Banca de DEFESA: ROSANGELA DALA POSSA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : ROSANGELA DALA POSSA
DATA : 06/07/2018
HORA: 08:30
LOCAL: Auditório PPGEQ
TÍTULO:

Influence of the treatment of the char from the pyrolysis of the sewage sludge on the purification of a methane-rich gas mixture that is similar to the gases obtained from the fermentation of swine manure.

PALAVRAS-CHAVES:

Methane purification; sewage sludge pyrolysis char; adsorption capacity; breakthrough curve; fixed-bed column; adsorption model.

PÁGINAS: 97
GRANDE ÁREA: Engenharias
ÁREA: Engenharia Química
SUBÁREA: Processos Industriais de Engenharia Química
ESPECIALIDADE: Processos Orgânicos
RESUMO:

Biogas is a valuable source of renewable energy because it is composed mainly of methane (60-80%), carbon dioxide (20-40%), and traces of ammonia and hydrogen sulfide. The main application of biogas is the use of methane as fuel for electric motors and generators. In order to increase the calorific value of biogas to the same level as that of methane, the other gases have to be removed. One of the most common processes used to purify biogas is adsorption using activated carbons. The objective of this work was to the study the adsorption of carbon dioxide, ammonia, and hydrogen from a mixture with the same composition as that of the biogas from the fermentation of swine manure. The adsorbent used was the char from the pyrolysis of sewage sludge at 500 °C. The chars underwent physical ativation (at 700 °C, for 2 hours, under N₂), chemical activation using HCl (7.5 M) or KOH (3.0 M), and were characterized for composition and textural properties via XRD, XRF, BET, and SEM. The experiments were carried out in a fixed-bed column (adsorber) at 25 °C and 1 atm. The gas flow rate was 50 mL/min, and the mass of char were 18.4 or 6.0 g. The results showed that the chemical activation significantly enhanced the adsorption. Regarding the adsorption of H₂S and CO₂, the best result was for the char treated with HCl. The char had high specific area (248 m²/g), high breakthrough time (400 min for H₂S, and 175.5 min for CO₂), high saturation time (1020 min for H₂S, and 484.5 for CO₂), and high adsorption capacities (670,33 mg H₂S/g_ads e 218.385 mg H₂S/g_ads). The chars were selective for NH₃ and had no affinity for CH₄. The percentages of adsorption were 61,4% for H₂S and 75% for CO₂ using HCl. For the gas mixture, the percentages of adsorption were 71,8% for H₂S and 55% for CO₂. The dynamic adsorption was modeled by a system of differential equations describing mass balances for gas and particle phases. The equations were solved numerically against experimental data (molar fraction) in order to obtain estimates for parameters such as axial diffusivity, effective intraparticle diffusivity, and external mass transfer coefficient for H₂S and CO₂ as well as others present in the mixture involving NH₃ and CH₄.

MEMBROS DA BANCA:
Presidente - 350247 - JOAO FERNANDES DE SOUSA
Externo ao Programa - 2415657 - ANDREA OLIVEIRA NUNES
Externo ao Programa - 1805556 - LUCIENE DA SILVA SANTOS
Externo ao Programa - 2668814 - MAGNA ANGELICA DOS SANTOS BEZERRA SOUSA
Externo à Instituição - FRANCISCO WENDELL BEZERRA LOPES - UnP
Externo à Instituição - JUAN ALBERTO CHAVEZ RUIZ - CTGás