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Customer: Fertilizer Plant.
Location: Southern Coastal India.
Tower Name: High Pressure Regenerator.
Tower Diameter: 3620 mm Packed bed column.
Mass Transfer Equipment:Flash Feed Gallery.
History:
Customer operates one of the largest integrated Ammonia-Urea Fertilizer plant in
India, comprising 900TPD Ammonia & 1500TPD Urea facility.
Process Overview:
Ammonia and Urea production unit generate their H2, N2 & CO2 feeds through
a common reformer.
Outlet gases from the reformer are passed thru the absorber, where Hydrogen along
with other light gases are separated while the CO2 is removed through absorption
in the solution. Hydrogen & other light gases along with slipped CO2 from the top of
the absorber are passed to the methanation section as a feed. The methanator
converts the residual CO2 to methane to increase the catalyst life of the
ammonia reactor.
The rich solution from the absorber is then
stripped in the regenerator and the CO2
gas used to produce Urea. The lean solution from the regenerator bottom is sent back to the absorber.
Customer Requirements:
Customer was facing serious problem of liquid carry over in the CO2 stream from
the regenerator top which was fouling the downstream heat exchangers.
Problem analysis:
After studying the system for operation at an increased capacity it was noted that
- Absorber was functioning normally.
- Regenerator column was experiencing severe liquid carryover
along with the CO2.
- Feed inlet nozzle was directing the inlet mixed phase feed onto the clear
liquid residing on the Flash Feed Gallery (FFG) deck thereby creating turbulence and liquid carryover problem.
Solutions provided:
After studying entire equipments in CO2 removal section & further detail hydraulic
check at increased capacity, following was recommended
- Option1 - Increase the FFC vertical wall height (that would entail hot work).
- Option 2 - decrease the open area thereby increasing the FFC deck area.
- Modify the inlet feed arrangement to facilitate lateral release of liquid along
the column periphery / wall & then onto the FFG.
Customer accepted option 2 along with modification of inlet feed arrangement.
Accordingly the equipment was mechanically designed, manufactured and installed
without involving any hot work to the column.
Results achieved:
The problem of carryover has been solved. The CO2 removal section now runs at
increased load of 1350 MTPD. |
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