Control of Residue Content in LPG by GC Methods ASTM D7756-13 and PrEN 16423

To control the residue content in LPG there are several methods available. Latest methods are ASTM D7756-13 and PrEN 16423: fast, safe and accurate methods to determine oily residues in LPG by gas chromatography with the Liquefied Gas Injector (LGI). These GC methods are the alternatives to the conventional methods ASTM D2158, EN 15470 & EN 15471 and ISO 13757, which are not direct injection GC based and require evaporation of large volumes of the liquid sample.

The LGI incorporates a large volume high pressure liquid sampling technique developed by Da Vinci Laboratory Solutions (DVLS). The innovative design of the LGI provides laboratories with a safe, reliable and efficient method to determine oily residues and contaminants in C3 and C4 streams as a result of:

• High pressure liquid sampling technique - A high pressure injection valve connected to an injection needle ensures a direct on-column LPG injection.
• No need for sample evaporation - 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.
• Safe and easy connection of sample container – The Pressure Station allows to install the sample container on the front side of the system and vents the waste sample to a central waste system.
• No need for sample preparation - 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.
• Reduced bench space - The controller box is installed on top of the GC and drives the injection cycling.

For the petrochemical industry new applications are also available for the analysis of:

• Elemental Sulfur in LPG
• Desulfurization additives in LPG such as DIPA, MEA & DEA
• Inhibitors, additives and Dimers in Butadiene: ρTBC, VCH and NMP
• Natural Gas Condensate

Download the application notes from the Petrochemical Industry section for more information or visit the chromatography section.