Abstract:
In this project a solution to a problem at FFC-Ammonia-2 plant has been proposed. The plant is currently being operated at 20% overcapacity, due to which firing in primary reformer has been increased and this has led to excessively high flue gases temperature in the convection section (where heat of flue gases is used to heat various streams) of the primary reformer. This high temperature is harmful for heat exchanging coils and reduces their operational life and poses risks of equipment failure. At the moment extra steam is being injected into the secondary reformer air/steam stream. This steam absorbs the excess heat. This is a makeshift arrangement and our objective was to provide a viable alternative. After literature review, consideration of current industrial practices (especially in ammonia production facilities) and consultation with our both supervisors (industrial and university), incorporation of adiabatic pre-reformer has been proposed as it increases the plant capacity by 20-25% without additional energy cost. This modification has been made at various plants around the world and thus is a reliable technique. The proposed pre-reformer’s operating conditions have been specified. The volume of catalyst required has been calculated. Along with heat extraction scheme, a control loop to maintain the process at desired conditions has also been designed. After incorporating the proposed modification it has been concluded that protection steam would no longer be required. Apart from that feed stock flexibility and primary reformer operational flexibility would also be provided. Also the catalyst life of the primary reformer catalyst would be enhanced.
