These units produced small quantities of unstable naphthas and large amounts of byproduct coke. Discussion of the reforming and cracking reactions. In polymerization, the light olefins propylene and butylene are induced to combine, or polymerize, into molecules of two or three. It is a highly endothermic process requiring large amounts of energy. It also produces high proportions of branched alkanes and aromatic hydrocarbons like benzene. One exemplary embodiment can be a fluid catalytic cracking process. Above 600 c, dry reforming reaction became increasingly favorable and resulted in a continual increase in the h 2 and co content and a reduction in the co 2, ch 4, and c 3 h 8 content. Ppt hydrocarbons powerpoint presentation free to view. Feed stocks are light and heavy oils from the crude oil distillation unit which are processed primarily into gasoline as well as fuel oil and light gases. Why do long hydrocarbons have higher boiling points.
Difference between thermal cracking and catalytic cracking definition. Niobium stabilized alloys in steam hydrocarbon reforming. You can find instructions for this experiment at liquid paraffin a mixture of. A family of hydrocarbons which all fit the same general formula. Commonly, this is done using a process called alkylation.
In the overall steam methane reforming smr reaction, methane reacts with steam at high temperatures and moderate pressures in catalystfilled tubes to generate synthesis gas, a mixture of. What is difference between reforming and cracking answers. Fluid catalytic cracking, or fcc, is the last step in the evolution of cat cracking processes also introduced in 1942, just like tcc or thermafor cat cracking, during the second world war in an effort to make highoctane number gasoline. Making crude oil usefulfractional distillation and cracking. Oil refining method by which crude oil converted to petroleum. Alkanes hydrocarbons containing only single covalent bonds ex. Cracking takes large hydrocarbons and breaks them into smaller ones. Minimal cracking minimal conversion 10% to 20% typical products suitable for further processing or final blending reforming, catalytic cracking, hydrocracking hydrocracking severe form of hydroprocessing break carbon.
First, crack the vapour of liquid paraffin by passing it over a heated catalyst to produce and collect a mixture of gaseous shortchain hydrocarbons. Basically, the process rearranges or restructures thehydrocarbon molecules in the naphtha feedstocks as well as breaking. Also, molecules that burn better in internal combustion motors can be made by chemical processes e. The catalytic reforming is often used in the production of, methanol, hydrogen, oxidizing and reducing gases, plastics, polymers, drugs, synthetic rubber, chemical fertilizers, ammonia etc. Catalytic cracking advantages of catalytic cracking over thermal cracking. Steam cracking is a petrochemical process in which saturated hydrocarbons are broken down into smaller, often unsaturated, hydrocarbons. The hydrocarbon molecules are broken up in a fairly random way to produce mixtures of smaller hydrocarbons, some of which have carboncarbon double bonds. It is the principal industrial method for producing lighter alkenes olefins, including ethene or ethylene and propene or propylene figure 3. Thermal cracking also known as steam cracking, is used for manufacture of ethylene. The main purpose of this technology is hydrogen production.
Cracking hydrocarbons on a microscale resource rsc education. The resultant product stream cracked product is then charged to a fractionating column where it is separated into fractions, and some of the. The interest in hydrocracking has been attributed to the increasing demand for light and middle distillates, the availability of byproduct hydrogen in large quantities from catalytic reforming, and the environmental regulations limiting sulfur and aromatic hydrocarbons in motor fuels 5. It is the principal industrial method for producing the lighter alkenes or commonly olefins, including ethene or ethylene and propene or propylene. Hydrocarbons are used mainly as fuels, solvents and lubricants. Quizlet flashcards, activities and games help you improve your grades.
The use of thermal cracking units to convert gas oils into naphtha dates from before 1920. Generally, the rate of cracking and the final products. Cracking hydrocarbons on a microscale resource rsc. Aromatisation involves reactions of the type, dehydrogenation, cyclisation, and isomerisation. Reforming rearranges naphtha hydrocarbons into gasoline molecules. Since catalyst speed upretard the rate of reaction, if cracking is carried out in the presence of catalyst the rate of desired reactions cracking of heavy hydrocarbons into gasoline range hydrocarbons can be accelerated and rate. C7c9 hydrocarbons a tmospheric gas oil kerosene diesel fuel heavy fractions lubricating oil residual or heavy fuel oil asphalt or resid boiling point range below 701400c 175275ec above above comments similar to natural gas. And this results is shown to used for carbonfree deposition conditions of steam cracking process the critical steam ratio is strongly dependent on. Steamnaphtha reforming is a continuous process for the production of hydrogen from liquid hydrocarbons and is, in fact, similar to steam. Catalytic cracking is the breakdown of large compounds into small hydrocarbons in the presence of a catalyst. The performance of hydrocarbons as fuels is improved by the cracking and catalytic reforming reactions. Cracking cracking is a procession which large hydrocarbon molecules are.
In alkylation, low molecular weight compounds, such as propylene and butylene, are mixed in the presence of a catalyst such as hydrofluoric acid or sulfuric acid a byproduct from removing impurities from many oil products. Model the industrial process of cracking larger hydrocarbons to produce smaller alkanes that can be converted into petrol. Reforming chemistry britannica encyclopedia britannica. How does it work why is crude oil both important and useless. A schematic presentation of the feedstock, products and process condition is shown in figure below. Similarly, octane can produce other hydrocarbons involving cleavage of cc bonds as. In petrochemistry, petroleum geology and organic chemistry, cracking is the process whereby. Catalytic reforming is the process of transforming c7 c10 hydrocarbons with low octane numbers to aromatics and. Revisiting its importance in the modern refinery uday t turaga. Catalytic reforming process octane number of hydrocarbons 9 paraffins polymerization and alkylation. Octane numbers are very relevant in the reforming, isomerisation and alkylation. The temperatures used for this process ranges between 475530 oc.
Cracking involves breaking up heavy molecules into lighter and more valuable hydrocarbons. More of each of these fractions can be made by cracking heavier fractions. Catalytic cracking breaks complex hydrocarbons into. In petrochemistry, petroleum geology and organic chemistry, cracking is the process whereby complex organic molecules such as kerogens or longchain hydrocarbons are broken down into simpler molecules such as light hydrocarbons, by the breaking of carboncarbon bonds in the precursors. Increased capabilities and efficient processes, were designed in the refining process, and called thermal cracking of hydrocarbons. The process can include a reaction zone operating at conditions to facilitate olefin production and including at least one riser. The pressure used for this process is around 20 atm. Purpose of catalytic reforming process to improve the octane number of the feedstock, especially of heavy naphtha. Reforming, in chemistry, processing technique by which the molecular structure of a hydrocarbon is rearranged to alter its properties. The class of chemicals based on carbon and hydrogen are called hydrocarbons. Catalytic reforming catalytic reforming is the process of transforming c7 c10 hydrocarbons with low octane numbers to aromatics and isoparaffins which have high octane numbers.
Thermal reforming alters the properties of lowgrade. This paper will deal with large scale hydrogen production in stationary plants using steam reforming. This can occur thermally as occurs during the petroleum formation process beneath the earth or through the action of a catalyst. Since catalyst speed upretard the rate of reaction, if cracking is carried out in the presence of catalyst the rate of desired reactions cracking of heavy hydrocarbons into gasoline range hydrocarbons can be. The formation of petroleum penn state college of earth. Reforming involves changing the chemical nature of hydrocarbons to achieve desired physical properties and also to increase the market value. Cracking is the cleavage of carboncarbon bonds in high molecular weight alkanes induced by heat thermal cracking or with catalysts catalytic cracking. Steam reforming or steam methane reforming is a method for producing syngas hydrogen and carbon monoxide by reaction of hydrocarbons with water. The process of breaking higher hydrocarbons with high boiling points into a variety of lower hydrocarbons that are more volatile low boiling, is called cracking or pyrolysis. The hightemperature pyrolysis of hc acetylenic intermediate stage 2. However, safety concerns by many teachers and availability of equipment in some schools mean that this key and interesting experiment is often done as a demonstration. Used in the oil and gas industry to refer to a variety of methods whereby a larger product is broken down into smaller byproducts.
It also provides the chemical industry with very important compounds such as benzene, methylbenzene, the dimethylbenzenes, ethylbenzene and cyclohexane. Catalytic cracking main incentive for catalytic cracking is the need to. Sometimes, the structures of molecules in one fraction are rearranged to produce another. Catalytic cracking is the breakdown of large compounds into small hydrocarbons using an acid catalyst. Difference between catalytic cracking and catalytic reforming. Used to increase gasoline yield and improve octane yield which improves the antiknock properties of the fuel. Partial oxidation of heavier hydrocarbons is also used to a limited extent. Feb 27, 2011 i taught this lesson with a low ability year 10 group and it was observed by a regional consultant, borough consultant and head of department and judged to be a good lesson.
Thermal cracking is the process of breaking down large compounds into small compounds at high temperatures and high pressures. Reforming or aromatisation involves the conversion of open chain aliphatic hydrocarbons and or cycloalkanes in the presence of a catalyst, into aromatic hydrocarbons arenes containing the same number of carbon atoms. Coking in steam reforming reactions was studied to find the critical steam ratio above which coking does not occur as a function of temperature and pressure at the reaction equilibrium. The primary distillation produces about 2% of the initial crude as a petroleum fraction 8carbon atom per chain the. Photo courtesy phillips petroleum company catalysts used in catalytic cracking or reforming.
Introduction to hydrocarbon free download as powerpoint presentation. Catalytic reforming is a chemical process used to convert petroleum refinery naphthas distilled from crude oil typically having low octane ratings into highoctane liquid products called reformates, which are premium blending stocks for highoctane gasoline. Cracking the hydrocarbons in paraffin to form shorter alkanes and alkenes can be done as a class practical. For example, a higher hydrocarbon c 1 0 h 2 2 splits according to the reaction. Two important processes used for this purpose are cracking and reforming. Other hydrocarbons like octane and octadecane have more complicated structures. Cracking involves the breaking of cc bonds in alkanes converts.
Cracking hydrocarbons in liquid paraffin with a catalyst. A schematic presentation of the feedstock, products and. The process is frequently applied to lowquality gasoline stocks to improve their combustion characteristics. Main chemical reactions catalytic cracking of heavy hydrocarbons into lighter unsaturated hydrocarbons saturation of the. Hydrogen from catalytic reforming of biomassderived. I taught this lesson with a low ability year 10 group and it was observed by a regional consultant, borough consultant and head of department and judged to be a good lesson. Difference between thermal cracking and catalytic cracking. Catalytic uses a catalyst to speed up the cracking reaction. Hydrocarbons hydrocarbons hydrocarbons hydrocarbons hydrocarbons iupac system of naming organic compounds iupac system of naming organic compounds naming branches as groups naming branches as groups structural isomers how many structural isomers compounds with the.
However, at 800 c, co 2 was consumed completely and carbon deposition formed via the cracking of the hydrocarbons. Mar 20, 2017 catalytic reforming process octane number of hydrocarbons 9 paraffins reforming process 10. Refining is the processing of one complex mixture of hydrocarbons into a number of. Reformer tube construction is described within which both the desired endothermic catalyzed chemical reaction and heat transfer from the reaction products to the incoming reactants are accomplished. A microscale experiment, cracking the hydrocarbons in paraffin to form shorter alkanes and alkenes. Chemical processing how oil refining works howstuffworks. Cracking breaks carboncarbon bonds to turn heavier hydrocarbons into lighter ones. In the more modern fcc units, all cracking takes place in the riser. Also obtained from catalytic cracking and catalytic reforming. Cracking, in petroleum refining, the process by which heavy hydrocarbon molecules are broken up into lighter molecules by means of heat and usually pressure and sometimes catalysts. These fractions are obtained from the distillation process as liquids, but are revaporized before cracking. Epa promulgated the petroleum refining effluent guidelines and standards 40 cfr part 419 in 1974 and amended the regulations in 1975, 1977, 1982 and 1985. Process of steam cracking steam cracking is a petrochemical process in which saturated hydrocarbons are broken down into smaller, often unsaturated, hydrocarbons.
Reforming converts the hydrocarbons in petroleum to aromatic hydrocarbons and highly branched alkanes, both of which are better automotive. Cracking, in petroleum refining, the process by which heavy hydrocarbon molecules are broken up into lighter molecules by means of heat and usually pressure. Refinery modeling aaron smith, michael frow, joe quddus, donovan howell, thomas reed, clark landrum, brian clifton may 2, 2006. A free powerpoint ppt presentation displayed as a flash slide show on id. Petroleum refinery activities start with receipt of. Here, moderate temperatures and pressures are provided for the cracking process. However, safety concerns by many teachers and availability of equipment in some schools mean that this key and. Oct 30, 2012 hydrocarbons organic compounds that contain only hydrogen and carbon.
Thermodynamic analysis of coking in the steam reforming of. There isnt any single unique reaction happening in the cracker. Ppt chapter 9 hydrocarbons from petroleum powerpoint. Chapter 9 hydrocarbons from petroleum chemistry gasoline and diesel fuel are highdemand crude oil fractions. This is the first and most basic step in the refining process, and is the precursor to cracking and reforming. The simplest hydrocarbon, methane, is made up of one carbon atom and four hydrogen atoms. This cracking continues until the oil vapors are separated from the catalyst in the reactor cyclones. The light gaseous hydrocarbons produced by catalytic cracking are highly unsaturated and are usually converted into highoctane gasoline components in polymerization or alkylation processes. The cracking and reforming of crude oil fractions presentation. Petroleum refining petroleum refining catalytic cracking. The process of breaking higher hydrocarbons with high boiling points into a variety of lower hydrocarbons that are more volatile low. The reforming process involves three separate catalytic reactors, each one taking place. In thermal cracking the higher hydrocarbons are heated to a high temperature, whereby lower hydrocarbons are formed for example, 775k. University of zagreb petroleum refining and petrochemical.
For example, crude oil can be processed cracked to. This reformer tube construction eliminates the need for a hot manifold and comprises in a coaxial tube arrangement a centrally located product tube and an outer composite wall spaced therefrom. Hydrocarbon cracking is the process whereby large and heavy hydrocarbon molecules longchain hydrocarbons are broken down up into simpler and smaller bits as light hydrocarbons shortchain hydrocarbons by the breaking a carboncarbon bonds in cracking stock. Steam reforming used for producing a mix of co and h2.
I did the demo of cracking but used the diagram as well. Steam reforming for hydrogen production reforming reactions the principal process for converting hydrocarbons into hydrogen is steam reforming 6,7 which involves the following reactions. It is the principal industrial method for producing the lighter alkenes or commonly olefins, including ethene or. Catalytic reforming catalytic reforming is a chemical process used in petroleum refineries to convert naphthas, typically having low octane ratings, into highoctane liquid products called reformateswhich are components of highoctane gasoline also known as petrol. The zeolites used in catalytic cracking are chosen to give high percentages of hydrocarbons with between 5 and 10 carbon atoms particularly useful for petrol gasoline. Feb 11, 2011 you can find instructions for this experiment at cracking hydrocarbons liquid paraffin a mixture of. Plastics are made of molecules called polymers that are very long chains of hydrocarbons. Modern living is built on crude oil this hub explains how crude oil is changed into the things we use everyday, from petrol to plastic. Thermodynamic analysis of coking in the steam reforming of hydrocarbons ju ho lee and chul soo lee dept.
Aug 29, 2002 the equilibrium constant for reaction 1 per mole of co 2 is of the order of 10 8 at 500 k, indicating that the conversion of sorbitol in the presence of water to h 2 and co 2 is highly. High octane starter to inject pace which is easily adapted for other lessons. Gasoline upgrading purpose increase the quality of feed stocks of the same boiling range as gasoline characteristics catalytic reforming converts naphthenesto aromatics produces hydrogen isomerization re. Cracking of hydrocarbons download pdf info publication number us2985695a. Cracking is the most important process for the commercial production of gasoline and diesel fuel. While they succeeded in providing a small increase in gasoline yields, it was the commercialization of the fluid catalytic cracking process in. The regulations cover wastewater discharges at over 140 refineries across the country. Korea university coke formation in steam reforming and steam cracking 1.
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