Why is cracking a necessary part of the refinement of crude oil?

Why is cracking a necessary part of the refinement of crude oil?

Cracking is important for two main reasons: It helps to match the supply of fractions with the demand for them. The supply is how much of a fraction an oil refinery produces. Since cracking converts larger hydrocarbons into smaller hydrocarbons, the supply of fuels is improved.

What is purpose of cracking?

Cracking is a technique used in oil refineries whereby large and complex hydrocarbon molecules are broken down into smaller and lighter components that are more useful for commercial or consumer use. Cracking is a critical stage in the process of refining crude oil.

What is petroleum cracking explain the need for cracking?

Cracking, in petroleum refining, the process by which heavy hydrocarbon molecules are broken up into lighter molecules by means of heat and usually pressure and sometimes catalysts. Cracking is the most important process for the commercial production of gasoline and diesel fuel.

What is the purpose of cracking hydrocarbons?

Smaller hydrocarbons are more useful as fuels than larger hydrocarbons. Since cracking converts larger hydrocarbons into smaller hydrocarbons, the supply of fuels is improved. This helps to match supply with demand.

What are the 2 types of cracking?

Cracking is primarily of two types – thermal cracking and catalytic cracking. Thermal cracking is further categorised into modern thermal cracking and steam cracking.

What type of reaction is cracking an example of?

thermal decomposition chemical reaction

Which catalyst is used for cracking?


What is the difference between thermal cracking and catalytic cracking?

The main difference between thermal cracking and catalytic cracking is that thermal cracking uses heat energy for the breakdown of compounds whereas catalytic cracking involves a catalyst to obtain products.

Why is broken porcelain used in cracking?

As the porcelain chips are heated the vapour from the paraffin is ‘cracked’, or broken down into smaller hydrocarbons. Cracking them into smaller hydrocarbons makes them easier to use.

How do you prevent suck back in cracking?

To avoid suck-back do not remove the flame from heating the tube while gas is being collected. If suck-back looks as if it is about to occur, lift the whole apparatus by lifting the clamp stand. When a steady stream of gas bubbles is established, collect four tubes full of gas by holding them over the Bunsen valve.

What 2 conditions are necessary for cracking?


  • Thermal cracking uses harsh conditions like high temperature and high pressure.
  • It breaks the alkanes into a high percentage of alkenes and comparatively few alkanes.
  • Thermal cracking is done at about 1,000 degrees Celcius and 70 atm pressure.

What can decane be cracked into?

Cracking decane This can be cracked to form pentane, propene and ethene.

How do you separate the products of cracking?

The reaction products are separated by fractionation. Hydrocracking is also used to crack heavy gas oils (which have over 20 carbon atoms in the hydrocarbon molecule) to shorter chain molecules similar to those in naphtha, which can then be steam cracked to form alkenes.

Why is Aluminium oxide used in cracking?

The larger alkanes are heated to around 650°C and their vapours are passed over a hot catalyst containing aluminium oxide. This causes covalent bonds to break and reform.

Why are long chain alkanes cracked?

This is where cracking comes in. Cracking allows large hydrocarbon molecules to be broken down into smaller, more useful hydrocarbon molecules. Cracking produces a mixture of smaller alkanes and alkenes. This helps to meet the demand for the more useful fractions and to increase profit.

Can alkenes be cracked?

Exam Tip. Remember large alkanes are cracked to produce smaller alkenes. Alkenes are not cracked as they are useful molecules.

What does the catalyst do in cracking?

As the name implies, the catalytic cracking process takes place in the presence of a catalyst. The catalyst promotes breaking of the large molecules in a certain way that maximizes the yield of gasoline. Ideally, all of the “cat-cracked” product would be in the gasoline range, but the technology is not that capable.

Why is catalytic cracking better than thermal cracking?

Catalytic cracking yields a higher quantity of branched-chain, unsaturated, aromatic hydrocarbons as compared to thermal cracking. Catalytic cracking is a better-controlled process than thermal cracking. Petrol obtained by catalytic cracking has lesser sulfur content.

What are the two sections of the fluid catalytic cracking process?

What are the two sections of the fluid catalytic cracking process? Explanation: Reactor is used for cracking process and regenerator for regeneration of catalyst. 5. How is the circulation regulated between the reactor and regenerator in FCC?

What are the products of thermal cracking?

In thermal cracking, high temperatures (typically in the range of 450 °C to 750 °C) and pressures (up to about 70 atmospheres) are used to break the large hydrocarbons into smaller ones. Thermal cracking gives mixtures of products containing high proportions of hydrocarbons with double bonds – alkenes.

Is used as a good catalyst in petroleum cracking?

Hydrocracking catalysts vary widely. The cracking reactions are induced by materials of the silica-alumina type. In units that process residual feedstocks, hydrogenation catalysts such as nickel, tungsten, platinum, or palladium are employed.

Which is the most effective catalyst used in catalytic cracking of petroleum products?

In the fluid catalytic cracking process, the fine, powdery catalyst (typically zeolites, which have an average particle size of ~ 70 μm) takes on the properties of a fluid when it is mixed with the vaporized feed.

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.

What is catalytic cracking of crude oil?

Catalytic cracking is an important process in the oil industry where petroleum vapor passes through a low-density bed of catalyst, which causes the heavier fractions to ‘crack’ producing lighter more valuable products. In the petrochemicals industry they are used for producing polyolefins on a very large scale.

What is required for catalytic cracking?

The catalytic cracking process involves the presence of solid acid catalysts, usually silica-alumina and zeolites. The catalysts promote the formation of carbocations, which undergo processes of rearrangement and scission of C-C bonds.

What does cracking mean in slang?

Crack, or (craic, Irish), Scottish, Northern English and Irish slang for ‘fun’, ‘joke’, ‘gossip’, or ‘mood’.

Why is catalytic cracking important?

Catalytic cracking is now one of the most important processes practiced in petroleum refining as it allows the use of a much larger fraction of crude oil, converting relatively high molecular weight materials into high octane fuels.

What happens in the stabilizer of fixed bed catalytic cracking?

What happens in the stabilizer of fixed-bed catalytic cracking? Explanation: The condensed vapours of the catalytic system are send to the stabilizer, where the dissolved gases are removed and gasoline is recovered. The light gases produced in cracking are no longer allowed to escape into the air.

What is fixed bed catalytic cracking?

Fixed bed cracking In this method, vapors of the heavy oil are heated in the presence of catalyst due to which better yield of petrol is obtained. Heavy oil is vaporized by heating in an electrical heater. Then the vapours are passed over a series of trays containing catalyst.

What are the best anti knocking reagents of petrol?

The typical antiknock agents in use are:

  • Tetraethyllead (still in use as a high octane additive)
  • Alcohol.
  • Methylcyclopentadienyl manganese tricarbonyl (MMT)
  • Ferrocene.
  • Iron pentacarbonyl.
  • Toluene.
  • Isooctane.
  • BTEX – a hydrocarbon mixture of benzene, toluene, xylene and ethyl-benzene, also called gasoline aromatics.