Study the effect of different types impellers on the transfer coefficient in photobioreactor.

Abstract

Abstract In this research, study the effect of different types of impellers on the overall volumetric mass transfer coefficient, (determination of KLaO2 is very important for photobioreactor design and process analysis, Where through measuring KLaO2, the volumetric mass transfer coefficient of carbon dioxide is calculated based on the following relationship klaCO2 = 0.9 klaO2 Which is one of the most key factors that depend on it in the design of the photobioreactor )then make comparison between them, the impellers type which used in this research is 4-blade propeller, mixed flow impeller, 2-blade propeller(plastic), a hybrid photobioreactor type has been used in this research, which is a mixture of a bubble column and the stirred tank photobioreactor, The variables that studied in this research are the impeller speed (100-500) rpm, the rate of airflow into the reactor (1-4) L/min, and the type of impeller used. KLaO2 can be measured by static gassing out method. Through practical experiments, it was found that the highest value of KLaO2 in the 4 blade propeller was at a flow rate of 2 liters per minute and impeller speed 500 rpm, which equals 0.0091 (1 / s). As for the impeller (mixed flow impeller), the highest value of KLaO2 was at a speed of 500 rpm and a flow rate of 4 L / min which equals 0.0118 (1 / s). The highest value of KLaO2 in the impeller 2 blade propeller (plastic)) was at a flow rate of 4 liters per minute and impeller speed 500 rpm which was equal to 0.0101 (1 / s).A comparison is made between the three impellers on the basis of their efficiency in giving high values of KLaO2, where it was found that the mean value of the KLaO2 for the impeller (mixed flow impeller) is higher than the other impellers, where the average value of the KLaO2 at a speed of (100-500) rpm and the flow rate(1-4)L/min is 0.00806 (1 / s). This means that the type of impeller (mixed flow impeller) has a high efficiency of mixing and mass transfer between gas and liquid. In this study, correlation equations were developed for each impeller to see the correctness of the results according to specific exponents and constants within the range of previous studies and research, and it was found that theoretical volumetric mass transfer coefficient values are close to practical volumetric mass transfer coefficient values.