Characterization of Aqueous Products Obtained from Hydrothermal Liquefaction of Rice Straw: Focus on Product Comparison via Microwave-Assisted and Conventional Heating

Abstract

This paper focuses on the comparison of aqueous products obtained from hydrothermal liquefaction (HTL) of rice straw via microwave (MW)-assisted and conventional heating treatments. A systematic investigation of HTL experiments of rice straw via MW-assisted and conventional heating treatments has been carried out, covering a broad but mild temperature range from 150 to 230 °C at 20 °C intervals. In addition, different reaction times were studied when the HTL reaction temperature was 210 °C. In comparison to conventional HTL, considerable aqueous products could be obtained for MW-assisted HTL, which consumes less time, and in addition, repolymerization behavior could be efficiently decreased and high saccharide yields could be obtained with MW-assisted heating. Besides, the HTL temperature appeared to be the dominant factor, while the increased residence time slightly changed the contents of total organic carbon (TOC) and typical sugars and acids for both conventional and MW-assisted HTL heating.