Discrete Simulation Model of Industrial Natural Gas Primary Reformer in Ammonia Production and Related Evaluation of the Catalyst Performance

Abstract

The catalytic steam reforming process of natural gas consumes up to approximately 60% of overall energy used in ammonia production. The optimization of the reforming catalyst performance can significantly improve the operation of the whole ammonia plant. An on-line model uses actual process parameters to optimize and reconcile the data of primary reforming products with possibility to predict the catalyst performance. The model uses a combination of commercial simulator and open-source code based on scripts and functions in form of m. file to calculate various physical properties of reacting gases. The optimization of steady-state flowsheet, based on real-time plant data from the distributed control system (DCS), is essential for the application of the model at the industrial level. The simplicity of the calculation method used by the model provides the fundamental basis for the industrial application in the frame of digitalization initiative. The principal aim of the optimization procedure is to change the working curve for methane regarding its equilibrium curve as well as methane outlet molar concentration. This is the critical process parameter in reforming catalyst operation. Industrial top fired primary reformer unit based on Kellogg Inc. technology design served for the validation of the model. Calculation procedure is used for continuous on-line evaluation of the most commercially available primary reformer catalysts. Based on the conducted evaluation, the model can indicate possible recommendations which can mitigate marginal performance and prolong reformer catalyst lifetime.