Banca de DEFESA: PAULO HENRIQUE SILVA SANTOS MOREIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : PAULO HENRIQUE SILVA SANTOS MOREIRA
DATA : 27/04/2018
HORA: 09:00
LOCAL: Labcim
TÍTULO:

CARBOXYMETHYL LIGNIN AS A MULTIFUNCTIONAL ADDITIVE FOR THE PETROLEUM INDUSTRY: an alternative for the use of lignocellulosic biomasses

PALAVRAS-CHAVES:

Carboxymethyl lignin, multifunction additive, retarder additive, scale inhibitor

PÁGINAS: 135
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Orgânica
ESPECIALIDADE: Química dos Produtos Naturais
RESUMO:

The thesis presents carboxymethyl lignin (CML) as a multifunctional additive for applications in the petroleum industry. The carboxymethylation reaction follows the classical reaction of Williamson ethers where an alkoxide (lignin alkali) is reacted with an alkyl halide (monochloroacetic acid) to form an ether. CML was evaluated as retardant additive for cement pastes and as a scale inhibitor additive. The studies on CML as a set retarder were performed with a lignin extracted from the sugarcane bagasse by the soda-anthraquinone method. The lignin derivative was added to the cement paste composition and tested in pressurized consistometry (API RP 10B) assays to determine the thickening time (setting time) of the tested pastes. The increase in the time of thickening of the cement pastes as a function of the addition of CML to the composition was observed. A second mechanism of action (besides the classic) for CML was proposed. Semi-empirical calculations were performed to simulate the ability of CML to form coordination complexes with Ca²⁺ ions fundamental to the cement set process. The proposed complex was entropically favorable in a spontaneous process with relation to Gibbs free energy. These observations about CML's ability to adsorb in the cement core and to complex Ca²⁺ ions motivated the study on scale inhibitor. For this work, the carboxymethylation reaction was applied to a lignin extracted from the wood by the Kraft method. CML was evaluated as a scale inhibitor in a synthetic system of produced water from oil field. Inhibition efficiency tests were performed by the dynamic method (dynamic capillary tube precipitation) according to the procedures of NACE 31105 and by the static method. The crystals formed by the static method were analyzed by scanning electron microscopy (SEM) and X-ray diffraction. It was observed that in the absence of CML the scale products were basically the polymorphs of CaCO3 with predominance of the polymorph aragonite with calcite in smaller proportion. In the presence of CML, the MEV images showed an inhibition of growth of aragonite and calcite rods as the major phase in the fouling products. XRD assays associated with Rietveld's refinement technique have confirmed that aragonite actually reduced its percentage in the inlay composition and the SEM images also show that crystal growth has been reduced by an order of magnitude. The results of the research show that the lignin carboxymethylation may be a technological alternative to add value to the lignocellulosic biomass residues and that its versatility can cover several sectors of the oil and gas industry.

MEMBROS DA BANCA:
Externo à Instituição - ERIKA PINTO MARINHO - UFPE
Externo à Instituição - FABIOLA DIAS DA SILVA CURBELO - UFPB
Presidente - 1804366 - JÚLIO CÉZAR DE OLIVEIRA FREITAS
Interno - 1149440 - ROSANGELA DE CARVALHO BALABAN
Externo à Instituição - ULISSES TARGINO BEZERRA - IFPB