Impact of dissolved and undissolved organics on foaming of industrial amine

The effect of soluble and insoluble organics i.e. liquid paraffin, carboxylic acids, and BTEX on foaming behavior of industrial fresh and lean amine solution was investigated. Different fresh and lean amine samples were saturated with different organics through mixing the amine solution with the organics in thermodynamic cell until equilibrium. Saturated amine samples were extracted from the equilibrium cell and foaming study was carried out for each saturated amine solution. The effect of insoluble organics on the amine foaming behavior was tested through adding excess organics to the saturated amine. The results of this study showed that dissolved organics increased the foam volume in fresh 50 wt% MDEA solution. However, adding excess organics, above the solubility limit, into the fresh amine decreased the foam volume. Interestingly, saturated industrial lean amine with normal liquid paraffin (C6-C7) decreased the foam volume of the industrial lean amine. Moreover, the foaming tendency decreased significantly when the concentration of normal liquid paraffin exceeded the solubility limit in the tested lean amine solution. It is noted that cyclohexane has more influence in amine foaming than n-hexane. Saturated industrial lean amine solution with carboxylic acids dramatically increased the foam volume. Adding excess carboxylic acids above the solubility limit decreased the foam volume of the saturated amine, however, it remains higher than the foam volume of the original lean amine. Soluble toluene and xylene increased the foam volume from 120 ml to 647 ml and 471 ml, respectively. Adding excess BTEX over the solubility limit to the saturated lean amine reduced the foaming tendency of the saturated amine. However, as observed with the carboxylic acids the foam volume with excess BTEX still showing higher volume over the original lean amine. The findings of this study highlight the importance of controlling the concentration of BTEX compound entering to the amine unit over the liquid hydrocarbons as a common foaming mitigation practice. Also, the findings of this study highlight the importance of monitoring the generation of carboxylic acids due to amine degradation and control its concentrations for smoother operation.