improving the efficiency of your ozone system...ozone gas (need 64 scfh) find: motive force (gpm)...
TRANSCRIPT
Improving the Efficiency of Your
Ozone System
By Alison Trollier
May 5, 2010
Agenda•Ozone – Review•Contacting & Mass Transfer•Evolution of Ozone Contacting•Venturi Injector Sizing•Maximizing Transfer Efficiency•Benefits of Transfer Efficiency
•Strongest disinfectant•Improves water clarity•No hazardous chemical handling•No disinfection by-products•No added TDS•Rapid decay to Oxygen
Ozone
Introduction Method is Key to System Efficiency
Ozone System EfficiencyEffective ozone disinfection requires CT:
•Transfer efficiency
•Good mixing
•Adequate Contact time
•Minimal short circuiting in contactor
Contacting
Contact Time
Contacting – what does this word mean?
•Driving the gas into solution•Not just bubbles-in, bubbles-out
•Ozone as a gas – does not disinfect
•Gas not dissolved is wasted
•Gas-to-liquid transfer (mass transfer)
•Happens only at the gas-liquid interfacial exposure
Bubbles•Def: a globule of one substance encased in another, usually gas in a liquid
Gas-liquid interface -where all transfer occurs
Gas inside the bubble-this gas is wasted unless the bubble is sheared to renew the gas-liquid interface
Gas to Liquid TransferTransfer happens only at the gas-liquid interface
(surface area of bubbles)
•Micro-bubbles – Good•High surface area per volume
•Large Bubbles – Bad •Low surface area per volume
Mass Transfer Principles
Four Factors affect mass transfer efficiency:
•Ozone Gas Concentration
•Gas-to-liquid Volume Ratio
•Mixing Pressure – Henry’s Law
•Mixing Velocity – Renewal of gas/liquid interface
Venturi Injectors
Demonstrates the Bernoulli Principle –
“Where there is higher velocity, there is lower pressure…”
Venturi InjectorsWith booster pump With Pressure Reducer
Outlet/Downstream Pressure (PSI)Motive Force (GPM)Inlet Pressure (PSI)
Ozone Gas (SCFH)
Injector Performance Tables
Outlet Pressure (Must be >20 PSI)
MotiveForce?& Inlet Pressure? Ozone Gas
(NEED 64 SCFH)
Find: Motive Force (GPM)Required Inlet Pressure (PSI)Injector Model Number
54.1 GPM required, at 45 PSI to get 73.7 SCFH of gas suction
Outlet/Downstream Pressure must be >20 PSI to overcomeline pressure
Use Injector Model 1584
Evolution of Ozone Contacting
Fine Bubble Diffusion
1980’s
Lower Gas/Liquid RatioHigher Mixing VelocityHigher Mixing Pressure
Venturi Injector with Large Contact/Degas Vessel
Evolution of Ozone Contacting
PressurizedContacting & Degassing
1995
Higher Mixing VelocityHigher Mixing PressureEntrained Gas Removal
Venturi Injector with Large Contact/Degas Vessel
Evolution of Ozone Contacting
PressurizedContacting & Degassing
Secondary Mixing
Higher mixing velocityHigher mixing pressure
Evolution of Ozone Contacting
Maximize Your Transfer Efficiency
• Interfacial exposure renewal•Re-shear bubbles
•High Mixing Velocity
•High Ozone Gas Concentration
•High Mixing Pressure
•Low Gas-to-liquid Volume Ratio
Maximize Transfer EfficiencyOzone TE Vs Pressure
(TE Vs G/L)
0.010.0
20.030.0
40.050.0
60.070.0
80.090.0
100.0
1 10 20 30 40
Injector/Nozzle Outlet PSIG
% T
rans
fer E
ff
0.06 0.10 0.14
G/L = 0.06
G/L = 0.10
G/L = 0.14
G/L = ft3 gas ft3 water
Benefits of High MTE•More efficient use of ozone
•Smaller gen or extra capacity
•Less pump horsepower
Benefits of New Technology•Smaller footprint
•No need to re-pressurize
•Safety
•Ease of maintenance
