Product quality first. An internal draft tube directs circulation while a baffle separates the growth zone from a fines-removal zone — classified-fines destruction produces large crystals (0.5–2 mm) with a narrow distribution that centrifuges easily and carries little mother liquor.
Reference ranges under typical operating conditions on inorganic salt systems.
Two zones, two jobs: the draft tube circulates the growing crystal population; the baffle annuity classifies it — fines leave, product stays.
Slurry → Draft tube (1–2 m/s growth circulation) → Baffle annulus (0.5–1 m/s fines elutriation) → Fines dissolved/removed → Product crystals to discharge
Fines removed at the baffle are dissolved and recycled — the crystal population that remains grows into the narrow, large-crystal distribution DTB is known for.
The internal draft tube directs flow at a controlled 1–2 m/s — the growing population stays suspended and mixed.
Inside the draft tube, crystals grow under controlled supersaturation delivered by the Dimension C method of the plant.
The baffle annulus runs at 0.5–1 m/s: fine crystals are elutriated out, dissolved and returned — keeping them out of the product.
Product crystals leave at 0.5–2 mm — narrow PSD, easy centrifugation, little mother-liquor carryover.
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.
Chemical systems where large crystals with narrow PSD justify classified growth.
Chemical-configuration mapping from the crystallizer-type technical reference; final selection requires solubility data, impurity profiling and crystallization trials.
DTB is the answer when product spec (PSD, centrifuge yield, mother-liquor carryover) is the priority and the feed is not extreme.
DTB (draft-tube-baffle) crystallizers grow 1.0-3.0 mm uniform crystals with CV under 20% at 10-30% lower energy than forced circulation. Components, six-step cycle, the three parameters that set quality, a chlor-alkali
FC, DTB, or Oslo? The complete industrial crystallizer selection guide: crystal size 0.2-0.5 vs 0.5-1.5 vs 2-5 mm, supersaturation methods, DP variant, five-step decision tree, economics, and scale-up from 30
Indicative ranges aggregated from published supplier specifications of draft-tube-baffle crystallizer builders (fertilizer, food and chemical executions). For route screening only — not a process guarantee for any specific project.
Ranges aggregate published specifications from draft-tube-baffle crystallizer builders. Figures are supplier-published indicative values for screening; a project number requires crystallization kinetics on your liquor and the target PSD specification.
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; draft-tube velocity, baffle cut and fines-dissolution rate are project-specific and set at design.
FC, DTB, or Oslo? The complete industrial crystallizer selection guide: crystal size 0.2-0.5 vs 0.5-1.5 vs 2-5 mm, supersaturation methods, DP variant, five-step decision tree, economics, and scale-up from 30
DTB (draft-tube-baffle) crystallizers grow 1.0-3.0 mm uniform crystals with CV under 20% at 10-30% lower energy than forced circulation. Components, six-step cycle, the three parameters that set quality, a chlor-alkali
DTB is a Dimension D crystal growth configuration — the selection logic is explicit: product quality first, with stable crystal size, easy centrifugation and minimal mother-liquor carryover. It pairs with any Dimension C supersaturation method (evaporative, cooling, vacuum cooling). d50 and PSD outcomes depend on residence time, fines-management settings, slurry density (15–30 wt% band) and the driving-force profile. All figures are indicative ranges for preliminary screening, not a process guarantee.
Recurring questions from engineers choosing a growth configuration.
It creates a low-velocity annulus (0.5–1 m/s) where fine crystals are elutriated out of the growth zone, dissolved and recycled. Removing fines continuously is what keeps the product distribution narrow — without it, the fines compete for solute and the PSD widens.
DTB delivers 0.5–2 mm with classified-fines removal — preferred when downstream centrifugation throughput is the priority. Oslo produces larger crystals (1–5 mm) with very low fines — preferred when crystal size and purity matter most. Both reach high purity; the choice depends on which downstream property you value.
Good but not FC-grade. DTB tolerates moderate scaling tendency; on high-TDS, heavily scaling mixed-salt liquors, FC's high-velocity loop is the reliable choice. Putting classified equipment on an unstable feed trades availability for PSD you may never collect.
The 15–30 wt% band is a primary size lever — higher slurry density gives more crystal surface area, lower per-crystal supersaturation and larger product. It is one of the main operating variables, tuned against the fines-removal rate.
Send us the chemical system, target PSD and purity, and feed conditions. We will return a preliminary DTB vs. FC 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.
