Microwave-assisted catalytic pyrolysis of oil-tea camellia soapstock for hydrocarbon-rich bio-oil production

Among various utilization technologies for soapstock, catalytic pyrolysis for hydrocarbon-rich bio-oil production demonstrates promising potential. However, it currently suffers from drawbacks such as low selectivity of target products, which limits its large-scale application. This study developed a microwave-assisted in-situ catalytic pyrolysis system coupled with SiC for oil-tea camellia soapstock (OTCS) upgrading and addressed the issue of slow heating rates during the microwave-assisted pyrolysis of OTCS alone, which stem from fluctuations in microwave absorption capacity. Furthermore, the system was optimized through the application of various catalysts to screen for those yielding high-yield, high-quality bio-oil. Results showed that bio-oil yield reached 64.50 wt% with a microwave power of 800 W and a HY/OTCS mass ratio of 9/10. Aromatics content increased from 26.68 % under non-catalytic to 70.69 %, while oxygen-containing compounds content decreased from 21.38 % under non-catalytic to 7.13 %. The selectivity for aromatic hydrocarbons in the bio-oil was significantly improved without a substantial decline in the overall bio-oil yield, thereby effectively enhancing its value. This study provides a theoretical basis and technical paradigm for the targeted production of high-value aromatics from soapstock, and promotes the utilization of by-products from grain and oil industry.