Banca de DEFESA: MÁRCIA FERNANDA TEIXEIRA DE MENEZES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : MÁRCIA FERNANDA TEIXEIRA DE MENEZES
DATE: 19/02/2022
TIME: 10:30
LOCAL: meet.google.com/caw-xcyx-mjw
TITLE:

FRACTIONARY CRYSTALIZATION STRATEGY APPLIED TO THE NACL-CACL2-H2O SYSTEM

KEY WORDS:

Groundwater. Fractional crystallization. Solid-liquid equilibrium of the NaCl-CaCl2- H2O system..

PAGES: 73
BIG AREA: Engenharias
AREA: Engenharia Química
SUMMARY:

The Brazilian semi-arid region, in certain periods, suffers from water scarcity. In addition to insufficient rainfall, another factor that contributes to this scenario is the presence of shallow crystalline soils, which impair water storage in underground aquifers. However, even if stored in high amounts in aquifers, due to the high amount of salts, the water becomes unfit for human consumption. According to Ordinance 2,914/2011 of the Ministry of Health, in the long term, water with a high amount of ions in solution may lead to health complications for individuals who consume it. To solve this problem, the use of desalination techniques is recommended. The present study was carried out based on physical-chemical data from well water in the community of Boa-Fé in Mossoró/RN, based on data collected by Antas (2017), and a strategy for recovering salts and obtaining drinking water. A fractional crystallization study was then carried out based on solid-liquid equilibrium diagrams, applied to the NaCl-CaCl2-H2O system at different operating temperatures (50 °C and 75 °C). The first stage of the project was based on the study of the system at 75 °C, from which it was possible to define crystallization routes (Strategy A1, B2, C3, and D4). In this condition, the route that showed the best performance in removing the salts was Strategy B2, which showed extraction of 83.85% of NaCl and 72.16% of CaCl2.2H2O. Even though the percentages were high, they were not enough to bring the system to the value established for the potability standard. It was, therefore, necessary to start the second stage of the study, in which optimization strategies were defined that would lead to greater recovery of these salts: cooling the process to a temperature of 50 °C (Optimization 1); dilution of the output current to the system at 75 °C (Optimization 2); the dilution of the output current for the system cooled from 75 °C to 50 °C (Optimization 3). Strategy B2 plus Optimization 2 proved to be sufficient to obtain water within potability standards. This strategy resulted in a recovery of 95.48% of NaCl and 92.20% of CaCl2.2H2O. However, among all of them, the one with the best recovery rates was Strategy B2 plus Optimization 3, which extracted 97.09% of NaCl and 94.82% of CaCl2.2H2O. In a third moment, the simulation of the fractional crystallization process was carried out in the SPECS v5.63© program, to compare the methodologies and validate the strategy established through the equilibrium diagrams. However, the thermodynamic model extended UNIQUAC and the equation of state SRK, used by the program, are not suitable to describe an electrolytic system. For this reason, the comparative study carried out revealed a significant difference between the methods, of approximately 11.15%. In conclusion, it was found that the study proved to be effective in proposing strategies for recovering salts and obtaining water within potability standards.

BANKING MEMBERS:
Presidente - 2929066 - ANDRE LUIS LOPES MORIYAMA
Interno - 349801 - CARLSON PEREIRA DE SOUZA
Externo à Instituição - FRANCISCO WENDELL BEZERRA LOPES - UnP
Externa à Instituição - INDIRA ARITANA FERNANDES DE MEDEIROS - UFRN