Absorption of Carbon Dioxide Characterized by Using the Absorbent Composed of Piperazine and Triethanolamine

ABSTRACT

This work studies the CO₂ absorption of alkanolamine, piperazine, and TEA (triethanolamine), and the chemical reaction kinetics of CO₂ by using the mixed solution of piperazine and TEA in polyvinylidinefluoride hollow fiber membrane contactor-stripper hybrid process. Absorption was studied from 303K to 382K in the mixed solution of piperazine 0.26 M, 0.64 M, and TEA 0.38 M, 1.13 M, 2.26 M. Also, absorption rates were measured as a function of CO₂ partial pressure in the mixed solutions. The increase of the initial absorbent concentration and CO₂ partial pressure showed a high absorption rate of CO₂. Our experiment revealed that the absorption capacity of the mixed absorbent of TEA and piperazine with CO₂ was mostly governed by the piperazine concentration. The TEA is a tertiary amine with low CO₂ absorption capacity, but it helps the hollow fiber membrane keep the non-wetting condition in the fiber’s pores because of the high viscosity of TEA. Therefore, the addition of piperazine to TEA, which has too low absorption capacity with CO₂, makes it possible to obtain a high CO₂ removal efficiency. Finally, the kinetic data on the reaction of piperazine and CO₂ were investigated, and the activation energy was calculated through the Arrhenius expression.

Key Words::

• Carbon dioxide absorption
• Piperazine
• Triethanolamine
• PVDF hollow fiber
• Membrane contactor