Gas 2024 Issue

samples displayed some degree of liquid phase separation, as those chemical additives were partially or completely insoluble in the lean amine solvent. Nine samples exhibited solids precipita- tion, presumably due to chemical incompatibility between the formulation components and lean amine solvent. Forty-one chemical additive sam- ples were observed to have a significant amount of haze present after agitation due to effects including emulsification and solids dispersion. The observed effects of each chemical addi- tive sample heating (in comparison to unheated sample characteristics and 24-hour cooling) were not significant in most cases, as only sam - ple characteristics changed. Solids precipitation was observed in one additional chemical addi- tive sample after heating. Sample opacity was largely unchanged.However, some chemical additive samples slightly clarified or became a lit - tle hazier. Some samples were observed to have slightly changed foaming tendency after heat- ing, but most chemical additive samples were

Figure 2 Image analysis of lean amine solvents with various chemical additive samples in terms of compatibility and colour change at: left: room temperature and right: at 60ºC for five hours. Red squares show the samples that changed colour upon heating. Samples 1, 11, 19, 21, 38, 40, and 51 showed a marked colour change upon heating

after heating at 60°C for five hours. From exposure to the various process additives at room temperature, the colour changes in the amine solvent were clearly visible. The samples with an inner ring contour, grey colour, are indicative of no changes to the transparency of the amine upon addition of the process additive. Some samples still show the inner ring, but there is a slight colour change. This indicates that the sample has changed colour but is still transparent. The other samples where the inner ring is not visible indicate that the samples changed in colour and became opaque (hazy) or presented a separate phase. About 50% of the samples turned the lean amine solvent opaque (30 chemical additives), and five additives changed the solvent in colour but did not cause the mixture to become opaque. In addition, seven samples indicated by the red squares changed colour upon heat exposure. Samples 1, 11, 19, 21, 38, 40, and 51 showed a marked colour change difference after heating. These evaluations are only visual observations and were used in combination with the other observations, such as solids formation and foam stability. Foam-inducing chemical additives A total of 42 chemical additives produced lean amine sol- vent foaming, as shown in Table 4. * The products marked in red generated severe foaming. Figure 4 shows the seven

unchanged. The most significant change in characteristics was liquid phase separation; six chemical additive samples were observed to have dissolved their discontinuous phase after heating and cooling time. Additive analysis The complete analysis shows that about 75% of the chem- ical additives tested resulted in some form of observed incompatibility. Some chemical additives displayed a greater degree of incompatibility compared to others, and continued use of those products with significant incompat - ibility should be replaced. At least 12 chemical additives presented moderate to severe foaming tendency of the lean amine solvent (see Tables 2 and 3) * and should be recon- sidered and re-evaluated for use or potentially replaced. Additionally, eight chemical additive samples showed solids precipitation when contacted with lean amine sol- vent, and 23 chemical additive samples generated liquid phase separation (see Tables 2 and 3). * All these products should be reconsidered for use or potentially replaced. Any samples with severe haziness or complete opacity should be reconsidered for use or also potentially replaced. Compatibility image analysis To gain an understating from a visual perspective of each chemical additive and their effect to heat exposure, chem- ical additive samples 1-61 containing the lean amine sol- vent and the chemical additive samples were scanned from the bottom of the glass vial and analysed by their visual properties (see Figure 2 ). The vial array codification related to the various additives is indicated in Figure 3 . Samples highlighted in red in Figure 2 show a marked colour change upon heating. The section and colouration of the various additives when contacted with the lean amine solvent are shown in Figure 2. The section on the left shows the mixtures at room tem- perature, and the image on the right shows the mixtures

Empty Control

54 53 52 51 50 49 48 47 46

45 44 43 42 41 40 39 38 37

36 35 34 33 32 31 30 29 28

27 26 25 24 23 22 21 20 19

18 17 16 15 14 13 12 11 10

9 8 7 6 5 4 3 2 1

61 60 59 58 57 56 55

Figure 3 Position codification of chemical additives contacted with lean amine solvent

Gas 2024