SO₂ removal characteristics using waste CaO from calcium looping CO₂ capture process

Abstract

Calcium looping (CaL) has been identified to be a valuable candidate for CO2 capture and has entered a stage of large‐scale experiment and application. However, the serious loss‐in‐capacity problem will result in the production of a large amount of waste CaO, which not only increases the economic cost of the capture process, also generates a huge risk of secondary pollution. In this work, the waste CaO from CaL was first proposed to be used for SO2 removal by wet desulfurization and the SO2 sorption characteristics were comprehensively studied. Through experimental test and analysis, it is found that CaL‐spent CaO derived from dolomite can achieve higher efficiency than that from the limestone in SO2 removal. The effect of CaL cycle on the SO2 removal performance is observed to be small when the cycle number is under 40. Beyond that, the SO2 removal capacity decreases quickly, which is thought to be due to the variation in slaking rate determined by the compromise between the surface area and pore size distribution of the material. Furthermore, sulfation performance of waste CaO is found to be superior with a particle size smaller than 0.4 mm. This work proves the feasibility of the utilization of CaL‐spent CaO in wet SO2 removal, and could be beneficial for understanding the SO2 sorption characteristics of CaL‐spent materials. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd.

Pore and fractal descriptions of a modified CaO‐based sorbent for sequence SO2/CO2 capture behavior

“…Therefore, sequence SO 2 /CO 2 capture technology with more environmental benefits has been proposed and will be more attractive as the control on discarded spent adsorbents and SO 2 emission is strengthened and the operating cost decreases. The sequence SO 2 /CO 2 capture performance of normal CaO‐based adsorbents such as natural limestone, lime mud, and calcium magnesium acetate (CMA) have been analyzed in the published literatures . Considering the relatively high cost of a modified CaO‐based adsorbent such as CaO/Ca 12 Al 14 O 33 , it is necessary to investigate the SO 2 removal performance of the spent CaO/Ca 12 Al 14 O 33 .…”

“…The sequence SO 2 /CO 2 capture performance of normal CaO-based adsorbents such as natural limestone, lime mud, and calcium magnesium acetate (CMA) have been analyzed in the published literatures. [18][19][20][21] Considering the relatively high cost of a modified CaO-based adsorbent such as CaO/Ca 12 Al 14 O 33 , it is necessary to investigate the SO 2 removal performance of the spent CaO/Ca 12 Al 14 O 33 . However, there are few reports that focus on this topic.…”

Solubility of sulfur dioxide in tetraglyme-NH4SCN ionic liquid: high absorption efficiency

“…At present, a limestone/lime based FGD method is the most widely used flue gas desulfurization technology in industrial practice. 4,5 However, this method produces a large amount of secondary pollution such as gypsum and industrial wastewater, along with low limestone utilization and poor selectivity, which is difficult to overcome. 6 Therefore, the development of new desulfurizers with good absorption capacity, selectivity, regenerability, thermal stability and an environmentally friendly nature has become one of the current research hotspots.…”