OCR Text |
Show of varying purity, on a per unit sorbent weight bais. The individual values of the relative sorbent efficiencies shown in Figure 4 are arithmetic averages of six values of E. calculated from humidifier and I system 502 removals in three runs at different test conditions for all the sorbents, except for Limes H and I. For Limes H and I, the averages were calculated from four values of E. because only two runs I were made with these sorbents. Figure 4 shows that hydrated calcitic Lime A was the best performer among the 12 test sorbents. For the other 11 sorbents, values of the relative utilization efficiency (E.) were significantly lower than the 100 I value for Lime A. Four of the test sorbents (F, H, O-A, 0-8) had values between 65 and 77, giving sorbent utilizations on average 23 to 35% lower than with hydrated calcitic Lime A. Seven other sorbents (8, C, 0, E, G, I, J) showed intermediate Coolside performance, giving sorbent utilizations 10 to 20% lower than hydrated calcitic Lime A (i.e., average E. values of 80 to 89%). I The sorbent evaluation results indicated that hydrated calcitic limes are superior to pressure hydrated dolomitic limes for Coolside desulfurization. Table 1 shows that under conditions chosen for maximum 502 removal (i.e., (Ca+Mg)/S = 2 and Na/(Ca+Mg) = 0.2), the two pressure hydrated dolomitic limes tested (O-A and D-8) gave lower 502 removals than any of the hydrated calcitic limes. The hydrated calcitic and dolomitic limes were tested at roughly the same values of the (Ca+Mg) IS mol ratio. Figure 4 shows that based on the relative sorbent efficiency, the hydrated dolomitic limes were among the four least effective sorbents. This indicates that the dolomitic hydrated limes are inferior on a per weight basis, even though they provide more mols of alkali per unit sorbent weight. SORBENT VARIABLE EFFECTS For the 10 di fferent hydrated calcitic I imes tested, Coolside 502 removals without NaOH additive injection increased moderately with 5 |