Utilise Process Gases Instead of Flaring Them

Today, even though they have less energy content than natural gas, process gases produced in many process-related operations and especially in the steel industry are being collected in gasometers and used as combustion gas in place of natural gas in thermal processes. However, the fluctuating composition of the process gas, especially the CO content and the related fluctuating energy content, calls for special measures.

The energy content of the gas composition is stabilised by controlled addition of natural gas. One measuring system that is specially configured for this task is the CWD2005 direct calorimeter from UNION Instruments (Germany) with additional integrated gas analysis and measured value processing. The system determines the Wobbe index and gas density values as well as the concentrations of CH4 and C2+. The heating value and air requirement are also calculated from this. Altogether the information from the calorimetry and gas analysis is a basis for sufficiently accurate control of the gas addition.

It is important that the measuring device reacts fast enough to ensure the control process, which requires special measures due to the size of the plant and the mixing of gases in the pipe system. UNION Instruments has developed a computational model based on delay elements that can be adapted to different plant dimensions by assigning parameters.