《燃烧流体力学》（英文版）Chapter 5 fluidization

煤烧圆家重点实验宝 Chapter 5 Fluidization §1. Introduction I. History 921.12.16, Fritz Winkle observed the phenomena of fluidization and developed the gasifigator 1939 arren Lewis and edwin gillil and discovered the technique of catalytic cracking with fast fluidization 1960s Douglass elliott began to use fluidized bed to produce steam 1982 Lurgi company set up first CFB 84MW National Lab, of Coal Combustion. HUST Wuhan 430074P R CHINA E-mail:pcbnlcc@hust.edu.cn

NL CC National Lab. of Coal Combustion, HUST Wuhan 430074, P. R. CHINA E-mail: pcbnlcc@hust.edu.cn Chapter 5 Fluidization §1. Introduction 1. History 1921.12.16, Fritz Winkle observed the phenomena of fluidization and developed the gasifigator. 1939. Warren Lewis and Edwin Gillil and discovered the technique of catalytic cracking with fast fluidization. 1960’s Douglass Elliott began to use fluidized bed to produce steam. 1982 Lurgi company set up first CFB 84MW

煤量甏圆家重点实验宝 2. Comparison of Different Kinds of boilers 特性炉排燃烧鼓泡床循环床煤粉炉 床高或燃料 燃烧区高度(m)0.2 1-215-4027-45 截面风速(m/s)1.2 1.5-2.54-8 4-6 过量空气(%)20-30 20-2510-2015-30 截面热负荷 MWm2)0.5-1.5 0.5-1.53-5 National Lab, of Coal Combustion. HUST Wuhan 430074 P R CHINA E-mail:pcbnlcc@hust.edu.cn

NL CC National Lab. of Coal Combustion, HUST Wuhan 430074, P. R. CHINA E-mail: pcbnlcc@hust.edu.cn 2. Comparison of Different Kinds of Boilers 特性 炉排燃烧 鼓泡床 循环床 煤粉炉 床高或燃料 燃烧区高度（m) 0.2 1 - 2 15 - 40 27 - 45 截面风速（m/s) 1.2 1.5 - 2.5 4-8 4 - 6 过量空气（%） 20-30 20-25 10-20 15-30 截面热负荷 （MW/m2 ) 0.5-1.5 0.5-1.5 3-5 4-6

煤烧圆家重点实验宝 特性炉排燃烧鼓泡床循环床煤粉炉 煤的粒度(mm)6-326以下6以下0.1以下 负荷调节比例4:1 燃烧效率(%)85-9090-9695-99 99 No排放(ppm)400-600300-40050-200400-600 炉内脱硫效率 80-9080-90低 National Lab, of Coal Combustion. HUST Wuhan 430074 P R CHINA E-mail:pcbnlcc@hust.edu.cn

NL CC National Lab. of Coal Combustion, HUST Wuhan 430074, P. R. CHINA E-mail: pcbnlcc@hust.edu.cn 特性 炉排燃烧 鼓泡床 循环床 煤粉炉 煤的粒度（mm) 6-32 6以下 6以下 0.1以下 负荷调节比例 4：1 3：1 3-4：1 燃烧效率（%） 85-90 90-96 95-99 99 Nox排放（ppm) 400-600 300-400 50-200 400-600 炉内脱硫效率 （%) 80-90 80-90 低

煤量甏圆家重点实验宝 3. Characteristics of Fluidization Combustion 1)Wide fuel application 2) High efficiency of desulphuration 3)Low NOx emission 4 )Large charge regulation range National Lab, of Coal Combustion. HUST Wuhan 430074 P R CHINA E-mail:pcbnlcc@hust.edu.cn

NL CC National Lab. of Coal Combustion, HUST Wuhan 430074, P. R. CHINA E-mail: pcbnlcc@hust.edu.cn 3. Characteristics of Fluidization Combustion 1) Wide fuel application; 2) High efficiency of desulphuration; 3) Low NOx emission; 4) Large charge regulation range

煤烧圆家重点实验宝 固定床 流 鼓泡 柱塞 流态化 具有气力输 流态化 流态化 的稀相流态 气体 气体 气体 气体 气体 气体 (b) (c) (f) 图2-1气固接触形式 10 National Lab, of Coal Combustion. HUST Wuhan 430074 P R CHINA E-mail:pcbnlcc@hust.edu.cn

NL CC National Lab. of Coal Combustion, HUST Wuhan 430074, P. R. CHINA E-mail: pcbnlcc@hust.edu.cn

据烧自重 「气中温分离循环流化床 图9下排气分离器循环床锅炉 L燃烧室2高温过热器3.低温过热器 4.省煤器 7.透灰器风箱 热照下气风分

NL CC National Lab. of Coal Combustion, HUST Wuhan 430074, P. R. CHINA E-mail: pcbnlcc@hust.edu.cn National Lab. of Coal Combustion, HUST Wuhan 430074, P. R. CHINA E-mail: pcbnlcc@hust.edu.cn NLCC 下排气中温分离循环流化床

煤量甏圆家重点实验宝 §2. Hydrodynamics 1. Fluidization Region 1)Packed bed(fixed bed) no relative move between particles △P 150 2 F+1751-20 (5-1) Where o -spherisity of particles surface of sphere with same volume as particle/real surface National Lab, of Coal Combustion. HUST Wuhan 430074 P R CHINA E-mail:pcbnlcc@hust.edu.cn

NL CC National Lab. of Coal Combustion, HUST Wuhan 430074, P. R. CHINA E-mail: pcbnlcc@hust.edu.cn §2. Hydrodynamics 1. Fluidization Region 1) Packed bed (fixed bed) no relative move between particles ( ) ( ) p f g p d U d U L P         2 2 2 3 2 1 1.75 1 150 − + − =  (5-1) Where  - spherisity of particles = surface of sphere with same volume as particle/real surface

煤烧圆家重点实验宝 2) Bubbling bed F=△PA=AL(-E Pn-Pg(5-2) f From(5-1),(5-2) .5 Re L+CaR (5-3) Re mf Prvpp-pr go Ar For small particles, umb >umf mb=2.07exp(0.716F)d 0.06 0.347 pf (5-4) Where F is mass factor of particles with d 45um National Lab, of Coal Combustion. HUST Wuhan 430074 P R CHINA E-mail:pcbnlcc@hust.edu.cn

NL CC National Lab. of Coal Combustion, HUST Wuhan 430074, P. R. CHINA E-mail: pcbnlcc@hust.edu.cn 2) Bubbling bed F = PA = AL(1− )( p −  f )g (5-2) From (5-1), (5-2)   ( ) 2 3 1 0.5 2 2 1 Re , Re      p mf  f f p f p mf mf gd Ar d U C C Ar C − = = = + − (5-3) For small particles, umb > umf ( ) ( ) 0.06 0.347 umb = 2.07exp 0.716F dp  f /  (5-4) Where F is mass factor of particles with dp < 45m

煤量甏圆家重点实验宝 3)S pouted bed condition: D max >0.6DB minimum spout velocity Us=Umf+0.07(gD). 5(5-5) 4) Turbulent bed Initial velocity of transition =30/4-0171 Terminal velocity of transition Vk=70V24-07 National Lab, of Coal Combustion. HUST Wuhan 430074 P R CHINA E-mail:pcbnlcc@hust.edu.cn

NL CC National Lab. of Coal Combustion, HUST Wuhan 430074, P. R. CHINA E-mail: pcbnlcc@hust.edu.cn 3) Spouted bed condition: Dbmax > 0.6DB minimum spout velocity Usl = Umf + 0.07(gD)0.5 (5-5) 4) Turbulent bed Initial velocity of transition Uc = 3.0  p d p − 0.17 Terminal velocity of transition Uk = 7.0  p d p − 0.77

煤烧圆家重点实验宝 Note: In the above mentioned states, the particles move within certain height above distributor 5)Fast Fluidization(Circulating Fluidization) uf-u u Properties axis: s distribution radii: core -annular flow local: cluster 6) Fluidization Figure National Lab, of Coal Combustion. HUST Wuhan 430074 P R CHINA E-mail:pcbnlcc@hust.edu.cn

NL CC National Lab. of Coal Combustion, HUST Wuhan 430074, P. R. CHINA E-mail: pcbnlcc@hust.edu.cn Note: In the above mentioned states, the particles move within certain height above distributor. 5) Fast Fluidization (Circulating Fluidization) uf - up > ut Properties: axis: S distribution radii: core -annular flow local: cluster 6) Fluidization Figure