Background
The beet sugar manufacturing process mainly comprises the procedures of vegetable washing, shredding, juice extracting, clarifying, evaporating concentration, evaporating crystallization, molasses separation, white granulated sugar packaging and the like. Because non-sugar components in beet juice, including suspended particles, pigment substances, salt substances, reducing sugar, pectin, betaine, etc., affect the quality of sugar products and increase the amount of waste honey and sugar loss, it is necessary to clarify the juice before concentrating and crystallizing the juice, and remove non-sugar impurities as much as possible to improve the purity of the juice, reduce the viscosity and color value, and prepare high-quality raw syrup for boiling sugar. The sugar juice clarifying process is the most important process in the sugar production process, and the quality and yield of the white granulated sugar are directly determined by the clarifying effect. The prior sugar juice clarifying procedure has the following defects.
(1) The sugar beet has more pectin content which is about 2.5-10% of sugar beet, and part of pectin is hydrolyzed in the sugar exudation section, thus having great influence on sugar production: increasing the viscosity of the sugar solution and reducing the filterability thereof; the cleaning effect is affected, and the cleaning cost is increased; the growth of sucrose crystals is hindered, and the crystallization rate is affected; the pectin is removed as much as possible before evaporation and crystallization. Currently sugar juice clarification is achieved by adding clarifiers, commonly used ones are quicklime, carbon dioxide and sulphur dioxide. According to the difference of the main clarifying agents, the sugar juice clarifying process comprises three types of a carbonic acid method, a sulfurous acid method and a lime method. At present, sugar juice is clarified by a double-carbonic acid method in beet sugar factories, 30-45% of non-sugar in exuded juice can be removed generally, the efficiency is too low, lime consumption is high, a large amount of lime mud is difficult to treat, and environmental pollution is serious.
(2) The clear juice has insufficient brix, and the main non-sugar components in the clear juice have higher content, including inorganic salt, nitrogenous substances, reducing sugar and the like, and the subsequent evaporation has heavy load, high energy consumption and low sugar manufacturing efficiency.
(3) Since the vaporization latent heat of water is high, evaporation of water consumes a large amount of heat energy and fuel, resulting in an increase in production cost; in addition, in the traditional evaporation concentration process, the evaporation temperature is 125-135 ℃, the retention time of the sugar juice is long, the sugar juice is easy to degrade at a long time and high temperature, the color is deepened, the quality of the sugar juice is reduced, and finally the quality of a product can be influenced.
Disclosure of Invention
In order to solve the problems, the invention improves a system and a process for producing beet sugar by using a continuous membrane.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
the utility model provides a system for continuous membrane production beet sugar, includes juice extractor, liquid cyclone I, high frequency vibration sieve I, the blender, static mixer, liquid cyclone II, high frequency vibration sieve II, milipore filter, nanofiltration membrane, reverse osmosis membrane group, evaporimeter and crystallizer, the liquid outlet of juice extractor links to each other with liquid inlet of liquid cyclone I, liquid outlet of liquid cyclone I links to each other with liquid inlet of high frequency vibration sieve I, liquid outlet of high frequency vibration sieve links to each other with the liquid inlet of blender, liquid outlet of blender links to each other with static mixer's liquid inlet, static mixer's liquid outlet links to each other with liquid inlet of liquid cyclone II, liquid outlet of liquid cyclone II links to each other with the liquid inlet of milipore filter, the liquid outlet of milipore filter links to each other with the liquid inlet of nanofiltration membrane, liquid outlet of nanofiltration membrane links to each other with the liquid inlet of reverse osmosis membrane group, liquid outlet of reverse osmosis membrane group links to each other with the liquid inlet of evaporimeter, liquid outlet of evaporimeter links to each other with the liquid outlet of evaporimeter.
Further, a receiver is arranged at the discharge port of the lower end of the liquid cyclone I, and a slag liquid groove is arranged at the discharge port of the lower end of the liquid cyclone II.
Further, the molecular weight cut-off of the ultrafiltration membrane is 10000Da.
Further, the molecular weight cut-off of the nanofiltration membrane is 200Da-500Da.
Further, the molecular weight cut-off of the nanofiltration membrane is 350Da.
Further, the crystallization mother liquor tank is connected with a crystallizer liquid outlet.
Further, the ultrafiltration membrane adopts a membrane element disclosed in patent No. ZL201210582629.2, and the nanofiltration membrane adopts a membrane element disclosed in patent No. ZL 201210582629.2.
A method for producing beet sugar based on the continuous film of the above system, comprising the steps of:
(1) Pretreatment: washing beet, shredding, and extracting sugar from beet in a exudation device with water to obtain beet juice;
(2) Removing impurities: removing large-particle impurities in the beet juice by adopting a liquid cyclone I, and removing small-particle impurities in the beet juice by adopting a high-frequency vibration screen I, wherein the coupling operation temperature of the liquid cyclone I and the high-frequency vibration screen I is 60-70 ℃;
(3) Enzymolysis: uniformly mixing the beet juice after impurity removal with compound enzyme in a mixer, then carrying out continuous enzymolysis in a static mixer, and allowing the mixed solution after enzymolysis to enter a cyclone II;
(4) Membrane filtration and impurity removal: removing particles from beet juice from the upper part of a liquid cyclone II through a high-frequency vibration screen II to obtain clear filtrate, wherein the passing mesh of the high-frequency vibration screen II is 1000 meshes; removing large-particle impurities such as pectin by ultrafiltration membrane.
(5) Separation of mono-disaccharides: treating the filtering liquid with an ultrafiltration membrane to obtain clear and clean beet sugar juice, wherein the ultrafiltration membrane is made of polyvinylidene fluoride; filtering the beet sugar juice by nanofiltration membrane treatment to remove monosaccharide to obtain primary concentrated sugar juice;
(6) Concentrating and crystallizing: treating the primary concentrated sugar juice by a reverse osmosis membrane group at 75-85 ℃ and 3-4MPa, further concentrating by an evaporator at 90-100 ℃ to obtain a high-concentration concentrated solution, and crystallizing the high-concentration concentrated solution in a crystallizer.
Further, the complex enzyme consists of pectase and amylase, wherein the mass ratio of pectase to amylase is 4:1, and the adding amount of the complex enzyme is 10-30mg of complex enzyme added into each 1L of beet juice.
Compared with the prior art, the invention has the beneficial effects that:
compared with clear juice of the traditional process, the sugar degree of the obtained pre-concentrated juice is improved by 10 to 16 weight percent, meanwhile, the purity is improved by 3 percentage points, in addition, the improvement of the sugar degree can reduce the evaporation load by 60 to 70 percent, the efficiency is improved, and the cost is reduced; the invention adopts a biological method, and uses compound enzyme to degrade pectin and starch in beet juice, thereby reducing the viscosity of sugar juice and facilitating clarification and filtration; the invention carries out pre-concentration by a reverse osmosis membrane system, improves the brix of the dilute juice from 12wt% to about 50wt%, and then enters an evaporator to be continuously concentrated to 70wt%, the sugar juice after pre-concentration is reduced by about 70% of water, and only about 30% of water enters a multi-effect evaporation system, so that the energy consumption of evaporation concentration is also reduced by 70%; meanwhile, the retention time of the sugar juice in the evaporating pot is short, the risks of sugar juice degradation and color deepening are reduced, and the quality of the product is high. The operation temperature is 75-85 ℃, the viscosity of the sugar solution is reduced, and the membrane concentration efficiency is improved. The temperature is improved, the operating pressure of the membrane is low, the permeation quantity is large, the concentration of the pre-concentrated juice is high, and the process is operated under the medium pressure of 3-4MPa, so that the cost and the operation cost are low; compared with the traditional process, the process provided by the invention can greatly reduce the chromaticity and turbidity of the sugar juice, can also greatly reduce the content of non-sugar macromolecular substances in the sugar juice, and can improve the purity and yield of sucrose, and no clarifying agent such as lime is added in the main process.
Detailed Description
For a clearer understanding of technical features, objects and effects of the present invention, a specific embodiment of the present invention will be described with reference to the accompanying drawings, but the scope of the present invention is not limited to the following.
Examples
A system for producing beet sugar by continuous membrane comprises a juice infiltrating device 1, a pump I2, a liquid cyclone I3, a high-frequency vibrating screen I5, a pump II 6, a mixer 7, a static mixer 8, a liquid cyclone II 9, a high-frequency vibrating screen II 11, a pump III 13, an ultrafiltration membrane 14, a nanofiltration membrane 15, a pump IV 17, a reverse osmosis membrane group 18, an evaporator 19 and a crystallizer 20;
the liquid outlet pipeline of the juice extractor 1 is connected with the liquid inlet of the liquid cyclone I3, the pump I2 is arranged between the juice extractor 1 and the liquid cyclone I3, the liquid outlet at the upper end of the liquid cyclone I3 is connected with the liquid inlet of the high-frequency vibrating screen I5 through a pipeline, the liquid outlet of the high-frequency vibrating screen I5 is connected with the liquid inlet of the mixer 7 through a pipeline, the pump II 6 is arranged between the high-frequency vibrating screen I5 and the mixer 7, the liquid outlet of the mixer 7 is connected with the liquid inlet of the static mixer 8 through a pipeline, the liquid outlet of the static mixer 8 is connected with the liquid inlet of the liquid cyclone II 9 through a pipeline, the liquid outlet at the upper end of the liquid cyclone II 9 is connected with the liquid inlet of the high-frequency vibrating screen II 11 through a pipeline, the liquid outlet of the high-frequency vibrating screen II 11 is connected with the liquid inlet of the ultrafiltration membrane 14, the liquid outlet of the ultrafiltration membrane 14 is connected with the liquid inlet of the nanofiltration membrane 15 through a pipeline, the liquid outlet of the reverse osmosis membrane 18 is connected with the liquid inlet of the reverse osmosis membrane 18, the liquid outlet of the reverse osmosis membrane 18 is connected with the evaporator 19, and the liquid outlet of the evaporator 19 is connected with the liquid inlet of the reverse osmosis membrane 18.
The working process of the embodiment is as follows: the pump I2 pumps the beet juice flowing out of the juice permeation device 1 into the liquid cyclone I3, and the liquid cyclone I3 removes the sediment, the vegetable slag and other large-particle impurities in the beet juice; the beet juice from which the large-particle impurities are removed flows out through a liquid outlet at the upper end of the liquid cyclone I3 and enters a high-frequency vibrating screen I5, the high-frequency vibrating screen I5 removes the tiny particle impurities in the beet juice, and the large-particle impurities separated by the liquid cyclone I3 flow out from a discharge outlet at the lower end of the liquid cyclone I3; pumping beet juice flowing out from a liquid outlet of a high-frequency vibrating screen I5 into a mixer 7 by a pump II 6, uniformly mixing the beet juice with the compound enzyme by the mixer 7, allowing the beet juice mixed with the compound enzyme to flow into a static mixer 8 for continuous enzymolysis, degrading impurities such as pectin in the beet juice, allowing the enzymolyzed mixed liquid to flow into a liquid cyclone II 9, separating the mixed liquid by the liquid cyclone II 9, allowing the beet juice flowing out from a liquid outlet at the upper end of the liquid cyclone II 9 to flow into a high-frequency vibrating screen II 11, and allowing a liquid outlet at the lower end of the liquid cyclone II 9 to flow out of filter residues; the beet juice treated by the high-frequency vibrating screen II 11 flows into a juice groove 12; pumping beet juice in a sugar juice tank 12 into an ultrafiltration membrane 14 by a pump III 13, wherein the ultrafiltration membrane 14 is a membrane element disclosed in patent number ZL201210582629.2 with the cutoff molecular weight of 10000Da, the membrane material is polyvinylidene fluoride, macromolecular impurities and pigments in the beet juice are filtered out of the ultrafiltration membrane 14, so that clear and clean beet juice ultrafiltrate is obtained, most of the ultrafiltrate is sucrose, but part of monosaccharide and non-sugar components are still present; the beet juice ultrafiltrate enters a nanofiltration membrane 15, the nanofiltration membrane 15 adopts a membrane element disclosed in patent number ZL201210582629.2, the molecular weight cut-off is 200Da-500Da, more preferably 350Da, partial water molecules, monosaccharides and small molecular non-sugar impurities in the beet juice ultrafiltrate are removed, the disaccharide cut-off rate is kept to be 99.5%, 24wt% of beet juice is obtained, the beet juice treated by the nanofiltration membrane 15 flows into a storage tank 16, a pump IV 17 pumps the beet juice in the storage tank 16 into a reverse osmosis membrane group 18, the reverse osmosis membrane group 18 pre-concentrates the beet juice, the brix of the beet juice is increased from 24wt% to about 50wt%, the pre-concentrated beet juice enters an evaporator 19 to be concentrated to 70wt%, and 70wt% of the sugar juice enters a crystallizer 20 for crystallization.
The system of the invention avoids evaporating water, consuming a great amount of heat energy and fuel, resulting in increased production cost. In addition, in the traditional evaporation concentration process, the evaporation temperature (125-135 ℃) is high, the retention time of the sugar juice is long, the sugar juice is easy to degrade at a long time and at a high temperature, the color is deepened, the quality of the sugar juice is reduced, and finally the quality of a product can be influenced. The concentration of the diluted juice is improved from 24wt% to about 50wt% by a two-stage reverse osmosis membrane system, the obtained concentrated solution of the beet sugar juice is sent to a five-effect evaporator for concentration, the sugar degree is concentrated from 50% to 70%, the concentration temperature is 90-100 ℃, the 70% beet sugar concentrated solution is obtained, the high-temperature evaporation time is reduced, the risks of sugar juice degradation and color deepening are reduced, and the quality of the product is high.
Further, a receiver 4 is arranged below the hydrocyclone I3, and waste residues flowing out from a discharge port at the lower end of the hydrocyclone I3 are collected; a slag liquid groove 10 is arranged below the liquid cyclone II 9, and slag liquid flowing out from a discharge hole at the lower end of the liquid cyclone II 9 is collected.
Further, a crystallization mother liquor tank 21 is provided, and the crystallization mother liquor tank 21 is connected to a liquid outlet of the crystallizer 20 for collecting crystallization mother liquor.
The invention also comprises a method for producing beet sugar by using the continuous membrane based on the system.
Example 1
A method for producing beet sugar based on the continuous film of the above system, comprising the steps of:
(1) Pretreatment: washing and shredding beet, and extracting sugar in beet in a exuder 1 with water as solvent to obtain beet juice;
(2) Removing impurities: removing large-particle impurities such as sediment and vegetable slag mixed in the beet juice by adopting a liquid cyclone I3, and removing small-particle impurities in the beet juice by adopting a high-frequency vibrating screen I5, wherein the coupling operation temperature of the liquid cyclone I3 and the high-frequency vibrating screen I5 is 60 ℃;
(3) Enzymolysis: uniformly mixing the beet juice after impurity removal with compound enzyme in a mixer 7, wherein the compound enzyme consists of pectase and amylase, the mass ratio of pectase to amylase is 4:1, 10mg of compound enzyme is added into each 1L of beet juice, the mixed solution of the compound enzyme and the beet juice is subjected to continuous enzymolysis in a static mixer 8, impurities such as pectin in the beet juice are degraded, and the mixed solution after enzymolysis enters a cyclone II 9;
(4) Membrane filtration and impurity removal: removing particles from beet juice coming out of the upper part of a hydrocyclone II 9 through a high-frequency vibrating screen II to obtain clear filtrate, wherein the passing mesh of the high-frequency vibrating screen II is 1000 meshes; removing large-particle impurities such as pectin by ultrafiltration membrane.
(5) Separation of mono-disaccharides: treating the filtering liquid with an ultrafiltration membrane, and filtering out macromolecular impurities and pigments to obtain clear beet sugar juice; the beet sugar juice is treated by a nanofiltration membrane 15 to remove partial water molecules, monosaccharides and small molecular non-sugar impurities, the rejection rate of disaccharides reaches 99.5%, and the sugar juice is primarily concentrated to 24wt% of sugar degree;
(6) Concentrating and crystallizing: treating the primary concentrated sugar juice by a reverse osmosis membrane group 18 at the temperature of 75 ℃ and the pressure of 3MPa, and concentrating the sugar juice from 24wt% of sugar degree to 50wt%; the permeate water is purified water and can be reused in the production process; concentrating to sugar degree of 50wt% beet sugar juice, and feeding into evaporator 19 for further concentration at 90deg.C to obtain sugar degree of 70%; crystallizing, separating and drying by conventional method to obtain beet sugar product.
The treatment of the invention is compared with the material before entering the evaporator after the treatment by the traditional double carbonic acid method
Treatment method
|
Sugar degree (wt%)
|
Purity (%)
|
Evaporating to sugar degree of 50wt% steam consumption (t/t)
|
Bicarbonic acid process
|
13
|
88.4
|
1.707
|
The invention is that
|
50
|
92
|
0 |
The invention is used for pre-evaporating to the sugar degree of 50wt%, and for the traditional multi-effect evaporation process, the novel process combining the technology and the multi-effect evaporation can save energy by 70%.1 ton beet sugar is concentrated from 13wt% of dilute juice to 50wt%, 5.69 tons of water are required to be evaporated, the steam consumption is 0.3t/t according to 5-effect evaporation, and the steam consumption is 120 yuan/t, and then 5.69.3.120= 204.84 yuan is required for 1 ton beet sugar. The method of the invention can save 204.84-5.69 x 10 = 147.94 yuan for evaporating 1 ton of water, and can save 739.7 ten thousand yuan for evaporating 1 ton of water per ton of water according to 5 ten thousand tons of granulated sugar produced each year, and the lime treatment and the elimination of lime kiln are omitted, and the environmental protection cost is not counted.
Example two
A method for producing beet sugar based on the continuous film of the above system, comprising the steps of:
(1) Pretreatment: washing and shredding beet, and extracting sugar in beet in a exuder 1 with water as solvent to obtain beet juice;
(2) Removing impurities: removing large-particle impurities such as sediment and vegetable slag mixed in the beet juice by adopting a liquid cyclone I3, and removing small-particle impurities in the beet juice by adopting a high-frequency vibrating screen I5, wherein the operation temperature of coupling the liquid cyclone I3 and the high-frequency vibrating screen I5 is 70 ℃;
(3) Enzymolysis: uniformly mixing the beet juice after impurity removal with compound enzyme in a mixer 7, wherein the compound enzyme consists of pectase and amylase, the mass ratio of pectase to amylase is 4:1, 10mg of compound enzyme is added into each 1L of beet juice, the mixed solution of the compound enzyme and the beet juice is subjected to continuous enzymolysis in a static mixer 8, impurities such as pectin in the beet juice are degraded, and the mixed solution after enzymolysis enters a cyclone II 9;
(4) Membrane filtration and impurity removal: removing particles from beet juice coming out of the upper part of a hydrocyclone II 9 through a high-frequency vibrating screen II to obtain clear filtrate, wherein the passing mesh of the high-frequency vibrating screen II is 1000 meshes; removing large-particle impurities such as pectin by ultrafiltration membrane.
(5) Separation of mono-disaccharides: treating the filtering liquid with an ultrafiltration membrane, and filtering out macromolecular impurities and pigments to obtain clear beet sugar juice; the beet sugar juice is treated by a nanofiltration membrane 15 to remove partial water molecules, monosaccharides and small molecular non-sugar impurities, the rejection rate of disaccharides reaches 99.5%, and the sugar juice is primarily concentrated to 24wt% of sugar degree;
(6) Concentrating and crystallizing: treating the primary concentrated sugar juice by a reverse osmosis membrane group 18 at the temperature of 85 ℃ and the pressure of 4MPa, and concentrating the sugar juice from 15wt% of sugar degree to 50wt%; the permeate water is purified water and can be reused in the production process; concentrating to sugar degree of 50wt% beet sugar juice, and feeding into evaporator 19 for further concentration at 100deg.C to obtain sugar degree of 70%; crystallizing, separating and drying by conventional method to obtain beet sugar product.
Example III
A method for producing beet sugar based on the continuous film of the above system, comprising the steps of:
(1) Pretreatment: washing and shredding beet, and extracting sugar in beet in a exuder 1 with water as solvent to obtain beet juice;
(2) Removing impurities: removing large-particle impurities such as sediment and vegetable slag mixed in the beet juice by adopting a liquid cyclone I3, and removing small-particle impurities in the beet juice by adopting a high-frequency vibrating screen I5, wherein the coupling operation temperature of the liquid cyclone I3 and the high-frequency vibrating screen I5 is 65 ℃;
(3) Enzymolysis: uniformly mixing the beet juice after impurity removal with compound enzyme in a mixer 7, wherein the compound enzyme consists of pectase and amylase, the mass ratio of pectase to amylase is 4:1, 10mg of compound enzyme is added into each 1L of beet juice, the mixed solution of the compound enzyme and the beet juice is subjected to continuous enzymolysis in a static mixer 8, impurities such as pectin in the beet juice are degraded, and the mixed solution after enzymolysis enters a cyclone II 9;
(4) Membrane filtration and impurity removal: removing particles from beet juice coming out of the upper part of a hydrocyclone II 9 through a high-frequency vibrating screen II to obtain clear filtrate, wherein the passing mesh of the high-frequency vibrating screen II is 1000 meshes; removing large-particle impurities such as pectin by ultrafiltration membrane.
(5) Separation of mono-disaccharides: treating the filtering liquid with an ultrafiltration membrane, and filtering out macromolecular impurities and pigments to obtain clear beet sugar juice; the beet sugar juice is treated by a nanofiltration membrane 15 to remove partial water molecules, monosaccharides and small molecular non-sugar impurities, the rejection rate of disaccharides reaches 99.5%, and the sugar juice is primarily concentrated to 24wt% of sugar degree;
(6) Concentrating and crystallizing: treating the primary concentrated sugar juice by a reverse osmosis membrane group 18 at 80 ℃ and 3.5MPa, and concentrating the sugar juice from 15wt% of sugar degree to 50wt% of sugar degree; the permeate water is purified water and can be reused in the production process; concentrating to sugar degree of 50wt% beet sugar juice, and feeding into evaporator 19 for further concentration at 95deg.C to obtain sugar degree of 70%; crystallizing, separating and drying by conventional method to obtain beet sugar product.
The foregoing disclosure is merely illustrative of the preferred embodiments of the present invention and is not intended to limit the scope of the claims herein, as equivalent changes may be made in the claims herein without departing from the scope of the invention.