Sterilizer stations development over the past 30 years

 First generation palm oil mill

Early 70s

 Capacity: 30-60 tons / hr

Machineries :

  • 2 tons cages
  • Horizontal Sterilizer
  • 9 tons Screw Presses
  • Overhead crane
 Second generation palm oil mill

Early 80’s to 90’s

 Capacity: 30 -60 tons / hr

Machineries :

  • 5 tons cages
  • Horizontal sterilizer
  • 10-15 tons Screw Presses
  • Overhead crane
 Third generation palm oil mill

Early 90’s & beyond

 Capacity: 90-120 tons/ hr

Machineries :

  • 7-10tons cages
  • Horizontal Sterilizer
  • 20 tons Screw Press
  • FFB Tippler / Conveyor / Indexer
VS 3D Diagram

VS 3D Diagram


  • FFB dropping from height causes mechanical damages on to the internal parts
  • FFB knocking and bruising cause high oil loss and increases FFA
  • Arching problem affects discharging of SFB
  • Uneven steam distribution affects sterilization
  • Prolonged sterilization cycle time
  • Higher steam consumption
  • 10 ton FFB per charge


  • Vertical Sterilizer (latest version) is designed to create arching effect during sterilization (under pressure)
  • This will lessen the compactness of the sterilized fruit inside the VS
  • Once the discharge door is opened, the SFB bridging (arching) will collapse naturally
  • No more downtime due to bridging during SFB (sterilized fruit bunch) discharge

Horizontal Sterilizer and Cages System

  • FFB are loaded into cages and charged into the sterilizer for cooking
  • Area taken up by horizontal sterilizer is dependent on the size of cages
  • Uses a lot of cages –ranges from 40 units @ USD2800 per cage
  • Uses 5 railway tracks for a 45tones/hr mill
  • Modern Mill uses tippler incl. conveyor, transfer carriage, winch, indexer, etc
  • Sterilization Station is very long to accommodate length of sterilizers and large marshalling yard is required
  • Oil losses resulting from spilled fruitlesduring loading to cage, transfer to sterilizer and out to thresher, oil dripping from cage and sterilizer condensate.
  • Triple or double sterilizing cycle is required for proper cooking.-Condensate oil cannot be recovered due to iron pick-up.-Reduced cages lifespan
  • Savings of labor as less manpower is required to operate the mill
  • High maintenance cost for railway, tracks, boogie wheels for cages, overhead crane/ tippler, winch / capstan, prime movers, marshalling yards upkeep.
  • Pit design is required


  • FFB are loaded directly into the sterilizer, NO cages are used
  • Area taken up by vertical sterilizer is significantly smaller
  • FFB feeding by conveyor
  • Conveyor arrangement is used
  • Simple FFB handling
  • Smaller sterilization station with slightly higher building
  • Direct filling of FFB and discharge to stripper. No spillage & oil drip. Sterilizer condensate oil is recovered to system.
  • FFB cooking time is much shorter achieved due to better steam penetration
  • Less workers are needed because automation features through PLC / SCADA
  • Minimal maintenance cost
  • Mass concrete in single level
VS System Diagram

VS System Diagram


Mill layout at sterilizer station Compact design, pit-less Bigger area (4 times) with pits
Labor requirement/shift(Reception-thresher) 3 workers 6 to 12 workers
Steam consumption 130-160kgs/ton FFB 270 -350kgs/ton FFB
Oil recovery potential HighCondensate oil fully recoverable with minimum loss LowCondensate oil not encouraged to be recovered (poor quality)
Downtime and maintenance Relatively low maintenance and breakdown (lesser machinery) HigherMaintenance on cages,rail track, tipper/crane,cantilever, transfer car, winch/capstan,pit,sterilizer liner…….
House-keeping Better housekeeping.(closed system with minimum spillages, smaller floor area) Difficult housekeeping-Oily and slippery, larger floor area, more machinery & pits
Work hazard SafeLess moving machines HigherMore moving machines & pits
Operation Simple and safe operation (semi automatic system) Multiple machinery & complicated operations. Mainly manual works


  • Based on the results of the mill operating on VS, the cost of operation and extraction efficiency have improved significantly
  • VS system is a one-way traffic arrangement that uses cage-less & pit-less design
  • VS system is more energy efficient (Steam and electrical power savings)
  • VS system relatively improves food safety compares to conventional system (horizontal sterilizer)
  • VS system improves operational safety and environment

Sumber : CHD Marketing Presentation