Written by Rickdatech

Testing for water in your WVO and Biodiesel never was this accurate! This test measures the total water content of oil, measuring both suspended and dissolved water. ASTM D 2709 only tests for suspended water, making this test more accurate than the official ASTM test for water. Water content can be measured over a range of 50 ppm to 15,000 ppm with a resolution of 20 ppm water. ASTM specification is that water and sediment not exceed 1500 ppm.

The test works by chemically reacting the water with calcium hydride to produce hydrogen gas. The reaction takes place in a closed container creating a pressure. The pressure inside the closed container is chemically calibrated to read in water content directly. The test kit comes with the pressure vessel shown below. The kit costs $250, the reagents cost approximately $1.00 per test.

We have seen cases in blending where both the biodiesel and the diesel fuel were dry and clear, but became cloudy when mixed. Dissolved water is evenly distributed throughout the fluid and clear in both diesel and biodiesel. Water in suspension is in the form of tiny bubbles of water suspended. If the concentration of water exceeds the amount the fluid is capable of dissolving it will become turbid or cloudy. Biodiesel can hold more water dissolved than diesel and when they are blended, the blend is able to dissolve water in the same amounts as diesel. If both the biodiesel and the diesel are near saturation (or the point at which adding more water makes the biodiesel or diesel go turbid) when blended the blend can become cloudy. This entire issue is not measurable with ASTM specified testing. The Sandy Brae Water Test Kit can measure the total water content of both biodiesel and diesel before blending ensuring a perfect blend every time.

Before making biodiesel the water content of the WVO has a strong influence on how much soap is made. When using liquid catalyst even undetectable dissolved water in the WVO can cause the reaction to cascade and make a processor full of soap.

Many of us have a jar of biodiesel that gets turbid at night when the temperature drops, but clears up in the daytime as the temperature rises. Warm biodiesel can hold more water dissolved than cold biodiesel, so testing for water becomes important in winter when the temperatures can drop low enough to cause water to form water bubbles that can harm your Injector Pump.

Related Links

Water in fuel - test kit - Biopowered wiki home made calcium hydride test kit.

Sandy Brae Water Test Kit Instructions - Sandy Brae Labratories