Method for measuring apparent reaction heat and specific heat release rate of viscous material reaction system

Abstract

The invention belongs to the field of chemical thermal analysis. The invention discloses a method for measuring apparent reaction heat and specific heat release rate of a viscous material reaction system. According to the measurement method, the full-automatic calorimeter is used for measuring the dilution heat and the reaction heat of the diluted material reaction system, the apparent reaction heat and the specific heat release rate of the viscous material reaction system are obtained through calculation and correction, and the problem that the viscous material reaction system is difficult to measure heat by using the full-automatic calorimeter is solved.

Description

Technical Field

[0001] This invention belongs to the field of chemical thermal analysis. Specifically, it relates to methods for measuring the apparent heat of reaction and specific exothermic rate of chemical reactions. Background Technology

[0002] Determining the apparent heat of reaction and the specific exothermic rate of a chemical reaction is crucial for the study of reaction thermodynamics and kinetics, as well as the design of reactor heat exchange systems.

[0003] For general non-viscous material reaction systems, the apparent heat of reaction and specific heat release rate can be easily obtained using an automatic calorimeter. However, for viscous systems, the automatic calorimeter suffers from poor mixing due to the limitations of the stirring paddle itself, making it impossible to stably control the reaction temperature and resulting in a lower overall heat transfer coefficient. UA Increased error significantly affects the accuracy of reaction calorimetry results, making it impossible to obtain parameters such as apparent reaction heat and specific heat release rate when the actual process can exchange heat normally. Summary of the Invention

[0004] This invention provides a method for measuring the apparent heat of reaction and specific exothermic rate of a viscous material reaction system. This method, by measuring the heat of dilution and the heat of reaction of the diluted material reaction system, and correcting for parameters such as mass, achieves the acquisition of the apparent heat of reaction and specific exothermic rate of the viscous material reaction system.

[0005] This invention provides a method for measuring the apparent heat of reaction and specific exothermic rate of the viscous material reaction system, the specific process of which is as follows:

[0006] 1) Using a Mettler RC1 series automatic calorimeter, a suitable diluent was added to a clean calorimeter. The temperature inside the vessel was controlled to be consistent with the reaction temperature for pre-calibration. The reaction substrate of the viscous material reaction system was then added for post-calibration. The heat of dilution of the reaction substrate was measured, and the influence of the sensible heat of addition caused by the difference between the temperature inside the vessel and the addition temperature was corrected. The heat of mixing of the reaction substrate and diluent in the viscous material reaction system was then calculated. Q 1.

[0007] 2) Control the temperature inside the reactor to be consistent with the reaction temperature. According to the feeding ratio of the viscous material reaction system, add the reactants to the material for which the heat of dilution of the bottom material was measured in the previous step according to the process time, and measure the heat released by the reaction of the diluted material reaction system. Q r,稀 .

[0008] 3) Using general experimental equipment such as flasks, prepare the reaction material according to the actual process of the viscous material reaction system.

[0009] 4) Put the same diluent in proportion into the clean calorimeter, control the temperature in the kettle to be consistent with the reaction temperature, carry out the pre-correction, put the actual process preparation viscous material reaction system reaction material after reaction, carry out the post-correction, measure the dilution heat of the material after reaction, and correct the influence of the sensible heat of feeding, calculate the mixing heat of the viscous material reaction system reaction material after reaction and the diluent Q 2.

[0010] 5) According to the feeding condition and reaction mechanism, the reaction progress of the viscous material reaction system is determined ξ , Q 1 divided by the reaction progress ξ Obtain the dilution enthalpy Δ 1 of the reaction material H 1= -Q 1 / ξ , Q 2 divided by the reaction progress ξ Obtain the dilution enthalpy Δ 2 of the material after reaction H 2= -Q 1 / ξ , Q r,稀 Divided by the reaction progress ξ Obtain the reaction enthalpy change Δ H r,稀 = -Q r,稀 / ξ .

[0011] 6) Using HESS law, the actual apparent reaction enthalpy change Δ H r of the viscous material reaction system is converted H 1+Δ H r,稀 -Δ H 2, that is, the apparent reaction heat of the viscous material reaction system. As long as the reaction material and the material after reaction are measured by adding the same diluent in proportion, the mass and the order of adding the diluent can be inconsistent (determined according to the liquid level requirement of the calorimeter. In order to meet the liquid level requirement of the calorimeter, the reaction material or the material after reaction can be added first to correct, and then the diluent is measured to measure the dilution heat), and the reaction progress corresponding to the measurement of the dilution heat of the feeding can be corrected to the apparent reaction heat of the actual process. When the reaction system is a homogeneous system in the range of room temperature to process temperature, the measurement of the dilution heat of the reaction material and the material after reaction at room temperature can also be carried out to eliminate the error introduced in the correction process of the sensible heat of the feeding.

[0012] 7) The apparent exothermic rate of the dilution material reaction system q r,稀 is obtained, which can be recorded and read by RC1 series calorimeter, or through the heat balance formula q r,稀 = UA [(T r - T j )-( T r - T j ) base ]+ q accu acquisition of T r for reaction temperature, T j ) for jacketed heat conduction oil temperature, T r - T j ) base for calorimetric baseline, q accu for cumulative heat, can refer to Enterprise Standard Q / ZJHA 001-2019 "Method for Determining Isothermal Chemical Reaction MTSR Using Heat Flow Type Reaction Calorimeter".

[0013] 8) Feed heat release rate q dos and feed heat Q dos acquisition, q dos = m dos × C p,dos ×( T in - T r ), (wherein ，m dos is the feed rate, T in is the temperature of the added material, T r is the reaction temperature, C p,dos is the specific heat capacity of the added material at the average temperature T in + T r ) / 2), and the integral of the feed time is Q dos , then the intrinsic reaction heat Δ H r,稀本 of the dilute material reaction system is H r,稀 + Q dos / ξ . Similarly, the intrinsic reaction heat Δ H of the viscous material reaction system isr,本 = Δ H r + Q dos / ξ .

[0014] 9) Known intrinsic heat release rate of dilute material reaction system q r,稀本 = q r,稀- q dos , according to ξ Δ H r,本 = -∫ q r,本 d t and ξ Δ H r,稀本 = -∫ q r,稀本 d t , intrinsic heat release rate of viscous material reaction system q r,本 = Δ H r,本 / Δ H r,稀本 × q r,稀本 , apparent heat release rate of viscous material reaction system q r = q r,本+ q dos = Δ H r,本 / Δ H r,稀本 × q r,稀本+ q dos .

[0015] 10) Known total material mass of viscous material reaction system at a certain moment in the reactor m t = total material mass of dilute material reaction system at a certain moment in the reactor m t,稀 - diluent mass m 稀试剂 , then the specific heat release rate of viscous material reaction system can be obtained q r / m = ( Δ H r,本 / Δ H r,稀本 × ( q r,稀- q dos ) + q dos ( m t,稀 - m 稀试剂 ). DETAILED DESCRIPTION

[0016] The application will be described in more detail below with reference to specific embodiments, but the embodiments of the application are not limited thereto.

[0017] Example 1: 1) Add 150.0 g of diluent water to the RC1 series calorimeter, control the temperature in the kettle to 40.0℃, and perform pre-calibration. Add the viscous material reaction system base material 100.0 g (input the average specific heat capacity of the base material when programming) within 2 min, perform post-calibration, and integrate by software (check the calculation formula) q r Check the calculation formula q dos ) to obtain the dilution heat Q 1=3000.0J.

[0018] 2) Control the temperature in the kettle to 40.0℃, and add the added reactant 50.0 g to the material measured in the previous step according to the feeding ratio of the viscous material reaction system according to the process time 1.0 h. Integrate by software (do not check the calculation formula) q r Do not check the calculation formula q dos ), and measure the heat released by the dilution material reaction system Q r,稀 =50000.0J.

[0019] 3) Use general experimental equipment such as a flask to prepare the post-reaction material according to the actual process (40.0℃, 100.0 g of base material + 50.0 g of added material) of the viscous material reaction system.

[0020] 4) Add 150.0 g of water to the clean calorimeter, control the temperature in the kettle to 40.0℃, and perform pre-calibration. Add 150.0 g of the post-reaction material of the viscous material reaction system prepared according to the actual process within 3 min, perform post-calibration, and integrate by software (check the calculation formula) q r Check the calculation formula q dos ) to obtain the dilution heat Q 2=2500.0J.

[0021] 5) Reaction progress ξ =0.5, Q 1 divided by reaction progress ξThe dilution enthalpy Δ of the reaction mixture is obtained H 1= - 6000.0J, Q 2 divided by the reaction progress ξ The dilution enthalpy Δ of the reaction mixture after the reaction is obtained H 2= -5000.0J, Q r,稀 divided by the reaction progress ξ The reaction enthalpy change Δ of the reaction system of the dilution mixture is obtained H r,稀 - 100000.0J.

[0022] 6) Using the HESS law, the apparent reaction heat Δ H r - 100000.0J - 6000.0J +5000.0J = - 101000.0J.

[0023] 7) According to the calorimetric raw data and the corresponding calculation method, the reaction heat Δ q r,稀

[0024] 8) The average specific heat capacity of the added reaction mixture is 2000.0J / kg / K, and the temperature of the added material is 30.0℃, then Q dos =0.05kg×(2000.0J / kg / K)×(-10.0K)= -1000.0J, q dos =-1000.0J / 3600s=-0.278W.Δ H r,稀本 =Δ H r,稀 + Q dos / ξ - 100000.0J - 1000.0 / 0.5J= -102000.0J,Δ H r,本 =Δ H r + Q dos / ξ - 101000.0J - 1000.0 / 0.5J= -103000.0J.

[0025] 9) Then q ​​​​​r / m = (Δ H r,本 / Δ H r,稀本 ×( q r,稀 - q dos )+ q dos ) / ( m t,稀 - m 稀试剂 ) = (103000.0 / 102000.0×( q r,稀 +0.278)-0.278) / ( m t,稀 -0.15) = (1.010 q r,稀 +0.00278) / ( m t,稀 -0.15)

Claims

1. A method for measuring apparent heat of reaction and specific rate of heat release of a reaction system of a viscous material, characterized in that, The dilution heat and the reaction heat of the dilution material system are measured by using a full-automatic calorimeter, and the apparent reaction heat and the specific heat release rate of the viscous material reaction system are obtained by calculation correction.

2. A method for measuring apparent heat of reaction and specific rate of heat release of a reaction system of a viscous material, characterized by, The full-automatic calorimeter used is a commercial heat flow stirred tank calorimeter, which can be selected but is not limited to the Switzerland Mettler RC1 series full-automatic calorimeter and the Switzerland SYSTAG series full-automatic calorimeter.

3. A method for measuring apparent heat of reaction and specific rate of heat release of a reaction system of a viscous material, characterized by, The background material before diluting the viscous material reaction system with a dilution solvent or post-reaction material (such as not viscous) and the post-reaction material are measured to obtain the heat of the two groups of dilution processes.

4. A method for measuring apparent heat of reaction and specific rate of heat release of a reaction system of a viscous material, characterized by, The diluent selected is an inert reagent, preferably a solvent for diluting the viscous material reaction system itself, and a reagent with similar physical and chemical properties.

5. A method for measuring apparent heat of reaction and specific rate of heat release of a reaction system of a viscous material, characterized by, After the reaction heat of the dilution material system, the apparent reaction heat and the specific heat release rate of the viscous material reaction system are obtained by correction of mass and other parameters.