Experiments on ion exchange membrane
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To achieve the goal of increasing the amount of biofuels, esters with theiracid and alcohol components made from lignocellulose can be a sustainabletechnology. The maximal achievable concentration of carboxylic acids from afermentation process is low and without an effective means of separation thisis not a viable economic option compared to production from petrochemicals.To date the most promising technique for separation is membrane electrodialysis.This technique allows the removal of the acids without harming thefermentation stock. In this master project experiments on an electrodialysis membrane hasbeen designed and the setup and design have been adjusted to each other inorder to run the experiment. The design was made to explore a large part ofthe possible operational area to recommend areas to be further researched. Afactorial design was chosen due to the large amount of information given bythe few number of experiments. The goal was to see the effects of electricalcurrent and the concentration of acetic acid on different performance indicators.This included the temperature, pH, coulombic efficiency, yield, acetateremoval rate and removal time. To analyse the performance different onlinemeasurements techniques were applied these included pH, temperature andelectrical potential and current logging. Samples from the experiment wereanalysed by HPLC and analysis of variance was performed on these resultsto check for any correlations and discover how the system might evolve. The analysis of variance showed that the experimental variables had asignificant effect on the Coulombic efficiency and rate of transfer. For bothof them, the interaction had a significant effect. The results from the analysisof variance indicated that the best operating conditions were at a highconcentration and a strong electrical current. This operational mode had alower electrical resistance during four hour runs indicating that the optimaleconomical performance is situated in the same area. The yield showed nosignificance. The catholyte pH increased in all experiments and reached asteady state around pH 12.5 while the anode pH remained constant. Thetemperature for both compartments increased because of the electrical resistance.