Tese
Análise exergética e o uso eficiente de recursos em processos biotecnológicos : modelagem e otimização de variáveis de processo
Fecha
2021-12-17Autor
Suzimara Reis da Silva
Institución
Resumen
Exergy analysis is a useful tool to assess the sustainability of biotechnological processes. The
application of exergetic analysis as a strategy for the study and selection of process variables is
still little explored in the field of biotechnology. Knowledge of the standard chemical exergy
of the compounds involved in the studied system is usually necessary for the analysis. However,
the calculation of this thermodynamic property, in many cases, is not trivial, since there is still
a limited number of thermodynamic data available in the literature for biocompounds.
Therefore, this thesis presents a proposal for decision-making on operating conditions of
bioreactors based on exergy. Initially, an analysis of the standard chemical exergy prediction
models commonly applied in exergetic analysis studies was performed. This analysis was
divided into three stages. The first stage aimed to carry out a bibliographical survey on the
property prediction methodologies commonly used for biotechnologically relevant compounds.
In the second stage, the most promising prediction models applied to biocompounds were
investigated in more detail. The prediction performance was evaluated for models based on the
group contribution method and for a semi-empirical correlation that considers the complete
combustion of the compound in question and empirical database. In the third step, hybrid
models for prediction of specific chemical exergy for pure organic compounds and
macromolecules of biotechnological relevance were proposed. Finally, an exergetic analysis of
the xylitol production process was carried out as a strategy for decision-making on more
productive and sustainable operating conditions for the bioreactor. The results obtained showed
that the GC-based method presented better statistical performance, presenting an adjustment of
equal to 0.98, mean absolute error of 0.56 MJ.kg−1 and mean relative error of 4.21%. The
proposed model for property estimation showed values and mean relative error of 99.41%
and 2.30%, respectively. Regarding the exergetic analysis, the proposed methodology proved
to be a useful tool for the development of fermentative systems for the production of xylitol
from the point of sustainability.