Banca de DEFESA: IÊDA LETÍCIA MENDES SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : IÊDA LETÍCIA MENDES SILVA
DATA : 09/11/2016
HORA: 14:30
LOCAL: AUDITÓRIO DO NUPEG
TÍTULO:

"CALCIUM CHLORIDE SOLUBILITY IN AQUEOUS MIXTURES OF ETHYLENE GLYCOL BY THE ANALYTICAL METHOD VIA DENSITY"

PALAVRAS-CHAVES:

Calcium chloride, solubility, MEG, density, conductivity, thermodynamic modeling.

PÁGINAS: 85
GRANDE ÁREA: Engenharias
ÁREA: Engenharia Química
RESUMO:

In the oil and gas industry, hydrates formation is one of the issues related to the natural gas production. One of the most employed techniques to avoid hydrates formation is the injection of inhibitors compounds, like the monoethylene glycol (MEG) into the well. However, MEG stream returns to the surface impregnated with water and many salts coming from the rock sediments. Then, MEG must be regenerated to assure process environmental and economic viability. In order to optimize the operationals conditions of the reclamation process, this work aimed to determine the solubility of the calcium chloride in aqueous mixtures of MEG, in the temperatures of 25 and 50°C. The proposed methodology is analytical and applies indirect properties, density and conductivity, to determine solubility data. Therefore, the main data were obtained from densimetry, conductimetry, and beyond them, thermogravimetry and Karl Fischer titration to verify purity and moisture content. Observing the developed curves of density and conductivity versus calcium chloride concentration, it was detected the monotone and linear behavior for the density as function of the salt concentration. However, for the conductivity, it was observed a no-monotone and non-linear behavior. Thus, in order to determine solubility data, samples were evaluated with the aid of concentration versus density calibration data. The developed isotherms illustrate the calcium chloride solubility versus MEG concentration behavior. The isotherms have demonstrated the slight relevance of the salting-out effect, caused by the MEG presence in the solvent, until an average concentration of 33% MEG (salt-free). From that point, there are changes in the inclination of both isotherms and the solubility decreases more pronouncedly. In terms of the temperature increase, the calcium chloride solubility showed a positive effect. Setchenov equation and UNIQUAC+DH model were applied to describe the experimental data. In the UNIQUAC approach, it was not considered the change in the solid phase expressed by the corresponding thermochemical data due to MEG concentration. In the other hand, similarly to Setchenov correlation, two set of parameters were estimated for each isotherm, considering each solid phase formed. The description provided by the UNIQUAC+DH resulted closed to the experimental uncertainty, i.e., in average 2.00 % for the calcium chloride solubility.

MEMBROS DA BANCA:
Externo à Instituição - EDSON LUIZ FOLETTO - UFSM
Externo à Instituição - ITALLA MEDEIROS BEZERRA - UFERSA
Presidente - 1149554 - OSVALDO CHIAVONE FILHO