Using the ECH MobilGC portable gas chromatograph and LPG sampling box for onsite measurements according to ASTM D2163

Application

ECH Elektrochemie Halle have developed a portable and robust gas chromatograph for use in the demanding petroleum industry, this article will look at one of the primary methods conformed to in the instrument, namely, ASTM D2163 which is the – “Standard Test Method for Determination of Hydrocarbons in Liquefied Petroleum (LP) Gases and Propane/Propene Mixtures by Gas Chromatography”.

Principle

The MobilGC portable gas chromatograph (GC) from ECH Elektrochemie Halle has a column oven and a microprocessor controlled modular system with temperature program. The instrument can be equipped with two injector systems, two detectors and two oven cassettes. The device has an integrated temperature regulation and a separate pneumatic module with pressure regulators for the carrier gas and additional detector gases. Control and evaluation of the digitized detectors are run by the integrated evaluation program, including storing of unprocessed data and report printing. The instrument can be used as GC for routine analysis, or automatic portable GC in connection with the integrated gas sample valve and automatic sample injection system. Storage and control of all methods is carried out in the software of MobilGC. The sample collection from the pressurised LPG cylinder is also possible with a sampling box.

Procedure

The standard MobilGC (device type 19”) with interface oven for column connection and pneumatic module with pressure regulator and manometer for detector channel and column is used. The interface oven for heating of injector and detector can be heated up to 150°C whilst the gas flow is in the following range: Carrier gas: 1.0 - 30 ml/min (helium) An automatically controlled injection sample valve with exchangeable 300 µl dosing loop is integrated in basic device. The sample is introduced by membrane pump through sample loop and injected automatically, 15 meter sample tube is included. GC separation oven cassette for determination of hydrocarbons with complete heating up to 250 °C and connection for interface oven. Oven cassette completed with micropacked column up to 4 m x 1.0 mm, graphite fit adaptor for connection to injector and detector basis. Detector TCD channel for micropacked columns and thermal conductivity detector installed in the valve oven. Bridged power supply with constant voltage. Digitalised electronics with V/F-convertor. Unprocessed data is automatically processed by the integration program. Pneumatic module with pressure regulators and manometer. Gas supply GC is connected to laboratory gas supply by 1/8” stainless steel tubes. Data acquisition system and integration software for Windows 7 or higher for automatic calculation of results contains the following features:

• Complete control of GC, raw data acquisition and temperature control of separation column and interface oven in real time
• Representation and evaluation of all relevant data
• Easy-to-handle, automatic or manual integration algorithms
• Compensation of interfering and distorting effects MobilGC - Application: Determination of hydrocarbons e. g. in LPG gas samples according to ASTM D 2163 4 / 5
• Automatic integration of peaks
• Numerous functions for documentation incl. report generator and export routines · Integrated plausibility tests
• Representation and evaluation of all relevant data
• Communications by RS 232

To learn more about the ECH MobilGC or ASTM D2163 please feel free to reach to one of our product experts or visit ECH - LPG

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