钙基脱硫剂煅烧特性及其孔结构模拟研究
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摘要
结合石灰石分解的动力学特性、晶体的烧结模型,建立石灰石同时煅烧和烧结模型,分析各种控速因素,对分解产物的孔隙结构参数进行研究。另外,在此基础上结合石灰石分解过程中CaO 晶体的成核机理和孔隙生成机理,采用Monte-Carlo 方法,对脱硫剂不同分解条件、不同煅烧时刻分解产物孔隙空间网络进行模拟构造,用图像直观描述其微观结构,显现脱硫剂煅烧过程中孔结构的变化情况,并对其进行分形分析。以石灰石煅烧过程中形成的孔隙结构的孔隙率和比表面积为参数,提出煅烧过程中的孔隙分布模型和孔长度分布模型,对脱硫剂煅烧过程中的孔隙分布进行分析研究。研究分析表明:所提出的模型能很好地吻合实验结果,这些方面的研究对于探讨脱硫剂脱硫机理和高温烧结机理具有重要的理论参考价值。
Based on the decomposition dynamics and sintering mechanism, a computation model simulating the decomposition of calcium carbonate and predicting the porosity and specific surface areas of product CaO is presented. Meanwhile,based on the theory of solid nucleation and pore formation and the above-mentioned decomposition model, a pore network formation model of CaO samples is also proposed by using a new discrete lattice and the Monte-Carlo method. The model can describe the micro-pore structure of CaO samples during the course of calcination, which is not yet found in published work. On the other hand, it is supposed that the pore size distribution is continuous and pore length changes with pore size. With the known porosity and specific surface areas during the calcination processing, a model describing the pore distribution is proposed. The specific surface areas and distribution density inside porous CaO examples are calculated using the models. The results are of agreement with the experimental datum. And these study have an important theory reference meanings on the desulfurizion and sintering mechanics of sorbents.
Based on the decomposition dynamics and sintering mechanism, a computation model simulating the decomposition of calcium carbonate and predicting the porosity and specific surface areas of product CaO is presented. Meanwhile,based on the theory of solid nucleation and pore formation and the above-mentioned decomposition model, a pore network formation model of CaO samples is also proposed by using a new discrete lattice and the Monte-Carlo method. The model can describe the micro-pore structure of CaO samples during the course of calcination, which is not yet found in published work. On the other hand, it is supposed that the pore size distribution is continuous and pore length changes with pore size. With the known porosity and specific surface areas during the calcination processing, a model describing the pore distribution is proposed. The specific surface areas and distribution density inside porous CaO examples are calculated using the models. The results are of agreement with the experimental datum. And these study have an important theory reference meanings on the desulfurizion and sintering mechanics of sorbents.
引文
[1]李萌堂.环境保护与节能. 西安交通大学出版社,1998:80~84
[2]U.S.EPA. Flue gas desulphurization technologies for control of sulfur oxides research. development and demonstration, EPA 1600/f-95/103
[3]张坤民,过孝民. 我国能源环境的形势与对策. 环境保护,1996(4):2~4
[4]郝吉明,贺克斌. 中国燃煤二氧化硫污染控制战略. 中国环境科学,1996,16(3):208~212
[5]Sotirchos S V, Zarkanitis S. . Inaccessible pore volume formation during sulfation of calcined limestone. AICHEJ, 1992,38:1536~1550
[6]张东晖. 分形介质的热传导,应用科学学报,2003,21(3):253~257
[7] Borgwardt, R. H. . Calcination kinetics and surface area of dispersed limestone particles. AICHEJ, 1985, 31(4):642-648
[8] Powell, E. K.., Surface area and morphologies of CaO produced by decomposition of large CaCO3 crystals in vacuum. . Commum. Am. Ceram. Soc,1982, March:42-44
[9] Ulerich, N. H,ONeill, E. P,Keaims, D. L. . A thermogravimetric study of the effect of pore volume-pore size distribution on the sulfation of calcined limestone. Thermochimica Acta, 1978,26:269-28
[10]Mandelbrot B.B. The fractal geometry of nature. San Francisco Freeman:1982
[11]郑瑛. 多孔CaO 孔隙结构的分形描述. 华中科技大学学报,2001(29):82~85
[12]Frisen W.I. and Laidlaw W.G. . Porosimetry of fractal surfaces. J Colloid Interface Sci, 1993(160):226~235
[13]Silcox,G.D. . Amathematical model for the flash calcinations of dispersed CaCO3 and Ca(OH)2 particles. Ind. Eng.Chem.Res.,1989(28):155~160
[14]German, R.W. and Munir, Z.A. . Surface area reduction during isothermal sintering. . J. Am.Ceram. Soc, 1976(59):379~383
[15]Gullett B.K.and Bruce K.R. . Pore distribution changes of calcium-based sorbents reacting with surfur dioxide. AICHEJ. 1987(33):1791~1726
[16]Ghosh-Dastidar, A.,Mahuli, S., Agnihotri, R., Fan, L-S. . ltrafast Calcination and sintering of Ca(OH)2 powder: experimental and modeling. Chemical Engineering Science, 1995, 50(13):2029-2040
[17]Hung S.J.. Correlation and characterization of porous solids by fractal dimension and porosity. Physica A,1999(274):419~432
[18]Kerl F.J. . Diffusion and reaction in pore networks. Catalysis Today, 1999(53): 245~258
[19] 王国金. 石灰石固硫的数学模拟研究. 热力发电,1996(5):3-10
[20] 李徇天. 循环流化床脱硫脱硝及灰渣冷却余热利用:[博士学位论文] . 杭州:浙江大学,1989
[21] 陈德珍,张鹤声. 模拟石灰颗粒干式除酸的分形Bethe 孔网模型. 同济大学学报(自然科学版),2000(1)
[22] 缪明烽. 钙基脱硫剂非线性孔结构及其硫化活性的研究:[博士学位论文] . 南京:东南大学,2001:46～50
[23] F.Garcia-Labiano. Calcination of calcium-based sorbents at pressure in a broad range of CO2 concentrations. Chem. Eng. Sci. . 2002(57):2381-2393.
[24] 谢健云,傅维标. 碳酸钙颗粒煅烧过程的统一数学模型. 燃烧科学与技术,2002,8(3):270-271
[25] Hu Naiyi. Scaroni A lan W. Calcination of pulverized limestone particles under furnace injection conditons. Fuel, 1996(75):177-186
[26] Sumana Keener, Khang Soon2jai. A structural pore development model for calcinations. Chem Eng Canm, 1992(117):279-291
[27] M urthyM S, Harish B R, Rajanandam K S etal. Investigation on the kinetics of thermal decomposition of calcium carbonate. J Thermal Anal. 1994(37):1533-1543
[28] T.Rajeswara. . Kinetics of Calcium Carbonate Decompsition[J]. . Chem Eng Res Des, 67,January 1989:38-47
[29] Irfan Ar, Giilsen Dogu. Calcination kinetics of high purity limestones. Chemical Engineering Journal. 2001(83):131~137
[30]Borgwardt R H. . Sintering of nascent calcium oxide. Chem Eng S ci, 1989(44):53-63
[31] C. Fifus. Heat and mass transfer with phase change in a porous structure partially heated: continuum model and pore network simulations. Internation Journal of Heat and Mass Transfer, 1999(42):2557~2569
[32] 孙康. 宏观反应动力学及其解析方法. 冶金工业出版社,1998
[33] F.Demir. Calcination kinetic of magnesite from thermogravimetric data. Trans I chemE, 2003(81):618~622
[34] J.Agnew. The simultaneous calcinations and sintering of calcium based sorbents under a combustion atmosphere. Fuel, 2000(79):1515~1523
[35] K.Laursen. Sulfation and reactivation characteristics of nine limestones. Fuel,2000(79):153~165
[36] Diego Barletta. Modelling the SO_2 limestone reaction under periodically changing oxidizing/reducing conditions: the influence of cycle time on reaction rate. Chem. Eng. Sci , 2002(57):631~641
[37] H.Lir, S.Katagiri, U.Kaneko,K.Okazaki. Sulfation behavior of limestone under high CO2 comcentration in O2/CO2 coal combusion. Fuel, 2000(79):945~953
[38]刘妮. 钙基脱硫剂反应性能评价体系及反应机理的研究:[博士学位论文] . 杭州:浙江大学,2002
[39]Neimark A.V. . Calculating surface fractal dimensions of adsorbents, Adsorption Sci. and Technol. . 1990(7):210~219
[40]Pfeifer P. Structure Analysis of Porous Solids From Presorbed Films. Langmuir, 1991(7): 2833~2835
[41]Neimark A.V. . A new approach to the determination of the sreface fractal dimension of porous solods. Physical A, 1992(191):258~260
[42]Zhang B. Determination of the surface fractal dimension for porous media by mercury porosimetry. Ind.Eng.Chem.Res, 1995(34):1383~1386
[43]Wang F. Determination of the surface fractal dimension for porous media by capillary condensation. Ind.Eng.Chem.Res, 1997(36):1598~1602
[44] Hung S.J.,et al. Correlation and characterization of porous solids by fractal dimension and porosity. Physica A, 1999(274):419~432
[45] Keil F.J.. Diffusion and reaction in pore networks. Catalysis Today. 1999(53):245~258
[46] Bray Y.K. . Three-dimension pore network sumulation of drying in capillary porous media. Inter. J of Heat and Mass Transfer, 1999(42):4207~4224
[47]Milne C.R. . Calcinations and simtering models for application to high temperature short sulfation of calcium based sorbents. Ind.Eng Chem.Res. 1990(29):139~149
[48]Guo X.Y. . Monte carlo simulation of first-order diffusion-limited reaction within three-dimensinal porous pellets. Chinese J. Chem. Eng., 2003(11): 472~476
[49]武增华. 烧结程度对CaO固硫反应转化率及动力学参数的影响. 燃料化学学报,2001(3):273～276
[50]马奕. 高温燃煤脱硫机理研究及微观物化分析:[博士学位论文] . 杭州:浙江大学,2003
[51] 冯志刚. 图像的分形维数计算方法及其应用. 江苏理工大学学报(自然科学版),2001(22):92~95
[52] 格冒格S J,辛K S w.吸附比表面与孔隙率. 北京:化学工业出版社,1989
[53] Simons G A , Small pore closure and the deaction of the limestone sulfation reaction. AICHEJ.1986,32(9):1491~1499
[54]刘煜. 多孔氧化钙孔结构特征的数学描述与分析. 中国电机工程学报,2002(22):145~149
[55] Friesen W.I. .,Porosimetry of fractal surfaces. J Colloid Interface Sci, 1993(160):226~235
[56]程世庆. 钙基脱硫剂微观结构特性与流化床燃烧脱硫试验研究: [博士学位论文]. 杭州:浙江大学,2003
[2]U.S.EPA. Flue gas desulphurization technologies for control of sulfur oxides research. development and demonstration, EPA 1600/f-95/103
[3]张坤民,过孝民. 我国能源环境的形势与对策. 环境保护,1996(4):2~4
[4]郝吉明,贺克斌. 中国燃煤二氧化硫污染控制战略. 中国环境科学,1996,16(3):208~212
[5]Sotirchos S V, Zarkanitis S. . Inaccessible pore volume formation during sulfation of calcined limestone. AICHEJ, 1992,38:1536~1550
[6]张东晖. 分形介质的热传导,应用科学学报,2003,21(3):253~257
[7] Borgwardt, R. H. . Calcination kinetics and surface area of dispersed limestone particles. AICHEJ, 1985, 31(4):642-648
[8] Powell, E. K.., Surface area and morphologies of CaO produced by decomposition of large CaCO3 crystals in vacuum. . Commum. Am. Ceram. Soc,1982, March:42-44
[9] Ulerich, N. H,ONeill, E. P,Keaims, D. L. . A thermogravimetric study of the effect of pore volume-pore size distribution on the sulfation of calcined limestone. Thermochimica Acta, 1978,26:269-28
[10]Mandelbrot B.B. The fractal geometry of nature. San Francisco Freeman:1982
[11]郑瑛. 多孔CaO 孔隙结构的分形描述. 华中科技大学学报,2001(29):82~85
[12]Frisen W.I. and Laidlaw W.G. . Porosimetry of fractal surfaces. J Colloid Interface Sci, 1993(160):226~235
[13]Silcox,G.D. . Amathematical model for the flash calcinations of dispersed CaCO3 and Ca(OH)2 particles. Ind. Eng.Chem.Res.,1989(28):155~160
[14]German, R.W. and Munir, Z.A. . Surface area reduction during isothermal sintering. . J. Am.Ceram. Soc, 1976(59):379~383
[15]Gullett B.K.and Bruce K.R. . Pore distribution changes of calcium-based sorbents reacting with surfur dioxide. AICHEJ. 1987(33):1791~1726
[16]Ghosh-Dastidar, A.,Mahuli, S., Agnihotri, R., Fan, L-S. . ltrafast Calcination and sintering of Ca(OH)2 powder: experimental and modeling. Chemical Engineering Science, 1995, 50(13):2029-2040
[17]Hung S.J.. Correlation and characterization of porous solids by fractal dimension and porosity. Physica A,1999(274):419~432
[18]Kerl F.J. . Diffusion and reaction in pore networks. Catalysis Today, 1999(53): 245~258
[19] 王国金. 石灰石固硫的数学模拟研究. 热力发电,1996(5):3-10
[20] 李徇天. 循环流化床脱硫脱硝及灰渣冷却余热利用:[博士学位论文] . 杭州:浙江大学,1989
[21] 陈德珍,张鹤声. 模拟石灰颗粒干式除酸的分形Bethe 孔网模型. 同济大学学报(自然科学版),2000(1)
[22] 缪明烽. 钙基脱硫剂非线性孔结构及其硫化活性的研究:[博士学位论文] . 南京:东南大学,2001:46～50
[23] F.Garcia-Labiano. Calcination of calcium-based sorbents at pressure in a broad range of CO2 concentrations. Chem. Eng. Sci. . 2002(57):2381-2393.
[24] 谢健云,傅维标. 碳酸钙颗粒煅烧过程的统一数学模型. 燃烧科学与技术,2002,8(3):270-271
[25] Hu Naiyi. Scaroni A lan W. Calcination of pulverized limestone particles under furnace injection conditons. Fuel, 1996(75):177-186
[26] Sumana Keener, Khang Soon2jai. A structural pore development model for calcinations. Chem Eng Canm, 1992(117):279-291
[27] M urthyM S, Harish B R, Rajanandam K S etal. Investigation on the kinetics of thermal decomposition of calcium carbonate. J Thermal Anal. 1994(37):1533-1543
[28] T.Rajeswara. . Kinetics of Calcium Carbonate Decompsition[J]. . Chem Eng Res Des, 67,January 1989:38-47
[29] Irfan Ar, Giilsen Dogu. Calcination kinetics of high purity limestones. Chemical Engineering Journal. 2001(83):131~137
[30]Borgwardt R H. . Sintering of nascent calcium oxide. Chem Eng S ci, 1989(44):53-63
[31] C. Fifus. Heat and mass transfer with phase change in a porous structure partially heated: continuum model and pore network simulations. Internation Journal of Heat and Mass Transfer, 1999(42):2557~2569
[32] 孙康. 宏观反应动力学及其解析方法. 冶金工业出版社,1998
[33] F.Demir. Calcination kinetic of magnesite from thermogravimetric data. Trans I chemE, 2003(81):618~622
[34] J.Agnew. The simultaneous calcinations and sintering of calcium based sorbents under a combustion atmosphere. Fuel, 2000(79):1515~1523
[35] K.Laursen. Sulfation and reactivation characteristics of nine limestones. Fuel,2000(79):153~165
[36] Diego Barletta. Modelling the SO_2 limestone reaction under periodically changing oxidizing/reducing conditions: the influence of cycle time on reaction rate. Chem. Eng. Sci , 2002(57):631~641
[37] H.Lir, S.Katagiri, U.Kaneko,K.Okazaki. Sulfation behavior of limestone under high CO2 comcentration in O2/CO2 coal combusion. Fuel, 2000(79):945~953
[38]刘妮. 钙基脱硫剂反应性能评价体系及反应机理的研究:[博士学位论文] . 杭州:浙江大学,2002
[39]Neimark A.V. . Calculating surface fractal dimensions of adsorbents, Adsorption Sci. and Technol. . 1990(7):210~219
[40]Pfeifer P. Structure Analysis of Porous Solids From Presorbed Films. Langmuir, 1991(7): 2833~2835
[41]Neimark A.V. . A new approach to the determination of the sreface fractal dimension of porous solods. Physical A, 1992(191):258~260
[42]Zhang B. Determination of the surface fractal dimension for porous media by mercury porosimetry. Ind.Eng.Chem.Res, 1995(34):1383~1386
[43]Wang F. Determination of the surface fractal dimension for porous media by capillary condensation. Ind.Eng.Chem.Res, 1997(36):1598~1602
[44] Hung S.J.,et al. Correlation and characterization of porous solids by fractal dimension and porosity. Physica A, 1999(274):419~432
[45] Keil F.J.. Diffusion and reaction in pore networks. Catalysis Today. 1999(53):245~258
[46] Bray Y.K. . Three-dimension pore network sumulation of drying in capillary porous media. Inter. J of Heat and Mass Transfer, 1999(42):4207~4224
[47]Milne C.R. . Calcinations and simtering models for application to high temperature short sulfation of calcium based sorbents. Ind.Eng Chem.Res. 1990(29):139~149
[48]Guo X.Y. . Monte carlo simulation of first-order diffusion-limited reaction within three-dimensinal porous pellets. Chinese J. Chem. Eng., 2003(11): 472~476
[49]武增华. 烧结程度对CaO固硫反应转化率及动力学参数的影响. 燃料化学学报,2001(3):273～276
[50]马奕. 高温燃煤脱硫机理研究及微观物化分析:[博士学位论文] . 杭州:浙江大学,2003
[51] 冯志刚. 图像的分形维数计算方法及其应用. 江苏理工大学学报(自然科学版),2001(22):92~95
[52] 格冒格S J,辛K S w.吸附比表面与孔隙率. 北京:化学工业出版社,1989
[53] Simons G A , Small pore closure and the deaction of the limestone sulfation reaction. AICHEJ.1986,32(9):1491~1499
[54]刘煜. 多孔氧化钙孔结构特征的数学描述与分析. 中国电机工程学报,2002(22):145~149
[55] Friesen W.I. .,Porosimetry of fractal surfaces. J Colloid Interface Sci, 1993(160):226~235
[56]程世庆. 钙基脱硫剂微观结构特性与流化床燃烧脱硫试验研究: [博士学位论文]. 杭州:浙江大学,2003