Extracted and powdered rhizophora mucronata tannin as deflocculant in drilling fluid formulation / Ahmad Hafizan Muhammad Muhayyidin

The application of tannin in drilling fluid after extraction and powderization from Rhizophora mucronata barks as deflocculant was investigated in this study. Tannin was extracted using Soxhlet extraction and boiling with variation of several parameters such as type of solvent used, time of extraction, and sample size. Powderization of the liquid extractant was conducted after extraction process using spray dryer and vacuum rotary evaporator. The percentage of extractives and the characterization of condensed and hydrolysable tannins were quantified before and after powderization. Rheological and filtration performances of water-based drilling fluid (WBDF) before and after hot-rolled with powdered tannin were conducted. Different weight of tannin (0, 2, 4, 6 and 8 g) was added into WBDF and the prepared samples were tested at 3 different temperatures namely 250, 300 and 350 °F. Results demonstrated that extracted tannin from Rhizophora mucronata bark with water for six hours was approximately 29 wt% and 13wt % for both Soxhlet extraction and boiling respectively. The Soxhlet extraction method was superior compared to boiling due to higher percentage of extractives. The optimum parameters for the Soxhlet extraction were using water at six hours extraction with 0.5 mm particles size of milled bark that able to extract 29 wt% of extractives. However, there is limitation on Soxhlet extraction as compared to boiling whereby the volume of solvent used in Soxhlet extraction (200 ml) is lower than boiling (1500 ml). The condensed tannin from Soxhlet extraction and boiling were 75.35 and 71.47 wt% respectively, while hydrolysable tannin were 0.00133 and 0.00117 wt% respectively. The extracted powdered tannin obtained by spray drying decomposed at higher temperature than those extracted using rotary evaporating i.e. at 270 °C. It is indicated that the powdered tannin extracted from spray drying was higher in thermal stability due to high crystallinity peak appeared from X-ray Powder Diffraction (XRD) analysis. Powdered tannins from spray drying and rotary evaporator contained 27.8% and 26.5% condensed tannins respectively and 0.001% hydrolysable tannins. The rheological properties after hot-rolled seems to be lower than before hot-rolled except for 8 g tannin. No flocculation occurred due to the anionic condition provided by hydroxyl ions in the tannin that neutralized the positively charged at the edge of clay particles. At higher temperature, tannin absorbed extra heat and prevented water molecules from forming hydrogen ions. This suggested tannin able to withstand high temperature condition. The filtration properties were also improved with low filtrate volume and thin filter cake due to bridging between negative-charge faces of the clay particles and the tannin molecules. The optimum weight was achieved at 6g of with the highest percentage reduction in rheological and filtration properties of 33.3 and 69.2 % recorded respectively