Abstract SYMPHOS 2011

RECENT IMPROVEMENT OF THE GRANULATOR PIPE REACTOR FOR THE
PRODUCTION OF GRANULAR AMMONIUM PHOSPHATES
Donal S. Tunks
Jacobs Engineering S.A., Casablanca, MOROCCO
PH-O-14
A Granulator Pipe Reactor can be used in the production of MAP/DAP to increase the production capacity while
substantially reducing the overall fuel consumption. This is accomplished through the mixing of ammonia and
phosphoric acid within the Granulator Pipe Reactor. From the high heat of reaction of this mixing, water is
evaporated prior to the drying step and this causes the significant drop in fuel consumption.
A recent development by Jacobs Engineering involves an elaborate continuous control scheme that maintains the
desired product quality while minimizing fuel consumption by utilizing on-line and at-line measurements.
Adding a Granulator Pipe Reactor to an existing facility is a relatively simple modification which and can pay itself
off in as little as 4 months.
fertilizers.
HOW TO INCREASE THE OVERALL OUTPUT OF PHOSPHORIC ACID
EVAPORATION LOOPS WHILE REDUCING THEIR TOTAL COSOWNERSHIP
Loic BERNARD
SGL Group Saint Martin d’Hères/FRANCE
PH-O-15
The phosphoric acid commercial concentration has been set at 54%. The different wet phosphoric acid processes
used around the world produce green acids with concentrations between 28 and 44% P2O5.thus meaning that
depending on the production process, the acid coming out from the reactor tanks must be concentrated in 1 to 3
evaporation stages. Each evaporation stage consists in an axial pump, a heat exchanger, a flash tank, a scrubber,
and condenser and a vacuum pump. Since industrial green phosphoric acid is extremely corrosive, rubber lined flash
tank and piping, a graphite heat exchanger and an axial pump in nickel-alloy are usually used.
In order to sustain a high productivity of the evaporation loop, the appropriateness between the axial pump
characteristics (curve) and the heat exchanger characteristics (tube diameter, length, cross section) is one of the
key to success. A high velocity in the heat exchanger means a better overall heat transfer coefficient and therefore
a larger output. It might also result in a lower fouling and therefore longer evaporation cycles between cleaning
cycles. However, throughout the complete evaporation cycle, the progressive fouling of the heat exchanger will
result in lower performances, higher pressure drops and therefore lower velocities thus leading to the further
reduction of the performances. The proper selection, design and sizing of the axial pump (construction design and
materials, characteristic curve) and of the graphite heat exchanger (graphite quality, cross section, tube length,
steam bustle, carbon fiber reinforced tubes, expansion system) associated with smooth operations (especially
during start-ups and shut-downs) guaranty a higher productivity, a better reliability, a longer equipment life time
and therefore overall a much higher output and a lower total cost of ownership.
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