When cleaning gas streams, the focus is on avoiding under- or overdosing of the washing liquid to prevent insufficient gas cleaning on one hand and excessive material use and associated costs on the other. Continuous measurement directly in the process ensures optimal concentration management.
Sound velocity measurement with the LiquiSonic® Controller 40
Application
In the Benfield process, hot potassium carbonate solution (K2CO3) is used as an absorbent. The gas to be cleaned is passed countercurrently through the K at high pressure (e.g., 2 MPa)2CO3 -Solution is passed into the absorber. This enriches with CO2 and partially reacts to potassium hydrogen carbonate (KHCO3). At the top end of the absorber, the purified gas exits. The temperature during the absorption process is usually between 100 °C and 110 °C.
During desorption using steam and pressure loss, the absorbed CO2 is released back into the washing liquid. The regenerated K2CO3 is then fed back into the absorption cycle.
The LiquiSonic® Controller 40 enables response to concentration fluctuations of the washing liquid. With too high KHCO3-Concentration, foaming and reduction of CO2 -Absorption behavior occurs. With too little K2CO3 sufficient absorption is not guaranteed.
Installation
The LiquiSonic® Immersion sensors können leicht direkt in die Rohrleitung installiert werden. Eine übliche Installationstelle befindet sich in den Rohrleitungen (DN80) vom Absorber zum Desorber bzw. in dessen Rückführung. Die robuste Sensorkonstruktion und die Wahl von Sonderwerkstoffen, wie HC2000, sichern lange Prozessstandzeiten des Systems.
The LiquiSonic® Controller 40 is connected with the LiquiSonic® Sensor as well as the measuring unit for the second physical quantity. The controller displays the concentration of the K2CO3 - washing liquid as well as the KHCO3 - salt in the main menu.
Typical measuring range:
Concentration range of KHCO3: 0 to 25 m%
Concentration range of K2CO3: 0 to 25 m%
Temperature range: 80 to 110 °C
Customer benefits
LiquiSonic®ensures precise concentration measurement in a 3-component liquid with permanent data recording. This enables automatic regulation of the K2CO3 - solution in the area of maximum absorption or maximum efficiency of the gas scrubber.
LiquiSonic®reduces time-consuming laboratory measurements:
- Time required: 1 h per day
By avoiding over- and under-dosing, material costs are saved in the absorber (K2CO3) and desorber (steam).
In many industrial plants, contaminated gas occurs, such as in ammonia synthesis or in an ethylene oxide plant. For quality reasons, the CO2-enriched gas must be purified. A well-known process in the chemical industry is the Benfield synthesis gas scrubber, where the acidic components (e.g., CO2) in the gas stream are absorbed using a washing solution.
