Course: BFM 202 Biodiesel Production

Lecture

Biodiesel Lubricity and Effect of Biodiesel on Lubricants
Credits
BFM 202 Biodiesel Production Unit 1 Reading has been adapted from "ENGY 131 Unit 1 Commentary: What is biodiesel?" by Southeastern Illinois College.

ENGY 131 Biodiesel Production course content by Southeastern Illinois College is licensed under a Creative Commons Attribution 3.0 Unported License. Except where indicated otherwise.

Lubricity of Neat Biodiesel and Petrodiesel

In diesel engines, fuel provides the lubrication for the injectors and fuel pumps. Biodiesel increases lubricity. B100 or neat biodiesel has excellent lubricity and can increase lubricity in petroleum-based diesel fuel, including aviation fuel.

However, ultralow sulfur diesel, ULSD, required by European and U.S. environmental agencies doesn't sufficiently lubricate the diesel engine since the hydrodesulphurization process removes the lubricity components of oxygen and nitrogen from the fuel.

Due to its high boiling point, biodiesel is less likely to evaporate in the crankcase of an engine. Petrodiesel is prone to this phenomenon which results in oil dilution and excessive engine wear. Fresh biodiesel can decrease this wear by reducing metal concentrations in the lube oil, but aged biodiesel tends to increase that wear due to its partial oxidation. At one time, OEM's recommended more frequent oil changes but that's no longer the case.

Two specifications govern lubricity testing, ASTM D6078 is the scuffing load ball-on-cylinder lubricity evaluator and ASTM D6079 uses a high-frequency reciprocating rig lubricity tester.