The co-pyrolysis characteristics of oil shale−biomass blends were investigated by open-system pyrolysis with a thermogravimetry−mass spectrometry (TG−MS) analyzer and by closed-system pyrolysis with a fixed-bed reactor. Online Fourier transform infrared (FTIR) spectrometry and gas chromatography−mass spectrometry (GC−MS) were employed to analyze the gas and liquid products that were generated from the closed-system pyrolysis. In addition, the Gaussian program was also employed for quantum chemistry calculations. According to the results, one important reaction mode of oil shale−biomass interactions can be described as the "biogas−kerogen" reaction, which means the combination of kerogen and some free radicals volatilized from the biomass in the temperature range of 180−400 °C. During the co-pyrolysis, the oil shale influences the distribution of the oxygen content in the biomass products, causing an increase of CO 2 and CO in the gaseous products and a reduction of oxygen-containing compounds such as alcohols, aldehydes, lipids, and ethers in the liquid products. The results will be useful for improving the quality of shale oil in the industrial utilization of oil shale in the future.

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A new way of utilizing oil shale is its co-retorting with wheat straw for oil. However, the process generates a great amount of combustible solid semicoke waste. To utilize this waste effectively for heating the retorting process, the current work investigated its oxidation characteristics by employing a combined thermogravimetry-mass spectrometry (TG-MS) system, and discussed the effects of three parameters, including the wheat straw mass fraction of matrix samples, as well as different ambient gases and their O 2 volume fraction, on the oxidation of the semicoke. In the presence of O 2 , the whole oxidation process of semicoke samples mainly consists of two stages: the combustion stage (300-600 °C) in which water, CO, CO 2 and pollutants are mainly released, and the decomposition stage (600-1000 °C) in which carbonates and sulphates decompose to release CO 2 and SO 2 , respectively. In the combustion stage, increasing both the wheat straw proportion of the original sample and the O 2 volume faction can improve the combustion performance of the resulting semicoke blends. In the decomposition stage, the gasification reaction also occurs to produce CO. During the entire oxidation process, semicoke in 21% O 2 /79% CO 2 would give off less NOx and SO 2 than in air. And, SO 2 formation is also influenced by the O 2 fraction, especially above 900 °C.