石灰石-石膏湿法烟气脱硫(wet flue gas desulfurization,WFGD)工艺具有吸收剂来源广、成本低、脱硫效率高等优点,成为应用最广泛的烟气脱硫工艺。湿法脱硫过程中,燃煤烟气在喷淋浆液的洗涤作用下不仅能高效脱除SO2而且可以协同去除细...石灰石-石膏湿法烟气脱硫(wet flue gas desulfurization,WFGD)工艺具有吸收剂来源广、成本低、脱硫效率高等优点,成为应用最广泛的烟气脱硫工艺。湿法脱硫过程中,燃煤烟气在喷淋浆液的洗涤作用下不仅能高效脱除SO2而且可以协同去除细颗粒物,但同时存在石灰浆液夹带导致出口颗粒物浓度增加的问题。本文首先综述了湿法脱硫的应用现状,对比了湿法脱硫系统前后细颗粒物物性变化,然后概述了应用于湿法脱硫协同去除细颗粒物的新方法,包括脱硫塔内部结构调整以及促进细颗粒物凝聚长大,同时分析了湿法脱硫工艺中采用荷电细水雾吸附细颗粒物并增益脱除SO2的可行性,以期为燃煤电厂细颗粒物排放控制提供借鉴。最后指出未来湿法脱硫技术不仅要实现高脱硫效率,而且能有效脱除未被静电除尘器脱除的细颗粒物,湿法脱硫技术的发展趋势是多种技术耦合实现多污染物的协同脱除。展开更多
Selective catalytic reduction(SCR) denitration may increase the emission of NH4+and NH3.The removal and transformation characteristics of ammonium sulfate aerosols and ammonia slip during the wet flue gas desulfurizat...Selective catalytic reduction(SCR) denitration may increase the emission of NH4+and NH3.The removal and transformation characteristics of ammonium sulfate aerosols and ammonia slip during the wet flue gas desulfurization(WFGD) process, as well as the effect of desulfurization parameters, were investigated in an experimental system equipped with a simulated SCR flue gas generation system and a limestone-based WFGD system.The results indicate that the ammonium sulfate aerosols and ammonia slip in the flue gas from SCR can be partly removed by slurry scrubbing, while the entrainment and evaporation of desulfurization slurry with accumulated NH4+will generate new ammoniumcontaining particles and gaseous ammonia.The ammonium-containing particles formed by desulfurization are not only derived from the entrainment of slurry droplets, but also from the re-condensation of gaseous ammonia generated by slurry evaporation.Therefore,even if the concentration of NH4+in the desulfurization slurry is quite low, a high level of NH4+was still contained in the fine particles at the outlet of the scrubber.When the accumulated NH4+in the desulfurization slurry was high enough, the WFGD system promoted the conversion of NH3 to NH4+and increased the additional emission of primary NH4+aerosols.With the decline of the liquid/gas ratio and flue gas temperature, the removal efficiency of ammonia sulfate aerosols increased, and the NH4+emitted from entrainment and evaporation of the desulfurization slurry decreased.In addition, the volatile ammonia concentration after the WFGD system was reduced with the decrease of the NH4+concentration and p H values of the slurry.展开更多
文摘石灰石-石膏湿法烟气脱硫(wet flue gas desulfurization,WFGD)工艺具有吸收剂来源广、成本低、脱硫效率高等优点,成为应用最广泛的烟气脱硫工艺。湿法脱硫过程中,燃煤烟气在喷淋浆液的洗涤作用下不仅能高效脱除SO2而且可以协同去除细颗粒物,但同时存在石灰浆液夹带导致出口颗粒物浓度增加的问题。本文首先综述了湿法脱硫的应用现状,对比了湿法脱硫系统前后细颗粒物物性变化,然后概述了应用于湿法脱硫协同去除细颗粒物的新方法,包括脱硫塔内部结构调整以及促进细颗粒物凝聚长大,同时分析了湿法脱硫工艺中采用荷电细水雾吸附细颗粒物并增益脱除SO2的可行性,以期为燃煤电厂细颗粒物排放控制提供借鉴。最后指出未来湿法脱硫技术不仅要实现高脱硫效率,而且能有效脱除未被静电除尘器脱除的细颗粒物,湿法脱硫技术的发展趋势是多种技术耦合实现多污染物的协同脱除。
基金supported by the National Natural Science Foundation of China(Nos.51576039 and 51576039).
文摘Selective catalytic reduction(SCR) denitration may increase the emission of NH4+and NH3.The removal and transformation characteristics of ammonium sulfate aerosols and ammonia slip during the wet flue gas desulfurization(WFGD) process, as well as the effect of desulfurization parameters, were investigated in an experimental system equipped with a simulated SCR flue gas generation system and a limestone-based WFGD system.The results indicate that the ammonium sulfate aerosols and ammonia slip in the flue gas from SCR can be partly removed by slurry scrubbing, while the entrainment and evaporation of desulfurization slurry with accumulated NH4+will generate new ammoniumcontaining particles and gaseous ammonia.The ammonium-containing particles formed by desulfurization are not only derived from the entrainment of slurry droplets, but also from the re-condensation of gaseous ammonia generated by slurry evaporation.Therefore,even if the concentration of NH4+in the desulfurization slurry is quite low, a high level of NH4+was still contained in the fine particles at the outlet of the scrubber.When the accumulated NH4+in the desulfurization slurry was high enough, the WFGD system promoted the conversion of NH3 to NH4+and increased the additional emission of primary NH4+aerosols.With the decline of the liquid/gas ratio and flue gas temperature, the removal efficiency of ammonia sulfate aerosols increased, and the NH4+emitted from entrainment and evaporation of the desulfurization slurry decreased.In addition, the volatile ammonia concentration after the WFGD system was reduced with the decrease of the NH4+concentration and p H values of the slurry.
