The feasibility of flue gas desulphurization （FGD） as concrete admixture was studied. A combined concrete admixture of the thermally-treated FGD gypsum and slag powder was explored. The FGD gypsum was roasted at 200...The feasibility of flue gas desulphurization （FGD） as concrete admixture was studied. A combined concrete admixture of the thermally-treated FGD gypsum and slag powder was explored. The FGD gypsum was roasted at 200℃ for 60 min and then mixed with the slag powder to form FGD gypsum-slag powder combined admixture in which the SO3 content was 3.5wt%. Cement was partially and equivalently replaced by slag powder alone or FGD gypsum-slag powder, at concentration of 25wt%, 40wt%, and 50wt%, respectively. The setting times, hydration products, total porosity and pore size distributions of the paste were determined. The compressive strength and drying shrinkage of cement mortar and concrete were also tested. The experimental results show that, in the presence of FGD gypsum, the setting times are much slower than those of pastes in the absence of FGD gypsum. The combination of FGD gypsum and slag powder provides synergistic benefits above that of slag powder alone. The addition of FGD gypsum provides benefit by promoting ettringite formation and forms a compact microstructure, increasing the compressive strength and reduces the drying shrinkage of cement mortar and concrete.展开更多
The relationship between the fine particles emitted after desulfurization and gypsum crystals in the desulfurization slurry was investigated,and the crystallization characteristics varying with the operation parameter...The relationship between the fine particles emitted after desulfurization and gypsum crystals in the desulfurization slurry was investigated,and the crystallization characteristics varying with the operation parameters and compositions of the desulfurization slurry were discussed.The results showed that the fine particles generated during the desulfurization process were closely related to the crystal characteristics in the desulfurization slurry by comparison of their morphology and elements. With the higher proportion of fine crystals in the desulfurization slurry,the number concentration of fine particles after desulfurization was increased and their particle sizes were smaller,indicating that the optimization of gypsum crystallization was beneficial for the reduction of the fine particle emission. The lower p H value and an optimal temperature of the desulfurization slurry were beneficial to restrain the generation of fine crystals in the desulfurization slurry. In addition,the higher concentrations of the Fe3＋ions and the F- ions in the desulfurization slurry both promoted the generation of fine crystals with corresponding change of the morphology and the effect of the Fe3＋ ions was more obvious.With the application of the desulfurization synergist additive,it was beneficial for the inhibition of fine crystals while the thinner crystals were generated.展开更多
石灰石/石膏湿法脱硫工艺中吸收剂石灰石(主要成分为CaCO_(3))反应活性低,在机组深度调峰快速升负荷、燃煤含硫变化大时净烟气SO_(2)排放质量浓度经常存在超标问题。为此以某电厂600 MW机组为例,采用一种新型高效脱硫吸收剂进行试验,结...石灰石/石膏湿法脱硫工艺中吸收剂石灰石(主要成分为CaCO_(3))反应活性低,在机组深度调峰快速升负荷、燃煤含硫变化大时净烟气SO_(2)排放质量浓度经常存在超标问题。为此以某电厂600 MW机组为例,采用一种新型高效脱硫吸收剂进行试验,结果表明:新型高效脱硫吸收剂的加入可在3min内快速提高烟气脱硫(flue gas desulfurization,FGD)系统的脱硫效率,抑制SO_(2)排放质量浓度在快速升负荷的超标现象,同时可增加FGD系统最大出力,拓宽FGD系统对高硫分煤种的适应能力,提高电厂燃煤采购的灵活性。展开更多
基金Funded by the National Natural Science Foundation of China(Nos.51208370,51172164)the Doctoral Program of Higher Education of China(No.20110072120046)+1 种基金the Fundamental Research Funds for the Central Universities(No.0500219170)the Opening Measuring Fund of LargeApparatus of Tongji University(No.0002012011)
文摘The feasibility of flue gas desulphurization （FGD） as concrete admixture was studied. A combined concrete admixture of the thermally-treated FGD gypsum and slag powder was explored. The FGD gypsum was roasted at 200℃ for 60 min and then mixed with the slag powder to form FGD gypsum-slag powder combined admixture in which the SO3 content was 3.5wt%. Cement was partially and equivalently replaced by slag powder alone or FGD gypsum-slag powder, at concentration of 25wt%, 40wt%, and 50wt%, respectively. The setting times, hydration products, total porosity and pore size distributions of the paste were determined. The compressive strength and drying shrinkage of cement mortar and concrete were also tested. The experimental results show that, in the presence of FGD gypsum, the setting times are much slower than those of pastes in the absence of FGD gypsum. The combination of FGD gypsum and slag powder provides synergistic benefits above that of slag powder alone. The addition of FGD gypsum provides benefit by promoting ettringite formation and forms a compact microstructure, increasing the compressive strength and reduces the drying shrinkage of cement mortar and concrete.
基金supported by the National Natural Science Foundation of China(No.21276049)the National Basic Research Program of China(973 Program)(No.2013CB228505)the Science and Technology Support Program of Jiangsu(No.BE2014856) for their financial support
文摘The relationship between the fine particles emitted after desulfurization and gypsum crystals in the desulfurization slurry was investigated,and the crystallization characteristics varying with the operation parameters and compositions of the desulfurization slurry were discussed.The results showed that the fine particles generated during the desulfurization process were closely related to the crystal characteristics in the desulfurization slurry by comparison of their morphology and elements. With the higher proportion of fine crystals in the desulfurization slurry,the number concentration of fine particles after desulfurization was increased and their particle sizes were smaller,indicating that the optimization of gypsum crystallization was beneficial for the reduction of the fine particle emission. The lower p H value and an optimal temperature of the desulfurization slurry were beneficial to restrain the generation of fine crystals in the desulfurization slurry. In addition,the higher concentrations of the Fe3＋ions and the F- ions in the desulfurization slurry both promoted the generation of fine crystals with corresponding change of the morphology and the effect of the Fe3＋ ions was more obvious.With the application of the desulfurization synergist additive,it was beneficial for the inhibition of fine crystals while the thinner crystals were generated.
文摘石灰石/石膏湿法脱硫工艺中吸收剂石灰石(主要成分为CaCO_(3))反应活性低,在机组深度调峰快速升负荷、燃煤含硫变化大时净烟气SO_(2)排放质量浓度经常存在超标问题。为此以某电厂600 MW机组为例,采用一种新型高效脱硫吸收剂进行试验,结果表明:新型高效脱硫吸收剂的加入可在3min内快速提高烟气脱硫(flue gas desulfurization,FGD)系统的脱硫效率,抑制SO_(2)排放质量浓度在快速升负荷的超标现象,同时可增加FGD系统最大出力,拓宽FGD系统对高硫分煤种的适应能力,提高电厂燃煤采购的灵活性。
