Key words: lignin, 2D NMR structure, phenols, depolymerization, gasification, hydrogen production
Aqueous solutions of depolymerized lignin with a concentration of 12—15 g/l were obtained
by treating an aqueous suspension for 4 hours at 250 °C and 10 MPa. The transformation
of lignin in the resulting solution was studied at sub- (320 °C, 30 MPa) and supercritical
(400—650 °C, 30 MPa) parameters in a continuous flow reactor. It is shown that the
degree of lignin depolymerization increases with increasing temperature and reaches its
maximum value at 650 °C; the process results in the formation of hydrocarbons of
various groups, including derivatives of benzene and phenol. At temperatures above 600 °C,
intense gasification of lignin occurs with the production of gas mixtures containing up
to 40 vol.% hydrogen.