Carbon Dioxide Stripping In Bubbled Columns

Abstract

The carbonate buffer system plays a fundamental role in the biological treatments of wastewaters. In this work, the CO 2 volumetric mass transfer coefficient (k L a c ) in a bubbled column was determined using the conventional titration method for different column volumes and air flow rates. In addition, a simple method to determine k L a c based on the interpretation of the changes in the pH level due to the CO 2 stripping was developed. Results show that the apparent CO 2 volumetric mass transfer coefficient (k L a c-app ) was strongly affected by the pH level; however, the actual CO 2 volumetric mass transfer coefficient, k L a c ) k L a c-app /R 0 , was constant within the tested pH conditions. In addition, k L a c increased with higher air flow rates and lower column volumes; the obtained k L a c values ranged between 20.0 and 71.9 h -1 . For all the tested conditions, k L a c values obtained using the noncontrolled pH method were similar to the values measured using the titrimetric method. The proposed mathematical model represented adequately the changes on the pH level and total inorganic carbon species concentration as a function of time. The model was extended to take into account the effect of phosphates. Simulation results showed that, although phosphates buffered the changes of pH, the losses of total inorganic carbon were faster than in the case of a nonbuffered solution; thus, the rise in the pH level prevented the stripping of CO 2 .

Effect of CO2 stripping on pH in open‐recirculating cooling water systems

“… for CO 2 stripping from spring water in a bubbling reactor with the water pH ranging from 7.0 to 8.1. This k.a value is smaller than those reported by others for CO 2 stripping in stirred tanks and bubbled bed columns (i.e., 18–120 h −1 ) . This is mainly due to the higher mixing properties in those experiments compared to the cooling tower packing.…”

“…Contreras investigated CO 2 stripping in a bubbled column and found that, in the operating range of their column, both the gas and the liquid phase resistances were significant. However, earlier studies on the CO 2 mass transfer coefficient in packed towers have been found to be contradictory.…”

Equipment characterization to mitigate risks during transfers of cell culture manufacturing processes

“…More details to calculate the dissolved carbon dioxide concentration can be found by Minkevich and Neubert (1985), Contreras (2007), and Sieblist et al (2011a). As shown therein, the dissolved carbon dioxide content CO Ã 2 directly correlates with the pH value of the medium via H ?…”

Utilization of municipal wastewater for cooling in thermoelectric power plants

“…Although the water evaporation rate in the cooling tower can be obtained by solving Eqs. (2)- (5) to predict the water evaporation rate as well as the water flow rate through the cooling loop, these equations should be simultaneously solved with the material and energy balance equations for the entire loop using an iterative scheme. The water evaporation rate, makeup, and blowdown flow rates are related through the following mass balance equations:…”

“…Therefore, it can be concluded that at low alkalinity levels, reliable information regarding the mass transfer coefficient of ammonia is needed to predict accurately the cooling loop pH. A similar analysis was performed to determine the sensitivity of the loop pH to the CO 2 mass transfer coefficient over the wide range of values reported in the literature [5,31]. Figs.…”