Crystallizer Selection Tool

Six inputs — chemistry, solubility behavior, thermal sensitivity, crystal-size target, throughput and corrosivity — route your system to one supersaturation method and rank the four crystallizer configurations against each other.

TOOL VISUAL

What This Tool Recommends
Method → Configuration

Two answers, in the order an engineer needs them. First a supersaturation method — evaporative, cooling, vacuum adiabatic flash, or reaction drowning-out — selected by the solubility-vs-temperature behavior of your system. Second a ranked shortlist of the four configurations — FC, DTB, Oslo, stirred-batch — scored on crystal size, scale, purity and fouling tolerance.

Why Selection Matters
Mismatch = Failure Mode

Every configuration fails a specific way. FC cannot classify — battery-grade fines carry impurities to the centrifuge. Oslo cements on scaling brines. DTB never reaches 5 mm territory. The wrong method is worse: cooling a flat-curve system buys no yield at all. The tool screens these mismatches out before the first budget number.

Step 1 · Describe Your System

Run the Selection

Six inputs, two outputs: a recommended supersaturation method and a scored configuration shortlist. Nothing is stored, nothing is sent.

Your System

Six inputs · Step 1 of 2

Recommendation

Route + configuration ranking · Step 2 of 2

Fill in the six inputs and press Get Recommendation. The route card and the configuration ranking appear here.
Screening output only. Final method and configuration selection is confirmed against lab solubility data and a project heat-and-mass balance — see the solution line.
ConfigurationCrystal SizePurityFouling ToleranceScale
FCFORCED CIRCULATIONFine–mediumMediumHighVery large
DTBDRAFT-TUBE-BAFFLEMedium–coarseHighMediumLarge
OSLOFLUIDIZED BEDCoarseVery highLowMedium
Stirred-batchJACKETED / AGITATEDMediumHighMediumSmall

The static scoring basis behind the ranking. Green = strength, amber = workable, grey = weak. Hard exclusions override scores: FC cannot deliver coarse targets, Oslo cannot survive scaling feeds at fine targets.

Reference · Selection Logic

How to Choose a Crystallizer

The reasoning the tool automates, written out. Four methods, four configurations, and how each input moves the answer.

First choose the method — the solubility curve decides

Method selection precedes equipment selection, always. The solubility-versus-temperature curve of your system opens and closes routes before any vendor is consulted:

  • Flat curve (NaCl, Na₂SO₄, ZLD brines): cooling buys almost nothing. Evaporative crystallization — solvent removal — is the only productive route. These trains are typically MVR- or multi-effect-fed.
  • Steep curve (>3× from 20 → 80 °C): cooling crystallization reaches yield directly. If the liquor fouls cooling surfaces or the product is thermally sensitive, move to vacuum adiabatic flash — supersaturation without a heat-transfer surface.
  • Moderate curve: combine both levers. Evaporative-cooling hybrids are the fertilizer-salt standard: solvent removal and sensible-heat cooling act together.
  • Inverse solubility (Li₂CO₃): less soluble hot than cold. Reaction drowning-out above 90 °C is the industrial route — evaporative and cooling methods do not apply.

Then choose the configuration — size, scale, purity, fouling

Four configurations span the industrial range, and each owns a territory:

  • Forced-circulation (FC): the workhorse for scaling brines and ZLD salt. Highest fouling tolerance, very large scale, d50 0.2–0.8 mm. No classification — purity depends on upstream control.
  • Draft-tube-baffle (DTB): classification and fines destruction for fertilizer and battery chemicals. d50 0.5–2.0 mm, high purity at large scale.
  • Oslo fluidized bed: coarse premium crystals, d50 1–5 mm, very high purity — but demands a clean, low-scaling liquor and stays medium scale.
  • Stirred-batch: multi-product flexibility at small scale. Never economical beyond a few t/h.

How the six inputs map onto the answer

Chemistry sets property assumptions and triggers special routes (Li₂CO₃ → reaction). Solubility sensitivity elects the method. Thermal sensitivity vetoes surface-boiling routes. Crystal-size target and throughput drive the configuration score — weighted double, because a size or scale mismatch is the failure you cannot commission around. Purity and fouling tolerance complete the score, maximum 11 points. Corrosivity changes only materials of construction, never the ranking.

Degenerate cases worth knowing

Very-coarse target on a scaling brine: the Oslo wants clean liquor, the FC cannot reach the size — the honest answer is a DTB with a polishing loop, or a re-specified target. Fine target with battery-grade purity: FC is excluded on classification, Oslo on fines control — DTB with fines destruction is the route. Flat curve with thermal sensitivity: low-temperature vacuum evaporation holds boiling down while the solvent leaves. The full configuration detail lives on Crystallization Technologies.

Applicability & Disclaimer

This tool reproduces the screening logic a process engineer applies on first contact: solubility behavior elects the method, size and scale elect the configuration. It is a routing aid, not a design.

Scores use indicative industrial ranges. Real selection requires measured solubility data on your actual liquor, a bench crystallization test, and a project heat-and-mass balance before any equipment is specified.

Need Crystal-Size Targets Validated?

Send a liquor sample and your d50 and purity spec. We run bench crystallization on the real material and return a PSD curve, a recommended configuration, and the scale-up basis — data, not a brochure.

Request a Proposal

Send your feed characterization (TDS, COD, main salts, viscosity), throughput and product targets — we respond with a preliminary process route within two business days.