JP2008246309A - Decomposition apparatus of organic matter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decomposition apparatus of organic matter capable of certainly recovering a low-molecular weight alcohol. <P>SOLUTION: The decomposition apparatus of organic matter 1 has a decomposition treatment tank 2 for setting the low-molecular weight alcohol to a supercritical state to perform the decomposition treatment of the organic matter and an exhaust passage 3 for exhausting the gas in the decomposition tank 2 from the decomposition tank 2 after the decomposition of the organic matter and is equipped with the first recovery part 4A arranged in the exhaust passage 3 to recover water from the gas and a second recovery part 4B arranged on the downstream side of the first recovery part 4A in the exhaust passage 3 to recover the low-molecular weight alcohol from the gas. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a decomposition treatment apparatus that decomposes an organic substance by bringing a low molecular weight alcohol such as methanol into a supercritical state.

  In recent years, a large amount of biomass waste has been discarded. A technique using a supercritical fluid has attracted attention as a technique for decomposing these wastes and collecting valuables. In particular, supercritical water has attracted attention as a supercritical fluid for a long time. When supercritical water is used, organic matter such as biomass waste is efficiently decomposed, but it is decomposed into low molecular weight compounds such as carbon dioxide and water as degradable organisms, so valuable materials must be recovered. Is difficult.

In view of this, a method for decomposing an organic substance by replacing a supercritical water with a low molecular weight alcohol in a supercritical state has already been proposed (see Patent Documents 1 and 2 below).
That is, the low molecular weight alcohol in a supercritical state has the ability to decompose and reduce the volume of organic matter under extremely mild conditions compared to supercritical water. In addition, a valuable glucose derivative can be efficiently obtained from polysaccharide substances such as starch and cellulose in the organic matter.

  Furthermore, according to the technique using a mixed solvent of a low molecular weight alcohol and a little water, it is possible to realize a reaction with a supercritical low molecular weight alcohol and a subcritical water. Since subcritical water exhibits milder reactivity than supercritical water, organic substances can be kept at a reactivity that does not decompose into low molecular compounds such as carbon dioxide and water. In the degradation of the polysaccharide substance, since it plays a role of assisting the degradation reaction of cellulose that is difficult to decompose only with low molecular weight alcohol, the glucose derivative that is a valuable material can be recovered more efficiently.

JP 2001-170601 A JP-A-2005-296906

  By the way, in the decomposition treatment of organic matter using the above-mentioned mixed solvent of low molecular weight alcohol and water, organic matter such as biomass waste which is the object to be treated, and mixing of excess alcohol and water with respect to this organic matter. After putting the solvent in the decomposition treatment tank, the decomposition treatment is performed by heating and pressurizing to bring the mixed solvent into a supercritical state. In this case, in the gas present in the decomposition treatment tank after the supercritical reaction, in addition to nitrogen and oxygen in the air, methanol and water remaining in the reaction process, and methanol and water generated in the decomposition reaction Is present. If such a gas in the decomposition treatment tank is released into the atmosphere as it is, the low molecular weight alcohol remaining without contributing to the reaction is diffused into the atmosphere in the form of gas, and expensive low molecular weight alcohol is consumed unnecessarily. Will be. Moreover, although methanol is preferably used as the low molecular weight alcohol, methanol is harmful to the human body and may cause pollution.

Therefore, the inventors of the present invention do not release the gas in the decomposition treatment tank into the atmosphere as it is, but cool it to a temperature lower than the boiling point of the low molecular weight alcohol in the middle of the exhaust passage to liquefy the low molecular weight alcohol. I wanted to recover and reuse it.
However, if the recovered low molecular weight alcohol contains a large amount of water, it is effective because a new low molecular weight alcohol must be added even if the recovered low molecular weight alcohol is used for the subsequent decomposition treatment. It cannot be said that it is an important reuse.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide an organic matter decomposition treatment apparatus that can reliably recover low molecular weight alcohol.

  In order to achieve the above object, an organic matter decomposition treatment apparatus according to the present invention is supplied with an organic matter and a low-concentration alcohol aqueous solution having a predetermined concentration, and decomposes the organic matter with the low-molecular weight alcohol in a supercritical state. And an exhaust passage for discharging the gas in the decomposition treatment tank from the decomposition treatment tank after the organic matter decomposition treatment, in the organic matter decomposition treatment apparatus, a first recovery unit that is disposed in the exhaust passage and collects water from the gas, And a second recovery unit that is disposed downstream of the first recovery unit in the exhaust passage and recovers low molecular weight alcohol from the gas.

  Further, in the above-described configuration, the first recovery unit is configured to recover water at a temperature equal to or higher than the boiling point of the low molecular weight alcohol at the exhaust passage pressure and less than the boiling point of water at the exhaust passage pressure. .

  In each of the configurations described above, the second recovery unit is configured to recover the low molecular weight alcohol at a temperature lower than the boiling point of the low molecular weight alcohol at the exhaust passage pressure.

  Further, in each configuration described above, the low molecular weight alcohol recovered by the second recovery unit is used as a raw material of the low molecular weight alcohol aqueous solution used in the decomposition treatment tank.

  According to the organic matter decomposition treatment apparatus of the present invention, water having a high boiling point is recovered by the first recovery unit. Therefore, since the water recovery load is reduced in the second recovery unit on the downstream side, low molecular weight alcohol having a low boiling point can be reliably recovered.

  In addition, in the case where the first recovery unit recovers water at a temperature not less than the boiling point of the low molecular weight alcohol at the exhaust passage pressure and less than the boiling point of the water at the exhaust passage pressure, It can be recovered.

  If the second recovery unit recovers the low molecular weight alcohol at a temperature lower than the boiling point of the low molecular weight alcohol in the exhaust passage pressure, the low molecular weight alcohol can be reliably recovered.

  Furthermore, in the case where the low molecular weight alcohol recovered in the second recovery unit is used as a raw material for the low molecular weight alcohol aqueous solution used in the decomposition treatment tank, the recovered low molecular weight alcohol can be reused without wasting it. .

The best mode for carrying out the present invention will be described with reference to the drawings. The embodiment described below is merely an example embodying the present invention, and does not limit the technical scope of the present invention. FIG. 1 is a configuration diagram including a partial cross section of an organic matter decomposition treatment apparatus according to an embodiment of the present invention.
In the figure, an organic matter decomposition treatment apparatus 1 according to this embodiment includes a decomposition treatment tank 2 for decomposition treatment of cellulosic waste (an example of an organic substance), an exhaust passage 3 for discharging gas in the decomposition treatment tank 2, and an exhaust. An alcohol recovery unit 4 that recovers methanol and water in the gas of the passage 3 is provided.

  The decomposition treatment tank 2 is formed as a heat-resistant and pressure-resistant sealed container that can withstand pressure (8.09 MPa or more) and temperature (239 ° C. or more) at which methanol becomes a supercritical state. A supply pipe 12 that receives cellulosic waste is connected to the upper surface of the decomposition treatment tank 2, and the supply pipe 12 is connected to an organic substance tank 14 via an electromagnetic on-off valve 13. A supply pipe 17 that receives an aqueous methanol solution is connected to the upper part of the decomposition treatment tank 2, and the supply pipe 17 is connected to an alcohol aqueous solution tank 19 through an electromagnetic on-off valve 25 and a pump 18. The bottom of the decomposition treatment tank 2 is connected to an extraction pipe 29 for discharging glucose derivatives, by-products and water generated by the decomposition treatment of the cellulosic waste from the decomposition treatment tank 2, and the extraction pipe 29 is connected to the electromagnetic on-off valve 30. To the subsequent distillation step 31.

  In the jacket covering the outer peripheral surface of the decomposition treatment tank 2, a heater 33 for heating the decomposition treatment tank 2 to a predetermined temperature and a cooler 34 for lowering the temperature in the tank are accommodated. The heater 33 is realized by, for example, an electric heater, and the cooler 34 is realized by a cooling oil circulation pipe or the like. The heating operation by the heater 33 and the cooling operation by the cooler 34 are controlled by the temperature control device 32. Further, the decomposition treatment tank 2 is provided with a temperature sensor 15 for detecting the temperature in the tank and a pressure sensor 16 for detecting the pressure in the tank. The alcohol aqueous solution tank 19 is connected to an alcohol tank 21 storing high-purity methanol via an electromagnetic opening / closing valve 20, and connected to a supply source of water 23 via an electromagnetic opening / closing valve 22. A concentration sensor 24 for detecting the methanol concentration is provided.

The end of the exhaust passage 3 is connected to the upper surface of the decomposition treatment tank 2. The exhaust passage 3 is provided with an exhaust amount adjusting valve 5 and a flow rate sensor 35. An alcohol recovery unit 4 is provided in the middle of the exhaust path 3. On the downstream side of the alcohol recovery unit 4 in the exhaust passage 3, a methanol removing device 53 containing activated carbon or the like is arranged, and at the tip of the exhaust passage 3, it is automatically applied with a minute positive pressure (for example, about 100 mmH ₂ O (water column)). An open air release valve 54 is provided. The flow sensor 35 is composed of, for example, an orifice meter.

The alcohol recovery unit 4 mainly includes a first recovery unit 4A provided on the upstream side and a second recovery unit 4B provided on the downstream side of the first recovery unit 4A.
The first recovery unit 4A includes, for example, a heat exchanger 60A in a sealed container in which a heat medium is accommodated therein, a cooler 36 including a chilled water pipe disposed in the heat exchanger 60A, and the heat exchanger 60A. And a heater 39 composed of a deployed steam pipe or the like. The cooler 36 is configured such that the flow rate of cold water from the chiller 37 </ b> A is adjusted by opening and closing a flow rate control valve 38 on the way. The heater 39 is configured such that the flow rate of the heating steam from the boiler 40 is adjusted by opening and closing the flow control valve 41 in the middle.
In the heat exchanger 60A, the exhaust passage 3 is a recovery portion conduit 44A for cooling the gas. A branch part 59A for taking out the condensate is formed in the recovery part pipe line 44A. A pressure sensor 45A for detecting the pressure in the pipe line and a temperature sensor 46A for detecting the temperature in the recovery part pipe line 44A are installed in the recovery part pipe line 44A. The first temperature adjusting means 57 is configured by a combination of the configuration including the heater 39, the flow rate control valve 41, and the boiler 40 and the configuration including the cooler 36, the flow rate control valve 38, and the chiller 37A.

Similarly, the second recovery unit 4B includes, for example, a heat exchanger 60B that is a sealed container in which, for example, a heat medium is accommodated, and a cooler 42 that includes a refrigerant pipe or the like disposed in the heat exchanger 60B. . In the cooler 42, the flow rate of the refrigerant from the chiller 37B is adjusted by opening and closing the flow control valve 43 in the middle.
In the heat exchanger 60B, the exhaust passage 3 serves as a recovery unit conduit 44B for cooling the gas. A branch part 59B for taking out the condensate is formed in the recovery part pipe line 44B. A pressure sensor 45B for detecting the pressure in the pipeline and a temperature sensor 46B for detecting the temperature in the pipeline are installed in the recovery unit pipeline 44B. The second temperature control means 58 is configured by the configuration including the cooler 42, the flow rate control valve 43, and the chiller 37B.

  In the above, in order to facilitate the illustration and explanation, the recovery portion pipes 44A and 44B of the exhaust passage 3 are described in a U-shape, and the branch portions 59A and 59B are formed at the lowermost portions. However, the structure and shape of the exhaust path in the alcohol recovery section of the present invention are not limited as long as water and low molecular weight alcohol can be condensed and extracted from the gas in the path.

  The branch portion 59 </ b> A of the heat exchanger 60 </ b> A described above is connected to the extraction pipe 8 via the electromagnetic opening / closing valve 47, and the extraction pipe 8 is connected to the water receiving tank 10. A discharge pipe 49 is connected to the water receiving tank 10, and the discharge pipe 49 is connected to the storage tank 52 via an electromagnetic on-off valve 50 and a pump 51. Further, the branch portion 59 </ b> B of the heat exchanger 60 </ b> B is connected to the extraction pipe 9 via the electromagnetic opening / closing valve 48, and the extraction pipe 9 is connected to the alcohol receiving tank 11. A recovery pipe 28 is connected to the alcohol receiving tank 11, and the recovery pipe 28 is connected to the alcohol aqueous solution tank 19 via an electromagnetic on-off valve 26 and a pump 27.

  As shown in the block diagram of FIG. 2, the control device 6 that controls the organic matter decomposition device 1 is constituted by, for example, a microcomputer having a general-purpose central processing unit CPU, a memory M, a data bus BD, and the like. On the input side of the microcomputer, an external input device 7 such as a keyboard and a mouse, temperature sensors 15, 46A and 46B, pressure sensors 16, 45A and 45B, a flow sensor 35, and a concentration sensor 24 are connected so that signals can be input. . On the output side of the microcomputer, there are an exhaust amount adjusting valve 5, flow rate control valves 38, 41, 43, electromagnetic on-off valves 13, 20, 22, 25, 26, 30, 47, 48, 50, 62, and pumps 18, 27. , 51 are connected to enable command output.

  Therefore, the operation of the organic matter decomposition treatment apparatus 1 configured as described above will be described. First, the electromagnetic on-off valve 20 is opened and a predetermined amount of high-purity methanol in the alcohol tank 21 is supplied to the alcohol aqueous solution tank 19, and the electromagnetic on-off valve 22 is opened to supply water 23 to the alcohol aqueous solution tank 19 in a predetermined amount. In this example, the mixing ratio of methanol and water is, for example, 4: 1, and is set so as to prepare an 80 vol% methanol aqueous solution. The concentration of the methanol aqueous solution in the alcohol aqueous solution tank 19 is detected by the concentration sensor 24, and the control device 6 controls the opening / closing of the electromagnetic open / close valves 20 and 22 so that the methanol aqueous solution is 80 vol%.

Then, the control device 6 opens the electromagnetic on-off valve 13 with the electromagnetic on-off valves 25, 30, 62 and the exhaust amount adjusting valve 5 closed, and supplies the cellulosic waste in the organic matter tank 14 into the decomposition treatment tank 2. To do. Next, the control device 6 starts the pump 18, opens the electromagnetic on-off valve 25, and supplies the methanol aqueous solution in the alcohol aqueous solution tank 19 into the decomposition treatment tank 2 from the supply pipe 17. In this example, the supply ratio of the cellulosic waste and the aqueous methanol solution is approximately 0.2 to 0.4: 1 (weight ratio).
Then, after closing the electromagnetic on-off valves 13 and 25, the control device 6 operates the heater 33 of the temperature adjustment device 32 to heat the inside of the decomposition treatment tank 2. Among them, after the temperature in the tank detected by the temperature sensor 15 becomes 239 ° C. or higher and the pressure detected by the pressure sensor 16 becomes 8.09 MPa or higher, the decomposition reaction for obtaining the glucose derivative from the cellulosic waste is completed. The above temperature / pressure conditions are maintained. During the decomposition reaction, the methanol aqueous solution and the cellulose waste in the decomposition treatment tank 2 may be gently stirred by a stirring means (not shown).

  When the above decomposition reaction is completed, the control device 6 operates the cooler 34 of the temperature control device 32 to gradually cool the inside of the decomposition treatment tank 2. However, the temperature in the tank may be lowered by natural cooling of the decomposition treatment tank 2 without operating the cooler 34. In parallel with this, the control device 6 operates the first temperature control means 57 and the second temperature control means 58 to maintain the recovery part pipeline 44A of the first recovery part 4A at 80 ° C., and the second recovery part. The 4B recovery section conduit 44B is maintained at 5 ° C. Among them, when the temperature in the tank is lowered to 120 ° C., for example, the electromagnetic on-off valve 62 of the exhaust passage 3 is opened. In this case, prior to opening of the electromagnetic on-off valve 62, the control device 6 opens the valve opening of the exhaust amount adjusting valve 5 slightly in advance. The minute opening degree is 99.5% (predetermined yield) of methanol in the gas in the exhaust passage 3 and the alcohol recovery unit 4 even when the high-temperature and high-pressure gas in the decomposition treatment tank 2 is exhausted from the exhaust passage 3. This is the opening that can be captured and recovered.

  Subsequently, the control device 6 opens the valve opening degree of the exhaust amount adjustment valve 5 as the tank temperature decreases. Thereby, the exhaust amount of the gas passing through the exhaust amount adjusting valve 5 is adjusted so as to increase. The exhaust amount of the gas flowing through the exhaust passage 3 is detected by the flow sensor 35 and transmitted to the control device 6. Therefore, the central processing unit CPU of the control device 6 sets the exhaust amount adjustment valve 5 so that the exhaust amount detected by the flow sensor 35 approaches the target exhaust amount corresponding to the temperature in the tank detected by the temperature sensor 15. Open / close control of valve opening.

In general, the boiling point of methanol under normal pressure (1 atm) is 64.7 ° C, but when the pressure of the environment in which it is placed becomes higher than normal pressure, the boiling point becomes higher than 64.7 ° C and lower than normal pressure. It is known that the boiling point is lower than 64.7 ° C.
And the gas which flowed in the collection | recovery part pipeline 44A of 4 A of 1st collection | recovery parts is cooled to 80 degreeC. At this time, the methanol in the gas remains as a gas, and most of the water vapor condenses to become water, and flows down to the branch portion 59A. In this case, since methanol and water are azeotropes, condensed water containing a very small amount of methanol accumulates in the branch portion 59A. The condensed water accumulated in the branching portion 59A is discharged from the extraction pipe 8 to the water receiving tank 10 when the electromagnetic opening / closing valve 47 is opened. That is, the first recovery unit 4A has a temperature (80 ° C.) that is not less than the boiling point (more than 65 ° C.) of methanol and less than the boiling point (more than 100 ° C.) of water at the pressure in the exhaust passage 3 (positive pressure slightly higher than atmospheric pressure). The water is recovered at ℃). In addition, when the inside of the heat exchanger 60A falls below 80 ° C. as the temperature of the decomposition treatment tank 2 falls, the heater 39 is operated to heat and hold at 80 ° C.

  The gas that has passed through the first recovery part 4A is cooled to 5 ° C. in the recovery part pipeline 44B of the second recovery part 4B. As a result, methanol vapor occupying most of the gas is condensed into liquid methanol, and a small amount of water vapor is also condensed and flows down to the lowermost branch portion 59B. Therefore, methanol containing an extremely small amount of water is reliably recovered in the branching portion 59B. The methanol accumulated in the branching portion 59B is discharged from the extraction pipe 9 to the alcohol receiving tank 11 by opening the electromagnetic opening / closing valve 48.

  99.5% or more of the amount of methanol in the gas is removed from the amount of methanol in the gas on the inlet side of the exhaust passage 3 at the time of leaving the second recovery unit 4B. In other words, the second recovery unit 4B is configured to recover methanol at a temperature at which the low-molecular-weight alcohol can be recovered at a predetermined yield (99.5%) or less at the pressure in the exhaust passage 3 or less. ing. Then, methanol that has not been captured by the exhaust passage 3 and the alcohol recovery unit 4 is adsorbed and removed by the activated carbon of the methanol removing device 53. In this way, the gas from which methanol has been removed is released from the atmospheric release valve 54 into the atmosphere.

On the other hand, the methanol delivered to the alcohol receiving tank 11 is sent from the recovery pipe 49 to the alcohol aqueous solution device 19 by opening the electromagnetic on-off valve 26 and starting the pump 27, and is reused as a part of the methanol supply source. Therefore, the recovered methanol can be reused without being wasted.
On the other hand, the water discharged to the water receiving tank 10 is sent from the discharge pipe 49 to the storage tank 52 by opening the electromagnetic opening / closing valve 47 and starting the pump 51. The water in the storage tank 52 can be used as a part of the water 23 supplied to the alcohol aqueous solution device 19 after performing a filtration process or the like.
Thus, in the decomposition treatment tank 2 in which the temperature in the tank is lowered to about 30 to 40 ° C., the electromagnetic on-off valve 30 is opened, and glucose derivatives, by-products, and water generated in the decomposition treatment tank 2 are extracted from the piping. 29 to the distillation step 31. In the distillation step 31, by-products and water are distilled off from the glucose derivative.

  As described above, the organic matter decomposition treatment apparatus 1 according to this embodiment collects water in the first collection unit 4A, so that the water collection load in the second collection unit 4B on the downstream side is reduced. As a result, methanol can be reliably recovered in the second recovery part 4B.

In the above embodiment, the organic substance inlet is provided on the upper surface of the decomposition treatment tank 2 and the methanol aqueous solution inlet is provided on the side surface of the decomposition treatment tank 2, but the present invention is not limited thereto. For example, the organic substance inlet may be provided on the side surface of the decomposition treatment tank 2, the methanol aqueous solution inlet may be provided on the upper surface of the decomposition treatment tank 2, or both the organic substance inlet and the methanol aqueous solution inlet may be provided on the side surface of the decomposition treatment tank 2. . Moreover, as an organic substance supply structure, instead of the electromagnetic on-off valve 13, a flanged supply port may be formed in the decomposition treatment tank, and this supply port may be bolted with a pressure-resistant lid and sealed.
In place of the atmospheric release valve 54, an electromagnetic open / close valve that opens at a higher operating pressure than the atmospheric release valve 54 can be used as the release valve. In this case, the electromagnetic open / close valve is detected by the pressure sensors 45A and 45B. Open and close based on

Moreover, as an organic substance used for this invention, biomass-type wastes, such as wood, paper, paper pulp, agricultural products, polysaccharides in a municipal waste, etc. containing said cellulose-type waste are mentioned.
The low molecular weight alcohol that can be used in the present invention is not particularly limited, and ethanol, propanol, and the like can be used. However, methanol is most preferable in that a glucose derivative can be selectively obtained in a high yield. The alcohol concentration of the low molecular weight alcohol aqueous solution used for the decomposition of the organic substance is preferably 75 to 95 vol% in order to suppress the excessive decomposition of the organic substance and selectively produce a glucose derivative.

It is a block diagram including the partial cross section of the organic substance decomposition processing apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows the control system of the said organic substance decomposition processing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Organic substance decomposition processing apparatus 2 Decomposition processing tank 3 Exhaust path 4A 1st collection | recovery part 4B 2nd collection | recovery part 9 Extraction pipe 10 Water receiving tank 11 Alcohol receiving tank 19 Alcohol aqueous solution tank 26 Electromagnetic on-off valve 27 Pump 28 Recovery piping 45A Pressure sensor 45B Pressure Sensor 46A Temperature sensor 46B Temperature sensor 57 First temperature adjustment means 58 Second temperature adjustment means

Claims (4)

An organic substance and a low-molecular-weight alcohol aqueous solution of a predetermined concentration are supplied, a decomposition treatment tank that decomposes the organic substance with the low-molecular weight alcohol in a supercritical state, and a gas in the decomposition treatment tank is discharged from the decomposition treatment tank after the organic substance decomposition treatment In an organic matter decomposition treatment apparatus having an exhaust path,
A first recovery unit that is disposed in the exhaust path and recovers water from the gas;
An organic matter decomposition treatment apparatus comprising: a second recovery unit that is disposed downstream of the first recovery unit in the exhaust path and recovers low molecular weight alcohol from the gas. The first recovery section is configured to recover water at a temperature not lower than the boiling point of the low molecular weight alcohol at the exhaust passage pressure and lower than the boiling point of the water at the exhaust passage pressure. The organic substance decomposition treatment apparatus as described. The organic substance decomposition treatment according to claim 1 or 2, wherein the second recovery unit is configured to recover the low molecular weight alcohol at a temperature lower than the boiling point of the low molecular weight alcohol in the exhaust passage pressure. apparatus. The organic substance according to any one of claims 1 to 4, wherein the low molecular weight alcohol recovered in the second recovery unit is used as a raw material of the low molecular weight alcohol aqueous solution used in the decomposition treatment tank. Decomposition processing equipment.

Images