Assignment: Dialysis

Abstract

The main purpose of this experiment is to measure the overall mass transfer coefficient of a Fresenius F80A hemodialyzer and to determine the resistances of the lumen, membrane, and shell mass transfer at different shell and lumen flow rates. Because of cost and safety concerns, sodium chloride is used as a feed in the lumen and tap water as a dialysate in the shell in order to evaluate the performance of the hemodialyzer. It is observed that as flow rates increase, the overall mass transfer coefficient increases as well, as a conductivity value (electrolytic) of exiting fluid increases. This was done by measuring the flow rate and conductance of the liquids entering and exiting the F80A hemodialyzer.

Conclusion

The overall mass transfer coefficient in the hemodialyzer can be increased by increasing the flow rate of the lumen and shell, until a limit established by the membrane is reached. The results can be attributed to any number of sources of error. Some including manual reading errors during calibration of the flow meters and the values for calibrating the conductance meters have likely changed since their last calibration. The largest source of error is most likely from having too few data points. It is hard to determine the relationship between certain aspects with just two or three data points.