Which catalyst is used in hydrotreating?
However, metal oxides, that is, alumina-supported metal sulfides are, by far, the most utilized catalysts for hydrotreating. They possess a lower cost, higher resistance to impurities typically present in waste feedstock and allow co-hydroprocessing of plant lipids and petroleum feeds in existing refinery facilities.
What is Sulfiding of catalyst?
Catalyst sulfiding involves the following chemical reactions: The Sulfiding Process. The sulfiding process involves passing feed spiked with a sulfiding agent over the catalyst bed in a carefully controlled procedure that includes several temperature holds.
Why catalyst sulfiding is done?
Presulfiding is often done to enhance activity as in hydrodesulfurization or control hyperactivity as with fresh or regenerated catalyst used for hydrocracking. Under certain operating conditions, such as hydrodealkylation, presulfiding selectively poisons the active sites that may degrade benzene.
Which reactor is mostly used in hydrotreating process?
A three-phase ebullated bed reactor used for hydrotreating consists of a liquid phase containing the petroleum reactants, an inlet gas phase of hydrogen with an outlet gas phase that contains the clean, lower molecular weight organic products, and the solid phase catalysts.
What is distillate hydrotreating?
The distillate hydrotreater is a category of hydrotreaters that treats distillate streams from atmospheric distillation and from conversion units to reduce their sulfur content and to improve their properties for blending into diesel.
What does Sulfiding mean?
Divalent sulfur
sul·fide. (sŭl′fīd′) Divalent sulfur, or a compound of divalent sulfur with an electropositive element or group, especially a binary compound of sulfur with a metal.
What is hydrotreating process in petroleum refinery?
Hydrotreating or hydrodesulfurization refers to a set of operations that remove sulfur and other impurities (Figure 1). During hydrotreating, crude oil cuts are selectively reacted with hydrogen in the presence of a catalyst at relatively high temperatures and moderate pressures.
What kind of sulfiding agent is used in hydrotreating catalyst?
As the feed and sulfur spiking agent are heated in the presence of hydrogen and the catalyst, the sulfur compound will readily decompose to form the H 2 S required to complete the sulfiding reactions. The sulfiding agents most commonly used by refiners today are dimethyl disulfide (DMDS) and tertiary-butyl polysulfide (TBPS).
What happens to the catalyst in the hydrotreating process?
If not separated out, these impurities can cause pressure drop in the catalyst bed, catalyst deactivation, and corrosion. The hydrotreating process involves mixing hydrogen with sour hydrocarbon feed inside a reactor filled with Cobalt/Molybdenum (CoMo) or Nickel/Molybdenum (NiMo) catalysts.
What do you need to know about catalyst sulfiding?
Catalyst sulfiding (aka “presulfiding”) is a critical step to ensure that hydrotreating catalysts perform as designed after startup.
Why is the sulfiding process important for hydroprocessing?
Proper sulfiding of hydrotreating catalysts is critical for obtaining optimum activity from a hydroprocessing unit. The sulfiding process must be carefully monitored to avoid reduction of the metal oxides prior to the formation of the active sulfides and to ensure that the active metal sites are properly and completely formed.