Improving the efficiency of CaO-based sorbent by SrCO3 for high-temperature sulfur removal during coal combustion

Abstract

With the goal of adding the appropriate amount of SrCO 3 to coal, the synergistic effects of SrCO 3 and desulfurization agents were studied by using a sulfur determination device and a carbon-sulfur spectrometer. Mineral constituents were investigated with an XRD diffraction analyzer. Results show that, at a given temperature, desulfurization efficiency increased in varying degrees based on the proportion of added SrCO 3 . An increasing amount of calcium sulphoaluminates also appeared in the ash residue. Meanwhile, SrCO 3 , sulfur capture capacity improved when the temperature reached 1200°C because of the large amount of generated calcium sulphoaluminates (3CaO·3Al 2 O 3 ·CaSO 4 ) and the controlled decomposition of CaSO 4 . At temperatures of 1200°C-1300°C, the ascending rate of the sulfur-fixing ratio decreased due to the sharp decomposition of CaSO 4 and the pyrolysis of a small amount of calcium sulphoaluminate. From 1300°C, the decomposition of increasing amounts of calcium sulphoaluminate gradually worsened the desulfurization. The diffraction peak of calcium sulphoaluminate was the strongest at 1300°C and the sulfur-fixing ratio was also the largest. Therefore, calcium sulphoaluminate reached the highest level at this temperature.

Influence of Compound Additives on Sulfur Fixing Performance of Sorbent Based on Steel Slag at High Temperatures

“…Auxiliary agents can increase the surface characteristics and pore structure of sulfurfixing agents, as well as delay and limit the decomposition of sulfur-fixing products [13]. They can also catalyze sulfur-fixing reactions and combustion.…”