extruder, adjustment of water content, and adjustment of temperature cannot be performed.

  In general, as a method of increasing the cylinder internal pressure of an extruder for processing a molten resin, a method of increasing the pressure by providing a resistor in the cylinder and allowing a fluid having high viscosity to pass through the resistor is employed. For example, in Patent Document 2, a waste resin material mainly composed of a thermosetting resin-based coating film and a thermoplastic resin is supplied to a cylinder, while being fed from an upstream side to a downstream side by a feeding means while being melted, The resin material is hydrolyzed by bringing the resin material into contact with water or water vapor in the hydrolysis region of the cylinder. At that time, a seal ring that functions as a resistor is disposed in the passage, and the high-filling region is formed by suppressing the feeding of the resin material downstream in the hydrolysis region, thereby preventing the early removal of water and water vapor. . At the same time, the pressure is set to 980 to 9800 kPa and the resin temperature is set to 180 to 280 ° C. to improve the contact efficiency between the resin material and the hydrolyzing agent in the cylinder, and effectively reduce the molecular weight by hydrolysis of the thermosetting resin. Further, an invention relating to a method and an apparatus for recycling resin waste that can contribute to shortening the regeneration treatment time and improving the quality of the recycled resin composition is disclosed. However, this method is effective only for a material having a resin, and there is a problem that it is impossible to keep the pressure constant when applied to a biomass material.

WO2004 / 105927 JP 7-124945 A

Junichi Higashi, Tetsuo Koshijima; Wood Research and Materials, No. 17, P1-20 (1983)

  In the method of continuously treating a lignin-containing biomass material with a pressurized hot water treatment at 100 ° C. or higher, the pressure of the pressurized hot water treatment section of the screw extruder is maintained above the pressure at which the pressurized hot water is maintained. An object of the present invention is to provide a continuous pressurized hot water treatment method for a biomass material that can be pressurized.

In order to achieve the above-mentioned object, the continuous pressurized hot water treatment method for biomass material of the present invention is such that a biomass material containing lignin is continuously heated to 100 ° C. or higher by a screw extruder having a pressurized hot water treatment section. In the continuous pressurized hot water treatment method for performing pressurized hot water treatment, the pressurized hot water treatment part is provided with an upstream seal part on the upstream side and a downstream seal part on the downstream side, and an upstream part of the downstream seal part A liquid addition nozzle for supplying a liquid component for cooling the biomass material, adding the liquid component from the liquid addition nozzle to the biomass material, and determining the temperature of the biomass material in the downstream seal portion by cooling to below the boiling point of the liquid component contained within the liquid component contained in the biomass material in the downstream sealing portion be present in a liquid state, said downstream Sea Characterized in that to increase the coercive pressure capability parts.

  The pressurized hot water treatment unit is characterized in that the pressurized hot water treatment is performed at a pressure of 0.27 MPa (saturated vapor pressure of water at 130 ° C.) or higher and a temperature of the biomass material of 130 ° C. or higher.

The biomass material in the downstream seal portion is cooled by adding liquid water to the biomass material in the upstream portion of the downstream seal portion.

  Further, the biomass material in the downstream seal portion is cooled by cooling the vicinity of the downstream seal portion in the screw extruder by a cooling means.

  In the processing method of pressurized hot water treatment of biomass material containing lignin, in order to keep the pressure of the pressurized hot water treatment unit higher than the pressure to maintain the pressurized hot water, downstream of the pressurized hot water treatment unit By cooling the temperature of the biomass material of the installed downstream seal part below the boiling point of the liquid component such as moisture contained in the system, the liquid component such as water contained in the biomass material is present as a liquid, Increase the pressure holding capacity of the seal part. As a result, the biomass material containing lignin can be continuously subjected to pressurized hot water treatment at a constant pressure and temperature.

It is explanatory drawing which shows an example of the screw extruder used in order to implement this invention.

  As shown in FIG. 1, the screw extruder E includes a cylinder 1 in which a long hopper cylinder 2 as a supply unit is incorporated at one end side, a screw (not shown) rotatably disposed in the cylinder 1, The motor 14 and the speed reducer 15 which comprise the rotational drive means for rotating a screw are provided.

  On the downstream side of the long hopper cylinder 2, an adjustment unit 5 having a function of adjusting moisture, particle size, temperature, and the like is provided, and on the downstream side, an upstream seal for treating the biomass material with pressurized hot water A pressurized hot water treatment unit 7 sandwiched between the unit 6 and the downstream seal unit 9 is provided.

  In the present invention, the pressurized hot water treatment is not limited to water, but refers to a liquid component including water added with a chemical (for example, sulfuric acid or sodium hydroxide). Moreover, the screw extruder to be used may be either a single screw extruder or a twin screw extruder, but a twin screw extruder capable of applying stronger shear to the biomass material is preferable. In the vicinity of the downstream seal portion 9, there is a cooling portion 8 for cooling the cylinder 1, and there is an adjustment portion 10 for adjusting the particle diameter, temperature, moisture, etc. downstream thereof.

  A compactor 4 capable of press-fitting raw material with a screw (not shown) is installed directly above the long hopper cylinder 2 so that a bulky material can be stably fed into the screw extruder E. Furthermore, in order to supply the raw material at a constant rate, a weight type feeder 3 capable of adjusting the feed amount while measuring the weight is installed upstream thereof.

  A first liquid supply nozzle 11a and a first liquid supply pump 12a for supplying a liquid component such as water are installed on the downstream side of the upstream seal portion 6 to inject pressurized hot water. Further, in the vicinity of the cooling unit 8, a second liquid addition nozzle 11b for supplying a liquid component such as water to directly cool the biomass material, and a liquid component such as water to the second liquid addition nozzle 11b. The second liquid supply pump 12b for supplying the liquid is installed.

  Next, a continuous pressurized hot water treatment method for biomass material using this screw extruder will be described. As the lignin-containing biomass material to be introduced into the screw extruder, biomass materials such as wood and herbs are preferable. In addition, non-edible parts of grains can also be suitably used.

  The device that quantitatively supplies these biomass materials to the screw extruder is a screw-type constant-volume feeder that can feed the raw material quantitatively by rotating the screw at a constant rotational speed, and grasps the change in weight. There are various feeders such as a weight type feeder that discharges the raw material and feeds back the weight reduction amount to the raw material discharge speed to adjust the supply amount. Biomass materials are generally bulky and, in some cases, non-uniform in shape and size, a weight feeder that controls the discharge amount by weight is preferable as a device that quantitatively supplies it to a screw extruder. For materials that are particularly bulky or unstable in shape or particle size, it is preferable to use a disc-type or belt-type cutting device in combination with a weight-type feeder.

  The biomass material discharged from the weight type feeder 3 is fed into the screw extruder E. However, as described above, since the biomass material is generally bulky, when the biomass material is fed into a narrow space such as between the cylinder 1 and the screw, the weight type feeder is larger than the amount of material transported by the screw. This causes a feed neck phenomenon in which the amount of biomass material supplied from 3 is reduced, making it impossible to supply biomass material. Therefore, it is desirable to dispose the compactor 4 between the heavy-weight feeder 3 and the screw extruder E that can increase the bulk density of the material by forcibly pressing the raw material into the extruder using a screw or a piston. Further, it is preferable to install a long hopper cylinder 2 having a wide opening as the supply side cylinder.

  The biomass material supplied to the screw extruder E is carried to the adjusting unit 5 in the cylinder 1 by the propulsion effect of the screw. The adjustment unit 5 adjusts the amount of liquid components such as the temperature and moisture content of the biomass material, or applies shearing with a screw to make the shape and particle size of the raw material uniform, making it suitable for downstream processes. adjust. When the liquid component of the biomass material is large, a dehydrating cylinder is installed to discharge the liquid component out of the system. Conversely, when the liquid component is small, moisture is added using a liquid pump.

  An upstream seal portion 6 is disposed immediately downstream of the adjustment portion, and here, there is a screw that forms a seal by consolidating the biomass material so that water vapor generated in the pressurized hot water treatment portion 7 does not escape upstream. Has been placed. The screw shape is not particularly limited as long as the material is consolidated, and examples thereof include a seal ring and a reverse flight screw.

  A pressurized hot water treatment unit 7 is disposed in a portion sandwiched between the upstream seal unit 6 and the downstream seal unit 9. Here, the surface is renewed while retaining the biomass material and exposed to pressurized hot water for a certain period of time, thereby partially destroying the lignin tissue embedded in cellulose. A first liquid addition nozzle 11a connected to the first liquid pump 12a is installed at the uppermost stream of the pressurized hot water treatment unit 7, and a reaction such as water necessary for the destruction of the lignin structure is performed as necessary. Auxiliaries can be fed into the screw extruder E. The screw shape of the pressurized hot water treatment unit 7 is particularly suitable as long as the pressure can be made uniform by kneading and retaining a reaction aid such as water uniformly with the material, and further the surface can be renewed. There are no restrictions.

  The temperature of the pressurized hot water treatment unit 7 has a different optimum value depending on the biomass material used. However, when eucalyptus is used, it is preferably 200 ° C. or higher, but if it is too high, a substance that inhibits subsequent fermentation. Is not preferable. Moreover, it is desirable to maintain the pressure of the pressurized hot water treatment unit 7 higher than the saturated vapor pressure of water vapor at the temperature of the pressurized hot water treatment unit 7. If the pressure falls below the saturated vapor pressure of water vapor, all liquid components in the material will be vaporized, and material transport due to screw rotation will be difficult to control due to rapid volume expansion of the material, and the temperature will drop due to heat of vaporization. Thus, it is not preferable because the pressurized hot water treatment cannot be performed at a desired temperature. Therefore, the pressurized hot water treatment unit performs the pressurized hot water treatment at a pressure of 0.27 MPa (saturated vapor pressure of water at 130 ° C.) or higher and a temperature of the biomass material of 130 ° C. or higher.

  The downstream seal portion 9 is provided with a screw that forms a seal portion by consolidating the material so that water vapor generated in the pressurized hot water treatment portion 7 does not suddenly escape to the downstream side. The screw shape is not particularly limited as long as the material is consolidated as in the upstream seal portion 6, but a seal ring, a reverse flight screw, and the like can be given as examples.

  The cooling unit 8 arranged in the vicinity of the downstream seal unit 9 or in the vicinity including the downstream seal unit 9 cools the material and lowers the material temperature in the vicinity of the downstream seal unit 9 to maintain the pressurized hot water condition. A large amount of high-temperature water vapor generated at the sagging site is phase-transformed into a liquid, thereby imparting the property of significantly increasing the viscosity of the material. In addition, in order to provide a function of reducing the amount (volume) of water vapor that is about to leak downstream from the pressurized hot water treatment unit 7, for example, the cylinder is forcibly cooled with a cooling medium such as water or oil. The vicinity of the downstream seal portion 9 in the screw extruder is cooled by a cooling means, such as air cooling using a cooling fan. Moreover, biomass material is directly cooled by adding water to the biomass material in the downstream seal part 9 via the 2nd liquid addition nozzle 11b. The temperature of the biomass material to be cooled is included in the system in order to prevent the steam and biomass material from passing through the downstream seal portion 9 at a stretch and causing the temperature and pressure of the pressurized hot water treatment portion 7 to rapidly drop. It is preferable to cool to a temperature below the boiling point of a liquid component such as water. However, if the temperature is lowered too much, the material temperature of the biomass material in the pressurized hot water treatment unit 7 is lowered, and this is not preferable because separation between the substance containing cellulose and cellulose does not proceed. In addition, if too much liquid component such as water is added, a large amount of liquid component such as water is carried into the downstream process, which increases the capacity of the screw extruder and makes handling difficult during transportation. Therefore, it is not preferable.

  The biomass material that has been subjected to the pressurized hot water treatment is sent to the adjustment unit 10 disposed on the downstream side of the downstream seal unit 9 to make the liquid component such as the material temperature and water suitable for the subsequent steps. Adjusted. The adjusting unit 10 may be provided with a liquid nozzle according to the purpose, or may be provided with a vent port in order to remove liquid components such as water. Moreover, in order to assist the pressure holding force of a downstream seal part, you may arrange | position the screw which a material fills.

  A hardwood or softwood wood chip (particle size of 1 to 2 mm) with a water content of about 40% is introduced into a screw extruder through a heavy-weight feeder and compactor, and after adjusting the particle size and temperature in the adjustment unit, the pressure heat It processed in the water treatment part. The cylinder temperature of the pressurized hot water treatment unit was set to 200 to 220 ° C. As shown in Table 1, the temperature of the cooling part was set to a temperature lower than 100 ° C. which is the boiling point of water. The material temperature and pressure in the pressurized hot water treatment section were stable at the desired values. The material discharged from the tip of the screw extruder turned dark brown and gave off a sweet scent.

  As the screw extruder, a meshing twin screw extruder (trade name: TEX44αII manufactured by Nippon Steel Works) with L / D = 52.5 and a screw diameter of 47 mm was used.

(Comparative example)
A hardwood or softwood wood chip (particle size of 1 to 2 mm) having a water content of about 40% is introduced into a screw extruder through a weight feeder and a compactor, and after adjusting the particle size and temperature in the adjustment unit, pressurized hot water Processing was performed in the processing unit. As shown in Table 1, the cylinder temperature of the pressurized hot water treatment unit was set to 100 to 220 ° C. The temperature of the cooling part was set to a temperature of 100 ° C. or higher, which is the boiling point of water or higher. As the temperature and pressure of the pressurized hot water treatment section rises, the material with water vapor is intermittently ejected from the tip of the screw extruder, and the pressure of the pressurized hot water treatment section is periodically cycled accordingly. The temperature of the pressurized hot water treatment part could not be kept at a desired temperature, or the time of the pressurized hot water treatment became non-uniform.

  Table 1 shows the results of Comparative Examples 1 to 4 and Examples 1 to 5.

E Screw Extruder 1 Cylinder 2 Long Hopper Cylinder 3 Heavy Weight Feeder 4 Compactor 5, 10 Adjusting Unit 6 Upstream Sealing Unit 7 Pressurized Hot Water Treatment Unit 8 Cooling Unit 9 Downstream Sealing Unit 11a, 11b Liquidated Nozzles 12a, 12b Liquid Supply Pump 14 Motor 15 Reducer

Claims (4)

In the continuous pressurized hot water treatment method in which a biomass material containing lignin is continuously subjected to pressurized hot water treatment at 100 ° C. or higher by a screw extruder having a pressurized hot water treatment unit.
The pressurized hot water treatment part is provided with an upstream seal part on the upstream side and a downstream seal part on the downstream side,
A liquid addition nozzle for supplying a liquid component for cooling the biomass material is disposed in an upstream part of the downstream seal part,
By adding a liquid component to the biomass material from the liquid addition nozzle, and cooling the temperature of the biomass material in the downstream seal portion to below the boiling point of the liquid component contained in the system,
A continuous pressurized hot water treatment method for a biomass material, wherein a liquid component contained in the biomass material in the downstream seal portion is present in a liquid state to increase the pressure holding capacity of the downstream seal portion.   The pressurized hot water treatment unit performs pressurized hot water treatment at a pressure of 0.27 MPa (saturated vapor pressure of water at 130 ° C) or higher and a temperature of the biomass material of 130 ° C or higher. The continuous pressurized hot water treatment method of the biomass material described in 1. The biomass material according to claim 1 or 2, wherein the biomass material in the downstream seal portion is cooled by adding water in a liquid state to the biomass material in the upstream portion of the downstream seal portion. Continuous pressurized hot water treatment method. The biomass material in the downstream seal portion, by cooling by cooling means in the vicinity of the downstream sealing portion of the screw extruder, according to any one of claims 1 to 3, characterized in that cooling A continuous pressurized hot water treatment method for biomass materials.

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