Correlation of HF acid corrosion with hydrogen flux readings

HF is used to catalyse the formation of branched C8 olefins from smaller olefins. An alternative catalyst – sulfuric acid – can also cause corrosion issues, but provides a much weaker flux signal.

The chemistry of HF corrosion of steel is remarkably rich, as summarised in the schema below:

Despite this, HF corrosion of steel tends to be widespread, and provides a very robust and extensive flux mapping has confirmed that HF generates a very robust signal; it can even be used to identify a significant presence of HF in a process stream.

There is probably some temperature dependency for corrosion-flux correlation, not considered in the chart below, which should be used only to provide an approximate indication of conversion rate provided by a hydrogen flux. Note the flux thickness is calculated from the flux in pL/cm2/s multiplied by the thickness of the steel, in cm.