Effect of the Pore-Size Distribution of Lime on the Reactivity for the Removal of SO₂ in the Presence of High-Concentration CO₂ at High Temperature

Abstract

To develop a SO 2 sorbent that is highly reactive in the presence of high concentrations of CO 2 at high temperature, the effect of the pore-size distribution on the reactivity was investigated at 800°C using a natural limestone, natural lime, modified macroporous lime, and limestone. The modified lime samples were prepared from a kind of natural lime by water-acetic acid swelling and water swelling methods. The modified limestone was prepared from the modified lime by carbonation. Pores smaller than ca. 200 nm in the modified lime and natural lime virtually disappeared, and pores larger than ca. 200 nm also considerably decreased in pore size after carbonization. The reactivity of the modified limestone depended on the degree of development of pores larger than 200 nm, because the macropores provided a diffusion route for SO 2 in the sorbent during sulfation.

Calcium-based sorbents behaviour during sulphation at oxy-fuel fluidised bed combustion conditions

“…The second one was slower and it can be controlled by diffusion through the CaSO 4 product layer. It must be remarked that, for the typical residence times of solids in FBC, the residual activity of the sorbent to the diffusion in the product layer was very important [15].…”

“…[9][10][11][12][13][14][15][16][17][18] However, few works analyse the sulphation at oxy-fuel combustion conditions [19][20][21][22] and the major are related to non-calcining conditions. These studies found that the most important factors affecting to sulphur retention with Ca-based sorbents were temperature, CO 2 concentration, particle size and SO 2 concentration.…”

Chemical Looping Particles

“…Figure 2.44 shows that the wt.% capacity of the LC -based sorbent for CO 2 capture reduces from 58% in the fi rst cycle to 20% at the end of the 50th cycle caused by sintering or grain growth in the LC precursor in the course of cyclic reactions, rendering the structure susceptible to pore pluggage and pore mouth closure. 104,112,113 In contrast, it is shown in Figure 2.45 that the conversion of PCC -CaO during 100 cycles is distinctly higher than that of the LC -based sorbent. The capacity shown in Figure 2.45 is ∼ 68 wt.% in the fi rst cycle, which decreases to 40 wt.% in the 50th and slightly lower than 36 wt.% by the 100th cycle over ∼ 6,000 minutes on stream.…”

Sulfation, pore, and fractal properties of hydrated spent calcium magnesium acetate from calcium‐based looping

“…Acid swelling is an experimental method for solving the incomplete conversion problem in the CaO reaction with SO 2 . It was proposed by Wu et al . The CaO sorbent was treated with acetic acid.…”