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Petroleum and Gas Processing(TKK-2136)

14/15 Fall semester

Instructor: Rama OktavianEmail: rama.oktavian86@gmail.comOffice Hr.: M.13-15, Tu. 13-15, W. 13-15, Th. 13-15, F. 09-11

Outlines

1. Catalytic reforming

2. Reformer configuration

3. Reformer material balance

4. Isomerization

Catalytic reforming

Catalytic reformingCatalytic reforming process

a catalytic process which converts low octane naphthenic into higher octane reformate products. It is a highly endothermic process requiring large amounts of energy. the process of transforming C7–C10 hydrocarbons with low octane numbers to aromatics and iso-paraffins which have high octane numbers

gasoline blending and aromatic rich reformate for aromatic production

Catalytic reformingReformer feed characterization

Catalytic reformingReformer feed and product characterization

FEED PRODUCT

Paraffins 30-70 30-50

Olefins 0-2 0-2

Naphthenes 20-60 0-3

Aromatics 7-20 45-60

Catalytic reformingResearch Octane Number (RON)

the percentage by volume of iso-octane in a mixture of iso-octane and n-heptane

Catalytic reformingRole of reformer

Catalytic reformingRole of reformer

The catalytic reformer is one of the major units for gasoline production in refineries.

It can produce 37 wt% of the total gasoline pool. Other units

- fluid catalytic cracker (FCC) - alkylation unit - isomerization unit

Catalytic reformingReforming reaction

1. Naphthene Dehydrogenation of Cyclohexanes2. Paraffin Dehydrogenation3. Dehydrocyclization4. Isomerization5. Hydrocracking Reactions6. Coke Deposition

Reforming reaction network

Catalytic reformingCalculating dehydrogenation reaction

Catalytic reformingReforming reaction

1. Naphthene Dehydrogenation of Cyclohexanes2. Paraffin Dehydrogenation3. Dehydrocyclization4. Isomerization5. Hydrocracking Reactions6. Coke Deposition

Catalytic reformingProcess step in catalytic reforming

1. Feed preparation: Naphtha Hydrotreatment removal of the various catalyst poisons - sulfur, nitrogen, halogens, oxygen, water, olefins, di olefins, arsenic and other metals

Catalytic reformingProcess step in catalytic reforming

2. Preheating: Temperature Control

3. Catalytic Reforming and Catalyst Circulation and Regeneration incase of continuous reforming process

4. Product separation: Removal of gases and Reformate by fractional Distillation

5. Separation of aromatics in case of Aromatic production

Catalytic reformingClassification of process

1. Semi-Regenerative Fixed Bed reactors

2. Cyclic Fixed Bed Reformers - Adding an extra-reactor to avoid shutting down the whole unit during regeneration. Three reactors can be running while the forth is being regenerated

3. Continuous Reformers

Catalytic reformingClassification of process

1. Semi-Regenerative Fixed Bed reactors

Catalytic reformingSemi-Regenerative Fixed Bed reactors

first reactor Reactions such as dehydrogenation of paraffins and naphthenes which are very rapid and highly endothermic

Catalytic reformingSemi-Regenerative Fixed Bed reactors

second reactor Reactions that are considered rapid, such as paraffin isomerization and naphthens dehydroisomerization, give moderate temperature decline

Catalytic reformingSemi-Regenerative Fixed Bed reactors

Third reactor slow reactions such as dehydrocyclization and hydrocracking give low temperature decline.

Catalytic reformingClassification of process

1. Semi-Regenerative Fixed Bed reactors

Catalytic reformingClassification of process

3. Continuous Reformers

Licensed by CCR Platforming UOP Process

Process description- The catalyst moves downwards by gravity from the first reactor (R1) to the

forth reactor (R4)

- The catalyst is sent to the regenerator to burn off the coke and then sent back to the first reactor R1

- The final product from R4 is sent to the stabilizer and gas recovery section

Process variable- operated at lower hydrogen partial pressure (PH2 = 3 bar)- reformate yield gain of nearly 10 vol%

Catalytic reformingClassification of process

3. Continuous Reformers

Catalytic reformingVariable process

1. Catalyst type – affect basic catalyst formulation (metal-acid loading), chloride level, platinum level, and activator level - The catalyst used for reforming is a bifunctional catalyst composed of platinum metal on chlorinated alumina

2. Reaction temperature – control the reaction rate and product, usually operates at 560 C, above that temperature will form petroleum coke

3. Space velocity – higher space velocity will decrease residence time and lower Octane number of product

4. Reactor pressure – will affect to yield of product or hydrogen formation

5. Hydrogen/Hydrocarbon ratio

Catalytic reformingCatalyst type

The catalyst used for reforming is a bifunctional catalyst composed of platinum metal on chlorinated alumina.

Platinum the centre for the dehydrogenation reaction

an acidic site to promote structure changes - cyclization of paraffins - isomerization of the naphthenes.

chlorinated alumina

Catalytic reformingCatalyst type

Impurities that might cause deactivation or poisoning of the catalyst include: coke, sulphur, nitrogen, metals and water.

The reformer should be operated at high temperature and low pressure to minimize coke deposition.

Catalytic reformingProcess comparison

Catalytic reformingCalculating material balance in catalytic reformer

Yield correlations for the reformer were developed as given

Catalytic reformingCalculating material balance in catalytic reformer

Example

Solution

Catalytic reformingCalculating material balance in catalytic reformer

Solution

IsomerizationIsomerization of Light Naphtha

Isomerization is the process in which light straight chain paraffins of low RON (C6, C5 and C4) are transformed with proper catalyst into branched chains with the same carbon number and high octane numbers.

Light naphtha from the hydrotreated naphtha (HTN) C5=80 ˚C is used as a feed to the isomerization unit.

IsomerizationIsomerization reaction

Isomerization is a reversible and slightly exothermic reaction:

The conversion to iso-paraffin is not complete since the reaction is equilibrium conversion limited. It does not depend on pressure, but it can be increased by lowering the temperature.

However operating at low temperatures will decrease the reaction rate. For this reason a very active catalyst must be used.

IsomerizationIsomerization catalysts

Two types of isomerization catalysts

The standard Pt/chlorinated alumina with high chlorine content

The Pt/zeolite catalyst

IsomerizationStandard isomerization catalysts

This bi-functional nature catalyst consists of highly chlorinated alumina responsible for the acidic function of the catalyst.

Platinum is deposited (0.3–0.5 wt%) on the alumina matrix.

Platinum in the presence of hydrogen will prevent coke deposition, thus ensuring high catalyst activity.

The reaction is performed at low temperature at about 130 ˚C to improve the equilibrium yield.

IsomerizationZeolite catalyst

Zeolites are used to give an acidic function to the catalyst.

Metallic particles of platinum are impregnated on the surface of zeolites and act as hydrogen transfer centres.

The zeolite catalyst can resist impurities and does not require feed pretreatment, but it does have lower activity and thus the reaction must be performed at a higher temperature of 250 ˚C (482 F).

IsomerizationIsomerization catalyst comparison

IsomerizationIsomerization yield

The reformate yield from light naphtha isomerization is usually very high (>97 wt%).

Typical yields are given in Table

IsomerizationIsomerization yield balance

IsomerizationSolution

Isomerization yields