Biofuels
From LEAP
| Biofuels |
| Application Type | |
| Sample Prep and Inject | |
| Application ID | |
| Biodiesel ASTM 6584 | |
| Description | |
| Determination of Free and Total Glycerin in B-100 Biodiesel Methyl Esters by Gas Chromatography |
Overview
Glycerin content can indicate the quality of biodiesel. Glycerin can be in the form of free glycerin or bound glycerin in the form of glycerides. Total glycerin is the sum of these. A high content of free and total glycerin can lead to buildup in fuel tanks, clogged fuel systems, injector fouling and valve deposits. Unrelated glycerides and free glycerin make the product behave more like soap rather than fuel.
ASTM Method D6571 specifications serve as the benchmark which identifies the standards that pure biodiesel (B100) must meet before being used as a fuel or blended with petrodiesel. The US National Biodiesel Board has adopted the ASTM biodiesel specification and analytical methodology. ASTM recommends test method D6584 for the analysis of glycerin in biodiesel fuel by gas chromatography. The limit for the total glycerin is 0.240% by mass.
Gas chromatography can also serve as a tool for process troubleshooting during biodiesel production to ensure trouble-free operation of the fuel in diesel engines. Monitoring the level of free glycerin and any unrelated mono-, di-, and triglycerides will indicate the efficiency and progress of the chemical reaction during the process of making biodiesel.
LEAP's Approach
System shown above with Agilent 7890 and Twin PAL. The Lower PAL is the Prep PAL and runs on Cycle Composer Software. All of the sample prep is performed with this PAL. There is a 100ul syringe for the solvent transfers. There are (7) 2mL solvent locations. There is a DISPTool that is hooked up to a 5 mL dilutor syringe for the 8 mL Heptane addition. There is a fast wash station that Wash1 is filled with Toluene and Wash 2 is filled with Heptane. There is an agitator that is set at 35 deg C and 500RPM to do the mixing.
The Upper PAL is the Inject PAL and runs under ChemStation Software control. This requires Agilent CTC Control Software supplied by Agilent. It is using a 5 ul syringe with a tapered needle to do 1 ul on column injections into the rear injection port. There is a fast wash station that Wash1 is filled with Toluene and Wash 2 is filled with Heptane.
The expected Sample Prep Time is approximately 26 minutes The expected GC Runtime is approximately 31.81 minutes The expected GC Cool down time is approximately 7 minutes
