CFB脱硫塔设计计算

Sheet 1 of 10 SCRUBBER DESIGN PACKED COLUMN Prepared by Column Tag No HCL Scrubber Checked by Job No 4506A Date Client JOL Project SR Plant 4 5 Input DataStream HCL Vap Packing type Intallox Saddles Packing size 25 mm Packing MOC PP Gas pr Drop m bed 15 mmWC m packing height 147 1 N m2 m Total packing height 3 2 m including all packed beds Gas Vapour Properties Gas Air flow rate 1000 kg hOR0 m3 h 0 2778 kg s 0 m3 s Gas pressure at entry 1 0000 atm Gas temperature at entry 30 00 oC 303 00 oK Gas Air mol weight 29 Component to be scrubbed Component Name HCL Vap Component flow rate 70 Kg h comp in air gas 6 v v presumed given by client by process cal Molecular weight of comp 36 5 Liquid Scrubbing media Properties Scrubbing media 20 NaOH Liquid flow rate L 77 kg h 0 0214 kg s Liquid Density L 1100 kg m3Conversion Liquid Viscosity L 0 0035000 Ns m23 5 Cp 0 00350000Ns m2 Packing factor Fp 21 m 1 Charac Packing Factor Cf 33 Ref Table 6 3 Characterstics of Random packings Conversion factor J 1 0 factor for adequate liquid distribution irrigation across the bed Sheet 2 of 10 Calculations TO CALCULATE COLUMN DIAMETER Since larger flow quantities are at the bottom for an absorber the diameter will be chosen to accommodate the bottom conditions To calculate Gas density Avg molecular weight 29 45 Kg Kmol If gas flow rate is given in kg hIf gas flow rate is given in m3 h Gas in 0 009432183 Kmol sGas in m3 s x 273x pr in atm x 1 kmol mass mol wt T in kelvin1 0 atm22 4 kmol s x T in kelvin x 1 0 atm x 22 4 273 pr In atm 1 0 Kmol s 0 234499 m3 s 0 Kg s mass mol wt x kmol Select vol flow rate and mass flow rate from above Selected mass flow rate 0 2777778 Kg s Selected vol Flow rate 0 234499 m3 s Selected molar flow rate 0 0094322 Kmol s Therefore gas density 1 1846 Kg m3 mass flow rate vol Flow rate To find L G and Tower c s area Assuming essentially complete absorbtion Component removed 0 0207 Kg s molar flow rate x comp x mol Wt Liquid leaving 0 0420 Kg s Inlet liquid flow rate comp Removed L G 0 5 0 00497 G L Using 0 00497as ordinate Refer fig 6 34 using a gas pressure drop of 147 1 N m2 m G 2 Cf L0 1 J 0 04 from graph G L G gc Therefore G 0 04 G L G gc 0 5 Cf L0 1 J 1 6665 Kg m2 s Tower c s area 0 1667 m2 c s area mass flow rate G Tower diameter 0 4607 m 460 7 mm 500 mm Sheet 3 of 10 Corresponding c s area 0 1963 m2 TO ESTIMATE POWER REQUIREMENT Efficiency of fan blower 60 assumed given To calculate pressure drop Pressure drop for irrigated 470 72 N m2 pressure drop per m packing x total ht of packing packing For dry packing O L Gas flow rate G 1 3095 Kg m2 s Gas inlet flow rate Component removed c s area O L Gas pressure 100854 28 N m2 subtracting pressure drop across packing Gas density G gas mol wt x 273 x gas o l pr 22 41m3 Kmol T in kelvin101330 1 1605 Kg m3 CD 96 7 Ref Table 6 3 Characterstics of Random packings Delta P CD G 2 ZG 142 89 N m2 Pressure drop for packing 613 61 N m2 irrigated packing dry packing Pressure drop for internals 25 mmWC packing supports and liquid distributors 245 17 N m2 Gas velocity 7 5 m s Inlet expansion outlet 1 5 x Velocity heads 1 5 x V2 2g contraction losses 42 19 N m Kg 49 97 N m2 divide by density Total pressure drop 908 75 N m2 packing internals losses Fan power output pressure drop N m2 x gas in component removed Kg s O L gas density Kg m3 201 35 N m s 0 20 kW Power for fan motor 0 34 kW fan power output motor efficiency 0 45 hp Sheet 4 of 10 COLUMN DIAMETER HYDRAULIC CHECK Liq Vap Flow factor FLV L V x V L 0 0025 Design for an initial pressure drop of 15mm H2O m packing From K4 v s FLV K4 0 85 K4 at flooding 6 50 Trial flooding K4 K4 at flooding x 100 36 1620 Gas mass flow rate Vm K4 V L V 13 1 Fp L L 0 1 3 7763 kg m2 s Trial column c s area V Vm Trial As 0 0736 m2 Trial column dia D 0 3060 mD 4 pi x Trial As Round off D to nearest standard size Therefore D 0 500 m Column C S area As 0 1963 m2As pi 4 x D2 flooding 13 5472 flooding Trial flooding x Trial As As Conclusion Generally packed towers are designed for 50 85 flooding If flooding is to be reduced i Select larger packing size and repeat the above steps OR ii Increase the column diameter and repeat the above steps 1 2 Sheet 5 of 10 HETP PREDICTION Norton s Correlation ln HETP n 0 187 ln 0 213 ln Applicable when liquid phase surface tension 4 dyne cm 0 08 cP 0 83 cP Conversion Input Data0 018 N m 18dyne cm Liquid phase Surface Tension 20 dyne cmNorton s Correlation Applicable Liquid Viscosity 3 5 cPNorton s Correlation NOT applicable n 1 13080 Calculation ln HETP 0 8374366 HETP 2 3104368 ft 0 7042211 m For separations less than 15 theoritical stages a 20 design safety factor can be applied Considering 20 safety factor HETP 0 8450653 m For separations requiring 15 to 25 theoritical stages a 15 design