Presentation on theme: "50% CAPACITY INCREASE OF AN – 72 PLANT UTILIZING THE ORIGINAL PRILLING TOWER MAXIM FERD OAO GIAP, MOSCOW, RUSSIA VASIL GRANCHAROV NEOCHIM PLC, DIMITROVGRAD,"— Presentation transcript:
50% CAPACITY INCREASE OF AN – 72 PLANT UTILIZING THE ORIGINAL PRILLING TOWER MAXIM FERD OAO GIAP, MOSCOW, RUSSIA VASIL GRANCHAROV NEOCHIM PLC, DIMITROVGRAD, BULGARIA
Features of a typical AN – 72 plant: Design capacity 1360 MT/Day One - stage neutralization in reactors operating under atmospheric pressure. One - stage evaporation under atmospheric pressure in air current.
Ammonium nitrate melt is pumped from the ground level to the top of the prilling tower. Steel - made prilling tower with a rectangular cross - section is employed. The fluidized bed cooler is placed outside the prilling tower.
Air coming from the evaporator and the prilling tower, together with the steam exiting the secondary steam recovery system, undergo scrubber treatment prior to being vented to the atmosphere.
There are a total of 19 AN – 72 plants built in the period 1977 – 1987, all of them in the FSU countries and a single one outside the FSU, built in Dimitrovgrad, Bulgaria, and operated by Neochim PLC.
The sole significant improvement of the AN - 72 plants until nowadays, has been the addition of filter packs as a final stage in the scrubbers at the top of the prilling tower.
Engineering decisions for the prilling tower include: Replacement of the three fans supplying air to Replacement of the three fans supplying air to the tower’s bottom and the six exhaust fans at the top of the tower by new ones with total capacity 30 % greater than this of the original ones. Replacement of the original 3 static granulators by 2 vibro - granulators with a rotating basket, aiming at a narrower size distribution and to a greater - extent elimination of dust carryout expected as a result of the increased air velocity in the tower’s cross - section.
Engineering decisions for the prilling tower include: Increase of the filter surface of the six Increase of the filter surface of the six scrubbers at the tower’s top by 10 % and use scrubbers at the tower’s top by 10 % and use of three - layer packs of filtrating material with of three - layer packs of filtrating material with different layer characteristics. different layer characteristics. Washing of the frontal filter pack’s surface with Washing of the frontal filter pack’s surface with finely - spread secondary steam condensate. finely - spread secondary steam condensate.
Engineering decisions for the prilling tower include: Introduction of preliminary purification of the Introduction of preliminary purification of the secondary steam and air from the evaporators in a separate scrubber prior to the steam air stream being fed to the tower’s scrubbers. Introduction of additional ammonia air cooling Introduction of additional ammonia air cooling at the second stage of the fluidized bed cooler.
Engineering decisions for the “wet” part Engineering decisions for the “wet” part include: include: Addition of a new neutralizer identical to the Addition of a new neutralizer identical to the existing ones, an evaporator with modified design, and of all necessary equipment for their operation.
Project Milestones Project Milestones June 1 st 2007 First earth moved June 16 th 2008 First neutralization in the “new” wet part carried out July1 st 2008 Plant at full swing
Comparison of the plant’s major operational parameters before and after the revamp. ItemBefore revampAfter revamp Ammonia214.0 Kg/MT211.5 Kg/MT Nitric acid780.0 Kg/ MT777.3 Kg/ MT 17 Bar Steam0.236 T/MT0.181 T/MT Power20 kW/MT22.9 kW/ MT AN emission exit towerLess than 70Mg/NM312.8 Mg/NM3 Ammonia emission exit towerLess than 20 Mg/Nm35.4 Mg NM3 Granulometry73% between 2-3 mm90% between 2-3 mm 95 % between 1-4 mm99 % between 1-4 mm Maximum achieved capacity1550 MT/Day2350 MT/Day
Better consumption figures were achieved The improved granulometry allowed bypassing the originally installed sieve section and thus discontinuing reprocessing of off spec material. Emission levels for both AN and ammonia were reduced to BAT levels. Capacity increase of more than 70 %, based on name plate, and more than 50 %, based on best log, was achieved.
50 % CAPACITY INCREASE Proven now commercially, is the possibility to increase the production capacity of a typical AN – 72 plant, from 1360 MT/Day(name plate) to 2350 MT/Day utilizing the existing prilling tower and keeping the AN and ammonia emissions at BAT levels. The revamp leads to an Improvement of both Ammonia and Nitric acid consumption figures. Better product granulometry is also achieved. Capex for such a revamp is significantly lower than that needed for the addition of the same incremental capacity using the existing AN – 72 design or the known granulation process. CONCLUSIONS