14/15 Fall semester

Petroleum and Gas Processing(TKK-2136)

Instructor: Rama Oktavian Email: [email protected]

Office Hr.: M.13-15, Tu. 13-15, W. 13-15, Th. 13-15, F. 09-11

1. Fluidized Catalytic cracking 2. FCC configuration 3. FCC material balance

Outlines

Fluidized catalytic cracking

Fluidized catalytic cracking

FCC process

The fluidised catalytic cracking (FCC) unit is the heart of the refinery and is where

stream heavy low-value petroleum

such as vacuum gas oil (VGO) is upgraded into higher value products,

mainly gasoline and C3/C4 olefins

, which can be used in the alkylation unit for production of gasoline (C7 –C8 alkylates).

Major developments have occurred in two areas: new catalysts and new reactor and regenerator designs.

Role of FCC process

Fluidized catalytic cracking   The role of the FCC is to take heavy desulphurised feedstock and crack it into lighter, mainly high octane gasoline.

The FCC also produces olefins (C5+ and C4+) and LPG.

Fluidized catalytic cracking

FCC feedstock

 The main feedstock used in a FCC unit is paraffinic molecules. the gas oil , which can be considered mixtures of aromatic, naphthanic and  There are also varying amounts of contaminants such as sulphur, nitrogen and metals. To protect the catalyst, feed pre-treatment by hydrotreating is required in order to remove contaminants and improve cracking characteristics and yields .

FCC feedstock

Fluidized catalytic cracking

FCC products

Fluidized catalytic cracking

Fluidized catalytic cracking The main reaction in the FCC is the catalytic cracking of paraffin, olefins, naphthenes and side chains in aromatics.    The VGO undergoes the desired ‘primary cracking’ into gasoline and LCO. A secondary reaction also occurs, which must be limited, such as a hydrogen transfer reaction which lowers the gasoline yield and causes the cycloaddition reaction. The latter could lead to coke formation (needed to provide heat for catalyst regeneration).

Fluidized catalytic cracking

Primary reaction

a. Olefins – smaller olefins b. Alkylaromatics – Dealkylation c. Alkylaromatics – Side chain cracking

Secondary reaction

a. Isomerisation Fluidized catalytic cracking The final product is the transformation of paraffins and olefins to isoparaffins.

b. Cyclisation The final result would be the cyclisation of olefins to naphthenes and possibly further cyclisation to coke.

FCC reaction summary

Fluidized catalytic cracking

Fluidized catalytic cracking

FCC configuration

 The basic configuration of the FCC unit is a reactor (riser) and a regenerator.

Fluidized catalytic cracking

FCC configuration

 The basic configuration of the FCC unit is a reactor (riser) and a regenerator.

Process description

Fluidized catalytic cracking -endothermic reactions - residence time =2–10 s 649–760 ˚C 316–427 ˚C riser Steam and VGO heated are fed to the bottom of the riser.

The regenerated hot catalyst at is also fed to the bottom of the riser.

Fluidized catalytic cracking CO, CO 2 , H 2 O, Air 482 –538 ˚C -Steam is injected into the stripper section, and the oil is removed from the catalyst with the help of some baffles installed in the stripper. -The oil is stripped in this way from the catalyst and the spent catalyst is sent to the regenerator. -The coke in the spent catalyst is burned off in the regenerator by introducing excess air

-Hydrocyclones are installed to catch any solid particles carried out in the overheated stream. -The product gases from the reactor are sent to the fractionator .

-The light gases are sent to the riser with the HCO.

gas concentration unit . -The filtered decant can be used as an aromatic solvent or recycled back to the

Process condition

Fluidized catalytic cracking

FCC Yield correlation

Fluidized catalytic cracking

Fluidized catalytic cracking

FCC Yield correlation example

Solution

Fluidized catalytic cracking

Solution

Fluidized catalytic cracking

Fluidized catalytic cracking

Material and energy balance in FCC

Fluidized catalytic cracking

Material and energy balance in FCC