No abstract

No abstract

No abstract

The prediction of the ash behavior in combustion processes is enhanced by the determination of the ash-forming matter in the fuel. The scope of this work was to characterize Scandinavian wood fuels by studying the wood, bark and leaves from a spruce and an aspen. Chemical Fractionation, a step-wise leaching procedure that treat the fuel in water, ammonium acetate and hydrochloric acid, was used to determine the solubility of the ash elements. The resulting solutions were further analyzed on ionic species, which was coupled to the presence of salt compounds in the original biomass tissues. The leaching procedure dissolved nearly 100% of the ash-forming matter. The phosphorus (P), chlorine (Cl) and some of the sulfur (S) were readily leached with water and found present as HPO42−, SO42− and Cl− in the solutions. The simultaneous dissolving of potassium (K) in this step proved the presence of water soluble potassium salts in the biomasses. The remaining K after the water treatment and all magnesium (Mg) dissolved completely in the ammonium acetate step together with a large part of the tissues’ calcium (Ca) and manganese (Mn). The remaining Ca after the second step was leached in hydrochloric acid together with equivalent amounts of oxalate ions, C2O42−. This proved the presence of acid soluble calcium oxalate in the tissues, a salt with low solubility in neutral pH.

The Nordic countries have a long tradition of utilizing agro-industrial sidestreams for heat and power production and recovery of chemicals. A typical example is black liquor from pulp mills. Here, the woody biomass undergoes a digestion process where the fibers are separated to produce pulp for paper production. The liquid by-product from the digester, black liquor, contains wood lignin and the spent cooking chemicals. Through the chemical recovery cycle, the black liquor is utilized for heat and power production and recovery of cooking chemicals. Worldwide, there are several challenging biomass sidestreams that can be utilized in a similar fashion as with black liquor. Some examples of these are vinasse from the integrated sugar-ethanol production process; straw and manure from agriculture sources; forest residues; by-products from the food industry; etc. This book chapter will review the availability of these types of feedstocks and discuss their applicability and challenges to be used for energy and chemicals. Pyrolysis, gasification, and combustion are the potential thermal conversion options considered for the utilization of these types of challenging biomass feedstocks.