Characterization of different wood species as potential feedstocks for gasification

This paper provides an extended overview of the chemical characteristics of 19different wood species originating from Estonia. The variation of chemical composition in woodand bark was investigated using a variety of analytical techniques including WD-XRF, ICP-MS,and elemental analysis. Principal component analysis (PCA) was used to observe clustering inthe sample set. It revealed a clear data clustering in terms of the wood and bark samples. Woodcharacteristics exhibit quite narrow ranges, on the other hand the composition of wood barksamples is significantly different and more distributed. The correlations and associations among27 chemical parameters, including 16 ash-forming elements, were studied. Several significantpositive correlations between Cr-Ni-Fe, Ca-Sr, Al-Na-Si-Ti, K-Mg-P, Fe-Zn-Cr-Ni-Cu, Ash-Ca,N-S-P and O-volatile matter were found. Most of the metallic components are negativelycorrelated with volatile matter, C, H, O and heating value and are positively related to each other,or no significant correlation was identified. Results are compared to literature data and technicalquality standards for biomass. Biomass feedstocks availability and composition for gasificationprocess was discussed. Wood samples had higher volatiles content than in bark which is anindication that higher conversion rate and lower gasification temperature can be used. Spruce,pine and black alder barks have higher fixed carbon content than other common species that mayincrease biochar yield. Commonly available woods like Scots pine, Norway spruce, aspen, birch,black alder and grey alder may considered as suitable feedstocks for gasification because of theirlow N, S, Cl, and ash content together with high volatile matter, however, relatively high totalheavy metals content were found from birch and grey alder barks compared to other hardwoods.