Update on fluidised drum granulation technology and its applicability for different fertilisers

Ammonium nitrate based fertilisers (AN, CAN, ASN), are very popular nitrogen fertilisers worldwide, being easily available to plants since most crops take up nitrogen in nitrate form. One of the big challenges in the fertiliser finishing process is to achieve outstanding quality of the final product, in respect of environmental and low energy consumption requirements.

This paper covers SNC-Lavalin’s fluidised drum technology and its practical application in a project implemented at Sasol Nitro facilities, in South Africa, with a production capacity of 1,333 mtpd. Initially it describes the different granulation modes. The key parameters to be considered in the design and operating conditions of the granulation process will be described. The strengths and weaknesses of the main granulation processes are reviewed, along with their use for the different types of fertilisers. An industrial application case study is described, starting with the arguments retained by the client in favour of his technology choice.

This granulation technology consists of a cylindrical and horizontal drum, fitted with internal lifters, an internal fluidised table and a spraying header. The technology has been successfully applied in different plants and products around the world, the most recent being for Sasol Nitro, a large scale producer of ammonia and nitrogen fertilisers in South Africa. The main advantages of the CAN production technology are: high product quality, good roundness, high flexibility, low recycle rate, and a low caking tendency.