填料塔设计Excel

Column Tag No.:

HCL Scrubber Job No.:4506A Client :JOL

Project :SR - Plant -4, 5Input Data

Stream

:

HCL Vap.

Packing type =Intallox Saddles Packing size =25mm Packing MOC

=PP Gas pr. Drop / m bed =15mmWC / m packing height =147.1(N/m 2

)/m

Total packing height

= 3.2m (including all packed beds)

Gas / Vapour Properties Gas / Air flow rate =

OR

0m 3

/h == 0m 3/s

Gas pressure at entry = 1.0000atm

Gas temperature at entry =30.00o

C =303.00o

K

Gas / Air mol weight

=

29

Component to be scrubbed Component Name =HCL Vap

Component flow rate =70Kg/h % comp. in air/gas =6% (v/v)Molecular weight of comp.=

36.5

3

Conversion :

Liquid Viscosity, µL =0.0035000Ns/m 2 3.5C p =

Ns/m 2

Packing factor, F p

=

21m -1

Charac. Packing Factor,C f =33 Ref. Table 6.3, Characterstics of Random packings

Conversion factor, J = 1.0factor for adequate liquid distribution & irrigation across the bed

SCRUBBER DESIGN (PACKED COLUMN)

0.00350000

Calculations

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 =29.45Kg / Kmol

Select vol. flow rate and mass flow rate from above,Selected mass flow rate =0.277778Kg/s

Selected vol. Flow rate =0.234499m 3

/s Selected molar flow rate =0.009432Kmol/s Therefore, gas density

=

1.1846Kg/m 3

(mass flow rate / vol. Flow rate)

To find L', G' and Tower c/s area

Assuming essentially complete absorbtion, Component removed =0.0207Kg/s (molar flow rate x % comp. x mol. Wt.)

Liquid leaving =0.0420Kg/s (Inlet liquid flow rate + comp. Removed)

0.5

=0.00497

Using

0.00497

as ordinate, Refer fig.6.34 using a gas pressure drop of 147.1(N/m 2

)/m

G' 2 C f µL 0.1 J =

0.04 (from graph)

G ) g c Therefore, G'

=

0.5

=

1.6665Kg / m 2

.s Tower c/s area =0.1667m

2

( c/s area = mass flow rate / G' )Tower diameter

=0.4607m =

460.7mm

=500mm Corresponding c/s area

=

0.1963m 2

TO CALCULATE COLUMN DIAMETER

Efficiency of fan / blower

=

60%

To calculate pressure drop Pressure drop for irrigated =470.72N/m 2

(pressure drop per m packing x total ht. of packing)

packing

For dry packing,

O/L Gas flow rate, G'=

2.s (Gas inlet flow rate - Component removed) / c/s area

O/L Gas pressure

=2

(subtracting pressure drop across packing)= gas mol wt. x 273 x gas o/l pr. 22.41m3/Kmol T in kelvin 101330=C D =

96.7 Ref. Table 6.3, Characterstics of Random packings

Delta P = Z

=

2

Pressure drop for packing =613.61N/m 2(irrigated packing + dry packing)Pressure drop for internals =25mmWC

(packing supports and liquid distributors)

=245.17N/m

2

Gas velocity

=7.5m/s

Inlet expansion & outlet = 1.5 x Velocity heads = 1.5 x (V 2

/ 2g)contraction losses

=42.19N m / Kg

=49.97N/m 2

(divide by density)

Total pressure drop =

908.75N/m

2

(packing + internals + losses)

Fan power output

=pressure drop,N/m 2 x (gas in - component removed) Kg/s

O/L gas density, Kg/m 3

=201.35N .m / s =0.20kW Power for fan motor

=0.34kW (fan power output / motor efficiency)

=

0.45hp

TO ESTIMATE POWER REQUIREMENT

Liq.-Vap. Flow factor, F LV

=

=Design for an initial pressure drop of

15

mm H2O /m packing

From K 4

v/s F LV ,K 4

=0.85K 4 at flooding =

6.50

Trial % flooding

==Gas mass flow rate, V m

==

3.7763kg/m 2

.s Trial column c/s area

=V / V m (Trial A s )

=

0.0736m 2Trial column dia., D =

0.3060m

D = (4/pi) x Trial A s

Round off 'D' to nearest standard size Therefore, D =0.500m

Column C/S area, A s

=0.1963m

2

A s =(pi/4) x D

2

% flooding =13.5472

% flooding = Trial % flooding x (Trial A s / A s )

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.

COLUMN DIAMETER / HYDRAULIC CHECK

(1/2)

Input Data 0.018 N/m =dyne/cm Liquid-phase Surface Tension, =20dyne/cm Liquid Viscosity = 3.5cP n

=

1.13080

Calculation ln HETP =0.837437HETP

=

=

For separations, less than 15 theoritical stages, a 20% design safety factor can be applied.Considering 20% safety factor, HETP =0.845065m

For separations, requiring 15 to 25 theoritical stages, a 15% design safety factor can be applied.HETP =HETP PREDICTION

Norton's Correlation Applicable Norton's Correlation NOT applicable

18