Continuous Solid-Liquid Separation

Solids are continuously separated from the liquid phase by the application of centrifugal force ranging up to 3000 times the force of gravity, efficiently and economically. A characteristic feature of the Pennwalt Decanter Centrifuge is the cylindro-conical bowl containing within a helical/quasi-axial screw conveyor of matching profile that rotates in the same direction but at a slightly slower speed with respect to the bowl.

Extremely flexible Separation tool

• Handling a wide range of solid particle sizes from 5.0 mm to a few microns
• Handling slurries with insoluble solids content from as low as 0.5%w/v to as high as 55% w/v

Wide ranging, process specific applications of Pennwalt Decanter Centrifuge encompass:

• Clarification of liquids.
• Dewatering or deliquoring of solids
• Thickening or concentration of solids
• Classification of solids suspended in liquid

For a detailed list of applications where the Pennwalt Decanter Centrifuge has been successfully used click here

Economical Operation

Pennwalt Decanter Centrifuge, has polymiser features, wherein the feed zone & conveyor flights are modified to reduce the floc breakage and minimise conveyor turbulence in the pool. These features result in considerably reduced dose of polymeric flocculants. In addtion there is economy of space, power and labour required in the operation of the Pennwalt Decanter Centrifuge.

Stainless Steel Construction designed to resist corrosion

Carbon Steel corrodes, leading to unbalance, high maintenance costs, long downtimes. Therefore the principle elements and stressed rotating components of Pennwalt Decanter Centrifuge are machined from quality centrifugally cast Stainless Steel.

Designed to resist abrasion

Sintered Tungsten Carbide Tiles positioned on the flights of the Pennwalt Decanter Centrifuge scroll (conveyor) outlast conventional hard surfacing systems many times over in any environment.

BD Feature

This makes slimy and gelatinous sludges SCROLLABLE. The BD feature allows the Super-D-Canter to operate at Ultra-Deep pond settings that compacts the solids and creates a hydrodynamic buoyancy that assists the scrolling and the discharge of slimy sludge. Solid content are typically 1/2% - 2% in the feed slurry and 6%-12% in the slimy cake.

3-Phase:

This is a Pennwalt Decanter Centrifuge which is designed to give three separate product phases such as water, Oil, and Cake Solids. Applications encompass Olive Oil, Fish Oil, Fish Blood-Water, Slop Oil etc. Often, one or both liquid phases need to be further polished on the high-Tubular Bowl Supercentrifuge.

Sterile Features

For Pharmaceutical, Biotechnology and Food Industries, the Pennwalt Decanter Centrifuge can be provided with Sterilisation-in-place (SIP) and Clean-in-Place (CIP) features.

Four crucial factors govern the separational performance of Pennwalt Decanter centrifuges.

• Centrifugal force required to sediment the solids.
• Appropriate setting of the pool depth to achieve the required centrate liquid clarity.
• Control of differential speed between the bowl and scroll, to convey the solids and obtain appropriately low cake moistures.
• Hydrodynamic design of the conveyor to minimise turbulence.

In specifying a Decanter centrifuge, for a particular application, Pennwalt considers other design features such as :

• The pitch of the conveyor flights
• Number of Leads of the Conveyor
• Special Rinse or Floc Feature
  
• Feed zone design
  
• Beach angle
• Beach Surface Profile
  
• Bowl surface Profile
• Torque Sensing and Overload
• Back-Drive or Eddy Current Brake for control of Differential Speed
• Casing Enclosure design
  
• Abrasion Protection with Tungsten Carbide Tiles or Stellite Hard Surfacing of the Conveyor
  
• Material of construction
  
• Sedimentation enhancing features
  
• Safety Featured casing and guards

The Correct combination of such features ensures the desired separational performance for a given application at minimum cost. Operation at High 'G' force is an inherent design feature of the Pennwalt Super-D-Canter and provides flexibility to the user. The centrifuge can be operated at an optimum speed to suit the particular application.The Pennwalt Decanter can be operated at low, intermediate or high speed without the constraints of mechanical design, which can be optimised and tailored to suit each application.

1) Stressed rotating components are precision machined from centrifugally cast stainless steel.
2) High strength, high capacity epicyclic gearbox is designed exclusively for Pennwalt Decanter Centrifuge.
3) 360 degree solids discharge giving unrestricted solids exit coupled with high capacity with Full abrasion protection using sintered tungsten carbide shields.
4) Gearbox overload protection either by clutch or torque arm which can be easily reset without the need for shear pins.

The flexibility of Pennwalt Decanter Centrifuge design has proved to be effective in evolving solutions to a wide range of solid-liquid separations in the Chemical Process Industry.

However, the ideal methodology of evolving authentically tailored optional solutions to specific Solids-Liquid separational problems is to carry out trials with representative process slurries on geometrically similar pilot scale test models of the Pennwalt Decanter Centrifuge.

Trials can be carried out primarily on geometrically similar pilot scale test Pennwalt Decanter Centrifuges at Pennwalt Ltd’s World Class Research & Development Centre, which is well equipped with geometrically similar pilot scale Pennwalt Decanter Centrifuge Models P600, P660 and P1500, 24” Vibroscreen and Models AS-12/AS-16 high –G tubular Bowl Super Centrifuge up to a gravitational acceleration comparable with its industrial models.  Pennwalt is also equipped with laboratory testing facilities for preliminary testing and evaluation of the products emerging from the separation equipment. Thus the feed material can be assessed in accordance with its separability and settleability for appropriate selection of pretreatment and the separations equipment required to match customers performance duly specification.

Subsequent to the pilot scale evaluatory trials at Pennwalt, further detailed assessment trials can also be carried at customer site by Pennwalt Process Engineers and Technicians with either the pilot scale or industrial scale models to confirm the expected performance with variations of process feed slurry characteristics that occur under site operational conditions.

The grapes are continuously stemmed and crushed in a screw press.  The press juice emerging from the press is reasonably high in suspended solids at ~10% v/v when measured in a test tube centrifuge.  Therefore further clarification of the press juice is inevitably required. The Pennwalt Decanter Centrifuge provides an effective alternative to the conventional screw pressing for processing Grapes.

The grape slurry at 8%-10% v/v insoluble is pumped from tank-3 to the Pennwalt Decanter Centrifuge whereby the centrate juice is produced practically free from suspended solids.  The pomace cake discharges at 65%-70%w/w moisture from the Pennwalt Decanter Centrifuge. The centrate juice from Pennwalt Decanter Centrifuge has ~0.8-1.0% w/w insoluble solids. 

A model P-3400 Pennwalt Decanter Centrifuge would be expected to handle a grape slurry feed rate of ~6.0m3/hr and achieve solids removal of  > 90%. 
Thus the standard Pennwalt Model P-3400 Pennwalt Decanter Centrifuge has a well-demonstrated ability to remove majority of solids from the grape juice.  Further polishing of the centrate juice if required can be carried out with a model P3400 BD Pennwalt Decanter Centrifuge in series downstream to reduce insolubles level to less than 1% v/v in the final juice. It must be recognized that quality and yield are the parameters that can be achieved by means of a correctly featured Pennwalt Decanter Centrifuge in the wine industry for clarification of grape juice.

Prune pulp at a sugar concentration corresponding to 16^o-18^o Brix can be processed by feeding if from the pulper to a Model P-3400 Pennwalt Decanter Centrifuge at ~65^oC or higher, at a capacity of 450 lph to obtain a solids cake discharge containing 25% + total solids and with~ 85% solids recovery.

A PARTIAL LIST OF SUCCESSFUL DEWATERING & CLARIFICATION APPLICATIONS FOR PENNWALT DECANTER CENTRIFUGES