Why is catalytic cracking done

This vessel collects catalyst fines that have been suspended in slurry oil from the process. The separated slurry oil is decanted from the top of the vessel for re-use while the catalyst fines precipitate inside of the slurry tank forming a hard, concrete-like solid. The catalyst solids are impregnated with hydrocarbons that make the catalyst fines a hazardous waste that carries an EPE K hazardous waste code. This material is expensive to dispose.

Recent develops in extraction chemistry have resulted in a process and chemical products that are effective in removing low PPM-levels of the numerous constituents that comprise the K-code and allow for a non-hazardous disposal of the spent catalyst fines through conventional non-hazardous waste disposal facilities.

Imagine the savings to be gained in non-hazardous disposal. Through these conversations about refinery operations, we have tried to remove the sales pitch component, even though this is not completely possible. Our goal is to bring to your attention to new developments in the industry and the field of chemistry that will prove beneficial in your operations. Chemistry is dynamic and ever learning new ways to address concerns that you encounter every day.

The year is coming to an end. We wish the very best for the new year to all of our friends in the oil and gas and petroleum refining business and a very Merry Christmas to all. Generic filters Hidden label. Hidden label. Part 13 Catalytic Cracking. Reading Time: 8 minutes. It quickly became apparent that meeting the market demands for straight-run gasoline would result in a glut in the marketplace of the heavier fuel oil crude fractions.

In order to increase gasoline products catalytic cracking is used. Catalytic cracking consists of three major processes:. Reaction Regeneration Fractionation. There are three basic types of catalytic crackers:. Fluid bed Moving bed Fixed bed. The reaction chamber in which the hot feed is mixed with the catalyst and the cracking reactions take place The regenerator in which the catalyst is regenerated by burning the coke produced in the reactor from its surface The fractionator where the cracked hydrocarbons are separated into useful products.

Types of Fouling Operational deposits on the hydrocarbon side of a cracking unit will typically be a mixture of organic and inorganic materials consisting of iron, sulfates and sulfides. For example, hexane can be cracked to form butane and ethene:.

The first product will also follow this rule. The second product will contain all the other C and H atoms. The second product is an alkene, so it will follow the rule C n H 2n. C 16 H 34 is an alkane which can be used as the starting chemical in cracking. One of the products of cracking this compound is an alkane which has 10 carbon atoms in it. If you need to know about thermal cracking in detail, a Google search on thermal cracking will throw up lots of useful leads.

Be careful to go to industry or similarly reliable sources. Thermal cracking doesn't go via ionic intermediates like catalytic cracking. Instead, carbon-carbon bonds are broken so that each carbon atom ends up with a single electron. In other words, free radicals are formed. Steam cracking is useful because it produces a high proportion of alkenes in the cracked mixture.

It uses the naphtha or sometimes gas oil fraction as the feedstock as well as more simple hydrocarbons like ethane, propane or butane. The pressure of the mixture is around 1 atmosphere.

The gas flow is very, very fast so that the mixture only remains in the reactor for less than a second. This is to prevent the hydrocarbons cracking to produce carbon.

The steam plays no chemical part in the process, serving mainly to dilute the organic feedstock. This helps to prevent the formation of carbon.

Note: If you are interested, there is a lot of really useful information on cracking on this page from the Essential Chemical Industry. Today in Energy. December 11, Fluid catalytic cracking is an important step in producing gasoline Source: Reproduced with permission from Valero Energy Corporation. Source: U. Email Share Print. Send your feedback to todayinenergy eia.