Numerical Simulation Of Sodium Hydroxide Absorbing Carbon Dioxide Gas In Bubble Column

Climate warming is the most serious among the world’s ten biggest environmental problems. Foreign scholars reach an agreement on the reason why climate is becoming warm."The climate change assessment report for the fourth time" of PICC indicates that human activities cause the climate warming most probably. With the fast development of industry, a large number of carbon dioxide increase caused by the burning of fossil fuels. The greenhouse effect intensifying is a major topic of discussion which many countries in the word talk about. Therefore, to curb emissions of carbon dioxide is significant. Among of power plant flue gas removal technologies, the chemical absorption method remains in a larger proportion. As industrial reaction container, bubble column is widely used in the removal of carbon dioxide from flue gas.This paper describes simulations that were performed with an Euler-Lagrange method in the Fluent software platform. The model is used to simulate the process of carbon dioxide in an aqueous NaOH solution in bubble column.Firstly, it investigates flow characteristic in bubble column coupling with chemical reactions and mass transfer. The research finds that gases bubbled into the bubble column will cause disturbance to the liquid phase. With the development of flow, the ascensional motion of bubble flow becomes distorted and incurs opposite eddy currents arranging the up and down. Then, the eddy currents extend to the axial and radial direction.Secondly, it investigates that the mass fraction of carbon dioxide decreases with increasing height of the reactor. It is lower in the center of the reactor and higher in the near wall region. In addition it investigates the distribution of chemical composition. The research finds that the process of sodium hydroxide absorbing carbon dioxide is divided into two sections. The first section is a process that hydroxyl is coming to reduce and the concentration of carbonate ions is gradually increasing until the peak. Carbon dioxide is absorbed in a faster reaction rate. The second section is a process that carbonate turns to bicarbonate root. Carbon dioxide is absorbed in a slower reaction rate than the first section.Finally, it investigates the influence on removal efficiency, absorption rate and mass transfer coefficient in different operating parameters. The removal efficiency decreases with increasing concentration of carbon dioxide in flue gas and the gas flow. The absorption rate increases with increasing concentration of carbon dbxide in flue gas and the gas flow. The mass transfer coefficient increases with increasing concentration of carbon dioxide in flue gas and the gas flow. The absorption effect of10%sodium hydroxide solution is the best.