Dual analysis of Oily Residues and Hydrocarbons in LPG

The DVLS Liquefied Gas Injector is a dedicated GC solution for the high pressure liquid sampling and analysis of C3 - C4 streams such as LPG. The Liquefied Gas Injector is standardised as ASTM D7756 and EN 16423 to determine the residue content in LPG through direct on-column injection. Adding a liquid sampling valve and an external GC oven extends the residues analysis to determine the hydrocarbon composition at the same time from the same sample cylinder.

Oily Residues in LPG ASTM D7756
Fuel specifications for oily residue in LPG list ASTM Method D2158 or EN Method 15470-1. Both quantifications are not very accurate and offer a safety risk due to the required evaporation of flammable LPG samples.
To provide the industry with a safe and accurate alternative Da Vinci Laboratory Solutions (DVLS) developed the Liquefied Gas Injector (LGI). The direct injection approach of the LGI includes the proven fuel direct injection technique used by the automotive industry to inject fuel into the automotive engine combustion chamber.

The LGI is configured on top of the GC and consists of a high pressure injection valve connected to an injection needle. The LGI pressure station and the GC enable a constant pressure of the liquid sample and allow to inject a representative and repeatable amount of the sample.

The chromatographic analysis after the sample introduction is based on boiling point separation of the oily residues and contaminants.

Hydrocarbon Composition of LPG ASTM D2163
The LGI application dedicated to the hydrocarbon compositional analysis of LPG complies with ASTM D 2163 and ISO 7941. For a dual analysis of the residue content and the hydrocarbon composition the LGI application was extended with a liquid sampling valve, a Split/Splitless inlet, an FID detector, an analytical column and an external oven.

Download the application note for more information on the dual analysis of ASTM D7756/EN 16423 and ASTM D 2163/ISO 7941 within 30 minutes.

The DVLS Liquefied Gas Injector offers the petroleum industry a proven GC standard for the sampling and analysis of C3-C4 streams:

• Innovative sampling technique - A high pressure injection valve connected to an injection needle ensures a direct on-column LPG injection.
• High safety - The direct injection approach of the LGI eliminates the need for sample evaporation of the LPG.
• Representative sample injection – The Pressure Station allows to inject a representative sample of the pressurised gas as a liquid.
• Wide application range:         
  • Oily residues and light contaminants in LPG (ASTM D7756, EN 16423)
  • Hydrocarbon composition of LPG (ASTM D 2163, ISO 7941)
  • Sulfur compounds in liquefied petroleum gases
  • Desulfurization additives in LPG: DIPA, MEA & DEA
  • Inhibitors, additives and Dimers in Butadiene: ACN, ρTBC, Butadiene Dimer
  • N₂, CO₂, H₂S and Hydrocarbons in Unstabilised Gas Condensate.
• Fast analysis time of less than 30 minutes.