JPH11169188A - Production of ethanol - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an industrial grade ethanol by utilizing a bio-mass resource such as an algae and a wood and fermenting the same. SOLUTION: This method for producing ethanol comprising a saccharization process 10 for hydrolyzing, smothering, etc., a bio-mass resource such as an algae or a wood by supplying a heat energy to form a saccharized raw material, a fermentation process 11 for producing ethanol by fermenting the saccharized raw material after the saccharization process 10, an ethanol separation process 12 for separating the ethanol with a distillation by supplying a heat energy to a fermented liquid obtained from the fermentation process 11 and containing ethanol, a waste water treatment process 13 for drying to solidify an impurity from which ethanol was separated by supplying a heat energy, is provided by using an industrial waste heat as a heat source for supplying a heat energy in the saccharization process 10, an ethanol separation process 12 and the waste water treatment process 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for producing industrial ethanol by fermentation using biomass resources such as algae and wood. In particular, the present invention relates to industrial waste such as a power plant as a heat source for producing ethanol. The present invention relates to an ethanol production method in which energy is saved by reusing heat, and resource saving is realized by reusing coal ash and the like in a fermentation process.

[0002]

2. Description of the Related Art In recent years, there have been problems in the long term, such as measures against the post-oil era and clean energy measures to protect the environment, as well as immediate energy measures such as a sharp rise in oil prices and supply insecurity. Now being asked, it is desirable to base on renewable resources.

[0003] In recent years, a system for producing ethanol by fermentation using biomass resources using plant resources as a raw material has been developed. According to this production method, biomass is a renewable resource, and since a liquid fuel is produced by fermenting ethanol from biomass as a raw material, the amount of carbon dioxide in the atmosphere does not increase, and other environmental pollution also occurs. Low and effective clean energy.

[0004] In general, biomass is an organic matter of a plant made from inorganic matter by photosynthesis, an animal eating it,
Microorganisms that decompose them, so-called producers, consumers, decomposers and all organic matter derived from them in so-called ecological terms. Specifically, as the biomass resource, sugar is produced from sugarcane, corn starch, and the like, and ethanol is produced by fermentation using microorganisms such as mold and yeast.

[0005] In this way, about 200,000 tons of industrial ethanol produced by fermentation is produced annually in Japan.

FIG. 5 is a diagram showing a typical production process of an ethanol production method.

[0007] As shown in FIG. 5, the whole process is large and comprises a saccharification step 1 for producing a saccharide raw material, a fermentation step 2 for fermenting the saccharide raw material with a microorganism such as yeast, and ethanol obtained by the fermentation treatment. And a wastewater treatment step 4 for treating impurities from which ethanol has been separated.

[0008] In the saccharification step 1, the processing operation differs depending on the raw material. For example, if the raw material is sugar, sterilization may be performed. If the raw material is starch, steaming is performed to decompose the starch into sugar. It is a carbohydrate raw material. In addition, when the raw material is cellulose, hydrolysis and steaming are performed to decompose the cellulose into sugar to obtain a saccharide raw material.

In the fermentation step 2, in order to perform a continuous reaction with high efficiency, the fermenter is filled with a porous carrier such as activated carbon or zeolite or a polymer such as calcium alginate gel to fix yeasts and fermentable bacteria. Perform the conversion. The raw material obtained in the saccharification step 1 is put into the fermentation tank, and fermentation is performed by a microorganism such as yeast in the fermentation tank.

Next, in the ethanol separation step 3, the ethanol-containing fermented solution obtained after the fermentation treatment is subjected to distillation or membrane separation to separate ethanol.

[0011] Finally, in the wastewater treatment step 4, ethanol is separated and the sludge-like impurities filtered and dried are solidified.

In the above-described method for producing ethanol, fossil fuels such as petroleum and coal are burned to generate heat or steam, and thermal energy is supplied to the saccharification step 1, the ethanol separation step 3, and the wastewater treatment step 4. Each processing is performed.

[0013]

However, in the conventional method, the heat energy supplied by burning fossil fuel in the industrial ethanol production process is several tens% of the heat energy of the produced ethanol. In order to achieve this, fossil fuel is used as thermal energy, so the value of biomass itself as clean energy is weakened, and the energy exchange efficiency is poor.

In fact, in the saccharification step 1 in the conventional ethanol production method, when starch or cellulose is used as a raw material, a large amount of heat energy is required to decompose them into a saccharide raw material. Separation process 3
Thus, a large amount of heat energy is required to separate ethanol by distillation. In wastewater treatment process 4,
A large amount of heat was required to dry the filtered solids, and all of this thermal energy was supplied by burning new fossil fuels.

In the prior art, porous materials such as zeolite and activated carbon, which are carriers of yeast and fermentable bacteria, and high-molecular materials are expensive, and the cost of recycling is high. Was not suitable for production.

More specifically, in the fermentation step 2 in the conventional ethanol production method, almost no heat energy is required, but if the reaction is continued continuously for a long time, yeasts and fermentable bacteria grow, and the pores of the carrier grow. And the area contributing to the reaction is reduced, and the reaction speed is reduced. For this reason, it is necessary to replace the carrier at regular intervals or continuously, but it is difficult to frequently replace the carrier because it is expensive. Therefore, these carriers are sometimes reused for treatment, but the reuse treatment requires a lot of time, steps, energy, etc., such as removal of attached microorganisms and revival of pores. Therefore, the cost of consuming and reusing the carrier is one of the factors that increase the cost of producing ethanol.

The present invention has been made to address the above-described problems, and effectively utilizes industrial waste heat from power plants, refuse incineration plants, steel mills, and the like as a heat source for producing ethanol. In addition to reusing energy to save energy, a large amount of coal ash and incinerated ash, one of the raw materials, is used as a carrier for fixing yeast and fermentable bacteria in the fermentation process. Provided is a method for producing ethanol, which realizes resource utilization.

[0018]

According to the first aspect of the present invention,
A saccharification process in which biomass resources such as algae and wood are hydrolyzed or steamed by supplying thermal energy to produce a saccharide material; a fermentation process in which the saccharide material is fermented after the saccharification process to produce ethanol; By supplying heat energy from the fermentation liquor containing ethanol obtained by the above to separate ethanol by distillation, and drying by supplying heat energy to the impurities from which ethanol was separated in the ethanol separation step. An ethanol production method having a wastewater treatment step for solidification, wherein industrial waste heat is used as a heat source for supplying thermal energy in the saccharification step, the ethanol separation step, and the wastewater treatment step.

According to the present invention, as a heat source for supplying thermal energy, in addition to a power plant, industrial waste, household waste, waste heat of a garbage incinerator, and waste heat of a steel mill can be used.

The invention according to claim 2 provides a saccharification step in which biomass resources such as algae and wood are hydrolyzed or steamed by supplying thermal energy to produce a saccharide raw material, and the saccharide raw material is fermented after the saccharification step. A fermentation process for producing ethanol, an ethanol separation process for separating ethanol by distillation by supplying thermal energy from a fermentation liquor containing ethanol obtained in the fermentation process, and an impurity from which ethanol was separated in the ethanol separation process. A wastewater treatment step of solidifying by supplying heat energy and drying, as a carrier for fixing yeast or fermentable bacteria in the fermentation step, using coal ash as one of the raw materials. It is characterized by using a porous body.

According to a third aspect of the present invention, in the method for producing ethanol according to the second aspect, a porous body produced from refuse incineration ash as a raw material is used as a carrier for fixing yeast or fermentable bacteria in the fermentation step. It is characterized by the following.

[0022]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
This will be described with reference to FIG.

First Embodiment (FIG. 1) FIG. 1 is a view showing a process for producing ethanol according to a first embodiment of the present invention.

As shown in FIG. 1, all steps of the ethanol production process include a saccharification step 10 for producing a saccharide material and a fermentation step 11 for fermenting the saccharide material with a microorganism such as yeast.
And an ethanol separation step 12 for separating ethanol from a fermentation solution containing ethanol obtained by the fermentation treatment.
And a wastewater treatment step 13 for treating impurities from which ethanol has been separated, and a power plant 14 for supplying thermal energy to each of these steps.

In the saccharification step 10, cellulose is used as a raw material. Then, steam is generated from the waste heat of the power plant 14 to perform hydrolysis and steaming, and is decomposed from cellulose to sugar to be a saccharide raw material.

In the fermentation step 11, a porous pellet containing coal described in the following second embodiment is placed in a fermenter to immobilize yeast in order to perform a highly efficient continuous reaction. Into this fermenter, the saccharide raw material obtained in the saccharification step 1 is charged to perform fermentation.

Next, in the ethanol separation step 12, the fermentation liquor containing ethanol obtained after the fermentation treatment is used
The heat is generated from the waste heat of No. 4 to carry out distillation, membrane separation treatment and the like, thereby separating ethanol.

Finally, in the wastewater treatment step 13, the sludge-like impurities from which ethanol has been separated and filtered are generated from the waste heat of the power plant 14 and dried to solids.

According to the present embodiment, 100
It is possible to extract waste heat of not less than ° C., which is sufficient for steam generation and drying, and the amount of heat is enormous, 1.5 times the generated power. From this, according to a trial calculation, if the entire waste heat of the power plant is used for the production of ethanol, it is possible to produce ethanol having a calorific value about twice that of the fuel consumed in the power plant.
Further, when the power is excessive at night, more steam can be used, which is useful for power load leveling.

Therefore, according to the present embodiment, most of the heat energy required for ethanol production can be supplied by the waste heat of the power plant, and significant energy savings and cost reductions can be realized.

Second Embodiment (FIG. 2) In this embodiment, a porous pellet containing coal which is a carrier for fixing yeast and fermentable bacteria in the fermentation step 11 of the ethanol production process of the first embodiment will be described. I do.

FIG. 2 is a diagram showing a fermentation step in the present invention.

As shown in FIG. 2, in the fermentation step, a coal ash pellet 16 which is a porous pellet containing coal ash is filled in a fermenter 15 in order to perform a highly efficient continuous reaction.
The yeast is immobilized. The fermenter 15 has a raw material inlet 17 into which a saccharide raw material flows into the side, an ethanol outlet 18 through which ethanol obtained by fermentation flows out, and a fermenter 1.
Carbon dioxide (CO ₂ ) outlet 19 provided at the top of
Are provided.

In the fermentation step 11 of this embodiment, a saccharide raw material is introduced into the fermenter 15 through a raw material inlet 17, and the saccharide raw material is introduced into the yeast immobilized by the coal ash pellets 16 in the fermenter 15. Pour and ferment. The ethanol obtained by fermentation is discharged from the ethanol outlet 18 and introduced into the next step, an ethanol separation step (not shown).

Also, coal ash pellets 1 for immobilizing yeast
6 is manufactured, for example, as follows.

Coal ash is a powder mainly composed of silica and alumina. The coal ash is used as one of the raw materials, and a hardening agent such as lime or gypsum is used as another raw material. And mix. Then, after adding water, kneading with a kneading machine and extruding to form a pellet with a molding machine,
Pelletize. This is cured with steam or hot water to form hard pellets 19. Since the pellets 19 are alkaline, the pH is adjusted to 4 to 6 with diluted phosphoric acid.

According to the present embodiment, calcium and phosphoric acid contained in the coal ash bind to each other to form apatite, which facilitates the attachment of proteins. Therefore, the coal ash pellet 19 is made of yeast or the like similarly to zeolite. Of microorganisms can be attached. The coal ash pellets 19 that have become unusable due to growth of yeasts and fermentable bacteria and pores are blocked can be discarded or reused after detoxification treatment such as heat treatment. Since the detoxification treatment can be rendered harmless by performing incineration, the treatment cost can be remarkably reduced as compared with the reuse treatment that requires the restoration of pores.

Further, according to the present embodiment, since coal ash which has been conventionally discarded in a large amount is used, there is no resource limitation even when a large amount of a carrier carrying yeast used in the fermentation step 11 is produced. It is possible to significantly reduce costs and extend the life of coal ash landfill sites.

Other Embodiments (FIGS. 3 and 4) FIG. 3 is a view showing a process for producing ethanol according to another embodiment of the present invention.

As shown in FIG. 3, the power plant 14 in FIG. 1 of the first embodiment is replaced with a refuse incineration plant 20. Others are the same as the first embodiment.

FIG. 4 is a view showing a fermentation process according to another embodiment of the present invention.

As shown in FIG. 4, the coal ash pellets 19 in FIG. 2 of the second embodiment are replaced with incinerated ash pellets 21. Others are the same as the second embodiment.

The refuse incineration plant 20 in this embodiment has a combustion temperature lower than that of a thermal power plant in order to prevent corrosion. Therefore, when used for power generation, the efficiency is reduced. For this reason, the ethanol production method of the present embodiment, in which heat generation can be effectively used, is more cost-effective than providing a power generation facility in the incineration plant 20.

Further, according to the present embodiment, incinerated ash discarded in a large amount can be used as a carrier for immobilizing yeast and fermentable bacteria. However, incineration ash is not homogeneous like coal ash and contains a large amount of harmful components such as heavy metals, so it has the drawback that the carrier production cost is higher than coal ash, but it has the same effect as coal ash be able to.

In this embodiment, the waste heat from the refuse incineration plant 20 is used as a heat source for supplying thermal energy, and the incineration ash pellets 21 are used as a carrier for immobilizing yeast and fermentable bacteria. Instead of the waste heat and incineration ash pellets 21 of the incineration plant 20, waste heat and fly ash pellets of a steel mill may be applied.

[0046]

As described above, according to the method for producing ethanol according to the present invention, energy can be reused to save energy, the cost for producing ethanol can be significantly reduced, and yeast and yeast can be used in mass production. There is no resource limitation of carriers for fermentable bacteria, and it can contribute to extending the life of land used for coal ash and incineration ash.

[Brief description of the drawings]

FIG. 1 is a diagram showing an ethanol production process according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a fermenter according to a second embodiment of the present invention.

FIG. 3 is a view showing an ethanol production process according to another embodiment of the present invention.

FIG. 4 is a diagram showing a fermenter according to another embodiment of the present invention.

FIG. 5 is a diagram showing a typical ethanol production process in the related art.

[Explanation of symbols]

 Reference Signs List 10 saccharification process 11 fermentation process 12 ethanol separation process 13 wastewater treatment process 14 power plant

Claims (3)

[Claims] 1. A saccharification process in which biomass resources such as algae and wood are hydrolyzed or steamed by supplying thermal energy to produce a saccharide material, and a fermentation process in which the saccharide material is fermented after the saccharification process to produce ethanol. And an ethanol separation step in which ethanol is separated by distillation by supplying thermal energy from a fermentation liquor containing ethanol obtained in this fermentation step, and thermal energy is supplied to impurities in which ethanol has been separated in the ethanol separation step. A wastewater treatment step of solidifying by drying and drying, wherein the industrial waste heat is used as a heat source for supplying thermal energy in the saccharification step, the ethanol separation step and the wastewater treatment step. Production method. 2. A saccharification process in which biomass resources such as algae and wood are hydrolyzed or steamed by supplying thermal energy to produce a saccharide material, and a fermentation process in which the saccharide material is fermented to produce ethanol after the saccharification process. And an ethanol separation step in which ethanol is separated by distillation by supplying thermal energy from a fermentation liquor containing ethanol obtained in this fermentation step, and thermal energy is supplied to impurities in which ethanol has been separated in the ethanol separation step. In a method for producing ethanol having a wastewater treatment step of solidifying by drying and drying, as a carrier for fixing yeast or fermentable bacteria in the fermentation step, a porous body produced using coal ash as one of the raw materials is used. A method for producing ethanol, characterized in that: 3. The method for producing ethanol according to claim 2, wherein a porous body produced from refuse incineration ash as one of raw materials is used as a carrier for fixing yeast or fermentable bacteria in the fermentation step. Production method.