• Author / Uploaded
• chem_ta

Citation preview

Rotary Valve Estimation of gas leakage through the rotary valve, the types of leakage consist of; 1. Carry-Over Leakage 2. Clearance Leakage 3. Labyrinth Leakage (Seal Leakage) The total flow of leakage is sum of carry-over leakage and clearance leakage, but for labyrinth leakage was predicted around zero according to assumes that it was new condition.

Qtotal =

P1 [Q1 + Q 2] P2

Where P1 = Fluid pressure for transportation (Pa) P2 = Silo Pressure (Pa) Q1 = Carry Over leakage (m3/min) Q2 = Clearance Leakage (m3/min)

Carry-Over Leakage (m3/min) Q1 =

3.14 D 2 LN 4

Where D = Diameter of rotary valve (m) L = Length of rotary valve (m) N = Revolution (rpm)

Clearance Leakage (m3/min) Q2 = 36kA

2ΔP

ρ

Where k = compression faction of fluid A = Gap between rotor and casing ΔP = Difference pressure between transport fluid and hopper/silo pressure (Pa) ρ = Density of transport fluid (kg/m3)

Mass flow capacity of rotary valve

Where

m s = αρ b vnN

0.12027 xMWxP( kPa ) And ρ= T ( o C + 273)

k=

P ⎞ 1 ⎛ ⎜⎜ 4.35 − 1 ⎟⎟ − 0.2 3.5 ⎝ P2 ⎠

Normally, Rate of mass flow through the rotary valve will depend on particle characteristic, roughness, size and revolution of rotary valve. Estimated formula as following

Where Ms = Mass flow rate (kg/min) α = Filling factor

ρb

= Bulk density (kg/m3)

v = Volume of one-channel of rotor n = Number of channel N = Revolution (rpm)