Role of porosity loss in limiting SO₂ capture by calcium based sorbents

Abstract

The extent of high temperature (900-1,3OO"C), short time ( t l s) SO, capture was found to be limited by temperature-dependent losses in the porosity of calcium based sorbents. At 970°C these porosity losses were caused by C0,-activated sintering. Sulfation of the sorbents either prevented or reduced the extent of porosity losses. Differences in SO2 capture between hydroxides from different commercial sources, and significantly lower levels of capture by calcium carbonates compared to hydroxides were attributed to differences in particle size and the degree of porosity loss. SummaryThe use of a CO-fired reactor allowed calcines (CaO) of CaCO, and Ca(OH),, to be sampled without significantly alter- Vol. 35, No. 6AIChE Journal

Pore‐structure optimization of calcium carbonate for enhanced sulfation

“…Another possible factor is the effect of sintering on pore volume is diminished in the presence of SO,. Newton et al (1989) performed calcination and sulfation experiments in the presence of CO, and observed a reduction in sintering effect during sulfation. They concluded that during sulfation, the influence of CO, in accelerating the rate of sintering is inhibited due to the product layer surrounding the CaO grains.…”

Feasibility Study of Using Carbide Slag as In-Bed Desulfurizer in Circulating Fluidized Bed Boiler

“…The specific surface area reflects the size of the gas-solid reaction interface, whereas the specific pore volume reflects the size of the diffusion space for the gas molecule. Since CaSO 4 has a larger molar volume than CaCO 3 and CaO (52.2, 36.9, and 16.8 cm 3 mol −1 , respectively) [20], the produced CaSO 4 blocks the pores, leaving a large amount of unreacted CaO inside the particles, and reducing the utilization of the desulfurizer [21]. For the CaO with large pore size, the blockage can be delayed and the effective reaction time will be prolonged.…”

Impact of porosity on calcination and sulfation of calcium sorbents

“…2 show, a positive effect on the RI index is from open porosity: the higher the open porosity, the higher the RI index determined by means of the FW method. Open sorbent pores facilitate the process of initial sorbent calcination, followed by sulfation through mechanical processing of the sorbents before use [5][6]. Degree of the use of sorbent for desulphurization depends on the chemical composition of sorbent and, as results from the data contained in Tabs.…”