Catalytic pyrolysis of spent bleaching clay for its regeneration and simultaneously producing aromatic hydrocarbons

This study was focused on the value-increment of spent bleaching clay (SBC) to produce aromatic hydrocarbons and regenerated bleaching clay (RBC) via ex-situ catalytic pyrolysis with HZSM-5. The catalytic pyrolysis experiments were conducted to clarify the regulatory functions of pyrolytic temperature and SBC-to-HZSM-5 ratio (S/H) on the product distribution and aromatics generation. The adsorbed oil in SBC could be decomposed almost completely at 450 degrees C. The optimum aromatics yield of 3.49 wt% was achieved at catalytic temperature of 600 degrees C and S/H of 15. The solid product obtained under this condition underwent calcination at 500 degrees C and acid treatment successively to prepare RBC. The treatment did not affect the montmorillonite structure of clay. The RBC possessed good porous structures with newly generated micropores. The specific surface area and pore volume of RBC reached 163.32 m2/g and 0.29 cm3/g, higher than those of 146.17 m2/g and 0.25 cm3/g of fresh activated bleaching clay (ABC), indicating the better adsorption performance of RBC.

Automated summary

This study focused on the value-increment of spent bleaching clay (SBC) to produce aromatic hydrocarbons and regenerated bleaching clay (RBC) via ex-situ catalytic pyrolysis with HZSM-5. The results showed that the adsorbed oil in SBC could be decomposed almost completely at 450 degrees C. The optimum aromatics yield of 3.49 wt% was achieved at catalytic temperature of 600 degrees C and S/H of 15. The RBC obtained after calcination and acid treatment possessed good porous structures with improved adsorption performance compared to fresh activated bleaching clay (ABC).