Engineering reliability first. An external loop circulates a crystal slurry at 2–3 m/s through the heater and back, relieving moderate flash-generated supersaturation on suspended crystals. Medium crystals, wide distribution — and continuous stable operation on the high-TDS, scaling, mixed-salt systems where anything else stops.
Reference ranges under typical operating conditions on inorganic salt systems.
The same circulating architecture as forced-circulation evaporation — with crystal slurry control added as the design objective.
Slurry → Circulation pump → Heater (ΔT ≤10 °C, no wall boiling) → Flash in vapor body → Supersaturation relieved on suspended crystals → Loop
Supersaturation never touches a hot wall — it is created by the flash in the vapor body and consumed by the suspended crystals in the loop.
The external pump keeps a crystal slurry moving at 2–3 m/s — nothing settles, nothing scales undisturbed.
The heater warms the slurry without boiling it — the ≤10 °C rise keeps the tube wall out of the nucleation business.
In the vapor body the slurry flashes; concentration crosses saturation and moderate supersaturation appears.
Crystals in the loop consume the supersaturation; product slurry is drawn off continuously to separation.
Three vessel configurations, three priorities: FC puts engineering reliability first, DTB puts product quality first, Oslo puts crystal quality first.
d50 ranges reflect typical operating distributions on inorganic salt systems; actual PSD depends on residence time, fines management, seed control and the cooling/evaporation profile.
FC is the answer when fouling resistance and on-stream time outweigh crystal size; the wrong answer when product spec needs classification.
An FC (forced-circulation) crystallizer is the industrial workhorse for high-viscosity, fouling-prone and impurity-laden liquors. This guide explains its structure, working cycle, key design parameters, MVR integration and how it compares
Indicative ranges aggregated from published supplier specifications of forced-circulation crystallizer builders (salt, ZLD brine and chemical executions). For route screening only — not a process guarantee for any specific project.
Ranges aggregate published specifications from forced-circulation crystallizer builders (salt, wastewater and ZLD brine executions). Figures are supplier-published indicative values for screening; a project number requires heat and mass balance on your feed, scaling chemistry and PSD target.
Each module is selected on feed chemistry and duty — the envelope column gives published operating ranges per module type, not a single-project specification.
Module envelopes follow the published supplier data above; circulation rate, heater ΔT and seed rate are project-specific and set at design.
An FC (forced-circulation) crystallizer is the industrial workhorse for high-viscosity, fouling-prone and impurity-laden liquors. This guide explains its structure, working cycle, key design parameters, MVR integration and how it compares
FC is a Dimension D crystal growth configuration — it pairs with any Dimension C supersaturation method, and it is the typical carrier for evaporative crystallization on difficult liquors. The selection logic is explicit: accept higher energy consumption in exchange for continuous stable operation on high-salinity, high-viscosity, scaling-prone systems. What you give up is crystal size control — no internal classification means wide PSD. All figures are indicative ranges for preliminary screening, not a process guarantee.
Recurring questions from engineers choosing a growth configuration.
No — that is the trade. FC has no internal classification; crystal size lands at 0.2–0.8 mm with a wide distribution. If the product spec (or downstream centrifuge yield) needs narrow PSD, the answer is DTB with classified-fines removal, not a tuned FC.
You feel it in three places: product spec — undersized d50 fails downstream handling; availability — putting Oslo on a fouling-prone feed drives cleaning cycles that kill on-stream time; yield — fines escaping the crystallizer carry dissolved product back and increase purge.
Because once evaporation is the supersaturation driver, supersaturation is high and scaling accompanies it. The FC body at 2–3 m/s tolerates what a classified bed would not — that is exactly the ZLD mixed-salt duty.
The architecture is identical — pump, heater, flash body, loop. This page covers crystal-side design: slurry control, residence and discharge. The evaporation-side logic (stable concentration of difficult liquors) lives on the FC evaporation page.
Send us feed composition, fouling tendency, target PSD and purity. We will return a preliminary FC vs. DTB vs. Oslo screening with indicative crystal size — not a brochure.
Send your feed characterization (TDS, COD, main salts, viscosity), throughput and product targets — we respond with a preliminary process route within two business days.
