CN101676394B - Method for preparing alcohol by utilizing potato materials - Google Patents

Abstract

A method for preparing alcohol by utilizing potato materials comprises the following steps: grinding the potato materials, mixing the products after grinding with enzyme and carrying out enzymolysis to obtain enzymolysis products; fermenting the enzymolysis products, separating alcohol from the fermentation products, and then carrying out solid-liquid separation on the liquid waste. The method is characterized by adding water-soluble alginate esters and/or water-soluble alginates into the liquid waste before carrying out solid-liquid separation on the liquid waste. Compared with the prior art, the method of the invention obviously shortens the solid-liquid separation time and increases the treatment capacity of the liquid waste in unit time under the condition of dispensing with new equipment.

Description

A method for preparing ethanol from potato raw materials

technical field

The invention relates to a method for preparing ethanol, more particularly to a method for preparing ethanol by using tuber raw materials.

Background technique

Potatoes, such as sweet potatoes, potatoes, cassava, etc., are rich in starch, so they are widely used in the fields of fermentation sugar and starch production.

Cassava is a tropical and subtropical perennial and temperate annual tuber shrub. It is native to South America and is suitable for growth in low latitude areas with an average temperature of 25-29°C and an average annual precipitation of 1000-1500 mm. About 1820 years ago, cassava spread to southern China and was mainly grown in Guangdong, Guangxi and Hainan, and now gradually expanded to Yunnan, Fujian, Guizhou and other provinces. There are two types of cassava: bitter cassava (poisonous cassava) and sweet cassava (non-toxic cassava). The main chemical composition of fresh cassava root is water, followed by carbohydrates, and some lesser amounts of protein, fat and pectin. The content of fresh cassava starch reaches 25-30% by weight, and the content of dry cassava starch is about 70% by weight.

Since the waste liquid produced by fermenting potato raw materials to ethanol contains high concentrations of organic matter, the waste liquid discharged from most ethanol plants by fermenting potato raw materials to produce ethanol is directly discharged outside without effective treatment, causing damage to the local and downstream water environment. Serious impact.

At present, the treatment methods for the waste liquid produced by fermentation of potato raw materials to produce ethanol include: 1. Incineration method, that is, the waste liquid produced by fermentation of potato raw materials to produce ethanol is concentrated and then incinerated. The disadvantage of this method is that it is easy to cause secondary pollution after incineration; 2. 1. Fermentation of waste liquid from potato raw materials to produce ethanol to produce biogas. The disadvantages of this method are large investment and high control technology requirements.

Therefore, at present, the solid residue in the waste liquid produced by cassava fermentation to produce ethanol is usually used as feed to process the waste liquid. The method includes separating the waste liquid from solid to liquid to obtain a solid product; and then drying the solid product. The method is a treatment method for the waste liquid produced by cassava fermentation to produce ethanol with low investment, easy operation and environmental friendliness. In this case, the processing capacity of solid-liquid separation becomes a key factor in determining the size of waste liquid processing capacity.

The problem with the current method for treating the waste liquid produced by cassava fermentation to ethanol is that the period of solid-liquid separation is too long, resulting in a small amount of waste liquid treatment, and the lower operating load of the device for producing ethanol by cassava fermentation. Unable to meet the requirements.

Contents of the invention

The purpose of the present invention is to overcome the shortcoming of too long period of solid-liquid separation in the existing method for preparing ethanol from potato raw materials, and provide a method for preparing ethanol from potato raw materials with a shorter period of solid-liquid separation.

The invention provides a method for preparing ethanol from potato raw materials. The method comprises pulverizing the potato raw materials, mixing the pulverized products with enzymes, and enzymatically hydrolyzing them to obtain enzymatic hydrolysis products; Separating ethanol from the waste liquid, and then carrying out solid-liquid separation on the waste liquid, wherein, adding water-soluble alginate and/or water-soluble alginate to the waste liquid before carrying out solid-liquid separation on the waste liquid.

In the present invention, by adding water-soluble alginate and/or water-soluble alginate to the waste liquid of cassava fermentation to prepare ethanol, the time of solid-liquid separation is significantly shortened, and the time for solid-liquid separation is significantly improved without adding new equipment. The processing capacity of the waste liquid per unit time is reduced, thereby solving the bottleneck of the lower operating load of the device for producing ethanol by cassava fermentation, and improving the production capacity of the device for producing ethanol by cassava fermentation.

Detailed ways

The invention provides a method for preparing ethanol from potato raw materials. The method comprises pulverizing the potato raw materials, mixing the pulverized products with enzymes, and enzymatically hydrolyzing them to obtain enzymatic hydrolysis products; Separating ethanol from the waste liquid, and then carrying out solid-liquid separation on the waste liquid, wherein, adding water-soluble alginate and/or water-soluble alginate to the waste liquid before carrying out solid-liquid separation on the waste liquid.

According to the present invention, the amount of water-soluble alginate and/or water-soluble alginate can be changed in a wide range, as long as the time of solid-liquid separation can be shortened, preferably, relative to 1000 parts by weight of waste Liquid, the consumption of water-soluble alginate and/or water-soluble alginate is 0.05-1 weight part; The consumption is 0.1-0.5 weight part.

The type of water-soluble alginate can be changed in a wide range, as long as the collision between molecules in the waste liquid can be intensified, and the small molecules that are not easy to precipitate can be combined into macromolecules to form larger flocs. Here, the relative molecular weight of the water-soluble alginate is 30,000-200,000, and the relative molecular weight is the ratio of the average mass of a molecule or a specific unit of a substance to 1/12 of the atomic mass of nuclide ¹² C. For example, the water-soluble alginate may be selected from one or more of sodium alginate, potassium alginate and ammonium alginate. Water-soluble alginates that meet the above requirements can be obtained commercially, for example, sodium alginate produced by Qingdao Nanyang Seaweed Industry Co., Ltd., potassium alginate produced by Qingdao Mingyue Seaweed Group Co., Ltd., and Handan Ocean Medicinal Seaweed Products Co., Ltd. Production of ammonium alginate.

The type of water-soluble alginate can be changed in a wide range, as long as the collision between molecules in the waste liquid can be intensified, and the small molecules that are not easy to precipitate can be combined into macromolecules to form larger flocs. Here, the relative molecular weight of the water-soluble alginate is 30,000-200,000, and the relative molecular weight is the ratio of the average mass of a molecule or a specific unit of a substance to 1/12 of the atomic mass of nuclide ¹² C. For example, the water-soluble alginate may be selected from one or more of propylene glycol alginate, ethylene glycol alginate and butylene glycol alginate, preferably propylene glycol alginate. Water-soluble alginate that meets the above requirements can be synthesized by methods known to those skilled in the art, or can be obtained commercially, for example, propylene glycol alginate produced by Qingdao Mingyue Seaweed Group Co., Ltd.

Preferably, water-soluble alginate and water-soluble alginate are added to the waste liquid before solid-liquid separation is carried out, and when adding water-soluble alginate and water-soluble alginate at the same time, the solid The time of liquid separation can further increase the treatment capacity of waste liquid per unit time. In this case, the amount of water-soluble alginate and water-soluble alginate can be changed in a wide range, preferably, with respect to 100 parts by weight of water-soluble alginate, the water-soluble alginate The addition amount of is 10-1000 parts by weight. Further preferably, relative to 100 parts by weight of the water-soluble alginate, the added amount of the water-soluble alginate is 40-300 parts by weight.

According to the present invention, the method for pulverizing potato raw materials can be various methods that can be used for pulverizing potato raw materials. For example, the pulverizing method of cassava may include mixing cassava with water and then pulverizing, but the method obtained The particle size of the pulverized potato raw material is relatively large and uneven, resulting in a lower yield of ethanol and a higher residual sugar rate. Therefore, preferably, the pulverizing method includes first pulverizing the potato raw material once , to obtain a primary pulverization product, and carry out secondary pulverization on part of the primary pulverization product to obtain a secondary pulverization product, mix the remaining part of the primary pulverization product with uncrushed potato raw materials and then perform primary pulverization; after solid-liquid separation of the waste liquid Water-soluble alginate and/or water-soluble alginate were previously added to the waste liquid.

According to the present invention, the primary crushed product of the remaining part is 5-20% by weight of the total primary crushed product; -20% by weight. Preferably, the primary crushed product of the remaining part is 5-10% by weight of the total primary crushed product weight; the primary crushed product of the remaining part accounts for 5% of the total weight of the primary crushed product of the remaining part and the unpulverized tuber raw material. -10% by weight. The particle size of the potato raw material particles in the final pulverized product obtained by pulverizing according to the method of the present invention is small and the particle size distribution is more uniform. The average particle diameter of the potato raw material can reach 1.8 to less than 2.5 mm, or even smaller, such as preferably 1.6 mm. to less than 1.8 mm.

According to the method provided by the present invention, before the potato raw material is crushed once, it is not necessary to mix the potato raw material with water, or only a small amount of water is added, for example, the amount of water can be 0.5-5% of the dry weight of the potato raw material. 2 times, preferably 1-1.5 times. Preferably, it is not necessary to mix the potato raw material with water before pulverizing the potato raw material. Instead, the part of the primary crushed product after the primary pulverization is returned to be remixed with the potato raw material that has not been pulverized, and then the primary pulverization is performed. The returned part of the primary crushed product is the starch slurry of potato raw material granules. The primary crushed product of this returned part can play a role of dilution, so the potato raw material can not be mixed with water during the initial crushing. In addition, the returned part The primary crushed product can be crushed again together with fresh cassava raw materials, not only consumes less water, consumes less energy, has high utilization rate of equipment, high crushing effect, and the secondary crushing method of the present invention can be very good Controlling the particle size of potato raw material particles in the pulverized product obtained after crushing, so that the particle size of the finally obtained potato raw material particles is small and uniform. According to the present invention, in order to make the diameter of the potato raw material particles in the finally obtained crushed product be 1.8 to less than 2.5 mm, preferably 1.6 to less than 1.8 mm, after primary crushing of the potato raw material, the obtained primary crushed product of potato The average particle diameter of the quasi-raw material is generally 2.5-10 mm, preferably 2.5-5 mm.

According to a specific embodiment of the present invention, when the feeding method is continuous feeding, the remaining part of the primary crushed product can be mixed with the uncrushed tuber raw material and the part of the primary crushed product after primary crushing can be taken out , continue to mix with the potato raw materials that have not been crushed and perform primary crushing, and perform circular and continuous crushing according to this method.

According to another specific embodiment of the present invention, when the feeding method is intermittent feeding, the remaining part of the primary pulverization product can be mixed with the raw potato raw materials that have not been pulverized and the primary pulverization product obtained after primary pulverization can be directly Secondary pulverization is performed to obtain a secondary pulverization product, and the primary pulverization product may be mixed with the primary pulverization product obtained after the primary pulverization to perform secondary pulverization together.

Conventional various crushing equipment can be used, such as SFSP series hammer mills.

The potato raw material can be various potato raw materials, such as sweet potato, potato, cassava, etc. The potato raw material adopted in the specific embodiment of the present invention is cassava. The cassava can be fresh cassava or dry cassava, or a mixture of fresh cassava and dry cassava. The weight of the dry cassava and the fresh cassava is not particularly limited. Usually, the weight ratio of the dry cassava to the fresh cassava is 1:1.5-2.5, preferably 1:1.5-2.

Mature cassava is generally 4-8 cm thick and 20-30 cm long. There are white ring-shaped stripes, and the inner bark and flesh are white. Since the potato raw materials may contain soil, sand and stone impurities and iron impurities, which will cause damage to the crushing equipment, therefore, according to the method of the present invention, it may also include the conventional operation of pretreating the potato raw materials before crushing. The steps of pretreatment generally include the steps of removing impurities and cleaning. For example, after the fresh cassava is harvested, impurities such as soil, roots, whiskers, woody parts, and sand and stones on the cassava are removed. And cassava is cleaned, and the method and equipment of described cleaning are known to those skilled in the art, do not repeat them here.

The enzymolysis step can be accomplished by methods commonly used in the art, such as adding enzyme-producing microorganisms and/or enzymes to the pulverized product, and incubating at the growth temperature of the enzyme-producing microorganisms and/or the temperature at which the enzymes are active. The enzyme-producing microorganism is an enzyme-producing microorganism capable of secreting amylase. The enzymes include amylases.

Direct addition of the enzyme is preferred due to by-products produced by microbial growth. The more the amount of the enzyme, the better, for cost considerations, preferably based on the dry weight per gram of the crushed product, the amount of the amylase is 4-50 enzyme activity units, more preferably per gram of the crushed product Based on the dry weight of the product, the amylase is used in an amount of 10-30 enzyme activity units.

The enzyme activity unit of the enzyme in the present invention is defined as: under the conditions of pH value 6.0 and temperature 70° C., the amount of enzyme required to convert 1 mg of starch into glucose in 1 minute is an enzyme activity unit.

The enzymolysis temperature can be any optimum action temperature of amylase, generally 50-90°C, more preferably 60-70°C. Theoretically, the longer the enzymatic hydrolysis time, the better. Considering the equipment utilization rate, the enzymatic hydrolysis time is preferably 20-240 minutes, more preferably 30-120 minutes. The pH value of the enzymatic hydrolysis can be any optimum action pH of amylase, generally 3-7, more preferably 5-6. Because the fluctuation of the pH value in the enzymolysis process is not large, the pH value of the enzymolysis can be adjusted according to the methods commonly used in the art before adding the enzyme, such as first mixing the pulverized product with water or culture medium (enzyme is generally mixed with water) Mixing, adding enzyme-producing microorganisms (generally mixed with the culture medium of the microorganisms), in addition, in order to ensure the concentration of ethanol obtained by distillation, generally the solid content of the resulting mixture is 20-40% by weight, according to the pH value of the resulting mixture, use sulfuric acid solution or sodium hydroxide to adjust the pH of the mixture to be hydrolyzed to 3-7, more preferably to pH 5-6.

Amylase is a general term for a class of enzymes capable of decomposing starch glycosidic bonds, and the amylase generally includes α-amylase, β-amylase, glucoamylase and isoamylase. The enzymes of the present invention include amylases.

α-amylase, also known as starch 1,4-dextrinase, can arbitrarily and irregularly cut the α-1,4-glucosidic bond inside the starch chain, and hydrolyze starch into maltose, which contains 6 glucose units. Oligosaccharides and branched oligosaccharides. The microorganisms producing this enzyme mainly include Bacillus subtilis, Aspergillus niger, Aspergillus oryzae and Rhizopus.

β-amylase, also known as starch 1,4-maltosidase, can cut 1,4-glucosidic bonds from the non-reducing ends of starch molecules to generate maltose. The products of this enzyme acting on starch are maltose and limit dextrin. This enzyme is mainly produced by Aspergillus, Rhizopus and Endospora.

Glucoamylase, also known as starch α-1,4-glucosidase, acts on the non-reducing end of the starch molecule, taking glucose as the unit, and acts on the α-1,4-glucosidic bond in the starch molecule in turn to generate glucose . The products of this enzyme after acting on amylopectin include glucose and oligosaccharides with α-1,6-glycosidic bonds; the products after acting on amylose are almost all glucose. The enzyme-producing bacteria are mainly Aspergillus niger (Aspergillus levomerus, Aspergillus awamori), Rhizopus (Rhizosimus nigeriensis, Rhizopus delbrueckii), Endospora, and Monascus.

Isoamylase, also known as starch α-1,6-glucosidase, branching enzyme, this enzyme acts on the α-1,6-glucosidic bond at the branch point of the amylopectin molecule, and the entire side chain of the amylopectin Cut into amylose. The enzyme-producing bacteria are mainly bacteria such as Aerobacter, Bacillus and some Pseudomonas.

Preferably, the enzymes used in the enzymolysis also include phosphatases. Because phosphatase can hydrolyze the phosphodextrin formed by the combination of phosphoric acid and alcoholic hydroxyl group into glucose, and release phosphoric acid, which has a very obvious liquefaction power, so the enzymes used in enzymatic hydrolysis include phosphatase, which can hydrolyze more fully starch to increase ethanol yield.

Microbes capable of fermenting monosaccharides such as glucose and/or fructose, oligosaccharides such as sucrose and/or galactose can be used in the fermentation process of the present invention, because Saccharomyces cerevisiae is alcohol-resistant, by-product few, ethanol that is generally used in the brewing industry Hexose-fermenting microorganisms with high yields, so it is preferred that the yeast used for the fermentation is Saccharomyces cerevisiae.

Calculated per gram of enzymatic hydrolysis product, the inoculum amount of yeast used in the fermentation is 10 ³ -10 ⁸ colony forming units, more preferably 10 ⁴ -10 ⁶ colony forming units.

The definition of the colony-forming unit is that a certain amount of diluted bacterial solution is poured or coated, and the microbial single cells in it are dispersed on the medium plate one by one. After culturing, each living cell will form a colony. That is, the number of single cells contained in each milliliter of bacterial liquid.

The yeast used for the fermentation of the present invention can be commercially available yeast solid preparations (such as dry yeast powder) or yeast strains, such as Lars No. 2 (Rasse II) yeast, also known as German No. 2 yeast, Rass No. 12 (Rasse XII) ) yeast, also known as German No. 12 yeast, K word yeast, Nanyang No. 5 yeast (1300) and Nanyang mixed yeast (1308). The colony forming unit of the yeast can be determined by methods known in the art, such as methylene blue staining viable count method. The specific method of methylene blue staining viable count method is as follows:

Dissolve 1 gram of dry yeast powder in 10 milliliters of sterile water, or dilute 1 milliliter of strain activation solution with sterile water to 10 milliliters, add 0.5 milliliters of 0.1 wt% methylene blue, and incubate at 35° C. for 30 minutes. Under a 10x optical microscope, use a hemocytometer to count the number of viable bacteria in the solution after incubation (dead bacteria are stained, live bacteria are not stained), and the number of viable bacteria in 1 gram of dry yeast or 1 ml of strain activation solution can be obtained , the number of colony-forming units.

The yeast can be inoculated by a conventional method, for example, adding 5-15 volume % seed liquid to the enzymatic hydrolysis product. The seed solution may be an aqueous solution or a culture medium solution of dry yeast, or may be an activated seed solution of dry yeast or commercially available strains.

The fermentation temperature can be any temperature suitable for yeast growth, preferably 30-36°C, more preferably 30-33°C. The pH is 4-6, preferably 4-4.5. The time of the fermentation can be the time from the beginning of inoculation to the decay phase of yeast growth (that is, the fermentation time is the lag phase, the logarithmic phase plus the stationary phase), and the preferred fermentation time is 50-75 hours, more preferably 60-75 hours. 70 hours. The fermentation product ethanol can be separated and refined according to the requirements of different industrial products (for example, fuel alcohol requires the purity of ethanol to be more than 99%) by conventional methods, such as distillation, concentration, and water removal.

According to the present invention, the solid product with a water content of less than 60% by weight can be obtained in various ways, for example, it can be obtained by filtering and pressing the waste liquid.

The inventors of the present invention have carried out careful research on the existing methods of recovering solid residues from the waste liquid produced by fermenting potato raw materials to produce ethanol, and found that in the prior art, ordinary filter presses are usually used to ferment potato raw materials to produce ethanol When filtering, the waste liquid enters between the ordinary filter plates of the filter press, the solid particles are trapped in the space between the filter plates by the filter medium of the filter plate, and the liquid passes through the filter medium and is discharged from the outlet hole. Outside the filter press, with the continuation of the filtration process, the thickness of the solid product gradually increases, and the dehydration resistance increases exponentially, resulting in a sharp drop in processing capacity, and due to the limitation of the nature of the ordinary filter plate itself, the filtration pressure cannot be further increased. (generally below 1MPa), so that the water content of the solid product cannot be further reduced.

According to the present invention, various equipment can be used to filter and squeeze the waste liquid, preferably, a diaphragm filter press can be used to achieve, the diaphragm filter press has the same filtering function as a common diaphragm filter press, and also has The function of pressing the solid product to dehydrate it again. In the diaphragm filter press, the ordinary filter plate and the diaphragm filter plate are arranged at intervals, and the middle core plate of the diaphragm filter plate is pressed with the diaphragms on both sides to form two sealed interlayers. , the filtration function of the diaphragm filter plate is the same as that of the ordinary filter plate, but the squeeze function is added, that is, after the filtration is completed, the squeeze medium is injected into the sealing layer from the inlet hole of the middle core plate, due to the elasticity of the diaphragm, it can The filtered solid product is subjected to bulge pressing to dehydrate the solid product again.

According to the present invention, the amount of water-soluble alginate and/or water-soluble alginate can be changed in a wide range, as long as the time of solid-liquid separation can be shortened, preferably, relative to 1000 parts by weight of waste Liquid, the consumption of water-soluble alginate and/or water-soluble alginate is 0.05-1 weight part; The consumption is 0.1-0.5 weight part.

The type of water-soluble alginate can be changed in a wide range, as long as the collision between molecules in the waste liquid can be intensified, and the small molecules that are not easy to precipitate can be combined into macromolecules to form larger flocs. Here, the relative molecular weight of the water-soluble alginate is 30,000-200,000, and the relative molecular weight is the ratio of the average mass of a molecule or a specific unit of a substance to 1/12 of the atomic mass of nuclide ¹² C. For example, the water-soluble alginate may be selected from one or more of sodium alginate, potassium alginate and ammonium alginate. Water-soluble alginates that meet the above requirements can be obtained commercially, for example, sodium alginate produced by Qingdao Nanyang Seaweed Industry Co., Ltd., potassium alginate produced by Qingdao Mingyue Seaweed Group Co., Ltd., and Handan Ocean Medicinal Seaweed Products Co., Ltd. Production of ammonium alginate.

The type of water-soluble alginate can be changed in a wide range, as long as the collision between molecules in the waste liquid can be intensified, and the small molecules that are not easy to precipitate can be combined into macromolecules to form larger flocs. Here, the relative molecular weight of the water-soluble alginate is 30,000-200,000, and the relative molecular weight is the ratio of the average mass of a molecule or a specific unit of a substance to 1/12 of the atomic mass of nuclide ¹² C. For example, the water-soluble alginate may be selected from one or more of propylene glycol alginate, ethylene glycol alginate and butylene glycol alginate, preferably propylene glycol alginate. Water-soluble alginate that meets the above requirements can be synthesized by methods known to those skilled in the art, or can be obtained commercially, for example, propylene glycol alginate produced by Qingdao Mingyue Seaweed Group Co., Ltd.

Preferably, water-soluble alginate and water-soluble alginate are added to the waste liquid before solid-liquid separation is carried out, and when adding water-soluble alginate and water-soluble alginate at the same time, the solid The time of liquid separation can further increase the treatment capacity of waste liquid per unit time. In this case, the amount of water-soluble alginate and water-soluble alginate can be changed in a wide range, preferably, with respect to 100 parts by weight of water-soluble alginate, the water-soluble alginate The addition amount of is 10-1000 parts by weight. Further preferably, relative to 100 parts by weight of the water-soluble alginate, the added amount of the water-soluble alginate is 40-300 parts by weight.

According to the present invention, the solid-liquid separation can be a variety of conventional solid-liquid separation methods, such as filtration, for example, can be filtered by a filter press, for example, the box filter press produced by Jingjin Filter Press Group Co., Ltd. machine. The filtering conditions can be changed in a wide range. Preferably, the filtering conditions include a filtering pressure of 0.4-1 MPa and a filtering time of 1-3 hours.

However, the inventors of the present invention have found that when using a common box-type filter press to filter the waste liquid produced by cassava fermentation to produce ethanol, the waste liquid enters between the box-type filter plates of the filter press, and the solid particles are filtered by the filter plates. The medium is trapped in the space between the filter plates, and the liquid passes through the filter medium and is discharged out of the filter press through the outlet hole. With the continuation of the filtration process, the thickness of the solid product gradually increases, and the dehydration resistance increases exponentially. It leads to a sharp drop in processing capacity, and due to the limitation of the nature of the box filter plate itself, the filtration pressure cannot be further increased (generally below 1MPa), so that the water content of the solid product cannot be further reduced, and the energy required for subsequent drying of the solid product higher consumption.

Therefore, preferably, the solid-liquid separation is achieved by filtering and squeezing the waste liquid.

According to the present invention, various devices can be used to filter and squeeze the waste liquid, preferably, a membrane filter press can be used to filter and squeeze the waste liquid.

The membrane filter press not only has the same filtering function as the ordinary box filter press, but also has the function of pressing the solid product to dehydrate it again. In the membrane filter press, the ordinary box filter plate and The diaphragm filter plates are arranged at intervals, and the middle core plate of the diaphragm filter plate is compressed with the diaphragms on both sides to form two sealed interlayers. The filtration function of the diaphragm filter plate is the same as that of the ordinary box filter plate, but the pressing function is added. That is, after the filtration is completed, the extrusion medium is injected into the sealing layer from the inlet hole of the middle core plate, and due to the elastic effect of the diaphragm, the filtered solid product can be expanded and squeezed to dehydrate the solid product again.

The number of common chamber filter plates and diaphragm filter plates in the membrane filter press can be adjusted according to the concentration of waste liquid. Preferably, the number of common chamber filter plates is 50-60, and the common The box-type filter plate can be commercially obtained, such as the box-type filter plate produced by Jingjin Filter Press Group Co., Ltd.; the number of diaphragm filter plates is 50-60, and the diaphragm filter plate can be obtained commercially, such as Jingjin The 1250-type diaphragm filter plate produced by Jin Filter Press Group Co., Ltd.; ordinary box filter plates and diaphragm filter plates are arranged at intervals and the ratio of the number of different box filter plates to the number of diaphragm filter plates is 1:1; The membrane filter press required above can be purchased commercially, for example, the X _M ^A ZG600/1500×2000U ^B _K type membrane filter press produced by Jingjin Filter Press Group Co., Ltd.

The inventors found that using a diaphragm filter press can not only significantly reduce the water content of the solid product obtained by pressing, but also greatly reduce the content of impurities in the water removed by pressing, reducing the wear and tear on the equipment by impurities and reducing maintenance costs. ; And the COD value in the removed water is also low, which reduces the environmental pressure.

In the present invention, the waste liquid produced by cassava fermentation to produce ethanol refers to the solid-liquid mixture remaining after distilling off the obtained ethanol when producing ethanol by cassava fermentation.

In the present invention, the conditions of the filtering and squeezing can be changed in a wide range, the conditions of the filtering and squeezing make the water content of the obtained solid product less than 60% by weight, preferably, the filtering conditions include filtering The pressure of the filter is 0.4-1MPa, and the time of filtering is 1-2 hours; the conditions of the squeezing include that the pressure of squeezing is 10-25MPa, and the time of squeezing is 0.2-1 hour.

In the present invention, the squeeze pressure can be realized by filling the squeeze medium in the membrane filter press, and the squeeze medium can be various squeeze mediums commonly used in the membrane filter press, for example, the squeeze medium Can be compressed air and/or water.

The method according to the present invention also includes drying the solid product obtained after solid-liquid separation to obtain a solid residue. The drying equipment can be various conventional drying equipment, for example, the HZG series drying equipment produced by Shenyang Yuanda Company. Dryer and WJI-900B boiling dryer and XLS-100 flash dryer combined dryer produced by Beijing Yimin Industry and Trade Co., Ltd. In the present invention, the drying conditions may be conventional drying conditions, for example, the drying conditions include a drying temperature of 100-200°C and a drying time of 0.2-2 hours; more preferably, drying The drying temperature is 120-150°C, and the drying time is 0.5-1 hour.

The present invention will be further specifically described below by way of examples.

Example 1

This example is used to illustrate the method for preparing ethanol using cassava raw material of the present invention.

(1) Crushing of cassava raw materials

95 kilograms of fresh cassava raw materials (4-8 centimeters thick, 20-30 centimeters long, water content 65% by weight) are cleaned and cut into discs about 1 centimeter thick, and then use the SFSP series hammer mill to treat the cassava chips Pulverize, the method of described pulverization comprises first this cassava chip of 60 kilograms is carried out primary pulverization 20 minutes, obtains the primary pulverization product 60 that average particle diameter is 4.5 millimeters (Accu Sizer TM780 optical particle diameter detector adopts U.S. PPS company to measure). 60 kilograms, then 60 kilograms of this primary pulverization product of 10 weight % is mixed with the remaining 35 kilograms of fresh cassava raw materials that have not been pulverized and carried out primary pulverization for 15 minutes again to obtain a primary pulverization product with an average particle diameter of 3 millimeters, and all of the above The primary crushed product was subjected to secondary crushing for 5 minutes to obtain 95 kg of a crushed product (the average particle diameter of the cassava raw material in the crushed product was 2 mm).

Take 10 grams of the above pulverized product, filter and dry at 45° C. to a constant weight of 3.4 grams, weigh 300.0 mg of the dried pulverized product, and place it in a 100 ml dry Erlenmeyer flask weighing 80 grams. Add 3.00 ml of sulfuric acid solution with a concentration of 72% by weight into the Erlenmeyer flask, and stir for 1 minute. The Erlenmeyer flask was then placed in a water bath at 30 °C for 60 minutes, stirring every 5 minutes to ensure uniform hydrolysis. After the hydrolysis, the concentration of sulfuric acid was diluted to 4% by weight with deionized water, and then filtered with a Buchner funnel to obtain a total of 84 ml of filtrate. Transfer 20 mL of the filtrate to a dry 50 mL Erlenmeyer flask. The pH value of the filtrate was adjusted to 5.5 with 2.5 g of calcium carbonate, allowed to stand for 5 hours, and the supernatant was collected. The collected supernatant was filtered with a 0.2 micron membrane filter, and the resulting filtrate was analyzed by Biorad AminexHPX-87P high performance liquid chromatography (HPLC). HPLC conditions: injection volume 20 microliters; mobile phase is HPLC ultrapure water filtered by 0.2 micron filter membrane and degassed by ultrasonic vibration; flow rate is 0.6 ml/min; column temperature 80-85°C; detector temperature 80-85°C ; The detector is a refractive index detector; the running time is 35 minutes. D-(+) glucose in the concentration range of 0.1-4.0 mg/ml is used as a standard sample. HPLC analysis obtains that the glucose concentration in the acid hydrolyzate of the pulverized product is 3.70 mg/ml, and the acid hydrolysis of 1 gram of the pulverized product can be calculated to obtain glucose with a weight of 0.311 grams, because the sulfuric acid solution with a concentration of 72% by weight can dilute the pulverized product The starch in the product is all hydrolyzed into glucose, so the weight of the glucose obtained is 1.11 times of the starch weight in the crushed product, that is, the starch content in 1 gram of the crushed product is 0.280 grams, and then 95 kg of the crushed product contains 26.6 kg of starch.

(2) Enzymolysis

Mix the pulverized product remaining after the sampling test in step (1) with 21 kg of water, adjust the pH value to 5, heat to 70°C, and add 20 enzyme activity units of α-amylase based on the dry weight of the pulverized product per gram (purchased by Novozymes), and the enzymolysis product was obtained after incubation at 70° C. for 60 minutes.

(3) fermentation

The temperature of the enzymatic hydrolyzate was lowered to 33°C, and inoculated with ¹⁰⁵ colony-forming units of alcoholic yeast (Anqi Super Saccharomyces cerevisiae high-activity dry yeast, Hubei Angel Yeast Co., Ltd. Stir and cultivate in a fermenter at 33°C for 65 hours, distill the resulting fermentation product at 100°C, and distill the distilled fraction at 78.3°C to obtain 13.73 kg of ethanol. The ethanol yield was calculated according to the following formula, and the calculation results are shown in Table 1.

Ethanol yield=100%×ethanol weight/weight of starch contained in cassava raw material

Take 100 grams of fermented mash after distilling ethanol and filter it with a Buchner funnel, transfer 20 milliliters of the filtrate to a dry 50 milliliter Erlenmeyer flask, let it stand for 5 hours, and collect the supernatant. The supernatant collected by 0.2 micron filter membrane filtration, according to the high-efficiency liquid phase conditions described in the above-mentioned steps (1), measure and calculate the total 372 grams of glucose in the fermented mash. And calculate the residual sugar rate according to the following formula, and the calculation results are shown in Table 1.

Residual sugar rate = 100% × amount of residual sugar in fermented mash / weight of starch contained in cassava raw materials

(4) Waste liquid treatment

The waste liquid produced by fermenting the potato material in the fermenter to produce ethanol is taken out from the fermenter, the fermenter is washed with water, and the taken out waste liquid is mixed with the washed water.

15 batches of the above-mentioned fermented waste liquids were mixed, and the water content in the mixed waste liquids was detected to be 95% by weight by a moisture analyzer (Shanghai Precision Scientific Instrument Co., Ltd., SH-10A). Add 10 kilograms of propylene glycol alginate (Qingdao Mingyue Seaweed Group Co., Ltd., relative molecular weight is 40000) to 100 tons of the above mixed waste liquid, and then add the waste liquid to the chamber filter press (Jingjin Filter Press Group Co., Ltd. ), the filter press is filled and filtered. In the box filter press, the number of common box filter plates (Jingjin Filter Press Group Co., Ltd., box filter plates) is 100, and the The conditions of filtration include that the pressure of filtration is 0.8MPa, and the time of filtration is 2 hours to obtain a solid product A1 with a water content of 75% by weight, the time required for solid-liquid separation and the waste liquid treatment capacity per unit time (single unit) As shown in table 2.

Comparative example 1

This comparative example illustrates a reference process for the production of ethanol from cassava.

Prepare ethanol according to the method of Example 1, the difference is that 95 kilograms of fresh cassava raw materials are mixed with 95 kilograms of water (the weight ratio of cassava raw material fresh weight and water is 1:1) and then pulverized once for 35 minutes, then pulverized once The product was directly subjected to secondary crushing for 5 minutes to obtain a total of 190 kg of crushed product (the average particle diameter of the cassava raw material in the crushed product was 5 mm). According to the high-efficiency liquid phase conditions described in step (1) of Example 1, it was measured and calculated that the 190 kg pulverized product contained 26.5 kg of starch.

Using the same conditions as in Example 1, the remaining pulverized product after the sampling test was enzymatically hydrolyzed, and the enzymolyzed product was fermented to obtain 13.38 kg of ethanol.

Take 100 grams of distilled ethanol and filter the remaining fermented mash with a Buchner funnel, transfer 20 milliliters of the filtrate to a dry 50 milliliter Erlenmeyer flask, let it stand for 5 hours, and collect the supernatant. The supernatant collected by 0.2 micron filter membrane filtration, according to the high-efficiency liquid phase conditions described in the above-mentioned steps (1), measure and calculate the total 583 grams of glucose in the fermented mash. And calculate ethanol production rate and residual sugar rate according to the formula of embodiment 1, calculation result is shown in table 1.

In addition, according to the same method as in Example 1, the waste liquid produced by cassava fermentation to ethanol was filtered, except that propylene glycol alginate was not added to obtain a reference solid product CA1 with a water content of 75% by weight, which was required for solid-liquid separation. The time and the waste liquid treatment capacity per unit time (single unit) are shown in Table 2.

Example 2

This example is used to illustrate the method for preparing ethanol using cassava raw material of the present invention.

Prepare ethanol according to the method of Example 1, the difference is that the pulverizing method includes using the SFSP series hammer mill to first pulverize 30 kilograms of fresh cassava raw materials for 12 minutes to obtain a primary pulverization with an average particle diameter of 5 mm. 30 kilograms of product, then 1.5 kilograms of this primary crushing product of 5% by weight is mixed with the remaining 25 kilograms of fresh cassava raw materials that have not been crushed and once again crushed for 10 minutes to obtain 55 kilograms of primary crushing products with an average particle diameter of 4 mm 2.75 kg of the primary crushed product of 5% by weight and the remaining 40 kg of cassava that have not been crushed were crushed once for 15 minutes to obtain 95 kg of the primary crushed product, and the above-mentioned primary crushed product was subjected to secondary crushing for 3 minutes. 95 kg of a pulverized product (the average particle diameter of the cassava raw material in the pulverized product was 2 mm) was obtained. According to the high-efficiency liquid phase condition described in embodiment 1 step (1), measure and calculate that this 95 kilograms of cassava slurry contains 26.8 kilograms of starch altogether.

Using the same conditions as in Example 1, the remaining pulverized product after the sampling test was enzymatically hydrolyzed, and the enzymolyzed product was fermented to obtain 14.07 kg of ethanol.

Take 100 grams of distilled ethanol and filter the remaining fermented mash with a Buchner funnel, transfer 20 milliliters of the filtrate to a dry 50 milliliter Erlenmeyer flask, let it stand for 5 hours, and collect the supernatant. The supernatant collected by 0.2 micron filter membrane filtration, according to the high-efficiency liquid phase conditions described in the above-mentioned steps (1), measure and calculate the total 348 grams of glucose in the fermented mash. And calculate ethanol production rate and residual sugar rate according to the formula of embodiment 1, calculation result is shown in table 1.

Waste liquid treatment

In step (4): the waste liquid produced by fermenting the tuber material in the fermenter to prepare ethanol is taken out from the fermenter, the fermenter is rinsed with water, and the waste liquid taken out is mixed with the washed water.

15 batches of the above-mentioned fermented waste liquids were mixed, and the water content in the mixed waste liquids was detected to be 95% by weight by a moisture analyzer (Shanghai Precision Scientific Instrument Co., Ltd., SH-10A). Add 20 kilograms of sodium alginate (Qingdao Nanyang Seaweed Industry Co., Ltd., relative molecular weight: 80,000) to 100 tons of the above mixed waste liquid, and then add the waste liquid to the chamber filter press (Jingjin Filter Press Group Co., Ltd.) Among them, the filter press is filled and filtered. In the box filter press, the number of common box filter plates (Jingjin Filter Press Group Co., Ltd., box filter plates) is 100. The filter The pressure that the condition comprises filtration is 0.8MPa, and the time of filtration is 1.8 hours, obtains water content and is the solid product A2 of 75% by weight, the time required for solid-liquid separation and the waste liquid treatment capacity (single unit) in unit time such as Table 1 shows.

Example 3

This example is used to illustrate the method for preparing ethanol using cassava raw material of the present invention.

Prepare ethanol according to the method of Example 1, the difference is that the pulverizing method includes using the SFSP series hammer mill to first pulverize 50 kilograms of fresh cassava for 15 minutes to obtain a pulverized product with an average particle diameter of 5.5 mm 50 kilograms, then 4 kilograms of this primary pulverization product of 8 weight % is mixed with the remaining 45 kilograms of fresh cassava raw materials that are not pulverized and pulverized once again for 15 minutes, and the pulverized product is mixed with the pulverized product after the first pulverization Obtaining 95 kilograms of primary crushed products with an average particle diameter of 4 mm, and performing secondary crushing on the above primary crushed products for 3 minutes to obtain 95 kg of crushed product cassava slurry (cassava raw material average particle diameter is 2 mm). According to the high-efficiency liquid phase conditions described in step (1) of Example 1, it was measured and calculated that the 95 kg pulverized product contained 26.6 kg of starch.

Using the same conditions as in Example 1, the remaining pulverized product after the sampling test was enzymatically hydrolyzed, and the enzymolyzed product was fermented to obtain 13.81 kg of ethanol.

Take 100 grams of distilled ethanol and filter the remaining fermented mash with a Buchner funnel, transfer 20 milliliters of the filtrate to a dry 50 milliliter Erlenmeyer flask, let it stand for 5 hours, and collect the supernatant. The supernatant collected by 0.2 micron filter membrane filtration, according to the high-efficiency liquid phase conditions described in the above-mentioned steps (1), measure and calculate the total 372 grams of glucose in the fermented mash. And calculate ethanol production rate and residual sugar rate according to the formula of embodiment 1, calculation result is shown in table 1.

Waste liquid treatment

The waste liquid produced by fermenting the potato material in the fermenter to produce ethanol is taken out from the fermenter, the fermenter is washed with water, and the taken out waste liquid is mixed with the washed water.

15 batches of the above-mentioned fermented waste liquids were mixed, and the water content in the mixed waste liquids was detected to be 95% by weight by a moisture analyzer (Shanghai Precision Scientific Instrument Co., Ltd., SH-10A). Add 10 kilograms of ammonium alginate (Handan Ocean Medicinal Seaweed Products Co., Ltd., relative molecular weight is 100000) and 10 kilograms of propylene glycol alginate (Qingdao Mingyue Seaweed Group Co., Ltd., relative molecular weight: 50000), then the waste liquid is added to the box filter press (Jingjin Filter Press Group Co., Ltd.), and the filter press is filled and then filtered. In the box filter press, the common box filter plate (Jingjin Filter Press Group Co., Ltd., box-type filter plate) was 100, and the filtration conditions included that the filtration pressure was 0.8 MPa, and the filtration time was 1.8 hours to obtain solid product A3.

The water content of the solid product A3 was detected by a moisture analyzer (Shanghai Precision Scientific Instrument Co., Ltd., SH-10A), and the results are shown in Table 3.

Put the obtained solid product A3 into an air-flow drum dryer (Zhengzhou Wangu Machinery Co., Ltd., JB/T10279-2001) for drying at a temperature of 180° C. to obtain a solid residue, which is determined by moisture content An instrument (Shanghai Precision Scientific Instrument Co., Ltd., SH-10A) detects the water content of the solid residue, and the water content of the solid residue and the energy consumption of drying are shown in Table 3.

The energy consumption refers to the coal consumed to dry and remove 1 kg of water, and the unit is kg/kg.

Example 4

This example is used to illustrate the method for preparing ethanol using cassava raw material of the present invention.

Prepare ethanol according to the method for Example 1, the difference is that 166 kilograms of mixture obtained after 61 kilograms of fresh cassava slices are mixed with 40 kilograms of dry cassava chips (water content is 13% by weight) and 65 kilograms of water are pulverized, pulverized The method comprises using a SFSP series hammer mill to first crush 40 kg of the cassava raw material mixture for 20 minutes to obtain 40 kg of the primary crushed product with an average particle diameter of cassava of 5.5 mm, and then crush 3.2 kg of the crushed product with 8% by weight Mix with 30 kilograms in the remaining cassava raw material mixture and carry out primary crushing 10 minutes again, obtain cassava average particle diameter and be 70 kilograms of primary crushing products of 5 millimeters altogether, this crushing product 7 kilograms of 10 weight % of this primary crushing products Carry out primary crushing 10 minutes again with 40 kilograms of mixtures in remaining cassava raw material mixture, obtain average particle diameter and be 110 kilograms of primary crushing products of 4 millimeters altogether, this primary crushing product 6.6 kilograms of this crushing product of 6 weight % is mixed again 56 kilograms of mixtures in the remaining cassava raw material mixture were pulverized once for 10 minutes to obtain 166 kilograms of primary pulverized products with an average particle diameter of 2.5 millimeters, and all of the above-mentioned pulverized products were carried out secondary pulverized for 5 minutes to obtain 166 kilograms of pulverized products ( The average particle diameter of the cassava raw material in this pulverized product was 1.6 mm). According to the high-efficiency liquid phase conditions described in step (1) of Example 1, it was measured and calculated that 166 kg of pulverized products contained 43.65 kg of starch.

The pulverized product after sampling and testing was enzymatically hydrolyzed using the same conditions as in Example 1. The difference was that the amount of water added during enzymolysis was 30 kg, and the enzymolyzed product was fermented to obtain 23.09 kg of ethanol.

Take 100 grams of distilled ethanol and filter the remaining fermented mash with a Buchner funnel, transfer 20 milliliters of the filtrate to a dry 50 milliliter Erlenmeyer flask, let it stand for 5 hours, and collect the supernatant. The supernatant collected by 0.2 micron filter membrane filtration, according to the high-efficiency liquid phase conditions described in the above-mentioned steps (1), measure and calculate the total 592 grams of glucose in the fermented mash. And calculate ethanol production rate and residual sugar rate according to the formula of embodiment 1, calculation result is shown in table 1.

Waste liquid treatment

According to the same method as Example 3, the waste liquid prepared by cassava fermentation to ethanol is filtered, the difference is that the waste liquid is added to a membrane filter press (Jingjin Filter Press Group Co., Ltd., X _M ^A ZG600/1500 × 2000U ^B Carry out solid-liquid separation in _K ), in described diaphragm filter press, replace 50 common chamber filter plates (Jingjin filter press) with 50 diaphragm filter plates (Jingjin Filter Press Group Co., Ltd., 1250 type) Group Co., Ltd., box-type filter plate), and the common box-type filter plate and the diaphragm filter plate are arranged at intervals; the conditions of the filtration include that the pressure of filtration is 0.8MPa, and the time of filtration is 1 hour; after that, in the membrane filter plate Fill the squeeze medium with air, and squeeze the filtered solid product, the pressure of the squeeze is 10 MPa, and the squeeze time is 0.8 hours, to obtain the solid product A4.

The water content of the solid product A4 was detected by a moisture analyzer (Shanghai Precision Scientific Instrument Co., Ltd., SH-10A), and the results are shown in Table 2.

Put the obtained solid product A4 into an air-flow drum dryer (Zhengzhou Wangu Machinery Co., Ltd., JB/T10279-2001) for drying. The drying temperature is 120° C. to obtain a solid residue, which is determined by moisture content An instrument (Shanghai Precision Scientific Instrument Co., Ltd., SH-10A) detects the water content of the solid residue, and the water content of the solid residue and the energy consumption of drying are shown in Table 2.

The energy consumption refers to the coal consumed to dry and remove 1 kg of water, and the unit is kg/kg.

Table 1

Examples or comparative examples Example 1 Comparative example 1 Example 2 Example 3 Example 4 Ethanol yield (%) 51.6 50.5 52.5 51.9 52.9 Residual sugar rate (%) 1.4 2.2 1.3 1.4 1.35

The method of the present invention not only consumes less water, but can complete the crushing in a short time, consumes less energy, has a higher utilization rate of the equipment, and has a higher crushing efficiency. Control the particle size of potato raw material particles in the pulverized product obtained after crushing, so that the particle size of the finally obtained potato raw material particles is small and uniform.

As can be seen from the data in the above table 1, the starch ethanol yield of ethanol obtained by the method for preparing ethanol from potato raw materials provided by the invention is significantly higher than the starch ethanol yield of the reference method, and is different from that of the prior art In comparison, the residual sugar rate of the method for preparing ethanol of the present invention is greatly reduced.

Table 2

Example number Solid product number Moisture content of solid product Time-consuming solid-liquid separation Capacity (tons/hour) Example 1 A1 75% by weight 2 hours 42 Comparative example 1 CA1 75% by weight 4.5 hours 18.7 Example 2 A2 75% by weight 1.8 hours 46.7

As can be seen from the above table 2, the method for reclaiming solid residues from the waste liquid of ethanol produced by cassava fermentation of the present invention significantly shortens the time of solid-liquid separation, and significantly improves the unit time without adding new equipment. The processing capacity of the internal waste liquid is reduced, thereby solving the bottleneck of the lower operating load of the device for producing ethanol by cassava fermentation, and improving the production capacity of the device for producing ethanol by cassava fermentation.

table 3

Example number Water content of solid product (weight%) Moisture content of solid residue (weight%) Energy consumption (kg/kg) Example 3 74% by weight 10% by weight 0.31 Example 4 55% by weight 10% by weight 0.12

As can be seen from the above table 3, the water content of the solid product A4 obtained in Example 4 of the present invention is 55% by weight, while the water content of the solid product A3 obtained in Example 3 is as high as 74% by weight. The machine can significantly reduce the water content of the solid product obtained by filtering and squeezing the waste liquid, and compared with Example 3, the energy consumption required for drying is greatly reduced in Example 4, which shows that by using membrane filter press Filtering and pressing the waste liquid by the machine can greatly reduce the energy consumption required to recover the solid residue.

Claims (14)

1. one kind is adopted potato raw material to prepare the alcoholic acid method, and this method comprises pulverizes potato raw material, with the product after pulverizing mix with enzyme, enzymolysis, obtain enzymolysis product; This enzymolysis product ferments; Separating alcohol from tunning; Then waste liquid is carried out solid-liquid separation, it is characterized in that, before waste liquid being carried out solid-liquid separation, in waste liquid, add water soluble algae acid esters and water soluble algae hydrochlorate; With respect to the water soluble algae acid esters of 100 weight parts, the add-on of said water soluble algae hydrochlorate is the 10-1000 weight part; The method of said pulverizing comprises once to be pulverized potato raw material earlier; Obtain crushed products one time; Crushed products of part is carried out secondary pulverize, obtain the secondary crushed products, a crushed products of remainder is mixed then with the potato raw material of not pulverizing once pulverize; The 5-20 weight % that a crushed products of remainder is whole crushed products weight; A crushed products of remainder accounts for the 5-20 weight % of crushed products of remainder and the gross weight of the potato raw material of not pulverizing.

2. method according to claim 1, wherein, with respect to the waste liquid of 1000 weight parts, the consumption of said water soluble algae acid esters and water soluble algae hydrochlorate is the 0.05-1 weight part.

3. method according to claim 2, wherein, with respect to the waste liquid of 1000 weight parts, the consumption of said water soluble algae acid esters and water soluble algae hydrochlorate is the 0.1-0.5 weight part.

4. method according to claim 1, wherein, with respect to the water soluble algae acid esters of 100 weight parts, the add-on of said water soluble algae hydrochlorate is the 40-300 weight part.

5. according to any described method among the claim 1-4; Wherein, The relative molecular weight of said water soluble algae hydrochlorate is 30000-200000; Said water soluble algae hydrochlorate is selected from one or more in sodium-alginate, potassium alginate and the ammonium alginate, and the relative molecular weight of said water soluble algae acid esters is 30000-200000, and said water soluble algae acid esters is a propylene glycol alginate.

6. method according to claim 1, wherein, the 5-10 weight % that a crushed products of remainder is whole crushed products weight; A crushed products of remainder accounts for the 5-10 weight % of crushed products of remainder and the gross weight of the potato raw material of not pulverizing.

7. method according to claim 1, wherein, in the crushed products, the average particulate diameter of potato raw material is the 2-10 millimeter; In the secondary crushed products, the average particulate diameter of potato raw material be 1.6 millimeters to less than 2 millimeters.

8. method according to claim 1, wherein, said solid-liquid separation is through filtering and squeeze realization to said waste liquid.

9. method according to claim 8, wherein, said filtration and squeezing realize that through diaphragm filter press the condition of said filtering condition and said squeezing makes the water cut of the solid product that obtains less than 60 weight %.

10. method according to claim 9, wherein, said filtering condition comprises that filtering pressure is 0.4-1MPa, filter time is 1-2 hour; The condition of said squeezing comprises that the pressure of squeezing is 10-25MPa, and the time of squeezing is 0.2-1 hour.

11. method according to claim 1, wherein, said potato raw material is the mixture of fresh cassava and dried cassava, and the weight ratio of said dried cassava and fresh cassava is 1: 1.5-2.5.

12. method according to claim 1, wherein, the enzyme that said enzymolysis uses comprises glycase, and with the dry weight basis of every gram potato raw material, said diastatic consumption is the 3.8-4.2 enzyme activity unit; The temperature of said enzymolysis is 50-90 ℃, and the time of said enzymolysis is 20-70 minute, and the pH value of said enzymolysis is 5-6.

13. method according to claim 12, wherein, said glycase is one or more in AMS, beta-amylase, saccharifying enzyme and the isoamylase.

14. method according to claim 1, wherein, in every gram enzymolysis product, the employed zymic inoculum size of said fermentation is 10 ³-10 ⁸Colony-forming unit, the temperature of said fermentation are 30-33 ℃, and the time of fermentation is 50-75 hour.