Upgrading Of Heavy Oil With Partial Oxidation And Process Coupling Over Iron-based Oxides

Upgrading of heavy oil is an effective way to alleviate energy shortages and improve energy efficiency.Partial oxidation over iron-based oxides can convert heavy oil into light fuels or valuable chemicals.It has important theoretical and practical significance for the development of partial oxidation technology to understand the relationship between structural characteristics of iron-based oxides and the degree of heavy oil conversion.It is also needed to develop the heavy oil upgrading coupled with other technologies.This study fouces on doping modication of iron-based oxides,the rational upgrading of heavy oil and regulation of target products,and process coupling.Metal oixdes with different valence doped with Fe2O3 and red mud(RM)were used for the partial oxidation of heavy oil to produce light fuels or chemicals.The process coupling of chemical looping partial oxidation and in-situ reduction iron-based oxides were carried out respectively.The major research contents and contributions of this dissertation are as follows:Metal oxides including Cu,Ni,Mg,Ca,Zn,Al,and Zr were doped into Fe2O3,and the partial oxidation of VR over doped Fe2O3 was evaluated.It is shown that doping metal oxide into Fe2O3 does not change hematite structure of Fe2O3.Doping Ca,Al,Zr,or Al and Zr co-doping could increase the specific surface area and pore volume of Fe2O3,and improve heavy oil conversion and diesel yield.FeAlZr-1 has the largest specific surface area and pore volume being 61.8 m2/g and 0.251 cm3/g,respectively.The diesel yield increases from 27.5 wt%(Fe2O3)to 43.8 wt%when FeAlZr-1 is used.Different amount of CeO2(Ce)doped Fe2O3 samples were prepared and used for partial oxidation of VR.The relationship between specific surface area of iron-based oxides and products distributions was discussed.The chemical looping partial oxidation(CLPOX)by using FeCe-1 as oxygen carrier was performed.It is shown that Ce doping could increase the specific surface area of Fe2O3,and the heavy oil conversion and diesel yield over FeCe-1 are 97.2 wt%and 39.8 wt%,respectively.The heavy oil conversion,yield of gas,gasoline and diesel increase and then remain stable with the increase of specific surface area.FeCe-1 shows stable performance during the CLPOX,and the the heavy oil conversion and diesel yield at 20th cycle are 87.0 wt%and 28.8 wt%,respectively.Partial oxidation of VR over RM was performed,and the process coupling of CLPOX and in-situ reduction of used RM was carried out.It is shown that RM600(RM calcined at 600℃)could decrease the cracking temperature and promote the conversion of VR.The heavy oil conversion and diesel yield over RM600 are 96.3 wt%and 8.0 wt%,respectively.The resulting liquid product is rich in linear alkanes and alkenes.The CLPOX using RM as the oxygen shows stable performance,and the heavy oil conversion,diesel yield at 20th cycle is 87.0 wt%and 29.2 wt%,respectively.Carbon deposit could partially reduce iron-based oxides in used RM to produce metallic Fe.The content of metallic iron determined by the XPS and 57Fe Mossbauer spectrum is 28.8%and 24.2%,respectively.In order to study the adaptability of partial oxidation process to different sources of heavy oil,the upgrading of coal tar by partial oxidation coupled with reduction of Fe2O3 was performed.The effect of reaction temperature on the products distribution was studied.It is shown that the increase of reaction temperature could promote the conversion of tar and increase gas yield.The C content increases,and H content and H/C ratio decrease.The content of aliphatic hydrocarbons decreases,and the content of aromatic hydrocarbons increases.When the temperature increases from 500℃ to 800℃,the content of naphthalenes increases from 8.6 wt%to 29.2 wt%,among which the naphthalene content increases significantly from 1.4 wt%to 17.2 wt%.The in-situ upgrading of PS coal pyrolysis tar coupled with reduction of Fe2O3 showed that the content of heavy components(>350℃)decreases from 52.5 wt%to 30.0 wt%.In the upgraded tar,the content of naphthalenes increases from 19.9 wt%to 30.8 wt%,among which the naphthalene content increases from 1.5 wt%to 7.8 wt%.