•It is both physically and catalytically that abundant addition of CaO influence on oil sand pyrolysis.•Addition of abundant CaO inhibited the devolatilizing during oil-producing stage.•Addition of abundant CaO do little influence on the tar yields at 480 ºC, but water and gas yields decreased obviously.•Compared with alone pyrolysis, the composition of tar had changed as the asphaltene and aromatic were reduced.•More alkanes with long carbon chain and less olefins were generated when pyrolyzed with abundant CaO additives.The influence of abundant calcium oxide (CaO) addition on oil sand pyrolysis was firstly studied by thermogravimetric analysis (TGA) and in a fixed bed reactor. CaO additives calcined from analytically pure CaCO3 (named A) and oil sand minerals (named B) were compared with the addition ratio at 1:1 (oil sand:CaO, mass ratio). Observed by TGA, abundant addition of CaO would inhibit the devolatilizing during oil-producing stage (150–600 °C). However, higher temperature appeared to weaken the inhibition effects. Comparison of pyrolysis in the fixed bed reactor was at 480 °C, 140 mL/min pure N2 carrier gas, 0.1 MPa for 40 min. When pyrolyzed with abundant CaO, the gas yields (including H2S and COS) decreased which met the result of TG/MS analysis. Tiny differences were found on tar yields which achieved around 88% of raw bitumen. But through column chromatography and gas chromatography/mass spectrometry (GC/MS) analysis, the proportion of aliphatic fraction increased, interestingly observing more alkanes with long carbon chain and less olefins. The proportion of aromatic fraction decreased by about 10 wt%, but the relative amount of polycyclic aromatic hydrocarbon (PAHs) got an obvious increase when pyrolyzed oil sand with abundant CaO. As expected, acidic compounds in resin (e.g. phenols and carboxylic acids) were significantly reduced. In general, it was both physically and catalytically that abundant addition of CaO influence on oil sand pyrolysis. But no evident differences between additive A and additive B were found on yields and product compositions.

The influence of temperature on the product distributions of oil sand fast pyrolysis was studied by a combined pyrolyzer-gas chromatography/mass spectrometry (Py-GC/MS) technique. Characteristics of the organic structure in bitumen deduced from the pyrolytic products and given by 1H/13C nuclear magnetic resonance (NMR) spectrometry were compared as well. The oil sand sample was pyrolyzed at temperatures from 300 to 650 °C in intervals of 50 °C in an inert atmosphere (helium gas), and more than 200 types of compounds were detected, including carbon dioxide, aliphatics (alkanes, cycloalkanes, olefins, dialkenes, cycloolefins), aromatics (alkyl benzenes, alkyl naphthalenes, alkyl indenes), oxygen-containing compounds, and sulfur-containing compounds. From the evolution of the product yields, it was clearly observed that temperature affected both the primary and secondary reactions during fast pyrolysis. Major thermal cracking took place until about 400 °C, as evidenced by a dramatic increase in product species and yields. However, temperatures higher than 600 °C were beneficial for generating smaller molecules as products. Among the pyrolytic products, alkanes and olefins were predominant and were mainly derived from the thermal cracking of abundant polymethylene substituents linking to the aromatic cores. It was found that the yields of alkanes and olefins decreased with increasing carbon number, and more olefins were generated at higher temperatures. Monoaromatics with more alkyl or alkenyl multisubstituent groups appeared above 400 °C, but the substituent groups were no longer than isopropyl. In the range of 300–650 °C, few polycyclic aromatic hydrocarbons were observed. Higher temperatures also obviously enriched the species of naphthalene, indene, and compounds with heteroatoms. In addition, the raw aliphatic sulfur in the sample tended to be converted into sulfur-containing heterocycles during fast pyrolysis in an inert atmosphere. The results of this study show that both the NMR and Py-GC/MS methods can provide information on the organic structures in oil sand. However, NMR spectrometry is able to present an overview of the structure of hydrocarbons, whereas Py-GC/MS can help to deduce some characteristics of the macromolecules in oil sand organics.

Ni2P/CNTs was synthesized using an impregnation method. XPS revealed that CNTs could affect the electronic properties of bulk Ni2P. The catalyst shows superior activity for HYD of naphthalene with a conversion of 99%, and demonstrates superior tolerance towards potential catalyst poisons, which is higher than Ni/CNTs with a conversion of 89%.