Centrifuge Blanketing System

The dangers of flash fires and explosions is inherent is many plant operations. Specifically, the combination of volatile solvents and dusts in process vessels, such as a high-speed Industrial Centrifuge, where highly flammable conditions can be created. Unless proper safety measures are undertaken, this situation can potentially lead to catastrophic fires and explosions.
The potential hazards involved in the use of Industrial Centrifuges for the separation of solids from flammable liquids are gaining even greater awareness and importance because of a number of serious incidents involving personal injury or regrettably death. Methods of monitoring and avoiding such hazards are important to all those involved, not just the production operator and safety manager.
Inertizing systems are not new. There have been traditionally two approaches.

Application

  • There is an extensive range of Centrifuge types and sizes. The most common type is the top or bottom discharge filtration batch centrifuge. Other types include the Continuous Decanter Centrifuge, the Disc Stack etc.

  • The types of industries using Industrial Centrifuges are similarly diverse. These include the chemical, pharmaceutical, petro-chemical and food industries. Every year a number of explosions involving Centrifuges are reported. Each time the accident enquiry pinpoints human error, equipment failure or bad engineering design as the major causes.

A typical process cycle of a batch type Centrifuge:

  • Centrifuge sweeping or purging with nitrogen gas, usually Nitrogen.

  • Feed slurry is introduced to the Centrifuge, i.e. the separation stage.

  • Again purge the centrifuge with the inert gas to remove the oxygen level.

  • Close Purging operation & start blanketing throughout spinning.

  • After final spinning, most of the liquid has been removed from the cake.

  • Final remaining solids are discharged from the basket or bowl.

  • During all these operations the Centrifuge must be inert either by purging or by blanketing with inert gas.

  • The principle behind inertizing is that if one can keep the oxygen level below the minimum oxygen level for combustion (MOC) i.e. 3 – 6% then there is zero probability for an explosion.

The System

In pharmaceutical industry three types of Inertization systems are widely used based on application / criticality / suitability and commercial aspect
Manual Centrifuge Blanketing System
Semi-Automated / Timer Based System
Fully Automated / On-Line Oxygen monitoring system

Brief on the Manual System

Manual Centrifuge Blanketing System
brief-on-the-manual-system

Manual Centrifuge Blanketing System is one of the most preferred system in pharma industry because of the following advantages :

  • User-friendly and easy to understand & operate.

  • Operator has to operate only two isolation valves.

  • Except Nitrogen no other utility required.

  • No special tools & tackles / expertise are required.

  • Minimum corrections to upgrade to Semi or Fully Automated.