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.

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

Preparation, morphology, and structure of kaolinites with various aspect ratios

Using low-rank coal slime as an eco-friendly replacement for carbon black filler in styrene butadiene rubber

Emerging paraffin/carbon-coated nanoscroll composite phase change material for thermal energy storage

An application‐oriented roadmap to select polymeric nanocomposites for advanced applications: A review

Characterization of kaolinite/styrene butadiene rubber composite: Mechanical properties and thermal stability

The differences in structure and thermal behavior of two Chinese bentonites (X-1 and J-1) are analyzed by thermogravimetry (TG), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy. The TG–DTG–DSC data indicated that two water molecular layers were present in the interlayer of the X-1 bentonite, but one water molecule layer in the interlayer of the J-1 bentonite. The mineralogy of the X-1 bentonite sample was determined as calcium montmorillonite, opal-CT (OCT), and quartz (Q), but that of the J-1 sample was determined as sodium montmorillonite, OCT, and Q. These results correspond to the TG–DTG–DSC data. The XRD and FT-IR spectra clearly show that the structural changes and dehydroxylation of these two bentonites occur when temperature is raised from 25 to 900 °C. The bentonite samples lose adsorbed and hydration water up to 300 °C, between 300 and 750 °C, and then the 2:1 layer structure completely collapses by rising the heating temperature from 25 to 900 °C. The dehydration is followed by the loss of intensity and evolution of the OH vibration bands and the change of interlayer spacing. The typical bands identified in the FT-IR spectra are similar for these two bentonites, but there are some differences in their positions and intensities. Dehydroxylation is followed by the decrease in intensity and position in the bands at 3620 and 910 cm−1, which is completed by 600 °C. The thermal behavior of these two bentonites was influenced by the impurities, ion substation, and the types of interlayer cations.

Yongfeng Zhang

Papers

Characterization of kaolinite/styrene butadiene rubber composite: Mechanical properties and thermal stability

Thermal behavior analysis of two bentonite samples selected from China