Granulators offer efficiency and flexibility through their ability to manage feedstock variation and produce a wide range of finished product. Roll granulators boast increased bulk densities, durable granules, and lower operating costs that are typically associated with crushing circuits. In addition, granulators deliver less fines and consistently sized product, often seen in wet granulation or prilling.
Roll granulators efficiently shear feed passing through the nip zone. They minimally impact feed particles, which lessens fines and narrows the uniformity index of product. Plant operators profit from this advantage. Consequently, they can target a specific size guide number (SGN). Superior granule mechanical properties result in less breakage during storage, transport, blending and spreading.
Tying the benefits of dry granulation to process development
Dry granulation satisfies key aspects of process analysis and development. The leading drivers in process development are capital investment, material properties and perceived value for end-users.
First, minimised operation expense generates long-term success and provides an upper hand to volatile commodity prices and fluctuating currency. Secondly, material properties drive acceptable processes in the manufacturing of granular products. Dry agglomeration generally reduces use of binders and allows blending prior to compaction. Producing adaptive primary fertilizers and micronutrient combinations suits regional, seasonal or specific crop needs. Thirdly, dense product with minimal fines improves perceived value for end-users.
Pressure agglomerated feedstock followed by dry granulation delivers superior results in three key drivers of granular product success. Fulfilling the following points results in better granulation process development:
- Particle size: granules with a higher mean size and uniformity spread more consistently are less likely to segregate.
- Density: higher density product cultivates a wider spread pattern.
- Strength: durable particles resist breakages and minimise fines.
Dry granulation, paired with pressure agglomeration or other crushing methods, results in more on-size particles, denser product, and noticeable durability, when compared to other methods.
This is an article written for World Fertilizer's January/February 2018 issue and abridged for the website. Subscribers can read the full issue by signing in. Non-subscribers can access a preview of the issue here.