SEPARATION OF OIL FROM EMULSION AFTER CENTRIFUGATION

Cilj diplomske naloge je ločiti olja iz emulzij s centrifugiranjem in z laboratorijsko simulacijo hidrociklona. S fizikalno-kemijskimi analizami smo ugotavljali učinkovitost centrifugiranja in turbulentnega mešanja, pri tem pa preučevali, kako na ločevanje emulzij vplivajo čas obdelovanja, temperatura, število obratov in dodatki sredstev NaCl, CaCl2 in polialuminijev klorid (PaCl). Rezultati kažejo, da se s povečevanjem števila obratov centrifugiranja, poveča tudi učinkovitost ločevanja emulzij (najboljše rezultate smo dobili pri najvišjih obratih – 7000 obr./min). Pri poskusih, kjer smo spreminjali čas centrifugiranja, smo največ olja iz emulzij odstranili po dveh urah centrifugiranja, ob tem pa ugotovili, da se največ olj odstrani prvo uro, z nadaljnjim centrifugiranjem pa se ta delež bistveno zmanjšuje. Na ločevanje emulzij pozitivno vplivajo tudi dodana sredstva, pri katerih so se vrednosti najbolj znižale ob najnižjih koncentracijah (0.15 g/L (NaCl), 0.15 g/L (CaCl2) in 1.2 g/L (PaCl)) ter povišana temperatura emulzij, kar prikazujejo rezultati centrifugiranja pri 55 °C, ki so veliko boljši kot tisti pri 22 °C. Motnost, kemijska potreba po kisiku (KPK) in vsebnost olj se bistveno znižajo, kljub temu pa metoda za popolno in samostojno ločevanje emulzij ni dovolj učinkovita. Na podlagi rezultatov fizikalno-kemijskih analiz po poskusih v hidrociklonu ugotovimo, da hidrocikloniranje pri 1000 obr./min ni primerno za ločevanje oljno vodnih emulzij, saj se vrednosti motnosti in barve niso bistveno znižale.The aim of this undergraduate thesis is to separate oil from emulsions with centrifugation and with a laboratory simulation of hydrocyclone. We have researched the effectiveness of centrifugation and turbulent mixing with physical and chemical analyses and studied how the separation of emulsions is influenced by time of processing, temperature, the number of rotations and admixture of compounds such as NaCl, CaCl2 and polyaluminium chloride (PaCl). The results show that by increasing the number of revolutions of centrifugation, the effectiveness of emulsion separation (we have obtained the best results at the highest rotational speed of 7000 r.p.m.) also increases. When we have changed centrifugation time, we removed the most of oil from the emulsions after two hours of centrifugation and found that the most oil has been removed in the first hour and that the share droped significantly in the remaining period of centrifugation. The addition of salts positively affects the separation of emulsions, the values of which have dropped the most at the lowest of concentrations (0.15 g/L (NaCl), 0.15 g/L (CaCl2), and 1.2 g/L (PaCl)) as well as the higher temperature of emulsions which are shown by the centrifugation results at 55 °C. The latter are much better compared to the results at 22 °C. Turbidity, chemical oxigen demand (COD) and oil presence are significantly lower nevertheless the method is not effective enough for total and individual separation of emulsions. Based on the results that we have gained with physical and chemical analyses in hydrocyclone, we have found that fast mixing at 1000 r.p.m. is not appropriate for separation of oil-in-water emulsions since the value of turbidity and colour have not significantly dropped