ABSTRACT
The key point of study on CO2 removal by microalgae cultured in a photobioreactor is to improve CO2 removal capability. In this paper, a model of air-lift photobioreactor was developed by combination of conditions including the velocity of flow, the degree of mixing, the gas-liquid mass transfer and the rate of photosynthesis, and two corresponding simplified methods, such as time discretization and lumped parameters were put forward. Using a method of lumped parameters, the model for simulation of time course of DO, pH in the column air-lift photobioreactor and prediction of CO2, O2 concentrations in the outlet gas under different CO2 concentration in the aeration gas was thoroughly discussed. Experimental data were also used to verify the model which could potentially be applied to rational design of the photobioreactor, high-density culture of microalgae and efficient removal of CO2.