Banca de QUALIFICAÇÃO: KAREN GIOVANNA DUARTE MAGALHAES

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : KAREN GIOVANNA DUARTE MAGALHAES
DATE: 29/05/2025
TIME: 09:00
LOCAL: Auditório do NUPPRAR
TITLE:

Modeling and optimization of a system for hydrochloride production and hydrogen cogeneration

KEY WORDS:

Electrolysis, saline water, green hydrogen, life cycle analysis

PAGES: 55
BIG AREA: Engenharias
AREA: Engenharia Química
SUMMARY:

The increase in global energy demand, combined with growing pressure to reduce carbon dioxide (CO2) emissions into the atmosphere, is driving the search for technological solutions that are aligned with sustainable development.In this context, hydrogen (H2) can integrate various sectors of industry and the economy into the electricity sector, promoting the so-called decarbonization.Although there are several processes for producing H2, water electrolysis using renewable electricity has stood out in recent years.In this process, H2, known as green hydrogen (H2V) or low-carbon hydrogen, is produced in a more sustainable manner.Furthermore, given the recent discussions about the scarcity of drinking water, seawater, in turn, is an inexhaustible water resource and a natural electrolyte with great potential for application in the electrolysis process.Thus, saline waters are positioned as a possible solution for hydrogen production via electrolysis without competing with freshwater reserves.However, there are challenges in the direct application of saline waters in the electrochemical system due to the complexity of the effluent, the accelerated corrosion of the electrodes and the electrochemical competition between the Oxygen Evolution Reaction (OER) and the Chlorine Evolution Reaction (CER).In this context, this master's dissertation proposal aims to develop an electrochemical system using saline waters for the production of H2V and hypochlorite ions (ClO-).The electrochemical system consists of a cell equipped with a cationic membrane, a DSA electrode (Ti/RuO₂IrO₂TiO₂) acting as anode and a Ni-Fe-based stainless steel mesh operating as cathode.The set is powered by solar energy and operates in flow, with a control volume of 1 liter and duration of 2 hours.For the system modeling, an experimental planning was carried out using the central composite design (22) in synthetic NaCl solutions, with concentrations of 3500, 2500 and 1500 ppm and current densities of 25, 50 and 75 mA cm⁻².The ClO- conversion (in ppm) was evaluated as a response.In addition, in the system characterization, the volume of hydrogen produced, the stability of ClO- generated and the carbon footprint were analyzed, using the OpenLCA software.The results indicate that the estimated model for the electrochemical system presents a predictive capacity (R2 = 98.39 %, adjusted R2 = 96.79 % and predictive R2 = 89.75 %), from the results matrix the average and maximum deviations between the real and predictive hypochlorite ion conversion were 0.219 % and 2.418 %, respectively.The factors (linear, quadratic and interaction) that contributed most to the mathematical model were the linear terms with 77.01%, followed by the quadratic terms with 11.62% and the bidirectional interaction had a contribution of 9.77%.The response surface generated from the proposed quadratic model indicates that there is a zone in which the current density can be optimized to reduce energy consumption and maintain ClO production between 540 and 570 ppm, close to the maximum observed.The energy consumed by the system in the process varied with the increase in the applied current density, with averages of 0.012, 0.036 and 0.076 kWh.The faradaic efficiency of hydrogen produced also varied with the increase in the current density applied to the system, with averages between 79.05, 165.83 and 256.84%.Finally, based on the assessment of the system's life cycle, using the OpenLCA software, it was confirmed that the hydrogen produced can be considered green as it has a carbon footprint of 1.854 kg CO2 equivalent.

COMMITTEE MEMBERS:
Presidente - 2275848 - ELISAMA VIEIRA DOS SANTOS
Interno - 2941160 - JOSE HERIBERTO OLIVEIRA DO NASCIMENTO
Externo ao Programa - 1645110 - CARLOS ALBERTO MARTINEZ HUITLE - UFRNExterno ao Programa - 1752014 - EDNEY RAFAEL VIANA PINHEIRO GALVAO - UFRN