Demulsification efficiency of the leave extract from African blackwood (Delbergia melanoxylon)

Abstract

The demulsification efficiency of the leave extract from African Blackwood (Delbergia Melanoxylon) was determined using the bottle test method. Methanol, n-heptane and distilled water were used as extraction solvents respectively to extract the active ingredients of the leave. A 200 ml crude oil emulsion obtained from Niger Delta area Nigeria was introduced into six (6) calibrated 500 ml Teflon-stoppered bottles respectively, the leave extract in the solvent was introduced into each of the bottles as a demulsifier at concentrations of 50, 100, 150, 200 and 250 ppm with the sixth bottle left as control (without demulsifier). All the bottles were immersed in a water bath of 60 0C after mixing properly with a mechanical laboratory mixer and left for an hour. After an initial 5 minutes, the percentage of water separated in each bottle was recorded after 10 minutes. Bottle test was also carried out using a synthetic demulsifier (DXO77) on the same crude oil. Results obtained shows that the leave extract using methanol had the highest demulsification efficiency separating 50.5 % water from the crude after 60 minutes with a demulsifier concentration of 250 ppm. A 250 ppm of the synthetic demulsifier (DXO77) separated 51.0% of water from the crude after 60 minutes. The leave extract using n-heptane and distilled water separated 40.5 % and 32.5% water from the crude after 60 minutes at demulsifier concentrations of 250 ppm respectively. There is a consistency in the percentage of water from the crude within the last 15 minutes indicating that the separated water in the crude has reached its threshold, further increase in the demulsifier concentration at this point could lead to emulsification. The demulsification efficiency of plant extracts such as African Blackwood (Delbergia Melanoxylon) are influenced by the characteristics of the extraction solvent such as solvating power and extraction capacity.