Gujarat Narmada Valley Fertilizers Co. Ltd. (GNFC) is one of the leading fertilizer companies in India as well as in the world for manufacturing various fertilizers such as ammonia, urea, ammonium nitro phosphate and calcium ammonium nitrate. The urea plant of GNFC has the capacity to produce 1800 MTPD based on ammonia stripping technology of Snamprogetti, Italy. To sustain the competitive edge in the market, it was decided to enhance the capacity of the plant. This was to be carried out by studying all operational and design parameters and identifying the limiting factors for the plant load as well as efficiency and productivity of the plant. Accordingly, the limiting equipment and machineries were identified as bottlenecks and various improvements have been carried out to upgrade the plant capacity to 2350 MTPD. These improvements include:
1. Replacing the conventional sieve trays of urea plant reactor by high efficiency trays.
2. Modernization of high pressure ammonia pumps.
3. CO2 enhancement scheme
4. Increasing CO2 machine throughput by various measures.
5. Replacement of stripper (high pressure decomposer) by higher capacity, improved design stripper.
6. Replacement of high pressure carbamate condenser by higher capacity, new improved design carbamate condenser.
7. Identification of metal deposits / corrosion products on the tubes of medium pressure and low pressure decomposers and suitable actions taken to eliminate the adverse effects.
8. Changing the material of construction of several equipment by technically superior material of construction.
9. Increasing the capacity and efficiency of various pumps by installing improved design impellers, other internals as well as higher capacity and upgraded electrical drives (motors).
10. A breakthrough in identification of reactor liner leakage through modernization of reactor weephole monitoring system.
11. Replacing the trays of medium pressure absorber and waste water distillation tower by superior designed trays.
12. Modernization of CO2 compressor and turbine.
13. Modernization of high pressure carbamate pumps.
By implementing these improvements, it is possible to operate the plant at very high level of production with minimum downtime. The implementation of modernization concepts and debottlenecking measures have helped in increasing the capacity of the plant and also in improving the stability as well as efficiency and productivity of the plant. The reliability of GNFC Urea plant has taken a sharp jump after implementation of all these measures.