Production process and equipment for corn steep liquor dry powder

Abstract

The invention relates to a corn steep liquor dry powder production process and equipment. The production process comprises the following steps: 1, a corn steep liquor production process: (1) raw material pretreatment, (2) soaking process, and (3) soaking liquid separation; 2, concentrating the corn steep liquor; and 3, drying the concentrated corn steep liquor. The production equipment comprises a low-temperature vacuum concentrator, an evaporation concentration system with a heat pump system and a vacuum liquid belt dryer. The corn steep liquor concentration efficiency is high, the concentration effect is good, energy consumption is low, waste gas pollution is avoided, active ingredients of the corn steep liquor are well kept, and the product quality is excellent.

Description

Technical Field

[0001] The present invention relates to the technical field of food chemistry, and specifically refers to a production process and equipment for corn steep liquor powder. Background Art

[0002] Corn Steep Liquor Powder (CSLP) is a powdered product made from the steep liquor in the corn starch production process, i.e., corn steep liquor, through processes such as filtration, concentration, drying, and packaging. It is rich in protein, amino acids, vitamins, minerals, and growth factors, and is a high-value natural fermentation nitrogen source and nutritional supplement.

[0003] The protein content of corn steep liquor powder is 40%-60% (mainly soluble protein, easy to absorb), rich in B vitamins (such as biotin, pantothenic acid, etc.), organic acids (such as lactic acid), and minerals (such as phosphorus, potassium, magnesium). It also contains natural growth factors essential for microbial growth, which can promote the metabolism of bacteria.

[0004] Corn steep liquor powder has good water solubility, fine powder, and is easily soluble in water, making it suitable for preparing liquid or solid fermentation media.

[0005] In the biological fermentation industry, as a source of nitrogen and growth factors, corn steep liquor powder can be used in the production of antibiotics such as penicillin and streptomycin; it can be used in the fermentation of amino acids such as glutamic acid and lysine; it can also be used in the cultivation of enzyme preparations such as amylase and protease.

[0006] In the food industry, corn steep liquor powder can replace part of soybean meal or bran and be used in the fermentation of seasonings such as soy sauce and vinegar to enhance umami; it can also optimize the cost of the medium and be used in the cultivation of probiotics such as yogurt and lactic acid bacteria.

[0007] In the feed industry, it can be used as a feed additive for aquatic products and livestock and poultry to supplement protein and vitamins and enhance the immunity of animals.

[0008] In other fields, it can also be used as an organic fertilizer fermentation promoter, the base of biological pesticide medium, etc.

[0009] The production process of corn steep liquor powder mainly includes steps such as raw material pretreatment, concentration, and drying, aiming to convert corn steep liquor into a powdered product that is easy to store and transport.

[0010] Existing corn steep liquor concentration uses multi-effect evaporators or thin-film evaporators, or MVR evaporation concentration, to concentrate corn steep liquor from about 50%-60% water content to 30%-40%. Using these devices, after concentrating to 30%-40% water content, the corn steep liquor cannot be further concentrated. When further concentrating, the viscosity of the material increases, the concentration efficiency is poor, and phenomena such as pipeline blockage and equipment scaling are likely to occur.

[0011] However, the existing corn steep liquor drying using spray drying has high energy consumption. It requires about 3 tons of steam to evaporate one ton of water. Converted to 1 ton of corn steep liquor dry powder, it requires approximately 2.6 - 2.8 tons / ton of corn steep liquor.

[0012] Spray drying uses hot air and generates a large amount of waste gas. The main components of the waste gas are: particulate matter, odor substances such as lactic acid and low - molecular - weight organic acids, which are volatile components, and high - temperature and high - humidity gas with a temperature usually of 80 - 120°C. The tail gas must be purified before being discharged, and the environmental protection treatment cost is high. Summary of the Invention

[0013] The technical problem to be solved by the present invention is: to solve the problems existing in the above - mentioned prior art, and to provide a production process and equipment for corn steep liquor dry powder, which has high corn steep liquor concentration efficiency, good thickening effect, low drying energy consumption, does not produce waste gas to pollute the environment, low production cost of corn steep liquor dry powder, and good product quality.

[0014] The technical solution adopted by the present invention is: A production process for corn steep liquor dry powder, including: Corn steep liquor production process (1) Raw material pretreatment Corn steep liquor, which is a by - product in the process of corn starch production, contains components such as soluble protein, amino acids, vitamins, minerals, and sugars; Pretreatment: Filter to remove suspended impurities such as fibers and particles, and adjust the pH value, usually acidic, with a pH of 4.0 - 5.0; Corn cleaning: Remove non - suspended impurities through screening, magnetic separation, and air separation processes; Preparation of sulfurous acid aqueous solution: Add 0.1% - 0.2% sulfur dioxide (SO2) to the soaking solution to generate sulfurous acid water, which inhibits microbial spoilage and promotes protein softening; (2) Soaking process Counter - current soaking: The corn kernels are soaked in sulfurous acid water at 50 - 55°C for 30 - 50 hours, adopting a multi - tank series counter - current method, where the new corn contacts the thickest soaking solution, and fresh water contacts the soaked corn; Purpose: Soften the endosperm, dissolve soluble protein, sugars, and minerals, and at the same time, lactic acid bacteria ferment to produce lactic acid, and the pH drops to 3.8 - 4.5; Key reactions: Sulfur dioxide breaks the disulfide bonds of corn protein, releasing starch granules; Lactic acid bacteria ferment to produce lactic acid, acetic acid, etc., enhancing the soaking effect; (3) Separation of soaking solution Solid - liquid separation: The soaked corn is discharged through a sieve, and the soaking solution, that is, corn steep liquor, is pumped to a storage tank; Component characteristics: Dry matter content: 5% - 10%, containing protein, amino acids, lactic acid, vitamin B group, minerals; High biological activity: containing growth factors, including pantothenic acid and biotin, and being an ideal nitrogen source for microbial fermentation; II. Corn steep liquor concentration process (1) First, concentrate the corn steep liquor to a solids content of 40% using a heat pump evaporation process; (2) Then, use a low - temperature vacuum concentrator to concentrate the corn steep liquor with a solids content of 40% to a solids content of 80 - 85%; the temperature of the low - temperature concentrator is low, controlled at 40 - 50 °C, which reduces the loss of active ingredients in the corn steep liquor, can also avoid equipment scaling and pipeline blockage, reduces the drying load of the subsequent process, and improves production capacity; III. Drying process of concentrated corn steep liquor Dry the above - mentioned concentrated corn steep liquor using a vacuum liquid belt dryer, and the drying temperature is lower than 60 °C. Low - temperature drying can well preserve the active ingredients of the corn steep liquor and has low energy consumption.

[0015] In the above technical solution, the heat pump evaporation process uses an evaporation and concentration system with a heat pump system to evaporate and concentrate the corn steep liquor. The evaporation and concentration system includes an evaporation separator for containing the corn steep liquor to be evaporated and concentrated and a heat pump system. The heat pump system includes a condenser, a compressor, an evaporator, a throttling control valve, and a condensate tank. The gas - phase output pipeline at the top of the evaporation separator is connected to the condensation input end of the condenser. The condensation output end of the condenser is connected to the condensate tank. The heat exchange output end of the condenser is connected to the input end of the compressor. The output end of the compressor is connected to the heat exchange input end of the evaporator. The heat exchange output end of the evaporator is connected to the input end of the throttling control valve. The output end of the throttling control valve is connected to the heat exchange input end of the condenser; after the concentrated liquid phase output end of the evaporation separator is heat - exchanged by the evaporator, it is circulated with the output at the bottom of the evaporation separator by a circulation pump, and the concentrated corn steep liquor at the bottom of the evaporation separator is output by a discharge pump.

[0016] In the above technical solution, the low - temperature vacuum concentrator includes a heating jacket, a heating roller, a driving motor, a jacket heat source inlet, a jacket heat source outlet, a roller heat source inlet, a roller heat source outlet, and a wet gas outlet in the concentrator cavity. The heating roller is installed in the low - temperature vacuum concentrator cavity; the heating jacket is a circular sleeve wrapped around the casing. The heating roller has a cavity for the heat source to flow through itself. The upper and lower ends of the circular sleeve of the heating jacket respectively have a jacket heat source outlet and a jacket heat source inlet. One end of the heating roller is simultaneously connected to a roller heat source inlet and a roller heat source outlet; the low - temperature vacuum concentrator also has a circulating liquid inlet, and the outlet end of the pump is also connected to the circulating liquid inlet of the low - temperature vacuum concentrator through a connecting pipeline and a circulating liquid control valve.

[0017] In the above technical solution, the vacuum liquid belt dryer includes a main dryer cylinder, a dryer condenser, a vacuum unit, a feed pump, a feed pipeline, a feed nozzle, a drying belt, a heat source, and a heating plate. The drying belt is installed in the closed main dryer cylinder. The vacuum unit evacuates the dryer condenser and the main dryer cylinder through a vacuum pipeline. The feed pump is connected to the feed nozzle through the feed pipeline. The corn syrup is pressurized by the feed pump and injected into the feed nozzle through the feed pipeline. Finally, the corn syrup is sprayed onto the running drying belt by the feed nozzle. A heating plate is installed under the drying belt, and the heat source supplies heat to the heating plate. The bottom of the tail end of the main dryer cylinder has a dry powder discharge port for corn syrup. The gas phase outlet at the top of the main dryer cylinder is connected to one end of the dryer condenser, and the other end of the dryer condenser is connected to a solvent recovery tank.

[0018] A corn syrup dry powder production device includes a low-temperature vacuum concentrator, an evaporation concentration system with a heat pump system, and a vacuum liquid belt dryer. The low-temperature vacuum concentrator includes a heating jacket, a heating roller, a driving motor, a jacket heat source inlet, a jacket heat source outlet, a roller heat source inlet, a roller heat source outlet, and a wet gas outlet in the concentrator inner cavity. The heating roller is installed in the inner cavity of the low-temperature vacuum concentrator. The heating jacket is a circular sleeve wrapped around the machine shell. The heating roller has a cavity for the heat source to flow through. The upper and lower ends of the circular sleeve of the heating jacket respectively have a jacket heat source outlet and a jacket heat source inlet. One end of the heating roller is connected to both the roller heat source inlet and the roller heat source outlet at the same time. The low-temperature vacuum concentrator also has a circulating liquid inlet, and the outlet end of the pump is also connected to the circulating liquid inlet of the low-temperature vacuum concentrator through a connecting pipeline and a circulating liquid control valve. The evaporation concentration system with a heat pump system includes an evaporation separator for containing the corn syrup to be evaporated and concentrated and a heat pump system. The heat pump system includes a condenser, a compressor, an evaporator, a throttling control valve, and a condensate tank. The gas phase output pipeline at the top of the evaporation separator is connected to the condensation input end of the condenser. The condensation output end of the condenser is connected to the condensate tank. The heat exchange output end of the condenser is connected to the input end of the compressor. The output end of the compressor is connected to the heat exchange input end of the evaporator. The heat exchange output end of the evaporator is connected to the input end of the throttling control valve. The output end of the throttling control valve is connected to the heat exchange input end of the condenser. After the concentrated liquid phase output end of the evaporation separator is heat-exchanged by the evaporator, it is circulated with the output at the bottom of the evaporation separator by a circulating pump. The concentrated corn syrup at the bottom of the evaporation separator is output by a discharge pump. The described vacuum belt dryer for liquid includes a main dryer cylinder, a dryer condenser, a vacuum unit, a feed pump, a feed pipeline, a feed nozzle, a drying belt, a heat source, and a heating plate. The drying belt is installed inside the closed main dryer cylinder. The vacuum unit evacuates the dryer condenser and the main dryer cylinder through a vacuum pipeline. The feed pump is connected to the feed nozzle through the feed pipeline. The corn syrup is pressurized by the feed pump and injected into the feed nozzle through the feed pipeline, and finally the corn syrup is sprayed onto the running drying belt by the feed nozzle. A heating plate is installed under the drying belt, and the heat source supplies heat to the heating plate. The bottom of the tail end of the main dryer cylinder has a dry powder discharge port for corn syrup. The gas phase outlet at the top of the main dryer cylinder is connected to one end of the dryer condenser, and the other end of the dryer condenser is connected to a solvent recovery tank.

[0019] The outstanding substantive features and remarkable effects of the present invention: Using the heat pump evaporation and concentration process: The latent heat of vapor condensation generated during the evaporation process is recovered and reused for the evaporation of the original corn syrup solution. The energy consumption is reduced by more than 80% compared with single-effect evaporation and by more than 60% compared with multi-effect evaporation, greatly reducing the energy consumption of the original single-effect evaporation, double-effect evaporation, or multi-effect evaporation.

[0020] The heat exchangers for corn syrup evaporation, condensation and cooling, condensate recovery and cooling with cooling water, and heating with heat source are shared, but they are two different systems and the two systems do not come into direct contact. Therefore, it will not cause pollution to the corn syrup material.

[0021] Using this type of concentrator and vacuum belt dryer for liquid: Using the concentrator of this technology, the concentration of corn syrup can be increased from about 40% to 80 - 85%, greatly reducing the later drying load. At the same time, the evaporation temperature is low, which can maintain the activity of the heat-sensitive active ingredients in the corn syrup and will not cause loss of the heat-sensitive active ingredients in the corn syrup.

[0022] Using the vacuum belt dryer for liquid of this technology, it can be dried at a low temperature to maintain the activity of the heat-sensitive active ingredients in the corn syrup. At the same time, the energy consumption required for drying is low, and only 1.1 - 1.2 tons of steam are consumed for evaporating one ton of water.

[0023] The steam consumption required for the original spray drying is high, about 3 tons of steam are consumed per ton of dry powder of corn syrup per ton of product.

[0024] After using this technology, the steam consumption of the dry powder of corn syrup is reduced to less than 1.2 tons per ton, and at the same time, the activity of the heat-sensitive active ingredients in the dry powder of corn syrup is maintained.

[0025] Operating under vacuum conditions without introducing external air greatly reduces the later waste gas treatment volume, the yield of the dry powder product of corn syrup is high, and the environmental protection treatment cost is low. Description of the Drawings

[0026] Figure 1 This is the process flow diagram of the present invention; Figure 2 This is the schematic structural diagram of the evaporation and concentration system with a heat pump system; Figure 3 This is the schematic structural diagram of the low-temperature vacuum concentrator; Figure 4 This is the schematic structural diagram of the vacuum liquid belt dryer.

[0027] Annotation of the attached drawings: 1 - Evaporation separator, 2 - Condenser, 3 - Compressor, 4 - Evaporator, 5 - Throttle control valve, 6 - Condensate tank, 7 - Circulation pump, 8 - Discharge pump, 9 - Feed pump, 10 - Low-temperature vacuum concentrator, 11 - Driving motor, 12 - Heating roller, 13 - Corn syrup inlet, 14 - Concentrated corn syrup outlet, 15 - Jacket heat source inlet, 16 - Jacket heat source outlet, 17 - Roller heat source inlet, 18 - Roller heat source outlet, 19 - Heating jacket, 20 - Gas-liquid separation chamber, 21 - Gas phase pipe, 22 - Vacuum system, 23 - Pressure gauge, 24 - Main body of the dryer, 25 - Dryer condenser, 26 - Vacuum unit, 27 - Dryer feed pump, 28 - Feed pipeline, 29 - Feed nozzle, 30 - Corn syrup dry powder discharge port, 31 - Vacuum pipeline, 32 - Heat source, 33 - Heating plate, 34 - Drying belt, 35 - Solvent recovery tank. Specific embodiments

[0028] Referring to the attached drawings, a production process of corn syrup dry powder according to the present invention includes: I. Production process of corn syrup (1) Pretreatment of raw materials Corn steep liquor, namely corn syrup: a by-product in the process of corn starch production, containing components such as soluble protein, amino acids, vitamins, minerals, and sugars.

[0029] Pretreatment: Filter to remove suspended impurities such as fibers and particles, and adjust the pH value if necessary, usually acidic, pH 4.0 - 5.0; Corn cleaning: Remove impurities such as sand and straw through processes such as screening, magnetic separation, and air separation; Preparation of sulfurous acid aqueous solution: Add 0.1% - 0.2% sulfur dioxide (i.e., SO2) to the steep liquor to generate sulfurous acid water, which inhibits microbial spoilage and promotes protein softening; (2) Steeping process Countercurrent steeping, namely the mainstream process: The corn kernels are steeped in sulfurous acid water at 50 - 55°C for 30 - 50 hours, adopting a multi-tank series countercurrent method, where fresh corn contacts the strongest steep liquor, and fresh water contacts the steeped corn; Purpose: To soften the endosperm, dissolve soluble proteins, sugars, and minerals, and at the same time, lactic acid bacteria ferment to produce lactic acid, reducing the pH to 3.8 - 4.5; Key reactions: Sulfur dioxide breaks the disulfide bonds of corn proteins, releasing starch granules; Lactic acid bacteria ferment to produce lactic acid, acetic acid, etc., enhancing the soaking effect; (3)Separation of the soaking solution Solid-liquid separation: The soaked corn is discharged through a sieve, and the soaking solution, i.e., corn steep liquor, is pumped to a storage tank; Composition characteristics: Dry matter content: 5% - 10%, containing proteins, amino acids, lactic acid, vitamin B group, minerals, etc.; High biological activity: Containing growth factors, including pantothenic acid and biotin, it is an ideal nitrogen source for microbial fermentation; II. Corn steep liquor concentration process (1)First, concentrate the corn steep liquor to a solids content of 40% using a heat pump evaporation process; (2)Then, use a low-temperature vacuum concentrator to concentrate the corn steep liquor with a solids content of 40% to a solids content of 80 - 85%; The temperature of the low-temperature concentrator is low, controlled at 40 - 50 °C, reducing the loss of active ingredients in the corn steep liquor, avoiding equipment scaling and pipeline blockage, reducing the drying load of the subsequent process, and improving production capacity; III. Drying process of concentrated corn steep liquor Dry the above-mentioned concentrated corn steep liquor using a vacuum liquid belt dryer, and the drying temperature is below 60 °C. Low-temperature drying can well preserve the active ingredients of the corn steep liquor and has low energy consumption. Examples

[0030] Concentration: Add 108 kg of corn steep liquor with a solids content of 41% to a low-temperature concentrator with a heat transfer area of 3 square meters. Under a vacuum of -0.09 MPa, a heating water temperature of 76 °C, a condenser condensate water temperature of 5 °C, and a roller speed of 25 Hz, the evaporation temperature is 50 °C.

[0031] After concentrating for 70 minutes, 54 kg of condensate water is collected, and 54 kg of the product is discharged, with a solids content of 82% in the discharge. The concentrated material is in a paste form, relatively viscous, and has poor fluidity.

[0032] Drying: Pump the concentrated material into a two-layer vacuum liquid belt dryer with a heat exchange area of 10 square meters, and control the vacuum degree of the liquid belt dryer at -0.099 MPa; the frequency of the feed pump for the first layer is controlled at 26 Hz, and the second layer is controlled at 30 Hz; control the temperature of the heat transfer oil for heating and cooling. The temperature of the incoming warm oil in the first heating zone is controlled at 110 °C, the second heating zone is controlled at 90 °C, and the third heating zone is controlled at 40 °C for the incoming cooling oil; control the running frequency of the track motor. The running frequencies of the track motors for the first and second layers are both controlled at 12 Hz. Before discharging, it is crushed by a crusher, and the aperture of the crusher screen is selected to be 2 mm.

[0033] The total running time of the material on the track is controlled at 45 min.

[0034] After drying, it is in the shape of bread and relatively brittle. It is crushed and discharged by a crusher. After testing, the moisture content of the corn steep liquor dry powder is 4.8%. Example

[0035] Concentration: Add 57.5 kg of corn steep liquor with a solid content of 40% to a low-temperature concentrator with a heat exchange area of 3 square meters. Under a vacuum degree of -0.096 MPa, a heating water temperature of 76 °C, a condenser condensate water temperature of 5 °C, and a roller speed of 25 Hz, with an evaporation temperature of 40 °C, after concentrating for 40 min, 29.5 kg of condensate water is collected, and 28 kg of discharged material with a solid content of 82% is obtained. The concentrated material is in a paste state, relatively viscous, and has poor fluidity.

[0036] Drying: Pump the concentrated material into a two-layer vacuum liquid belt dryer with a heat exchange area of 10 square meters, and control the vacuum degree of the liquid belt dryer at -0.099 MPa; the first layer of the feed pump does not feed, and the second layer is controlled at 50 Hz; control the temperature of the heat transfer oil for heating and cooling. The temperature of the incoming warm oil in the first heating zone is controlled at 120 °C, the second heating zone is controlled at 120 °C, and the third heating zone is controlled at 80 °C for the incoming oil temperature; the fourth cooling zone is controlled at 40 °C for the incoming oil temperature. Control the running frequency of the track motor. The running frequency of the track motor for the second layer is controlled at 36 Hz. Before discharging, it is crushed by a crusher, and the aperture of the crusher screen is selected to be 2 mm.

[0037] The total running time of the material on the track is controlled at 22 min.

[0038] During the cloth-making process, the foaming is stable. The product is in the shape of a cake and relatively brittle. It is crushed and discharged by a crusher. After testing, the moisture content of the corn steep liquor dry powder is 5.6%. Example

[0039] Concentration: 94 kg of corn syrup with a solids content of 40% was added to a low-temperature concentrator with a heat exchange area of 3 square meters. At a vacuum of -0.093 MPa, a heating water temperature of 76 °C, a condenser condensate temperature of 5 °C, and a roller speed of 20 Hz, the evaporation temperature was 44 °C. After 45 minutes of concentration, 44.5 kg of condensate was collected, and 49.5 kg of the product was discharged, with a solids content of 76% in the discharged material. The concentrated material was in a paste form, relatively viscous, and had poor fluidity. When the temperature of the concentrated material was below 30 °C, its fluidity was very poor and its adhesion was relatively strong.

[0040] Drying: The concentrated material was pumped into a two-layer vacuum liquid belt dryer with a heat exchange area of 10 square meters, and the vacuum of the liquid belt dryer was controlled at -0.099 MPa; the feed pump frequency was controlled at 15 Hz for the first layer and 18 Hz for the second layer; the temperature of the heat transfer oil for heating and cooling was controlled. The temperature of the incoming warm oil was controlled at 100 °C in the first heating zone, 100 °C in the second heating zone, 70 °C in the third heating zone, and 24 °C in the fourth cooling zone; the running frequency of the track motor was controlled. The running frequencies of the track motors for the first and second layers were both controlled at 16 Hz. Before discharging, it was crushed by a crusher, and the aperture of the crusher screen was selected to be 0.8 mm.

[0041] The total running time of the material on the track was controlled at 45 minutes.

[0042] The product was in a bread-like shape and relatively brittle. After testing, the moisture content of the corn syrup dry powder was 4.0%.

[0043] See Figure 2 , the heat pump evaporation process uses an evaporation and concentration system with a heat pump system to evaporate and concentrate corn syrup. The evaporation and concentration system includes an evaporation separator for containing the corn syrup to be evaporated and concentrated and a heat pump system. The heat pump system includes a condenser, a compressor, an evaporator, a throttle control valve, and a condensate tank. The gas-phase output pipeline at the top of the evaporation separator is connected to the condensate input end of the condenser, the condensate output end of the condenser is connected to the condensate tank, the heat exchange output end of the condenser is connected to the input end of the compressor, the output end of the compressor is connected to the heat exchange input end of the evaporator, the heat exchange output end of the evaporator is connected to the input end of the throttle control valve, and the output end of the throttle control valve is connected to the heat exchange input end of the condenser; after the concentrated liquid phase output end of the evaporation separator is heat-exchanged by the evaporator, it is circulated by a circulation pump with the output at the bottom of the evaporation separator, and the concentrated corn syrup at the bottom of the evaporation separator is output by a discharge pump.

[0044] See Figures 2 - 4 , the corn syrup dry powder production equipment includes a low-temperature vacuum concentrator, an evaporation and concentration system with a heat pump system, and a vacuum liquid belt dryer; Figure 3The low-temperature vacuum concentrator shown includes a heating jacket, a heating roller, a driving motor, a heat source inlet of the jacket, a heat source outlet of the jacket, a heat source inlet of the roller, a heat source outlet of the roller, and a wet gas outlet of the concentrator inner cavity. The heating roller is installed in the inner cavity of the low-temperature vacuum concentrator. The heating jacket is a circular sleeve wrapped around the machine shell. The heating roller has a cavity for the heat source to flow through. The upper and lower ends of the circular sleeve of the heating jacket respectively have a heat source outlet and a heat source inlet of the jacket. One end of the heating roller is connected to both the heat source inlet and the heat source outlet of the roller. The low-temperature vacuum concentrator also has a circulating liquid inlet, and the outlet end of the pump is also connected to the circulating liquid inlet of the low-temperature vacuum concentrator through a connecting pipe and a circulating liquid control valve.

[0045] Figure 2 The evaporation concentration system with a heat pump system shown includes an evaporation separator for containing corn syrup to be evaporated and concentrated and a heat pump system. The heat pump system includes a condenser, a compressor, an evaporator, a throttling control valve, and a condensate tank. The gas-phase output pipe at the top of the evaporation separator is connected to the condensation input end of the condenser. The condensation output end of the condenser is connected to the condensate tank. The heat exchange output end of the condenser is connected to the input end of the compressor. The output end of the compressor is connected to the heat exchange input end of the evaporator. The heat exchange output end of the evaporator is connected to the input end of the throttling control valve. The output end of the throttling control valve is connected to the heat exchange input end of the condenser. After the concentrated liquid phase output end of the evaporation separator is heat-exchanged by the evaporator, it is circulated through a circulating pump and the bottom output of the evaporation separator. The concentrated corn syrup at the bottom of the evaporation separator is output by a discharging pump.

[0046] Figure 4 The vacuum belt dryer for liquids shown includes a main dryer cylinder, a dryer, a dryer condenser, a vacuum unit, a feed pump, a feed pipe, a feed nozzle, a drying belt, a heat source, and a heating plate. The drying belt is installed in the closed main dryer cylinder. The vacuum unit evacuates the dryer condenser and the main dryer cylinder through a vacuum pipe. The feed pump is connected to the feed nozzle through the feed pipe. The corn syrup is pressurized by the feed pump and injected into the feed nozzle through the feed pipe, and finally the corn syrup is sprayed onto the running drying belt by the feed nozzle. A plate is installed under the drying belt, and the heat source supplies heat to the heating plate. The bottom of the tail end of the main dryer cylinder has a dry powder discharging opening for corn syrup. The gas-phase outlet at the top of the main dryer cylinder is connected to one end of the condenser, and the other end of the condenser is connected to a solvent recovery tank.

Claims

1. A corn steep liquor dry powder production process, characterized in that: include:

1. Corn Stew Production Process (1) Raw material pretreatment Corn steep liquor is a byproduct of corn starch production, containing soluble protein, amino acids, vitamins, minerals and sugars. Pretreatment: Filter to remove suspended impurities and adjust the pH value to acidic, usually pH 4.0-5.0; Corn cleaning: remove non-suspended impurities through screening, magnetic separation, and air separation processes; Preparation of sulfurous acid aqueous solution: Add 0.1%-0.2% sulfur dioxide SO2 to the soaking solution to generate sulfurous acid water, which inhibits microbial corruption and promotes protein softening; (2) Soaking process Countercurrent Soaking: Corn kernels are soaked in 50-55°C sulfite water for 30-50 hours, using a multi-tank series countercurrent method, with new corn in contact with the most concentrated soaking liquid and fresh water in contact with the soaked corn; Purpose: To soften the endosperm, dissolve soluble proteins, sugars, and minerals, and at the same time, lactic acid bacteria ferment to produce lactic acid, and the pH drops to 3.8-4.5; Key reactions: Sulfur dioxide breaks the disulfide bonds of zein, releasing starch granules; Lactic acid bacteria ferment to produce lactic acid, acetic acid, etc., which enhances the soaking effect; (3) Soaking liquid separation Solid-liquid separation: The soaked corn is discharged through the screen, and the soaking liquid, i.e. corn syrup, is pumped to the storage tank; Ingredients Features: Dry matter content: 5%-10%, containing protein, amino acids, lactic acid, B vitamins, minerals, etc.; High biological activity: Contains growth factors, including pantothenic acid and biotin, and is an ideal nitrogen source for microbial fermentation; 2. Corn Stew Concentration Process (1) First, the corn syrup is concentrated to a solid content of 40% using a heat pump evaporation process; (2) The corn syrup with a solid content of 40% is then concentrated to a solid content of 80-85% using a low-temperature vacuum concentrator; the temperature of the low-temperature concentrator is low, controlled at 40-50°C, which reduces the loss of active ingredients in the corn syrup, avoids equipment scaling and pipeline blockage, reduces the drying load of the subsequent process, and increases production capacity; Concentrated corn syrup drying process The concentrated corn syrup is dried using a vacuum liquid belt dryer at a drying temperature lower than 60° C. Low-temperature drying can well preserve the active ingredients of the corn syrup with low energy consumption.

2. A corn steep liquor dry powder production process according to claim 1, characterized in that: The heat pump evaporation process adopts an evaporation concentration system with a heat pump system to evaporate and concentrate corn slurry. The evaporation concentration system includes an evaporation separator equipped with corn slurry to be evaporated and concentrated and a heat pump system. The heat pump system includes a condenser, a compressor, an evaporator, a throttling control valve, and a condensate tank. The vapor phase output pipeline at the top of the evaporation separator is connected to the condensation input end of the condenser, the condensation output end of the condenser is connected to the condensate tank, the heat exchange output end of the condenser is connected to the compressor input end, the compressor output end is connected to the heat exchange input end of the evaporator, the heat exchange output end of the evaporator is connected to the input end of the throttling control valve, and the output end of the throttling control valve is connected to the heat exchange input end of the condenser; the concentrated liquid phase output end of the evaporation separator is circulated by a circulation pump and the bottom output of the evaporation separator after heat exchange by the evaporator, and the concentrated corn slurry at the bottom of the evaporation separator is output by a discharging pump.

3. A corn steep liquor dry powder production process according to claim 1, characterized in that: The low-temperature vacuum concentrator includes a heating shell, a heating roller, a driving motor, a shell heat source inlet, a shell heat source outlet, a roller heat source inlet, a roller heat source outlet, and a humid gas outlet for the inner cavity of the concentrator. The heating roller is installed in the inner cavity of the low-temperature vacuum concentrator; the heating shell is a circular sleeve wrapped on the shell, and the heating roller is a roller itself with a cavity for the heat source to flow. The upper and lower ends of the circular sleeve of the heating shell are respectively provided with a shell heat source outlet and a shell heat source inlet, and one end of the heating roller is connected to the roller heat source inlet and the roller heat source outlet at the same time; the low-temperature vacuum concentrator also has a circulating liquid inlet, and the outlet end of the pump is also connected to the circulating liquid inlet of the low-temperature vacuum concentrator through a connecting pipe and a circulating liquid control valve.

4. The corn steep liquor dry powder production process according to claim 1, characterized in that: The vacuum liquid belt dryer comprises a dryer main cylinder, a dryer condenser, a vacuum unit, a feed pump, a feed pipe, a feed nozzle, a drying belt, a heat source, and a heating plate. The drying belt is installed in the closed dryer main cylinder. The vacuum unit evacuates the dryer condenser and the dryer main cylinder through the vacuum pipe. The feed pump is connected to the feed nozzle through the feed pipe. The corn slurry is pressurized by the feed pump and injected into the feed nozzle through the feed pipe. Finally, the corn slurry is sprayed onto the running drying belt through the feed nozzle. A heating plate is installed under the drying belt. The heat source supplies heat to the heating plate. A corn slurry dry powder discharge port is provided at the bottom of the tail end of the dryer main cylinder. The gas phase outlet at the top of the dryer main cylinder is connected to one end of the dryer condenser, and the other end of the dryer condenser is connected to the solvent recovery tank.

5. A corn syrup dry powder production equipment, characterized in that: It includes a low-temperature vacuum concentrator, an evaporation concentration system with a heat pump system, and a vacuum liquid belt dryer; the low-temperature vacuum concentrator includes a heating shell, a heating roller, a driving motor, a shell heat source inlet, a shell heat source outlet, a roller heat source inlet, a roller heat source outlet, and a concentrator inner cavity humid gas outlet, and the heating roller is installed in the inner cavity of the low-temperature vacuum concentrator; the heating shell is a circular sleeve wrapped on the shell, the heating roller is a roller itself with a cavity for heat source circulation, and the upper and lower ends of the circular sleeve of the heating shell are respectively provided with a shell heat source outlet and a shell The heat source inlet, one end of the heating roller is connected to the roller heat source inlet and the roller heat source outlet at the same time; the low-temperature vacuum concentrator also has a circulating liquid inlet, and the outlet end of the pump is also connected to the circulating liquid inlet of the low-temperature vacuum concentrator through a connecting pipe and a circulating liquid control valve; the evaporation and concentration system with a heat pump system includes the evaporation and concentration system including an evaporation separator equipped with corn slurry to be evaporated and concentrated and a heat pump system, the heat pump system includes a condenser, a compressor, an evaporator, a throttling control valve, and a condensate tank, the vapor phase output pipeline at the top of the evaporation separator is connected to the condensation input end of the condenser, and the condensation output of the condenser is connected to the condensation input end of the condenser. The end is connected to the condensate tank, the heat exchange output end of the condenser is connected to the compressor input end, the compressor output end is connected to the heat exchange input end of the evaporator, the heat exchange output end of the evaporator is connected to the input end of the throttling control valve, and the output end of the throttling control valve is connected to the heat exchange input end of the condenser; the concentrated liquid phase output end of the evaporation separator is circulated by the circulation pump and the bottom output of the evaporation separator after heat exchange by the evaporator, and the concentrated corn slurry at the bottom of the evaporation separator is output by the discharge pump; the vacuum liquid belt dryer includes a dryer main cylinder, a dryer condenser, a vacuum unit, a feed pump, a feed pipeline, a feed nozzle, a drying belt , heat source, heating plate, the drying belt is installed in the closed main cylinder of the dryer, the vacuum unit evacuates the dryer condenser and the main cylinder of the dryer through the vacuum pipe, the feed pump is connected to the feed nozzle through the feed pipe, the corn slurry is pressurized by the feed pump and injected into the feed nozzle through the feed pipe, and finally the corn slurry is sprayed onto the running drying belt by the feed nozzle. A heating plate is installed under the drying belt, and the heat source supplies heat to the heating plate. There is a corn slurry dry powder discharge port at the bottom of the rear end of the main cylinder of the dryer, the gas phase outlet at the top of the main cylinder of the dryer is connected to one end of the dryer condenser, and the other end of the dryer condenser is connected to the solvent recovery tank.

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