Position in the Production Line Stage 03

01
Raw Material Prep
02
Reaction
03
Washing ← Here
04
Drying & Crushing
05
Blending & Sieving

After the etherification reaction, the crude CMC or PAC is neutralized and washed with aqueous ethanol to remove by-products — primarily sodium chloride and sodium glycolate — which would otherwise reduce product purity and affect performance. This centrifuge handles the first-wash stage, separating the washed solid product from the ethanol-water wash liquor, which is simultaneously sent to the alcohol recovery distillation system for reuse.

The efficiency of this separation step directly affects the purity of the final product and the economics of solvent recovery. The centrifuge must operate reliably in an ethanol-rich atmosphere, making the sealed, explosion-proof design essential for both product quality and operational safety.

Available Types

Horizontal Peeler Centrifuge
Continuous / Semi-Continuous Operation
Suitable for higher-capacity production lines. Continuous or semi-continuous discharge with automatic cake cutting and discharge mechanism. Higher throughput with consistent separation performance. Preferred for large-scale CMC and PAC plants.
Vertical Basket Centrifuge
Batch Operation
Batch operation with top or bottom discharge. Lower capital cost and simpler maintenance. Suitable for small to medium capacity lines or where batch-to-batch flexibility is required. Commonly used in pilot plants and smaller production facilities.

Type selection depends on your target production capacity, batch size, and process design. ZHAOYUAN's reference first-wash installation uses the horizontal continuous type. Contact us with your requirements for a recommendation.

Key Design Features

  • SUS316 stainless steel throughout — all product-contact components fabricated in SUS316 for superior corrosion resistance against the acidic and chloride-containing wash liquor environment in CMC/PAC washing operations.
  • Sealed explosion-proof design — fully sealed housing with explosion-proof electrical components rated for hazardous areas. Essential for safe operation in ethanol-rich wash environments where flammable vapor concentrations are present.
  • Designed for CMC / ethanol wash systems — specifically suited for aqueous ethanol wash liquor used in CMC and PAC purification, handling the CMC-ethanol slurry from the first-wash stage.
  • Dual-motor drive for continuous separation — the horizontal decanter design uses a main bowl drive motor paired with a smaller differential/scroll drive motor (30 kW / 7.5 kW), giving independent control of bowl speed and cake conveying rate for stable, continuous solid-liquid separation.
  • Simultaneous alcohol recovery integration — filtrate outlet designed for direct connection to the alcohol distillation column, enabling continuous solvent recovery during the washing and separation operation.
  • Rated for the full ethanol wash temperature range — design temperature of 65°C and design pressure of 0.09 MPa.G comfortably cover the ambient operating temperature and atmospheric pressure of the first-wash liquor stream, giving a safety margin above normal process conditions.

Technical Parameters

ParameterOperating ConditionDesign Condition
Medium CMC, ethanol
Temperature Ambient 65°C
Pressure Atmospheric 0.09 MPa.G
ParameterSpecification
Product-Contact Material 316 stainless steel
Overall Dimensions 4500 × 1100 × 1400 mm
Drive Power 30 kW (main bowl drive) / 7.5 kW (differential/scroll drive)
Single Unit Weight 3,550 kg
Operating Environment Explosion-proof sealed — suitable for ethanol atmospheres
Wash Medium Aqueous ethanol wash liquor from the first-wash stage
Capacity Custom — sized to production line throughput

Specifications above are from a completed reference project. Equipment is sized to your production capacity and process conditions — contact us for a tailored proposal.

Frequently Asked Questions

What does the centrifuge do in a CMC or PAC production line?

After etherification, the crude CMC or PAC slurry contains reaction by-products — mainly sodium chloride and sodium glycolate — dissolved in the ethanol-water wash liquor. The centrifuge performs solid-liquid separation, spinning out the wet CMC/PAC cake from the liquid stream. The separated liquor is sent to the alcohol distillation column for ethanol recovery and reuse, while the washed solid cake proceeds to drying.

Why does this centrifuge use two drive motors?

Horizontal decanter-type centrifuges use a twin-drive configuration: a main motor rotates the outer bowl at high speed to generate centrifugal force for separation, while a smaller differential (scroll) motor drives the internal screw conveyor at a slightly different speed to continuously convey the separated solids toward the discharge end. This is why the drive power is listed as two values (30 kW main / 7.5 kW differential) — it is standard for continuous horizontal decanter centrifuges rather than a fault or duplication.

Why is this called the "first-wash" centrifuge?

CMC and PAC washing is typically carried out in multiple stages to progressively reduce salt content (sodium chloride and sodium glycolate) to the target product specification. The first-wash centrifuge handles the initial, highest-concentration separation immediately after etherification, before the product moves on to subsequent wash and separation stages. Multi-stage washing balances product purity against ethanol consumption and wastewater volume.

Why is 316 stainless steel used instead of 304?

The first-wash liquor contains dissolved sodium chloride and residual acid from the neutralization step. Chloride ions are aggressive toward standard 304 stainless steel, causing pitting corrosion over time. 316 stainless steel contains molybdenum, which significantly improves resistance to chloride-induced pitting and crevice corrosion — making it the appropriate material choice for equipment in direct contact with the chloride-rich wash stream.

Why is the design temperature (65°C) higher than the normal operating temperature?

The first-wash liquor normally runs at ambient temperature under atmospheric pressure. The equipment is nonetheless designed and pressure-tested to withstand 65°C and 0.09 MPa.G — providing a safety margin above normal operating conditions to accommodate process upsets, warm wash liquor recycled from upstream stages, or seasonal ambient temperature variation, without derating the equipment.

Can ZHAOYUAN size a centrifuge for my target production capacity?

Yes. The specifications on this page reflect a completed reference project. Centrifuge type (horizontal decanter or vertical basket), bowl size, drive power, and throughput are engineered to match your target annual production capacity, wash liquor concentration, and downstream alcohol recovery system design. Contact ZHAOYUAN with your target capacity for a tailored equipment specification.