Make a preliminary design for a separator to separate a mixture of steam and water; flow-rates: steam 2000 kg/h, water 1000 kg/h; operating pressure 4 bar.
Question 10.5: Make a preliminary design for a separator to separate a mixt...
From steam tables, at 4 bar: saturation temperature 143.6^{\circ} C, liquid density 926.4 kg / m ^{3}, vapour density 2.16 kg / m ^{3}.
u_{t}=0.07[(926.4-2.16) / 2.16]^{\frac{1}{2}}=1.45 m / s (10.10)
As the separation of condensate from steam is unlikely to be critical, a demister pad will not be specified.
\text { So, } u_{t}=0.15 \times 1.45=0.218 m / s
\text { Vapour volumetric flow-rate }=\frac{2000}{3600 \times 2.16}=0.257 m ^{3} / s
D_{v}=\sqrt{[(4 \times 0.257) /(\pi \times 0.218)]}=1.23 m \text {, round to } 1.25 m (4 ft ) \text {. } (10.11)
\text { Liquid volumetric flow-rate }=\frac{1000}{3600 \times 926.14}=3.0 \times 10^{-4} m ^{3} / s
Allow a minimum of 10 minutes hold-up.
\text { Volume held in vessel }=3.0 \times 10^{-4} \times(10 \times 60)=0.18 m ^{3}
\text { Liquid depth required, } h_{v}=\frac{\text { volume held-up }}{\text { vessel cross-sectional area }} =\frac{0.18}{\left(\pi \times 1.25^{2} / 4\right)}=0.15 m
Increase to 0.3 m to allow space for positioning the level controller.
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