Sampling is a vital part of the test procedure. If the tested oil sample is not representative of the whole batch to be treated, the conclusions drawn during the test procedure may be invalid. Samples should be taken from the top, middle, and bottom then mixed thoroughly. Ideally, a sample should be taken after mixing the entire contents of the storage tank. Separate samples should be taken at regular intervals from the pipeline during transfer of the oil.

Sample size needed: 1 - 2 gallons (normally)

Normal (waste in oil), or reverse (oil in water) emulsion?

After thoroughly mixing the sample, pour a few drops of oil into two beakers filled with toluene (or gasoline) and water respectively. If the drops readily dissolve in the water, then an oil-in-water emulsion exists. Alken 862 Demulsifier may work less effectively with this type of emulsion. If the sample readily dissolves in solvent, then it is of a normal water in oil (water in oil) emulsion.

Determine the specific gravity of the oil, preferably at 15°- 20°C, otherwise at ambient temperature. The difference in specific gravity of the oil and the dispersed water phase determines the settling speed of the water and consequently the length of the bottle test procedure and actual treatment time. In case of high BS &W values, a correction should be made to obtain the actual specific gravity of the oil phase.

Settling times estimated for certain specific gravities of the oil phase: (i.e. specific. gravity H2O = 1). Viscosity of oil, tightness of emulsion, temperature, temperature drop, tank size, and tank form can all contribute variability to these estimates.

Determine the BS & W by the centrifuge method (sample diluted 1/1 with toluene or gasoline) with addition of 1 drop of Alken 862 Demulsifier.

While running the above test, run a simultaneous blank test, without the addition of Alken 862 Demulsifier. This will give an indication of the tightness of the emulsion. Determine the water content of the sample by distillation. If determined on a weight basis, convert the water content on volume basis.

The difference between BS & W and water content (both on volume basis) equals the BS content. Normally this amount is 1-4%. Generally a BS content of more than 4% is considered high. In such cases, a higher chemical injection is needed.

Required equipment:

• Waterbath or Oven
• 5 x 1 liter graduated flasks or 5 x 1 L graduated centrifuge tubes
• Micro-pipetter adjustable to deliver 0.05, 0.075 ml, 0.1 ml and 0.25 ml

Fill the test bottles up to just below the 1 L mark and heat the samples to a temperature of about 20°F lower than the temperature that can be achieved in the actual facility. This takes into account the temperature drop that will occur during the actual treatment, even when the tank is perfectly insulated.

Inject by means of the syringe, 0.05 ml, 0.066 ml, 0.1 ml and 0.25 ml of Alken 862 Demulsifier into each of 4 flasks of waste solution. These dosages correspond to 1:20000 (50 ppm), 1:15000 (75 ppm), 1:10000 (100 ppm) and 1:5000 ratios. Leave one jar untreated as a "control".

Thoroughly mix in the chemical by shaking the bottles for about 20 seconds or 1 minute stirring (with magnetic stirrers). Place the sample bottles in the waterbath or oven and note at regular intervals the amount of free water and/or the level of the separation between oil and interphase. Because Alken 862 Demulsifier will separate the solid particles, salt and sulfur from the oil, into the water phase, the separated water and the interphase may, on occasion, be colored as black as the oil. If this occurs, viewing through a strong light may be necessary to observe the separation.

Allow the samples to stand in the waterbath or oven overnight and note the positions of the dividing lines that occur between oil layer, emulsion layer and water layer. When there are no further changes in the widths of the oil and water layers, note the time needed to reach this equilibrium. Compare the samples against each other to decide the minimum dosage of Alken 862 Demulsifier needed to provide optimum separation. Usually the layers reach equilibrium in two to four days.

If there is a significant emulsion layer or there is less than satisfactory separation by seven days time, in all the samples, consider retesting with higher and lower dosage series and also try repeating the test with 60 degrees C heat added.