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77-472: [REDACTED] Look up platforming in Wiktionary, the free dictionary. Platforming may refer to: A catalytic reforming process The mechanics of a platform game See also [ edit ] Deplatforming , an administrative or political action to deny access to a platform to express opinions Platform (disambiguation) Topics referred to by

154-433: A catalytic reformer to reform its hydrocarbon molecules into more complex molecules with a higher octane rating value. The naphtha cut, as that fraction is called, contains many different hydrocarbon compounds. Therefore, it has an initial boiling point of about 35 °C and a final boiling point of about 200 °C. Each cut produced in the fractionating columns has a different boiling range. At some distance below

231-551: A silica or silica-alumina support base . Fresh catalyst is chlorided (chlorinated) prior to use. The noble metals (platinum and rhenium) are catalytic sites for the dehydrogenation reactions and the chlorinated alumina provides the acid sites needed for isomerization, cyclization and hydrocracking reactions. Chlorination requires finesse, lest it affect the Pt or Re component. The platinum and/or rhenium are very susceptible to poisoning by sulfur and nitrogen compounds. Therefore,

308-494: A catalytic reformer to reform its hydrocarbon molecules into more complex molecules with a higher octane rating value. 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 6 carbon atoms to those containing about 10 or 11 carbon atoms. The naphtha from

385-420: A continuous distillation column is in operation, it has to be closely monitored for changes in feed composition, operating temperature and product composition. Many of these tasks are performed using advanced computer control equipment. The column can be fed in different ways. If the feed is from a source at a pressure higher than the distillation column pressure, it is simply piped into the column. Otherwise,

462-401: A continuous distillation, each of the fraction streams is taken simultaneously throughout operation; therefore, a separate exit point is needed for each fraction. In practice when there are multiple distillate fractions, the distillate exit points are located at different heights on a fractionating column . The bottoms fraction can be taken from the bottom of the distillation column or unit, but

539-410: A continuous distillation, the system is kept in a steady state or approximate steady state. Steady state means that quantities related to the process do not change as time passes during operation. Such constant quantities include feed input rate, output stream rates, heating and cooling rates, reflux ratio, and temperatures , pressures, and compositions at every point (location). Unless the process

616-563: A distillation tower uses packing instead of trays, the number of necessary theoretical equilibrium stages is first determined and then the packing height equivalent to a theoretical equilibrium stage , known as the height equivalent to a theoretical plate (HETP), is also determined. The total packing height required is the number of theoretical stages multiplied by the HETP. This packing material can either be random dumped packing such as Raschig rings or structured sheet metal . Liquids tend to wet

693-542: A form of distillation , is an ongoing separation in which a mixture is continuously (without interruption) fed into the process and separated fractions are removed continuously as output streams. Distillation is the separation or partial separation of a liquid feed mixture into components or fractions by selective boiling (or evaporation ) and condensation . The process produces at least two output fractions. These fractions include at least one volatile distillate fraction, which has boiled and been separately captured as

770-449: A given separation is calculated using a specific vapor to liquid ratio. If the liquid and vapor are not evenly distributed across the superficial tower area as it enters the packed bed, the liquid to vapor ratio will not be correct in the packed bed and the required separation will not be achieved. The packing will appear to not be working properly. The height equivalent to a theoretical plate (HETP) will be greater than expected. The problem

847-430: A minimum, require quite significant downtime). Distillation towers (such as in images 3 and 4) use various vapor and liquid contacting methods to provide the required number of equilibrium stages . Such devices are commonly known as "plates" or "trays". Each of these plates or trays is at a different temperature and pressure. The stage at the tower bottom has the highest pressure and temperature. Progressing upwards in

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924-441: A partial flash vaporization resulting in a liquid-vapor mixture as it enters the distillation column. Although small size units, mostly made of glass, can be used in laboratories, industrial units are large, vertical, steel vessels (see images 1 and 2) known as "distillation towers" or "distillation columns". To improve the separation, the tower is normally provided inside with horizontal plates or trays as shown in image 5, or

1001-476: A platinum and/or a rhenium catalyst: A petroleum refinery includes many unit operations and unit processes . The first unit operation in a refinery is the continuous distillation of the petroleum crude oil being refined. 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

1078-861: A series of distillation columns, i.e. the distillation train. A distillation train is defined by a sequence of distillation columns arranged in series or in parallel whose aim is the multicomponent mixtures purification. The Dividing Wall Column unit is most common process-intensifying unit related to distillation. In particular, it is the arrangement in a single column shell of the Petlyuk configuration that has been proved to be thermodynamically equivalent. Petroleum crude oils contain hundreds of different hydrocarbon compounds: paraffins , naphthenes and aromatics as well as organic sulfur compounds , organic nitrogen compounds and some oxygen -containing hydrocarbons such as phenols . Although crude oils generally do not contain olefins , they are formed in many of

1155-405: A significant part of the hydrogen used elsewhere in the refinery (for example, in hydrodesulfurization processes). The hydrogen is also necessary in order to hydrogenolyze any polymers that form on the catalyst. In practice, the higher the content of naphthenes in the naphtha feedstock, the better will be the quality of the reformate and the higher the production of hydrogen. Crude oils containing

1232-416: A typical semi-regenerative catalytic reforming unit. The liquid feed (at the bottom left in the diagram) is pumped up to the reaction pressure (5–45 atm) and is joined by a stream of hydrogen-rich recycle gas. The resulting liquid–gas mixture is preheated by flowing through a heat exchanger . The preheated feed mixture is then totally vaporized and heated to the reaction temperature (495–520 °C) before

1309-548: 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

1386-412: A vapor condensed to a liquid, and practically always a bottoms (or residuum ) fraction, which is the least volatile residue that has not been separately captured as a condensed vapor. An alternative to continuous distillation is batch distillation , where the mixture is added to the unit at the start of the distillation, distillate fractions are taken out sequentially in time (one after another) during

1463-565: 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: Some refinery naphthas include olefinic hydrocarbons , such as naphthas derived from the fluid catalytic cracking and coking processes used in many refineries. Some refineries may also desulfurize and catalytically reform those naphthas. However, for

1540-473: Is also dependent on the feedstock. However, independently of the crude oil used in the refinery, all catalysts require a maximum final boiling point of the naphtha feedstock of 180 °C. 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. The sensitivity of catalytic reforming to contamination by sulfur and nitrogen requires hydrotreating

1617-550: Is available. The heavy reformate is high in octane and low in benzene, hence it is an excellent blending component for the gasoline pool. Benzene is often removed with a specific operation to reduce the content of benzene in the reformate as the finished gasoline has often an upper limit of benzene content (in the UE this is 1% volume). The benzene extracted can be marketed as feedstock for the chemical industry. Most catalytic reforming catalysts contain platinum with or without some rhenium on

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1694-579: Is different from Wikidata All article disambiguation pages All disambiguation pages Catalytic reforming In addition to a gasoline blending stock, reformate is the main source of aromatic bulk chemicals such as benzene , toluene , xylene and ethylbenzene , which have diverse uses, most importantly as raw materials for conversion into plastics. However, the benzene content of reformate makes it carcinogenic , which has led to governmental regulations effectively requiring further processing to reduce its benzene content. Catalytic reforming

1771-470: Is disturbed due to changes in feed, heating, ambient temperature, or condensing, steady state is normally maintained. This is also the main attraction of continuous distillation, apart from the minimum amount of (easily instrumentable) surveillance; if the feed rate and feed composition are kept constant, product rate and quality are also constant. Even when a variation in conditions occurs, modern process control methods are commonly able to gradually return

1848-455: Is not the packing itself but the mal-distribution of the fluids entering the packed bed. Liquid mal-distribution is more frequently the problem than vapor. The design of the liquid distributors used to introduce the feed and reflux to a packed bed is critical to making the packing perform at maximum efficiency. Methods of evaluating the effectiveness of a liquid distributor can be found in references. Images 4 and 5 assume an overhead stream that

1925-411: Is often taken from a reboiler connected to the bottom of the column. Each fraction may contain one or more components (types of chemical compounds ). When distilling crude oil or a similar feedstock, each fraction contains many components of similar volatility and other properties. Although it is possible to run a small-scale or laboratory continuous distillation, most often continuous distillation

2002-433: Is quite different from and not to be confused with the catalytic steam reforming process used industrially to produce products such as hydrogen , ammonia , and methanol from natural gas , naphtha or other petroleum-derived feedstocks. 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. In

2079-518: Is rapidly increasing. Many of the earliest catalytic reforming units (in the 1950s and 1960s) 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 manufacturers 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

2156-404: Is totally condensed into a liquid product using water or air-cooling. However, in many cases, the tower overhead is not easily condensed totally and the reflux drum must include a vent gas outlet stream. In yet other cases, the overhead stream may also contain water vapor because either the feed stream contains some water or some steam is injected into the distillation tower (which is the case in

2233-407: Is typically performed in large, vertical cylindrical columns (as shown in images 1 and 2) known as "distillation towers" or "distillation columns" with diameters ranging from about 65 centimeters to 11 meters and heights ranging from about 6 meters to 60 meters or more. The principle for continuous distillation is the same as for normal distillation: when a liquid mixture is heated so that it boils,

2310-495: Is undesirable because governmental environmental regulations in a number of countries limit the amount of aromatics (most particularly benzene ) that gasoline may contain. There are a great many petroleum crude oil sources worldwide and each crude oil has its own unique composition or "assay" . 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

2387-593: Is used in a large-scale industrial process. Distillation is one of the unit operations of chemical engineering and food engineering . Continuous distillation is used widely in the chemical process industries where large quantities of liquids have to be distilled. Such industries are the natural gas processing , petrochemical production, coal tar processing, liquor production , liquified air separation, hydrocarbon solvents production, cannabinoid separation and similar industries, but it finds its widest application in petroleum refineries . In such refineries,

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2464-413: Is very seldom the case. Hence, a distillation column needs more plates than the required number of theoretical vapor–liquid equilibrium stages. Another way of improving the separation in a distillation column is to use a packing material instead of trays. These offer the advantage of a lower pressure drop across the column (when compared to plates or trays ), beneficial when operating under vacuum. If

2541-505: The McCabe–Thiele method or the Fenske equation can be used to assist in the design. For a multi-component feed, computerized simulation models are used both for design and subsequently in operation of the column as well. Modeling is also used to optimize already erected columns for the distillation of mixtures other than those the distillation equipment was originally designed for. When

2618-501: The crude oil feedstock is a very complex multicomponent mixture that must be separated and yields of pure chemical compounds are not expected, only groups of compounds within a relatively small range of boiling points , which are called fractions . These fractions are the origin of the term fractional distillation or fractionation . It is often not worthwhile separating the components in these fractions any further based on product requirements and economics. Industrial distillation

2695-515: The 1940s, Vladimir Haensel , a research chemist working for Universal Oil Products (UOP), developed a catalytic reforming process using a catalyst containing platinum . 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. The first Platforming unit was built in 1949 at

2772-452: The best naphtha for reforming are typically from Western Africa or the North Sea, such as Bonny light oil or Norwegian Troll . 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. Such

2849-464: The carbon number of the reactants remains unchanged, except for hydrocracking reactions which break down the hydrocarbons. The hydrocracking of paraffins is the only one of the above four major reforming reactions that consumes hydrogen. 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

2926-418: The catalyst can be periodically regenerated or restored by in situ high temperature oxidation of the coke followed by chlorination. Semi-regenerative catalytic reformers are regenerated about once per 6 to 24 months. The higher the severity of the reacting conditions (temperature), the higher the octane of the produced reformate but also the shorter the duration between two regenerations. Catalyst's cycle duration

3003-486: 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. 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. In many petroleum refineries, the net hydrogen produced in catalytic reforming supplies

3080-453: The column is packed with a packing material. To provide the heat required for the vaporization involved in distillation and also to compensate for heat loss, heat is most often added to the bottom of the column by a reboiler , and the purity of the top product can be improved by recycling some of the externally condensed top product liquid as reflux . Depending on their purpose, distillation columns may have liquid outlets at intervals up

3157-428: The component(s) with lower boiling point(s), vaporizes and rises. However, as it rises, it cools and while part of it continues up as vapor, some of it (enriched in the less volatile component) begins to descend again. Image 3 depicts a simple continuous fractional distillation tower for separating a feed stream into two fractions, an overhead distillate product and a bottoms product. The "lightest" products (those with

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3234-416: The components. Some example trays are depicted in image 5. A more detailed, expanded image of two trays can be seen in the theoretical plate article. The reboiler often acts as an additional equilibrium stage. If each physical tray or plate were 100% efficient, then the number of physical trays needed for a given separation would equal the number of equilibrium stages or theoretical plates. However, that

3311-423: The composition of the vapor above the liquid differs from the liquid composition. If this vapor is then separated and condensed into a liquid, it becomes richer in the lower boiling point component(s) of the original mixture. This is what happens in a continuous distillation column. A mixture is heated up, and routed into the distillation column. On entering the column, the feed starts flowing down but part of it,

3388-406: The continuous process to another steady state again. Since a continuous distillation unit is fed constantly with a feed mixture and not filled all at once like a batch distillation, a continuous distillation unit does not need a sizable distillation pot, vessel, or reservoir for a batch fill. Instead, the mixture can be fed directly into the column, where the actual separation occurs. The height of

3465-418: The conversion of normal octane to 2,5-dimethylhexane (an "isoparaffin"): The dehydrogenation and aromatization of paraffins to aromatics (commonly called dehydrocyclization) as exemplified in the conversion of normal heptane to toluene: The hydrocracking of paraffins into smaller molecules as exemplified by the cracking of normal heptane into isopentane and ethane: During the reforming reactions,

3542-420: The crude oil distillation is often further distilled to produce a "light" naphtha containing most (but not all) of the hydrocarbons with 6 or fewer 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

3619-500: The crude oil distillation towers in oil refineries ). In those cases, if the distillate product is insoluble in water, the reflux drum may contain a condensed liquid distillate phase, a condensed water phase and a non-condensible gas phase, which makes it necessary that the reflux drum also have a water outlet stream. Beside fractional distillation, that is mainly used for crude oil refining, multicomponent mixtures are usually processed in order to purify their single components by means of

3696-446: 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 . The four major catalytic reforming reactions are: The dehydrogenation of naphthenes to convert them into aromatics as exemplified in the conversion methylcyclohexane (a naphthene) to toluene (an aromatic): The isomerization of normal paraffins to isoparaffins as exemplified in

3773-455: 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 fewer 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

3850-656: The distillation tower, a naphtha hydrotreater, usually an isomerization unit to process light naphtha, an aromatics extraction unit, etc.) which puts it out of reach for smaller (micro-)refineries. Main licensors of catalytic reforming processes, UOP and Axens, constantly work on improving the catalysts, but the rate of improvement seems to be reaching its physical limits. This is driving the emergence of new technologies to process naphtha into gasoline by companies like Chevron Phillips Chemical ( Aromax and NGT Synthesis ( Methaforming , ). Continuous distillation#Continuous distillation of crude oil Continuous distillation ,

3927-403: The distillation, and the remaining bottoms fraction is removed at the end. Because each of the distillate fractions are taken out at different times, only one distillate exit point (location) is needed for a batch distillation and the distillate can just be switched to a different receiver, a fraction-collecting container. Batch distillation is often used when smaller quantities are distilled. In

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4004-446: The feed is pumped or compressed into the column. The feed may be a superheated vapor , a saturated vapor , a partially vaporized liquid-vapor mixture, a saturated liquid (i.e., liquid at its boiling point at the column's pressure), or a sub-cooled liquid . If the feed is a liquid at a much higher pressure than the column pressure and flows through a pressure let-down valve just ahead of the column, it will immediately expand and undergo

4081-419: The feed point along the column can vary on the situation and is designed so as to provide optimal results. See McCabe–Thiele method . A continuous distillation is often a fractional distillation and can be a vacuum distillation or a steam distillation . Design and operation of a distillation column depends on the feed and desired products. Given a simple, binary component feed, analytical methods such as

4158-423: The gas-to-liquids (GTL) units. The reformate has a much higher content of benzene than is permissible by the current regulations in many countries. This means that the reformate should either be further processed in an aromatics extraction unit, or blended with appropriate hydrocarbon streams with low content of aromatics. Catalytic reforming requires a whole range of other processing units at the refinery (apart from

4235-424: The height of the column to provide good conditions for fractionating the feed mixture. Reflux flows at the middle of the tower are called pumparounds. Changing the reflux (in combination with changes in feed and product withdrawal) can also be used to improve the separation properties of a continuous distillation column while in operation (in contrast to adding plates or trays, or changing the packing, which would, at

4312-402: 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

4389-421: The length of the column as shown in image 4. Large-scale industrial fractionation towers use reflux to achieve more efficient separation of products. Reflux refers to the portion of the condensed overhead liquid product from a distillation tower that is returned to the upper part of the tower as shown in images 3 and 4. Inside the tower, the downflowing reflux liquid provides cooling and partial condensation of

4466-417: The lowest boiling point or highest volatility) exit from the top of the columns and the "heaviest" products (the bottoms, those with the highest boiling point) exit from the bottom of the column. The overhead stream may be cooled and condensed using a water-cooled or air-cooled condenser . The bottoms reboiler may be a steam-heated or hot oil-heated heat exchanger , or even a gas or oil-fired furnace . In

4543-425: 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. Many chemical reactions occur in the catalytic reforming process. All require the presence of a catalyst, almost always platinum-containing, and a high partial pressure of hydrogen. Depending upon the type or version of catalytic reforming used as well as

4620-436: The naphtha before it enters the reformer, adding to the cost and complexity of the process. Dehydrogenation, an important component of reforming, is a strongly endothermic reaction, and as such, requires the reactor vessel to be externally heated. This contributes both to costs and the emissions of the process. Catalytic reforming has a limited ability to process naphthas with a high content of normal paraffins, e.g. naphthas from

4697-443: The naphtha feedstock to a catalytic reformer is always pre-processed in a hydrodesulfurization unit which removes both the sulfur and the nitrogen compounds. Most catalysts require both sulphur and nitrogen content to be lower than 1 ppm. 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. The activity of

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4774-400: The next cut overlap because the distillation separations are not perfectly sharp. After these come the heavy fuel oil cuts and finally the bottoms product, with very wide boiling ranges. All these cuts are processed further in subsequent refining processes. A typical application for distilling cannabis concentrates is butane hash oil (BHO). Short path distillation is a popular method due to

4851-481: The overhead, the next cut is withdrawn from the side of the column and it is usually the jet fuel cut, also known as a kerosene cut. The boiling range of that cut is from an initial boiling point of about 150 °C to a final boiling point of about 270 °C, and it also contains many different hydrocarbons. The next cut further down the tower is the diesel oil cut with a boiling range from about 180 °C to about 315 °C. The boiling ranges between any cut and

4928-438: The packed column with respect to more traditional trays. Differently shaped packings have different surface areas and void space between packings. Both of these factors affect packing performance. Another factor in addition to the packing shape and surface area that affects the performance of random or structured packing is liquid and vapor distribution entering the packed bed. The number of theoretical stages required to make

5005-486: The period between required shutdowns. The latest and most modern type of catalytic reformers are called continuous catalyst regeneration (CCR) reformers. Such units are defined 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 and Axens' Octanizing process. The installation and use of CCR units

5082-405: The processes used in a petroleum refinery. The crude oil fractionator does not produce products having a single boiling point; rather, it produces fractions having boiling ranges. For example, the crude oil fractionator produces an overhead fraction called " naphtha " which becomes a gasoline component after it is further processed through a catalytic hydrodesulfurizer to remove sulfur and

5159-541: The refinery of the Old Dutch Refining Company in Muskegon , Michigan . 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

5236-405: The reforming reactions is exported for use in the other refinery processes that consume hydrogen (such as hydrodesulfurization units and/or a hydrocracker unit ). The liquid from the gas separator vessel is routed into a fractionating column commonly called a stabilizer . The overhead offgas product from the stabilizer contains the byproduct methane, ethane, propane and butane gases produced by

5313-419: The same term [REDACTED] This disambiguation page lists articles associated with the title Platforming . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Platforming&oldid=1115736539 " Category : Disambiguation pages Hidden categories: Short description

5390-404: 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

5467-423: The stabilizer is the high-octane liquid reformate that will become a component of the refinery's product gasoline. Reformate can be blended directly in the gasoline pool but often it is separated in two or more streams. A common refining scheme consists in fractionating the reformate in two streams, light and heavy reformate. The light reformate has lower octane and can be used as isomerization feedstock if this unit

5544-426: The surface of the packing and the vapors pass across this wetted surface, where mass transfer takes place. Unlike conventional tray distillation in which every tray represents a separate point of vapor–liquid equilibrium, the vapor–liquid equilibrium curve in a packed column is continuous. However, when modeling packed columns it is useful to compute a number of theoretical plates to denote the separation efficiency of

5621-428: 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

5698-406: The tower, the pressure and temperature decreases for each succeeding stage. The vapor–liquid equilibrium for each feed component in the tower reacts in its unique way to the different pressure and temperature conditions at each of the stages. That means that each component establishes a different concentration in the vapor and liquid phases at each of the stages, and this results in the separation of

5775-416: The upflowing vapors, thereby increasing the efficacy of the distillation tower. The more reflux that is provided, the better is the tower's separation of the lower boiling from the higher boiling components of the feed. A balance of heating with a reboiler at the bottom of a column and cooling by condensed reflux at the top of the column maintains a temperature gradient (or gradual temperature difference) along

5852-420: The vaporized reactants enter the first reactor. 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. To maintain the required reaction temperature and the rate of reaction,

5929-413: 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

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