JP5520495B2 - Method and apparatus for producing ethanol from food waste - Google Patents

Description

  The present invention relates to a method and apparatus for producing ethanol from food waste discharged from kitchens such as restaurants and schools. More particularly, the present invention relates to a method and apparatus for producing ethanol by saccharifying, fermenting and distilling food waste discharged from kitchens such as restaurants and schools.

  In recent years, many so-called biofuels have been produced using wheat, corn, or the like as a raw material. This biofuel is preferable from the viewpoint of global environmental protection because it suppresses the use of finite fossil fuels such as oil and coal and makes a breakthrough from a fossil fuel dependent society.

  However, such wheat and corn are foods for humans and livestock, which poses a major problem that food supply is stagnant. From this point of view and the necessity of effective utilization of food waste that has been questioned for many years, an ethanol production method using food waste has been devised so far.

  For example, saccharification of raw garbage produces saccharified liquid, and saccharification part that lowers the hydrogen ion concentration of saccharified liquid mainly by fermentation of lactic acid by microorganisms living in the raw garbage, and alcohol fermentation using saccharified liquid An alcohol production system having a fermentation section and a distillation section that separates crude alcohol and distilled waste liquid has been devised (see, for example, Patent Document 1).

  In addition, a liquefaction tank into which raw materials containing a large amount of carbohydrates and liquefaction enzyme are added, a saccharification tank into which liquefaction product and saccharification enzyme are added, a fermenter to ferment the saccharification product, and the fermentation product is separated into solid and liquid and distilled. A method for producing a flammable liquid using equipment comprising a distillation tank has been devised (see, for example, Patent Document 2).

  However, in the case of solid-liquid separation after saccharification, the sugar content in the saccharified solution is not recovered, and in the case of solid-liquid separation after fermentation, it is not included in the separated insoluble matter. There was a problem that the ethanol contained in the fermented broth was not recovered.

  Furthermore, since separate equipment is required for each process such as the saccharification process and fermentation process, the equipment cost is high, a large equipment installation area is required, and the maintenance cost is high to operate the equipment group. was there.

  Therefore, an object of the present invention is to recover the sugar content in the saccharified solution contained in the insoluble matter solid-liquid separated after saccharification, and to recover the ethanol in the fermentation solution contained in the insoluble matter solid-liquid separated after fermentation. Providing a method and an apparatus capable of increasing the amount of ethanol recovered from food waste, and equipment of equipment groups arranged in each of a saccharification process and a fermentation process, which are processes for producing ethanol To provide a method and an apparatus that can reduce the cost, reduce the installation area of the facility, and reduce the maintenance cost for operating the facility.

  In the present invention, “preliminary distillation” means concentrating an ethanol solution by heating and distilling a fermentation broth containing insoluble matter.

In order to solve the above-mentioned problems, the invention of the method for producing ethanol from food waste according to claim 1 is a method for producing ethanol from food waste containing carbohydrates, wherein the food waste and water are collected in a tank. The saccharification step in which the saccharification enzyme is introduced and saccharified after the temperature is adjusted by the temperature control means provided with the thermal refrigerant pipe 28 disposed in the lower part of the recovery tank 2 and the saccharification is performed. And a fermentation process in which the yeast after temperature adjustment by the temperature control means is introduced and fermented while opening and closing the on-off valve 55 for adjusting the pressure in the recovery tank 2, and after fermentation, by the temperature control means without solid-liquid separation The pre-distilling step for pre-distilling by adjusting the temperature and the discharging step for discharging the waste liquid containing insoluble matter after pre-distilling are performed in the same collection tank 2 .

The invention of an apparatus for producing ethanol from food waste according to claim 2 is an apparatus for producing ethanol from food waste containing carbohydrates, comprising a thermal refrigerant pipe 28 disposed in the lower part of the recovery tank 2. A temperature control means, a saccharification means for saccharification by adding a saccharification enzyme after carrying out stirring and temperature adjustment after putting food waste and water into the collection tank 2, and a yeast after stirring and temperature adjustment after saccharification Fermentation means for fermenting while opening and closing the on-off valve 55 for adjusting the pressure in the recovery tank 2, predistillation means for predistilling after fermentation without temperature separation without solid-liquid separation, and insoluble matter after predistillation The same collection tank 2 is provided with the discharge means which discharges the waste liquid containing this.

  The invention according to claim 1 is capable of recovering the sugar content in the saccharified liquid contained in the insoluble matter solid-liquid separated after saccharification, and ethanol in the fermented liquid contained in the insoluble matter solid-liquid separated after fermentation. The effect that can be recovered.

Since the saccharification process, fermentation process, pre-distillation process, etc. can be performed in the same collection tank 2, the equipment arranged in each process can be reduced, so the capital investment cost is reduced and the equipment installation area is reduced. In addition, there is an effect that the maintenance cost is lowered to operate the equipment.

  The invention according to claim 2 has the same effect as the invention according to claim 1.

It is the schematic of an ethanol collection | recovery apparatus. It is the schematic of the stirrer installed in the tank from the collection tank surrounding wall. After suction out the recovery tank is a schematic view of a pump or the like makes fed into the collection tank. It is AA sectional drawing of the snake tube shape part of the heat-medium cooling tube 28 in FIG.1, FIG.2 or FIG.3.

  Hereinafter, embodiments of the present invention will be described in detail.

An outline of an ethanol recovery apparatus for recovering ethanol from food waste will be described with reference to FIG. The ethanol recovery apparatus 1 has a substantially cylindrical recovery tank 2, an inlet 10 for supplying food waste, water, saccharifying enzyme, and yeast provided in the upper part of the recovery tank 2, and steam or cooling water. The hot refrigerant flow part 3 for adjusting the temperature of the solution 11 containing food waste, the stirring part 4 for stirring the solution 11 containing food waste, and the ethanol liquid 60 by cooling the pre-distilled steam. Cooling unit 5 to be used, waste liquid discharge unit 6 for discharging waste liquid containing insoluble matter after pre-distillation, and temperature sensor 14 for measuring the temperature of solution 11 containing food waste in the collection tank 2. , 15 and 16.

The inlet 10 at the top of the recovery tank 2 of the ethanol recovery apparatus 1 is opened and closed by a lid.

The thermal refrigerant flow section 3 includes a steam generator 21, an on-off valve 23 for opening and closing the steam flow path, a pump 22 with a cooling water tank for circulating cooling water, an on-off valve 24 for opening and closing the cooling water flow path, A water pipe 27, a thermal refrigerant pipe 28, a temperature sensor 29 for measuring the temperature of the steam or the cooling water, an on-off valve 25 for opening and closing the steam discharge path, and a steam release pipe 30 for releasing the steam into the atmosphere from the opening hole. The on-off valve 26 that opens and closes the cooling water return path, and the cooling water return pipe 31 that returns the cooling water that has passed through the recovery tank 2 to the pump 22 with the cooling water tank.

And the thermal refrigerant pipe | tube 28 is installed in the lower part of the collection tank 2, as shown in FIG. Further, the heat refrigerant pipe 28 can be circumscribed to the circumferential wall 20 of the recovery tank 2 and a spiral pipe (not shown) can be installed. Furthermore, the thermal refrigerant pipe 28 may also be allowed to circumscribing the corrugated tube at the bottom of the collecting tank 2 and the collecting tank 2 wall 20 is installed both spiral pipe.

In addition, the thermal refrigerant fluidizing section 3 is linked to a temperature sensor 14, 15 or 16 that measures the temperature of the solution 11 containing food waste, and is saccharified and fermented according to the temperature of the solution 11 containing food waste. In addition, it is also possible to perform control (not shown in the control unit) of raising and lowering the temperature to a temperature suitable for preliminary distillation.

Stirring unit 4 includes a drive motor 41, a rotary shaft 42 suspended from the cylindrical axis of the collecting tank 2 to be connected through a transmission mechanism within the collecting tank 2 to the drive motor 41, connected to the rotary shaft 42 rotates The rotary blade 43 rotates in the outer peripheral direction of the shaft 42.

As another type of the stirring portion 4, as shown in FIG. 2, the drive motor 44, a rotary shaft 45 which is provided inside the collection tank 2 from the bottom side wall of the collecting tank 2, the rotation shaft connected to the rotary shaft 45 It may be a type constituted by 45 rotating blades 46 rotating in the outer circumferential direction.

Further, as another type of the stirring portion 4, as shown in FIG. 3, the pump 47 and the solution circulation pipe 48 and the installed, food solution 11 containing the waste sucked from the lower portion of the collection tank 2 collecting tank 2 It may be of a type that circulates so as to be sent to the upper part.

In the upper part of the collection tank 2, a carbon dioxide gas generated by fermentation or a delivery port 17 for delivering steam generated when predistilling is provided. A steam pipe 52 is connected to the delivery port 17, and an open / close valve 55 that opens and closes a flow path for steam and the like, and a temperature sensor 54 that measures the temperature of steam and the like are installed in the steam pipe 52.

  The steam pipe 52 is connected to a steam liquefying pipe 53 provided in the cooling unit 5 through a joint 63. The vapor liquefying tube 53 is manufactured from a flexible tube or a non-flexible tube.

Although the opening and closing valve 55 a carbon dioxide gas staying in the space 7 in the fermentation step recovery vessel 2 is generated in order to discharge the opening, the adjustment of whether to open or close the opening and closing valve 55, the capacity of the collecting tank 2 When, for adjusting the opening and closing of the valve 55 and the amount of contained insoluble matters in the collecting tank 2 solution, the relationship between the capacitance of the space 7 in the collecting tank 2.

The bottom of the collection tank 2, the discharge port 18 is disposed for discharging the waste liquid containing the insoluble matter remaining in collection tank 2 after the preliminary distillation outlet tube 72 is connected to the discharge port 18, the discharge An opening / closing valve 73 is installed in the pipe 72, the other end of the discharge pipe 72 is open, and the waste liquid discharged from the other end is collected in the waste liquid collection tank 71.

And the vapor | steam containing the ethanol from the collection tank 2 by preliminary distillation is sent into the cooling part 5 shown in FIG. 1, and the ethanol liquid 60 is obtained. The cooling unit 5 includes a cooling water tank 50 filled with the cooling water 57, a steam liquefaction pipe 53 set in the cooling water tank 50, a cooling water inlet pipe 61 that is connected to the lower part of the cooling water tank 50 and feeds the cooling water, An on-off valve 56 that opens and closes the cooling water flow path, a cooling water delivery pipe 62 that is connected to the upper part of the cooling water tank 50 and delivers cooling water, a temperature sensor 58 or 59 that measures the temperature of the cooling water 57, and the cooling water tank 50 It comprises an ethanol liquid recovery tank 51 that recovers an ethanol liquid that has been liquefied by passing through the inside.

  Then, the cooling unit 5 controls to open and close the on-off valve 56 according to the difference between the temperature of the cooling water 57 detected by the temperature sensors 58 and 59 and the high-temperature limit setting temperature of the cooling water 57 or the on-off valve 56 closing set temperature ( (Not shown in the control section).

  Next, an outline of a method for producing ethanol from food waste will be described.

The food waste containing carbohydrate and dried to reduce the moisture content and water are introduced from the inlet 10 at the top of the collection tank 2 and the inlet 10 is closed.

  The input amount of food waste relative to the weight of water is set according to the moisture content of the food waste, and the input amount of saccharifying enzyme is set according to the total weight of the food waste and water.

  Moreover, the saccharification temperature and saccharification time for promoting saccharification are set according to the input amount of food waste, water and saccharifying enzyme, and the type of saccharifying enzyme.

  After reaching the set saccharification temperature, the inlet 10 is opened, saccharification enzyme is introduced, and the inlet 10 is closed. And in order to accelerate | stimulate saccharification of the solution 11 containing a food waste, while stirring the solution 11 containing an insoluble matter by the stirring part 4, the solution 11 containing the food waste among the temperature sensors 14, 15 or 16 is included. A steam generator that controls the flow of the heat medium when the temperature should be raised due to the difference between the set saccharification temperature and the temperature sensor detection temperature so that the temperature of the temperature sensor in contact with the temperature can be maintained at a preset saccharification temperature. 21 is operated, the on-off valve 23 and the on-off valve 25 are opened, and when the temperature is to be lowered, the on-off valve 24 and the on-off valve 26 are opened by operating a pump with a cooling water tank that controls refrigerant flow.

  Cool to fermentation temperature after saccharification. After reaching the fermentation temperature, the inlet 10 is opened, yeast is introduced, and the inlet 10 is closed. And in order to accelerate | stimulate fermentation of the saccharified liquid 12 containing the insoluble matter, fermentation time is set according to the quantity of the saccharified liquid 12, and the kind and input amount of yeast.

  In order to promote fermentation, the saccharified solution 12 containing the insoluble matter is stirred by the stirring unit 4, and the temperature sensor 14, 15, or 16 that is in contact with the saccharified solution 12 among the temperature sensors 14, 15 is set in advance. If the temperature should be raised due to the difference between the set fermentation temperature and the temperature sensor detection temperature, the steam generator 21 that controls the flow of the heat medium is activated and the on-off valve 23 and the on-off valve 25 are opened so that the temperature can be maintained. If the temperature should be lowered, the cooling water tank pump 22 for controlling the refrigerant flow is operated, and the on-off valve 24 and the on-off valve 26 are opened.

During the fermentation, in order to avoid the pressure increase in the collecting tank 2, such as by carbon dioxide gas generated by fermentation, and capacity recovery tank 2, and the amount of solution containing insoluble matters in the collecting tank 2, space inside the collecting tank 2 7 to adjust the opening / closing of the on-off valve 55.

Steam generation that controls the flow of the heat medium so that the temperature of the temperature sensor 14, 15 or 16 that is in contact with the fermentation broth 13 can be maintained at a preset predistillation temperature in order to promote predistillation. The device 21 is operated and the on-off valve 23 and the on-off valve 25 are opened. Moreover, at the time of preliminary distillation, the on-off valve 55 provided in the upper part of the collection tank 2 is opened to flow the pre-distilled steam.

After preliminary distillation, the waste liquid containing the insoluble matter remaining in the lower part in the recovery tank 2 is discharged from the discharge port 18 by opening the on-off valve 73 and recovered in the waste liquid recovery tank 71.

  Further, the pre-distilled vapor is liquefied in the process of flowing in the vapor liquefaction pipe 53 set in the cooling water tank 50, and the liquefied ethanol liquid 60 is poured out from the terminal portion of the vapor liquefaction pipe 53 to be an ethanol liquid recovery tank. 51 is collected.

  Since the temperature of the cooling water 57 rises due to the predistilled steam flowing in the vapor liquefaction pipe 53, the temperature sensor 58 is used so that the predistilled vapor liquefies in the process of flowing in the vapor liquefaction pipe 53. Alternatively, when the temperature of the cooling water 57 detected by 59 reaches a preset cooling water 57 high temperature limit temperature, the on-off valve 56 is opened and cooling water is fed from the cooling water feed pipe 61 to cool the cooling water 57. Then, the control is performed to close the on-off valve 56 when the preset on-off valve 56 closing temperature is reached.

  Next, although an Example is given and this invention is demonstrated, this invention is not limited by an Example.

The food waste containing carbohydrate and dried at a drying temperature of 80 ° C. to 100 ° C. to reduce the moisture content and the water are fed from the inlet 10 at the top of the collection tank 2.

  As for the food waste, 10 kg corresponding to about 25% by weight is added to 40 kg of water.

  Steam is generated while appropriately rotating the stirring unit 4 until the saccharification temperature of the temperature sensor 14, 15 or 16 that is in contact with the solution 11 containing food waste reaches 55 ° C. to 60 ° C. The steam from the vessel 21 is opened by opening the on-off valve 23 and the on-off valve 25 to cause the steam to flow in the thermal refrigerant pipe 28, and after reaching the set saccharification temperature, the saccharifying enzyme is introduced and the inlet 10 is closed.

  The saccharifying enzyme is added in an amount of 0.005% to 0.2% by weight based on the total amount of food waste and water.

  And the flow of a heat medium or a refrigerant | coolant is controlled, rotating the stirring part 4 suitably so that setting saccharification temperature may be maintained for about 24 hours.

  After the saccharification, the stirring unit 4 is kept until the fermentation temperature of the temperature sensor in contact with the saccharified liquid 12 containing the insoluble matter among the temperature sensors 14, 15 or 16 reaches a temperature range of 30 ° C to 35 ° C. While appropriately rotating, the pump 22 with a cooling water tank that controls the flow of the refrigerant is operated, the on-off valve 24 and the on-off valve 26 are opened, the cooling water flows in the thermal refrigerant pipe 28, and the temperature is lowered to cool to the set fermentation temperature. To do.

  After reaching the set fermentation temperature, the inlet 10 is opened, and yeast is added at 0.05 wt% to 0.5 wt% with respect to the total weight of the food waste and water, and the inlet 10 is closed. And the flow of a heat medium or a refrigerant | coolant is controlled, rotating the stirring part 4 suitably so that preset fermentation temperature may be maintained for 48 hours.

  In order to pre-distill after fermentation, the temperature of the temperature sensor 54 installed in the steam pipe 52 is raised until the temperature of the detected steam reaches 78 ° C. to 98 ° C., and the flow of the heat medium so as to maintain the detected steam temperature. Is controlled, and pre-distillation is performed. Finally, pre-distillation is terminated when the ethanol concentration generated from the vapor liquefaction tube 53 becomes 0.5% or less.

  The vapor generated by the preliminary distillation is liquefied by flowing in the cooling unit 5, becomes an ethanol liquid 60, and is recovered in the ethanol liquid recovery tank 51.

  The recovery rate of ethanol obtained by the main distillation in the distillation column after the preliminary distillation according to the above example is that 2.0 liters of ethanol having an ethanol concentration of 90% or more can be recovered from 10 kg of food waste, and after the conventional fermentation Ethanol recovery rate compared to 1.8 liter recovery of ethanol with 90% or higher ethanol concentration when solid-liquid separation is performed with a solid-liquid separator (trade name Slit Saver, Model SS-28, manufactured by Kendensha Co., Ltd.) Was improved by about 10%.

DESCRIPTION OF SYMBOLS 1 Ethanol recovery device 2 Recovery tank 3 Thermal refrigerant flow part 4 Stirring part 5 Cooling part 6 Waste liquid discharge part 7 Space 10 Input port 11 Solution containing food waste 12 Saccharified liquid containing insoluble substance 13 Insoluble substance included Fermentation liquid 14 Temperature sensor 15 Temperature sensor 16 Temperature sensor 17 Outlet 18 Discharge port 20 Recovery tank peripheral wall 21 Steam generator 22 Pump with cooling water tank 23 Open / close valve 24 Open / close valve 25 Open / close valve 26 Open / close valve 27 Cooling water pipe 28 Thermal refrigerant Pipe 29 Temperature sensor 30 Steam release pipe
DESCRIPTION OF SYMBOLS 31 Cooling water return pipe 41 Drive motor 42 Rotating shaft 43 Stirring blade 44 Drive motor 45 Rotating shaft 46 Stirring blade 47 Pump 48 Solution circulation pipe 50 Cooling water tank 51 Ethanol liquid recovery tank 52 Steam pipe 53 Steam liquefaction pipe 54 Temperature sensor 55 On-off valve 56 On-off valve 57 Cooling water 58 Temperature sensor 59 Temperature sensor 60 Ethanol liquid 61 Cooling water inlet pipe 62 Cooling water delivery pipe 63 Fitting 71 Waste liquid recovery tank 72 Drain pipe 73 On-off valve

JP 2006-325577 A JP 2006-325518 A

Claims (2)

A method for producing ethanol from food waste containing carbohydrates, the temperature by means of temperature control comprising a heat refrigerant pipe disposed in the lower part of the agitation and recovery tank after charging the food waste and water into the recovery tank A saccharification step in which saccharification enzyme is introduced after adjustment is performed, and after saccharification, the yeast after temperature adjustment by stirring and the temperature control means is introduced, and an on-off valve for adjusting the pressure in the collection tank is opened and closed The same recovery is performed for the fermentation process for fermentation, the pre-distillation process for pre-distillation after fermentation by adjusting the temperature by the temperature control means without separating the solid and liquid, and the discharge process for discharging waste liquid containing insoluble matter after pre-distillation. A method for producing ethanol from food waste, which is performed in a tank . An apparatus for producing ethanol from food waste containing carbohydrates, temperature control means comprising a thermal refrigerant pipe disposed in the lower part of the recovery tank, and stirring and after the food waste and water are put into the recovery tank A saccharification means for saccharifying by introducing a saccharification enzyme after temperature adjustment, and a fermentation means for fermenting by adding yeast after stirring and temperature adjustment after saccharification and opening and closing an on-off valve for adjusting the pressure in the collection tank And a predistilling means for predistilling after fermentation without temperature-adjusted solid-liquid separation and a discharging means for discharging waste liquid containing insoluble matter after predistillation are provided in the same recovery tank. Equipment for ethanol production from food waste.

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