Pulp Washing Defoamer & Black Liquor Antifoam Supplier | INVINO®
Select a pulp washing defoamer by the actual brownstock washer, filtrate tank, screening or black-liquor condition—not by a generic “alkali-stable” label. INVINO-6830 and INVINO-6930 are two modified-silicone emulsion candidates that should be compared at equal active dosage using current mill liquor, then checked for foam control, drainage, deposits and downstream carryover.
Choose by process stage and trial objective
| Process / symptom | First screening candidate | Trial checks | Decision boundary |
|---|---|---|---|
| Brownstock washer vat or shower zone; unstable surface foam | INVINO-6830 | Foam height and decay, mat drainage, shower distribution, filtrate level, active dosage | Approve only if foam and washing indicators improve without new deposits or carryover. |
| Screening, knotter or high-shear liquor circulation | INVINO-6830; include INVINO-6930 if persistence is insufficient | Air entrainment after recirculation, pump stability, screen behavior, cleanliness | A short static collapse result is insufficient; reproduce shear and residence time. |
| Concentrated or hotter black-liquor service | INVINO-6930 | Actual temperature, pH, solids/density, persistence, dispersion, deposit tendency | Do not infer evaporator suitability from washer performance; test the relevant liquor stage. |
| One program proposed for washing plus evaporation | Side-by-side screening of both grades | Separate stage baselines, normalized active dose, carryover, recovery constraints | Use one grade across stages only when mill data show an acceptable operating window. |
Two candidate grades for controlled mill screening
INVINO-6830
Modified silicone emulsion; declared active solids 30.0 ± 1.0%. Use as a first candidate for brownstock washing, screening and filtrate-tank trials. Confirm the current TDS/SDS, storage condition and batch specification before testing.
INVINO-6930
Modified silicone emulsion; declared active solids 30.0 ± 1.0%. Include when a trial requires more persistence in concentrated or hotter liquor. “Upgraded” does not mean universally better: compare at equal active material and process conditions.
Mill-trial workflow
- Define the baseline: record liquor source, furnish, temperature, pH, solids/density, flow, washer load and current feed program.
- Screen with current liquor: compare knockdown and persistence, then repeat after representative shear or recirculation.
- Check process consequences: include drainage, filtrate level, pump behavior, washer cleanliness, deposits and downstream carryover.
- Run a controlled step trial: change one dose or addition point at a time and determine the lowest effective active dosage within the observed operating range.
How this page fits the paper-mill content cluster
Use the pulp and paper defoamer industry center for the full mill portfolio, the papermaking white-water page for wet-end grades, the black-liquor foam-control guide for diagnosis and operating variables, and the dynamic defoaming guide when static screening does not predict machine performance.
Technical FAQ
Q: How should a kraft mill choose between INVINO-6830 and INVINO-6930?
A: Treat the two grades as screening candidates, not automatic substitutions. Start with INVINO-6830 for brownstock washing, screening and filtrate-tank trials; include INVINO-6930 when the liquor is more concentrated, hotter or requires longer persistence. Compare both at equal active dosage under mill liquor conditions and check foam, drainage, deposits and carryover before selecting a feed rate.
Q: Where can a pulp washing defoamer be added?
A: Candidate points include washer vats, shower or wash water, filtrate tanks, stock or liquor lines and selected points before evaporation. The best point depends on where foam is generated, mixing energy, residence time and whether the product reaches the next process stage. Confirm the point with a controlled step trial.
Q: Can one defoamer cover brownstock washing and black liquor evaporation?
A: Sometimes, but performance in a washer does not prove performance in an evaporator. Liquor solids, temperature, residence time, entrainment and downstream recovery constraints differ. Test each stage separately and use one grade across both only when the mill data support it.
Q: Will a silicone defoamer cause deposits or sheet spots?
A: It can if the chemistry, emulsion condition, dosage or addition point is poorly matched. Evaluate dispersion, storage stability, deposit tendency, washer cleanliness and downstream carryover. Do not approve a grade solely from a short foam-collapse test.
Q: What should a mill record during a defoamer trial?
A: Record liquor source, wood furnish, temperature, pH, solids or density, flow, washer load, addition point, active dosage, foam height, drainage or mat behavior, filtrate-tank level, pump stability, deposits and any downstream carryover. Compare against a baseline over a representative operating period.
Technical references
Request grade screening and sample options
Share the pulp stage, liquor source, temperature range, pH, solids/density, current dosage, foam symptoms and downstream restrictions. INVINO can recommend a starting comparison plan; final approval remains subject to mill testing and current product documents.