Empirical modeling is considered from the perspectives of a general scheme for the Strategy of Empirical Research and Optimization Process (SEROP). This approach intends to facilitate the understanding of the necessary steps to arrive to mathematical models able to appropriately describe the behavior of a group of controllable independent variables related to a certain response. Aspects connected with definition of the problem, variable’s identification and optimization stages are discussed. As an example of SEROP application, it is presented the empirical modeling of the basic extraction of alginic acid from brown algae.

Brookfield R.V.T. apparent viscosity measurements of 31.1 to 73º Brix vinasses, with and without nondissolved solids (N.D.S.), were carried out at varying rotation speeds (N) and temperatures (T). A regression analysis of this data was carried out to select the corresponding mathematical models. It was concluded that apparent Brookfield viscosity for low concentration vinasses (up to 52.4º Brix) depends only on linear and quadratic temperature terms. At higher concentrations (66º and 73º Brix) regression models for apparent viscosity, must also include quadratic as well as rotation speed-temperature interaction terms. This behavior is discussed, identifying two types of rheological behaviors and advancing a preliminary hypothesis about the role of solutes, N.D.S. and temperature.

This work presents a method to conduct a thermodynamic analysis of sugarcane bagasse boilers. The method is based on the standard and actual reactions which allows the calculation of the enthalpies of each process subequation and the exergies of each of the main flowrates participating in the combustion. The method is presented using an example with real data from a sugarcane bagasse boiler. A summary of the results obtained is also presented together based on the 1st Law of Thermodynamics analysis, the exergetic efficiencies, and the irreversibility rates. The method presented is very rigorous with respect to data consistency, particularly for the flue gas composition.

Vinasse, a residual substance left after sugarcane alcohol distillation, represents a major environmental problem for the ethanol industry. No one has found a convenient and economical disposal solution for this black-reddish (Vinasse presents a light brown color and a low total solids content, from 2-4%, when it is obtained from straight sugarcane juice and a black-reddish color and total solids ranging from 5-10% when it is obtained from sugarcane molasses, which is the case of the vinasse used in this study.), viscous, high B.O.D. and acid material which is produced in quantities up to 15 times larger than those of the alcohol itself. This research investigated and developed the basic technology of on-site disposal of vinasse by combustion. Besides the clean ecological benefit, this method promotes energy savings and extra benefits when rich potassium vinasse ash is commercialized. Basic research was conducted using the facilities in the Combustion Laboratory (Mechanical Engineering Dept. at the Louisiana State University Campus in Baton Rouge). This research on vinasse combustion consisted of determining heating values, composition, and flame characteristics through combustion tests. Initially only vinasse was used in different solid concentrations and later emulsions were prepared using vinasse and # 6 fuel oil