Process Measurement via Gas Chromatography in the Natural Gas and Biogas Industry
Gas trading is based on energy billing.
The basic challenge for gas measurement is to determine the energy for fiscal billing. It is therefore of great economic and technical importance to have a knowledge of the gas properties.
The varying calorific value of natural gas is the
key figure to know.
The energy flow is the product of calorific value and volume flow at standard conditions. For this calculation, volume at flowing conditions must be converted to volume at standard conditions by pressure and temperature state conversion and regarding the non-ideal gas property of the natural gas.
Modern process GCs are based on microsystems technology with micro-electro-mechanical systems (MEMS). The key functional blocks of a GC, injector, column, heating, detector are highly miniaturized and integrated, resulting in various advantages.
Natural gas :For standard billing requirements
it is sufficient to quantify the main components methane, ethane, propane, i-butane, nbutane,
neo-pentane (not always required), i-pentane, n-pentane. Furthermore all significant
hydrocarbons with higher order then n-pentane must be quantified.
Biogas : The composition of raw biogas varies depending on the feedstock involved with the main components methane and CO2, minor components are N2, H2 O2, H2O, H2S and further trace components. |