Patented concept to hugely increase the capacity of an existing ammonia plant.
Plant capacity can be increased up to 100% of the present plant production.
Energy saving higher than 0.5Gcal/MTNH3
The philosophy originally developed for the super revamp is based on two main key points:
- Front-end debottlenecking with significant reduction of specific gas flow, by reduction of the S/C ratio and removal of N2, allowing to increase the net NG flow without significant increase in section pressure drop;
- Inert-free synloop operation, which allow increasing the per-pass conversion and therefore the production rate with limited increase in the circulation flow.
The reduction of the steam/carbon ratio, is made possible by the introduction of the pre-reformer, and allows maintaining the overall mass flow rate in reforming section, despite a plant capacity increase of more than (usually) 35÷40%.
Downstream the primary reformer, the existing secondary reformer is modified to ATR by replacing air feed with pure O2 feed. The removal of N2 from all the following sections generates a reduction in specific gas flow by more than 40% with respect to current operation, which together with the lower S/C makes it possible to significantly increase the feed flow without affecting the overall pressure drop.
Upstream the HTS a quench with water allows reducing of the temperature and achieving a proper S/CO ratio at the shift section inlet. The existing high temperature and low temperature shift converter are revamped with axial-radial internals in order to treat the increased gas flow rate.
To recover the increased amount of CO2, the CO2 removal section is revamped (addition of an upstream pre-wash section could be required); after methanation, final gas purification is performed in the a new
LNW where all the inerts are removed from the process gas generating a virtually inert-free hydrogen stream which can be directly fed to the syngas compressor.
Inside the synthesis loop the main converter is revamped by installation of an additional ammonia converter to enhance the ammonia synthesis. No modifications are envisaged in refrigeration sections.
The plant capacity can be increased 100% compared to the current plant daily throughput.