Parametric optimization and statistical evaluation of a spray dryer for the evaporation of caustic soda solution

Abstract

Optimum evaporation of a 50% w/w caustic soda solution with a spray dryer was investigated in this work to enhance performance and statistically evaluate process parameters. Application of suitable model with validation, fabrication and operation within predicted optimum values enabled high performance, productivity and energy conservation. The highest exit mass flow rate of NaOH was 0.0459 kg/s, depicting 12% better value than the computed optimum value. The highest value of 73.85% was obtained for the exit final NaOH weight percent. Improvement over conventional multiple effect evaporators to obtain 73% w/w NaOH solution resulted in energy savings of about 2.34 106 J/kg (about 99.6565% specific energy savings). Statistical evaluation of process parameters using Analysis of Variance (ANOVA), Bonferroni-Holm, Holm-Sidak and Tukey Posthoc parametric tests enabled the confirmation of significant relationships among operating variables. The outcome indicated the possibility of better attainments in the field.