5 Flashcards
_____ is a term used to describe all different processes in which hydrocarbon reacts with hydrogen. It includes hydrotreating, hydrocracking and hydrogenation
Hydroconversion
_____ is used to describe the process of the removal of sulfur, nitrogen and metal impurities in the feedstock by hydrogen in the presence of a catalyst.
Hydrotreating
_____ is the process of catalytic cracking of feedstock to products with lower boiling points by reacting them with hydrogen.
Hydrocracking
_____ is used when aromatics are saturated by hydrogen to the corresponding naphthenes. (double bond to single bond)
Hydrogenation
_____ units are needed in
the refinery to clean streams from
material such as sulfur, nitrogen or
metals harmful to the catalysts.
• also used to transform unsaturated compounds to the corresponding saturated hydrocarbons.
Hydrotreating
Chemistry of Hydrotreating:
• Desulphurization
• Denitrogenation
• Deoxidation
• Hydrogenation of Chlorides
• Hydrogenation of Olefins
• Hydrogenation of Aromatics
The liquid feed is mixed with hydrogen and fed into a heater and the
mixture is brought to the reaction temperature in a furnace and then fed into a fixed bed catalytic reactor.
• The effluent is cooled and hydrogen-rich gas is separated using a high-pressure separator. Before the hydrogen is recycled, hydrogen sulfide can be removed using an amine scrubber.
• Some of the recycle gas is also purged to prevent the accumulation of light hydrocarbons (C1–C4) and to control hydrogen partial pressure. The liquid effluent for the reactor is introduced to a fractionator for product separation
Hydrotreating General Process
The _____ used in hydrocracking is a bifunctional one. It is composed of a metallic part, which promotes hydrogenation, and an acid part, which promotes cracking.
catalyst
_____ is a catalytic hydrogenation process in which high
molecular weight feedstocks are converted and hydrogenated to lower
molecular weight products.
Hydrocracking
_____ is the addition of hydrogen to an alkene (unsaturated) which results in an alkane (saturated).
Hydrogenation
_____ will break bonds, and the resulting unsaturated products are consequently hydrogenated into stable compounds.
Cracking
Hydrocarbon chemistry:
• Alkane hydrocarbon
• Hydrodealkylation
• Ring opening
• Hydroisomerization
• Polynuclear aromatics hydrocracking
In commercial hydrocrackers, a conversion of 40–80% of the feed can be achieved. However, if high conversion is required the product from the bottom of the distillation tower is recycled back to the reactor for complete conversion. What process is this?
Hydrocracking Process
The _____ process combines propenes and butenes to produce higher olefins with high-octane numbers for the gasoline pool.
polymerization
The _____ process combines light iso-paraffins, most commonly isobutane, with C3–C4 olefins, to produce a mixture of higher molecular weight iso-paraffins as a high-octane number blending component for the gasoline pool.
alkylation
Alkylation is catalyzed by what strong acid?
either sulfuric (H2SO4) or hydrofluoric(HF)
In the absence of catalysts, alkylation between isobutane and olefin must be run under severe conditions such as _____
500 C and 2940–7080 psia
In the presence of an acid catalyst, the reaction temperature will be lower than
50 C, and the pressure will be lower than 441 psia
The feed stream is then passed through a reactor with a 1._____, generally a solid catalyst or _____, where an exothermic polymeric reaction occurs.
- phosphorus catalyst
- liquid phosphoric acid
The main purpose of _____ is to find the best way of mixing
different intermediate products available from the refinery and some additives in order to adjust the product specifications.
product blending
The final quality of the finished products is always checked by _____ before market distribution.
laboratory tests
_____ are tested for octane number
Gasolines
_____ are tested for flash point and volatility
Kerosene
____ are tested for
diesel index, flash point, pour point and viscosity.
Gas oils
