What is spent hydrotreating catalyst?

What is spent hydrotreating catalyst?

Abstract. An industrial waste spent residue hydroprocessing catalyst, contains high levels of metals and carbon, which decreases catalytic activity and forces the refiner to replace the catalyst.

What is spent catalyst?

Nicolas Stockreiter. Catalysts gradually lose their catalytic activity, usually through structural changes, poisoning, overheating or the deposition of extraneous material such as coke. A catalyst is “spent” when it no longer exhibits the necessary activity or specificity required by the user.

How do you treat a spent catalyst?

Several alternative methods such as disposal in landfills, reclamation of metals, regeneration/rejuvenation and reuse, and utilization as raw materials to produce other useful products are available to the refiners to deal with the spent catalyst problem5,6.

What is hydroprocessing catalysts?

Hydroprocessing is the name given to a series of chemical reactions that take place as part of oil refining, and include hydrogenation, hydrocracking and hydrotreating. These catalysts provide a wide range of well-proven products for a broad range of HDS and HDN duties. …

What is Hydrorefining?

The first hydrorefining stage effluent comprises a partially desulfurized naphtha product, and a gaseous product including hydrogen sulfide, light hydrocarbon gases such as C 1 to C 3, hydrogen, etc.

Is Spent catalyst hazardous waste?

Due to their toxic nature, spent hydroprocessing catalysts have been branded as hazardous wastes, and the refiners are experiencing pressure from environmental authorities to handle them safely.

Which catalyst is used in cracking?

Catalytic cracking uses a temperature of approximately 550°C and a catalyst known as a zeolite which contains aluminium oxide and silicon oxide.

Which catalyst is used in FCC?

The catalyst NiMoP/HY-Al2O3 (spent FCC catalyst) stands out due to its high hydrodesulfurization activity attributable to the ease of impregnation of metals over FCC catalyst and the accessibility of the components of the LCO to the hierarchical porous structure.

Are catalysts considered waste?

Once catalysts completes their life cycle they will be withdrawn from the process, at this stage, catalysts are considered “spent” and the heavy metals, coke, and other poisonous elements make them as hazardous waste.

In which type of cracking catalyst is more with heavy oil?

Typically, using zeolite-based catalysts in hydrocracking results in greater cracking activity owing to its greater acidity. In addition, the use of zeolite-based catalyst improves thermal or hydrothermal stability and resistance to nitrogen/sulfur compounds.

How is hydrotreating done?

Hydrogen processes, commonly known as hydrotreating, are the most common processes for removing sulfur and nitrogen impurities. The oil is combined with high-purity hydrogen, vapourized, and then passed over a catalyst such as tungsten, nickel, or a mixture of cobalt and molybdenum oxides supported on an alumina base.

What kind of waste is spent hydroprocessing catalyst?

Spent hydroprocessing catalysts have been classified as hazardous wastes by the environmental protection agency (EPA) in the USA.

Where do spent catalysts go in a refinery?

In many refineries, the spent catalysts discarded from hydroprocessing units form a major part of these solid wastes. Disposal of spent hydroprocessing catalysts requires compliance with stringent environmental regulations because of their hazardous nature and toxic chemicals content.

How much spent hydrotreating catalyst is produced each year?

The total quantity of spent hydrotreating catalysts generated worldwide is in the range of 150,000–170,000 t/year ( Dufresne, 2007 ). Disposal of spent catalysts requires compliance with stringent environmental regulations.

How are spent catalyst wastes bad for the environment?

Metals such as Co, Ni and V that are present in spent hydroprocessing catalysts are included in the list of potentially hazardous wastes published by the Environment Canada. These metals can be leached by water after disposal and pollute the environment.