How it works
Agglomeration is a size-enlargement process: two particles collide and, if they stick, merge into a single larger particle of their combined volume. Whether a collision leads to lasting growth depends on the particles meeting, on a binding mechanism — a liquid binder bridge, van der Waals forces, or partial melting — and on the impact being gentle enough not to rebound or break the bond.
How fast the population grows is governed by how often particles collide and how likely each collision is to succeed, which in turn depends on particle size, concentration, and the operating conditions in the vessel. Larger, more numerous, or wetter particles collide and bind more readily, so the whole distribution shifts toward coarser sizes over time.
Total solid mass is conserved — agglomeration only redistributes mass across size classes, turning fines into coarser granules rather than creating or destroying material.
The model
Dyssol Pro solves a dynamic population balance over the particle population by number: particles are born into a size class when smaller ones agglomerate into it and die from a class when they grow into a larger one, with the inlet and outlet streams completing the balance at every time point of the flowsheet.
The rate at which particles combine is governed by an agglomeration kernel — the physical rule for how collision frequency depends on the two particle sizes — together with a size-independent rate constant that scales the overall growth intensity with the operating conditions. Total solid mass is conserved; the balance simply moves mass up the size distribution over time, tracking particle size as the primary property.
On this basis Dyssol Pro covers size-enlargement duties from fluidized-bed and high-shear agglomerators to drum, pan, and continuous mixer granulators, and even growth behavior beyond the standard description can be brought into the flowsheet.
Equipment this model can represent
Any process where particle collision and coalescence drive size enlargement.
Fluidized bed agglomerators
Bed agglomeration where suspended particles collide and bind into larger structures.
High-shear granulators
Intensive mixing where impeller-driven collisions promote rapid agglomerate growth.
Batch granulators
Drum, pan, and mixer granulators operated batch-wise for controlled size enlargement.
Continuous mixer granulators
Continuous units where coalescence governs the product size distribution.
Typical engineering studies
What teams investigate with the agglomerator model.
Homogeneity studies
Assess how uniformly agglomerates develop across the population under given operating conditions.
Moisture distribution
Study moisture in connected flowsheets when binder or liquid streams feed the growth zone.
Particle size distribution
Track the full PSD evolution from feed fines to the agglomerated product.
Agglomeration efficiency
Quantify growth and the conversion of fines into product across operating conditions.
Process-parameter sensitivity
Map how growth rate and residence time move the product size.
Model-based Design of Experiments
Plan and screen experiments in simulation before running them on the plant.
Scale-up and optimization
Carry validated parameters from lab to production and optimize against product targets.
Application example
Validated population-balance agglomeration
A demonstration flowsheet (Agglomerator.dflw) ships with Dyssol Pro, and the population-balance method behind dynamic agglomeration simulation was published and validated against reference solutions.
Technical FAQ
How can I improve agglomerate strength without increasing binder usage?
Strength comes from the number and strength of solid bridges and the contact area between primary particles, so denser packing, longer consolidation, and a binder of the right viscosity often help more than simply adding binder. In Dyssol Pro you run operating-window studies on residence time, growth, and binder input to reach the target size at lower binder use before committing to lab trials.
Why are my agglomerates breaking apart after drying?
Post-drying breakage usually means the binder bridges shrink or embrittle as moisture leaves, or thermal stress cracks them — gentler drying and a binder that stays ductile help. In Dyssol Pro you connect the agglomerator with the downstream dryer and handling units in one flowsheet to see how moisture and thermal load evolve, which localizes whether the problem starts in growth, drying, or transport.
How do I choose the right binder for powder agglomeration?
The binder is matched to the powder on wettability, bridge strength, viscosity, and product compatibility. Dyssol Pro propagates a binder’s captured effect through the growth and nucleation parameters across the process and predicts the downstream PSD.
What causes oversized lumps in an agglomeration process?
Oversize comes from local over-wetting, excessive residence, or uncontrolled coalescence in the growth zone. With a population-balance growth model Dyssol Pro lets you study how growth rate, liquid input, and residence time drive the coarse tail of the PSD and screen for operating points that suppress oversize.
How can I control particle size distribution in an agglomerator?
PSD is governed by the balance of nucleation, growth, and breakage, set through binder rate, mixing intensity, and residence time. PSD is a first-class quantity in Dyssol Pro: the agglomerator tracks the full distribution, so you can run sensitivity and optimization studies on the parameters that shape it across the connected process.
What is the difference between wet agglomeration and dry agglomeration?
Wet agglomeration uses a liquid binder that forms bridges and then solidifies; dry agglomeration relies on pressure and van der Waals or mechanical interlocking with no added liquid. In Dyssol Pro you represent the relevant mechanism through the model parameters and compare the two process variants in one flowsheet.
How do impeller speed and residence time affect agglomerate size?
Higher impeller speed raises collision frequency but also breakage, so size peaks at an optimum, while longer residence grows particles until breakage balances growth. These map onto growth parameters and holdup in Dyssol Pro, so you vary them in sensitivity studies to see the effect on size and throughput before plant trials.
How can I reduce dust formation during agglomeration?
Dust is unagglomerated fines, reduced by more effective wetting and nucleation and by recycling fines back into the growth zone. In Dyssol Pro you connect the agglomerator with cyclone and gas-filter units and study how much fines and dust leave with the gas stream under different operating points.
What process parameters influence agglomerate porosity?
Porosity is set by consolidation — binder content, compaction forces, and residence time — with denser packing giving lower porosity. Dyssol Pro tracks the residence time and growth that drive consolidation, so you can study how operating points move toward denser, lower-porosity granules.
How do I scale up an agglomeration process from lab to production?
Reliable scale-up preserves the growth kinetics and the wetting and mixing regime, transferring material parameters rather than geometry alone. Dyssol Pro is built for this: fit model parameters to lab data, then run the validated model at production scale inside the full flowsheet to check feasibility before commissioning.
How can I prevent uncontrolled growth in an agglomerator?
Runaway growth comes from over-wetting or too little breakage and recycle; capping the binder rate and closing the circuit with classification stabilizes it. Dynamic simulation of growth and recycle in Dyssol Pro identifies the stable operating windows and control settings that avoid it.
Why does my agglomeration process produce too many fines?
Excess fines mean nucleation is outpacing growth, or agglomerates are breaking — usually under-wetting or too much mechanical stress. In Dyssol Pro you study the fines fraction of the PSD against growth and breakage parameters and against recycle load in the connected flowsheet.
How does liquid spray droplet size affect agglomerate formation?
Droplet size sets the nucleation regime: drops large relative to the particles nucleate big granules quickly, while fine drops spread binder for steadier growth. Droplet effects enter Dyssol Pro through nucleation parameters, so you can study how changing them shifts the resulting PSD.
How can I optimize binder concentration for agglomeration?
There is an optimum liquid-to-solid ratio that drives the target growth without over-wetting — too little starves growth, too much makes lumps. Once the binder effect is parameterized in Dyssol Pro, use the integrated optimization tool to search binder concentration against a target product property.
What causes agglomerates to be too soft or too friable?
Weak granules come from thin or brittle binder bridges, insufficient consolidation, or excessive porosity. In Dyssol Pro you can couple a custom strength or breakage correlation through Model Maker and use the simulation to study which process drivers move it.
How do I model wetting and nucleation in agglomeration?
Wetting and nucleation describe how binder droplets contact and immobilize primary particles to form the first agglomerates. This is core to the unit: population-balance agglomeration in Dyssol Pro represents nucleation and growth, and Model Maker lets you implement specific wetting and nucleation kinetics.
What is the best way to measure agglomerate quality?
Quality is measured as size distribution, strength, porosity, and dissolution behavior, using sieving, texture testing, and imaging. Dyssol Pro complements measurement by predicting size and PSD, so you know what to expect and can reconcile model and measurement.
How does powder wettability influence agglomeration behavior?
Poorly wetting powders resist nucleation and need more energy or a surfactant, while readily wetting powders nucleate and grow easily. Wettability is a material input reflected through nucleation parameters in Dyssol Pro, whose influence on growth and PSD you then study in the flowsheet.
How can I reduce recycle load in an agglomeration circuit?
Recycle load falls when more feed reports to product in a single pass — better on-size yield through nucleation and growth control and the right screen cut. Dyssol Pro simulates recycle loops, so you can study how operating points and screen cut sizes change the recycle load around the agglomerator.
What are typical control strategies for continuous agglomeration?
Common strategies regulate the binder rate to a moisture or size target and manage the recycle of fines and crushed oversize to hold the PSD steady. Dynamic simulation of startup, shutdown, and disturbances in Dyssol Pro lets you test these strategies and operating windows before implementing them on the plant.