清华大学：《化工原理》课程PPT教学课件（下）第二章 吸收小结ABSsummary

Summary: Absorption Knowledge Three main parts Part 1: how to achieve an absorption process? Part 2: how to determine the basic parameters of a packed column? Part 3: how to enhance an absorption process?

Summary: Absorption Knowledge: Three main parts: Part 1: how to achieve an absorption process? Part 2 : how to determine the basic parameters of a packed column? Part 3: how to enhance an absorption process?

Part 1: how to conduct an absorption process? (1) Dilute or Weak or lean gas fro esh quI d Regeneration olute rocess Plate column packed column ie. Stripping or desorption Rich gas Strong solute gas liquid and inert gas)

Part 1: how to conduct an absorption process?(1) absorption Rich gas (solute gas and inert gas) Dilute or lean gas Weak or fresh liquid Strong liquid Regeneration process ie. Stripping or desorption solute Plate column packed column

Part 1: how to conduct an absorption process? (2) Liguid Distributor and redist pac kil nus packing support Pocked packing cover FIGURE 23-1 Packed toy

Part 1: how to conduct an absorption process?(2) • Distributor and redistributor • packings • packing support • packing cover

Part 1: how to conduct an absorption process? 3) pacKings dumped packings stacked packings constructed packings porosity: 60-90% Lessing ring: fei eai fa) Berd sadie; (6)Intalox ad double-spiral ring: () tripe- spiral ring

Part 1: how to conduct an absorption process?(3) • packings – dumped packings – stacked packings – constructed packings • porosity: 60-90%

Part 2: how to determine the basic parameters of a packed column (Diameter and Height)? Diameter of packed tower Superficial gas velocity flooding velocity

Part 2 : how to determine the basic parameters of a packed column (Diameter and Height)? • Diameter of packed tower – Superficial gas velocity – flooding velocity

How to determine flooding velocity Counter L2 current flow and cocurrent flow B B L=0 Continous A hase and di Ispersed phase slope: 1.8 Loading point and flooding Velocity of gas oint

How to determine flooding velocity L=0 L1 L2 A A B B of gas Pressure drop Velocity of gas slope : 1.8 ? Counter current flow and cocurrent flow ? Continous phase and dispersed phase Loading point and flooding point

Height of packed tower(1) limiting gas/liquid ratio operating line and equilibrium line

Height of packed tower(1) • limiting gas/liquid ratio • operating line and equilibrium line

With the decrease of L YI L=11-2 Lmin X2 XI

X Y X2 Y2 Y1 X1 With the decrease of L…. L=1.1-2 Lmin

Height of packed tower(2) VY2+ L, X2 H Vdr= NA=(QdHaK (r-rs y dy Y,Ⅹ, OKays dh H Jr2OKay-y* QK aJy2 y-y* VYI L XI

V, Y2 L, X2 V, Y1 L, X1 Y, X, dH H * * * ( ) ( *) 1 2 1 2 Y Y dY K a V Y Y dY K a V H Y Y dY K a V dH VdY NA dHa K Y Y Y Y Y Y Y Y Y Y  − =  − =  − = − − = =  −   Height of packed tower(2)

Number of transfer units (NTU) height of a transfer unit(hTu) VY2 X2 H H OG OK.a Y,Ⅹ, dh y1 dy OG Y2Y一Y VYI L XI Kya: overall volumetric mass transfer coefficient based on gas component

Number of transfer units (NTU) & Height of a transfer unit(HTU) V, Y2 L, X2 V, Y1 L, X1 Y, X, dH H * 1 2 Y Y dY N K a V H Y Y OG Y OG − =  =  KYa: overall volumetric mass transfer coefficient based on gas component