Scraper Bottom Discharge Centrifuge for High-Solids Crystalline Slurry Dewatering

The Scraper Bottom Discharge Centrifuge is designed for dense, high-solids crystalline slurry that requires controlled feeding, stable cake formation, centrifugal dewatering, and automatic bottom discharge.

It is particularly suitable when the crystal-to-liquor ratio is high, slurry concentration fluctuates between batches, or upstream crystallization produces intermittent peak loads that require controlled basket filling and reliable cake discharge.

For high-solids slurry, the main challenge is not only liquid removal. The equipment must also handle dense feeding, maintain an even cake layer, avoid basket overload, control cake thickness, and discharge the dewatered crystals reliably. The scraper bottom discharge design is well suited for these requirements.

Peony provides separation support for the process section between crystallization and downstream drying, screening, packaging, or mother liquor recycle.

A typical system arrangement is:

Crystallizer / Evaporator → High-Solids Slurry Buffer Tank → Controlled Feed System → Scraper Bottom Discharge Centrifuge → Filtrate Collection or Recycle → Optional Cake Washing → Bottom Crystal Discharge → Dryer / Screen / Packaging

For high-solids slurry, a buffer tank and controlled feed arrangement are important. They help stabilize slurry concentration, prevent sudden overload, and maintain a more uniform cake layer inside the basket.

The separated mother liquor can be routed to an evaporator, crystallizer circulation loop, brine tank, solvent recovery section, or other designated recycle point.

Process Evaluation

Our engineers evaluate:

• Crystal type and crystal morphology
• Crystal size distribution and fines content
• Slurry solids concentration
• Slurry density and viscosity
• Cake permeability and filtration behavior
• Feed consistency and solids fluctuation
• Required batch capacity
• Target cake moisture
• Cake washing requirement
• Mother liquor recycle route
• Corrosion condition and material compatibility

Equipment Selection

We help customers determine:

• Basket diameter and working volume
• Maximum suitable batch loading quantity
• Feed rate and feed sequence
• Filter medium and support screen configuration
• Cake thickness control
• Washing system and wash-liquid distribution
• Spin-drying speed and cycle time
• Scraper structure and bottom discharge arrangement
• Filtrate collection and recycle connection
• Product-contact material and corrosion-resistant configuration
• PLC automation and overload protection logic

The high-solids crystalline slurry enters the rotating basket lined with filter media.

1. Controlled Slurry Feeding
   High-solids slurry is introduced into the rotating basket at a controlled rate to avoid uneven loading and excessive cake thickness.
2. Mother Liquor Filtration
   Mother liquor passes through the filter medium and is collected through the filtrate outlet.
3. Crystal Cake Formation
   Crystals are retained inside the basket and gradually form a dense filter cake on the basket wall.
4. Optional Cake Washing
   Compatible wash liquid can be introduced to reduce residual mother liquor, soluble salts, or other impurities retained within the cake.
5. Spin Drying
   The basket continues rotating at high speed to remove residual liquid from the crystalline cake.
6. Automatic Scraping
   After the programmed cycle, the scraper removes the dewatered cake from the basket wall.
7. Bottom Discharge
   The crystals are discharged through the bottom outlet for drying, screening, packaging, recycle, or further processing.

The complete cycle is controlled through PLC operation to maintain stable loading, repeatable dewatering, and automatic cake discharge.

Material Selection and Configuration Options

Suitable for Dense Crystal Slurry

The centrifuge is designed for slurry with moderate to high crystal concentration. It can handle dense, filterable crystal feed while maintaining a controlled separation cycle.

Controlled Cake Thickness

Feed rate, batch loading quantity, and basket filling level can be controlled to avoid excessive cake thickness. This helps maintain better filtrate flow and more stable dewatering performance.

Reduced Mother Liquor Carryover

Centrifugal filtration and spin drying remove mother liquor from the crystal cake before downstream drying. This helps reduce liquid carryover and lowers the drying load.

Automatic Scraping for Dense Cake Discharge

High-solids slurry can form a thick cake inside the basket. The scraper mechanism removes the dewatered cake automatically and discharges it through the bottom outlet, reducing manual cleaning and handling.

Flexible Integration With Crystallization Lines

The centrifuge can be integrated with evaporators, crystallizers, MVR systems, slurry tanks, mother liquor recycle loops, dryers, and packaging systems to form a complete high-solids crystal handling section.