Measuring the calorific value of mixed gaseous fuels can be difficult. These complex mixtures of combustible and non-combustible gases and vapors can vary in concentration or composition over time due to changing conditions. Perhaps it is the rate of change or a wide range of water vapor at different process temperatures. Maybe the combustibles vary widely in composition under different process conditions. It's also possible that the heating value itself varies over a wide range, very lean at some times and very rich at others. Either way these conditions present measuring challenges.
Here are 6 things to consider when designing a system for continuous monitoring of the calorific value of mixed gaseous fuels:
- Heating prevents errors from condensation of water vapor. The sample stays intact during measurement.
- Heating allows combustible gases with low vapor pressure (high boiling points) to be measured without losses in the sampling system. False low readings are avoided.
- The aspirated system does not increase pressure above the process conditions, preventing condensation of water vapor or combustible gas that would otherwise condense. The sample is not affected.
- Combustion calorimeter has good response factors, especially useful for unknown mixtures, practically “anything that burns.”
- The use of hydrogen fuel stabilizes the flame and widens the measurement range, including zero. The flame is always ready to measure.
- Its speed provides a continuous measurement that is useful when process conditions can change quickly. Speed can be as important as accuracy. Often, speed is crucial.