ABSTRACT
Gasication is a thermal biomass conversion process. At an elevated temperature, a controlled amount of oxidant reacts with the biomass to generate a low caloric value (LCV) and combustible synthesis gas. The synthesis gas comprises primarily carbon monoxide and hydrogen. This gas is also termed “syngas” or “producer gas.” For proper operation of a gasier, it is necessary to know the exact amount of air that will be used during the conversion process. The elemental composition of the biomass (that is to be gasied) must be known in order to determine the process stoichiometry. This can be accomplished by evaluating the ultimate analysis of the biomass. Data already available for certain feedstocks may be used for determining the amount of air needed for the gasication reaction to proceed. For example, from the elemental composition and ash content given for sorghum feedstock (see Table 10.1), the number of moles of each particular element can be determined by dividing the dry weight percentage by its atomic weight. The mole ratio of the elements C, H, O, N, and S in sorghum stalks can thus be obtained to arrive at a “chemical formula” for sorghum stalks, which can be used as a basis to estimate the air-to-fuel (A/F) ratio from the stoichiometric calculations.
