Steam System Load Shedding Operational Analysis Using Dynamics Simulation of a Fertilizer Plant

Abstract

Steam system operation of a fertilizer plant can be complex due to high number of equipment, unavailable redundancy of steam suppliers and inter-dependency behaviour between steam users. The plant is subjected to partial or total shutdown whenever one boiler trips as both existing boilers are operating close to design capacity. Installation of an additional boiler will provide additional capacity margin in the event of one boiler trips. iCON(Symmetry) was used as the dynamic process simulation tool to establish proper management for load shedding activity with three boilers in operation. Model was developed for the integrated steam header, fuel gas and boiler feed water network. A detailed representation of the actual plant was achieved by incorporating plant hydraulics based on actual piping configurations, high fidelity equipment modelling, process control configurations, trip sequencing and operator manual interventions. This approach gives high accuracy in replicating the plant’s transient behaviour for load shedding case studies. The case studies prove the three boiler arrangement is able to sustain the plant’s continuous operation. An operational strategy was developed to minimize the impact of equipment trips. It is recommended to expand the model to include the process side to represent the actual plant behaviour with higher accuracy.