CN116076557A - Constant-temperature immersion green ultralow-temperature freezing method for non-freezing liquid secondary refrigerant coupled with dry ice - Google Patents
Constant-temperature immersion green ultralow-temperature freezing method for non-freezing liquid secondary refrigerant coupled with dry ice Download PDFInfo
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- A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
- A23B4/00—General methods for preserving meat, sausages, fish or fish products
- A23B4/06—Freezing; Subsequent thawing; Cooling
- A23B4/08—Freezing; Subsequent thawing; Cooling with addition of chemicals or treatment with chemicals before or during cooling, e.g. in the form of an ice coating or frozen block
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Abstract
The invention discloses a constant-temperature dipping green ultralow-temperature freezing method of a non-freezing liquid secondary refrigerant coupling dry ice, which utilizes a dry ice automatic discharging device based on a cold quantity matching mode to quantitatively add cold source dry ice into ultralow-temperature food-grade non-freezing liquid, and the cold quantity is released by vaporization in the non-freezing liquid, so that the secondary refrigerant is balanced in real time to keep the ultralow-temperature constant freezing temperature, and the food materials can be frozen in different periods of time to realize no difference in muscle ice crystal generation; in addition, the invention also clarifies the mathematical problems of the cold quantity released by the dry ice in the process of freezing food by the dry ice coupling non-freezing liquid, heat exchange in the process of freezing food and the like; the freezing technology is novel and environment-friendly, and fills the blank in the field of food freezing.
Description
Technical Field
The invention belongs to the technical field of food freezing and fresh-keeping processing, and particularly relates to a constant-temperature dipping green ultralow-temperature freezing method for coupling a non-freezing liquid secondary refrigerant with dry ice.
Background
In recent years, the demands of people on quick-frozen foods are increasing, and the variety of quick-frozen foods is also increasing, so that livestock products, vegetables, fruits, rice and flour products and the like are covered. The requirements of quick-frozen foods promote the rapid development of food quick-freezing technology, and the traditional freezing modes, such as plate freezing, tunnel freezing and the like, have the defects of low freezing rate, high food material dry consumption, reduced food quality after freezing and the like. The liquid soaking and freezing technology is quick freezing technology with fast freezing speed, small food consumption, homogeneous freezing and low production cost. In low-temperature rapid soaking and freezing, the freezing-free liquid soaking and freezing mode is considered to be a novel and efficient low-temperature fresh-keeping processing technology because of high cold storage density, large heat transfer coefficient (20 times higher than that of an air medium) and high freezing speed. The non-freezing liquid has the advantages of low freezing point, large heat transfer coefficient, safety, no toxicity, effective maintenance of food quality, prolonged food shelf life and the like; although the liquid nitrogen immersion freezing can realize the rapid low-temperature freezing of food, the mechanical stress on the surface of the frozen material is too large and Wen Donglie is low due to the intense heat exchange with the food material; meanwhile, the size of the food materials is limited to a certain extent, and when the size of the food materials is large, the problems of frost cracking, freeze burning and the like on the surface of the food are caused after freezing.
CO 2 Colorless and odorless gas at normal temperature and normal pressure, and exists in solid state when the temperature is-56.6 ℃ and the pressure is 0.52MPa, namely 'dry ice'. Solid CO 2 The sublimation temperature of the material is low and is-78.5 ℃, and the purposes of rapid temperature reduction and refrigeration can be realized. And CO 2 The product has stable property, is not easy to react with components in the food materials when in direct contact with the food materials, can well maintain the original flavor and quality of the materials, and can be widely applied to food preservation.
The method mainly utilizes the fact that the dry ice has larger vaporization latent heat and lower vaporization temperature, can promote the quick cooling of the unfrozen liquid, and defines the heat exchange and the addition amount of the dry ice in the freezing process of the dry ice coupling unfrozen liquid; the dry ice has the advantages of low price and environmental protection, and can be sublimated into gas rapidly, so that the environment is not polluted; the method has high freezing speed, and really realizes low-temperature quick freezing processing through short time of the maximum ice crystal generation area. The real-time balance secondary refrigerant keeps ultralow temperature constant freezing temperature, and the fish body can be frozen in different periods of time to realize no difference in generation of muscle ice crystals, so that the quality of frozen-thawed food is ensured.
Disclosure of Invention
Aiming at the defects existing in the prior art, the invention provides a constant-temperature dipping green ultralow-temperature freezing method for coupling a non-freezing liquid secondary refrigerant with dry ice.
The technical scheme of the invention is as follows:
a constant-temperature dipping green ultralow-temperature freezing method of non-freezing liquid secondary refrigerant coupled dry ice comprises the following steps:
1) Cleaning food materials, and wrapping the food materials with a preservative film;
the food material is fresh food;
2) Precooling the food materials to a central temperature of 2+/-0.5 ℃ by using fluidized ice, and recording the temperature change of the food materials by using a temperature recorder;
the fluidized ice is a common food precooling means, and the main components of the fluidized ice are water and salt;
3) Cooling the non-freezing liquid to the set temperature of-45 ℃ by using low-temperature constant-temperature reaction bath equipment, and recording the temperature change by using a temperature recorder;
the unfrozen liquid is food-grade unfrozen liquid which is generally used for immersing and freezing food materials, achieves the effects of quick freezing and fresh keeping, and can be obtained commercially;
4) Dipping and freezing dry ice coupling non-freezing liquid: immersing and freezing the food material precooled in the step 2) in the unfrozen liquid cooled in the step 3), and simultaneously adding dry ice;
in the step, cold source dry ice (the vaporization latent heat is 573kJ/kg, the vaporization temperature is-78.5 ℃) can be quantitatively added into the non-freezing liquid (the temperature is less than or equal to-45 ℃) of the ultralow temperature food by using a dry ice automatic discharging device based on a cold amount matching mode, and meanwhile, stirring is carried out, the cold amount is released by vaporization in the non-freezing liquid, and the ultralow temperature constant freezing temperature is kept by balancing the secondary refrigerant in real time;
the dry ice can be in the form of particles, blocks, flakes, columns, more preferably columnar dry ice;
5) Recording the change of the temperature of the center of the food material in the step 4) by using a temperature recorder, and ending freezing when the temperature of the center of the food material reaches the target temperature.
In the method of the invention, the heat transfer and dry ice addition amount in the food material freezing process can be determined by the following steps:
s1, firstly, determining the mass and specific heat capacity of food materials to be frozen;
s2, determining a target freezing temperature of the geometric center of the food material;
s3, determining heat released by the fact that the temperature of the center of the food material is reduced from the temperature before freezing to the target temperature:
Q 1 ＝c 1 M 1 Δt 1
in which Q 1 The total heat released by the food materials in the freezing process is as follows: j; c 1 The specific heat capacity of the food material is as follows: j/(kg. DEG C); m is M 1 The mass of the food material is as follows: kg; Δt (delta t) 1 The unit is the temperature change in the freezing process of food materials: the temperature is lower than the temperature;
s4, determining a total heat expression absorbed in the process of increasing the temperature of the non-freezing liquid in the device, wherein the total heat expression is as follows:
Q 2 ＝c 2 M 2 Δt 2
in which Q 2 The total heat absorbed in the cooling process of the non-freezing liquid is as follows: j; c 2 Specific heat capacity of the non-freezing liquid is as follows: j/(kg. DEG C); m is M 2 The mass of the non-freezing liquid is as follows: kg; Δt (delta t) 2 The unit is the temperature change of the non-freezing liquid: the temperature is lower than the temperature;
s5, determining the total cold released after dry ice is added:
Q 3 ＝573m
in which Q 3 Cooling capacity released for dry ice, unit: j;573 is the amount of heat absorbed by sublimation of dry ice per unit mass, in units of: kJ/kg; m is the mass of dry ice added, unit: kg;
s6, determining an energy conservation equation of the material in the freezing process of the non-frozen liquid before adding the dry ice, wherein according to the energy conservation law, the absorbed heat is equal to the released heat in equation (1):
Q 11 ＝Q 21 +Q 4
in which Q 11 Heat released by food materials in the freezing process before dry ice is added is given in units: j; q (Q) 21 For the heat absorbed in the process of cooling the non-frozen liquid, the unit is: j; q (Q) 4 The refrigerating capacity of the non-freezing liquid equipment is as follows: w is a metal;
s7, when dry ice is added, an energy conservation formula (2) of the whole system is as follows:
Q 22 ＝Q 3 +Q 4 -Q 12
in which Q 12 The heat released in the freezing process of the food materials after the dry ice is added is given in units: j; q (Q) 22 The total heat absorbed in the process of cooling the non-frozen liquid is as follows: j; q (Q) 3 Cooling capacity released for dry ice, unit: j; q (Q) 4 The refrigerating capacity of the non-freezing liquid equipment is as follows: w is a metal;
s8, when the dry ice is volatilized, an energy conservation formula (3) of the whole system is as follows:
Q 23 +Q 4 ＝Q 13
in which Q 13 The unit is the cold quantity absorbed by food materials in the freezing process: j; q (Q) 23 The total heat released in the temperature rising process of the non-freezing liquid is as follows: j; q (Q) 4 The refrigerating capacity of the non-freezing liquid equipment is as follows: w is a metal;
s9, the heat exchange amount of the material and the dry ice in the whole freezing process is as follows:
Q 1 ＝Q 11 +Q 12 +Q 13 ＝Q 3 +3Q 4
the dry ice addition amount can be determined
In which Q 1 The total heat released by the food materials in the freezing process is as follows: j; q (Q) 3 Cooling capacity released for dry ice, unit: j: q (Q) 4 The refrigerating capacity of the non-freezing liquid equipment is as follows: J.
the invention has the beneficial effects that:
the invention provides a dry productThe ice is used as a cold source, a constant-temperature immersion green ultralow-temperature freezing technology of the unfrozen liquid is combined, cold source dry ice (the vaporization latent heat is 573kJ/kg and the vaporization temperature is-78.5 ℃) is quantitatively added into the ultralow-temperature food-grade unfrozen liquid (the temperature is less than or equal to-45 ℃) by utilizing a dry ice automatic discharging device based on a cold amount matching mode, the cold amount is released by vaporization in the unfrozen liquid, the real-time balance refrigerating medium keeps the ultralow-temperature constant freezing temperature, and the fish body can be frozen in different periods without difference in muscle ice crystal generation. CO formed after sublimation of dry ice 2 The gas exists in the unfrozen liquid in the form of bubbles, and plays a role in stirring the unfrozen liquid along with the continuous generation of the bubbles, so as to achieve the effect of stabilizing the temperature of the unfrozen liquid. Better solves the problem of temperature fluctuation in the process of immersing and freezing food in the non-freezing liquid.
In addition, the invention also clarifies the mathematical problems of the cold quantity released by the dry ice in the process of freezing food by the dry ice coupling non-freezing liquid, heat exchange in the process of freezing food and the like. The invention uses the non-freezing liquid to couple with dry ice to realize quick low-temperature freezing of food, not only can reduce the size of ice crystals in frozen products and the damage of the ice crystals to tissue structures, but also can improve the freezing rate, balance the frozen medium in real time to keep the ultralow temperature constant freezing temperature, and the fish body can realize the non-difference of the generation of muscle ice crystals in different periods of time and keep the quality of the food. The freezing technology is novel and environment-friendly, and fills the blank in the field of food freezing.
Drawings
FIG. 1 is a schematic diagram of an experimental apparatus according to the present invention.
Fig. 2 is a schematic diagram showing temperature change curves of fish body and unfrozen liquid in the freezing process of the invention: wherein the X-axis represents time, units: min; the Y-axis represents temperature, unit: the temperature is lower than the temperature; t (T) 0 Represents the initial temperature of the large yellow croaker before freezing in units of: the temperature is lower than the temperature; t (T) 1 Represents the center temperature at the end of the precooling of the large yellow croaker in units of: the temperature is lower than the temperature; t (T) 2 Represents the center temperature in units of when the large yellow croaker is frozen: the temperature is lower than the temperature; t is t a Represents the time point of dry ice addition, unit: min; t is t b Represents the time in units of minimum temperature of the non-frozen liquid: min; t is t c Time representing the end of the freezing of large yellow croaker, unit: min; t (T) a Represents the set temperature reached by the unfrozen liquid, unit: the temperature is lower than the temperature; t (T) b Represents the temperature in units of the unfrozen liquid when the temperature is raised to the temperature at which dry ice is required to be added: the temperature is lower than the temperature; t (T) c Represents the minimum temperature reached by the non-frozen liquid in units of: DEG C.
FIG. 3 is a schematic diagram showing endogenous fluorescence of myofibrillar proteins of large yellow croaker in three different freezing modes according to examples and comparative examples of the present invention: wherein A is-40deg.C, freezing yellow croaker in refrigerator to-18deg.C; b1 and B2 are respectively that the center temperature of the yellow croaker is frozen to-18 ℃ and-30 ℃ by a non-frozen liquid without adding dry ice at-45 ℃; c1 and C2 are respectively the temperatures of the center of the yellow croaker frozen by the non-frozen liquid added with dry ice at the temperature of minus 45 ℃ to minus 18 ℃ and minus 30 ℃.
FIG. 4 is a graph showing the freezing curves of large yellow croaker in three different freezing modes according to examples and comparative examples of the present invention.
Detailed Description
The present invention is further described below by way of specific examples, but the scope of the present invention is not limited thereto.
The non-freezing liquid used in the following examples was supplied by Qianlia lake development group Co., hangzhou, and had a freezing point of-48.6 ℃.
Example 1: non-freezing liquid without dry ice for immersing and freezing large yellow croaker
1) Pretreatment of large yellow croaker: washing fresh large yellow croaker with clear water, wrapping with a preservative film, putting into fluid ice with the salt concentration of about 3.5%, and precooling until the central temperature is 2+/-0.5 ℃;
2) Immersing and freezing treatment of the non-freezing liquid: and (3) immersing the pre-cooled fish in a non-freezing liquid for quick freezing, inserting a temperature measuring probe into the geometric center position of the fish slices, recording the temperature, and ending freezing when the center temperature of the fish slices is respectively frozen to-18 ℃ and-30 ℃. The time for passing through the maximum ice crystal generation zone in the freezing mode is only 12.4min, and the conventional refrigerator needs 257min or so for freezing.
Example 2: non-freezing liquid added with dry ice is used for immersing and freezing large yellow croaker fillets
1) Pretreatment of large yellow croaker: fresh large yellow croaker is washed clean by clear water, wrapped by a preservative film, placed into fluid ice (the main components of the fluid ice are water and salt), and precooled until the central temperature is 2+/-0.5 ℃.
2) Immersing and freezing treatment of the non-freezing liquid: wrapping and immersing the precooled fish in food grade unfrozen liquid at-45 ℃ by using a preservative film, quantitatively adding cold source dry ice (573 kJ/kg of vaporization latent heat and-78.5 ℃) into the ultralow temperature food grade unfrozen liquid (the temperature is less than or equal to-45 ℃) by using a dry ice automatic discharging device based on a cold quantity matching mode, stirring the unfrozen liquid by using a stirrer, recording the temperature at the geometrical center position of the yellow croaker by inserting a temperature measuring probe, and ending freezing when the center temperature of the fish body is respectively frozen to-18 ℃ and-30 ℃. The freezing technology of the embodiment only needs 6.4min for freezing fillets to pass through the maximum ice crystal generation zone, and the traditional refrigerator needs about 257min for freezing, so that the technology really realizes low-temperature quick freezing processing through the short maximum ice crystal generation zone.
3) The method for determining the heat transfer of the large yellow croaker in the freezing process, the refrigerating capacity of the dry ice and the addition amount of the large yellow croaker comprises the following steps:
s1, firstly, determining the mass and specific heat capacity of the large yellow croaker to be frozen;
s2, determining a target freezing temperature of the geometric center of the large yellow croaker;
s3, determining heat released by the fact that the center temperature of the large yellow croaker is reduced from 2 ℃ to the target temperature:
Q 1 ＝c 1 M 1 Δt 1 ＝c 1 M 1 (T 1 -T 2 )
in which Q 1 The total heat released by the large yellow croaker in the freezing process is as follows: j; c is the specific heat capacity (3.18J/(kg. DEG C)) of the large yellow croaker; m is M 1 Is the mass (8.80 kg) of the large yellow croaker; t (T) 2 The center temperature (-18 ℃) of the large yellow croaker at the end of freezing; t (T) 1 The center temperature (2 ℃) of the large yellow croaker before freezing. I.e. the total heat released by the large yellow croaker during freezing is 559.68J.
S4, determining 0 to t a The energy conservation equation of the material in the freezing process of the non-frozen liquid in the process (before adding dry ice) is that according to the energy conservation law, the absorbed heat is equal to the released heat in the following equation (1):
Q 11 ＝Q 21 +Q 4
in which Q 11 In order to prevent the frozen liquid from freezing the heat released in the process of the large yellow croaker before adding the dry ice, the unit is: j; q (Q) 21 For the heat absorbed in the process of cooling the non-frozen liquid, the unit is: j; q (Q) 4 The refrigerating capacity of the non-freezing liquid equipment is as follows: w.
S5, determining t a ～t b In the process (after dry ice is added), the energy conservation formula (2) of the whole system is as follows:
Q 22 ＝Q 3 +Q 4 -Q 12
in which Q 12 The heat released in the freezing process of the food materials after the dry ice is added is given in units: j; q (Q) 22 The total heat absorbed in the process of cooling the non-frozen liquid is as follows: j; q (Q) 3 Cooling capacity released for dry ice, unit: j; q (Q) 4 The refrigerating capacity of the non-freezing liquid equipment is as follows: w.
S6: determining t a ～t b In the process of volatilizing the dry ice, the energy conservation formula (3) of the whole system is as follows:
Q 23 +Q 4 ＝Q 13
in which Q 13 The unit is the cold quantity absorbed by food materials in the freezing process: j; q (Q) 23 The total heat released in the temperature rising process of the non-freezing liquid is as follows: j; q (Q) 4 The refrigerating capacity of the non-freezing liquid equipment is as follows: w.
S9: the heat exchange amount of the material and the dry ice in the whole freezing process is determined as follows:
the dry ice addition amount can be determined
In which Q 1 The total heat released by the large yellow croaker in the freezing process is 559.68J; p is the output power of the non-freezing liquid equipment, which is 200J/s;573 is the amount of heat absorbed by sublimation of dry ice per unit mass, in units of: kJ/kg;t 1 the freezing time of the large yellow croaker was 20 minutes, and thus the dry ice addition amount was calculated to be 0.86kg.
Therefore, in the embodiment, when the initial temperature of the frozen food material is 2+/-0.5 ℃ and the mass of the material is 8.8kg, the stability of the temperature of the non-frozen liquid can be better maintained after 0.86kg of dry ice is added, the temperature fluctuation of the non-frozen liquid in the freezing process is reduced, and the freezing rate is improved.
Comparative example 1:
1) Pretreatment of large yellow croaker: fresh large yellow croaker is cleaned, wrapped by a preservative film, placed into fluid ice, and precooled until the central temperature is 2+/-0.5 ℃.
2) Freezing treatment of a refrigerator: and (3) putting the precooled fish into a self-sealing bag, freezing in a refrigerator at the temperature of minus 40 ℃, recording the temperature at the geometric center position of the inserted fish slices by a temperature measuring probe, and ending the freezing when the center temperature of the fish slices is frozen to minus 18 ℃.
Determination of myofibrillar protein tertiary structure of large yellow croaker: the concentration of the extracted myofibrillar protein is regulated to 0.5mg/mL, an endogenous fluorescence spectrometer is used for carrying out spectrum scanning, the scanning range is 300 nm-500 nm, the emission spectrum range is 300 nm-400 nm, the excitation wavelength is 293nm, the excitation slit is 10nm, the emission slit is 10nm, and the scanning is repeated for 3 times. The result is that the endogenous fluorescence map of myofibrillar proteins is drawn with the wave number as the abscissa and the fluorescence intensity as the ordinate. As shown in FIG. 3, the fluorescence intensity of myofibrillar proteins of large yellow croaker frozen by the non-frozen solution after dry ice addition is highest, and the tertiary structure of the proteins is relatively stable.
Determination of the freezing curve of large yellow croaker: the temperature probe is inserted into the geometric center of the fish body, and the computer is connected with the temperature recorder to collect the temperature data in the example 1, the example 2 and the comparative experiment 1 in real time. And drawing a time-temperature curve by taking time as an abscissa and temperature as an ordinate, namely the freezing curve of the large yellow croaker. As can be seen from fig. 4, the freezing rate of the unfrozen liquid after adding dry ice can be significantly improved.
Claims (3)
1. The constant-temperature immersed green ultralow-temperature freezing method of the non-freezing liquid secondary refrigerant coupled dry ice is characterized by comprising the following steps of:
1) Cleaning food materials, and wrapping the food materials with a preservative film;
2) Precooling the food materials to a central temperature of 2+/-0.5 ℃ by using fluidized ice, and recording the temperature change of the food materials by using a temperature recorder;
3) Cooling the non-freezing liquid to the set temperature of-45 ℃ by using low-temperature constant-temperature reaction bath equipment, and recording the temperature change by using a temperature recorder;
4) Dipping and freezing dry ice coupling non-freezing liquid: immersing and freezing the food material precooled in the step 2) in the unfrozen liquid cooled in the step 3), and simultaneously adding dry ice;
5) Recording the change of the temperature of the center of the food material in the step 4) by using a temperature recorder, and ending freezing when the temperature of the center of the food material reaches the target temperature.
2. The constant temperature immersion green ultralow temperature freezing method of the non-frozen liquid secondary refrigerant coupled dry ice according to claim 1, wherein the dry ice is quantitatively added into the non-frozen liquid by using a dry ice automatic discharging device based on a refrigerating capacity matching mode, and the non-frozen liquid is stirred at the same time;
the heat transfer and dry ice addition amount of the food material freezing process is determined by the following steps:
s1, firstly, determining the mass and specific heat capacity of food materials to be frozen;
s2, determining a target freezing temperature of the geometric center of the food material;
s3, determining heat released by the fact that the temperature of the center of the food material is reduced from the temperature before freezing to the target temperature:
Q 1 ＝c 1 M 1 Δt 1
in which Q 1 The total heat released by the food materials in the freezing process is as follows: j; c 1 The specific heat capacity of the food material is as follows: j/(kg. DEG C); m is M 1 The mass of the food material is as follows: kg; Δt (delta t) 1 The unit is the temperature change in the freezing process of food materials: the temperature is lower than the temperature;
s4, determining a total heat expression absorbed in the process of increasing the temperature of the non-freezing liquid in the device, wherein the total heat expression is as follows:
Q 2 ＝c 2 M 2 Δt 2
in which Q 2 The total heat absorbed in the cooling process of the non-freezing liquid is as follows: j; c 2 Specific heat capacity of the non-freezing liquid is as follows: j/(kg. DEG C); m is M 2 The mass of the non-freezing liquid is as follows: kg; Δt (delta t) 2 The unit is the temperature change of the non-freezing liquid: the temperature is lower than the temperature;
s5, determining the total cold released after dry ice is added:
Q 3 ＝573m
in which Q 3 Cooling capacity released for dry ice, unit: j;573 is the amount of heat absorbed by sublimation of dry ice per unit mass, in units of: kJ/kg; m is the mass of dry ice added, unit: kg;
s6, determining an energy conservation equation of the material in the freezing process of the non-frozen liquid before adding the dry ice, wherein according to the energy conservation law, the absorbed heat is equal to the released heat in equation (1):
Q 11 ＝Q 21 +Q 4
in which Q 11 Heat released by food materials in the freezing process before dry ice is added is given in units: j; q (Q) 21 For the heat absorbed in the process of cooling the non-frozen liquid, the unit is: j; q (Q) 4 The refrigerating capacity of the non-freezing liquid equipment is as follows: w is a metal;
s7, when dry ice is added, an energy conservation formula (2) of the whole system is as follows:
Q 22 ＝Q 3 +Q 4 -Q 12
in which Q 12 The heat released in the freezing process of the food materials after the dry ice is added is given in units: j; q (Q) 22 The total heat absorbed in the process of cooling the non-frozen liquid is as follows: j; q (Q) 3 Cooling capacity released for dry ice, unit: j; q (Q) 4 The refrigerating capacity of the non-freezing liquid equipment is as follows: w is a metal;
s8, when the dry ice is volatilized, an energy conservation formula (3) of the whole system is as follows:
Q 23 +Q 4 ＝Q 13
in which Q 13 Is edibleThe cold quantity absorbed by the product material in the freezing process is as follows: j; q (Q) 23 The total heat released in the temperature rising process of the non-freezing liquid is as follows: j; q (Q) 4 The refrigerating capacity of the non-freezing liquid equipment is as follows: w is a metal;
s9, the heat exchange amount of the material and the dry ice in the whole freezing process is as follows:
Q 1 ＝Q 11 +Q 12 +Q 13 ＝Q 3 +3Q 4
the dry ice addition amount can be determined
In which Q 1 The total heat released by the food materials in the freezing process is as follows: j; q (Q) 3 Cooling capacity released for dry ice, unit: j: q (Q) 4 The refrigerating capacity of the non-freezing liquid equipment is as follows: J.
3. a constant temperature immersion green ultra-low temperature freezing method of non-freezing liquid secondary refrigerant coupled dry ice as claimed in claim 1, wherein the dry ice is in the form of particles, blocks, flakes or columns.
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