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Catalytic reforming is a chemical process used to convert petroleum refinery naphthas, typically having low octane ratings, into high-octane liquid products called reformates which are components of high-octane gasoline (also known as petrol). An oil refinery is an industrial Process plant where Crude oil is processed and refined into more useful Petroleum products, such as Gasoline Naphtha normally refers to a number of different flammable liquid mixtures of hydrocarbons i The octane rating is a measure of the resistance of Gasoline and other Fuels to Detonation ( Engine knocking) in spark-ignition Basically, the process re-arranges or re-structures the hydrocarbon molecules in the naphtha feedstocks as well as breaking some of the molecules into smaller molecules. In Organic chemistry, a hydrocarbon is an Organic compound consisting entirely of Hydrogen and Carbon. In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by The overall effect is that the product reformate contains hydrocarbons with more complex molecular shapes having higher octane values than the hydrocarbons in the naphtha feedstock. In so doing, the process separates hydrogen atoms from the hydrocarbon molecules and produces very significant amounts of byproduct hydrogen gas for use in a number of the other processes involved in a modern petroleum refinery. Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 History See also Atomic theory, Atomism The concept that matter is composed of discrete units and cannot be divided into arbitrarily tiny Other byproducts are small amounts of methane, ethane, propane and butanes. Methane is a Chemical compound with the molecular formula. It is the simplest Alkane, and the principal component of Natural gas. ETHANE is a mnemonic indicating a protocol used by Emergency services to report situations which they may be faced with especially as it relates to major incidents where Propane is a three- Carbon Alkane, normally a gas but compressible to a liquid that is transportable Butane, also called n -butane, is the unbranched Alkane with four Carbon Atoms CH3CH2CH2CH3

This process is quite different from and not to be confused with the catalytic steam reforming process used industrially to produce various products such as hydrogen, ammonia and methanol from natural gas, naphtha or other petroleum-derived feedstocks. Steam reforming (SR hydrogen reforming or catalytic oxidation, is a method of producing Hydrogen from Hydrocarbons. Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naphtha or wood spirits, is a Chemical compound Nor is this process to be confused with various other catalytic reforming processes that use methanol or biomass-derived feedstocks to produce hydrogen for fuel cells or other uses. Biomass refers to living and recently dead Biological material that can be used as fuel or for industrial production A fuel cell is an electrochemical conversion device It produces electricity from Fuel (on the Anode side and an oxidant (on the

Contents

History

Universal Oil Products (also known as UOP) is a multi-national company developing and delivering technology to the petroleum refining, natural gas processing, petrochemical production and other manufacturing industries. UOP LLC, formerly known as Universal Oil Products, is a multi-national company developing and delivering technology to the Petroleum refining, gas processing An oil refinery is an industrial Process plant where Crude oil is processed and refined into more useful Petroleum products, such as Gasoline Natural gas is a Gaseous Fossil fuel consisting primarily of Methane but including significant quantities of Ethane, Propane, Petrochemicals are chemical products made from raw materials of Petroleum or other Hydrocarbon origin In the 1940s, an eminent research chemist named Vladimir Haensel[1] working for UOP developed a catalytic reforming process using a catalyst containing platinum. Catalysis is the process in which the rate of a Chemical reaction is increased by means of a Chemical substance known as a catalyst Catalysis is the process in which the rate of a Chemical reaction is increased by means of a Chemical substance known as a catalyst Platinum (ˈplætɪnəm is a Chemical element with the Atomic symbol Pt and an Atomic number of 78 Haensel's process was subsequently commercialized by UOP in 1949 for producing a high octane gasoline from low octane naphthas and the UOP process become known as the Platforming process. [2] The first Platforming unit was built in 1949 at the refinery of the Old Dutch Refining Company in Muskegon, Michigan. Muskegon (mus-kēg'n is a city in the US state of Michigan. As of the 2000 census, the city population was 40105 Michigan ( is a Midwestern state of the United States of America.

In the years since then, many other versions of the process have been developed by some of the major oil companies and other organizations. Today, the large majority of gasoline produced worldwide is derived from the catalytic reforming process.

To name a few of the other catalytic reforming versions that were developed, all of which utilized a platinum and/or a rhenium catalyst:

Chemistry

Before describing the reaction chemistry of the catalytic reforming process as used in petroleum refineries, the typical naphthas used as catalytic reforming feedstocks will be discussed.

Typical naphtha feedstocks

A petroleum refinery includes many unit operations and unit processes. In Chemical engineering and related fields a unit operation is a basic step in a Process. Unit processing is the basic processing in Chemical engineering. The first unit operation in a refinery is the continuous distillation of the petroleum crude oil being refined. Continuous distillation, a form of Distillation, is an ongoing separation in which a mixture is continuously (without interruption fed into the process and separated fractions Petroleum ( L petroleum, from Greek πετρέλαιον, lit The overhead liquid distillate is called naphtha and will become a major component of the refinery's gasoline (petrol) product after it is further processed through a catalytic hydrodesulfurizer to remove sulfur-containing hydrocarbons and a catalytic reformer to reform its hydrocarbon molecules into more complex molecules with a higher octane rating value. Hydrodesulfurization (HDS is a Catalytic chemical process widely used to remove Sulfur (S from Natural gas and from refined petroleum products Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16 The naphtha is a mixture of very many different hydrocarbon compounds. It has an initial boiling point of about 35 °C and a final boiling point of about 200 °C, and it contains paraffin, naphthene (cyclic paraffins) and aromatic hydrocarbons ranging from those containing 4 carbon atoms to those containing about 10 or 11 carbon atoms. The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid In chemistry paraffin is the common name for the Alkane Hydrocarbons with the general formula C n H2 n +2 Cycloalkanes (also called naphthenes, especially if from Petroleum sources are types of Alkanes which have one or more rings of Carbon Atoms Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6

The naphtha from the crude oil distillation is often further distilled to produce a "light" naphtha containing most (but not all) of the hydrocarbons with 6 or less carbon atoms and a "heavy" naphtha containing most (but not all) of the hydrocarbons with more than 6 carbon atoms. The heavy naphtha has an initial boiling point of about 140 to 150 °C and a final boiling point of about 190 to 205 °C. The naphthas derived from the distillation of crude oils are referred to as "straight-run" naphthas.

It is the straight-run heavy naphtha that is usually processed in a catalytic reformer because the light naphtha has molecules with 6 or less carbon atoms which, when reformed, tend to crack into butane and lower molecular weight hydrocarbons which are not useful as high-octane gasoline blending components. Also, the molecules with 6 carbon atoms tend to form aromatics which is undesirable because governmental environmental regulations in a number of countries limit the amount of aromatics (most particularly benzene) that gasoline may contain. Benzene, or benzol, is an organic Chemical compound and a known Carcinogen with the molecular formula C 6 H 6 [3][4][5]

It should be noted that there are a great many petroleum crude oil sources worldwide and each crude oil has its own unique composition or "assay". This list of Oil fields includes some of Major oil fields of the past and present A crude oil assay is essentially the chemical evaluation of Crude oil feedstocks by Petroleum testing laboratories Also, not all refineries process the same crude oils and each refinery produces its own straight-run naphthas with their own unique initial and final boiling points. In other words, naphtha is a generic term rather than a specific term.

The table just below lists some fairly typical straight-run heavy naphtha feedstocks, available for catalytic reforming, derived from various crude oils. It can be seen that they differ significantly in their content of paraffins, naphthenes and aromatics:

Typical Heavy Naphtha Feedstocks
Crude oil name \Rightarrow
Location \Rightarrow		 Barrow Island
Australia[6]		 Mutineer-Exeter
Australia[7]		 CPC Blend
Kazakhstan[8]		 Draugen
North Sea[9]
Initial boiling point, °C 149 140 149 150
Final boiling point, °C 204 190 204 180
Paraffins, liquid volume % 46 62 57 38
Naphthenes, liquid volume % 42 32 27 45
Aromatics, liquid volume % 12 6 16 17

Some refinery naphthas include olefinic hydrocarbons, such as naphthas derived from the fluid catalytic cracking and coking processes used in many refineries. In Organic chemistry, an alkene, olefin, or olefine is an unsaturated Chemical compound containing at least one Carbon Fluid catalytic cracking (FCC is the most important conversion process used in petroleum refineries. A delayed coker is a type of coker whose process consists of heating a Residual oil feed to its Thermal cracking temperature in a Furnace with Some refineries may also desulfurize and catalytically reform those naphthas. Hydrodesulfurization (HDS is a Catalytic chemical process widely used to remove Sulfur (S from Natural gas and from refined petroleum products However, for the most part, catalytic reforming is mainly used on the straight-run heavy naphthas, such as those in the above table, derived from the distillation of crude oils.

The reaction chemistry

There are a good many chemical reactions that occur in the catalytic reforming process, all of which occur in the presence of a catalyst and a high partial pressure of hydrogen. In a mixture of Ideal gases each gas has a partial pressure which is the pressure which the gas would have if it alone occupied the volume Depending upon the type or version of catalytic reforming used as well as the desired reaction severity, the reaction conditions range from temperatures of about 495 to 525 °C and from pressures of about 5 to 45 atm. An atmosphere (from Greek ατμός - atmos, " Vapor " + σφαίρα - sphaira, " Sphere " [10]

The commonly used catalytic reforming catalysts contain noble metals such as platinum and/or rhenium, which are very susceptible to poisoning by sulfur and nitrogen compounds. Noble metals are Metals that are resistant to Corrosion or Oxidation, unlike most Base metals They tend to be Precious metals often Catalyst poisoning refers to the effect that a Catalyst can be 'poisoned' if it reacts with another compound that bonds chemically (similar to an inhibitor Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 Therefore, the naphtha feedstock to a catalytic reformer is always pre-processed in a hydrodesulfurization unit which removes both the sulfur and the nitrogen compounds. Hydrodesulfurization (HDS is a Catalytic chemical process widely used to remove Sulfur (S from Natural gas and from refined petroleum products

The four major catalytic reforming reactions are:[11]

1: The dehydrogenation of naphthenes to convert them into aromatics as exemplified in the conversion methylcyclohexane (a naphthene) to toluene (an aromatic), as shown below:


2: The isomerization of normal paraffins to isoparaffins as exemplified in the conversion of normal octane to 2,5-Dimethylhexane (an isoparaffin), as shown below:


3: The dehydrogenation and aromatization of paraffins to aromatics (commonly called dehydrocyclization) as exemplified in the conversion of normal heptane to toluene, as shown below:


4: The hydrocracking of paraffins into smaller molecules as exemplified by the cracking of normal heptane into isopentane and ethane, as shown below:


The hydrocracking of paraffins is the only one of the above four major reforming reactions that consumes hydrogen. Dehydrogenation is a chemical reaction that involves the elimination of Hydrogen (H2 Toluene, also known as methylbenzene or phenylmethane, is a clear water -insoluble liquid with the typical smell of Paint thinners redolent of In Chemistry isomerisation is the process by which one Molecule is transformed into another molecule which has exactly the same atoms but the atoms are rearranged Alkanes, also known as Paraffins are Chemical compounds that consist only of the elements Carbon (C and Hydrogen (H (i Octane is a straight-chain Alkane with the Chemical formula CH3(CH26CH3 n -Heptane is the straight-chain Alkane with the Chemical formula H3C(CH25CH3 or C7H16 In Petroleum geology and Chemistry, cracking is the process whereby complex organic Molecules such as Kerogens or heavy Hydrocarbons Isopentane, C5[[hydrogen H12]] also called methylbutane or 2-methylbutane, is a branched-chain Alkane with five The isomerization of normal paraffins does not consume or produce hydrogen. However, both the dehydrogenation of naphthenes and the dehydrocyclization of paraffins produce hydrogen. The overall net production of hydrogen in the catalytic reforming of petroleum naphthas ranges from about 50 to 200 cubic meters of hydrogen gas (at 0 °C and 1 atm) per cubic meter of liquid naphtha feedstock. CM3 redirects here If you were looking for the 3rd game in the Cooking Mama series abbreviated as CM3 see here. In the United States customary units, that is equivalent to 300 to 1200 cubic feet of hydrogen gas (at 60 °F and 1 atm) per barrel of liquid naphtha feedstock. US customary units, also known in the United States as English units or Imperial units (in reference to the British Empire) (but see English The cubic foot is an imperial and US customary (non- metric) unit of Volume, used in the United States Canada and the United Kingdom [12] In many petroleum refineries, the net hydrogen produced in catalytic reforming supplies a significant part of the hydrogen used elsewhere in the refinery (for example, in hydrodesulfurization processes).

Process description

The most commonly used type of catalytic reforming unit has three reactors, each with a fixed bed of catalyst, and all of the catalyst is regenerated in situ during routine catalyst regeneration shutdowns which occur approximately once each 6 to 24 months. In Chemical engineering, chemical reactors are vessels designed to contain Chemical reactions The design of a chemical reactor deals with multiple aspects of In situ (ɪn siːˈtuː is a Latin phrase meaning in the place. Such a unit is referred to as a semi-regenerative catalytic reformer (SRR).

Some catalytic reforming units have an extra spare or swing reactor and each reactor can be individually isolated so that any one reactor can be undergoing in situ regeneration while the other reactors are in operation. When that reactor is regenerated, it replaces another reactor which, in turn, is isolated so that it can then be regenerated. Such units, referred to as cyclic catalytic reformers, are not very common. Cyclic catalytic reformers serve to extend the period between required shutdowns.

The latest and most modern type of catalytic reformers are called continuous catalyst regeneration reformers (CCR). Such units are characterized by continuous in-situ regeneration of part of the catalyst in a special regenerator, and by continuous addition of the regenerated catalyst to the operating reactors. As of 2006, two CCR versions available: UOP's CCR Platformer process[13] and Axen's Octanizing process. [14] The installation and use of CCR units is rapidly increasing.

Many of the earliest catalytic reforming units (in the 1950's and 1960's) were non-regenerative in that they did not perform in situ catalyst regeneration. Instead, when needed, the aged catalyst was replaced by fresh catalyst and the aged catalyst was shipped to catalyst manufacturer's to be either regenerated or to recover the platinum content of the aged catalyst. Very few, if any, catalytic reformers currently in operation are non-regenerative.

The process flow diagram below depicts a typical semi-regenerative catalytic reforming unit. A process flow diagram (PFD is a diagram commonly used in chemical and Process engineering to indicate the general flow of plant processes and equipment

Schematic diagram of a typical semi-regenerative catalytic reformer unit in a petroleum refinery
Schematic diagram of a typical semi-regenerative catalytic reformer unit in a petroleum refinery

The liquid feed (at the bottom left in the diagram) is pumped up to the reaction pressure (5 to 45 atm) and is joined by a stream of hydrogen-rich recycle gas. For information on Wikipedia project-related discussions see WikipediaVillage pump. The resulting liquid-gas mixture is preheated by flowing through a heat exchanger. A heat exchanger is a device built for efficient Heat transfer from one medium to another whether the media are separated by a solid wall so that they never mix or the media The preheated feed mixture is then totally vaporized and heated to the reaction temperature (495 to 520 °C) before the vaporized reactants enter the first reactor. Evaporation is the process by which Molecules in a Liquid state (e As the vaporized reactants flow through the fixed bed of catalyst in the reactor, the major reaction is the dehydrogenation of naphthenes to aromatics (as described earlier herein) which is highly endothermic and results in a large temperature decrease between the inlet and outlet of the reactor. In Thermodynamics, the word endothermic "within-heating" describes a process or reaction that absorbs Energy in the form of Heat. To maintain the required reaction temperature and the rate of reaction, the vaporized stream is reheated in the second fired heater before it flows through the second reactor. The temperature again decreases across the second reactor and the vaporized stream must again be reheated in the third fired heater before it flows through the third reactor. As the vaporized stream proceeds through the three reactors, the reaction rates decrease and the reactors therefore become larger. At the same time, the amount of reheat required between the reactors becomes smaller. Usually, three reactors are all that is required to provide the desired performance of the catalytic reforming unit.

Some installations use three separate fired heaters as shown in the schematic diagram and some installations use a single fired heater with three separate heating coils.

The hot reaction products from the third reactor are partially cooled by flowing through the heat exchanger where the feed to the first reactor is preheated and then flow through a water-cooled heat exchanger before flowing through the pressure controller (PC) into the gas separator.

Most of the hydrogen-rich gas from the gas separator vessel returns to the suction of the recycle hydrogen gas compressor and the net production of hydrogen-rich gas from the reforming reactions is exported for use in other the other refinery processes that consume hydrogen (such as hydrodesulfurization units and/or a hydrocracker unit). A gas compressor is a mechanical device that increases the Pressure of a Gas by reducing its Volume. In Petroleum geology and Chemistry, cracking is the process whereby complex organic Molecules such as Kerogens or heavy Hydrocarbons

The liquid from the gas separator vessel is routed into a fractionating column commonly called a stabilizer. A fractionating column or fractionation column is an essential item used in the Distillation of liquid mixtures so as to separate the mixture into its component parts The overhead offgas product from the stabilizer contains the byproduct methane, ethane, propane and butane gases produced by the hydrocracking reactions as explained in the above discussion of the reaction chemistry of a catalytic reformer, and it may also contain some small amount of hydrogen. That offgas is routed to the refinery's central gas processing plant for removal and recovery of propane and butane. The residual gas after such processing becomes part of the refinery's fuel gas system.

The bottoms product from the stabilizer is the high-octane liquid reformate that will become a component of the refinery's product gasoline.

Catalysts and mechanisms

Most catalytic reforming catalysts contain platinum or rhenium on a silica or silica-alumina support base, and some contain both platinum and rhenium. The Chemical compound silicon dioxide, also known as silica or silox (from the Latin " Silex " is an Oxide Fresh catalyst is chlorided (chlorinated) prior to use. The chloride Ion is formed when the element Chlorine picks up one Electron to form an Anion (negatively-charged ion Cl&minus

The noble metals (platinum and rhenium) are considered to be catalytic sites for the dehydrogenation reactions and the chlorinated alumina provides the acid sites needed for isomerization, cyclization and hydrocracking reactions. In Computer science, ACID ( Atomicity Consistency Isolation Durability) is a set of properties that guarantee that Database transactions are [11]

The activity (i. e. , effectiveness) of the catalyst in a semi-regenerative catalytic reformer is reduced over time during operation by carbonaceous coke deposition and chloride loss. Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 The activity of the catalyst can be periodically regenerated or restored by in situ high temperature oxidation of the coke followed by chlorination. As stated earlier herein, semi-regenerative catalytic reformers are regenerated about once per 6 to 24 months.

Normally, the catalyst can be regenerated perhaps 3 or 4 times before it must be returned to the manufacturer for reclamation of the valuable platinum and/or rhenium content. [11]

References

  1. ^ A Biographical Memoir of Vladimir Haensel written by Stanley Gembiki, published by the National Academy of Sciences in 2006.
  2. ^ Platforming described on UOP's website
  3. ^ Canadian regulations on benzene in gasoline
  4. ^ United Kingdom regulations on benzene in gasoline
  5. ^ USA regulations on benzene in gasoline
  6. ^ Barrow Island crude oil assay
  7. ^ Mutineer-Exeter crude oil assay
  8. ^ CPC Blend crude oil assay
  9. ^ Draugen crude oil assay
  10. ^ OSHA Technical Manual, Section IV, Chapter 2, Petroleum refining Processes (A publication of the Occupational Safety and Health Administration)
  11. ^ a b c Gary, J. The United States Occupational Safety and Health Administration (OSHA is an agency of the United States Department of Labor. H. and Handwerk, G. E. (1984). Petroleum Refining Technology and Economics, 2nd Edition, Marcel Dekker, Inc. ISBN 0-8247-7150-8.  
  12. ^ US Patent 5011805, Dehydrogenation, dehydrocyclization and reforming catalyst (Inventor: Ralph Dessau, Assignee: Mobil Oil Corporation)
  13. ^ CCR Platforming (UOP website)
  14. ^ Octanizing Options (Axens website)

External links

The Delft University of Technology ( Technische Universiteit Delft in Dutch) in Delft, the Netherlands, is the nation's largest technical The Netherlands ( Dutch:, ˈnedərlɑnt is the European part of the Kingdom of the Netherlands, which consists of the Netherlands the Netherlands
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