酸雾塔塔计算表scrubber_design

(molar flow rate x % comp. x mol. Wt.) (Inlet liquid flow rate + comp. Removed)
=
0.00497
0.00497
as ordinate, =
Refer fig.6.34 using a gas pressure drop of
147.1
(N/m )/m
2
G' 2 Cf µL0.1 J
G( L
0.04 (from graph)
--
G)
gc = 0.04
G( L
Therefore, G'
-0.1
G)
gc
0.5
Cf µL = Tower c/s area Tower diameter = = = =
J
1.6665 Kg / m2.s 0.1667 m2 0.4607 m 500 mm 0.1963 m2 ( c/s area = mass flow rate / G' ) = 460.7 mm
To find L', G' and Tower c/s area Assuming essentially complete absorbtion, Component removed = 0.0207 Kg/s Liquid leaving = 0.0420 Kg/s L' G' Using
0.5 G L
Conversion : 3.5 Cp = 0.00350000 Ns/m2
Charac. Packing Factor,Cf = Conversion factor, J =
33 Ref. Table 6.3, Characterstics of Random packings 1.0 factor for adequate liquid distribution & irrigation across the bed
Sheet 1 of 5
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 = If gas flow rate is given in kg/h Gas in = 0.009432183 Kmol/s kmol = mass / mol wt = (kmol/s) x T in kelvin x 1.0 atm x 22.4 273 pr. In atm 1 3 = 0.234499 m /s
Corresponding c/s area
Sheet 2 of 5
TO ESTIMATE POWER REQUIREMENT Efficiency of fan / blower = 60 % assumed / given
To calculate pressure drop Pressure drop for irrigated = packing For dry packing, O/L Gas flow rate, G' O/L Gas pressure Gas density, G 470.72 N/m2 (pressure drop per m packing x total ht. of packing)
G
CD Delta P Z
Ref. Table 6.3, Characterstics of Random packings
142.89 N/m2 613.61 N/m2 25 mmWC 245.17 N/m2 (irrigated packing + dry packing) (packing supports and liquid distributors)
: : : : :
HCL Scrubber 4506A JOL SR - Plant -4, 5 HCL Vap.
Input Data Packing type Packing size Packing MOC Gas pr. Drop / m bed Total packing height
=
147.1 (N/m )/m
OR =
0 m /h 0 m3/s
3
=
303.00 oK
Component to be scrubbed Component Name = Component flow rate = % comp. in air/gas = Molecular weight of comp. =
HCL Vap 70 Kg/h 6 % (v/v) 36.5
V) 0.1
(1/2)
3.7763 kg/m .s V / Vm 0.0736 m2 0.3060 m D = (4/pi) x Trial As
Round off 'D' to nearest standard size Therefore, D = 0.500 m
Column C/S area, As
(presumed) / (given by client) / (by process cal.)
Liquid / Scrubbing media Properties Scrubbing media = 20% NaOH Liquid flow rate, L = 77 kg/h = 0.0214 kg/s Liquid Density, L = 1100 kg/m3 Liquid Viscosity, µL Packing factor, Fp = 0.0035000 Ns/m2 = 21 m-1
Pressure drop for packing = Pressure drop for internals = = Gas velocity Inlet expansion & outlet contraction losses
= 7.5 m/s = 1.5 x Velocity heads = 42.19 N m / Kg = 49.97 N/m2 = 908.75 N/m2
15
mm H2O /m packing
= ( (K4 / K4 at flooding) = 36.1620 = K4 .
V( L
) x 100
Gas mass flow rate, Vm
-L) 2
13.1 Fp (µL / = Trial column c/s area (Trial As) = = Trial column dia., D =
Calculation ln HETP HETP = = = 0.837437 2.310437 ft 0.704221 m
=
0.1963 m2
As = (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.
=
1.5 x (V2 / 2g) (divide by density)
Total pressure drop Fan power output
(packing + internals + losses)
= pressure drop,N/m 2 x (gas in - component removed) Kg/s O/L gas density, Kg/m 3 = 201.35 N .m / s = 0.20 kW = = 0.34 kW 0.45 hp (fan power output / motor efficiency)
SCRUBBER DESIGN (PACKED COLUMN)
Prepared by : Checked by : Date :
Column Tag No. Job No. Client Project Stream = Intallox Saddles = 25 mm = PP = 15 mmWC / m packing height = 3.2 m (including all packed beds)
2
Gas / Vapour Properties Gas / Air flow rate = = Gas pressure at entry Gas temperature at entry Gas / Air mol weight = = =
1000 kg/h 0.2778 kg/s 1.0000 atm 30.00 oC 29
Power for fan motor
Sheet 3 of 5
COLUMN DIAMETER / HYDRAULIC CHECK Liq.-Vap. Flow factor, FLV = (L / V) x ( = 0.0025
V
/
L)
Design for an initial pressure drop of From K4 v/s FLV, K4 K4 at flooding Trial % flooding = = 0.85 6.50
29.45 Kg / Kmol If gas flow rate is given in m3/h Gas in = (m3/s) x 273 x pr. in atm x T in kelvin 1.0 atm 1 22.4
= =
0 Km来自百度文库l/s 0 Kg/s mass = mol wt x kmol
Select vol. flow rate and mass flow rate from above, Selected mass flow rate = 0.277778 Kg/s Selected vol. Flow rate = 0.234499 m3/s Selected molar flow rate = 0.009432 Kmol/s Therefore, gas density = 1.1846 Kg/m3 (mass flow rate / vol. Flow rate)
Sheet 4 of 5
HETP PREDICTION Norton's Correlation : ln HETP = n - 0.187 ln + 0.213 ln µ Applicable when, liquid phase surface tension > 4 dyne/cm & < 36 dyne/cm liquid viscosity > 0.08 cP & < 0.83 cP Conversion : Input Data 0.018 N/m = 18 dyne/cm Liquid-phase Surface Tension, = 20 dyne/cm Norton's Correlation Applicable Liquid Viscosity n = = 3.5 cP 1.13080 Norton's Correlation NOT applicable
1.3095 Kg / m2.s (Gas inlet flow rate - Component removed) / c/s area 2 100854.3 N/m (subtracting pressure drop across packing) gas mol wt. x 273 x gas o/l pr. 22.41m3/Kmol T in kelvin 101330 = 1.1605 Kg/m3 = = = = = CD = 96.7 G' 2