Engg. Calculation.xlsx

Separation efficiency required is to remove water droplets above the size of 10 microns. Fuel gas properties can be approximately taken as properties of ethane. Source: EnggCyclopedia Sr. No.

Step 1

Step 2

Step 3

Step 4

Paramter

Value

Unit

Flow rate of water Entrained Flow of fuel gas

18 100

m3/hr m3/hr

Operating temperature of separator Operating pressure of separator

25 0C 0.2 barg (near atmospheric)

Properties Water density at 25 0C Water viscosity at 25 0C For fuel gas properties, Molecular weight of ethane Fuel gas density at 25 0C Fuel gas viscosity at 25 0C

994.72 0.9

kg/m3 cP

30 1.45 0.0069

gm/gmole kg/m3 cP

Vt

0.01

m/s

Nre

0.87

Assumption H/D

3.5

Terminal velocity of gas phase Diameter of vessel L

0.01 2.43 8.49

Gas Bubble terminal velocity

m/s m m

he size of 10 microns.

Sr. No.

Step 1

Step 2

Paramter

Value

Unit

Flow rate of water Entrained Flow of fuel gas

18 100

m3/hr m3/hr

Operating temperature of separator Operating pressure of separator

25 0.2

0C barg (near atmospheric)

994.72 0.9

kg/m3 cP

30 1.45 0.0069

gm/gmole kg/m3 cP

Properties Water density at 25 0C Water viscosity at 25 0C For fuel gas properties, Molecular weight of ethane Fuel gas density at 25 0C Fuel gas viscosity at 25 0C

maximum allowable gas velocity, VGmax, which prevents entrainment of liquid V = (k) [ (dL - dV) / dV ]0.5 where:

V = maximum allowable vapor velocity, m/sec dL = liquid density, kg/m3 dV = vapor density, kg/m3 k = 0.107 m/s (when the drum includes a de-entraining mesh pad) VGmax

Step 3

2.80

m/s

0.01 0.11 112.38

m2 m mm

Diameter calculation

Area, A D

The drum should have a vapor outlet at the top, liquid outlet at the bottom, and feed inlet at s At the vapor outlet, provide a de-entraining mesh pad within the drum such that the vapor mu Depending upon how much liquid flow you expect, the liquid outlet line should probably have As for the mechanical design of the drum (i.e., materials of construction, wall thickness, corros

Recommended values of k

The GPSA Engineering Data Book[7] recommends the following k values for vertical drums with horizontal mesh pads (at the denoted operating pressures): At a gauge pressure of 0 bar: 0.107 m/s At a gauge pressure of 7 bar: 0.107 m/s At a gauge pressure of 21 bar: 0.101 m/s At a gauge pressure of 42 bar: 0.092 m/s At a gauge pressure of 63 bar: 0.083 m/s At a gauge pressure of 105 bar: 0.065 m/s GPSA 1. k = Notes: 0.107 at a gauge pressure of 7 bar. Subtract 0.003 for every 7 bar above a gauge pressure of 7 bar. 2. For glycol or amine solutions, multiply above k values by 0.6 - 0.8 3. Typically use one-half of the above k values for approximate sizing of vertical separators without mesh pads 4. For compressor suction scrubbers and expander inlet separators, multiply k by 0.7 - 0.8

he bottom, and feed inlet at somewhat above the half-full level. drum such that the vapor must pass through that mesh before it can leave the drum. let line should probably have a level control valve. ruction, wall thickness, corrosion allowance, etc.), use the same methodology as for any pressure vessel.