Investigations into the effect of cellulose and lignin on the co-combustion characteristics of coal and biomass

The effect of cellulose and lignin on the co-combustion characteristics of coal and biomass has been investigated by using a thermo-gravimetric (TG) analyzer. In this study, one typical Chinese sub-bituminous coal, HS coal, and two types of biomass, Sawdust (SD) and Straw (SW), were selected as the test samples. The main compositions of cellulose and lignin contents for sawdust and straw were analyzed chemically. Based on the main composition results obtained, the experimental results for the actual biomass samples are compared with those for the simulated biomass, which is made of the mixture of the cellulose with lignin chemical. In the TG experiment, the sample was heated from 25 degrees C to 1200 degrees C at the heating rate of 20 degrees C/min and the coal to biomass (including actual and simulated biomass samples) ratio was constantly kept at 50%:50% (wt%:wt%). The results show that straw and sawdust both contain more cellulose than lignin. With the increase of the cellulose content in the samples, the reaction rate and mass loss increases. The cellulose component contains lots of volatile matters which can be released at lower temperature and brings about many fibrous and porous structures during co-combustion, being good for improving the combustion characteristics of coal. Different components of cellulose and lignin in the biomass can result in their different char structures. It is also an important factor that may influence the co-combustion characteristics of coal and biomass.