ABSTRACT
The combustion calorimeter directly measures the thermal energy generated from the combustion of a known volume of gas. In contrast, the gas chromatographs (GCs) determine the heating value indirectly by measuring the composition of the gas and calculating the heating value by using the heat of combustion of each gas component. Several process GCs were tested to verify whether this instrument is an accurate alternative to the calorimeter for measuring the heating value of natural gas. The old laboratory GC required an operator to inject samples and to interpret the results. The use of microprocessors in process GCs allows the GCs to become an integral part of a gas company's data acquisition system. The laboratory GC was calibrated with a calibration gas which was blended gravimetrically. The GCs and calorimeters were individually calibrated by a separate independently-supplied calibration gas. The process GCs were calibrated against the laboratory GC using another independently-supplied calibration gas.
