Measurement of gas-liquid reaction heat based on synchronous thermal tracking

Abstract

In the process of CO2 capture by chemical absorption, regeneration energy consumption accounts for 70%-80% of the total energy consumption. Currently, the most critical issue is how to reduce the energy consumption of regeneration. Equipment such as micro-reaction calorimeter (Thermal Hazard Technology provides), differential reaction calorimeter and Setaram C80 thermal differential calorimeter is used to compare the reference and sample solutions, which are simultaneously heated to compensate for heat loss of the sample solution during the measurement, but the heat of reaction cannot be directly measured. In this study, the reaction heats of MEA (ethanolamine) and MDEA (N-methyldiethanolamine) with CO2 at 10%, 20%, 30%, 40%, and 50% mass fraction were measured by synchronous thermal tracing technique. By synchronously controlling the temperature of the shell of the container and the internal solution, the temperature gradient was reduced to form a "thermal barrier"to prevent the solution from exchanging heat with the external environment in the form of conduction, convection, or radiation. A dynamic adiabatic environment was obtained without thermal compensation. The accuracy of direct measurement of the trace gas-liquid reaction heat was improved to save the sample amount. The experimental results show that the simultaneous thermal tracking method is more accurate. With the increase of solution concentration, the reaction heat of MEA first decreases and then increases, and the reaction heat of MDEA decreases gradually. When the mass concentration of MEA and MDEA is between 20% and 40%, the mass concentration has no significant effect on the reaction heat. The curve of temperature rise formed by exothermic reaction appears to be concave.

Keywords

• synchronous thermal tracking
• trace reaction heat
• absorption
• chemical reactor