Desenvolvimento da carboximetil lignina como aditivo multifuncional para a indústria do petróleo: uma alternativa para o aproveitamento de biomassas lignocelulósicas
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...
Na minha lista:
Autor principal: | |
---|---|
Outros Autores: | |
Formato: | doctoralThesis |
Idioma: | pt_BR |
Publicado em: |
Brasil
|
Assuntos: | |
Endereço do item: | https://repositorio.ufrn.br/jspui/handle/123456789/28086 |
Tags: |
Adicionar Tag
Sem tags, seja o primeiro a adicionar uma tag!
|
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. |
---|