Elucidation of the interaction among cellulose, xylan, and lignin in steam gasification of woody biomass

Abstract

in Wiley InterScience (www.interscience.wiley.com).The reaction mechanism for gas and tar evolution in the steam gasification of cellulose, lignin, xylan, and real biomass (pulverized eucalyptus) was investigated with a continuous cross-flow moving bed type differential reactor, in which tar and gases can be fractionated according to reaction time. In the steam gasification of real biomass, the evolution rates of water-soluble tar (derived from cellulose and hemicelluloses) and water-insoluble tar (derived from lignin) decrease with increasing reaction time. It was found that the evolution of water-soluble tar occurs earlier than in the gasification of pure cellulose, indicating an interaction of the three components. The predicted yield of water-insoluble tar is substantially less than that of real biomass. This implies that the evolution of tar from the lignin component of biomass is enhanced, compared with pure lignin gasification, by other components. The gas evolution rate from real biomass is similar to that predicted by the superposition of cellulose, lignin, and xylan.

Elucidation of interaction among cellulose, lignin and xylan during tar and gas evolution in steam gasification

“…It was found the evolution of water-soluble tar which is mainly evolved from cellulose component in real biomass takes place earlier compared with the evolution profiles of water-soluble tar in the gasification of pure cellulose. These results indicate the existence of interaction among cellulose, lignin and xylan during tar production and evolution [4]. If the detailed reaction mechanism of the interaction is clarified, it would be possible to control the tar evolution in pyrolysis and gasification of biomass by using the interaction.…”

“…The detail of the continuous cross-flow moving bed type differential reactor (CCDR) was described in our previous papers [3,4]. The reactor consists of a quartz glass half tube covered with a quartz glass plate and a conveyor belt system.…”

“…The elemental compositions of these samples were shown elsewhere [4]. Each sample was dried at 333 K in an oven for 12 h. Xylan was sieved and the fraction under 180 mm was used.…”

“…Recently, we have developed a continuous cross-flow moving bed type differential reactor (CCDR) to investigate the time profile of gas and tar evolution with a differential analysis method under continuously sample feeding condition [3,4]. Using the CCDR, steam gasification of cellulose, lignin, xylan, and real biomass (pulverized eucalyptus) was investigated at 673 K. It was proven that in real biomass gasification the gas evolution rate is similar to that predicted by superposition of those for cellulose, lignin, and xylan.…”

Numerical Simulation of the Thermal Degradation of Biomass – Approaches and Simplifications

“…In reality, such interactions do exist between reactive components; however, they may be more or less expressed. These interactions were not only recognized, their systematic investigation was also reported [10,11]. However, the errors introduced by the application of the segregation principle did not exceed the ones caused by other simplifications and/or factors, for example, the distorting effects on kinetics by the presence of inorganic impurities (primarily salts) [12].…”