A method and device for testing continuous flow reaction heat using reference calorimetry

Abstract

The present invention relates to the test of reaction heat in a continuous flow reaction process, and specifically to a method and device for testing the reaction heat of a continuous flow using reference calorimetry. Raw materials are continuously added to a sample reactor and a reference reactor at the same flow rate at the same time, and the reaction residence time is controlled by the speed of adding materials and the system pressure. The reference calorimetry is used to collect the deviation of the system voltage signal from the baseline value △U in the reaction process in real time through a constant temperature mode or a scanning mode; the reaction heat release rate q and the heat absorption and release Q of the reaction process when the heat flow of the reaction system is stable are calculated according to the deviation of the real-time voltage signal from the baseline value △U. r ; Then calculate the apparent heat of reaction △H by the heat absorption and release of the reaction process m The present invention is provided with a reference and a sample reactor. During the reaction process, materials are fed into the reference and sample reactors simultaneously, and the flow rates on both sides are controlled. While the reaction is completed, the influence of the sensible heat of material addition and the latent heat of vaporization are directly deducted to avoid the endothermic heat of vaporization or the sensible heat of addition covering the exothermic signal, and obtain the real heat change of the reaction.

Description

Technical Field

[0001] The invention relates to a test of reaction heat in a continuous flow reaction process, in particular to a method and a device for testing the reaction heat of a continuous flow by using reference calorimetry. Background Art

[0002] Apparent heat of reaction is a comprehensive expression of the energy released or absorbed during a chemical reaction. It is an important parameter required for chemical design and safe production. At present, the reaction calorimetry test instruments that have been industrialized on the market mainly include reaction calorimeters (RC1 / Simular), accelerating calorimeters (ARC) and differential scanning calorimeters (DSC). The above equipment are laboratory-scale devices, mainly for reaction heat testing of batch and semi-batch processes. For example, the typical literature "Thermal Safety Study of Ethyl Butyrate Synthesis Process" uses RC1 to conduct calorimetric tests on ethyl butyrate synthesis. In the test process, n-butanol is used as the base material, and acetic anhydride is added dropwise to complete the calorimetric test. The reaction is a liquid-liquid homogeneous reaction. Another typical literature "Thermal Safety Study of Ethyl Butyrate Synthesis Process" uses RC1 to conduct calorimetric tests on ethyl butyrate synthesis. In the test process, n-butanol is used as the base material, and acetic anhydride is added dropwise to complete the calorimetric test. The reaction is a liquid-liquid homogeneous reaction. The literature is "Thermodynamic study of acetic anhydride alcoholysis reaction and calculation of safe discharge size", RC1 and ARC were used to study the thermal characteristics of acetic anhydride alcoholysis reaction, and the heat release characteristics of the reaction heat in the acetic anhydride alcoholysis process were studied. The reaction is also a liquid-liquid homogeneous reaction. In the RC1 test process, methanol is added to acetic anhydride to complete the calorimetric test. In the ARC test process, methanol and acetic anhydride are kept at low temperatures, and the test cell is quickly installed in the test system to complete the reaction calorimetry. However, the reaction calorimeters mentioned above cannot achieve continuous flow process reaction heat testing with continuous discharging and continuous feeding. Summary of the invention

[0003] The present invention aims to provide a method and device for testing the heat of continuous flow reaction using reference calorimetry

[0004] To achieve the above purpose, the present invention adopts the following technical solution:

[0005] A device for testing continuous flow reaction heat by reference calorimetry comprises a reference inlet and outlet system A, a sample inlet and outlet system B, a reactor system and a central control system, wherein the reactor system is provided with a sample reactor and a reference reactor, the reference inlet and outlet system A comprises a liquid raw material bottle A, a gas raw material bottle A, a mixer A, a sampler A and a gas-liquid separator A, wherein the liquid raw material bottle A and the gas raw material bottle A are respectively connected to the mixer A, the mixer A, the reference reactor, the sampler A and the gas-liquid separator A are sequentially connected in series, the sample inlet and outlet system B comprises a liquid raw material bottle B, a gas raw material bottle B, the mixer B, the sampler B and the gas-liquid separator B, wherein the liquid raw material bottle B and the gas raw material bottle B are respectively connected to the mixer A, A sample reactor is connected to a sampler B, and a mixer B, a sample reactor, a sampler B and a gas-liquid separator B are connected in series in sequence; a precision liquid feeding pump is provided between the liquid raw material bottle A and the mixer A, and between the liquid raw material bottle B and the mixer B, a gas flow meter is provided between the gas raw material bottle A and the mixer A, and between the gas raw material bottle B and the mixer B, an electromagnetic valve is provided between the reference reactor and the sampler A, and between the sample reactor and the sampler B, a pressure sensor, a temperature sensor and a voltage signal sensor are provided on the sample reactor and the reference reactor, and the precision liquid feeding pump, the gas flow meter, the electromagnetic valve, the pressure sensor, the temperature sensor and the voltage signal sensor are all connected to the central control system.

[0006] The first pipeline A between the liquid raw material bottle A and the mixer A is provided with a first ball valve A, a first check valve A, a precision liquid feeding pump A and a second check valve A in sequence along the transmission direction.

[0007] The second pipeline A between the gas raw material bottle A and the mixer A is provided with a first pressure gauge A, a needle valve A, a second ball valve A, a third one-way valve A, a gas flow meter A and a fourth one-way valve A in sequence along the transmission direction.

[0008] A one-way valve A is provided on the third pipeline A between the mixer A and the reference reactor.

[0009] A solenoid valve A and a second pressure gauge A are sequentially arranged on the fourth pipeline A between the reference reactor and the sampler A along the transmission direction.

[0010] The first pipeline B between the liquid raw material bottle B and the mixer B is provided with a first ball valve B, a first check valve B, a precision liquid feeding pump B and a second check valve B in sequence along the transmission direction.

[0011] The second pipeline B between the gas raw material bottle B and the mixer B is provided with a first pressure gauge B, a needle valve B, a second ball valve B, a third one-way valve B, a gas flow meter B and a fourth one-way valve B in sequence along the transmission direction.

[0012] A one-way valve B is provided on the third pipeline B between the mixer B and the sample reactor.

[0013] A solenoid valve B and a second pressure gauge B are sequentially arranged on the fourth pipeline B between the sample reactor and the sampler B along the transmission direction.

[0014] A method for testing the heat of a continuous flow reaction by using a reference calorimetry device for testing the heat of a continuous flow reaction, wherein raw materials are continuously added to a sample reactor and a reference reactor at the same flow rate at the same time, the reaction residence time is controlled by the speed of adding materials and the system pressure, and the reference calorimetry is used to collect the deviation of the system voltage signal from the baseline value △U in the reaction process in real time through a constant temperature mode or a scanning mode; the reaction heat release rate q (in mW) when the heat flow of the reaction system is stable and the heat absorption and release Q of the reaction process are calculated according to the deviation of the real-time voltage signal from the baseline value △U (in μV) r (unit is J); then calculate the apparent reaction heat △H by the heat absorption and release of the reaction process m .

[0015] Further,

[0016] 1) Calibration, by pulse length and interval, a pulse signal of fixed time is emitted at a fixed interval, and a cycle test is performed within the target temperature range to obtain the sensitivity through the Joule effect (pulse signal) (Formula (1));

[0017]

[0018] In the formula, a i is the different cycle sensitivities at different temperatures (in μV·mW -1 ), i is the number of cycles, Q i is the voltage peak area obtained for each pulse (in μV·s), T is the temperature (in K), P is the power (in mW), and t is the time (in s);

[0019] The sensitivity of the reciprocating cycle at different temperatures is fitted to obtain the relationship between temperature T and sensitivity a. i The polynomial (Formula (2)) and the multi-level sensitivity coefficient b are obtained n ,n is a natural number starting from 0;

[0020] a i (T) = b 0 +b 1 T+b 2 T 2 +b 3 T 3 +b 4 T 4 +…… (2)

[0021] Where T is temperature (in K);

[0022] 2) Loading: Load solid or liquid reaction raw materials into the sample reactor and fix it at the reactor outlet. The bed thickness of catalyst and other materials can be designed according to process requirements. Heat up at a constant rate or to the target temperature, and wait for the system voltage signal baseline to stabilize.

[0023] 3) Feeding: Add raw materials to the sample and reference reactors simultaneously and continuously, and control the material flow rates on both sides to be completely consistent. Control the reaction residence time by the feeding speed and system pressure, and collect the deviation of the system voltage signal from the baseline value △U in real time online during the reaction process.

[0024] 4) When the reaction system is stable, stop feeding the sample and reference reactors. The feeding time is t 0 , obtain the feed mass W (in g), t 0 The voltage signal deviation from the baseline value is integrated within the time period (Formula (3)), and the peak area S is:

[0025]

[0026] Where S is the integrated peak area (in μV·s), and P is the power (in mW)

[0027] Calculate the heat absorption and release Q of the reaction process according to the sensitivity a(T) at different temperatures t0 (Formula (4))

[0028]

[0029] In the formula, Q t0 is the amount of heat absorbed and released (in J)

[0030] The conversion relationship between the number of moles of reactants and the mass of reactants is as follows:

[0031]

[0032] m 0 t 0 The number of moles of a reactant added in a time period (in mol); W is t 0 The mass of a reactant added during a period of time (in g); M is the molar molecular weight of a reactant added (in g·mol -1 )

[0033] The apparent molar heat of reaction △H m for:

[0034]

[0035] In the formula, △H mis the apparent molar heat of reaction (based on the number of moles of a reactant) (in kJ·mol -1 ).

[0036] The reaction temperature ranges from room temperature to 600°C, the pressure is 0-400 bar, and the heating rate is 0-2 K·min -1 The injection gas flow rate is 0.05-1000mL·min -1 , injection liquid flow rate is 0.001-200mL·min -1 .

[0037] Going further,

[0038] 1) Calibration: To obtain accurate heat flow values, a sensitivity test is required. The sensitivity changes with temperature.

[0039] Before testing, set the pulse length and interval according to the instrument's instructions, emit a series of fixed-time pulse signals at fixed intervals, and perform cyclic testing within the target temperature range.

[0040] At a given power P (in mW) within a time t, wait for the voltage signal to return to the initial baseline, and perform an integral on the voltage peak area obtained for each pulse to obtain the integral value Q i (unit: μV·s), Q i (in μV·s) divided by the product of power P (in mW) and time t (in s), which defines the heat given by the Joule effect, gives the sensitivity coefficient a (in μV·mW -1 )Right now:

[0041]

[0042] In the formula, a i is the different cycle sensitivities at different temperatures (in μV·mW -1 ), i is the number of cycles, Q i is the voltage peak area integration of each pulse (in μV·s), T is the temperature (in K), P is the power (in mW), and t is the time (in s)

[0043] The sensitivity of the reciprocating cycle at different temperatures is fitted to obtain the relationship between temperature T and sensitivity a. i The polynomial (Formula (2)) and the multi-level sensitivity coefficient b are obtained n , n is a natural number starting from 0.

[0044] a i (T) = b 0 +b 1 T+b 2 T2 +b 3 T 3 +b 4 T 4 +…… (2)

[0045] Where T is temperature (in K);

[0046] 2) Loading: Load solid or liquid reaction raw materials into the sample reactor and fix it at the reactor outlet. The bed thickness of catalyst and other materials can be designed according to process requirements. Heat up at a constant rate or to the target temperature, and wait for the system voltage signal baseline to stabilize.

[0047] 3) Feeding: Add raw materials to the sample and reference reactors simultaneously and continuously, and control the material flow rates on both sides to be completely consistent. Control the reaction residence time by the feeding speed and system pressure, and collect the deviation of the system voltage signal from the baseline value △U in real time online during the reaction process.

[0048] 4) When the reaction system is stable, stop feeding the sample and reference reactors. The feeding time is t 0 , obtain the feed mass W (in g), t 0 The voltage signal deviation from the baseline value is integrated within the time period (Formula (2)), and the peak area S is:

[0049]

[0050] Where S is the integrated peak area (in μV·s), and P is the power (in mW)

[0051] Calculate the heat absorption and release Q of the reaction process according to the sensitivity a(T) at different temperatures t0 (Formula (4))

[0052]

[0053] In the formula, Q t0 is the amount of heat absorbed and released (in J)

[0054] The conversion relationship between the number of moles of reactants and the mass of reactants is as follows:

[0055]

[0056] m 0 t 0 The number of moles of a reactant added in a time period (in mol); W is t 0 The mass of a reactant added during a period of time (in g); M is the molar molecular weight of a reactant added (in g·mol -1 )

[0057] The apparent molar heat of reaction △H m for:

[0058]

[0059] In the formula, △H m is the apparent molar heat of reaction (based on the number of moles of a reactant) (in kJ·mol -1 ).

[0060] The reactions are calorimetric tests of gas-solid, gas-liquid and liquid-liquid phase continuous reactions.

[0061] The advantages of the present invention are:

[0062] 1. The device of the present invention is provided with a reference reactor and a sample reactor at the same time. During the reaction process, liquid or gas is introduced into the reference reactor and the sample reactor at the same time, and the flow rates on both sides can be strictly controlled. While completing the reaction, the influence of the sensible heat of material addition and the latent heat of vaporization can be directly deducted to avoid the endothermic heat of vaporization or the sensible heat of addition covering the exothermic signal, and obtain the real heat change of the reaction.

[0063] 2. The device of the present invention can implement precise control of the gas-solid, gas-liquid and liquid-liquid phase continuous flow reaction process according to the constant temperature and scanning temperature rise mode, and real-time online data acquisition and data analysis. Among them, the reactor system is provided with a sample and reference test cell, and a three-dimensional multi-symmetric PT100 temperature sensor is provided around the sample and reference cell, which can obtain more accurate heat release heat change and can also accurately control the temperature of the reactor. A pressure sensor is provided at the input end of the sample and reference reactor to detect the reactor pressure in real time, and a pressure valve and a gas mass flow meter are connected to the gas feed pipeline, and an electromagnetic valve is provided at the output end, and the gas flow rate, reaction pressure and reaction material residence time can be accurately controlled by the PID control system. In addition, the sample and reference reactor input ends are connected to a precise liquid feed pump, and the liquid flow rate, reaction pressure and reaction residence time can be accurately controlled by the PID control system.

[0064] The central control system of the above-mentioned device is a single-chip microcomputer, PLC, intelligent instrument, and central control system with built-in switch control, proportional action, integral action, differential action and even PID algorithm. It can convert and display the collected signals and output control signals according to feedback signals. It can also realize the collection, processing and display of temperature and pressure signals, and adjust the behavior of the temperature control unit and the pressure control unit in real time according to the feedback signals.

[0065] 3. The device of the present invention is used to measure the reaction heat of gas-solid and gas-liquid continuous flow reaction processes and the data such as the heat release rate and heat absorption rate in the continuous flow reaction process by constant temperature heat flow or scanning, and the control system is used to control the calculation, so that the heat release and heat absorption continuous flow reaction calorimetric test can be realized according to the continuous flow reaction process conditions.

[0066] 4. The apparent results obtained by the continuous flow reaction calorimetry experimental test method of the present invention can play a more practical and effective guiding role in the engineering design, process safety and process optimization involved in realizing energy conversion and transfer. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 A schematic diagram of a structure provided by an embodiment of the present invention,

[0068] Figure 2 The sensitivity at different temperatures provided in the embodiment of the present invention is fitted into a curve.

[0069] Figure 3 A schematic diagram of voltage changes during a reaction process provided by an embodiment of the present invention.

[0070] Wherein, A is a reference test system, 11 is a liquid raw material bottle A, 12 is a first ball valve A, 13 is a first non-return valve A, 14 is a precision liquid feed pump A, 15 is a second non-return valve A, 16 is a gas raw material bottle A, 17 is a first pressure gauge A, 18 is a needle valve A, 19 is a second ball valve A, 110 is a third non-return valve A, 111 is a gas flow meter A, 112 is a fourth non-return valve A, 113 is a mixer A, 114 is a non-return valve A, 115 is a solenoid valve A, 116 is a three-way valve A, 117 is a gas-liquid separator A, 118 is a sampler A, 119 is a second pressure gauge A, 120 is a first pipeline A, 121 is a second pipeline A, 122 is a third pipeline A, and 123 is a fourth pipeline A;

[0071] B is a reference test system, 21 is a liquid raw material bottle B, 22 is a first ball valve B, 23 is a first non-return valve B, 24 is a precision liquid feed pump B, 25 is a second non-return valve B, 26 is a gas raw material bottle B, 27 is a first pressure gauge B, 28 is a needle valve B, 29 is a second ball valve B, 210 is a third non-return valve B, 211 is a gas flow meter B, 212 is a fourth non-return valve B, 213 is a mixer B, 214 is a non-return valve B, 215 is a solenoid valve B, 216 is a three-way valve B, 217 is a gas-liquid separator B, 218 is a sampler B, 219 is a second pressure gauge B, 220 is a first pipeline B, 221 is a second pipeline B, 222 is a third pipeline B, 223 is a fourth pipeline B, and 224 is an online analyzer;

[0072] 31 is a reaction furnace, 32 is a sample reactor, and 33 is a reference reactor. DETAILED DESCRIPTION

[0073] The present invention will be further described below by way of examples, but are not limited thereto.

[0074] The method and device of the present invention utilize the reference calorimetry principle to realize reaction heat testing of continuous processes such as gas-solid, gas-liquid and liquid-liquid, and add a reference material similar to the reactor material to eliminate the thermodynamic effect of the reactor itself during the reaction process. In addition, by adding solid or liquid fixing devices, flow control and pressure control systems, the reaction heat testing requirements under different working conditions can be met to obtain more accurate reaction heat data.

[0075] Example 1

[0076] like Figure 1As shown, the method includes a reference inlet and outlet system A, a sample inlet and outlet system B, a reactor system and a central control system, wherein the reactor system includes a reaction furnace 31, a sample reactor 32 and a reference reactor 33, the sample reactor 32 and the reference reactor 33 are both arranged in the reaction furnace 31, the reference inlet and outlet system A and the sample inlet and outlet system B are two parallel systems, wherein the reference inlet and outlet system A includes a liquid raw material bottle A11, a gas raw material bottle A16, a mixer A113, The sampler A118 and the gas-liquid separator A117, the liquid raw material bottle A11 and the gas raw material bottle A16 are respectively connected to the mixer A113 through pipelines, the mixer A113, the reference reactor 33, the sampler A118 and the gas-liquid separator A117 are connected in series in sequence, and the sample inlet and outlet system B includes a liquid raw material bottle B21, a gas raw material bottle B26, a mixer B213, a sampler B218 and a gas-liquid separator B217, the liquid raw material bottle B21 and The gas raw material bottle B26 is connected to the mixer B213 through pipelines, and the mixer B213, the sample reactor 32, the sampler B218 and the gas-liquid separator B217 are connected in series in sequence; a precision liquid feeding pump is provided on the pipeline between the liquid raw material bottle A11 and the mixer A113 and on the pipeline between the liquid raw material bottle B21 and the mixer B213, a gas flow meter is provided on the pipeline between the gas raw material bottle A16 and the mixer A113 and on the pipeline between the gas raw material bottle B26 and the mixer B213, an electromagnetic valve is provided on the pipeline between the reference reactor 33 and the sampler A118 and on the pipeline between the sample reactor 32 and the sampler B218, and a pressure sensor, a temperature sensor and a voltage signal sensor are provided on the sample reactor 32 and the reference reactor 33, and the precision liquid feeding pump, the gas flow meter, the electromagnetic valve, the pressure sensor, the temperature sensor and the voltage signal sensor are all connected to the central control system. The mixer, reactor, sampler, gas-liquid separator and reaction furnace 31 are all well-known in the art and are commercially available products, wherein the reaction furnace 31 is provided with a heating system.

[0077] like Figure 1As shown, the first pipeline A120 between the liquid raw material bottle A11 and the mixer A113 is provided with a first ball valve A12, a first check valve A13, a precision liquid feeding pump A14 and a second check valve A15 in sequence along the transmission direction, and the second pipeline A121 between the gas raw material bottle A16 and the mixer A113 is provided with a first pressure gauge A17, a needle valve A18, a second ball valve A19, a third check valve A110, a gas flow meter A111 and a first pressure gauge A17, a needle valve A18, a second ball valve A19, a third check valve A110, a gas flow meter A111 and a first check valve A111 in sequence along the transmission direction. A one-way valve A112 is provided on the third pipeline A122 between the mixer A113 and the reference reactor 33, a solenoid valve A115 and a second pressure gauge A119 are provided in sequence along the transmission direction on the fourth pipeline A123 between the reference reactor 33 and the sampler A118, a three-way valve A116 is provided on the pipeline between the sampler A118 and the gas-liquid separator A117, and the three-way valve A116 is connected to the online analyzer 224 through a line.

[0078] like Figure 1 As shown, the first pipeline B220 between the liquid raw material bottle B21 and the mixer B213 is provided with a first ball valve B22, a first check valve B23, a precision liquid feeding pump B24 and a second check valve B25 in sequence along the transmission direction, and the second pipeline B221 between the gas raw material bottle B26 and the mixer B213 is provided with a first pressure gauge B27, a needle valve B28, a second ball valve B29, a third check valve B210, a gas flow meter B211 and a first pressure gauge B27, a needle valve B28, a second ball valve B29, a third check valve B210, a gas flow meter B211 and a first check valve B25 in sequence along the transmission direction. A one-way valve B214 is provided on the third pipeline B222 between the mixer B213 and the sample reactor 32, a solenoid valve B215 and a second pressure gauge B219 are provided in sequence along the transmission direction on the fourth pipeline B223 between the sample reactor 32 and the sampler B218, a three-way valve B216 is provided on the pipeline between the sampler B218 and the gas-liquid separator B217, and the three-way valve B216 is connected to the online analyzer 224 through a line.

[0079] Check valves are provided on the input and output pipelines of the gas flow meter A111 and the input and output pipelines of the gas flow meter B211. In addition, pressure reducing valves are provided on the pipelines between the liquid raw material bottle A11 and the first ball valve A12 and the pipelines between the liquid raw material bottle B21 and the first ball valve B22, and feed pressure sensors are provided on the input and output pipelines of the pressure reducing valves. The ball valve, check valve, precision liquid feed pump, pressure gauge, needle valve, gas flow meter, solenoid valve, three-way valve and online analyzer are all well-known technologies in the art and are commercially available products.

[0080] In this embodiment, the sample reactor 32 and the reference reactor 33 are both provided with a reaction pool, and a three-dimensional multi-symmetric PT100 temperature sensor is provided around the reaction pool, which can obtain more accurate heat release changes and accurately control the temperature of the reactor. Pressure sensors are provided at the input end of the sample reactor 32 and the input end of the reference reactor 33 to detect the reactor pressure in real time, and gas flow meters are provided on the gas feed pipelines of the reference inlet and outlet system A and the sample inlet and outlet system B. Solenoid valves are provided on the output pipelines of the sample reactor 32 and the reference reactor 33. The central control system can accurately control the gas flow rate, reaction pressure and reaction material residence time. In addition, the reference inlet and outlet system A and the sample inlet and outlet system B are provided with precision liquid feeding pumps, and the liquid flow rate, reaction pressure and reaction residence time can be accurately controlled by the central control system.

[0081] In this embodiment, the central control system is a PID control system, which has a single-chip microcomputer with various switch controls and PID algorithms embedded therein, can convert and display the collected signals, and can control the signal output according to the feedback signal, can realize the collection, processing and display of temperature and pressure signals, and adjust the temperature and pressure in real time according to the feedback signal. The central control system is a well-known technology in the art.

[0082] Example 2

[0083] In this embodiment, 30% methanol aqueous solution was used in a solid catalyst (the catalyst mainly comprises CuO, ZnO, Al 2 O 3 、Na 2 O) catalytic cracking reaction to generate hydrogen and carbon dioxide is used as an example to illustrate the calorimetric test method of the present invention, and further verified by bond energy calculation. 30% methanol aqueous solution at 0.0011g·s -1 The flow rate enters, the reaction temperature is set to 250-350℃, the material residence time is 15-20s, and the reaction pressure is 1.0Mpa.

[0084] Test steps:

[0085] 1) Calibration. Within 2100s, the power is given at 10mW, each cycle time is 5400s, and the return of the calorimetric signal is waited at the initial baseline. The voltage peak area obtained for each pulse is integrated, and the area is Q i , the calibration temperature range is 150-450℃.

[0086] Each pulse time t = 2100s

[0087] Each pulse given power P = 10mW

[0088] According to formula 1, the sensitivity a under different temperatures and cycles is obtained i , the sensitivity at different temperatures is fitted (see Figure 2 ), according to the fitting curve, the sensitivity coefficients are:

[0089] b 1 =+5.543711E+0

[0090] b 2 =+4.186064E-3

[0091] b 3 =-3.4424099E-5

[0092] b 4 =+5.288008E-8

[0093] b 5 =-3.001592E-11

[0094] 2) 150-450℃ sensitivity a i (T) The polynomial is:

[0095] a i (T)=(5.543711E+0)+(4.186064E-3)T+(-3.4424099E-5)T 2 +(5.288008E-8)T 3 +(-3.001592E-11)T 4

[0096] 3) Air tightness test of reaction system. Nitrogen is introduced into the sample and reference reaction systems through the feeding system, and the nitrogen pressure is controlled by the pressure reducing gauge. When the nitrogen reaches 3.0 MPa, the nitrogen is stopped and the pressure test is carried out. If the pressure drop of the reactor system is less than 0.01 within 1 hour,

[0097] bar·min -1 When , the reaction system can be considered to be airtight and the pressure maintenance is completed.

[0098] 4) Pressure relief: Open the solenoid valve and release the pressure to 0.1MPa.

[0099] 5) Add 3.5 g of solid catalyst to the sample reactor. The catalyst filling amount is 90-95% of the total volume of the test cell. After the addition is completed, connect the sample reactor to the reactor system.

[0100] 6) Start the reactor heating system. Set to 2K·min -1 Raise the temperature to 300°C and keep constant.

[0101] 7) Feeding. When the temperature in the reactor heating furnace is stable, the reference liquid feeding pump A14 and the sample liquid feeding pump B24 are fed at a rate of 0.0011 g·s -1 30% methanol aqueous solution is pumped into the sample reactor and the reference reactor at the same flow rate. The methanol in the sample system reacts under the action of the solid catalyst in the sample reactor, and the methanol in the reference system passes through the reference cell and is discharged.

[0102] 8) Data acquisition. The temperature sensor and voltage signal sensor are used to collect the changes of furnace temperature and voltage signal in the reactor in real time (see Figure 3 ), and read the voltage signal deviation from the baseline value △U, and collect the system pressure changes through the pressure sensor. All data are collected in real time through the central control system, and the experimental phenomena are recorded until the end of the experiment.

[0103] 9) After the experiment, clean and purge the reactor system.

[0104] 10) Integrate the voltage signal deviation from the baseline value △U, and the area is S (in mV·s)

[0105] 11)t 0 =3.2h=11520s;

[0106] 12) S = 2.03492E + 07 μV·s

[0107] 13) Sensitivity a i (T=300℃)=3.351779μW·mW -1

[0108] 14) Substitute all values ​​into formula (4) and calculate the heat released during the reaction process Q t0 6.07116KJ

[0109] 15) The mass flow rate of 30% methanol aqueous solution is 0.0011 g·s -1 The apparent molar heat of reaction of this reaction process is based on methanol.

[0110] 16) W = 3.8016 g

[0111] 17) M = 32.04 g·mol -1

[0112] 18) According to formula (4), the molar amount of methanol is n 0 0.1187mol

[0113] 19) The molar heat of reaction of methanol to hydrogen is -51.1 kJ·mol -1 (Based on moles of methanol) (excluding latent heat of vaporization and sensible heat of addition).

[0114] 20) Result verification. According to the literature, the molar heat of reaction of methanol to hydrogen is -49.5 kJ·mol -1 (based on the moles of methanol), the error between the reaction heat obtained by this method and the value reported in the literature is 3.5%, which does not exceed 5%.

[0115] In the above embodiment, 30% methanol aqueous solution was used in a solid catalyst (the catalyst main components are CuO, ZnO, Al 2 O 3 、Na 2 O) catalytic cracking reaction to generate hydrogen and carbon dioxide is used as an example to verify the device and the test method of the present invention. The apparent reaction heat obtained by the method of testing the continuous flow reaction heat using reference calorimetry of the present invention is reasonable and credible; furthermore, it can be applied to various calorimetric tests of tubular reaction gas-solid and gas-liquid phase continuous flow reactions obtained by constant temperature or scanning temperature rising mode.

Claims

1. A method for testing continuous flow reaction heat using a reference calorimeter to test continuous flow reaction heat, characterized in that: The raw materials are continuously added to the sample reactor and the reference reactor at the same flow rate, and the reaction residence time is controlled by the speed of adding materials and the system pressure. The reference calorimeter is used to collect the deviation of the system voltage signal from the baseline value △U in real time during the reaction process in a constant temperature mode or a scanning mode; the reaction heat release rate q (in mW) when the heat flow of the reaction system is stable and the heat absorption and release Q of the reaction process are calculated based on the deviation of the real-time voltage signal from the baseline value △U (in μV) r (unit is J); then calculate the apparent reaction heat △H by the heat absorption and release of the reaction process m ; Specifically: 1) Calibration, by pulse length and interval, a pulse signal of fixed time is emitted at a fixed interval, and a cycle test is performed within the target temperature range to obtain the sensitivity through the Joule effect (pulse signal) (Formula (1)); In the formula, a i is the different cycle sensitivity at different temperatures (in μV·mW -1 ), i is the number of cycles, Q i is the voltage peak area obtained for each pulse (in μV·s), T is the temperature (in K), P is the power (in mW), and t is the time (in s); The sensitivity of the reciprocating cycle at different temperatures is fitted to obtain the relationship between temperature T and sensitivity a. i The polynomial (Formula (2)) and the multi-level sensitivity coefficient b are obtained n ,n is a natural number starting from 0; <h2 style=";text-align:left;direction:ltr">a<h2 style=";text-align:left;direction:ltr"> i <h2 style=";text-align:left;direction:ltr"> (T) = b0 + b1T + b2T<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +b3T<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> +b4T<h2 style=";text-align:left;direction:ltr"> 4 <h2 style=";text-align:left;direction:ltr"> +…… (2) Where T is temperature (in K); 2) Loading: Load solid or liquid reaction materials into the sample reactor and fix it at the reactor outlet. Design the bed thickness of catalyst and other materials according to process requirements, heat up at a constant rate or to the target temperature, and wait for the system voltage signal baseline to stabilize; 3) Feeding: adding raw materials to the sample and reference reactors simultaneously and continuously, and controlling the material flow rates on both sides to be completely consistent, controlling the reaction residence time by the feeding speed and system pressure, and collecting the deviation of the system voltage signal from the baseline value △U during the reaction process in real time online; 4) When the reaction system is stable, stop feeding the sample and reference reactors. At this time, the feeding time is t0. Obtain the feed mass W (in g). Integrate the voltage signal deviation from the baseline value during the t0 period (Formula (3)). The peak area S is: Where S is the integrated peak area (in μV·s), P is the power (in mW). The endothermic and exothermic heat Q of the reaction process is calculated based on the sensitivity a(T) at different temperatures. t0 (Formula (4)) In the formula, Q t0 is the amount of heat absorbed and released (in J) The conversion relationship between the number of moles of reactants and the mass of reactants is as follows: m0 is the number of moles of a reactant added during the time period t0 (in mol); W is the mass of a reactant added during the time period t0 (in g); M is the molar molecular weight of a reactant added (in g·mol -1 ) The apparent molar heat of reaction △H m for: In the formula, △H m is the apparent molar heat of reaction (based on the number of moles of a reactant) (in kJ·mol -1 ); The device for testing the heat of a continuous flow reaction by using reference calorimetry comprises a reference feeding and discharging system A, a sample feeding and discharging system B, a reactor system and a central control system. The reactor system is provided with a sample reactor (32) and a reference reactor (33). The reference feeding and discharging system A comprises a liquid raw material bottle A (11), a gas raw material bottle A (16), a mixer A (113), a sampler A (118) and a gas-liquid separator A (117). The liquid raw material bottle A (11) and the gas raw material bottle A (16) are respectively connected to the mixer A (113). The mixer A (113), the reference reactor (33), the sampler A (118) and the gas-liquid separator A (117) are sequentially connected in series. The sample feeding and discharging system B comprises a liquid raw material bottle B (21), a gas raw material bottle B (26), a mixer B (213), a sampler B (218) and a gas-liquid separator B (217). The liquid raw material bottle B (21) and the gas raw material bottle B (26) are respectively connected to the mixer A (113). The mixer A (113), the reference reactor (33), the sampler A (118) and the gas-liquid separator A (117) are sequentially connected in series. The liquid raw material bottle A (11) and the mixer A (113) are connected to each other respectively; the mixer B (213), the sample reactor (32), the sampler B (218) and the gas-liquid separator B (217) are connected in series in sequence; a precision liquid feeding pump is provided between the liquid raw material bottle A (11) and the mixer A (113) and between the liquid raw material bottle B (21) and the mixer B (213); a gas flow meter is provided between the gas raw material bottle A (16) and the mixer A (113) and between the gas raw material bottle B (26) and the mixer B (213); an electromagnetic valve is provided between the reference reactor (33) and the sampler A (118) and between the sample reactor (32) and the sampler B (218); a pressure sensor, a temperature sensor and a voltage signal sensor are provided on the sample reactor (32) and the reference reactor (33); and the precision liquid feeding pump, the gas flow meter, the electromagnetic valve, the pressure sensor, the temperature sensor and the voltage signal sensor are all connected to the central control system.

2. The method for testing the heat of a continuous flow reaction using a reference calorimeter for testing the heat of a continuous flow reaction according to claim 1, characterized in that: The target temperature is from room temperature to 600°C, the pressure is 0-400 bar, and the heating rate is 0-2K·min -1 The injection gas flow rate is 0.05-1000mL·min -1 , injection liquid flow rate is 0.001-200mL·min -1 .

3. The method for testing the heat of a continuous flow reaction by using a reference calorimeter to test the heat of a continuous flow reaction according to claim 1, characterized in that: A first ball valve A (12), a first check valve A (13), a precision liquid feed pump A (14) and a second check valve A (15) are sequentially provided on the first pipeline A (120) between the liquid raw material bottle A (11) and the mixer A (113) along the transmission direction; a first ball valve B (22), a first check valve B (23), a precision liquid feed pump B (24) and a second check valve B (25) are sequentially provided on the first pipeline B (220) between the liquid raw material bottle B (21) and the mixer B (213) along the transmission direction.

4. The method for testing the heat of a continuous flow reaction using a reference calorimeter to test the heat of a continuous flow reaction according to claim 1, characterized in that: A first pressure gauge A (17), a needle valve A (18), a second ball valve A (19), a third check valve A (110), a gas flow meter A (111) and a fourth check valve A (112) are provided in sequence along the transmission direction on the second pipeline A (121) between the gas raw material bottle A (16) and the mixer A (113); a first pressure gauge B (27), a needle valve B (28), a second ball valve B (29), a third check valve B (210), a gas flow meter B (211) and a fourth check valve B (212) are provided in sequence along the transmission direction on the second pipeline B (221) between the gas raw material bottle B (26) and the mixer B (213).

5. The method for testing continuous flow reaction heat using a reference calorimeter to test continuous flow reaction heat according to claim 1, characterized in that: A one-way valve A (114) is provided on the third pipeline A (122) between the mixer A (113) and the reference reactor (33); a one-way valve B (214) is provided on the third pipeline B (222) between the mixer B (213) and the sample reactor (32).

6. The method for testing continuous flow reaction heat using a reference calorimeter to test continuous flow reaction heat according to claim 1, characterized in that: A solenoid valve A (115) and a second pressure gauge A (119) are provided in sequence on the fourth pipeline A (123) between the reference reactor (33) and the sampler A (118) along the transmission direction; a solenoid valve B (215) and a second pressure gauge B (219) are provided in sequence on the fourth pipeline B (223) between the sample reactor (32) and the sampler B (218) along the transmission direction.

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