Abstract: A method is provided for controlling a multi-stage process. The process comprises multiple first stage processes for producing an intermediate product from a feed, and multiple further stage processes for producing an end-product from the intermediate products. The first stage processes comprise multiple intermediate processes and the further stage processes comprise multiple end processes for producing the end product. An intermediate controller controls the first stage processes in response to one or more product properties of the end product EP and a further controller FC controls the further stage processes in response to the product properties of the intermediate product. The multi-stage process further comprises the step of assigning process values to each of the end processes and the intermediate processes. The intermediate controller IC controls operation of the intermediate processes to optimize the overall process value for producing the end product.

Abstract: The present invention is directed to innovative and unique mathematical models that capture key constraints, process kinetics and control structures such that a wide envelope of hydrogen gas and associated light gas supply, distribution and use can be modeled. The present invention is also directed to a real time optimization (RTO) computer application for effective optimization of hydrogen and associated light gas supply and distribution and, thereby, consumption, in a refinery that employs said models and solves an objective function, as well as to a method and refinery using the same. The objective function can be an economic objective function such as the minimization of cost for hydrogen supply and distribution or the maximization of profit based on a valuation of products made by hydrogen consumers in the hydrogen system minus the corresponding cost of the hydrogen supply and distribution.