The Ontario Hydro Method (OHM) recommended by the United States EnvironmentalProtection Agency (EPA) was used to determine mercury speciation in the combustionflue gas across wet FGD systems.Four coal-fired units with...The Ontario Hydro Method (OHM) recommended by the United States EnvironmentalProtection Agency (EPA) was used to determine mercury speciation in the combustionflue gas across wet FGD systems.Four coal-fired units with wet FGD systemswere chosen to evaluate mercury speciation and mercury removal efficiencies throughthese wet FGD systems.Chlorine content in coal had been suggested as a main factorthat affects mercury speciation in flue gas.It is shown that the higher the chlorine concentrationin coal is, the higher the percentage of oxidized mercury (Hg^(2+)) is removed in wetFGD systems, which can increase overall mercury removal efficiencies through wet FGDsystems.The selective catalyst reduction (SCR) system has a function of oxidizing elementalmercury (Hg^0) to oxidized mercury.A higher percentage of oxidized mercury in thetotal vapor mercury at the FGD inlet is observed when SCR is in service.Therefore, higheroverall mercury removal efficiencies through wet FGD are attained.Because of differentwet FGD operating conditions, there are different mercury removal efficiencies in differentunits.Elemental mercury reemission took place when a fraction of oxidized mercury absorbedin the slurry is reduced to elemental mercury, and Hg^0 is reemitted from stack,which results in decreases in mercury removal efficiencies through wet FGD systems.展开更多
The conventional wet FGD process has been applied in more than 85% units for SO2 removal in China. There are a great number of pollution components in the wastewater from wet FGD process,and the removal process of the...The conventional wet FGD process has been applied in more than 85% units for SO2 removal in China. There are a great number of pollution components in the wastewater from wet FGD process,and the removal process of these components is very complicated and difficult,especially the removal of heavy metals in the wastewater. Even if a foreign advanced technology was applied,it is still difficult to meet the discharge requirements of heavy metals in spite of its much higher investment,operation and maintenance cost than that from the domestic widely-used and simple wastewater treatment process. Under the background of increasingly stringent environmental requirements,to improve the existing wastewater treatment process or to change the existing wet FGD process has become extremely urgent.展开更多
MnO2 in pyrolusite can react with SO2 in flue gas and obtain by-product MnSO4· H2O. A pilot scale jet bubbling reactor was applied in this work. Different factors affecting both SO2 absorption efficiency and Mn2^...MnO2 in pyrolusite can react with SO2 in flue gas and obtain by-product MnSO4· H2O. A pilot scale jet bubbling reactor was applied in this work. Different factors affecting both SO2 absorption efficiency and Mn2^＋ extraction rate have been investigated, these factors include temperature of inlet gas flue, ration of liquid/solid mass flow rate（ L/S）, pyrolusite grade, and SO2 concentration in the inlet flue gas. In the meantime, the procedure of purification of absorption liquid was also discussed. Experiment results indicated that the increase of temperature from 30 to 70 K caused the increase of SO2 absorption efficiency from 81.4% to 91.2%. And when SO2 concentration in the inlet flue gas increased from 500 to 3000 ppm, SO2 absorption efficiency and Mn2^＋ extraction rate decreased from 98.1% to 82.2% and from 82.8% to 61.7%, respectively. The content of MnO2 in pyrolusite had a neglectable effect on SO2, absorption efficiency. Low L/S was good for both removal of SO2 and Mn2^＋ extraction. The absorption liquid was filtrated and purified to remove Si, Mg, Ca, Fe, Al and heavy metals, last product MnSO4· H2O was obtained which quality could reach China GB1622-86, the industry grade standards.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
文摘The Ontario Hydro Method (OHM) recommended by the United States EnvironmentalProtection Agency (EPA) was used to determine mercury speciation in the combustionflue gas across wet FGD systems.Four coal-fired units with wet FGD systemswere chosen to evaluate mercury speciation and mercury removal efficiencies throughthese wet FGD systems.Chlorine content in coal had been suggested as a main factorthat affects mercury speciation in flue gas.It is shown that the higher the chlorine concentrationin coal is, the higher the percentage of oxidized mercury (Hg^(2+)) is removed in wetFGD systems, which can increase overall mercury removal efficiencies through wet FGDsystems.The selective catalyst reduction (SCR) system has a function of oxidizing elementalmercury (Hg^0) to oxidized mercury.A higher percentage of oxidized mercury in thetotal vapor mercury at the FGD inlet is observed when SCR is in service.Therefore, higheroverall mercury removal efficiencies through wet FGD are attained.Because of differentwet FGD operating conditions, there are different mercury removal efficiencies in differentunits.Elemental mercury reemission took place when a fraction of oxidized mercury absorbedin the slurry is reduced to elemental mercury, and Hg^0 is reemitted from stack,which results in decreases in mercury removal efficiencies through wet FGD systems.
基金Supported by the National High Technology Research and Development Program of China(863 Program)(2013AA065403)Major Science and Technology Project of Fujian Province,China(2011HZ0005-1)+1 种基金International Science and Technology Cooperation Program(2010DFB93990)Natural Science Foundation of Fujian Province,China(2014J06020)
文摘The conventional wet FGD process has been applied in more than 85% units for SO2 removal in China. There are a great number of pollution components in the wastewater from wet FGD process,and the removal process of these components is very complicated and difficult,especially the removal of heavy metals in the wastewater. Even if a foreign advanced technology was applied,it is still difficult to meet the discharge requirements of heavy metals in spite of its much higher investment,operation and maintenance cost than that from the domestic widely-used and simple wastewater treatment process. Under the background of increasingly stringent environmental requirements,to improve the existing wastewater treatment process or to change the existing wet FGD process has become extremely urgent.
基金The Chinese Technology Department ( No. 85-912-04-01-02) the National Engineering Research Center for Flue Gas Desulfurization ( No.2001DC105003-1)
文摘MnO2 in pyrolusite can react with SO2 in flue gas and obtain by-product MnSO4· H2O. A pilot scale jet bubbling reactor was applied in this work. Different factors affecting both SO2 absorption efficiency and Mn2^＋ extraction rate have been investigated, these factors include temperature of inlet gas flue, ration of liquid/solid mass flow rate（ L/S）, pyrolusite grade, and SO2 concentration in the inlet flue gas. In the meantime, the procedure of purification of absorption liquid was also discussed. Experiment results indicated that the increase of temperature from 30 to 70 K caused the increase of SO2 absorption efficiency from 81.4% to 91.2%. And when SO2 concentration in the inlet flue gas increased from 500 to 3000 ppm, SO2 absorption efficiency and Mn2^＋ extraction rate decreased from 98.1% to 82.2% and from 82.8% to 61.7%, respectively. The content of MnO2 in pyrolusite had a neglectable effect on SO2, absorption efficiency. Low L/S was good for both removal of SO2 and Mn2^＋ extraction. The absorption liquid was filtrated and purified to remove Si, Mg, Ca, Fe, Al and heavy metals, last product MnSO4· H2O was obtained which quality could reach China GB1622-86, the industry grade standards.
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。
