Lignin conversion to fuel and chemicals gets easier
The second most abundant natural organic polymer on earth, lignin is the first of those composed of aromatic monomer units. It can be a renewable source of valuable phenolic chemicals, if converted to smaller molecular units. Lignin represents a potential bio-based alternative to several petrochemical processes. New processes for producing high-purity lignin from wood have recently become commercial and in the years to come there will be a large amount of this biomaterial available for future biorefineries. Conversion in near-critical or supercritical water is among the most promising processes for lignin depolymerisation and conversion into fuel and chemicals. The EU-funded CRACKING OF LIGNIN initiative has developed a new lab-scale reactor for converting lignin into bio-oil and chemicals operating in high-pressure high-temperature water (hydrothermal conversion in near-critical water), and the accompanying operating procedure. The new reactor can produce more precise results than the currently available alternatives. Different to ordinary lab reactors for biomass hydrothermal conversion, the new reactor allows direct injection of the biomass in the reacting chamber at high temperature and high pressure. In addition, it allows a fine pressure regulation and the possibility of withdrawal and rapid quenching of the products. These features enable biomass reaction at the desired high-temperature and high-pressure for an exact reaction time. CRACKING OF LIGNIN developed an operating procedure for efficient use of the new equipment obtained during the study period. Project work produced results far more reliable than those typically obtained with common commercial turnkey batch reactors available on the market. The new reactor will enable production of accurate experimental data for the hydrothermal conversion of lignin in near-critical water, shortening the time for the development of this intriguing technology at industrial level.
Keywords
Lignin, fuel, lignin depolymerisation, CRACKING OF LIGNIN, near-critical water
