In this equation,A_fa has been considered equal to1 (Eq. (8)) taking into account the experimental results and calculations, with a high confidence level.
It can be observed that the above simplifications to calculate for q_4 andq_5; reduce and simplify the number of statistical models to be fitted to obtain the claimed efficiency chart. In the next paragraph, the statistical models fitted to calculateC_uf; CO/(CO + 〖CO〗_2) and stack temperature, T_eg; will be discussed. It should be noted that the last parameter, Teg; is needed to calculate the exhaust gases enthalpy in Eq.2
In order to obtain a simplified model, the influence of the stoichiometric ratio in the furnace (∝_f ) a and steam power (D_sh ) on the unburned carbon in the fly ash, C_uf; has been plotted. Results of the experimental measurements are depicted in Fig. 2. As can be seen, the unburned carbon increases with increasing steam power and decreases with increasing stoichiometric ratio in the furnace. As steam power is raised at a constant stoichiometric ratio, both the amount of bagasse fed and the combustion air flow rate increase, since the air volumetric flow rate per unit weight of bagasse is fixed. This, in turn, increases the average gas velocity in the furnace and the fraction of fuel that burns in suspension, rather than in the bed on the stationary grate. The shorter residence time available for combustion in suspension results in an increased unburned carbon carryover and poorer combustion performance.
Therefore, when steam power and bagasse consumption are increased, a higher stoichiometric ratio in the furnace is needed to achieve the same carbon conversion ( C_uf): Taking into account all the experimental data, a statistical model is fitted