Steel belt-based granulation systems

Paul Boughton

Sandvik Process Systems, the company behind both the world’s first steel belt and the Rotoform pastillation system now widely employed across the oil, chemical, plastics and food industries, will use this year’s Powtech fair to highlight the versatility and capacity of its systems.
With granulation systems available for applications as diverse as foodstuffs, subcooling melts, thixotrpy, abrasive and corrosive products, Sandvik Process Systems offers one of the widest ranges of process solutions on the market.

Working examples of two steel belt-based granulation systems – the Rotoform 3000 and Rotoform HS (high speed) models – will provide the focus of the company’s stand this year’s Powtech fair.
The steel belt cooler is designed as an integrated system, incorporating everything needed to complete the solidification process, from Rotoform feeding, steel belt and automatic belt tracking to release agent, discharge device and exhaust air system.
Each of the nine different members of the Rotoform family has been designed to meet specific process requirements and all are based around the same basic concept that has led to more than 1500 Rotoforms being installed around the world, making it the most popular system of its kind.
At the heart of every system is a special drop depositor – the Rotoform itself – which feeds droplets of the molten product onto a continuously running steel belt. This is cooled by water from the underside, rapidly solidifying the product. The droplets are discharged in the form of dry, uniform, free flowing and dust-free pastilles – ideal for transport, storage and subsequent processing.
It is a highly flexible process capable of handling molten products at temperatures of up to 320ºC and viscosities up to 50.000 cP. Depending on the system used, pastilles can be produced in diameters from 1 mm up to 30 mm, and the diameter can be adjusted on the machine or – in the case of more major change – by switching components.
Another benefit to growing numbers of users is the environmental-friendliness of the system. The fact that there is no contact between cooling water and the product being processed means no risk of cross contamination, while fast cooling times mean little or no exchange of gases, vapour or oxygen between chemical product and the surrounding atmosphere.
The Rotoform 3000 is the standard unit and is widely used for products such as hot melt adhesives, resins, sulphur and waxes. However, some oil and gas refineries need higher capacity solutions and it was to meet this need that the HS model was developed.
Through the use of a bigger rotating shell, reducing the centrifugal force on the droplet shape – Sandvik have been able to produce a system that delivers up to 2x the throughput of a standard Rotoform while maintaining control of end product quality and delivering a consistent pastille with a regular, hemispherical shape.
Sandvik can also supply conveying, storage and loading facilities, together with associated control systems. This ability to offer a complete solution – with single source responsibility – is one of the company’s key strengths, enabling it to undertake end-to-end project management, from feasibility studies and front end engineering and design (FEED), through to complete engineering procurement construction (EPC) packages.
Sandvik has invested in a network of test centers where all nine Rotoform types are available for demonstration and tests on customers’ own products. In addition, transportable units have also been developed to allow tests and pilot production to be carried out on customers’ own sites.

For more information,

Recent Issues