High-Quality Control Disodium Hydrogen Phosphate (Na2HPO4) MEE Evaporation & Vacuum Crystallization Line
Engineered multi-effect falling/thin-film evaporation with integrated vacuum crystallization to produce high-purity Disodium Hydrogen Phosphate crystals with consistent particle size, low moisture, and reliable batch-to-batch quality. Optimized steam economy, compact footprint, and full PLC automation make it ideal for fine chemicals and food/pharma-adjacent applications.
Tight Quality Control
Online density/conductivity, mother-liquor recycle logic, and crystal-size control (saturation curve & residence time) to meet specification consistently.
Steam Economy
Each effect reuses vapor from the previous effect as the heating medium; optional TVR/MVR modules further cut utilities.
Clean Operation
Vacuum, low-temperature evaporation minimizes product degradation; mirror-polished tubes reduce scaling and simplify CIP.
Process Description
- Feed Preparation: Filtered Na2HPO4 solution is metered to the pre-heater and first effect.
- Multi-Effect Evaporation (MEE): Falling-film evaporation across 2–4 effects. First effect uses live steam; subsequent effects use secondary vapor as heating media.
- Vacuum Crystallization: Concentrated liquor flashes/ages under vacuum to the selected supersaturation; crystal seeds can be dosed to tune PSD.
- Solid–Liquid Separation: Crystals are discharged to centrifuge/pressure filter; mother liquor is recycled to the effects for yield improvement.
- Drying & Packaging: Low-temperature drying to target LOD; screened and packed per specification.
System Structure
Effects (heaters & separators), pre-heaters, vacuum crystallizer, condenser & vacuum set, feed/circulation/discharge/condensate pumps, crystal-handling unit (seed tank, centrifuge), CIP skid, and complete instrumentation (T/P/vacuum/flow/level/cond.).
Key Features
- Capacity: 500 kg/h – 80 t/h water evaporation.
- Materials: SS304 / SS316L (others on request).
- Low-temperature operation: Gentle vacuum evaporation limits hydrolysis and discoloration.
- High concentration ratio: Falling-film hydrodynamics handle viscous brines with short residence time.
- Automation: PLC/HMI with recipe & historian; interlocks for vacuum/level/temperature.
- CIP friendly: Seamless, mirror-polished tubes simplify cleaning and mitigate scaling.
- Flexible integration: TVR/MVR add-ons, mother-liquor recycle, optional seed dosing and crystal classification.
Typical Three-Effect Falling Film — Illustrative Specifications
| Parameter | Unit | Value (Example) |
| Evaporation capacity | kg/h | 3,000 – 50,000 |
| Raw steam consumption | kg/h | ~30–40% of single-effect (e.g., 900 kg/h @ 3,000 kg/h duty) |
| Evaporation temperature (1st / 2nd / 3rd) | °C | ~99 / 76 / 53 (vacuum) |
| Steam pressure for 1st effect | MPa (abs) | 0.6 – 1.0 |
| Feed solids (Na2HPO4) | % w/w | 8 – 12 (typical) |
| Crystallizer outlet | — | Target supersaturation per grade; mother-liquor recycle |
Quality & Compliance
- Process analytics: density/conductivity, temperature, vacuum, and flow trending for batch traceability.
- Welds & pressure parts to applicable standards; material certificates available.
- Validation support for cleaning and product changeover where required.
Delivery Workflow
Feed & target → Lab/pilot (optional) → Process & heat balance → Detailed engineering & fabrication → Installation & commissioning → Performance test & training → O&M support.
