Modelling and simulation of syngas unit in large scale direct reduction plant

The production of reducing gas is usually a bottleneck to capacity increase in direct reduction plants. Modelling and simulation of reducing gas production result in better design and operation of these plants. In the present work, a mathematical model is discussed that relates to a Midrex reformer, which is different from conventional steam reformers in some respects. Both process side and furnace side have been included in an integrated model. Simulation results have been tested against available data from an actual plant. The model predictions have been found to be reasonably accurate. The effects of three process variables, feed gas temperature, feed gas pressure and excess air, on reformer performance have been investigated. Simulation results confirm that an increment in feed gas temperature is the most effective method of increasing performance.