A model-based robust controller is designed for a packed bed methanation reactor. To accomplish
this objective, model uncertainty bounds are identified from experimental data. A physically
motivated methodology of "regions mapping" was developed to compute the uncertainty bounds
in the complex plane. This technique is compared to other existing nonparametric approaches
for a simple nonlinear system and is shown to produce a more accurate description of the model
uncertainty for the purpose of robust control design. This "regions-mapping" approach is then
applied to a fixed bed reactor and uncertainty bounds are computed. A robust controller with
a single adjustable parameter is designed for the reactor using internal model control (IMC)
theory. The computed uncertainty bounds are experimentally validated using the IMC controller
