This work aims to optimise the operation of an evaporation network with shared resources in real time. The goal is minimising the resource utilisation (live steam and cooling water) while satisfying a set of operational constrains. Hence, problems of optimal load allocation of feeds to plants and cooling-water distribution among them arise. The work bases on plants surrogate models, experimentally obtained, and analyses different formulation alternatives of the optimisation from the practical point of view: centralised vs distributed approaches. In particular for the distributed approach, we propose a problem decomposition which allows us to solve the problem in two iterative ways: 1) as two independent optimisations or 2) via price-coordination schemes.