Scraper Bottom Discharge Centrifuge for Chemical Crystal Dewatering

The Scraper Bottom Discharge Centrifuge is designed for the dewatering, washing, and automatic discharge of filterable chemical crystals after crystallization, reaction, purification, or solvent recovery.

It is suitable for chemical crystal slurry with moderate to high solids content that can form a stable filter cake inside the basket. During operation, mother liquor passes through the filter medium while crystals are retained in the rotating basket. The machine can then complete cake washing, high-speed spin drying, automatic scraping, and bottom discharge within one controlled batch cycle.

This solution helps chemical producers reduce residual mother liquor, improve crystal cleanliness, lower cake moisture before drying, and reduce manual handling during batch production.

Peony provides complete separation support for the section between crystallization and downstream drying.

A typical process arrangement is:

Crystallizer / Reactor → Slurry Buffer Tank → Scraper Bottom Discharge Centrifuge → Filtrate Collection or Recycle → Optional Cake Washing → Crystal Discharge → Dryer / Screen / Packaging

The separated mother liquor can be routed to a mother liquor tank, solvent recovery unit, crystallizer recycle loop, evaporation section, or wastewater treatment system according to the process design.

After dewatering, the crystal cake can be transferred to a vacuum dryer, conical dryer, tray dryer, fluid-bed dryer, screen, mill, or packaging equipment.

Process Evaluation

Our engineers evaluate:

• Chemical crystal type and process route
• Crystal size and particle-size distribution
• Slurry solids concentration
• Mother liquor composition and viscosity
• Cake-forming behavior and filtration rate
• Product purity target
• Required cake moisture
• Cake washing requirement
• Batch capacity and production cycle
• Corrosion condition and solvent compatibility

Equipment Selection

We help customers determine:

• Basket diameter and effective working volume
• Filter medium and support screen configuration
• Feed method and batch loading quantity
• Cake washing system and wash-liquid distribution
• Spin-drying speed and cycle time
• Scraper configuration and bottom discharge arrangement
• Filtrate collection and recycle connection
• Wetted material and seal selection
• Explosion-proof, nitrogen protection, and PLC automation options

The chemical crystal slurry enters the rotating basket lined with filter media.

1. Slurry Feeding
   The crystallized slurry enters the rotating basket through the feed system.
2. Mother Liquor Filtration
   Mother liquor passes through the filter medium and is collected through the filtrate outlet.
3. Crystal Cake Formation
   Chemical crystals are retained inside the basket and gradually form a filter cake on the basket wall.
4. Optional Cake Washing
   Compatible wash liquid can be introduced to reduce residual mother liquor, soluble impurities, salts, residual reactants, or solvent-soluble by-products.
5. Spin Drying
   The basket continues rotating at high speed to remove free liquid from the crystal cake.
6. Automatic Scraping
   After the programmed separation cycle, the scraper removes the dewatered cake from the basket wall.
7. Bottom Discharge
   The dewatered crystals are discharged through the bottom outlet for downstream drying, screening, packaging, recycle, or further purification.

The complete sequence can be controlled through PLC operation to maintain stable filtration, repeatable washing, and automatic batch discharge.

Efficient Mother Liquor Removal

Centrifugal filtration removes mother liquor from the crystal cake before downstream drying. This helps reduce liquid carryover and supports more stable product handling.

Automatic Scraping and Bottom Discharge

The scraper automatically removes the dewatered cake and discharges it through the bottom outlet. This reduces manual unloading and supports repeatable batch operation.

Controlled Cake Washing

An optional wash system can reduce residual mother liquor, soluble impurities, trace salts, residual reactants, or solvent-soluble contaminants trapped between crystals.

Suitable for Filterable High-Solids Crystal Slurry

The centrifuge is designed for chemical crystal slurry with moderate to high solids content and stable cake-forming behavior.

Flexible Material and Safety Configuration

Basket, casing, scraper, seals, filter media, and electrical configuration can be selected according to corrosion conditions, solvent compatibility, operating temperature, and hazardous-area requirements.