Download Process Design of Spray Chamber or Spray Tower Type Absorber PDF

TitleProcess Design of Spray Chamber or Spray Tower Type Absorber
File Size23.0 MB
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Process design of spray chamber or spray tower type

Absorber
Definition: spray absorber is a mechanical device used for removing so2 from boiler
flue gases that is exhausted from a boiler.

Basic information:
>it have either circular or rectangular cross section & there is no packing in the spray

absorber.

>it is divided in two types: 1.verticle 2.horizontal

>liquid phase residence time in spray absorber is very low as 1 to 10 second; hence the

chemical reagent can be added in liquid phase to get higher rate of absorption.

Process design of vertical & horizontal spray tower:
>in vertical spray tower gas stream is flowing vertically upward & liquid is sprayed

downward in various section within the tower while in horizontal spray tower gas

stream is flowing horizontally through it and liquid is sprayed vertically downward

perpendicular to the direction of gas flow

Process design steps for vertical and horizontal spray tower are as follows:

Step-1
Determination of tower diameter or duct area
>for vertical spray tower: max. Permissible gas velocity is 2.3 m/S but actual velocity is

less than 2.3 m/s, while actual velocity is less than 7 m/s for horizontal spray tower. To

avoid excessive entrainment of liquid droplets in the exits gas. Diameter of vertical &

horizontal spray tower is calculated by following equitation.



D = qv*4

ug*π

Where, D= tower diameter, m

qv= volumetric flow rate of gas , m3/s

ug= gas velocity through tower , m/s

=for vertical spray tower < 2.3 m/s

= for horizontal spray tower <7 m/s

Step-2
Determination of no. Of gas phase transfer unit required for

separation by following equitation.


NG = y1– y2 for vertical spray tower

y2

NG = ln y1 for horizontal spray tower

y2

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