چكيده به لاتين
Bubble column reactors are intensively used as a multiphase contactors and reactors in many industries. They have many advantages compared to other reactors, such as simple geometry, high mass and heat transfer coefficients, low operating and maintenance costs. In present study, the bubble column has been applied in order to reactive absorption of the carbon dioxide (CO2) by aqueous piperazine (PZ) solutions. Due to the very highly reactivity with CO2 and low regeneration energy, PZ is commonly used as promoter in CO2 absorption processes. In a gas-liquid system with the chemical reaction, the interactions between the prevailing processes are very complex. Therefore, the mathematical model that used to express reactive absorption process in bubble columns should be include the hydrodynamics, mass transfer, heat transfer and kinetics of chemical reactions. In this work a two-dimensional computational fluid dynamics (CFD) model in Eulerian framework has been used to description of the transport phenomena in the bubble column. For the numerical solution of governing equations, the space-time conservation element and solution element (CESE) method has been applied. The CESE is a high-resolution CFD method for solving conservation laws. Basically, the methodology and concept of CESE is different from the other traditional methods. This method has been designed to overcome the disadvantages of other conventional methods. The MATLAB software has been used to solving the governing equations. The piperazine concentration, CO2 partial pressure, stirrer speed and liquid flow rate were in the range of 0.1–0.5 M, 20–36 kpa, 0–300 rpm and 0-2 lit.h-1, respectively. Also, operation condition for temperature and pressure were constant values of 295 K and 1 atm, respectively. The experimental results show that CO2 removal efficiency and gas holdup were varied in range of 65.5–82.1% and 0.06–0.076, respectively. The simulation results illustrate the 3% error in in gas holdup prediction and 5–12% for CO2 removal efficiency.
