Green and energy-saving preparation method of starch sugar

Abstract

The invention belongs to the technical field of light industry and chemical engineering biotechnology, and particularly relates to a green energy-saving preparation method of starch sugar. The stepped temperature water tank is arranged, the temperature of feeding water is increased through evaporation and ion exchange waste heat, and therefore liquefied injection steam consumption is reduced. Tail gas injection, liquefied discharge, evaporation and ion exchange waste heat recovery form stepped temperature water, closed-loop circulation is formed, the water temperature is high, and zero emission of waste heat is achieved. Circulating cooling water is omitted, and power consumption of a cooling water pump and a cooling fan is saved. Meanwhile, a more energy-saving large-flux BC type ceramic membrane filtration, low-pressure evaporation and strong base anion resin ion exchange technology is adopted, so that the whole production line is more environment-friendly and energy-saving. According to the method, all waste heat generated in the starch sugar production process is effectively recycled, energy utilization is more reasonable, green and energy-saving production is achieved, and the starch sugar production cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of light industry and chemical industry biotechnology, and specifically relates to a green and energy-saving preparation method of starch sugar. Background Art

[0002] Starch syrup is a viscous solution made by liquefying, refining, evaporating and other processes of starch-containing substances such as corn starch, and can be used in beverages, beer, candy, food, etc. In the preparation process of starch sugar, it is usually necessary to go through high-temperature liquefaction, saccharification, filtration, separation, evaporation and concentration and other steps. Due to the differences in equipment and processes, the required temperature of each process is different. Therefore, in the actual production process, frequent heating and cooling operations are often required, which can easily lead to improper use of heat, resulting in heat waste and cost increase. Summary of the invention

[0003] The present invention starts from the whole process chain of starch sugar production, comprehensively analyzes the heat utilization of the whole process chain, designs a heat recovery process, sets up a stepped heat circulation system, recovers the waste heat of liquefaction, separation and evaporation, and performs comprehensive recycling, so as to make the heat utilization more sufficient and achieve zero waste heat emission.

[0004] The purpose of the first aspect of the present invention is to provide a green and energy-saving method for preparing starch sugar.

[0005] The second aspect of the present invention aims to provide an application.

[0006] In order to achieve the above-mentioned purpose of the present invention, the technical solution adopted by the present invention is:

[0007] The first aspect of the present invention provides a green and energy-saving method for preparing starch sugar, comprising the following steps: 1) setting a stepped temperature water tank: setting a feeding water tank, a first-level hot water tank, a second-level hot water tank, and a third-level hot water tank;

[0008] 2) Preparation of feed water: the feed water is divided into three parts: one part of the feed water is heat-exchanged with the discharge syrup of the secondary evaporation to increase the temperature, and the heat of the syrup is recovered; one part of the feed water is heat-exchanged with the condensed water / discharge syrup of the primary and secondary evaporation to increase the temperature, and the heat of the condensed water is recovered; one part of the feed water is heat-exchanged with the ion exchange feed to increase the temperature, and the heat of the ion exchange feed sugar solution is recovered; the three parts of the feed water after heat exchange are mixed and enter the feed water tank;

[0009] 3) Slurry preparation: the feed water obtained in step 2) is heated to 52° C. to 65° C. by heat exchange with the hot water in the secondary hot water tank, added to the slurry preparation tank for slurry preparation with corn starch, and then added to the slurry preparation tank for slurry preparation and adding medium-temperature amylase;

[0010] 4) Medium-temperature liquefaction: exchanging heat between the starch milk obtained in step 3) and the hot water in the third-stage hot water tank to raise the temperature to 55° C. to 63° C., spraying and liquefying to obtain a liquefied liquid;

[0011] 5) Recovery of waste heat from liquefaction: The liquefied liquid obtained in step 4) is set up with a two-stage waste heat recovery device; the first-stage waste heat recovery heat exchange of the liquefied liquid uses hot water from the second-stage hot water tank for heat exchange, and then enters the second-stage waste heat recovery heat exchange to be cooled to 55°C to 67°C and enters the saccharification tank, and the second-stage waste heat recovery heat exchange of the liquefied liquid uses hot water from the first-stage hot water tank for heat exchange;

[0012] 6) Saccharification: adding saccharifying enzyme to the liquefied liquid in step 5) to perform saccharification to obtain saccharified liquid;

[0013] 7) Primary evaporation and waste heat recovery: a portion of the sugar solution obtained in step 6) is heat exchanged with the primary evaporation discharge sugar solution, and the other portion is heat exchanged with the primary evaporation condensate, and then enters the primary MVR evaporator. The primary MVR evaporator condensate is heat exchanged with the primary evaporator feed and feed water in turn. After heat exchange, the condensate enters the deionized water tank A for primary and secondary ion exchange cleaning;

[0014] 8) Primary ion exchange and waste heat recovery: The continuous ion exchange column is cleaned with the deionized water A obtained in step 7), and the sugar solution obtained in step 7) is refined with a continuous ion exchange system;

[0015] 9) Secondary ion exchange and waste heat recovery: The secondary ion exchange column is cleaned with the deionized water A obtained in step 7), and the sugar solution obtained in step 8) is subjected to waste heat recovery with feed water, and the sugar solution is cooled to 37° C. to 48° C. and enters the secondary ion exchange for refining treatment;

[0016] 10) Chromatographic separation: The sugar solution obtained in step 9) is heated to 49° C. to 58° C. using the chromatographic discharge extract, and then heated to 62° C. to 73° C. using the hot water in the third-stage hot water tank, and then enters the chromatographic separation to obtain the chromatographic extract and the residual liquid. The hot water in the third-stage hot water tank is cooled by the chromatographic feed sugar solution and enters the second-stage hot water tank;

[0017] 11) Mixed bed refining and waste heat recovery: the sugar solution obtained in step 10) and the sugar solution obtained in step 9) are mixed in proportion to obtain F55 fructose-glucose solution; the mixed bed is cleaned with the deionized water B obtained in step 12), and the F55 fructose-glucose solution is cooled to 27°C to 38°C by heat exchange with feed water and enters the mixed bed for refining;

[0018] 12) Secondary evaporation and waste heat recovery: a portion of the F55 fructose solution obtained in step 11) is subjected to heat exchange with the secondary evaporation discharge sugar solution for temperature increase; another portion of the secondary evaporation feed sugar solution is subjected to heat exchange with the secondary evaporator condensate for temperature increase; the two portions of the secondary evaporation feed sugar solution are mixed at a temperature of 67°C to 78°C and then enter the secondary evaporator, the secondary evaporation condensate is subjected to waste heat recovery and then enters the deionized water tank B for mixed bed cleaning and regeneration.

[0019] Preferably, in step 1), the hot water temperature of the first-level hot water tank is 40-50°C.

[0020] Preferably, in step 1), the hot water temperature of the secondary hot water tank is 70-80°C.

[0021] Preferably, in step 1), the hot water temperature of the tertiary hot water tank is 90-99°C.

[0022] Preferably, in step 2), the temperature of the mixed feed water after the three parts of heat exchange is 35-55°C; more preferably 37-52°C; and even more preferably 40-50°C.

[0023] Preferably, in step 3), the feed water obtained in step (2) is heated to 55°C-62°C using hot water from a secondary hot water tank, and then added to a pulping tank. Corn starch is added to the pulping tank to prepare a starch milk with a concentration of 38-42 wt%. The starch milk is then added to a pulping tank. A 5% concentration of dilute alkali is added to the pulping tank to adjust the pH to 6.0-6.4, and then 1.2*10 medium-temperature amylase is added. 3 ~1.8*10 3 U / kg dry starch.

[0024] Preferably, in step 4), after the liquefaction, the slurry passes through the high-temperature spray and the maintenance tube respectively, and then enters the flash tank. The liquefied liquid is discharged from the bottom of the flash tank and enters the secondary enzyme addition tank. The sprayed high-temperature tail gas is discharged from the top of the flash tank and enters the tail gas recovery heat exchanger. The cold side inlet of the tail gas recovery heat exchanger is the cold side outlet water of the liquefied first-level waste heat recovery heat exchanger. The water is heated by the tail gas and enters the third-level hot water tank. The heat of the tail gas is completely recovered to form condensed water for workshop cleaning.

[0025] Preferably, in step 5), the hot water in the secondary hot water tank is heated by the liquefied liquid at the first stage and enters the exhaust gas recovery heat exchange, and then enters the tertiary hot water tank after being heated by the waste heat of the exhaust gas; the hot water in the primary hot water tank is heated by the liquefied liquid and enters the secondary hot water tank.

[0026] Preferably, in step 6), the pH of the saccharified liquid is adjusted to 4.5-4.8, and the equivalent of 3.5*10 glucoamylase is added. 4 ~4.4*10 4 U / kg dry starch, pullulanase 7.5*10 2~9.6*10 2 The composite saccharifying enzyme is mixed with 100 U / kg dry starch, and the saccharification time is more than 45 hours, so that the monosaccharide content reaches more than 95%.

[0027] Preferably, a filtering step is further included between step 6) and step 7);

[0028] Preferably, the filtration comprises ceramic membrane filtration.

[0029] Preferably, the ceramic membrane filtration includes heating the sugar solution after saccharification to 60-70° C. using hot water from a three-stage hot water tank, sequentially entering cyclone separation, scraper filtration and iron removal filtration for pretreatment, and then entering a ceramic membrane microfiltration unit.

[0030] Preferably, the ceramic membrane core adopts 0.5m 2 Large flux, 0.1μm high precision, BC type titanium dioxide polymer coating ceramic membrane filtration. The membrane filtration output clear liquid / retained liquid is 220-300 times, and the transmembrane pressure difference of the membrane filtration equipment is less than 2.5bar.

[0031] Preferably, in step 8), the outlet temperature of the condensed water of the first-stage evaporator is 77°C to 88°C. After heat exchange with the evaporator feed sugar solution, the first-stage evaporation condensed water is cooled to 55°C to 70°C; then heat exchange with the feed water is performed, and the first-stage evaporation condensed water is cooled to 42°C to 53°C and enters the deionized water tank A for first-stage and second-stage deionization cleaning.

[0032] An isomerization step is also included between step 8) and step 9).

[0033] Preferably, the isomerization comprises adjusting the pH of the sugar solution obtained in step 8) to 6.0-8.0, adding a catalyst and a reducing agent, and performing isomerization in an isomerization column.

[0034] Preferably, the catalyst comprises Mg 2+ , Mn 2+ 、Co 2+ At least one of .

[0035] Preferably, the reducing agent comprises sodium metabisulfite.

[0036] Preferably, the pH conditioning method comprises a strong base anionic resin.

[0037] Preferably, in step 12), the discharge temperature of the secondary evaporation syrup is 85°C to 95°C, and is cooled to 52°C to 68°C after heat exchange with the secondary evaporation feed. Subsequently, the temperature is cooled to 27°C to 38°C by feed water, and the feed water temperature is raised to 32°C to 43°C. The outlet temperature of the condensed water of the secondary evaporator is 86°C to 96°C, and is cooled to 54°C to 69°C after heat exchange with the secondary evaporation feed sugar solution, and is stored in the deionized water tank B for mixed bed cleaning after heat exchange to 27°C to 35°C by feed water, and the feed water is heated to 42°C to 53°C.

[0038] In some embodiments of the present invention, the green and energy-saving preparation method of starch sugar comprises the following steps:

[0039] 1) Set up a stepped temperature water tank: set up a feed water tank, a first-level hot water tank, a second-level hot water tank, and a third-level hot water tank respectively; the hot water in the tank comes from the production waste heat recovery, and then is used for heat exchange in starch sugar production, thus forming a closed loop. When the water tank liquid level is lower than 40%, add reverse osmosis water to the 45℃ water tank to ensure that the water source is clean and the water tank is not scaled.

[0040] Preferably, in step 1), the hot water temperature of the first-level hot water tank is 40-50°C; the hot water temperature of the second-level hot water tank is 70-80°C; the hot water temperature of the third-level hot water tank is 90-99°C.

[0041] 2) Preparation of feed water: The feed water is divided into three parts: one part of the feed water is heated by heat exchange with the discharge syrup (55℃-65℃) of the secondary evaporation to recover the heat of the syrup; one part of the feed water is heated by heat exchange with the condensed water / discharge syrup of the primary and secondary evaporation to recover the heat of the condensed water; one part of the feed water is heated by heat exchange with the ion exchange feed to recover the heat of the ion exchange feed sugar liquid. The three parts of the feed water after heat exchange are mixed and enter the feed water tank at a temperature of 40℃-50℃ for feeding.

[0042] 3) Slurry preparation: Heat the feed water obtained in step 2) to 55℃-62℃ using the hot water in the secondary hot water tank and add it to the pulping tank. Add corn starch into the pulping tank to prepare a 38-42wt% starch milk and add it to the pulping tank. Add 5% dilute alkali to the pulping tank to adjust the pH to 6.0-6.4, then add 1.2*10 medium-temperature amylase. 3 ~1.8*10 3 U / kg dry starch.

[0043] 4) Medium-temperature liquefaction: The starch milk obtained in step 3) is heated to 58°C-63°C by heat exchange with the hot water in the third-stage hot water tank, and then liquefied by constant pressure spraying at 0.4 MPa at a temperature of 110°C-114°C, and then the liquefaction reaction is continued through the maintenance pipe. The liquefied liquid enters the flash tank, and after flash evaporation, it enters the secondary enzyme addition tank, and the medium-temperature amylase 9*10 is added. 2~1.2*10 3 U / kg dry starch, then enters the laminar flow column and remains for 1.8h to 2.5h.

[0044] Preferably, in the medium-temperature liquefaction of step (4), the slurry passes through the high-temperature spray and the maintenance tube respectively and then enters the flash tank. The liquefied liquid is discharged from the bottom of the flash tank and enters the secondary enzyme addition tank, and the high-temperature exhaust gas is discharged from the top of the flash tank and enters the exhaust gas recovery heat exchanger. The cold side inlet of the exhaust gas recovery heat exchanger is the cold side outlet water of the liquefied first-level waste heat recovery heat exchanger. The water is heated by the exhaust gas and enters 95°C. The exhaust gas heat is completely recovered to form condensed water for workshop cleaning.

[0045] 5) Recovery of waste heat from liquefaction: The liquefied liquid obtained in step 4) is set up with a two-stage waste heat recovery device. The first-stage waste heat recovery heat exchange of the liquefied liquid uses hot water from the second-stage hot water tank for heat exchange, and then enters the second-stage waste heat recovery heat exchange to be cooled to 58°C-64°C and enter the saccharification tank. The second-stage waste heat recovery heat exchange of liquefaction uses hot water from the first-stage hot water tank for heat exchange.

[0046] Preferably, in step 5) the step of recovering the waste heat of the liquefied material, the hot water in the secondary hot water tank is heated by the liquefied liquid for the first time and then enters the tail gas for heat recovery, and then enters the hot water in the tertiary hot water tank after being heated by the waste heat of the tail gas. The hot water in the primary hot water tank is heated by the liquefied liquid for the second time and enters the secondary hot water tank, and the liquefied liquid is cooled to 58°C to 64°C and enters the saccharification tank.

[0047] 6) Saccharification: Adjust the pH of the saccharification solution to 4.5-4.8, add 3.5*10 glucoamylase 4 ~4.4*10 4 U / kg dry starch, pullulanase 7.5*10 2 ~9.6*10 2 The composite saccharifying enzyme is mixed with 100 U / kg dry starch, and the saccharification time is more than 45 hours, so that the monosaccharide content reaches more than 95wt%.

[0048] 7) Ceramic membrane filtration: The saccharification liquid after saccharification is heated to 65°C using hot water from a three-stage hot water tank, and then enters cyclone separation, scraper filtration and iron removal filtration for pretreatment, and then enters the ceramic membrane microfiltration unit.

[0049] Preferably, in step (7) of ceramic membrane filtration, the membrane core is a 0.5 m ceramic membrane produced by Orelis of France. 2 Large flux, 0.1μm high precision, BC type titanium dioxide polymer coating ceramic membrane filtration. The membrane filtration output clear liquid / retained liquid is 220-300 times, and the transmembrane pressure difference of the membrane filtration equipment is less than 2.5bar.

[0050] 8) Primary evaporation and waste heat recovery: a portion of the sugar solution obtained in step 7) is heat exchanged with the primary evaporation discharge sugar solution, and the other portion is heat exchanged with the primary evaporation condensate, and then enters the primary MVR evaporator. The evaporator pressure is set at 470mbar-475mbar, and the discharge density is set at 1191kg / m 3 ~1197kg / m 3 The condensed water of the first-stage MVR evaporator exchanges heat with the feed and feed water of the first-stage evaporator in turn. After the heat exchange, the condensed water enters the deionized water tank A for the first-stage and second-stage ion exchange cleaning.

[0051] Preferably, in step 8) the primary evaporation and waste heat recovery step, the outlet temperature of the condensed water of the primary evaporator is 80°C to 85°C. After heat exchange with the evaporator feed sugar solution, the primary evaporation condensed water is cooled to 58°C to 67°C. Then, heat exchange with the feed water is performed, and the primary evaporation condensed water is cooled to 45°C to 50°C and enters the deionized water tank A for primary and secondary deionization cleaning.

[0052] 9) Primary ion exchange and waste heat recovery: The continuous ion exchange column is cleaned with the deionized water A obtained in step 8). The sugar solution obtained in step 8) is cooled to below 60° C. by heat exchange with feed water and then enters the continuous ion exchange for refining.

[0053] 10) Isomerization: The sugar solution obtained in step 9) is placed in a strong base anion resin, and the pH of the sugar solution is raised to 6.1-7.8. A mixed solution of magnesium sulfate and sodium pyrosulfite is added to the sugar solution, and then the sugar solution is placed in an isomerization column for isomerization reaction to obtain F42 fructose syrup.

[0054] 11) Secondary ion exchange and waste heat recovery: The secondary ion exchange column is cleaned with the deionized water A obtained in step 8). The sugar solution obtained in step 10) is subjected to waste heat recovery with feed water, and the sugar solution is cooled to 40°C to 45°C and enters the secondary ion exchange for refining treatment.

[0055] 12) Chromatographic separation: The sugar solution obtained in step 11) is heated to 52°C to 55°C using the chromatographic discharge extract (60°C to 65°C), and then heated to 68°C using the hot water in the third-stage hot water tank, and then enters the chromatographic separation to obtain the chromatographic extract and the residual liquid. The hot water in the third-stage hot water tank is cooled by the chromatographic feed sugar solution and enters the second-stage hot water tank.

[0056] 13) Mixed bed refining and waste heat recovery: The sugar solution obtained in step 12) is mixed with the sugar solution obtained in step 11) in proportion to obtain F55 fructose glucose solution. The mixed bed is cleaned with the deionized water B obtained in step 14), and the F55 fructose glucose solution is cooled to 30°C to 35°C by heat exchange with feed water and then enters the mixed bed for refining.

[0057] 14) Secondary evaporation and waste heat recovery: a portion of the fructose-glucose solution obtained in step 13) is subjected to heat exchange with the secondary evaporation discharge sugar solution for heating; another portion of the secondary evaporation feed sugar solution is subjected to heat exchange with the secondary evaporator condensate for heating. After the two portions of the secondary evaporation feed sugar solution are mixed, the temperature is 70°C-75°C, and then they enter the secondary evaporator. The secondary evaporator pressure is set to 470mbar-475mbar, and the MVR discharge density is set at 1338kg / m 3 ~1342kg / m 3 The secondary evaporation condensate is recycled for waste heat and then enters the deionized water tank B for mixed bed cleaning and regeneration.

[0058] Preferably, in step 14) of the secondary evaporation and waste heat recovery step, the secondary evaporation syrup outlet temperature is 88°C to 92°C, and is cooled to 55°C to 65°C after heat exchange with the secondary evaporation feed. Subsequently, the feed water is cooled to 30°C to 35°C, and the feed water temperature is raised to 35°C to 40°C. The secondary evaporator condensate outlet water temperature is 89°C to 93°C, and is cooled to 57°C to 66°C after heat exchange with the secondary evaporation feed sugar solution, and is stored in the deionized water tank B for mixed bed cleaning after heat exchange with the feed water to 30°C-32°C, and the feed water is heated to 45°C to 50°C.

[0059] In the first aspect of the present invention, those skilled in the art may also adjust the number of gradient temperature water tanks (for example, reduce it to 2, or increase it to 4) to perform heat exchange in more environments and achieve better energy-saving effects.

[0060] The second aspect of the present invention provides application of the method of the first aspect of the present invention in the field of food and flavors.

[0061] The beneficial effects of the present invention are:

[0062] 1) The present invention can recover the waste heat from production in a step-by-step manner by setting a feed water tank, a first-level hot water tank (in some embodiments, 45°C hot water), a second-level hot water tank (in some embodiments, 75°C hot water), a third-level hot water tank (in some embodiments, 95°C hot water) and other gradient temperature water, thereby obtaining hot water with a variety of gradient temperatures. Compared with the single overall recovery method, the hot water temperature of the high-temperature part is higher, and the heating effect is better. At the same time, the production of low-temperature materials can be heated in a gradient manner to avoid insufficient or excessive hot water heat, more uniform heat release, and more reasonable and sufficient use of hot water.

[0063] 2) In the present invention, when hot water is insufficient, reverse osmosis water is added to the 45°C water tank, and then the 45°C water is used to absorb heat to replenish to 75°C water, and the 75°C water continues to absorb heat to replenish to 95°C water, thereby forming a closed loop to ensure that the entire water system is reverse osmosis water and avoid scaling.

[0064] 3) In liquefaction and waste heat recovery, by exchanging heat with the first-stage liquefaction discharge and the tail gas after liquefaction injection, the 75°C water is heated to 95°C water, so that the liquefaction waste heat and tail gas heat can be fully recovered, achieving zero waste heat emission for liquefaction and zero steam preparation for 95°C water.

[0065] 4) In the process of primary and secondary desorption, primary and secondary evaporation and waste heat recovery, the feed water is used to recover all the waste heat in the desorption and evaporation process, so that the feed water temperature is increased to 40℃~50℃. As the feed water temperature increases, the amount of steam required for injection decreases accordingly. Therefore, not only the waste heat in the desorption and evaporation process is recovered, but also the unit consumption of steam for injection is reduced by 3%-5%.

[0066] 5) In the process of separation and evaporation cooling, the present invention uses feed water instead of circulating cooling water to cool the separation and evaporation high-temperature sugar solution. Not only heat is recovered, the amount of cooling water is reduced by more than 40%, and the power consumption of cooling water pumps and fans is reduced by 55%-70%. Then, the amount of scale inhibitors, bactericides and other agents added to the circulating cooling water and the purchase cost are reduced, and the frequency of cleaning the cooling tower is reduced, which is more green and energy-saving.

[0067] 6) After the two-stage evaporation condensate is cooled in multiple stages, it is recycled and utilized by quality. Among them, the first-stage evaporation sugar solution has only been subjected to one centrifugation, while the second-stage evaporation condensate has been subjected to two centrifugations and one mixed bed, so the condensate formed by the second-stage evaporation is purer. The first-stage evaporation condensate is used for the first-stage and second-stage centrifugation cleaning, and the purer second-stage evaporation condensate is used for mixed bed cleaning, which not only recovers the evaporation condensate by quality, but also can better ensure the cleaning effect, thereby ensuring the quality of the sugar solution.

[0068] 7) In the liquefaction step, the starch milk is first heated to 58-63°C using the prepared 95°C hot water. The slurry temperature is high, and the steam consumption can be saved by up to about 6% during spraying. Then, the medium-temperature liquefaction technology is used, and the liquefaction temperature is reduced by more than 6°C compared with the traditional high-temperature liquefaction, and the liquefaction energy consumption can be reduced by more than 9%.

[0069] 8) In the ceramic membrane filtration, the membrane core adopts 0.5m 2 Large flux, BC type titanium dioxide polymer coated ceramic membrane filtration, so that the membrane filtration output clear liquid / retentate is 220-300 times, the membrane filtration concentration multiple is increased, the cleaning frequency is reduced by 23%-35%, and the membrane filtration power consumption is reduced by 20%-25%.

[0070] 9) In the first-stage MVR evaporation and second-stage MVR evaporation steps, the evaporator pressure is set at 470mbar-475mbar. Compared with the traditional MVR evaporator pressure of 500mbar-510mbar, the evaporator pressure in the present invention is lower, thereby reducing the evaporation temperature. The compressor only needs less electricity and steam to maintain the evaporation temperature and pressure. The evaporator can reduce the power consumption by up to 1kw.h for every ton of water evaporated.

[0071] 10) In the isomerization step, the sugar solution is introduced into a strong base anion resin, thereby increasing the pH of the sugar solution to a range of 6.1 to 7.8 through the action of the strong base resin, without adding an alkali solution for adjusting the pH, reducing the introduction of ions, thereby increasing the color value of the sugar solution, reducing the subsequent ion exchange pressure, and increasing the subsequent ion exchange sugar volume by more than 50%, while reducing the subsequent ion exchange cleaning and regeneration frequency and the amount of cleaning water and cleaning agent, thereby achieving the purpose of energy saving and consumption reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 It is a schematic diagram of the principle of the green and energy-saving preparation method of the present invention. DETAILED DESCRIPTION

[0073] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0074] The source information of the enzymes used in the following examples is described as follows:

[0075] Medium-temperature amylase: Manufacturer: Novozymes, Model: Medium-temperature amylase Ban 480L.

[0076] Compound saccharifying enzyme: Manufacturer: Mattel, Model: MchaoⅡ.

[0077] Example 1

[0078] A green and energy-saving preparation method of starch sugar comprises the following steps:

[0079] (1) Setting up a stepped temperature water tank: Set up hot water tanks with different gradient temperatures, including a feed water tank, a first-level hot water tank (45°C), a second-level hot water tank (75°C), and a third-level hot water tank (95°C). The hot water in the tank comes from the waste heat recovery of production, and then is used for heat exchange in starch sugar production, thus forming a closed loop. When the liquid level of the first-level water tank is lower than 40%, add reverse osmosis water to the first-level hot water tank (45°C) to ensure that the water source is clean and the water tank is not scaled.

[0080] (2) Preparation of feed water: The feed water is divided into three parts: one part of the feed water is used for heat exchange with the discharge syrup from the secondary evaporation to recover the heat of the syrup; one part of the feed water is used for heat exchange with the condensed water / discharge syrup from the primary and secondary evaporations to recover the heat of the condensed water; one part of the feed water is used for heat exchange with the ion exchange feed to recover the heat of the ion exchange feed sugar solution. The three parts of the feed water after heat exchange are mixed and then enter the feed water tank for feeding.

[0081] (3) Slurry preparation: The feed water obtained in step (2) is heated to 62°C using hot water (75°C) in a secondary hot water tank, and added to a slurry opening tank. Corn starch is added to the slurry opening tank to prepare a 42wt% starch milk, which is then added to a slurry preparation tank. A 5wt% dilute alkali is added to the slurry preparation tank to adjust the pH to 6.0, and then 0.3L / T of medium-temperature amylase is added.

[0082] (4) Medium-temperature liquefaction: The starch milk obtained in step (3) is heated to 63°C by heat exchange with the hot water (95°C) in the third-stage hot water tank, and then a constant-pressure liquefaction injection of 0.4Mpa is performed at a temperature of 110°C, and then the liquefaction reaction is continuously carried out through a maintenance tube. The liquefied liquid enters the flash tank, and after flash evaporation, it enters the secondary enzyme addition tank, and the medium-temperature amylase 0.15L / T starch is added, and then it enters the laminar flow column and maintained for 1.8h. The high-temperature exhaust gas is discharged from the top of the flash tank and enters the exhaust gas recovery heat exchanger. The cold side inlet of the exhaust gas recovery heat exchanger is the cold side outlet water of the liquefied first-stage waste heat recovery heat exchanger. The water is heated by the exhaust gas and enters 95°C. After the exhaust gas heat is fully recovered, condensed water is formed for workshop cleaning.

[0083] (5) Recovery of waste heat from liquefied material: The liquefied liquid obtained in step (4) is set up with a two-stage waste heat recovery device. The first-stage waste heat recovery heat exchange of the liquefied liquid uses hot water (75°C) from the second-stage hot water tank for heat exchange. After heat exchange, the hot water (75°C) from the second-stage hot water tank enters the tail gas recovery heat exchanger to continue absorbing heat. The liquefied liquid then enters the second-stage waste heat recovery system. The second-stage waste heat recovery heat exchange of the liquefied liquid uses hot water (45°C) from the first-stage hot water tank for heat exchange. After two-stage waste heat recovery, the liquefied liquid is cooled to 64°C and enters the saccharification tank.

[0084] (6) Saccharification: The liquefied liquid enters the saccharification tank, dilute acid is added to adjust the pH to 4.5, and composite saccharifying enzyme is added at a ratio of 0.25 L / t powder. Saccharification is carried out for 45 hours, and the monosaccharide content is detected to reach 95.4 wt%.

[0085] (7) Ceramic membrane filtration: After saccharification, the sugar solution is heated to 65°C using hot water (95°C) from a three-stage hot water tank, and then enters the cyclone separation, scraper filtration and iron removal filtration for pretreatment, and then enters the ceramic membrane microfiltration unit. The membrane core of the ceramic membrane microfiltration uses a 0.5m 2Large flux, 0.1μm high precision, BC type titanium dioxide polymer coating ceramic membrane filtration. The membrane filtration output clear liquid / retained liquid is 220 times, and the transmembrane pressure difference of the membrane filtration equipment is maintained at 1.4bar. The light transmittance of the membrane filtration output sugar solution is 99.2%.

[0086] (8) Primary evaporation and waste heat recovery: The sugar solution obtained in step (7) is divided into two parts. One part is heat exchanged with the sugar solution discharged from the primary evaporation, and the temperature of the sugar solution is raised to 76°C. The other part is heat exchanged with the condensed water (85°C) of the primary evaporation, and the condensed water of the primary evaporation is cooled to 67°C. After the sugar solution is heated, it is mixed with the first part of the sugar solution and enters the primary MVR evaporator. The evaporator pressure is set at 475mbar and the discharge density is set at 1195kg / m 3 After the condensed water of the first-stage MVR evaporator is cooled by the feed, it exchanges heat with the feed water. The condensed water is cooled to 50°C and enters the deionized water tank A for cleaning in the first-stage and second-stage ion exchange.

[0087] (9) Primary ion exchange and waste heat recovery: The continuous ion exchange column is cleaned with the deionized water A obtained in step (8). The sugar solution obtained in step (8) is cooled to 56° C. by heat exchange with feed water and then enters the continuous ion exchange for refining.

[0088] (10) The sugar solution obtained in step (9) is fed into a strong base anion resin, and the pH value of the sugar solution is raised to 6.1. A mixed solution of magnesium sulfate and sodium pyrosulfite is added to the sugar solution, and then the sugar solution is fed into an isomerization column for isomerization reaction to obtain F42 fructose syrup.

[0089] (11) Secondary ion exchange and waste heat recovery: The secondary ion exchange column is cleaned with the deionized water A obtained in step (8). The sugar solution obtained in step (10) is subjected to waste heat recovery with the feed water, and the sugar solution is cooled to 45° C. and enters the secondary ion exchange for refining treatment.

[0090] (12) Chromatographic separation: The sugar solution obtained in step (11) is heated to 55°C using the chromatographic discharge extract (65°C), and then heated to 68°C using the hot water (95°C) in the third-stage hot water tank, and then enters the chromatographic separation to obtain the chromatographic extract and the residual liquid. The hot water (95°C) in the third-stage hot water tank is cooled by the chromatographic feed sugar solution and enters the hot water (75°C) in the second-stage hot water tank.

[0091] (13) Mixed bed refining and waste heat recovery: The sugar solution obtained in step (12) and the sugar solution obtained in step (11) are mixed at a ratio of 1:1.7 to form F55 fructose-glucose solution. The mixed bed is cleaned with deionized water B, and the F55 fructose-glucose solution is cooled to 35°C with feed water and enters the mixed bed for refining. The feed water is heated and enters the feed water tank.

[0092] (14) Secondary evaporation and waste heat recovery: The F55 fructose solution obtained in step (13) is divided into two parts, one part is subjected to heat exchange with the secondary evaporation discharge sugar solution (92°C) for heating; the other part is subjected to heat exchange with the secondary evaporator condensate (93°C) for heating. The two parts of the secondary evaporation feed sugar solution are mixed and the temperature is raised to 75°C and enter the secondary evaporator. The secondary evaporator pressure is set to 475mbar, and the MVR discharge density is set to 1338kg / m 3 The outlet temperature of the secondary evaporation condensate is 93°C. After heat exchange with the secondary evaporation feed sugar solution, it is cooled to 66°C. Then, it is cooled to 32°C by feed water and enters the deionized water tank B for mixed bed cleaning and regeneration. The outlet temperature of the secondary evaporation syrup is 92°C. After heat exchange with the secondary evaporation feed, it is cooled to 66°C. Then, it is cooled to 32°C by feed water and enters the finished product storage tank. The temperature of this part of feed water is raised to 45°C and enters the feed water tank.

[0093] Example 2

[0094] A green and energy-saving method for preparing starch sugar comprises the following steps:

[0095] (1) Setting up a stepped temperature water tank: Set up hot water tanks with different gradient temperatures, including a feed water tank, a first-level hot water tank (45°C), a second-level hot water tank (75°C), and a third-level hot water tank (95°C). The hot water in the tank comes from the production waste heat recovery, and then is used for heat exchange in starch sugar production, thus forming a closed loop. When the liquid level of the first-level water tank is lower than 40%, add reverse osmosis water to the 45°C water tank to ensure that the water source is clean and the water tank is not scaled.

[0096] (2) Preparation of feed water: The feed water is divided into three parts: one part of the feed water is used for heat exchange with the discharge syrup from the secondary evaporation to recover the heat of the syrup; one part of the feed water is used for heat exchange with the condensed water / discharge syrup from the primary and secondary evaporations to recover the heat of the condensed water; one part of the feed water is used for heat exchange with the ion exchange feed to recover the heat of the ion exchange feed sugar solution. The three parts of the feed water after heat exchange are mixed and then enter the feed water tank for feeding.

[0097] (3) Slurry preparation: The feed water obtained in step (2) is heated to 59°C using hot water (75°C) in a secondary hot water tank, and added to a slurry opening tank. Corn starch is added to the slurry opening tank to prepare a 38wt% starch milk, which is then added to a slurry preparation tank. A 5wt% dilute alkali is added to the slurry preparation tank to adjust the pH to 6.3, and then 0.2L / T of medium-temperature amylase is added.

[0098] (4) Medium-temperature liquefaction: The starch milk obtained in step (3) is heated to 61°C by heat exchange with hot water (95°C) in the third-stage hot water tank, and then a constant-pressure liquefaction injection of 0.4Mpa is performed at a temperature of 114°C, and then the liquefaction reaction is continuously carried out through a maintenance tube. The liquefied liquid enters the flash tank, and after flash evaporation, it enters the secondary enzyme addition tank, and the medium-temperature amylase 0.2L / T starch is added, and then it enters the laminar flow column and maintained for 2.2 hours. The high-temperature exhaust gas is discharged from the top of the flash tank and enters the exhaust gas recovery heat exchanger. The cold side inlet of the exhaust gas recovery heat exchanger is the cold side outlet water of the liquefied first-stage waste heat recovery heat exchanger. The water is heated by the exhaust gas and enters the third-stage hot water tank (95°C). After the exhaust gas heat is fully recovered, condensed water is formed for workshop cleaning.

[0099] (5) Recovery of waste heat from liquefied material: The liquefied liquid obtained in step (4) is set up with a two-stage waste heat recovery device. The first-stage waste heat recovery heat exchange of the liquefied liquid uses hot water (75°C) from the second-stage hot water tank for heat exchange. After heat exchange, the hot water (75°C) from the second-stage hot water tank enters the tail gas recovery heat exchanger to continue absorbing heat. The liquefied liquid then enters the second-stage waste heat recovery system. The second-stage waste heat recovery heat exchange of the liquefied liquid uses hot water (45°C) from the first-stage hot water tank for heat exchange. After two-stage waste heat recovery, the liquefied liquid is cooled to 58°C and enters the saccharification tank.

[0100] (6) Saccharification: The liquefied liquid enters the saccharification tank, dilute acid is added to adjust the pH to 4.8, and composite saccharifying enzyme is added at a ratio of 0.28 L / t powder. Saccharification is carried out for 45 hours, and the monosaccharide content is detected to reach 95.7 wt%.

[0101] (7) Ceramic membrane filtration: After saccharification, the sugar solution is heated to 65°C using hot water (95°C) from a three-stage hot water tank, and then enters the cyclone separation, scraper filtration and iron removal filtration for pretreatment, and then enters the ceramic membrane microfiltration unit. The membrane core of the ceramic membrane microfiltration uses a 0.5m 2 Large flux, 0.1μm high precision, BC type titanium dioxide polymer coating ceramic membrane filtration. The membrane filtration output clear liquid / retained liquid is 260 times, and the transmembrane pressure difference of the membrane filtration equipment is maintained at 2.1bar. The light transmittance of the membrane filtration output is 98.9%.

[0102] (8) Primary evaporation and waste heat recovery: The sugar solution obtained in step (7) is divided into two parts. One part is heat exchanged with the discharge sugar solution of the primary evaporation, and the temperature of the sugar solution is raised to 75°C. The other part is heat exchanged with the condensed water (83°C) of the primary evaporation, and the condensed water of the primary evaporation is cooled to 64°C. After the sugar solution is heated, it is mixed with the first part of the sugar solution and enters the primary MVR evaporator. The evaporator pressure is set at 473 mbar and the discharge density is set at 1191 kg / m 3After the condensed water of the first-stage MVR evaporator is cooled by the feed, it exchanges heat with the feed water. The condensed water is cooled to 47°C and enters the deionized water tank A for cleaning in the first-stage and second-stage ion exchange.

[0103] (9) Primary ion exchange and waste heat recovery: The continuous ion exchange column is cleaned with the deionized water A obtained in step (8). The sugar solution obtained in step (8) is cooled to 58° C. by heat exchange with feed water and then enters the continuous ion exchange for refining.

[0104] (10) Isomerization: The sugar solution obtained in step (9) is placed in a strong base anionic resin, and the pH of the sugar solution is raised to 7.2. A mixed solution of magnesium sulfate and sodium metabisulfite is added to the sugar solution, and then the sugar solution is placed in an isomerization column for isomerization reaction to obtain F42 fructose syrup.

[0105] (11) Secondary ion exchange and waste heat recovery: The secondary ion exchange column is cleaned with the deionized water A obtained in step (8). The sugar solution obtained in step (10) is subjected to waste heat recovery with the feed water, and the sugar is liquefied and cooled to 41°C, and then enters the secondary ion exchange for refining treatment.

[0106] (12) Chromatographic separation: The sugar solution obtained in step (11) is heated to 54°C using the chromatographic discharge extract (64°C), and then heated to 68°C using the hot water (95°C) in the third-stage hot water tank, and then enters the chromatographic separation to obtain the chromatographic extract and the residual liquid. The hot water (95°C) in the third-stage hot water tank is cooled by the chromatographic feed sugar solution and enters the hot water (75°C) in the second-stage hot water tank.

[0107] (13) Mixed bed refining and waste heat recovery: The sugar solution obtained in step (12) and the sugar solution obtained in step (11) are mixed at a ratio of 1:1.7 to form F55 fructose-glucose solution. The mixed bed is cleaned with deionized water B, and the F55 fructose-glucose solution is cooled to 32°C with feed water and enters the mixed bed for refining. The feed water is heated and enters the feed water tank.

[0108] (14) Secondary evaporation and waste heat recovery: The F55 fructose solution obtained in step (13) is divided into two parts, one part is subjected to heat exchange with the secondary evaporation discharge sugar solution (90°C) for heating; the other part is subjected to heat exchange with the secondary evaporator condensate (91°C) for heating. The two parts of the secondary evaporation feed sugar solution are mixed and the temperature is raised to 72°C and enter the secondary evaporator. The secondary evaporator pressure is set to 472mbar, and the MVR discharge density is set to 1338kg / m 3The outlet temperature of the secondary evaporation condensate is 91°C. After heat exchange with the secondary evaporation feed sugar solution, it is cooled to 61°C. Then, it is cooled to 32°C by feed water and enters the deionized water tank B for mixed bed cleaning and regeneration. The outlet temperature of the secondary evaporation syrup is 90°C. After heat exchange with the secondary evaporation feed, it is cooled to 60°C. Then, it is cooled to 31°C by feed water and enters the finished product storage tank. The temperature of this part of feed water is raised to 47°C and enters the feed water tank.

[0109] Example 3

[0110] A green and energy-saving method for preparing starch sugar comprises the following steps:

[0111] (1) Setting up a stepped temperature water tank: Set up hot water tanks with different gradient temperatures, including a feed water tank, a first-level hot water tank (45°C), a second-level hot water tank (75°C), and a third-level hot water tank (95°C). The hot water in the tank comes from the production waste heat recovery, and then is used for heat exchange in starch sugar production, thus forming a closed loop. When the liquid level of the first-level water tank is lower than 40%, add reverse osmosis water to the 45°C water tank to ensure that the water source is clean and the water tank is not scaled.

[0112] (2) Preparation of feed water: The feed water is divided into three parts: one part of the feed water is used for heat exchange with the discharge syrup from the secondary evaporation to recover the heat of the syrup; one part of the feed water is used for heat exchange with the condensed water / discharge syrup from the primary and secondary evaporations to recover the heat of the condensed water; one part of the feed water is used for heat exchange with the ion exchange feed to recover the heat of the ion exchange feed sugar solution. The three parts of the feed water after heat exchange are mixed and then enter the feed water tank for feeding.

[0113] (3) Slurry preparation: The feed water obtained in step (2) is heated to 55°C using hot water (75°C) in a secondary hot water tank, and added to a slurry opening tank. Corn starch is added to the slurry opening tank to prepare a 41wt% starch milk, which is then added to a slurry preparation tank. A 5wt% dilute alkali is added to the slurry preparation tank to adjust the pH to 6.4, and then 0.24L / T of medium-temperature amylase is added.

[0114] (4) Medium-temperature liquefaction: The starch milk obtained in step (3) is heated to 58°C by heat exchange with hot water (95°C) in the third-stage hot water tank, and then a constant-pressure liquefaction injection of 0.4Mpa is performed at a temperature of 113°C, and then the liquefaction reaction is continuously carried out through a maintenance tube. The liquefied liquid enters the flash tank, and after flash evaporation, it enters the secondary enzyme addition tank, and the medium-temperature amylase 0.18L / T starch is added, and then it enters the laminar flow column and maintained for 2.5h. The high-temperature exhaust gas is discharged from the top of the flash tank and enters the exhaust gas recovery heat exchanger. The cold side inlet of the exhaust gas recovery heat exchanger is the cold side outlet water of the liquefied first-stage waste heat recovery heat exchanger. The water is heated by the exhaust gas and enters the third-stage hot water tank (95°C). After the exhaust gas heat is fully recovered, condensed water is formed for workshop cleaning.

[0115] (5) Recovery of waste heat from liquefied material: The liquefied liquid obtained in step (4) is set up with a two-stage waste heat recovery device. The first-stage waste heat recovery heat exchange of the liquefied liquid uses hot water (75°C) from the second-stage hot water tank for heat exchange. After heat exchange, the hot water (75°C) from the second-stage hot water tank enters the tail gas recovery heat exchanger to continue absorbing heat. The liquefied liquid then enters the second-stage waste heat recovery system. The second-stage waste heat recovery heat exchange of the liquefied liquid uses hot water (45°C) from the first-stage hot water tank for heat exchange. After two-stage waste heat recovery, the liquefied liquid is cooled to 61°C and enters the saccharification tank.

[0116] (6) Saccharification: The liquefied liquid enters the saccharification tank, dilute acid is added to adjust the pH to 4.7, and composite saccharifying enzyme is added at a ratio of 0.32 L / t powder. Saccharification is carried out for 48 hours, and the monosaccharide content is detected to reach 96.5 wt%.

[0117] (7) Ceramic membrane filtration: After saccharification, the sugar solution is heated to 65°C using hot water (95°C) from a three-stage hot water tank, and then enters the cyclone separation, scraper filtration and iron removal filtration for pretreatment, and then enters the ceramic membrane microfiltration unit. The membrane core of the ceramic membrane microfiltration uses a 0.5m 2 Large flux, 0.1μm high precision, BC type titanium dioxide polymer coating ceramic membrane filtration. The membrane filtration output clear liquid / retained liquid is 300 times, and the transmembrane pressure difference of the membrane filtration equipment is maintained at 2.5bar. The light transmittance of the membrane filtration output is 98.5%.

[0118] (8) Primary evaporation and waste heat recovery: The sugar solution obtained in step (7) is divided into two parts. One part is heat exchanged with the discharge sugar solution of the primary evaporation, and the temperature of the sugar solution is raised to 72°C. The other part is heat exchanged with the condensed water (80°C) of the primary evaporation, and the condensed water of the primary evaporation is cooled to 59°C. After the sugar solution is heated, it is mixed with the first part of the sugar solution and enters the primary MVR evaporator. The evaporator pressure is set at 470mbar and the discharge density is set at 1197kg / m 3 After the condensed water of the first-stage MVR evaporator is cooled by the feed, it exchanges heat with the feed water. The condensed water is cooled to 45°C and enters the deionized water tank A for cleaning in the first and second stages of deionization.

[0119] (9) Primary ion exchange and waste heat recovery: The continuous ion exchange column is cleaned with the deionized water A obtained in step (8). The sugar solution obtained in step (8) is cooled to 59° C. by heat exchange with feed water and then enters the continuous ion exchange for refining.

[0120] (10) Isomerization: The sugar solution obtained in step (9) is placed in a strong base anionic resin, and the pH of the sugar solution is raised to 7.8. A mixed solution of magnesium sulfate and sodium metabisulfite is added to the sugar solution, and then the sugar solution is placed in an isomerization column for isomerization reaction to obtain F42 fructose syrup.

[0121] (11) Secondary ion exchange and waste heat recovery: The secondary ion exchange column is cleaned with the deionized water A obtained in step (8). The sugar solution obtained in step (10) is subjected to waste heat recovery with the feed water, and the sugar solution is cooled to 44° C. and enters the secondary ion exchange for refining treatment.

[0122] (12) Chromatographic separation: The sugar solution obtained in step (11) is heated to 52°C using the chromatographic discharge extract (60°C), and then heated to 68°C using the hot water (95°C) in the third-stage hot water tank, and then enters the chromatographic separation to obtain the chromatographic extract and the residual liquid. The hot water (95°C) in the third-stage hot water tank is cooled by the chromatographic feed sugar solution and enters the hot water (75°C) in the second-stage hot water tank.

[0123] (13) Mixed bed refining and waste heat recovery: The sugar solution obtained in step (12) and the sugar solution obtained in step (11) are mixed at a ratio of 1:1.7 to form F55 fructose-glucose solution. The mixed bed is cleaned with deionized water B, and the F55 fructose-glucose solution is cooled to 30°C with feed water and enters the mixed bed for refining. The feed water is heated and enters the feed water tank.

[0124] (14) Secondary evaporation and waste heat recovery: The F55 fructose solution obtained in step (13) is divided into two parts, one part is subjected to heat exchange with the secondary evaporation discharge sugar solution (88°C) for heating; the other part is subjected to heat exchange with the secondary evaporator condensate (89°C) for heating. The two parts of the secondary evaporation feed sugar solution are mixed and the temperature is raised to 70°C and enter the secondary evaporator. The secondary evaporator pressure is set to 470mbar, and the MVR discharge density is set to 1342kg / m 3 The outlet temperature of the secondary evaporation condensate is 90°C. After heat exchange with the secondary evaporation feed sugar solution, it is cooled to 57°C. Then, it is cooled to 30°C by feed water and enters the deionized water tank B for mixed bed cleaning and regeneration. The outlet temperature of the secondary evaporation syrup is 88°C. After heat exchange with the secondary evaporation feed, it is cooled to 57°C. Then, it is cooled to 30°C by feed water and enters the finished product storage tank. The temperature of this part of feed water is raised to 50°C and enters the feed water tank.

[0125] Comparative Example 1

[0126] (1) Slurry preparation: directly add pure feed water into the slurry tank, add corn starch into the slurry tank, prepare a 42wt% starch milk and put it into the slurry preparation tank. Add 5% diluted alkali into the slurry preparation tank to adjust the pH value to 6.0, and then add medium temperature amylase 0.3L / T starch.

[0127] (2) High-temperature liquefaction: The starch milk obtained in step (1) was subjected to constant-pressure liquefaction spraying at 119°C and 0.4 MPa, and then the liquefaction reaction was continued through a maintenance tube. The liquefied liquid entered the flash tank, and after flash evaporation, it entered the secondary enzyme addition tank, where high-temperature amylase 0.15 L / T starch was added, and then entered the laminar flow column for 1.9 hours. After the slurry spray liquefaction was completed, the unit consumption of spray steam was 0.25 t steam / t powder.

[0128] (3) Saccharification: The liquefied liquid enters the saccharification tank, dilute acid is added to adjust the pH to 4.6, and composite saccharifying enzyme is added at a ratio of 0.25 L / t powder. Saccharification is carried out for 46 hours, and the monosaccharide content is detected to reach 95.5 wt%.

[0129] (4) Ceramic membrane filtration: After saccharification, the saccharified liquid is heated to 64°C and sequentially enters cyclone separation, scraper filtration and iron removal filtration for pretreatment, and then enters the ceramic membrane microfiltration unit. The membrane core of the ceramic membrane microfiltration adopts a 0.5m 2 Large flux, 0.1μm high precision, BC type titanium dioxide polymer coating ceramic membrane filtration. The membrane filtration output clear liquid / retained liquid is 220 times, and the transmembrane pressure difference of the membrane filtration equipment is maintained at 1.5bar. The light transmittance of the membrane filtration output sugar solution is 98.9%.

[0130] (5) Primary evaporation: The sugar solution in step (4) is heated to 77°C and then enters the primary MVR evaporator. The evaporator pressure is set at 473 mbar and the discharge density is set at 1194 kg / m 3 After the first-stage evaporation condensate is heat exchanged with the sugar solution feed, it is cooled to 43°C using circulating cooling water and enters the deionized water tank A for standby use.

[0131] (6) Primary ion exchange: The continuous ion exchange is cleaned with deionized water, and the sugar solution obtained in step (5) is cooled to 55°C by heat exchange with circulating cooling water, and then enters the continuous ion exchange for refining. The sugar solution obtained in step (6) enters the strong base anion resin, and the pH value of the sugar solution is raised to 6.2.

[0132] (7) Isomerization: A mixed solution of magnesium sulfate and sodium metabisulfite is added to the sugar solution, and the pH is adjusted to 7.5 using a dilute caustic soda solution. The sugar solution then enters the isomerization column for isomerization reaction to obtain F42 fructose syrup.

[0133] (8) Secondary ion exchange: The secondary ion exchange column is cleaned with deionized water, and the sugar solution obtained in step (7) is cooled to 43° C. with circulating cooling water and enters the secondary ion exchange for refining treatment.

[0134] (9) Chromatographic separation: The sugar solution obtained in step (8) is heated to 54°C using steam, and then heated to 68°C using 95°C water for a second time, and then subjected to chromatographic separation to obtain a chromatographic extract and a residual liquid.

[0135] (10) Mixed bed refining: The sugar solution obtained in step (9) and the sugar solution obtained in step (8) are mixed at a ratio of 1:1.7 to form F55 fructose-glucose solution. The mixed bed is cleaned with deionized water, and the F55 fructose-glucose solution is cooled to 34°C with chiller water (7°C) and then enters the mixed bed for refining.

[0136] (11) Secondary evaporation: The sugar solution obtained in step (10) is heated to 73°C with hot water / steam and then enters the secondary evaporator. The secondary evaporator pressure is set to 473 mbar and the MVR discharge density is set to 1339 kg / m 3 The syrup discharged from the evaporator is cooled to 31°C using chiller water (7°C) and enters the finished product storage tank.

[0137] Effect example

[0138] In order to better reflect the energy-saving difference between the present invention and the existing conventional production process, conventional preparation was carried out using corn starch with the same indicators as in Examples 1 to 3, and the results are as follows.

[0139] The following is a comparison of energy saving data between each embodiment and the comparative example:

[0140]

[0141] It should be noted that, in the relevant comparison process, the power of each machine equipment in the three embodiments and one comparative example is the same, and the use time is the same. For large-scale syrup production, the energy-saving effect is not caused by the difference in a certain equipment adopted by the comparative example and the embodiment, but comes from the system difference of different methods.

Claims

1. A green and energy-saving preparation method of starch sugar, comprising the following steps: 1) Set up a stepped temperature water tank: including a feed water tank, first-level, second-level, and third-level hot water tanks; 2) Preparation of feed water: The feed water is divided into three parts: heat exchange and temperature increase with the discharge syrup of the secondary evaporation, the condensed water / discharge syrup of the primary and secondary evaporation, and the ion exchange feed respectively, and the feed water after heat exchange is mixed and enters the feed water tank; 3) Slurry preparation; 4) Medium temperature liquefaction: The slurry is heated to 55°C to 63°C by heat exchange with the hot water in the third-stage hot water tank for liquefaction; 5) Recovery of waste heat from liquefied material: The liquefied liquid obtained in step 4) is placed in a two-stage waste heat recovery device for heat exchange; 6) Saccharification; 7) Primary evaporation and waste heat recovery: exchanging heat between the sugar solution obtained in step 6) and the sugar solution discharged from the primary evaporation and the condensed water from the primary evaporation to obtain condensed water A; 8) Primary and secondary ion exchange and waste heat recovery; 9) Chromatographic separation; 10) Mixed bed refining and waste heat recovery: The sugar solution obtained in step 9) is cooled to 27°C to 38°C by heat exchange with feed water and then enters the mixed bed for refining; 11) Secondary evaporation and waste heat recovery: The sugar solution obtained in step 10) is subjected to heat exchange with the secondary evaporation discharge sugar solution and the secondary evaporator condensate to raise the temperature. After mixing, the temperature is 67°C to 78°C, and the mixture enters the secondary evaporator to obtain condensate B.

2. The preparation method according to claim 1, characterized in that: In step 1), the hot water temperature of the first-level hot water tank is 40-50° C.; and / or The hot water temperature of the secondary hot water tank is 70-80°C; and / or The hot water temperature of the three-stage hot water tank is 90-99°C; Preferably, when the liquid level in the primary hot water tank is lower than 40%, reverse osmosis water is added to the primary hot water tank.

3. The preparation method according to claim 1, characterized in that: In step 2), the temperature of the three parts of feed water after heat exchange is mixed to be 35-55°C; Preferably, the slurry adjustment in step 3) includes exchanging heat between the feed water obtained in step 2) and the hot water in the secondary hot water tank to raise the temperature to 52°C to 65°C, adding the feed water to the slurry opening tank for slurrying with corn starch, and then adding the feed water to the slurry adjustment tank for slurry adjustment and adding medium-temperature amylase.

4. The method according to claim 1, characterized in that: In step 4), after the liquefaction, the slurry passes through the high-temperature spray and the maintenance tube respectively, and then enters the flash tank. The liquefied liquid is discharged from the bottom of the flash tank and enters the secondary enzyme addition tank. The sprayed high-temperature tail gas is discharged from the top of the flash tank and enters the tail gas recovery heat exchanger. The cold side inlet of the tail gas recovery heat exchanger is the cold side outlet water of the liquefied first-level waste heat recovery heat exchanger. The water is heated by the tail gas and enters the third-level hot water tank. The tail gas heat is completely recovered to form condensed water for workshop cleaning.

5. The method according to claim 1, characterized in that: In step 5), the first-level waste heat recovery heat exchange of the liquefied liquid uses hot water from the second-level hot water tank for heat exchange, and then enters the second-level waste heat recovery heat exchange to be cooled to 55°C to 67°C and enters the saccharification tank. The second-level waste heat recovery heat exchange of the liquefied liquid uses hot water from the first-level hot water tank for heat exchange; Preferably, in step 5), the hot water in the secondary hot water tank is heated by the liquefied liquid at the first stage and enters the exhaust gas recovery heat exchange, and then enters the tertiary hot water tank after being heated by the waste heat of the exhaust gas; the hot water in the primary hot water tank is heated by the liquefied liquid and enters the secondary hot water tank.

6. The method according to claim 1, characterized in that: Step 6) of saccharification includes adding saccharifying enzyme to carry out saccharification; Preferably, a filtering step is further included between step 6) and step 7); Preferably, the filtration comprises ceramic membrane filtration.

7. The method according to claim 1, characterized in that: In step 8), after the first-stage separation and refining, the obtained sugar solution is used to recover the waste heat with the feed water, and the sugar solution is cooled to 37°C to 48°C and enters the second-stage separation and refining treatment; Preferably, the outlet temperature of the first-stage evaporator condensate is 77°C to 88°C. After heat exchange with the evaporator feed sugar solution, the first-stage evaporation condensate is cooled to 55°C to 70°C. Then, it is heat exchanged with the feed water, and the first-stage evaporation condensate is cooled to 42°C to 53°C and enters the deionized water tank A for first-stage and second-stage deionization cleaning.

8. The method according to claim 1, characterized in that: In step 9), the chromatographic separation is as follows: the saccharified liquid obtained in step 8) is heated to 49°C to 58°C using the chromatographic discharge extract, and then heated to 62°C to 73°C using the hot water in the third-stage hot water tank, and then enters the chromatographic separation to obtain the chromatographic extract and the residual liquid, and the hot water in the third-stage hot water tank is cooled by the chromatographic feed sugar solution and enters the second-stage hot water tank; Preferably, an isomerization step is further included between step 8) and step 9); Preferably, the isomerization comprises adjusting the pH of the sugar solution obtained in step 8) to 6.0-8.0, adding a catalyst and a reducing agent, and performing isomerization in an isomerization column; Preferably, the catalyst comprises Mg 2+ , Mn 2+ 、Co 2+ At least one of; Preferably, the reducing agent comprises sodium metabisulfite; Preferably, the pH conditioning method comprises a strong base anionic resin.

9. The method according to claim 1, characterized in that: In step 11), the discharge temperature of the secondary evaporation syrup is 85°C to 95°C, and is cooled to 52°C to 68°C after heat exchange with the secondary evaporation feed. It is then cooled to 27°C to 38°C by feed water, and the feed water temperature is raised to 32°C to 43°C. The outlet temperature of the condensed water of the secondary evaporator is 86°C to 96°C, and is cooled to 54°C to 69°C after heat exchange with the secondary evaporation feed sugar solution, and is stored in the deionized water tank B for mixed bed cleaning after heat exchange to 27°C to 35°C by feed water, and the feed water is heated to 42°C to 53°C.

10. Use of the method according to any one of claims 1 to 9 in the fields of food, fermentation, and spices and flavors.

Images