Granulation and Prilling

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Granulation and Prilling

NIIK offers several main methods of obtaining a commercial grade of urea. These are granulation in a fluid bed, prilling in towers, and granulation in drum granulators. We continue to work on improving the manufacturability and ease of use of all methods.


FLUIDISED BED GRANULATION PROCESS:


NIIK is continuously improving the granulation process. Equipment parts and designs are being improved and tested on the test facility. Further patents are being prepared. We offer our customers our new development - urea granulation plant with the capacity of 3 000 mtpd.


NIIK JSC has patented a unit and method for obtaining granulated product in a fluid bed.


Fluid bed granulation technology is the granulation of urea by spraying a thin layer of liquid urea melt with nozzles onto solid particles of urea seed ("retour") in a fluidised state. While in the granulation zone, each granule is repeatedly covered with a thin layer of urea melt.

The size increase is uniform for all granules and occurs gradually during the time in the granulation zone, resulting in a uniform shape and high quality of the finished product.

Fluidised bed granulation plants have a wide range of capacities (1500 - 3000 mtpd).


Distinctive features of the fluidi bed granulation unit designed by NIIK are:


Urea prilling process

NIIK has been working on development of urea technology and improvement of urea prilling section since 1960s.  

Based on known-how and expertise NIIK developed the following methods of prilling process improvement:

A modern prilling tower of NIIK design is a structure with a height of up to 100 metres (excluding process pipes) and an inner diameter of the tower shaft from 12 to 21 metres, depending on the required capacity (from 600 to 3000 mtpd and more), simple and reliable in operation.

Advantages of a prilling tower:

  1. Zero waste: no agglomerates and defected product for recycle and consequently no classifying, crushing and recycle of the defected product: no solid wastes and effluents. For prilling tower having steel and concrete body: equipment and steel structures can be easily disassembled and utilized, resold and relocated.
  2. High process efficiency: minimal amount of equipment, including dynamic equipment, as the technology has fewer process stages; simplicity and reliability of operation - there is no need for constant washing and maintenance of technological, especially dynamic, equipment, as a result of which no repair and maintenance staff is required.

  3. Resource saving:

    • Lower steam and electricity consumption for process needs compared to a granulation plant;
    • multiple less formaldehyde additive in the finished product or no formaldehyde additive at the customer's request;
    • no refrigerant supply or additional cooling systems for the finished product are required.
  4. Cost-effective installation: technology and resource efficiency result in minimal operating, repair and maintenance costs.
  5. Environmental friendliness: minimal emissions of harmful substances into the atmosphere with the air leaving the tower (ammonia not more than 50 mg/nm3, urea not more than 30 mg/nm3 without acid recovery).

  6. Product quality:

    • resistant to mechanical effects during transport and storage;
    • 100% crumbliness;
    • monodispersity;
    • optimal size and spherical shape of prills, which is very important for dry tucosmixing, uniformity of soil application and farming.
  7. Capacities range: 600-3000 TPD of the final product.
  8. Efficiency of investment: CAPEX of a prilling tower construction is lower than CAPEX for a granulation unit.

HIGH SPEED DRUM GRANULATOR UNIT

High speed drum granulator unit (HSDG) is applied for production of granulated fertilizers by dispersing a solution, melt or a suspension on a loose material curtain in a moving air medium in a rotating drum provided with internal blades. The difference of HSDG from other existing drum granulators consists in increase of rotation frequency from 6-12 to 28-35 rpm. This allows to create granules curtain covering the entire cross section of the drum and to intensify the process. Unit filling factor increases from 15% to 75%. Rate of recycling decreases. The finished product is characterized by lower humidity and higher strength.

HSDG unit technical and economic performance

Parameter Value
Capacity, t/h 10
Air, м3/t 1300-2000*
Water, 3/t 0-15*
Electric energy, kWh*/t 35
Moisture removal from 1 m3, kg/h 30
Length, m 10,6
Diameter, m 2,5
*- consumption depends on the type of granulated product.


HSDG unit technical and economic advantages

The range of produced products



The range of complex fertilizers produced by high speed drum granulator unit is very broad. NIIK has not carried out special technical studies aimed at HSDG produced granulated fertilizers diversification. Upon the customer’s request the company may perform experiments in order to explore the possibility of production of a certain fertilizer type by HSDG.




Product quality parameters

Parameter Value
Main fraction, mm 3-5*
Main fraction content, % wt min 95
Product temperature, 0С oС 45±5

* - may be changed (upon customer’s request).
 

HSDG unit application

Services provided by NIIK for prilling towers