Effect of NaOH Addition on the Reactivities of Iron Blast Furnace Slag/Hydrated Lime Sorbents for Low-Temperature Flue Gas Desulfurization

Abstract

NaOH was added to iron blast furnace slag (BFS)/hydrated lime (HL) slurries to prepare the sorbents for semidry and dry flue gas desulfurization (FGD) processes. For sorbents prepared without NaOH, both the Ca utilization and the SO 2 capture increased with increasing slurrying temperature and varied with the BFS/HL weight ratio. With NaOH addition, the sorbents contained much less high surface area products of pozzolanic reaction. Their reactivities were insensitive to the slurrying temperature and greatly enhanced when the NaOH/(BFS + HL) ratio was about 10/100. NaOH is deliquescent, and its presence increases the amount of water collected by a sorbent, which is required for the sulfation of a sorbent at low temperatures. The use of NaOH addition at or below the optimal ratio can raise the sorbent reactivity and reduce the cost of sorbent for a semidry or dry FGD process.

Integrated carbon dioxide/sludge gasification using waste heat from hot slags: Syngas production and sulfur dioxide fixation

“…3(b) and (c), the maximum SO 2 concentration was pronouncedly reduced from 81 ppm, 164 ppm to 70 ppm, 114 ppm, by the BFS and to 57 ppm, 93 ppm by the SS gasifying at 800°C and 900°C, respectively; thus, the SS showed a stronger sulfur fixation because of the relatively higher content of CaO. In fact, the utilization of SS as desulfurizer in wet process has been explored in a previous study (Liu and Shih, 2004), which showed a predominant performance to reduce the SO 2 content in the flue gas. Generally 3CaOÁSiO 2 and 2CaOÁSiO 2 are the main mineral phases in the SS, as demonstrated by XRD results in Supplemental Fig.…”

Evaluation of various additives on the preparation of rice husk ash (RHA)/CaO-based sorbent for flue gas desulfurization (FGD) at low temperature

“…The relative humidity is consecutively connected to moisture content of the solids. In addition, some additives have been employed to alter the moisture content on the prepared sorbent surface in equilibrium with a gas phase of a given relative humidity [18][19][20][21][22][23]. Thus, the use of additive would then be expected to improve the sorbent SSC in desulfurization processes in the way of altering the sorbent particle's physical/chemical properties.…”

The effect of hydrogen peroxide solution on SO2 removal in the semidry flue gas desulfurization process

“…Thus, these processes are very attractive for the desulfurization retrofits in the old units. However, compared with wet FGD processes, SO 2 removal efficiency and sorbent utilization in the semidry FGD processes are relatively low [4,5]. Moreover, a great variety of analytical methods have revealed that the products of the semidry FGD processes primarily contain Ca(OH) 2 and CaSO 3 ·1/2H 2 O [6][7][8].…”