High‐Intensity Microwave‐Assisted Pyrolysis Liquid Subjected to Supercritical Fluid Extraction with Carbon Dioxide (Case Study: Bio‐phenol)

Abstract A crude bio‐oil from high‐intensity microwave‐assisted pyrolysis of oil palm shell was subjected to an attractive, environmentally friendly separation process, namely supercritical fluid extraction with carbon dioxide (scCO 2 ), to study the value‐added chemicals such as bio‐phenol. The operating parameters temperature and pressure were examined above the critical point of carbon dioxide. The yield of scCO 2 ‐oil extract tended to increase significantly with these two parameters according to one‐way ANOVA. The extract yield was within 63.09–67.72 %. The scCO 2 ‐oils were characterized for value‐added chemical components by GC‐MS and compared with the crude bio‐oil. Acids, as the dominant group of chemicals, were enriched by scCO 2 , and included dodecanoic acid, n ‐hexadecanoic acid, and octadecanoic acid. The thermal behavior of scCO 2 ‐oil was studied by thermogravimetry. The production cost of bio‐phenol extracted from scCO 2 ‐oil was estimated and compared with a commercial phenol product.