Hydrogen Production Plant Overview – The early use of H2 was in naphtha Hydrotreating, as feed pretreatment for catalytic reforming which in turn is a process for H2 production.
There has been a continual increase in refinery hydrogen demand over the last several years. This is a result of two main reasons impacting the refining industry, environmental regulations and feedstock shortage. Such reasons are pushing the industry to shift from “distillation” to conversion of oil. It is also important to note that the changes in the product slate requirements in some parts of the world, from more gasoline to more diesel has also impacted the oil refining industry. Refiners are left with an oversupply of heavy high sulfur oil and in order to make lighter, cleaner and more salable products, they need to add hydrogen or remove/reject carbon.
Hydrogen Production Plant Overview | Energy Efficiency Guidelines for Oil Refining
As hydrogen use has become more widespread in refineries, H2 production has moved from the status of a high-tech operation to an integral part of most refineries. Such move in oil industry has become necessary by the increase in Hydrotreating and hydrocracking processes.
H2 has been produced in catalytic reforming, as a by-product of the production of the high octane aromatics compounds used in gasoline. Changes in this process have had a large impact on the refinery hydrogen balance. As reforming has changed from fixed bed to continuous catalyst regeneration CCR process, hydrogen production per barrel of reformate has increased. However, recent changes in gasoline composition, due to environmental concerns, have tended to reduce hydrogen production. Anyway, by-product H2 production most of the time is not adequate and hence, H2 has been manufactured using steam reforming, which is the most widely used one, and partial oxidation processes.
In steam reforming process, light hydrocarbon such as methane is reacted with steam to form H2 in a furnace at approximately 1600ºF. The reaction is highly endothermic (227,000 J/g mole).
Hydrogen plants in oil refining sites are energy users and generators. The energy targeting step includes drawing a boundary around the facility.
Heat in and out, directly, and/or indirectly through steam consumption and/or generation, water production and/or generation, power consumption and/or generation are among the plant’s boundary are all identified.
Heat integration between feed and product is common in such facilities. Heat integration between reaction sections are highly recommended to achieve lower energy consummation targets. Steam reformer is an excellent steam generator unit and its optimization shall be included in the plant-wide combined heat and power system (CHP) optimization efforts.
Pinch technology application for standalone hydrogen plant/steam reformer will be included in later versions of this manual.