4 Catalytic reforming Catalytic 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 numbersgasoline blending and aromatic rich reformate for aromatic production
9 Catalytic reformingRole of reformerThe 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
13 Catalytic reforming Process step in catalytic reforming Feed preparation: Naphtha Hydrotreatmentremoval of the various catalyst poisons - sulfur, nitrogen, halogens, oxygen,water, olefins, di olefins, arsenic and other metals
14 Catalytic reforming Process step in catalytic reforming 2. Preheating: Temperature Control3. Catalytic Reforming and Catalyst Circulation and Regeneration incase of continuous reforming process4. Product separation: Removal of gases and Reformate by fractional Distillation5. Separation of aromatics in case of Aromatic production
15 Catalytic reforming Classification of process Semi-Regenerative Fixed Bed reactorsCyclic 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 regeneratedContinuous Reformers
16 Catalytic reforming Classification of process Semi-Regenerative Fixed Bed reactors
17 Catalytic reforming Semi-Regenerative Fixed Bed reactors Reactions such as dehydrogenation of paraffins and naphthenes which are very rapid and highly endothermicfirst reactor
18 Catalytic reformingSemi-Regenerative Fixed Bed reactorsReactions that are considered rapid, such as paraffin isomerization and naphthens dehydroisomerization, give moderate temperature declinesecond reactor
19 Catalytic reformingSemi-Regenerative Fixed Bed reactorsslow reactions such as dehydrocyclization and hydrocracking give low temperature decline.Third reactor
20 Catalytic reforming Classification of process Semi-Regenerative Fixed Bed reactors
21 Catalytic reforming Classification of process 3. Continuous Reformers Licensed by CCR Platforming UOP ProcessProcess descriptionThe 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 R1The final product from R4 is sent to the stabilizer and gas recovery sectionProcess variableoperated at lower hydrogen partial pressure (PH2 = 3 bar)reformate yield gain of nearly 10 vol%
22 Catalytic reformingClassification of process3. Continuous Reformers
23 Catalytic reforming Variable process 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 aluminaReaction temperature – control the reaction rate and product, usually operates at 560 C, above that temperature will form petroleum cokeSpace velocity – higher space velocity will decrease residence time and lower Octane number of productReactor pressure – will affect to yield of product or hydrogen formationHydrogen/Hydrocarbon ratio
24 Catalytic reformingCatalyst typeThe catalyst used for reforming is a bifunctional catalyst composed of platinum metal on chlorinated alumina.the centre for the dehydrogenation reactionPlatinuman acidic site to promote structure changes- cyclization of paraffins- isomerization of the naphthenes.chlorinated alumina
25 Catalytic reformingCatalyst typeImpurities 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.
27 Catalytic reforming Calculating material balance in catalytic reformer Yield correlations for the reformer were developed as given
28 Catalytic reforming Calculating material balance in catalytic reformer ExampleSolution
29 Catalytic reforming Calculating material balance in catalytic reformer Solution
30 IsomerizationIsomerization of Light NaphthaIsomerization 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.
31 IsomerizationIsomerization reactionIsomerization 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.
32 Isomerization Two types of isomerization catalysts The standard Pt/chlorinated alumina with high chlorine contentThe Pt/zeolite catalyst
33 IsomerizationStandard isomerization catalystsThis 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.
34 IsomerizationZeolite catalystZeolites 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).