Low Recycle NPK Granulation – Design and Practical Aspects

Synopsis.

Some aspects of the design and operation of two SAI compound fertiliser granulation plants are reviewed – firstly the modified SAI-R Granulation Plant at Leith producing ammonium nitrate based fertilisers and secondly the recently constructed Solid Feed Granulation Plant at Aberdeen manufacturing fertilisers based on ammonium phosphate intermediates. In the original SAI-R Granulation process phosphoric acid, nitric acid and ammonia together with potash were fed to SAI-R granulators and the plant at Leith operated in this manner for several years. It became necessary, however, to increase the output from this plant and the acid and ammonia feeds to the granulators have been replaced by low moisture ammonium phosphate/nitrate liquor. The Aberdeen Granulation Plant is required to produce a wide range of slightly lower analysis formulations including horticultural fertilisers and the design is based on the use of solid raw materials and fertiliser intermediates.

The paper concludes with a review of certain aspects of fertiliser plant design, safety, operation and maintenance.

G B Whyte, C.Eng, MIMechE., Scottish Agricultural Industries Ltd, Edinburgh, UK.

50 pages, 11 figures, 17 references.