How to Handle Vacuum Crystallizer / Cooling Crystallizer, those are commission this plant, the following subjects to be checked, while operating the plant
After commission the Vacuum Crystallizer before going to start the system, Ensure the Steps / Checklist
1. Raise the vacuum first using by cooling tower after reaching around 100- 200 mmHg. Inject the steam into Primary Condenser then Secondary condenser wait until vacuum builds / increase up to 400 mmHg
2. Then inject the steam to the booster, which fitted over the Crystallizer’s main Vessel, the vacuum further builds, once it reach around 700mmHg.
> Steam pressure must be maintained uniformly, if reduce the pressure the vacuum gets down.
3. Inject the product Feed to the vessel slowly,
> Feed liquid Temperature is very sensitive part maintain around less then 30 Deg C, if feed temperature increases the steam consumption also increases, finally cooling tower will get additional load.
4. Product Feed’s Specific Gravity to be maintained uniformly example Na2SO4 Plant 1.25-1.28 @30 Deg C is better.
5. Check the Temperature feed side and outlet(Drain) side of the vessel, outlet side temperature has always lesser compare with feed side.
To Increase the efficiency of Vacuum Crystallizer Plant,
Insulate the Crystallizer Main Vessel using with Cold Insulation,
- Suggested thickness around 100 mm would better.
- Take Cooling tower capacity size at least 1.2 higher than normal calculation arrival.