Keywords: Ammonium phosphate, Pipe reactor, NPK fertilizer, Blunger, Pre-neutraliser.

Summary:
UKF Fertilizers Limited operate three NPK plants at Ince in Cheshire in the UK. All are based on the Dorr Oliver blunger granulation process. As part of the original design a large reactor or pre-neutraliser is used for the manufacture of ammonium phosphate. This material is then mixed with liquid ammonium nitrate and pumped to the blunger as a mixed slurry.

The pre-neutraliser system has drawbacks particularly in terms of ammonia efficiency but also associated problems of slurry handling, process control and poor influence on the plant water balance.

This paper sets out the work done in improving the environmental performance of the plant over a period of eight years. The potential of the pipe reactor process, if it could be made to work, was quickly realised as providing a solution to the deficiencies whilst at the same time offering significant advantages in terms of simplicity of operation and control.

A number of plant trials were carried out spanning a total period of four and a half years but were more concentrated in the twelve months of 1982. The pipe reactor was proven during this time to be a viable alternative to the pre-neutraliser. The magnitude of the predicted advantages were aptly demonstrated and resulted in a recommendation to convert one NPK stream on a permanent basis.

The first pipe reactor stream has now been in operation for over eighteen months and a considerable amount of operating experience has been gained. Based on this experience, differences between the pipe reactor and pre-neutraliser processes are now even better understood and are highlighted in this paper together with some of the problems encountered and the additional benefits gained such as increased production rates.

A second stream has recently been converted and a program for future development instituted.

The paper concludes with a firm commitment towards the new pipe reactor process.

R J Milborne and D W Philip, UKF Fertilizers Ltd, Chester, UK.

20 Pages, 3 Figures, References, 5 Patent numbers.