Ağır ve konvansiyonel olmayan yağların yüksek yoğunluklu/süperkritik su ile dönüşümünün incelenmesi

Upgrading of different types of bitumen, refinery side streams, heavy oils extracted from tar sand samples, and bitumen blended with microalgae Chlorella vulgaris was investigated in supercritical water (SCW) at 440 °C and 30 MPa in a home-made batch type bomb reactor. The effects of microalgae fraction in the feeds ranging from 0 (pure bitumen) to 100 wt. % (pure microalgae) and the effects of the water/feed ratio ranging from 2 to 10 were investigated. The effects of catalytic additives, reaction time and feed chemistry were studied. Five lumps kinetic model was derived. As a reference analysis, pyrolysis experiments in the absence of water were performed under the same reaction conditions. As for the results of microalgae upgrading, SCW was found to suppress the coke formation. 25 wt. % microalgae addition to bitumen increased VR conversion 20% with a considerable increase in gas content and diesel yield. Increasing microalgae fraction in the feed to 50 wt. % resulted in increased light liquid yields due to increasing conversion of VR and also led to undesired increases in coke and gas formation. Water/feed ratio of 10 led to increased gas yields with a lower VR conversion. As for the results of upgrading of varying heavy oil feeds, the tendency of coke suppression by SCW was found to be higher for tar sand feeds compared to bitumen samples. Low vacuum residue (VR) together with high amounts of lighter ends in the feed were shown to decrease the coke yields even if there are high amount of asphaltenes. Long reaction times resulted in similar yields and selectivities for different feeds. Use of iron containing red mud samples as an entrainer left hexagonal shaped column like deposits over the surface of the coke samples. The effect of sulfided forms of iron additives was shown to largely depend on reaction time. Tar sands were shown to be the optimum heavy oil resource for the upgrading studies performed in the presence of SCW for 40 minutes under the reaction conditions of this study.