CN117800833A - Energy-saving production method and device of zinc lactate - Google Patents
Energy-saving production method and device of zinc lactate Download PDFInfo
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- CN117800833A CN117800833A CN202311837378.2A CN202311837378A CN117800833A CN 117800833 A CN117800833 A CN 117800833A CN 202311837378 A CN202311837378 A CN 202311837378A CN 117800833 A CN117800833 A CN 117800833A
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- 239000011576 zinc lactate Substances 0.000 title claims abstract description 71
- 229940050168 zinc lactate Drugs 0.000 title claims abstract description 71
- CANRESZKMUPMAE-UHFFFAOYSA-L Zinc lactate Chemical compound [Zn+2].CC(O)C([O-])=O.CC(O)C([O-])=O CANRESZKMUPMAE-UHFFFAOYSA-L 0.000 title claims abstract description 67
- 235000000193 zinc lactate Nutrition 0.000 title claims abstract description 67
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 30
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims abstract description 115
- JVTAAEKCZFNVCJ-REOHCLBHSA-N L-lactic acid Chemical compound C[C@H](O)C(O)=O JVTAAEKCZFNVCJ-REOHCLBHSA-N 0.000 claims abstract description 78
- 238000006243 chemical reaction Methods 0.000 claims abstract description 65
- 239000011787 zinc oxide Substances 0.000 claims abstract description 51
- 239000000725 suspension Substances 0.000 claims abstract description 36
- 239000007788 liquid Substances 0.000 claims abstract description 33
- 239000002994 raw material Substances 0.000 claims abstract description 21
- 238000010438 heat treatment Methods 0.000 claims abstract description 15
- 238000000926 separation method Methods 0.000 claims abstract description 14
- 238000001914 filtration Methods 0.000 claims abstract description 13
- 238000001816 cooling Methods 0.000 claims abstract description 9
- 238000002156 mixing Methods 0.000 claims abstract description 8
- 239000000706 filtrate Substances 0.000 claims abstract description 4
- 239000007790 solid phase Substances 0.000 claims abstract description 3
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 claims description 39
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 26
- 239000004310 lactic acid Substances 0.000 claims description 19
- 235000014655 lactic acid Nutrition 0.000 claims description 19
- 238000003756 stirring Methods 0.000 claims description 12
- 238000001035 drying Methods 0.000 claims description 11
- 235000013305 food Nutrition 0.000 claims description 11
- 239000012452 mother liquor Substances 0.000 claims description 10
- 238000000354 decomposition reaction Methods 0.000 claims description 4
- 238000004064 recycling Methods 0.000 claims description 4
- 238000007873 sieving Methods 0.000 claims description 3
- 239000013589 supplement Substances 0.000 claims description 2
- 239000012295 chemical reaction liquid Substances 0.000 abstract description 21
- 238000000034 method Methods 0.000 abstract description 14
- 238000002425 crystallisation Methods 0.000 abstract description 9
- 230000008025 crystallization Effects 0.000 abstract description 9
- 238000005265 energy consumption Methods 0.000 abstract description 4
- 239000012535 impurity Substances 0.000 abstract description 4
- 238000010924 continuous production Methods 0.000 abstract description 2
- 230000000630 rising effect Effects 0.000 abstract 1
- 239000000243 solution Substances 0.000 description 46
- 239000000047 product Substances 0.000 description 21
- 239000013078 crystal Substances 0.000 description 13
- 239000000843 powder Substances 0.000 description 9
- RNWHGQJWIACOKP-UHFFFAOYSA-N zinc;oxygen(2-) Chemical compound [O-2].[Zn+2] RNWHGQJWIACOKP-UHFFFAOYSA-N 0.000 description 7
- 239000002253 acid Substances 0.000 description 6
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 6
- 239000000110 cooling liquid Substances 0.000 description 6
- 238000007599 discharging Methods 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 239000011701 zinc Substances 0.000 description 6
- 239000003674 animal food additive Substances 0.000 description 5
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 4
- 239000003623 enhancer Substances 0.000 description 4
- 238000006386 neutralization reaction Methods 0.000 description 4
- 229910001220 stainless steel Inorganic materials 0.000 description 4
- 239000010935 stainless steel Substances 0.000 description 4
- 229910052725 zinc Inorganic materials 0.000 description 4
- HZUKVFGMACOUEH-UHFFFAOYSA-L zinc;2-hydroxypropanoate;dihydrate Chemical compound O.O.[Zn+2].CC(O)C([O-])=O.CC(O)C([O-])=O HZUKVFGMACOUEH-UHFFFAOYSA-L 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000000855 fermentation Methods 0.000 description 3
- 230000004151 fermentation Effects 0.000 description 3
- 235000016709 nutrition Nutrition 0.000 description 3
- 230000035764 nutrition Effects 0.000 description 3
- UOURRHZRLGCVDA-UHFFFAOYSA-D pentazinc;dicarbonate;hexahydroxide Chemical compound [OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[Zn+2].[Zn+2].[Zn+2].[Zn+2].[Zn+2].[O-]C([O-])=O.[O-]C([O-])=O UOURRHZRLGCVDA-UHFFFAOYSA-D 0.000 description 3
- 238000005406 washing Methods 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 235000015872 dietary supplement Nutrition 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 235000013336 milk Nutrition 0.000 description 2
- 239000008267 milk Substances 0.000 description 2
- 210000004080 milk Anatomy 0.000 description 2
- 239000000376 reactant Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000001502 supplementing effect Effects 0.000 description 2
- 239000008399 tap water Substances 0.000 description 2
- 235000020679 tap water Nutrition 0.000 description 2
- RZLVQBNCHSJZPX-UHFFFAOYSA-L zinc sulfate heptahydrate Chemical compound O.O.O.O.O.O.O.[Zn+2].[O-]S([O-])(=O)=O RZLVQBNCHSJZPX-UHFFFAOYSA-L 0.000 description 2
- KWYJWINJFMIDIE-UHFFFAOYSA-L zinc;2-hydroxypropanoate;trihydrate Chemical compound O.O.O.[Zn+2].CC(O)C([O-])=O.CC(O)C([O-])=O KWYJWINJFMIDIE-UHFFFAOYSA-L 0.000 description 2
- 229920002472 Starch Polymers 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000001580 bacterial effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- MKJXYGKVIBWPFZ-UHFFFAOYSA-L calcium lactate Chemical compound [Ca+2].CC(O)C([O-])=O.CC(O)C([O-])=O MKJXYGKVIBWPFZ-UHFFFAOYSA-L 0.000 description 1
- 239000001527 calcium lactate Substances 0.000 description 1
- 235000011086 calcium lactate Nutrition 0.000 description 1
- 229960002401 calcium lactate Drugs 0.000 description 1
- HPVJXNNKHRNBOY-UHFFFAOYSA-L calcium;2-hydroxypropanoate;pentahydrate Chemical compound O.O.O.O.O.[Ca+2].CC(O)C([O-])=O.CC(O)C([O-])=O HPVJXNNKHRNBOY-UHFFFAOYSA-L 0.000 description 1
- 235000013339 cereals Nutrition 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000012847 fine chemical Substances 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 238000007602 hot air drying Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- OVGXLJDWSLQDRT-UHFFFAOYSA-L magnesium lactate Chemical compound [Mg+2].CC(O)C([O-])=O.CC(O)C([O-])=O OVGXLJDWSLQDRT-UHFFFAOYSA-L 0.000 description 1
- 239000000626 magnesium lactate Substances 0.000 description 1
- 235000015229 magnesium lactate Nutrition 0.000 description 1
- 229960004658 magnesium lactate Drugs 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 235000015097 nutrients Nutrition 0.000 description 1
- 230000000050 nutritive effect Effects 0.000 description 1
- 230000009965 odorless effect Effects 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 235000019698 starch Nutrition 0.000 description 1
- 239000008107 starch Substances 0.000 description 1
- 238000000967 suction filtration Methods 0.000 description 1
- 238000005550 wet granulation Methods 0.000 description 1
- 150000003751 zinc Chemical class 0.000 description 1
- 229960001763 zinc sulfate Drugs 0.000 description 1
- 229910000368 zinc sulfate Inorganic materials 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
Landscapes
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention belongs to the technical field of zinc lactate, and particularly discloses an energy-saving production method and device of zinc lactate. The method comprises the following steps: s1, preparing an L-lactic acid solution with the mass concentration of more than 80%, and heating the L-lactic acid solution to 110-123 ℃; s2, preparing zinc oxide suspension, and heating to 90-100 ℃; s3, mixing the L-lactic acid solution obtained in the step S1 with the zinc oxide suspension obtained in the step S2 for reaction, wherein the temperature of the reaction solution is above 138 ℃, the pressure of the reaction solution is 0.40-0.50MPa, filtering the solution after the reaction for 25-35min, cooling and crystallizing the obtained filtrate, and performing solid-liquid separation to obtain solid phase, namely zinc lactate. The invention utilizes the characteristic that the solubility of zinc lactate is larger along with the temperature change to realize high-temperature high-content impurity filtration, and the crystallization yield is improved by 66 percent compared with the normal pressure mode. The heat reaction liquid and the raw material solution exchange heat mutually so as to meet the respective temperature rising and falling requirements, thereby saving energy consumption; the device provided can realize continuous production and improve production efficiency.
Description
Technical Field
The invention belongs to the field of fine chemical industry, relates to preparation of zinc lactate, and in particular relates to an energy-saving production method and device of zinc lactate.
Background
The commercial zinc lactate has national standard, which is divided into food nutrition enhancer zinc lactate standard (GB 1903.11-2015) and feed additive zinc lactate standard (GB/T23735-2009) according to the application field and quality requirements, and has molecular formula C 6 H 10 O 6 Zn•nH 2 O (n=2 or 3). Zinc lactate is white crystal or powder, and is odorless. Can be dissolved in water and slightly dissolved in ethanol. The crystallization water is lost at 100 ℃.
Zinc lactate is a zinc food enhancer with excellent performance and ideal effect, has important effects on the intelligence and physical development of infants and teenagers, and has better absorption effect than inorganic zinc. Is often used for producing zinc supplementing foods, nutrient oral liquid, children zinc supplementing tablets and medicinal granules. Can also be added into milk, milk powder, cereal food, etc.
The zinc lactate production reported or applied at home at present has the following types.
Fermentation method: lactic acid is prepared by fermenting starch, and then reacting with zinc salt. Concentrating, crystallizing, filtering and separating the generated zinc lactate solution, washing for a plurality of times by water, and drying to obtain a finished product.
And (3) a double decomposition method: after the calcium lactate (pentahydrate) is diluted, zinc sulfate (heptahydrate) is added, and the mixture is stirred, heated and refluxed for reaction. After the reaction is finished, filtering while the solution is hot, washing the solution with water to remove calcium sulfate precipitate, wherein the filtrate is milky semitransparent liquid, and cooling and standing the solution to separate out white crystals. Finally filtering, washing with water and drying to obtain white powder.
Neutralization method 1: under normal pressure, zinc oxide powder is added into the finished lactic acid solution, and the mixture is heated and stirred for 2 to 3 hours, and the reactant is cooled, crystallized, filtered and separated, washed with water for a plurality of times, and then dried to obtain the finished product.
Neutralization method 2: the lactic acid solution and basic zinc carbonate powder are used as raw materials, the molar ratio of ingredients is 6:1, the raw materials are mixed and reacted under the heating condition, and then deionized water is added for wet granulation and drying, so that the zinc lactate white crystal is obtained.
The production method has the following defects:
1. the fermentation method for preparing zinc lactate has long process flow and more auxiliary equipment, and the fermentation liquid contains impurities such as bacterial nutritive salt, residual sugar, mycoprotein and the like, so that a crystal product of the zinc lactate is light brown and is not easy to accord with the national standard;
2. the zinc lactate is prepared by a double decomposition method, the raw materials of calcium lactate and zinc sulfate are easy to obtain, the production process is simple, but the reaction byproduct calcium sulfate is slightly dissolved in water (about 0.2 percent), and after the double decomposition reaction solution is filtered and separated, calcium sulfate impurities are wrapped in the cooled and crystallized zinc lactate product, so that the zinc lactate is not suitable for being applied to foods;
3. the neutralization method 1 is used for preparing zinc lactate, the raw materials of the zinc lactate and the zinc oxide are easy to obtain, and the product quality is easy to control. However, the solubility of zinc lactate at 95 ℃ under normal pressure is only about 23.5%, and the zinc lactate is cooled and crystallized after heating reaction, so that the production efficiency of each batch is not high.
4. The neutralization method 2 is used for preparing zinc lactate, and although energy is saved, firstly, reactants cannot be filtered, acid insoluble matters brought by basic zinc carbonate raw materials cannot be removed, and the product quality is affected. Secondly, the price of the raw material basic zinc carbonate is higher, so that the product assembly is also high.
Disclosure of Invention
The invention provides an energy-saving production method and device of zinc lactate, which can improve the production efficiency and reduce the energy consumption cost while guaranteeing the quality of zinc lactate products.
In order to achieve the above object, the present invention adopts the following technical scheme: an energy-saving production method of zinc lactate comprises the following steps:
s1, preparing an L-lactic acid solution with the mass concentration of 80.0-100.0%, and heating the L-lactic acid solution to 110-123 ℃;
s2, preparing zinc oxide suspension, wherein the mass concentration of the zinc oxide suspension is 15.8-17.3%, and heating the zinc oxide suspension to 90-100 ℃;
s3, mixing the L-lactic acid solution obtained in the step S1 with the zinc oxide suspension obtained in the step S2 for reaction, wherein the temperature of the reaction solution is above 138 ℃, the pressure of the reaction solution is 0.40-0.50MPa, filtering the solution after the reaction for 25-35min, cooling and crystallizing the obtained filtrate, and performing solid-liquid separation to obtain solid phase, namely zinc lactate.
Further, the raw material for preparing the L-lactic acid solution is heat-resistant grade L-lactic acid; when the zinc oxide suspension is prepared, zinc oxide is food grade; the water is pure water, and the conductivity is less than 100 mu S/cm.
Further, in the initial reaction, zinc oxide suspension is prepared by adding water into zinc oxide powder; and (3) recycling the mother liquor after solid-liquid separation in the later stage S3 to the S2 for preparing zinc oxide suspension, and adding water to supplement when the mother liquor is insufficient.
Further, the zinc oxide slurry concentration is adjusted, and the proportioning is calculated according to the zinc lactate mass concentration of 34.0-35.0g/100g after the zinc oxide slurry concentration and lactic acid are completely double decomposed.
Further, when the L-lactic acid solution in the S3 is mixed with the zinc oxide suspension for reaction, the molar ratio of the L-lactic acid to the zinc oxide is controlled to be 2:1.
Further, S3 controls the pH of the reaction solution to be 4.0-4.5 by adjusting the feeding speed of the L-lactic acid solution; the filtering precision is 150-300 meshes; the drying temperature is 50-70 ℃.
The invention also relates to an energy-saving production device of zinc lactate, which comprises a reaction kettle, wherein a channel of the reaction kettle is of a U-shaped design, an inlet of the L-lactic acid solution and zinc oxide suspension is positioned at one end of the U-shaped channel, the other end of the U-shaped channel is a discharge hole, and both ends of the U-shaped channel are provided with stirring structures.
Further, the stirring structures at the two ends of the U-shaped channel are driven by the same driving device respectively, and the stirring directions of the stirring structures are opposite.
The control basis of the continuous feeding speed of the raw material L-lactic acid liquid and zinc oxide emulsion liquid is that the total continuous input feeding amount of 25-35 minutes is equivalent to the total capacity of the U-shaped reactor. And (3) discharging at a constant speed by discharging at a pressure of 0.40MPa (regulated by a back pressure valve) at a discharge port of the U-shaped channel of the reaction kettle. The pressure of the L-lactic acid solution in S1 is more than or equal to 0.40MPa, and the pressure of the zinc oxide suspension in S2 is more than or equal to 0.40MPa.
Further, the device also comprises an L-lactic acid solution preparing tank and a zinc oxide turbid liquid preparing tank, wherein a discharge port of the L-lactic acid solution preparing tank is connected to an L-lactic acid solution adding port of the reaction kettle after passing through the first heat exchanger, a discharge port of the zinc oxide turbid liquid preparing tank is connected to a zinc oxide turbid liquid adding port of the reaction kettle after passing through the second heat exchanger, and a discharge port of the reaction kettle is sequentially connected to a solid-liquid separation device after passing through a filtering device, a heat exchange medium channel of the first heat exchanger, a heat exchange medium channel of the second heat exchanger and a circulating water cooler, and a dryer is further arranged behind the solid-liquid separation device.
Further, the solid-liquid separation equipment is a horizontal spiral centrifuge (continuous type); the dryer is a drum dryer (continuous type), and is also connected with a crusher and a sieving machine.
The invention has the following beneficial effects:
according to the characteristics of large difference of solubility of zinc lactate aqueous solution at different temperatures, immediate crystallization after cooling, no adhesion and the like, during the reaction of lactic acid and zinc oxide, the temperature of the reaction solution is maintained at a higher stage (more than 138 ℃) by utilizing reaction heat to obtain zinc lactate solution with high content (35 g/100 g), acid insoluble impurities are filtered out at high temperature, and then cooling crystallization is carried out to prepare zinc lactate products. The invention utilizes the technological requirements that raw materials are heated and reaction liquid is cooled, the reacted solution exchanges heat with raw material lactic acid solution and zinc oxide suspension, energy consumption is saved, the heated lactic acid solution and zinc oxide have reaction exotherm in the reaction process, the purposes of heating raw material lactic acid and zinc oxide slurry mixing emulsion and cooling and crystallizing the zinc lactate clarified hot solution are achieved under the assistance of the reaction exotherm, and under the condition that a reaction liquid heating and concentrating link is not needed, about 30g/100g of finished product of reaction liquid quality can be obtained in each cycle, the production efficiency is improved by 66% compared with the normal pressure (95 ℃) production mode (18 g/100g of reaction liquid quality), and compared with 95 ℃ reaction, the energy consumption is saved by 120 ten thousand cards per ton of product.
The invention also provides an energy-saving production device of zinc lactate, which is provided with the reaction kettle with the U-shaped channel, and can realize continuous process, improve efficiency and save cost through controlling reaction conditions.
The process scheme of the invention can also be applied to the production of magnesium lactate, in particular to replacing zinc oxide with magnesium oxide, and the reaction temperature and pressure are unchanged.
Drawings
Fig. 1 is a process flow diagram of the present invention.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only for illustrating the present invention and should not be construed as limiting the scope of the present invention.
Example 1 (pilot plant test example)
33.0mol (2973.3 g) of heat-resistant L-lactic acid solution with the mass fraction of 99.70g/100g is taken and placed into a 5000ml stainless steel middle pressure tank A, a jacket oil bath is heated to 118 ℃, compressed air is introduced into a tank cavity, and the pressure is maintained at 0.6MPa;
15.0mol (1221.3 g) of food-grade zinc oxide powder with the mass fraction of 99.95g/100g is taken and placed into a 10000ml stainless steel medium-pressure tank B, a jacket oil bath with 366.6mol (6600 g) of pure water is added to heat to 95 ℃, compressed air is introduced into a tank cavity, and the pressure is maintained at 0.60MPa;
adding 400ml of lactic acid and zinc oxide emulsion (prepared from fresh pure water) in a volume ratio of 1:3.12 in a U-shaped reactor with total volume of 450ml, and adding 3ml of lactic acid to the pH value of the reaction solution to be 4.3 in the reaction process; after 27 minutes of reaction, the reaction mixture was heated by jacket circulation oil bath to raise the temperature to 138-146 ℃ and maintained at all times. Pressing zinc oxide emulsion into the U-shaped reactor at a constant speed of 11.36ml/min, and simultaneously setting the pH value of the reaction liquid measured by an online pH meter of the U-shaped reactor to be 4.0-4.5 so that the feeding speed of lactic acid pressure is about 3.64 ml/min. The discharge valve of the discharge port of the U-shaped reactor is an automatic control back pressure valve, the discharge opening pressure is set to be 0.40MPa, the self-tuning is carried out through the back pressure valve, and the discharge speed is equal to the feed speed. The discharged reaction solution was filtered by a tube filter (250 mesh) to remove acid insoluble matters. After the zinc oxide emulsion is completely input, the feeding and discharging valves are closed, and after the reaction is continued for 30 minutes, the reaction liquid is discharged from the bottom valve of the U-shaped reactor.
The reaction solution is cooled by a serpentine heat exchanger and is collected in a stainless steel barrel, 10492g of reaction solution is obtained, the temperature is 63 ℃, and then the temperature is naturally reduced to 23 ℃. After vacuum suction filtration in a buchner funnel, 4341g of zinc lactate crystal powder (a mixture of zinc lactate dihydrate and zinc lactate trihydrate) was obtained, samples were taken and tested according to the feed additive zinc lactate standard (GB/T23735-2009), and the test results are shown in Table 2. After the filtered product was dried in a blast oven at 60℃for 45 minutes, 4185g of the product (mainly zinc lactate dihydrate) was obtained, and samples were taken and tested according to the food nutrition enhancer zinc lactate standard (GB 1903.11-2015), the test results being shown in Table 3.
Example 2 (scale production):
heat-resistant grade lactic acid solution with the mass fraction of 99.60g/100g is subjected to heat exchange with hot zinc lactate reaction solution to raise the temperature, and then is continuously heated to 118-123 ℃, and is input into a U-shaped reactor by a single screw pump;
mixing zinc lactate crystallization mother liquor and zinc oxide powder to obtain suspension, wherein the mass ratio of the suspension is 5.59:1.00, and the components of the suspension are 4.83g/100g of zinc lactate, 15.17g/100g of zinc oxide and 80.0g/100g of pure water. After heat exchange and temperature rise with the hot reaction liquid, the mixture is heated to 90-95 ℃ and is input into a U-shaped reactor by a single screw pump;
in the initial stage, after the reactor is preheated by steam, in a U-shaped reactor with the volume of 1000 liters, according to the proportion of lactic acid to zinc oxide suspension (prepared by recycling mother liquor) of which the volume ratio is 1:3.23, 1000 liters are added in a metering state for chemical reaction, after a small amount of heating reaction is carried out for 25 minutes, the temperature of the reaction liquid is measured to be 144-146 ℃, the gauge pressure is 0.42-0.46MPa, and the PH value is 4.4;
continuously inputting zinc oxide suspension into the U-shaped reactor at a constant speed of 25.45L/min, and simultaneously, setting the online PH of the U-shaped reactor to be automatically controlled at the PH value of 4.0-4.5, so that the continuous feeding speed of lactic acid is 7.80-8.00L/min. And setting the opening pressure of 0.40MPa in a back pressure valve (discharge valve) of a discharge hole of the U-shaped reactor, and self-setting the continuous discharge speed. The reaction liquid with clarified high heat state is continuously input into a cluster heat exchanger after acid insoluble substances are trapped by a single bag filter connected with a discharge port;
the reaction liquid is cooled by a primary cluster heat exchanger (cooling liquid is raw material L-lactic acid) to be actually measured to be 95 ℃, cooled by a secondary cluster heat exchanger (cooling liquid is raw material zinc oxide emulsion) to be actually measured to be 51 ℃, and then cooled by a tertiary cluster heat exchanger (cooling liquid is circulating tower tap water) to be 22 ℃;
the cooled reaction liquid is continuously input into a horizontal spiral centrifuge (LW-250A) at a speed of 30-35L/min (equal to the discharging speed of the U-shaped reactor), and zinc lactate crystal powder and crystal mother liquid are continuously separated. Recovering the crystallization mother liquor to prepare zinc oxide suspension, inputting zinc lactate crystal powder into a continuous drum dryer, setting the drying time to be 30-35 minutes (the rotating speed is adjustable), and hot air drying at 55-65 ℃ to a discharge port of the dryer to collect a finished product;
after 380 minutes from the beginning of the continuous reaction, the feeding and discharging valves are closed until the whole input of the zinc oxide emulsion in the batch is completed, the reaction is continued for 30 minutes, then the machine is stopped, the reaction liquid is remained in the U-shaped reactor, and the next batch is directly used after the initial material is heated.
After the batch of products is mixed and packaged, 5443KG of zinc lactate (mainly zinc lactate dihydrate) product containing crystal water is obtained. The batch was sampled before drying and tested against the feed additive zinc lactate standard (GB/T23735-2009) and the test results are shown in Table 2. The dried product was sampled and tested according to the food nutrient supplement zinc lactate standard (GB 1903.11-2015) and the test results are shown in Table 3.
Example 3 (scale production example):
heat-resistant grade lactic acid solution with the mass fraction of 99.60g/100g is subjected to heat exchange with hot zinc lactate reaction solution to raise the temperature, and then is continuously heated to 118-123 ℃, and is input into a U-shaped reactor by a single screw pump;
mixing zinc lactate crystallization mother liquor and zinc oxide powder to obtain suspension, wherein the mass ratio of the suspension is 5.59:1.00, and the components of the suspension are 4.83g/100g of zinc lactate, 15.17g/100g of zinc oxide and 80.0g/100g of pure water. After heat exchange and temperature rise with the hot reaction liquid, the mixture is heated to 90-95 ℃ and is input into a U-shaped reactor by a single screw pump;
at the beginning of batch reaction, heating the reaction liquid in the batch on the U-shaped reactor by jacket steam until the temperature of the reaction liquid is 144-146 ℃ and the gauge pressure is 0.42-0.46MPa;
continuously inputting zinc oxide suspension into the U-shaped reactor at a constant speed of 25.45L/min, and simultaneously, setting the online PH of the U-shaped reactor to be automatically controlled at the PH value of 4.0-4.5, so that the continuous feeding speed of lactic acid is 7.80-8.00L/min. And setting the opening pressure of 0.40MPa in a back pressure valve (discharge valve) of a discharge hole of the U-shaped reactor, and self-setting the continuous discharge speed. The reaction liquid with clarified high heat state is continuously input into a cluster heat exchanger after acid insoluble substances are trapped by a single bag filter connected with a discharge port;
the reaction liquid is cooled by a primary cluster heat exchanger (cooling liquid is raw material L-lactic acid) to be actually measured to be 95-97 ℃, cooled by a secondary cluster heat exchanger (cooling liquid is raw material zinc oxide emulsion) to be actually measured to be 51-53 ℃, and cooled by a tertiary cluster heat exchanger (cooling liquid is circulating tower tap water) to be 20-22 ℃;
the cooled reaction liquid is continuously input into a horizontal spiral centrifuge (LW-250A) at a speed of 30-35L/min (equal to the discharging speed of the U-shaped reactor), and zinc lactate crystal powder and crystal mother liquid are continuously separated. And (3) recovering the crystallization mother liquor to prepare zinc oxide suspension, inputting zinc lactate crystal powder into a continuous drum dryer, drying with hot air at 55-65 ℃, and collecting the finished product at a discharge port of the dryer.
The two zinc oxide suspension slurry mixing tanks are alternately used to support continuous reaction production of each shift seamless connection operation, and the process products are subjected to continuous clear liquid filtration, heat exchange, cooling crystallization, solid-liquid separation, roller drying and batch mixing packaging to obtain the finished product of zinc lactate containing crystal water (a mixture of zinc lactate dihydrate and zinc lactate trihydrate). Batch samples were taken intermittently before drying and tested according to the feed additive zinc lactate standard (GB/T23735-2009) and the test results are shown in Table 2. The dried product was sampled intermittently and tested according to the food nutrition enhancer zinc lactate standard (GB 1903.11-2015) and the test results are shown in Table 3.
TABLE 2 detection results of zinc lactate as feed additive
TABLE 3 detection results of zinc lactate as food nutrient supplement
And (3) after the zinc lactate is repeatedly recycled at room temperature, decoloring treatment can be performed.
The invention also relates to an energy-saving production device of zinc lactate, which comprises a reaction kettle 5, wherein a reaction kettle channel is of U-shaped design, an adding port of the L-lactic acid solution and zinc oxide suspension is positioned at one end of the U-shaped channel, the other end of the U-shaped channel is a discharge port, and both ends of the U-shaped channel are provided with stirring structures. The device also comprises an L-lactic acid solution preparing tank 3 and a zinc oxide turbid liquid preparing tank 1, wherein a discharge hole of the L-lactic acid solution preparing tank 3 is connected to an L-lactic acid solution adding port of the reaction kettle after passing through a first heat exchanger 4, a discharge hole of the zinc oxide turbid liquid preparing tank 1 is connected to a zinc oxide turbid liquid adding port of the reaction kettle after passing through a second heat exchanger 2, and a discharge hole of the reaction kettle is sequentially connected to a solid-liquid separation device 8 after passing through a filtering device 6, a heat exchange medium channel of the first heat exchanger 4, a heat exchange medium channel of the second heat exchanger 3 and a circulating water cooler 7, and a dryer is further arranged behind the solid-liquid separation device. The heat exchanger can be a cluster type or a tube type heat exchanger.
Preferably, the stirring structures at two ends of the U-shaped channel are respectively driven by the same driving device, and the stirring directions of the stirring structures are opposite. The solid-liquid separation equipment is a centrifuge, preferably a horizontal spiral centrifuge; and a crusher and a sieving machine are also connected behind the dryer. The dryer is preferably a drum continuous dryer.
Wherein the inner walls of the L-lactic acid solution preparing tank, the zinc oxide suspension preparing tank and the reaction kettle are made of acid-resistant and corrosion-resistant materials, and AISI316L (American standard) stainless steel is preferred. And a heating jacket or a heating coil pipe can be arranged for heating or insulating materials.
The bottom of the U-shaped reactor and the upper part of the discharge end are provided with PH meters. The discharge hole of the zinc lactate reaction liquid is provided with a pressure control discharge valve.
The upper parts of the left and right groups of reactors of the U-shaped reactor are respectively provided with a raw material L-lactic acid feed inlet, a zinc oxide solution feed inlet and a zinc lactate reaction liquid discharge outlet. The raw material L-lactic acid feed inlet is provided with a control valve linked with a PH meter.
The specific operation principle is that raw material lactic acid (100 g/100 g) +raw material zinc oxide powder+pure water-zinc lactate solution (35 g/100 g) -zinc lactate clear liquid filtration-zinc lactate solution cooling crystallization-solid-liquid centrifugal separation-zinc lactate solid drying+zinc lactate mother liquor recycling.
The chemical reaction equation involved is: 2CH 3 CHOHCOOH+ZnO=(CH 3 CHOHCOO) 2 Zn+H 2 O
The process proportioning ratio is as follows: lactic acid (CH) 3 Chohch): zinc oxide (ZnO): water (H) 2 O) molar ratio of 2:1:24.
what is not described in detail in the present specification belongs to the known technology of those skilled in the art. The above examples describe preferred embodiments of the present invention, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.
Claims (10)
1. An energy-saving production method of zinc lactate is characterized by comprising the following steps:
s1, preparing an L-lactic acid solution with the mass concentration of 80.0-100.0%, and heating the L-lactic acid solution to 110-123 ℃;
s2, preparing zinc oxide suspension, wherein the mass concentration of the zinc oxide suspension is 15.8-17.3%, and heating the zinc oxide suspension to 90-100 ℃;
s3, mixing the L-lactic acid solution obtained in the step S1 with the zinc oxide suspension obtained in the step S2 for reaction, wherein the temperature of the reaction solution is above 138 ℃, the pressure of the reaction solution is 0.40-0.50MPa, filtering the solution after the reaction for 25-35min, cooling and crystallizing the obtained filtrate, and performing solid-liquid separation to obtain solid phase, namely zinc lactate.
2. The production method according to claim 1, characterized in that: the raw material for preparing the L-lactic acid solution is heat-resistant grade L-lactic acid; when the zinc oxide suspension is prepared, zinc oxide is food grade; the water is pure water, and the conductivity is less than 100 mu S/cm.
3. The production method according to claim 1, characterized in that: in the initial reaction, zinc oxide suspension is prepared by adding water into zinc oxide powder; and (3) recycling the mother liquor after solid-liquid separation in the later stage S3 to the S2 for preparing zinc oxide suspension, and adding water to supplement when the mother liquor is insufficient.
4. A production method according to claim 3, characterized in that: the zinc oxide slurry concentration is adjusted, and the proportioning is calculated according to the mass concentration of the zinc lactate between 34.0 and 35.0g/100g after the zinc oxide slurry concentration and the lactic acid are subjected to complete double decomposition reaction.
5. The production method according to claim 1, characterized in that: and (3) controlling the molar ratio of the L-lactic acid to the zinc oxide to be 2:1 when the L-lactic acid solution and the zinc oxide suspension are mixed for reaction in the S3.
6. The production method according to any one of claims 1 to 5, characterized in that: s3, controlling the pH value of the reaction solution to be 4.0-4.5 by adjusting the feeding speed of the L-lactic acid solution; the filtering precision is 150-300 meshes; the drying temperature is 50-70 ℃.
7. An energy-conserving apparatus for producing of zinc lactate, its characterized in that: the reaction kettle comprises a reaction kettle channel which is of a U-shaped design, wherein an adding port of an L-lactic acid solution and zinc oxide suspension is positioned at one end of the U-shaped channel, the other end of the U-shaped channel is a discharge port, and stirring structures are arranged at two ends of the U-shaped channel.
8. The energy-saving production device according to claim 7, wherein: the stirring structures at the two ends of the U-shaped channel are driven by the same driving device respectively, and the stirring directions of the stirring structures are opposite.
9. The energy-saving production device according to claim 7, wherein: the device also comprises an L-lactic acid solution preparing tank and a zinc oxide turbid liquid preparing tank, wherein a discharge port of the L-lactic acid solution preparing tank is connected to an L-lactic acid solution adding port of the reaction kettle after passing through the first heat exchanger, a discharge port of the zinc oxide turbid liquid preparing tank is connected to a zinc oxide turbid liquid adding port of the reaction kettle after passing through the second heat exchanger, and a discharge port of the reaction kettle is sequentially connected to a solid-liquid separation device after passing through filtering equipment, a heat exchange medium channel of the first heat exchanger, a heat exchange medium channel of the second heat exchanger and a circulating water cooler, and is also provided with a dryer.
10. The energy-saving production device according to claim 9, characterized in that: the solid-liquid separation equipment is a centrifuge; and a crusher and a sieving machine are also connected behind the dryer.
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| CN202311837378.2A CN117800833A (en) | 2023-12-28 | 2023-12-28 | Energy-saving production method and device of zinc lactate |
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