This paper proposes and compares different steady-state models for the methanol synthesis fixed-bed reactor. The main goal is to indicate the pros and cons of these alternative models, to highlight their peculiarities in providing accurate and reliable estimations, and to warn the reader about possible risks involved in certain modeling assumptions. The Lurgi-type shell and tube boiler-reactor mathematical modeling is also laid out, before more complex issues and research, such as dynamic simulation or PDE-based predictive control, are broached. (C) 2010 Elsevier Ltd. All rights reserved.