Written by Rickdatech

API Gravity of Diesel

One of the field tests for Diesel Fuel is to measure it’s specific gravity.  ASTM D287, Standard Test Method for API Gravity of Crude Petroleum and Petroleum Products (Hydrometer Method) is the official ASTM test procedure used by the petroleum industry. This test actually measures density using a hydrometer calibrated to the API Gravity scale. API Gravity is inversely proportional to specific gravity. As API gravity goes up, specific gravity goes down. The formula that relates API to SG is:

API = (141.5 / SG) - 131.5 (1)

The petroleum industry uses API Gravity as an indication of energy content of the fuel. As API Gravity increases energy content decreases. Since specific gravity is the inverse of API Gravity, a higher specific gravity means a higher energy content fuel. As Specific Gravity increases, power output and mileage both increase. The API limits for D2 Diesel are 30 to 45. That translates to specific gravities of 0.876 to 0.802.

3M offers a test strip for measuring FFA% of oil. The strips cost about 50 cents a strip and will quickly tell us roughly how good or bad your oil is. It's a great idea for when your scouting for sources and want to test the oil on site.

They have two different strips. The "Normal Range" strips have four steps from 7% FFA. That's NaOH titrations ranging from 2.6 to 9.1. The "Low Range" strips have four steps from 2.5% FFA. That's like NaOH titrations ranging from 1.3 to 3.2.

3M recommends using them when the oil is at operating temperature,  but hobbyists  have tested it on room temperature oil and found the strips are just as accurate at room temperature. They do however take several minutes instead of several seconds to completely change colors.

One other note is they only have a one year shelf life, so don't buy more than you can use in a year. Someone suggested keeping them in the frig or freezer, but I don't know if that is necessary or not.

Related Links:

3M Oil Quality Test Strips - amazon.com

Testing for FFA - Frybrid forum thread 

3M Brochure .

Written by Rickdatech

If you use Home Heating Oil (HHO) to heat your home, Making Biodiesel at Home can lower your heating bill. Most people can run a B20 without any modifications. A few people have reported issues with higher blends. The problems include inconsistent starting, clogged filters and dripping nozzles.

Biodiesel is an excellent solvent. It will dissolve the crud in your HHO tank and dump it in your fuel filter, clogging it. Most filters have a bypass built into them. When the filter clogs, the bypass opens, and dirty fuel bypasses the filter, clogging up nozzles and lines. Trash making it's way into the nozzle is also the cause for dripping nozzles. The cheap fix is to watch and replace the filter when it clogs. Filters are only a few dollars.  If your HHO tank is old, it will probably be best to replace it or have it cleaned before using biodiesel.

Written by Brad Wilder

The 80/20 method as it is called is simply the practice of breaking the biodiesel reaction process into two, and sometimes three (77/22/1), parts. Specifically, this is done to reduce soap counts, counteract higher water content, and increase yields from high water oils. Testing during each stage of the process can also be used to help troubleshoot recipe quantities and bad batches.

Written by Rickdatech

Test your biodiesel knowledge with this easy test.

 
Source US Energy Information Administration