石灰干式消化过程及机理研究
摘要
生石灰干式消化工艺对石灰粉的转化率、固体颗粒大小以及消石灰的比表面积和孔隙率都有很大影响,直接关系到脱硫剂品质的好坏。通过研究消化条件对脱硫剂结构和脱硫性能的影响,寻求最合适的消化条件,有助于提高烟气脱硫率。
本文通过正交实验和单因素实验方法,考察了水灰比、消化水初始温度、搅拌速度及消化时间等消化过程参数脱硫剂结构和脱硫性能的影响;通过物料和热量计算,研究生石灰干式消化工艺过程中热力学和动力学特征;通过向生石灰添加SiO_2、Fe_2O_3、Al_2O_3、MgO等物质,研究石灰干式消化过程中杂质种类和数量对石灰消化速度、脱硫剂物理结构特性的影响。
实验结果表明,以比表面积(S)和孔隙率(P)为特征参数,本研究体系中消化参数对工艺过程影响程度由大到小的顺序为:消化时间>水灰比>搅拌速度>消化水初始温度。在此基础上,研究得到的本体系优化的消化工艺参数范围为:消化时间5 min~10 min、水灰比1.3:1~1.6:1、搅拌速度300 r/min~400 r/min、消化水初始温度25℃~45℃。热力学计算表明,在最佳水灰比范围内,生石灰消化反应平衡常数大,消石灰含水率适中,具有最佳的理化性质,与实验结果一致。动力学计算表明,生石灰干式消化过程属于扩散控制,利用Carter方程基本上能够描述生石灰干式消化反应的机理过程。不同含量的石灰杂质对石灰消化过程的影响不一样,SiO_2组分含量在6.0 %~8.0 %,MgO的添加量在1.0 %左右,Fe_2O_3为2.0 %~3.0 %,Al_2O_3的加入量在1.0 %左右时,所得消化产物的物理结构性能较佳。
Dry slaking of quick lime impacts greatly on the conversion rate of lime, solid particle size, specific surface area and porosity, and determines the quality of the prepared desulfurization agent. The optimum conditions of the dry slaking can be obtained by the research of the influences of dry slaking technology on the structure and desulfurized property of desulfurization agent. And then, it can help to enhance desulfurization ratio during flue gas desulfurization.
This paper investigated the influences of factors, such as water/solid ratio, initial temperature of hydrating-water, agitation rate, and hydration time, on the structure and desulfurized property of dusulfurization agent by the methods of orthogonal experimental design and single factor experimental design. Thermodynamics and kinetics of this process were studied by methods of mass balance and enthalpy balance. The dry slaking velocity of quick lime and chemical-physical properties of desulfurization agent were studied on by adding additives such as silicon dioxide, ferric oxide, alumina, and magnesia, into the process with different species and amounts of additives.
In this research, specific surface area and porosity were used as characteristic parameters of white lime. Experimental results indicated that the influence of these factors arranged in a decreasing order is hydration time, water/solid ratio, agitation rate and initial temperature of hydrating-water. Accordingly, the optimal values of the procedure factors obtained from this system are 5 min~10 min of slaking time, 1.3:1~1.6:1 of water/solid ratio, 300 r/min~400 r/min of agitation rate, and 25℃~45℃of initial temperature of hydration water. Thermodynamic calculations show that in the range of the optimum water-cement ratio, the equilibrium constant of lime digestion was large, lime water content was moderate, with the best physical and chemical properties and consistent with the experimental results. Dynamics calculations show that the dry lime diffusion controlled the digestion process, lime carter equation could basically describe the reaction mechanism of dry digestion process. Different amounts of impurities added in lime had different effect on the digestive process. Impurities in a certain range were contribute to digestion. They can improve the structural performance of desulfurization agent, and improve the desulfurization performance. When SiO_2 content was in the 6.0 %~8.0 %, MgO was about 1.0 %, Fe_2O_3 was 2.0 %~3.0 % and Al_2O_3 was 1.0 %, the digestion products obtained better performance of the physical structure.
本文通过正交实验和单因素实验方法,考察了水灰比、消化水初始温度、搅拌速度及消化时间等消化过程参数脱硫剂结构和脱硫性能的影响;通过物料和热量计算,研究生石灰干式消化工艺过程中热力学和动力学特征;通过向生石灰添加SiO_2、Fe_2O_3、Al_2O_3、MgO等物质,研究石灰干式消化过程中杂质种类和数量对石灰消化速度、脱硫剂物理结构特性的影响。
实验结果表明,以比表面积(S)和孔隙率(P)为特征参数,本研究体系中消化参数对工艺过程影响程度由大到小的顺序为:消化时间>水灰比>搅拌速度>消化水初始温度。在此基础上,研究得到的本体系优化的消化工艺参数范围为:消化时间5 min~10 min、水灰比1.3:1~1.6:1、搅拌速度300 r/min~400 r/min、消化水初始温度25℃~45℃。热力学计算表明,在最佳水灰比范围内,生石灰消化反应平衡常数大,消石灰含水率适中,具有最佳的理化性质,与实验结果一致。动力学计算表明,生石灰干式消化过程属于扩散控制,利用Carter方程基本上能够描述生石灰干式消化反应的机理过程。不同含量的石灰杂质对石灰消化过程的影响不一样,SiO_2组分含量在6.0 %~8.0 %,MgO的添加量在1.0 %左右,Fe_2O_3为2.0 %~3.0 %,Al_2O_3的加入量在1.0 %左右时,所得消化产物的物理结构性能较佳。
Dry slaking of quick lime impacts greatly on the conversion rate of lime, solid particle size, specific surface area and porosity, and determines the quality of the prepared desulfurization agent. The optimum conditions of the dry slaking can be obtained by the research of the influences of dry slaking technology on the structure and desulfurized property of desulfurization agent. And then, it can help to enhance desulfurization ratio during flue gas desulfurization.
This paper investigated the influences of factors, such as water/solid ratio, initial temperature of hydrating-water, agitation rate, and hydration time, on the structure and desulfurized property of dusulfurization agent by the methods of orthogonal experimental design and single factor experimental design. Thermodynamics and kinetics of this process were studied by methods of mass balance and enthalpy balance. The dry slaking velocity of quick lime and chemical-physical properties of desulfurization agent were studied on by adding additives such as silicon dioxide, ferric oxide, alumina, and magnesia, into the process with different species and amounts of additives.
In this research, specific surface area and porosity were used as characteristic parameters of white lime. Experimental results indicated that the influence of these factors arranged in a decreasing order is hydration time, water/solid ratio, agitation rate and initial temperature of hydrating-water. Accordingly, the optimal values of the procedure factors obtained from this system are 5 min~10 min of slaking time, 1.3:1~1.6:1 of water/solid ratio, 300 r/min~400 r/min of agitation rate, and 25℃~45℃of initial temperature of hydration water. Thermodynamic calculations show that in the range of the optimum water-cement ratio, the equilibrium constant of lime digestion was large, lime water content was moderate, with the best physical and chemical properties and consistent with the experimental results. Dynamics calculations show that the dry lime diffusion controlled the digestion process, lime carter equation could basically describe the reaction mechanism of dry digestion process. Different amounts of impurities added in lime had different effect on the digestive process. Impurities in a certain range were contribute to digestion. They can improve the structural performance of desulfurization agent, and improve the desulfurization performance. When SiO_2 content was in the 6.0 %~8.0 %, MgO was about 1.0 %, Fe_2O_3 was 2.0 %~3.0 % and Al_2O_3 was 1.0 %, the digestion products obtained better performance of the physical structure.
引文
[1]党玉华,齐渊洪,王海风.烧结烟气脱硫技术[J].钢铁研究学报,2010,22(5):1
[2]孙胜奇,陈荣永,王平.我国二氧化硫烟气脱硫技术现状及进展[J].中国钼业,2005,29(1):44
[3]刘征建,张建良,杨天钧.烧结烟气脱硫技术的研究与发展[J].中国冶金,2009,19(2):1
[4]朱婷钰.烧结烟气净化技术[M].北京:化学工业出版社,2008
[5]刘昊宇.烧结烟气脱硫进展[J].工程技术
[6]陈健.烧结烟气脱硫方式的分析探讨[J].世界钢铁,2010,(3):1-2
[7]吴树新,关俊霞,贾俊芳,杨仁柱.钙基燃煤烟气脱硫剂的研究进展[J].唐山师范学院学报,2005,27(2):23
[8] Borgwardt, R H, Harvey R D. Properties of Carbonate Rocks Related to SO2 Reactivity. Env. Sci. Tech. 1972, 6(4)
[9]史学锋,冯波.流化床煤燃烧中的脱硫研究综述[J].电站系统工程,1998,14(6):18-22
[10]王宽幅,张秋望.烟气脱硫技术综述[J].今日科技,1995(8):3-4
[11]郭如新.氧化镁、氢氧化镁在环保领域中的应用[J].江苏化工,2004,32(2):2-4
[12]程乐鸣,刘妮,骆仲泱等.流化床燃烧脱硫剂反应活性的测试及其评价方法[J].电站系统工程,2002,18(2):8-10
[13] Yang R T, et al. Fluidized-bed Combustion of Coal with Lime Additives: Catalytic Sulfation of Lime with Iron Compounds and Coal Ash[J]. Env. Sci. Tech., 1978, 12(8): 121-123
[14]周俊虎,范浩杰.氧化钙燃烧固硫添加剂的研究[J].环境科学学报,1997,17(3):284-288
[15]范浩杰,姚强等.碱金属化合物添加剂对氧化钙固硫影响的实验研究[J].燃烧科学与技术,1997,3(1):105-109
[16] Hamer C A. Evaluation of SO2 Sorbent Utilization in Fluidized Beds [R]. CANMET Report,CM86-9E, 1986
[17] Ali Al-Shawabkeh, et al. Comparative Reactivity of Ca(OH)2-derived Oxides for SO2 Removal [J]. Journal of Chemical Engineering of Japan, 1994, 27(5)
[18] K Laursen, W Duo, J R Grace, et al. Sulfation and Reaction Characteristics of Nine Limestones [J]. Fuel, 2000, 79(200): 153-163
[19] E·席勒,L·W贝伦斯[西德]著.陆华,武洞明译.石灰[M].北京:中国建筑工业社,1981
[20]郭秀键.脱硫剂特性及石灰消化的试验研究[D].山东大学硕士学位论文,2005
[21] Hilja Lohmus, Ahto Rani. A tend to the production of calcium hydroxide and precipitated calcium carbonate with defined properties[J]. The Canadiam Journal of Chemical Engineering, 2002, 80: 10
[22]汪波.喷雾干燥法烟气脱硫工艺[J].环境保护,1995,(9):15-17
[23]王国庆,崔英德.轻质碳酸钙生产工艺[M].北京:化学工业出版社,1998
[24]张津莅.干法消石灰生产工艺技术[J].化工工程手册,1998,(1):5-7
[25]刘翼伯,魏金照,孙丽玲.胶凝材料[M].上海:同济大学出版社,1990
[26] Pavid G S, et al. Options are increasing for reducing emission of SO2 and NOx[J]. Power Engineering, 1988, 92(12): 30-34
[27]《化学工程手册》编辑委员会.流态化.化学工程手册(第20篇)[M].北京:化学工业出版社,1987
[28]叶春.回流式循环流化床烟气脱硫技术在火电厂的应用[J].中国电力,2004,30(3):85-86
[29]黎在时,刘卫平.德国WULFF公司的干法脱硫技术[J].中国环保产业,2002(21):74-76
[30] Ball M E, Smith D W, et al. LIFAC—控制的经济方法[A].潘东译.电站锅炉煤清洁燃烧技术译文集[C].北京:清华大学煤清洁燃烧国家工程研究中心,1998:1-8
[31]钟伟飞.石灰消化工艺参数及氢氧化钙溶解速率实验研究[D].浙江大学硕士论文,2004
[32] Ian M Ritchie, XuBingAn. The kinetics of lime slaking. Hydrometallurgy, 1990, 23: 377-396
[33]任露泉.实验优化设计与分析[M].2版.北京:高等教育出版社,2003
[34]郝素菊,张玉柱等.温升速率法测定高活性石灰的活性度[J].冶金分析,2008,28(8):19-22
[35]王轶.NID消化过程特点及生石灰活性的测定与分析[J].中国环保产业,2006,(3):26-27
[36]薛健.循环悬浮式半干法烟气脱硫工艺中石灰活性及干式消化性能的实验研究[D].浙江大学硕士论文,2006
[37] Potgieter, J.H., Potgieter, S.S., De Waal, D., 2003. An empirical study of factors in uencing lime slaking:II.In.uence of material and water composition. Water SA 29(2): 157-160
[38] Strdom, C.A., Potgieter, J.H., 1997. An investigation into the chemical nature of the reactivity of lime. In: Proceedings of the 10th International Chemistry of Cement Conference, Gothenburg, Sweden, vol. 2, paper no. 2, 49
[39] D E Giles, I M Ritchie, B A Xu. The kinetics of dissolution of slaked lime. Hydrometallurgy, 1993, 32: 119-128
[40] L Bernard, M Freche, J L Lacout, B Biscan. Modeling of the dissolution of calcium hydroxide in the preparation of hydroxyapatite by neutralization. Chem. Eng. Sci. 2000, 55: 5683-5692
[41] Johannsen K, Rademacher S. Modeling the kinetics of calcium hydroxide dissolution in water. Acta Hydrochimica et Hydrobiological, 1999, 27(2): 72-78
[42]卢寿慈.粉体技术手册[M].北京:化学工业出版社,2004
[43]赵文龄,李幸晓.生产消石灰粉的合理工艺参数[J].湖北省建材研究设计所,20-23
[44]朱炳辰.化学反应工程[M].北京:化学工业出版社,2004
[45]滕斌.半干法烟气脱硫的实验及机理研究[D].浙江大学博士学位论文,2004
[2]孙胜奇,陈荣永,王平.我国二氧化硫烟气脱硫技术现状及进展[J].中国钼业,2005,29(1):44
[3]刘征建,张建良,杨天钧.烧结烟气脱硫技术的研究与发展[J].中国冶金,2009,19(2):1
[4]朱婷钰.烧结烟气净化技术[M].北京:化学工业出版社,2008
[5]刘昊宇.烧结烟气脱硫进展[J].工程技术
[6]陈健.烧结烟气脱硫方式的分析探讨[J].世界钢铁,2010,(3):1-2
[7]吴树新,关俊霞,贾俊芳,杨仁柱.钙基燃煤烟气脱硫剂的研究进展[J].唐山师范学院学报,2005,27(2):23
[8] Borgwardt, R H, Harvey R D. Properties of Carbonate Rocks Related to SO2 Reactivity. Env. Sci. Tech. 1972, 6(4)
[9]史学锋,冯波.流化床煤燃烧中的脱硫研究综述[J].电站系统工程,1998,14(6):18-22
[10]王宽幅,张秋望.烟气脱硫技术综述[J].今日科技,1995(8):3-4
[11]郭如新.氧化镁、氢氧化镁在环保领域中的应用[J].江苏化工,2004,32(2):2-4
[12]程乐鸣,刘妮,骆仲泱等.流化床燃烧脱硫剂反应活性的测试及其评价方法[J].电站系统工程,2002,18(2):8-10
[13] Yang R T, et al. Fluidized-bed Combustion of Coal with Lime Additives: Catalytic Sulfation of Lime with Iron Compounds and Coal Ash[J]. Env. Sci. Tech., 1978, 12(8): 121-123
[14]周俊虎,范浩杰.氧化钙燃烧固硫添加剂的研究[J].环境科学学报,1997,17(3):284-288
[15]范浩杰,姚强等.碱金属化合物添加剂对氧化钙固硫影响的实验研究[J].燃烧科学与技术,1997,3(1):105-109
[16] Hamer C A. Evaluation of SO2 Sorbent Utilization in Fluidized Beds [R]. CANMET Report,CM86-9E, 1986
[17] Ali Al-Shawabkeh, et al. Comparative Reactivity of Ca(OH)2-derived Oxides for SO2 Removal [J]. Journal of Chemical Engineering of Japan, 1994, 27(5)
[18] K Laursen, W Duo, J R Grace, et al. Sulfation and Reaction Characteristics of Nine Limestones [J]. Fuel, 2000, 79(200): 153-163
[19] E·席勒,L·W贝伦斯[西德]著.陆华,武洞明译.石灰[M].北京:中国建筑工业社,1981
[20]郭秀键.脱硫剂特性及石灰消化的试验研究[D].山东大学硕士学位论文,2005
[21] Hilja Lohmus, Ahto Rani. A tend to the production of calcium hydroxide and precipitated calcium carbonate with defined properties[J]. The Canadiam Journal of Chemical Engineering, 2002, 80: 10
[22]汪波.喷雾干燥法烟气脱硫工艺[J].环境保护,1995,(9):15-17
[23]王国庆,崔英德.轻质碳酸钙生产工艺[M].北京:化学工业出版社,1998
[24]张津莅.干法消石灰生产工艺技术[J].化工工程手册,1998,(1):5-7
[25]刘翼伯,魏金照,孙丽玲.胶凝材料[M].上海:同济大学出版社,1990
[26] Pavid G S, et al. Options are increasing for reducing emission of SO2 and NOx[J]. Power Engineering, 1988, 92(12): 30-34
[27]《化学工程手册》编辑委员会.流态化.化学工程手册(第20篇)[M].北京:化学工业出版社,1987
[28]叶春.回流式循环流化床烟气脱硫技术在火电厂的应用[J].中国电力,2004,30(3):85-86
[29]黎在时,刘卫平.德国WULFF公司的干法脱硫技术[J].中国环保产业,2002(21):74-76
[30] Ball M E, Smith D W, et al. LIFAC—控制的经济方法[A].潘东译.电站锅炉煤清洁燃烧技术译文集[C].北京:清华大学煤清洁燃烧国家工程研究中心,1998:1-8
[31]钟伟飞.石灰消化工艺参数及氢氧化钙溶解速率实验研究[D].浙江大学硕士论文,2004
[32] Ian M Ritchie, XuBingAn. The kinetics of lime slaking. Hydrometallurgy, 1990, 23: 377-396
[33]任露泉.实验优化设计与分析[M].2版.北京:高等教育出版社,2003
[34]郝素菊,张玉柱等.温升速率法测定高活性石灰的活性度[J].冶金分析,2008,28(8):19-22
[35]王轶.NID消化过程特点及生石灰活性的测定与分析[J].中国环保产业,2006,(3):26-27
[36]薛健.循环悬浮式半干法烟气脱硫工艺中石灰活性及干式消化性能的实验研究[D].浙江大学硕士论文,2006
[37] Potgieter, J.H., Potgieter, S.S., De Waal, D., 2003. An empirical study of factors in uencing lime slaking:II.In.uence of material and water composition. Water SA 29(2): 157-160
[38] Strdom, C.A., Potgieter, J.H., 1997. An investigation into the chemical nature of the reactivity of lime. In: Proceedings of the 10th International Chemistry of Cement Conference, Gothenburg, Sweden, vol. 2, paper no. 2, 49
[39] D E Giles, I M Ritchie, B A Xu. The kinetics of dissolution of slaked lime. Hydrometallurgy, 1993, 32: 119-128
[40] L Bernard, M Freche, J L Lacout, B Biscan. Modeling of the dissolution of calcium hydroxide in the preparation of hydroxyapatite by neutralization. Chem. Eng. Sci. 2000, 55: 5683-5692
[41] Johannsen K, Rademacher S. Modeling the kinetics of calcium hydroxide dissolution in water. Acta Hydrochimica et Hydrobiological, 1999, 27(2): 72-78
[42]卢寿慈.粉体技术手册[M].北京:化学工业出版社,2004
[43]赵文龄,李幸晓.生产消石灰粉的合理工艺参数[J].湖北省建材研究设计所,20-23
[44]朱炳辰.化学反应工程[M].北京:化学工业出版社,2004
[45]滕斌.半干法烟气脱硫的实验及机理研究[D].浙江大学博士学位论文,2004
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