50% CAPACITY 50% CAPACITY INCREASE INCREASE OF AN – 72 OF AN – 72

PLANTPLANT UTILIZING THE UTILIZING THE

ORIGINAL ORIGINAL PRILLING PRILLING TOWERTOWER

MAXIM FERDMAXIM FERDOAO GIAP, MOSCOW, RUSSIAOAO GIAP, MOSCOW, RUSSIA

VASIL GRANCHAROVVASIL GRANCHAROVNEOCHIM PLC, DIMITROVGRAD, BULGARIANEOCHIM PLC, DIMITROVGRAD, BULGARIA

Features of a typical AN – 72 plantFeatures of a typical AN – 72 plant: :

Design capacity 1360 MT/DayDesign capacity 1360 MT/Day

One - stage neutralization in reactors operating under One - stage neutralization in reactors operating under atmospheric pressure. atmospheric pressure.

One - stage evaporation under atmospheric pressure One - stage evaporation under atmospheric pressure in air currentin air current..

Ammonium nitrate melt is pumped from theAmmonium nitrate melt is pumped from the

ground level to the top of the prilling tower.ground level to the top of the prilling tower.

Steel - made prilling tower with a rectangularSteel - made prilling tower with a rectangular

cross - section is employed. cross - section is employed.

The fluidized bed cooler is placed outside theThe fluidized bed cooler is placed outside the

prilling tower. prilling tower.

Air coming from the evaporator and theAir coming from the evaporator and the

prilling tower, together with the steamprilling tower, together with the steam

exiting the secondary steam recoveryexiting the secondary steam recovery

system, undergo scrubber treatmentsystem, undergo scrubber treatment

prior to being vented to the atmosphere. prior to being vented to the atmosphere.

There are a total of 19 AN – 72 plantsThere are a total of 19 AN – 72 plants

built in the period 1977 – 1987, all ofbuilt in the period 1977 – 1987, all of

them in the FSU countries and a singlethem in the FSU countries and a single

one outside the FSU, built inone outside the FSU, built in

Dimitrovgrad, Bulgaria, and operated byDimitrovgrad, Bulgaria, and operated by

Neochim PLC. Neochim PLC.

The sole significantThe sole significant

improvement of the AN - 72improvement of the AN - 72

plants until nowadays, hasplants until nowadays, has

been the addition of filter been the addition of filter

packs as a final stage in thepacks as a final stage in the

scrubbers at the top of thescrubbers at the top of the

prilling tower. prilling tower.

Engineering decisions for the prilling tower include: Engineering decisions for the prilling tower include:

Replacement of the three fans supplying air toReplacement of the three fans supplying air to

the tower’s bottom and the six exhaust fans atthe tower’s bottom and the six exhaust fans at

the top of the tower by new ones with totalthe top of the tower by new ones with total

capacity 30 % greater than this of the originalcapacity 30 % greater than this of the original

ones. ones.

Replacement of the original 3 static granulatorsReplacement of the original 3 static granulators

by 2 vibro - granulators with a rotating basket,by 2 vibro - granulators with a rotating basket,

aiming at a narrower size distribution and to aaiming at a narrower size distribution and to a

greater - extent elimination of dust carryoutgreater - extent elimination of dust carryout

expected as a result of the increased airexpected as a result of the increased air

velocity in the tower’s cross - section. velocity in the tower’s cross - section.

Engineering decisions for the prilling towerEngineering decisions for the prilling tower

include: include:

Increase of the filter surface of the sixIncrease of the filter surface of the six

scrubbers at the tower’s top by 10 % and usescrubbers at the tower’s top by 10 % and use

of three - layer packs of filtrating material withof three - layer packs of filtrating material with

different layer characteristics. different layer characteristics.

Washing of the frontal filter pack’s surface withWashing of the frontal filter pack’s surface with

finely - spread secondary steam condensate . finely - spread secondary steam condensate .

Engineering decisions for the prilling towerEngineering decisions for the prilling tower

include: include:

Introduction of preliminary purification of theIntroduction of preliminary purification of the

secondary steam and air from the evaporators secondary steam and air from the evaporators

in a separate scrubber prior to the steam airin a separate scrubber prior to the steam air

stream being fed to the tower’s scrubbers. stream being fed to the tower’s scrubbers.

Introduction of additional ammonia air coolingIntroduction of additional ammonia air cooling

at the second stage of the fluidized bed cooler. at the second stage of the fluidized bed cooler.

Engineering decisions for the “wet” partEngineering decisions for the “wet” part

include:include:

Addition of a new neutralizer identical to theAddition of a new neutralizer identical to the

existing ones, an evaporator with modifiedexisting ones, an evaporator with modified

design, and of all necessary equipment for theirdesign, and of all necessary equipment for their

operation. operation.

Project MilestonesProject Milestones

Comparison of the plant’s major operational parameters beforeComparison of the plant’s major operational parameters before

and after the revamp.and after the revamp.

Item Before revamp After revampAmmonia 214.0 Kg/MT 211.5 Kg/MT

Nitric acid 780.0 Kg/ MT 777.3 Kg/ MT

17 Bar Steam 0.236 T/MT 0.181 T/MT

Power 20 kW/MT 22.9 kW/ MT

AN emission exit tower Less than 70Mg/NM3 12.8 Mg/NM3

Ammonia emission exit tower Less than 20 Mg/Nm3 5.4 Mg NM3

Granulometry 73% between 2-3 mm 90% between 2-3 mm

95 % between 1-4 mm 99 % between 1-4 mm

Maximum achieved capacity 1550 MT/Day 2350 MT/Day

50 % CAPACITY 50 % CAPACITY INCREASEINCREASE

CONCLU

SIONS

СПАСИБО МАКСИМ ФЕРД !СПАСИБО МАКСИМ ФЕРД !СПАСИБО “ГИАП “ !СПАСИБО “ГИАП “ !

THANK YOU ! THANK YOU !