For energy efficiency and environmental protection reasons, the iron and steel industry is increasingly using internally-produced process gases as combustion gas for thermal processes within the plant (e.g., for hot rolling) instead of flaring them. The unavoidable fluctuations of energy content in process gases are compensated for in mixing stations where natural gas is added in a precise amount determined by measurement.

Both calorimeters and gas analyzers are used for determining the controlled variable for the mixing station. UNION Instruments uses the modular CWD2005 / 2005 PLUS (calorimeter) and INCA (multi-gasanalyzers) devices for this and even combines the two devices into a single system in highly-optimized cases. To take into account the effect of line dimensions, which is relevant to gas mixing operations, UNION Instruments has developed an adaptable measured value computer model based on time-delay elements.

By reliably conditioning the process gases produced in each case based on a defined composition using mixing stations, process gases can also be used as combustion gases for exacting thermal processes, for example, with explicitly defined excess air. This has major financial benefits while simultaneously assuring quality for thermally treated workpieces or products.

In iron and steel production energy rich process gases are generated. At the same location, gas is also needed as an energy source for thermal processes. Before being used for that, the gases must be monitored for a minimum combustion value and the Wobbe index. For adjustment of the combustion value and the Wobbe index, natural gas or liquefied petroleum gas is added, as necessary.

UNION Instruments offers an optimally equipped version of its modular INCA gas analyzer as a solution for this. This determines the content of methane, higher hydrocarbons, and oxygen. The measured values serve as a control variable for any needed natural gas addition. The special NDIR technology of INCA compensates for overlaps in the spectrum and thus assures an especially high measuring accuracy.

The composition of the combustion gas influences the start characteristics, efficiency, and knock resistance of gas-powered engines. The use of INCA assures optimal operating conditions for the engine and prevents problems that can lead to destruction of the engine and significant subsequent damage.