Optimization method of temperature control index of outlet of large-volume concrete mixing plant

Abstract

The present invention provides a method for optimizing the temperature control index at the outlet of a large-volume concrete mixing plant, namely: first, according to the configuration of the aggregate air cooling system, the cooling water system and the ice-making system of the mixing plant at the project site, the upper and lower limits of the aggregate temperature and the cooling water temperature, as well as the upper limit of the ice-adding rate are determined; then, a temperature calculation model and a temperature control cost function for the outlet of a large-volume concrete mixing plant are established; various temperature control index values ​​that meet the target temperature requirements of the outlet of the mixing plant are determined; various temperature control index values ​​are arranged and combined to calculate the temperature control cost; finally, a group of temperature control index values ​​with the lowest temperature control cost is selected as the optimal temperature control index. Advantages of the present invention: 1. It is highly scientific and avoids blindness and arbitrariness. 2. The temperature control measures formulated according to the temperature control index determined by the present invention have the lowest cost.

Description

Technical Field

[0001] The invention relates to a method for optimizing temperature control index of a large-volume concrete mixing plant outlet. Background Art

[0002] In order to reduce the hydration reaction temperature of large-volume concrete and prevent or reduce the occurrence of temperature cracks, it is necessary to take temperature control measures in the concrete mixing, transportation, pouring and other links, especially the setting of the outlet temperature of the large-volume concrete mixing plant. The lower the temperature of the mixing plant outlet, the lower the maximum temperature of the large-volume concrete hydration reaction, the smaller the temperature difference between the inside and outside, and the smaller the probability of temperature cracks. Therefore, it is particularly important to take temperature control measures at the mixing plant outlet to reduce the temperature of the mixing plant outlet.

[0003] At present, the formulation of temperature control measures at the outlet of large-volume concrete mixing plants, especially the formulation of temperature control indicators at the outlet of mixing plants, has the following problems: 1. It is very arbitrary. It is mainly reflected in: when formulating the temperature control indicators at the outlet of mixing plants, the setting of the outlet temperature is completely based on engineering experience. The precooling temperature of the mixing aggregate, the cooling water temperature and the ice addition rate are simply set according to the target temperature of the outlet of the mixing plant. It lacks scientificity, logic, and rationality, and is too arbitrary. 2. There is no scientific basis for the adjustment range of the temperature control indicators at the outlet of the mixing plant. In actual projects, technicians blindly adjust the air cooling temperature, cooling water temperature and ice addition rate, resulting in the precooling amount required for the temperature control measures exceeding the rated cooling capacity of the system configuration, which leads to the inadequate temperature control measures and poor temperature control effect. 3. The cooling cost of each temperature control measure is not considered, and only the target temperature of the outlet is used as the only judgment standard. In this way, although the target temperature of the outlet of the large-volume concrete mixing plant meets the requirements, the temperature control measures are often not the optimal combination, resulting in a high cost of the temperature control measures. Summary of the invention

[0004] In view of the above reasons, the purpose of the present invention is to provide a method for optimizing the temperature control index of the outlet of a large-volume concrete mixing plant, so as to provide a scientific basis for the formulation of temperature control measures for the outlet of the mixing plant.

[0005] To achieve the above purpose, the present invention adopts the following technical solution: a method for optimizing the temperature control index of the outlet of a large-volume concrete mixing plant, namely:

[0006] S1. Determine the upper limit value T of aggregate temperature according to the configuration of aggregate air cooling system of mixing plant at the project site. g·max and the lower limit T g·min , according to the configuration of the cooling water system on the project site, determine the upper limit value T of the cooling water temperature w·max and the lower limit T w·min , according to the configuration of the ice making system on the project site, determine the upper limit of the ice adding rate α max ;

[0007] S2. Establish a temperature calculation model for the mixing plant outlet. The temperature calculation model for the mixing plant outlet is:

[0008]

[0009] Among them, T 0 T is the outlet temperature of mixing plant; w is the cooling water temperature; T g is the aggregate temperature; T s is the cement temperature; T c is the sand temperature; T f is the fly ash temperature; T ice is the flake ice temperature, take -5℃; G w is the weight of water in concrete; G g is the weight of aggregate in concrete; G s is the weight of cement in concrete; G c is the weight of sand in concrete; G f is the fly ash mass; γ g is the moisture content of aggregate; c is the moisture content of sand; c w is the specific heat of water; c g is the specific heat of aggregate; c s is the specific heat of cement; c c is the specific heat of sand; c f is the specific heat of fly ash; c ice is the specific heat of flake ice; 335 is the latent heat of melting of ice; Q is the mechanical heat generated when concrete is mixed; α is the ice addition rate;

[0010] S3. Establish the functional relationship between aggregate temperature, cooling water temperature, ice addition rate and temperature control cost:

[0011] P i =p w (T w -T wi )(1-α i )G w +p g (T g -T gi )G g +p ice α i G w

[0012] Where P i is the temperature control cost; p w The unit price for cooling 1℃ per kilogram of cooling water; p ice is the unit price per kilogram of flake ice; p g The unit price for cooling 1℃ per kg of aggregate by air cooling; Gw is the weight of water in each cubic meter of concrete; G g is the weight of aggregate in each cubic meter of concrete; T w is the initial temperature of cooling water; T g is the initial temperature of aggregate; T wi : is the temperature of the cooling water after refrigeration; T gi is the temperature of aggregate after air cooling; α i is the ice addition rate;

[0013] S4. Substitute the upper limit and lower limit of the temperature control index determined in step S1 into the temperature calculation model of the mixing plant outlet in step S2 to determine the values ​​of various temperature control indexes that meet the outlet target temperature requirements; the specific calculation method is as follows:

[0014] S4.1. Divide the aggregate temperature interval n into equal parts, obtain the aggregate temperature increment Δa, and calculate the aggregate temperature T gi , divide the cooling water temperature interval n into equal parts, obtain the cooling water temperature increment Δb, and calculate the cooling water temperature T wi , divide the ice adding rate interval n into equal parts, obtain the ice adding rate increment Δc, and calculate the ice adding rate α used i , the specific calculation formula is as follows:

[0015]

[0016]

[0017]

[0018] T gi =T g·min +(i-1)Δa i=1,2…n

[0019] T wi =T w·min +(i-1)Δb i=1,2…n

[0020] α i =α min +(i-1)Δc i=1,2…n

[0021] Where Δa is the temperature increment of aggregate; Δb is the temperature increment of cooling water; Δc is the increment of ice addition rate; T g·min is the lower limit of aggregate temperature; T g·max is the upper limit of aggregate temperature; T w·min is the lower limit of cooling water temperature; T w·max is the upper limit of cooling water temperature, α max is the upper limit of ice adding rate; T gi is the aggregate temperature; T wiis the cooling water temperature; i Ice rate;

[0022] S4.2. The aggregate temperature T calculated in step S4.1 is gi , cooling water temperature T wi and ice rate α i Perform permutations and combinations, substitute all permutation and combination data into the mixing plant outlet temperature calculation model in step S2, and calculate the mixing plant outlet temperature;

[0023] When the variables are combined, the outlet temperature of the mixing plant T is calculated. 0 Greater than the allowable outlet temperature T N , less than or equal to the outlet target temperature T M When the aggregate temperature, cooling water temperature and ice addition rate of this group of variable combinations are retained; when the outlet temperature T of the mixing plant calculated after the variable combination 0 Greater than the outlet target temperature T M , then discard the variable combination;

[0024] S5. According to the temperature control cost function relationship in step S3, calculate the temperature control costs of all variable combinations that meet the outlet target temperature in step S4.2, and select the variable combination with the smallest temperature control cost as the optimal temperature control index after the outlet temperature is optimized.

[0025] In a preferred embodiment of the present invention, the upper limit value T of the aggregate temperature is determined in step S1. g·max and the lower limit T g·min The method is:

[0026] The average temperature of aggregate before it is put into the air cooling bin of the aggregate air cooling system is taken as the upper limit value of aggregate temperature T. g·max ;

[0027] Determine the rated cooling capacity Q of the air cooling system output according to the configuration of the aggregate air cooling system g , determine the mass of aggregate that needs to be air-cooled per hour based on the mixing strength m g , calculate the maximum temperature drop of aggregate Δt g , determine the lower limit of aggregate temperature T g·min , the specific calculation formula is as follows:

[0028]

[0029] T g·min =T g·max -Δt g

[0030] Where: Δt g is the maximum temperature drop of aggregate; Q g is the rated cooling capacity of the aggregate air cooling system; cg is the specific heat capacity of aggregate; m g The mass of aggregate that needs to be air-cooled per hour; T g·min is the lower limit of aggregate temperature; T g·max is the upper limit of aggregate temperature.

[0031] In a preferred embodiment of the present invention, the upper limit value T of the cooling water temperature is determined in step S1. w·max and the lower limit T w·min The method is:

[0032] Collect the water temperature of the mixing water tank as the upper limit value T of the cooling water temperature w·max ;

[0033] Determine the rated cooling capacity Q of the cooling water system according to its configuration w , according to the mixing intensity, determine the mass of cooling water required per hour m w , calculate the maximum cooling amplitude Δt of the cooling water w , determine the lower limit of cooling water temperature T w·min , the specific calculation formula is as follows:

[0034]

[0035] T w·min =T w·max -Δt w

[0036] Where: Δt w is the maximum temperature drop of cooling water; Q w is the rated cooling capacity of the cooling water system; c w is the specific heat capacity of water; m w is the mass of cooling water required per hour; T w·min is the lower limit of cooling water temperature; T w·max It is the upper limit of cooling water temperature.

[0037] In a preferred embodiment of the present invention, the upper limit value α of the ice adding rate is determined in step S1. max The method is:

[0038] Determine the rated ice making capacity Q of the ice making system according to the configuration of the ice making system on the project site ice , calculate the ice output per hour m ice , and then determine the mass m of cooling water required per hour based on the mixing intensity w , calculate the maximum ice adding rate, that is, the upper limit of ice adding rate α max , the specific calculation formula is as follows:

[0039]

[0040]

[0041] Where: Q ice Rated ice making capacity for ice making system; m ice The amount of ice produced per hour by the ice making system; c w is the specific heat capacity of water; Δt ice Δt is the temperature difference between water and flake ice. Usually, 2°C water is used to make -8°C flake ice. ice Take 10℃; 335 is the latent heat of phase change of water from solid to liquid; α max is the upper limit of ice adding rate; m w The mass of cooling water required per hour.

[0042] Compared with the traditional method for formulating temperature control indicators at the outlet of a large-volume concrete mixing plant, the present invention has the following advantages: 1. Before adjusting the temperature control parameters, the adjustment range of each temperature control indicator is determined by the configuration of the air cooling system, cooling water system and ice making system of the mixing plant and the hourly concrete production intensity, thereby avoiding the problem that the temperature control measures are not implemented properly and the temperature control effect is not ideal due to the cooling capacity required for the temperature control measures exceeding the rated cooling capacity of the system. 2. By calculating the cooling cost of each temperature control measure, the optimal temperature control indicator is determined on the premise of meeting the temperature control requirements, thereby saving engineering costs. 3. It is highly scientific and avoids blindness and arbitrariness. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a flow chart of the method for optimizing the temperature control index of the outlet of a large-volume concrete mixing plant of the present invention;

[0044] Figure 2 A flow chart of the method for determining the minimum temperature control cost of the present invention. DETAILED DESCRIPTION

[0045] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments. It should be noted that various modifications can be made to the embodiments disclosed herein, and therefore, the embodiments disclosed in the specification should not be regarded as limiting the present invention, but are merely examples of embodiments, the purpose of which is to make the features of the present invention apparent.

[0046] Concrete mixing plant is a device that mixes and stirs aggregate (large, medium and small stones), cement, sand and water to produce concrete. In order to reduce the hydration reaction temperature of concrete, the aggregates, especially large and medium aggregates, need to be cooled by air once and twice before being put into the mixing plant. The water added is cooling water. In order to further control the hydration reaction temperature of concrete, ice cubes need to be added during the process of mixing materials in the mixing plant to produce concrete to reduce the hydration reaction temperature of concrete. How to set the aggregate temperature, cooling water temperature and ice addition rate in the temperature control measures will affect the temperature control effect.

[0047] like Figure 1 As shown, the method for optimizing the temperature control index of the outlet of a large-volume concrete mixing plant disclosed in the present invention is:

[0048] S1. Determine the upper limit value T of aggregate temperature according to the configuration of aggregate air cooling system of mixing plant at the project site. g·max and the lower limit T g·min , according to the configuration of the cooling water system on the project site, determine the upper limit value T of the cooling water temperature w·max and the lower limit T w·min , and determine the upper limit of ice adding rate α according to the configuration of ice making system at the project site max .

[0049] S1.1. Determine the upper limit value T of aggregate temperature g·max and the lower limit T g·min .

[0050] The average temperature of aggregate before it is put into the air cooling bin of the aggregate air cooling system is taken as the upper limit value of aggregate temperature T. g·max .

[0051] Determine the rated cooling capacity Q of the air cooling system output according to the configuration of the aggregate air cooling system g , determine the mass of aggregate that needs to be air-cooled per hour based on the mixing strength m g , calculate the maximum temperature drop of aggregate Δt g , determine the lower limit of aggregate temperature T g·min , the specific calculation formula is as follows:

[0052]

[0053] T g·min =T g·max -Δt g

[0054] Where: Δt g is the maximum temperature drop of aggregate; Q g is the rated cooling capacity of the aggregate air cooling system; c g is the specific heat capacity of aggregate; m g The mass of aggregate that needs to be air-cooled per hour; T g·min is the lower limit of aggregate temperature; T g·max is the upper limit of aggregate temperature

[0055] S1.2. Determine the upper limit value T of the cooling water temperature w·max and the lower limit T w·min .

[0056] Collect the water temperature of the mixing water tank as the upper limit value T of the cooling water temperature w·max .

[0057] Determine the rated cooling capacity Q of the cooling water system according to its configuration w , according to the mixing intensity, determine the mass of cooling water required per hour m w , calculate the maximum cooling amplitude Δt of the cooling water w , determine the lower limit of cooling water temperature T w·min , the specific calculation formula is as follows:

[0058]

[0059] T w·min =T w·max -Δt w

[0060] Where: Δt w is the maximum temperature drop of cooling water; Q w is the rated cooling capacity of the cooling water system; c w is the specific heat capacity of water; m w is the mass of cooling water required per hour; T w·min is the lower limit of cooling water temperature; T w·max The upper limit of cooling water temperature

[0061] S1.3. Determine the upper limit of ice addition rate α max .

[0062] Determine the rated ice making capacity Q of the ice making system according to the configuration of the ice making system on the project site ice , calculate the ice output per hour m ice , and then determine the mass m of cooling water required per hour based on the mixing intensity w , calculate the maximum ice adding rate, that is, the upper limit of ice adding rate α max , the specific calculation formula is as follows:

[0063]

[0064]

[0065] Where: Q ice Rated ice making capacity for ice making system; m ice The amount of ice produced per hour by the ice making system; c w is the specific heat capacity of water;

[0066] Δt ice Δt is the temperature difference between water and flake ice. Usually, 2°C water is used to make -8°C flake ice. ice Take 10℃; 335 is the latent heat of phase change of water from solid to liquid; α max is the upper limit of ice adding rate; m w The mass of cooling water required per hour.

[0067] S2. Establish a temperature calculation model for the mixing plant outlet. The temperature calculation model for the mixing plant outlet is:

[0068]

[0069] Among them, T 0 T is the outlet temperature of mixing plant; w is the cooling water temperature; T g is the aggregate temperature; T s is the cement temperature; T c is the sand temperature; T f is the fly ash temperature; T ice is the flake ice temperature, take -5℃; G w is the weight of water in concrete; G g is the weight of aggregate in concrete; G s is the weight of cement in concrete; G c is the weight of sand in concrete; G f is the fly ash mass; γ g is the moisture content of aggregate; c is the moisture content of sand; c w is the specific heat of water; c g is the specific heat of aggregate; c s is the specific heat of cement; c c is the specific heat of sand; c f is the specific heat of fly ash; c ice is the specific heat of flake ice; 335 is the latent heat of melting of ice; Q is the mechanical heat generated when concrete is mixed; α is the ice addition rate;

[0070] Since refrigeration measures are usually not taken for cement and fly ash, the average temperature of sand, cement and fly ash is directly collected as its mixing temperature before entering the mixing plant.

[0071] S3. Establish the functional relationship between aggregate temperature, cooling water temperature, ice addition rate and temperature control cost:

[0072] P i =p w (T w -T wi )(1-α i )G w +p g (T g -T gi )G g +p ice α i G w

[0073] Where P i is the temperature control cost; p wThe unit price for cooling 1℃ per kilogram of cooling water; p ice is the unit price per kilogram of flake ice; p g The unit price for cooling 1℃ per kg of aggregate by air cooling; G w is the weight of water in each cubic meter of concrete; G g is the weight of aggregate in each cubic meter of concrete; T w is the initial temperature of cooling water; T g is the initial temperature of aggregate; T wi is the temperature of the cooling water after refrigeration; T gi is the temperature of aggregate after air cooling; α i For ice addition rate.

[0074] S4. In combination with the upper limit and lower limit of the temperature control index determined in S1, according to the mixing plant outlet temperature model in S2, various temperature control index values ​​that meet the outlet target temperature requirements are determined.

[0075] like Figure 2 The specific calculation method is as follows:

[0076] S4.1. Divide the aggregate temperature interval n into equal parts, obtain the aggregate temperature increment Δa, and calculate the aggregate temperature T gi , divide the cooling water temperature interval n into equal parts, obtain the cooling water temperature increment Δb, and calculate the cooling water temperature T wi , divide the ice adding rate interval n into equal parts, obtain the ice adding rate increment Δc, and calculate the ice adding rate α used i , the specific calculation formula is as follows:

[0077]

[0078]

[0079]

[0080] T gi =T g·min +(i-1)Δa i=1,2…n

[0081] T wi =T w·min +(i-1)Δb i=1,2…n

[0082] α i =α min +(i-1)Δc i=1,2…n

[0083] Where Δa is the temperature increment of aggregate; Δb is the temperature increment of cooling water; Δc is the increment of ice addition rate; T g·min is the lower limit of aggregate temperature; T g·max is the upper limit of aggregate temperature; Tw·min is the lower limit of cooling water temperature; T w·max is the upper limit of cooling water temperature, α max is the upper limit of ice adding rate; T gi is the aggregate temperature; T wi is the cooling water temperature; i Ice rate

[0084] S4.2. The aggregate temperature T calculated in step S4.1 is gi , cooling water temperature T wi and ice rate α i Perform permutations and combinations, substitute all permutation and combination data into the mixing plant outlet temperature calculation model in step S2, and calculate the mixing plant outlet temperature.

[0085] When the variables are combined, the outlet temperature of the mixing plant T is calculated. 0 Greater than the allowable outlet temperature T N , less than or equal to the outlet target temperature T M When the aggregate temperature, cooling water temperature and ice addition rate of this group of variable combinations are retained; when the outlet temperature T of the mixing plant calculated after the variable combination 0 Greater than the outlet target temperature T M , then discard the variable combination.

[0086] Allowable outlet temperature T N It is the engineering design value.

[0087] S5. According to the temperature control cost function relationship in step S3, calculate the temperature control costs of all variable combinations that meet the outlet target temperature in step S4.2, and select the variable combination with the smallest temperature control cost as the optimal temperature control index after the outlet temperature is optimized.

[0088] Finally, it should be noted that the above-described embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for optimizing the temperature control index of a large-volume concrete mixing plant outlet, characterized in that: S1. Determine the upper limit value T of aggregate temperature according to the configuration of aggregate air cooling system of mixing plant at the project site. g·max and the lower limit T g·min , according to the configuration of the cooling water system on the project site, determine the upper limit value T of the cooling water temperature w·max and the lower limit T w·min , according to the configuration of the ice making system on the project site, determine the upper limit of the ice adding rate α max ; S2. Establish a temperature calculation model for the mixing plant outlet. The temperature calculation model for the mixing plant outlet is: Where T0 is the outlet temperature of the mixing plant; T w is the cooling water temperature; T g is the aggregate temperature; T s is the cement temperature; T c is the sand temperature; T f is the fly ash temperature; T ice is the flake ice temperature, take -5℃; G w is the weight of water in concrete; G g is the weight of aggregate in concrete; G s is the weight of cement in concrete; G c is the weight of sand in concrete; G f is the fly ash mass; γ g is the moisture content of aggregate; c is the moisture content of sand; c w is the specific heat of water; c g is the specific heat of aggregate; c s is the specific heat of cement; c c is the specific heat of sand; c f is the specific heat of fly ash; c ice is the specific heat of flake ice; 335 is the latent heat of melting of ice; Q is the mechanical heat generated when concrete is mixed; α is the ice addition rate; S3. Establish the functional relationship between aggregate temperature, cooling water temperature, ice addition rate and temperature control cost: P i =p w (T w -T wi )(1-α i )G w +p g (T g -T gi )G g +p ice α i G w Where P i is the temperature control cost; p w The unit price for cooling 1℃ per kilogram of cooling water; p ice is the unit price per kilogram of flake ice; p g The unit price for cooling 1℃ per kg of aggregate by air cooling; G w is the weight of water in each cubic meter of concrete; G g is the weight of aggregate in each cubic meter of concrete; T w is the initial temperature of cooling water; T g is the initial temperature of aggregate; T wi : is the temperature of the cooling water after refrigeration; T gi is the temperature of aggregate after air cooling; α i is the ice addition rate; S4. Substitute the upper limit and lower limit of the temperature control index determined in step S1 into the temperature calculation model of the mixing plant outlet in step S2 to determine the values ​​of various temperature control indexes that meet the outlet target temperature requirements; the specific calculation method is as follows: S4.

1. Divide the aggregate temperature interval n into equal parts, obtain the aggregate temperature increment Δa, and calculate the aggregate temperature T gi , divide the cooling water temperature interval n into equal parts, obtain the cooling water temperature increment Δb, and calculate the cooling water temperature T wi , divide the ice adding rate interval n into equal parts, obtain the ice adding rate increment Δc, and calculate the ice adding rate α used i , the specific calculation formula is as follows: T gi =T g·min +(i-1)Δa i=1,2…n T wi =T w·min +(i-1)Δb i=1,2…n a i =a min +(i-1)Δc i=1,2…n Where Δa is the temperature increment of aggregate; Δb is the temperature increment of cooling water; Δc is the increment of ice addition rate; T g·min is the lower limit of aggregate temperature; T g·max is the upper limit of aggregate temperature; T w·min is the lower limit of cooling water temperature; T w·max is the upper limit of cooling water temperature, α max is the upper limit of ice adding rate; T gi is the aggregate temperature; T wi is the cooling water temperature; i Ice rate; S4.

2. The aggregate temperature T calculated in step S4.1 is gi , cooling water temperature T wi and ice rate α i Perform permutations and combinations, substitute all permutation and combination data into the mixing plant outlet temperature calculation model in step S2, and calculate the mixing plant outlet temperature; When the calculated temperature T0 of the mixing plant outlet after the variable combination is greater than the allowable temperature T N , less than or equal to the outlet target temperature T M When the aggregate temperature, cooling water temperature and ice addition rate values ​​of this group of variable combinations are retained; when the outlet temperature T0 of the mixing plant calculated after the variable combination is greater than the outlet target temperature T M , then discard the variable combination; S5. According to the temperature control cost function relationship in step S3, calculate the temperature control costs of all variable combinations that meet the outlet target temperature in step S4.2, and select the variable combination with the smallest temperature control cost as the optimal temperature control index after the outlet temperature is optimized.

2. The method for optimizing the temperature control index of the outlet of a large-volume concrete mixing plant according to claim 1 is characterized in that: In step S1, the upper limit value T of the aggregate temperature is determined. g·max and the lower limit T g·min The method is: The average temperature of aggregate before it is put into the air cooling bin of the aggregate air cooling system is taken as the upper limit value of aggregate temperature T. g·max ; Determine the rated cooling capacity Q of the air cooling system output according to the configuration of the aggregate air cooling system g , determine the mass of aggregate that needs to be air-cooled per hour based on the mixing strength m g , calculate the maximum temperature drop of aggregate Δt g , determine the lower limit of aggregate temperature T g·min , the specific calculation formula is as follows: T g·min =T g·max -Δt G Where: Δt g is the maximum temperature drop of aggregate; Q g is the rated cooling capacity of the aggregate air cooling system; c g is the specific heat capacity of aggregate; m g The mass of aggregate that needs to be air-cooled per hour; T g·min is the lower limit of aggregate temperature; T g·max is the upper limit of aggregate temperature.

3. The method for optimizing the temperature control index of the outlet of a large-volume concrete mixing plant according to claim 2 is characterized in that: In step S1, the upper limit value T of the cooling water temperature is determined. w·max and the lower limit T w·min The method is: Collect the water temperature of the mixing water tank as the upper limit value T of the cooling water temperature w·max ; Determine the rated cooling capacity Q of the cooling water system according to its configuration w , according to the mixing intensity, determine the mass of cooling water required per hour m w , calculate the maximum cooling amplitude Δt of the cooling water w , determine the lower limit of cooling water temperature T w·min , the specific calculation formula is as follows: T w·min =T w·max -Δt w Where: Δt w is the maximum temperature drop of cooling water; Q w is the rated cooling capacity of the cooling water system; c w is the specific heat capacity of water; m w is the mass of cooling water required per hour; T w·min is the lower limit of cooling water temperature; T w·max It is the upper limit of cooling water temperature.

4. The method for optimizing the temperature control index of the outlet of a large-volume concrete mixing plant according to claim 3 is characterized in that: In step S1, the upper limit value α of the ice adding rate is determined. max The method is: Determine the rated ice making capacity Q of the ice making system according to the configuration of the ice making system on the project site ice , calculate the ice output per hour m ice , and then determine the mass m of cooling water required per hour based on the mixing intensity w , calculate the maximum ice adding rate, that is, the upper limit of ice adding rate α max , the specific calculation formula is as follows: Where: Q ice Rated ice making capacity for ice making system; m ice The amount of ice produced per hour by the ice making system; c w is the specific heat capacity of water; Δt ice is the temperature difference between water and flake ice; 335 is the latent heat of phase change of water from solid to liquid; α max is the upper limit of ice adding rate; m w The mass of cooling water required per hour.

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