03. Sep 2021
Gas quality monitoring in LNG ships can significantly increase efficiency, reduce emissions and improve operational safety.
Gas-powered engines show clear advantages in terms of CO₂ and pollutant emissions over engines that run on conventional fuels such as diesel or heavy fuel oil. Since the composition, and thus the quality of natural gas can vary considerably depending on its origin, two key aspects must be considered when operating a gas engine: safety and efficiency.
The safety aspect refers to the dangerous occurrence of engine knocking, where uncontrolled combustion occurs in the cylinder, destroying a large engine within a short time. gasQS™ technology enables "pre-process sensing" by testing the supplied gas for its anti-knock properties. This means that the dangerous condition can be dealt with before it occurs. The parameter usually used for this is the methane number, which must have a certain minimum value to ensure the safe operation of a gas engine.
Once in safe operating condition, changes in gas quality can have a significant impact on the efficiency of a gas engine. However, this is not noticeable in normal operation unless these changes are detected by dedicated sensors. gasQS™ technology makes it possible to determine not only general variables, such as the calorific value or the Wobbe Index, but also engine-specific, relevant process variables, such as the optimum ignition angle, so that the engine can be perfectly adjusted to the gas quality.
The diagram illustrates the increase in efficiency obtained by readjusting the ignition angle using the example of hydrogen content in natural gas.