Biofuel consisting of wheat straw–poplar wood blends: thermogravimetric studies and combustion characteristic indexes estimation

Renewable energies can play an important role reversing the current fossil fuels dependence. Among these, biomass is finding more uses consolidating itself as the energy of the future. Current trend is focused on the manufacture of new blends able to achieve a better use of this biomass. The aim of this paper was to assess the potential as fuel of a series of blends consisting of wheat straw and poplar wood fertilized in organic way. Different poplar clones were fertilized with two organic amendments derived from sewage plants. Thus, the effect of clones and fertilization on the thermal behavior of the blends was studied. For this purpose, fuel and thermogravimetric analysis as well as combustion characteristic indexes were used. Results denoted acceptable fuel analysis values. Thermogravimetric profiles showed three mass losses related to volatiles (550 K and 650 K) and char (700 K) liberation. The greatest mass release for blends occurred for the first stage. In particular, the blend consisting of AF8 poplar clone without fertilizer together with straw was the one that experienced this greater release. In the same way, thermal indexes warned of better thermal behavior when fertilizer was not applied; being, again, the blend mentioned above, the one that achieved the best indexes values. Thus, fertilization decreased the thermal performance of wheat straw–poplar wood blends.