Hydrodeoxygenation Research Of Catalytic Pyrolysis Oil From Algea On Ni-Cu Supported Catalyst

Bio-oil energy has gradually became a hot research field with shortage of fossilfuels and the increasing energy demand. Algae biomass has a great amount ofproduction and a short growth cycle, and it does not take up cultivated land comparedwith wood and oil crops biomasses, thus it gradually becomes the focus of bio-oilenergy in recent years. However, high oxygen content leads to high viscosity, highacid value, and less stability of bio-oil generated from catalytic pyrolysis ofalgaebiomass.The aim of this thesis is to develop a low-cost, high-activity and stablehydrodeoxygenation catalyst apllying to the hydrodeoxygenation process of pyrolysisoil from algae. It obtained a upgraded bio-oil with high calorific value, low kineticviscosity and low water content by means of hydrodeoxygenation.Hydrodeoxygenation activity of Ni-Cu/ZrO2catalyst and its active stability wereexamined in in a lab-scale flow fixed bed reactor, using fast pyrolysis of Clorella asraw oil. The surface properties of Ni-Cu/ZrO2catalyst were characterized by XRD,TPR, TG and NH3-TPD techniques. In the process of catalytic hydrodeoxygenation,the improvement of bio-oil performances was studied. It showed that the addition ofCu promoted the dispersion of active species on Ni-Cu/ZrO2catalyst. With theaddition of Cu, catalytic hydrodeoxygenation activity of Ni-Cu/ZrO2catalyst increasedin the catalytic hydrodeoxygenation process. Nevertheless, catalytic activity of thecatalyst was reduced when the loading of Cu was too high. At2MPa and350C, theoxygen content of the bio-oil decreased sharply on Ni-Cu/ZrO2catalyst with stablecatalytic performance. In this case, the removal efficiency of oxygen content inupgraded bio-oil collected after3h continous running decreased by82%whenNi-Cu/ZrO2(Cu/Ni=0.40, mass ratio) was used as catalyst, and the removal efficiency was still excess77%in upgraded bio-oil collected after24h continous running.Hydrodeoxygenation activity and stability of Ni-Cu/ZrO2was high than those ofNi-Mo-S/Al2O3, which was used mostly in the hydrodeoxygention process of bio-oil.ZrO2-Al2O3composite supporters with different ZrO2content were prepared bythe impregnation-precipitation method, and then they were used as supporters of Ni-Cubimetal catalyst to reduce cost and increase activity of the catalyst.Hydrodeoxygenation activities of the above-mentioned catalysts for catalytic pyrolisisoils from chlorella and nannochloropsis oculata were investigated in a lab-scale fixedbed reactor. It showed that specific surface area of Ni-Cu/ZrO2-Al2O3was significantlyhigher than that of Ni-Cu/ZrO2, and dispersion of active phase on the catalyst was alsouniformly obviously. A small amount of ZrO2in ZrO2-Al2O3could increase thenumber of acid sites of Ni-Cu/ZrO2-Al2O3, and improved activity of thecatalyst.However, too much ZrO2in ZrO2-Al2O3could decrease the amount of acidsites and specific surface area of Ni-Cu/ZrO2-Al2O3, thus, activity of the catalystreduced. Ni-Cu/ZrO2-Al2O3has the highest hydrodeoxygeantion activity when thecontent of ZrO2in ZrO2-Al2O3composite supporter was20%(this compositesupporter was signed as ZA20) in the hydrodeoxygenation process.Hydrodeoxygenation activity of Ni-Cu/ZA20to catalytic pyrolisis oils fromchlorella and nannochloropsis oculata were both very high, whose removal rates ofoxygenic components in the bio-oil were all very high. Deoxygenation efficiencies ofupgraded bio-oil collected after3h continous running were90%and86%,respectively. Therefore, most of acids, alcohols, aldehyde, ketone and amides inupgraded bio-oil were removed. As a result, the catalyst is suitable for thehydrodeoxygenation process of catalytic pyrolysis oil from common algae.Heat value and cetane number of upgraded bio-oil from the hydrodeoxygentioncatalytic pyrolisis oil from nannochloropsis oculata were increased to40MJ/Kg and50, respectively. Meanwhile, kinetic viscosity at40.0℃of the bio-oil fell to5.6mm2·s-1, all three indexes had reached the standards of commercial diesel. In addition,water in upgraded bio-oil could be removed easily, and stability of the bio-oilenchanced significantly.