A system to improve efficiency in refineries

We cut back our energy consumption
thanks to repHEN, a system for measuring
the level of fouling in heat exchangers


Fouling in heat exchangers is common in refineries across the world, pushing energy consumption up by between 2% and 3%. It is a highly significant “energy thief” that makes it difficult for the industry to reduce its CO2 emissions and has a direct impact on the world economy.

When crude oil arrives at a refinery, it is first heated up in a distillation furnace powered by natural gas. To prevent an excessive use of energy, the crude oil is pre-heated in the heat exchangers. However, the constant passing of fluids means that dirt gradually builds up in the equipment, reducing its efficiency little by little. This means that when the crude oil is transferred to the furnaces, more energy is needed to reach the required temperature.

At Repsol, we have spent years looking for ways to solve this global problem. In 2010, an internal tool was developed called repHEN, the Repsol Heat Exchanger Network. It is a model that simulates exchanger networks to analyze the condition they are in, compare performance in their current state and when “clean”, and calculate the amount of extra energy needed to heat the crude oil. 

The information generated helps technicians to design a more suitable cleaning strategy for the exchangers, as it tells them which exchanger is the dirtiest or what kind of cleaning technique would have the most impact on the network without having to wait for a general shutdown. 

And that is not the only advantage of this tool. Regularly analyzing the condition of the exchangers helps Repsol technicians take new measures to prevent fouling, such as redesigning equipment, installing bypasses to remove them from service and clean them while the unit is still operating, as well as adding new additives to the crude oil before it enters the network.