This paper will address the major considerations for the design of hydrogen plants based on the steam reforming process, which is the most commonly applied technology for hydrogen generation.
In refineries hydrogen is an essential utility to prepare clean transportation fuels. It is not only used for hydro treatment of finished products, but also for deeper hydro conversion of heavier and sourer crude fractions, for instance in hydrocrackers.
In most refineries a hydrogen plant is present that feds into a network that serves the various consumers. Often recovered hydrogen from off gas streams from hydro processing units or catalytic reformers is (re-)injected in the network.
Steam reforming is an endothermic process where hydrogen is generated by reaction of steam with hydrocarbons over a Ni-based catalyst. Usually the reactor is a direct fired multi-tube reactor, operating at temperatures around 850 - 920 0C, and pressures around 25-35 barg. Due to the high reaction temperatures, the heat recovery from flue gases and process gas is an essential part of the design of the hydrogen plant, and determines largely the overall efficiency of the plant.
Following topics are addressed:
Process design optimization
Hydrogen generation vs. hydrogen recovery
Furnace mechanical design (furnace types, design aspects of radiant and convection section, internals, supporting, piping manifolds, ducting, etc)
Furnace operations and safeguarding
Managing NOx emissions
Hydrogen production is an essential part of nowadays refinery set-ups. The design of the hydrogen plant shall be carefully optimized between technology licensor and end-user, as it is a large energy consumer, represents substantial investment cost and is deeply integrated into the refinery.