Investigation On Hydrothermal Treatment Of Macroalgae Laminaria Japonica

Macroaglae is a kind of biomass, and always regarded as a kind of renewable resources. Its production is very large. At present, there are many ways to utilize the macroaglae. But high moisture content and high salt content limit the application of the macroaglae. Hydrothermal treatment provides an effective method for the reutilization of macroaglae. Laminaria japonica as a kind of macroaglae has a large amount of carbohydrates, a small amount of lipid and crude fiber. Laminaria japonica was treated using hydrothermal carbonization and liquefaction. The products of hydrothermal carbonization and liquefaction were analyzed to reveal the mechanism of transformation. At the same time, the prospect of high value products were investigated in this study. The detailed conclusions of this study were drawn as follows:(1) The reaction temperature had significant influence on hydrothermal products. The result showed the highest carbon content and HHV of solid product made from raw material got at 240℃. The carbon content and energy density of solid products made from raw material with salt were increased by 20.64% and 116%, the solid products recovery was 18.83%. But the carbon content and energy density of solid products made from raw material without salt were only increased by 14.36% and 51.41%, and the solid product recovery was 23.92%. So, salt can promote the decomposition of the raw material. The solid recovery became lower and lower, carbon content and energy density were significantly increased.(2) The surface of hydrothermal carbonization products had rich and irregular pore structure. After activation of solid products, the surface area could reach more than 1000 m2/g. At the same time, FTIR analysis showed that the solid products contained abundant oxygen and nitrogen functional groups. Solid products could be made into high quality materials.(3) As the reaction temperature increased from 280℃ to 320℃, Carbon monoxide production yield was steady at 13.84～13.95 CO mL/g, hydrogen production yield was increased from 1.61 to 2.91 H2mL/g.19.32% of the highest bio-oil yield was got at 300℃. The bio-oil which produced by my experiment has complex component, included ketone substance, pyrrole substance, pyridine substance and pyrazine substance.