Yinmin Zhang

Bio: Yinmin Zhang is an academic researcher from Inner Mongolia University of Technology. The author has contributed to research in topics: Thermogravimetry & Intercalation (chemistry). The author has an hindex of 6, co-authored 19 publications receiving 139 citations.

The thermal activation process of coal gangue selected from Zhungeer in China

Abstract: The thermal behavior of coal gangue selected from Zhungeer, Inner Mongolia Autonomous Region of China, was investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetry (TG), derivative thermogravimetry (DTG), and scanning electron microscope (SEM). The XRD data indicated that the mineral compositions of the coal gangue were kaolinite, boehmite, and quartz. The coal-gangue sample was considered as belonging to a typical mixture of kaolinite and boehmite. The XRD and FT-IR spectra clearly showed that the structural changes and dehydroxylation of coal gangue occurred with increased temperature from 100 to 900 °C. The reaction activity of coal gangue could be effectively improved by calcination. The calcined coal gangue contained considerable active amorphous Al2O3 and SiO2 and had significant loss on ignition. The optimum activation temperature range of coal gangue was from 600 to 700 °C. The dissolution contents of SiO2 and Al2O3 were 92.31 and 64.44 %, respectively, when the calcination temperature at 700 °C.

Thermal behavior analysis of halloysite selected from Inner Mongolia Autonomous Region in China

Abstract: Thermal behavior of halloysite selected from Erdos, Inner Mongolia Autonomous Region in China, was investigated by thermogravimetry and differential thermal gravity (TG–DTG), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and scanning electron microscope (SEM). The XRD results indicated that the mineralogical composition of halloysite sample was determined as 7 A halloysite with the d (001) value of 0.734 nm, a small amount of 10 A halloysite with the d (001) value of 0.998 nm, quartz, calcite, anhydrite, siderite, and analcite. The crystal chemical formula of halloysite specimen is (Ca0.007Na0.039K0.048)(Al1.935Fe 0.032 3+ Mn 0.003 2+ Ti 0.002 4+ Mg 0.015 2+ Ca 0.021 2+ )2 [(Si1.935Al 0.065 3+ )2](OH)4·2H2O according to the oxygen atom method. The TG–DTG–DSC data showed that a small amount of water molecule layer in the interlayer and the dehydroxylation was observed at 493.6 °C. The XRD, FT-IR, and SEM data clearly show that the structure changes and dehydroxylation of the halloysite with the temperature increased from 200 to 1200 °C. The dehydration of the halloysite is followed by the loss of intensity and evolution of the OH vibration bands and the change in microstructure. Dehydroxylation is followed by the decrease in the intensity of the bands at 3696 and 3620 cm−1, which is completely disappeared at 700 °C. The thermal behavior of halloysite was influenced by the mineralogy composition and impurities.

Catalytic pyrolysis of crude glycerol over shaped ZSM-5/bentonite catalysts for bio-BTX synthesis

Abstract: Ex-situ catalytic pyrolysis of crude glycerol for the synthesis of bio-based benzene, toluene and xylenes (bio-BTX) was performed in a tandem micro-reactor (TMR), a batch gram scale reactor and a continuous integrated bench scale unit using ZSM-5/bentonite extrudates. A bio-BTX yield of 8.1 wt.% (14.6% carbon yield) based on crude glycerol was obtained over the fresh catalysts (Cat-F) in the bench scale unit (crude glycerol feed rate of 200 g h−1, pyrolysis temperature of 520 °C and catalytic upgrading temperature of 536 °C). Catalyst activity was shown to be a function of the time on stream (TOS) and after 4.7 h the activity dropped with about 8%. After an oxidative regeneration step to remove coke, the activity of the regenerated catalysts (Cat-R1) was recovered to 95% of the original catalyst activity. After 11 reaction-regeneration cycles, the bio-BTX yield decreased to 5.4 wt.% (9.7% carbon yield) over Cat-R11. The fresh, deactivated and regenerated ZSM-5/bentonite catalysts were characterized in detail using nitrogen physisorption, XRD, ICP-AES, EA, TEM-EDX, TGA, NH3-TPD, pyridine-IR and solid MAS NMR. Coke (10.5 wt.% over Cat-D) was mostly deposited on ZSM-5 planes, and not only decreased the number of Lewis and Bronsted acid sites, but also blocked the pores, resulting in catalyst deactivation. Coke removal was effectively performed using an oxidative treatment. However, exchange of cations (e.g., Na) of the bentonite and possibly also from the crude glycerol feed with protons of ZSM-5 was observed, leading to irreversible deactivation. Furthermore, the layered structure of bentonite collapsed due to the removal of interlamellar water and dehydroxylation.