A hot potassium carbonate (K2CO3) solution is used in the Benfield process as a scrubbing liquid. The gas to be cleaned is passed under high pressure in a coun-terflow through the K2CO3 solution in the absorber. The scrubbing solution K2CO3 is enriched with CO2 and reacts partially to potassium bicarbonate KHCO3. The purified gas leaves the absorber at the upper end. The temperature range in the absorption process is between 100 °C and 110 °C.
The desorption is carried out by steam and under pressure loss, whereby the captured CO2 is emitted into the scrubbing liquid. The regenerated K2CO3 is then fed back to the absorption cycle. The LiquiSonic® 40 analyzer allows the optimal response to concentration fluctuations in the scrubbing liquid. Too high KHCO3 concentration results in foam formation and lesser CO2 absorption performance. At too low K2CO3 concentration, sufficient absorption is not ensured.