Gas phase chemical reaction heat measurement system and method based on heat flow method calorimeter

Abstract

The invention relates to a gas phase chemical reaction heat measurement system and method based on a heat flow method calorimeter (RC1e type). An inert medium and a small gas phase reactor are additionally arranged in a reaction kettle of an original heat flow method calorimeter, a gas raw material is introduced into the gas phase reactor for reaction, and heat released by the reaction is transferred to a calorimetric system through the inert medium for real-time monitoring. The method solves the problem that a traditional heat flow method calorimeter cannot directly measure gas-gas reaction heat, the application range of the calorimeter is expanded, and the method is suitable for gas-phase reaction thermodynamic research and process safety evaluation under high-temperature and high-pressure conditions.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of chemical reaction calorimetry, and specifically relates to a method and system for measuring gas-gas reaction heat using a heat flow calorimeter (RC1e, etc.), which is suitable for thermodynamic research and process safety assessment of high-temperature catalytic reactions, gas-phase synthesis and combustion reactions. BACKGROUND

[0002] Traditional heat flow calorimeters (such as Mettler Toledo RC1e) calculate heat flow by monitoring the temperature difference between the reactor jacket and the reaction system, and are widely used in the measurement of heat of liquid-liquid, liquid-solid and gas-liquid reactions. However, gas-gas reactions cannot be directly measured by conventional calorimeters due to the lack of liquid medium as a heat transfer carrier. In the prior art, gas-phase reaction heat is often obtained by theoretical calculation or indirect experiment (such as bomb calorimetry), which has the defects of low precision, complex operation and difficulty in real-time monitoring. CN117314167A; CN117314167B disclose a method for evaluating the safety risk of continuous flow gas-phase reactions in a tubular reactor, which describes a method for evaluating the safety risk of continuous flow gas-phase reactions. In the above documents, only the method for evaluating the safety risk of continuous flow gas-phase reactions is described, and no specific and perfect calorimetry method is proposed for the common gas-gas reactions in the chemical industry.

[0003] Gas-gas reaction refers to a chemical reaction between two or more gases under certain conditions. This reaction usually occurs in the gas phase, and both the reactants and the products are gaseous. SUMMARY

[0004] The present application aims to provide a gas-phase reaction heat measurement system and method based on a heat flow calorimeter, which breaks through the limitations of traditional equipment and realizes direct and accurate measurement of gas-gas reaction heat.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: first, inert medium (such as silicone oil) is filled in the RC1e reactor as a heat transfer medium; second, a small gas-phase reactor is built-in, its cavity is in full contact with the inert medium, and the gas is input and output through independent pipelines; third, the gas delivery unit integrates mass flow controllers and preheating modules to ensure controllable gas conditions.

[0006] The method flow is as follows: first, after the inert medium is temperature-controlled and stabilized, the reaction gas is introduced to trigger the reaction; second, the reaction heat is transferred to the inert medium through the gas-phase reactor wall, and the temperature difference is monitored in real time by the jacket sensor; third, the heat flow balance equation Q reaction =Q flow +Q accumulation +Q feed =UA×ΔT+(M r ×C pr +M gas-phase reactor ×Cp gas-phase reactor +M catalyst ×C p catalyst )×(dT r / dt+dM r / dt×C p feed ×(T r -T feed )) Calculate the reaction heat and dynamically analyze the exothermic curve using data processing software such as iControl.

[0007] Advantages of this invention: It proposes a targeted, comprehensive reaction calorimetry method for gas-gas reactions. It is compatible with existing RC1e hardware and can be expanded to gas-phase reactions with only structural modifications. An inert medium acts as a "thermal bridge," ensuring efficient heat transfer and measurement of gas-gas reactions. It supports high-temperature and high-pressure conditions, making it suitable for industrial-scale catalytic reactions and safety assessments. Data obtained using this method can provide the underlying foundation for chemical reaction risk assessments, subsequent process design, and scale-up, laying the foundation for achieving process safety and improving quality and efficiency. DETAILED DESCRIPTION

[0008] The specific embodiments of the present invention are further described below with reference to examples. It should be noted that the specific embodiments described here are only for illustrating and explaining the present invention, and are not intended to limit the present invention.

[0009] Measurement of the heat of reaction of methane catalytic combustion 1. System configuration: 1.1 Use RC1e High Temp model, reactor volume 2L, filled with high temperature silicone oil (-50~300℃); 1.2 The gas phase reactor is made of Hastelloy C22, with a volume of 200 mL and a built-in Pt / Al2O3 honeycomb catalyst; 1.3 The gas delivery unit contains a mass flow controller (CH4 to O2 ratio 4:1), preheated to 150℃, and the introduction rate is controlled to ensure that the outlet temperature of the small gas phase reactor is the same as the reaction temperature, and the tail gas is collected for necessary testing.

[0010] 2. Experimental steps: 2.1 Start RC1e, heat the silicone oil to 200℃ and stabilize it; 2.2 N2 was introduced into the gas phase reactor for 10 minutes; 2.3 A mixture of CH4 and O2 was introduced at 50 mL / min to trigger the combustion reaction; 2.4 The jacket temperature (Tj), medium temperature (Tr), and heat flow (Q) were recorded using the iControl software, and ΔH = -802 kJ / mol was calculated (deviation from the theoretical value <3%).

[0011] Industrial applications The present application can be widely applied to the research of gas phase reaction thermodynamics, catalyst screening and process safety evaluation in petrochemical, pharmaceutical and new energy fields, and provides key data support for reactor design and risk control.

Claims

1. A gas phase chemical reaction heat measurement system based on heat flow calorimeter, characterized in that include: The main body of the heat flow calorimeter includes a reactor, a jacket temperature control system, a sensor, and a data acquisition module; Inert medium, filled in the reactor, used to absorb and transfer heat; Small gas phase reactor, immersed in an inert medium, with a gas-gas reaction chamber inside, equipped with a gas inlet, outlet and catalyst carrier, with high heat exchange efficiency, which can transfer the heat released by the reaction to the inert medium in a timely manner; The gas delivery unit is used to introduce reaction gas into the gas phase reactor and control the flow rate and pressure.

2. The system according to claim 1, characterized in that The inert medium is silicone oil, mineral oil or high-temperature stable liquid, with a thermal conductivity of ≥0.1 W / (m·K) and a boiling point 50° C. higher than the reaction temperature.

3. The system according to claim 1, characterized in that The gas phase reactor is made of high temperature and corrosion resistant metal (such as Hastelloy C22) or quartz glass, and its volume is 1% to 10% of the total volume of the reactor. A honeycomb or porous catalyst carrier is provided inside.

4. The system according to claim 1, characterized in that The gas delivery unit includes a mass flow controller, a pressure sensor and a preheating module to ensure that the gas reaches the set temperature and pressure before entering the reactor.

5. A method for measuring the heat of a gas-phase chemical reaction based on the system of claims 1 to 4, characterized in that The following steps are involved: Fill the reactor with inert medium and start the jacket temperature control system to stabilize the medium temperature; Immerse the gas phase reactor in an inert medium and introduce an inert gas purge system; Introduce the reaction gas into the gas phase reactor, control the flow rate and pressure, and trigger the gas-gas reaction; The temperature change of the inert medium is monitored in real time by sensors, and the reaction heat (ΔH) and heat release rate are calculated using the heat flow method.

6. The method according to claim 5, characterized in that The heat transfer coefficient (UA) and effective heat exchange area of ​​the gas phase reaction were calculated using the modified jacket temperature (Ta) and virtual volume (Vv) model.

7. The method according to claim 5, characterized in that Through the heat flow data acquisition software of heat flow calorimeters such as RC1e, reaction thermodynamic curves are generated in real time, gas phase reaction heat data are obtained, and a safety risk assessment report is issued.