Banca de QUALIFICAÇÃO: JOSÉ VALDERISSO ALFREDO DE CARVALHO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : JOSÉ VALDERISSO ALFREDO DE CARVALHO
DATE: 29/01/2024
TIME: 10:00
LOCAL: LABCIM
TITLE:

SYNTHESIS OF LIGNIN-BASED BIOADTIVE FOR APPLICATION IN CEMENTING OIL WELLS

KEY WORDS:

Lignocellulosic biomass; lignin; natural additives; cementing; oil wells.

PAGES: 103
BIG AREA: Engenharias
AREA: Engenharia Química
SUBÁREA: Tecnologia Química
SPECIALTY: Cimento
SUMMARY:

Cementing plays a fundamental role in the construction of oil wells, as it is directly linked to their integrity and durability. A slurry used for this purpose is typically composed of water, cement, and additives. Additives are essential materials for adjusting the physical and chemical properties of the slurry, making it suitable for the peculiar temperature and pressure conditions found in wells. Additives can be synthesized from a variety of inorganic and natural compounds. One example is lignin, a polymer found in lignocellulosic biomasses that has low commercial value. However, when subjected to structural modification processes, it can acquire exceptional characteristics that make it highly valuable and suitable for a variety of industrial applications. Therefore, this research aimed to develop a bioadditive from the lignin of green coconut biomass, via oxidative modification with hydrogen peroxide, for application in oil well cement. To do this, the lignin from green coconut biomass was extracted by alkaline pretreatment and its structural modification was carried out through the oxidation process, using hydrogen peroxide. After the synthesis process, the unmodified lignin (UL) and the oxidized lignin (OL), were characterized by means of Zeta potentials, Fourier-transform infrared spectroscopy (FTIR), UV spectrophotometry, and thermogravimetric analysis (TGA/DTG). Lignins were validated as setting retardant additives through a thickening time test, and their dispersing capacity was studied as a secondary property through a rheological test. After validation, a technological application was carried out to better evaluate the behavior of the synthesized additive and compare it to a commercial additive, simulating the primary cementation of an oil well. Cement slurries were characterized by rheology, static filtration, and thickening time tests. Physicochemical characterization revealed some structural changes in OL promoted by oxidation, such as increased surface charges of particles, opening of aromatic rings, and increased carboxylate groups. OL showed better performance in retarding the setting of cement pastes than UL. A concentration of 0.5% of LOX was able to delay the setting time by more than 2 hours, validating it as a setting retardant additive. In addition, the rheological test showed that OL has a dispersing effect as a secondary property, being able to reduce the rheological parameters of cement slurries. The technological application showed that OL can modify the properties of cement slurries in a way that is compatible with a commercial setting retardant additive. The application of OL in conjunction with other additives promoted a small increase in the rheological parameters of the slurries and contributed to the reduction of filtrate. With respect to setting time, with only 0.1% OL, it was possible to delay the setting time of the slurry by 71 minutes. These results suggest that OL is a promising alternative retarding additive that, in addition to benefiting the oil and gas industry, contributes to adding value to the green coconut residue.

COMMITTEE MEMBERS:
Presidente - 1979301 - RENATA MARTINS BRAGA
Interno - 3304882 - CARLOS EDUARDO DE ARAÚJO PADILHA
Externo ao Programa - 1804366 - JÚLIO CÉZAR DE OLIVEIRA FREITAS - UFRNExterno ao Programa - 1995142 - RODRIGO CESAR SANTIAGO - UFRN