In situ catalytic upgrading of heavy crude oil through low-temperature oxidation

The low-temperature catalytic oxidation of heavy crude oil（Xinjiang Oilfield,China） was studied using three types of catalysts including oil-soluble,watersoluble,and dispersed catalysts.According to primary screening,oil-soluble catalysts,copper naphthenate and manganese naphthenate,are more attractive,and were selected to further investigate their catalytic performance in in situ upgrading of heavy oil.The heavy oil compositions and molecular structures were characterized by column chromatography,elemental analysis,and Fourier transform infrared spectrometry before and after reaction.An Arrhenius kinetics model was introduced to calculate the rheological activation energy of heavy oil from the viscosity-temperature characteristics.Results show that the two oil-soluble catalysts can crack part of heavy components into light components,decrease the heteroatom content,and achieve the transition of reaction mode from oxygen addition to bond scission.The calculated rheological activation energy of heavy oil from the fitted Arrhenius model is consistent with physical properties of heavy oil（oil viscosity and contents of heavy fractions）.It is found that the temperature,oil composition,and internal molecular structures are the main factors affecting its flow ability.Oil-soluble catalyst-assisted air injection or air huff-n-puff injection is a promising in situ catalytic upgrading method for improving heavy oil recovery.

Degradative solvent extraction of low-rank coal:Role of water on pyrolysis mechanism of low-rank coal in a highly-dispersed medium

A degradative solvent extraction(DSE)method was proposed to upgrade low-rank coals(LRC)for their cascaded utilizations in a highly-dispersed medium.The derived products exhibited well improved properties in comparison to the raw LRCs.Previously,the LRCs were pre-dried to eliminate the potential impact of the varied water content of raw LRCs,but in light of the abundant water in fresh coals,the hydrolyzing effect of water on coals under heating,and the energy cost to pre-dry the LRCs,it is consequently essential to clarify the effect of water so as to verify the necessity of pre-drying process.In this study,the roles of inherent water and extra-added water were respectively investigated,using dried,raw and wet coals from two typical LRCs.The results show that increasing the moisture content of raw LRCs contributed to the extraction ability of DSE method without noticeably changing the elemental composition,chemical structure and thermal decomposition behavior of extractable products,thus pre-drying of LRCs before DSE treatment was proven unnecessary.Additionally,the roles of the inherent water were concluded as:1)leading to the formation of stable covalent bond during drying process;and 2)acting as H donor to promote extraction ability,while the added water can only function as H donor.Since excessive water will increase the pressure during DSE treatment and lead to the waste water treatment,the LRCs with a water content between 10%and 30%were consequently recommended for the practical application of DSE treatment.