We then pass the vapor over a hot catalyst, to speed up the reaction. Also included are answer sheets covering all questions on the task sheets. The process of reforming is carried out in the presence of catalyst nalkanes burn in internal combustion engine with explosion and produce knocking but branched chain hydrocarbons burn smoothly. Benzene, toluene and xylenes are some of the main aromatic products of reforming the c6 c8 hydrocarbons from the naphtha fraction air, water and land can all be affected by refinery operations. If the cracking of a nonane molecule produces two molecules including propene. Aug 29, 2002 concerns about the depletion of fossil fuel reserves and the pollution caused by continuously increasing energy demands make hydrogen an attractive alternative energy source. In this substituted hydrocarbons worksheet, students learn how to name compounds using a table of organic functional groups and the rules for naming hydrocarbon compounds. University of zagreb petroleum refining and petrochemical. The principal reactions in catalytic reforming include dehydrogenation of naphthenes to aromatics with significant quantity of hydrogen as byproduct and cracking isomerization of nparaffins into iparaffins.
Compared to thermal cracking, catalytic cracking occurs at lower temperatures and pressures, is more selective and flexible, and incorporates a catalyst. Thermodynamic analysis of coking in the steam reforming of hydrocarbons ju ho lee and chul soo lee dept. Modification of alkanes by cracking, isomerisation and reforming. Give an example of a method by which cracking can be carried out. This is a dangerous scientific experiment and must not be attempted without skilled supervision. Thermal cracking gives mixtures of products containing high proportions of hydrocarbons with double bonds alkenes. Steam cracking plants figures 1 and 2 use a variety of feedstocks, for example. When the hydrocarbon molecules are broken up in a random way as a product a mixture of shorter hydrocarbons chains is expected. Cracking of ethane and propane to produce ethylene. Pressure and steam an interesting aspect of ethene production.
Catalytic cracking is the breakdown of large hydrocarbon compounds into small hydrocarbon molecules with the use of moderate temperatures and pressures in the presence of catalysts. Schematic diagram of a fluid catalytic cracking unit. This worksheet has 12 words in a crossword puzzle, 6 fill in the blank. Catalytic reforming is a chemical process used to convert petroleum refinery. Hydrocarbon is a molecule made from hydrogen and carbon atoms. Cracking produces the smaller hydrocarbons which make up petrol gasoline. The cracking of 1 molecule of the hydrocarbon is found to produce 4 molecules of butene, 2 molecules of propene, and 1 molecule of a different compound x. This is done with alkanes in the naphtha fraction c 6 c 10 at 500c with a platinum or aluminium oxide catalyst. Catalytic cracking processes have evolved over the years, and are an exemplary display of che. There are two good economic reasons for cracking oil fractions i there isn.
Alternatively, we can mix the hydrocarbon vapor with very hot steam. 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. Hydrocarbons examples, answers, activities, experiment. All s reserved on revision notes, images, quizzes, worksheets etc. Igcse alkanes alkenes 5 cracking alkanes exercise youtube.
Catalytic reforming is a chemical process used to convert petroleum refinery, naphthas, typically having low octane ratings, into highoctane liquid products called reformates are components of highoctane gasoline also known as highoctane petrol. Catalytic cracking reforming this process involves breaking down long chained hydrocarbons for which there is low demand into short chained molecules for which there is high demand. Cracking hydrocarbons on a microscale resource rsc. Many industrial chemical processes are taught as distinct contrasting reactions when in fact the unifying comparisons are greater than the contrasts.
This is achieved by using high pressures and temperatures without a catalyst, or lower temperatures and pressures in the presence of a catalyst. Cracking is used to convert long alkanes into shorter, more useful hydrocarbons. Making crude oil usefulfractional distillation and cracking. A mixture of the vapourised fraction and a zeolite catalyst are reacted at about 450c using a slight pressure only. The questions deal with the definition of a saturated hydrocarbon, aliphatic hydrocarbons, different molecules classified as saturated hydrocarbons, and several other topics. Explain the process of fractional distillation separating molecules according to their boiling points. For each write the correct tupac namc for cach, draw a structural diagram inc, condensed or complete 17.
Hydrocarbons cracking alkane and alkenes worksheets by. These shortchained hydrocarbons have a higher octane number and also tend to be highly branched. Alkenes along with alkanes can be produced from cracking. Cracking is considered as a very important process for it can generate coke, gas oil and. The engineers guide to plant layout and piping design for the oil and gas industries, 2018. Reforming is the process of increasing the amount of cycloalkanes and hydrocarbons containing benzene rings, to improve octane number. The process converts lowoctane linear hydrocarbons paraffins into branched alkanes isoparaffins and cyclic naphthenes, which are. Revision homework cracking hydrocarbons the production of some products of fractional distillation of crude oil, such as naphtha, fuel oil and bitumen, exceeds demand. The main purpose of this technology is hydrogen production. 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.
Describe the production of materials that are more useful by cracking. We examine steam hydrocarbon reforming and steam hydrocarbon cracking as an example of two processes that operate under different chemical reactivity regimes. The rate of cracking and the end products are strongly dependent on the temperature and presence of catalysts. Petroleum as a source of hydrocarbons by fractional distillation and cracking. All that we need to do is heat longchain hydrocarbons, so that they turn into vapor.
Steam hydrocarbon cracking and reforming journal of. Catalytic cracking and catalytic reforming are two processes used in the conversion of crude oil into useful products. A reactor tube for thermally cracking or reforming of hydrocarbons wherein a reacting layer contacting hydrocarbons is made of heat resisting steel comprising, in terms of % by weight, 0. A hydrocarbons are broken down 1 mark to produce smaller more useful molecules 1 mark. Loker hydrocarbon research institute and department of chemistry. Chemical processing how oil refining works howstuffworks. Learn the basics about the cracking of hydrocarbons and why it is done. Main difference catalytic cracking vs catalytic reforming. For example, the gas used in gas stoves and bunsen burners can be either propane c 3 h 8 or butane c 4 h 10. Cracking is the breakdown of a large alkane into smaller, more useful alkenes. Thermal management evaluation for advanced aeroengines. Students understand the properties of petroleum and where it is found. Combustion of hydrocarbons all hydrocarbons burn cleanly to form water and carbon dioxide in the presence of sufficient oxygen.
There are two good economic reasons for cracking oil fractions i there isnt enough of fuels like petrol or diesel in the. Model the industrial process of cracking larger hydrocarbons to produce smaller alkanes that can be converted into petrol. It is when big hydrocarbon molecules are broken down into smaller ones. Larger molecules condense at the bottom where it is hottest. We examine steam hydrocarbon reforming and steam hydrocarbon cracking as an example of two processes that operate under different chemical reactivity. For the love of physics walter lewin may 16, 2011 duration. Difference between catalytic cracking and catalytic reforming.
The three simplest families of hydrocarbons are known as the alkanes, alkenes, and alkynes. Mainly cracking reactions of one or more covalent carboncarbon bonds in the hydrocarbon. Chemistry scholars learn the how and why of a process that involves breaking longchain alkanes down into smaller alkanes and an alkene. Journal of catalysis 10, 277289 1968 hydrocarbon cracking reactions on nickel j. Thermal cracking gives mixtures of products containing high proportions of hydrocarbons. A hydrocarbon molecule has the molecular formula c h 3 0 6 2 and can be converted into a mixture of many smaller hydrocarbon molecules via cracking reactions. These questions represent the types of facts youll need to know when you gauge your knowledge with this quiz and worksheet assessment. Cracking produces molecules like ethene and propene which are very useful in the organic chemical industry. Hydrocarbons thermal cracking selectivity depending on. Since the hydrocarbon fuel carried by engine is limited, how to efficiently utilize chemical heat sink of hydrocarbon fuel is a key concern for thermal management of scramjet. The cracking and reforming of crude oil fractions presentation. As well as cracking to produce alkenes and lower alkanes, this advanced discussion. Cracking is a thermal decomposition process by which large alkane hydrocarbon molecules are broken down by passing them over a heated catalyst at high pressure.
They practice naming twenty substituted hydrocarbons. Which type of chemical reaction is cracking an example of. Hydrocarbons such as coal, oil and gas are used every day to provide us with energy. What are the differences between reforming and cracking in. Cracking is the most important process for the commercial production of gasoline and diesel fuel. In chemistry, it is a process of breaking down large alkane into simpler alkenes and alkanes. The petrochemical industry, pressure and steam in ethene production activity 3.
Steam reforming or steam methane reforming is a method for producing syngas hydrogen and carbon monoxide by reaction of hydrocarbons with water. A gaseous product is obtained which is flammable and which will. Catalytic reforming an overview sciencedirect topics. The cracking of a nonane molecule can produce a range of products. The reforming process involves inducing chemical reactions under pressure to change the composition of the hydrocarbon. Cracking breaks long alkanes hydrocarbons with only single bonds into shorter alkanes and short alkenes hydrocarbons with one or more double bonds. The major unification process is called catalytic reforming and uses a catalyst platinum, platinumrhenium mix to combine low weight naphtha into aromatics, which are used in making chemicals and in blending gasoline.
In addition except, catalytic cracking reactions of isomeryzation, cyclization, polymerization, dehydrogenation and others are also possible. Simply put, hydrocarbon cracking is the process of breaking a longchain of hydrocarbons into short ones. A significant byproduct of this reaction is hydrogen. Petroleumrefining of petroleumknockingoctane number. Catalytic cracking of biomassderived hydrocarbon tars or. Cracking oil fractions reaction conditions products. Cracking hydrocarbons in liquid paraffin with a catalyst resource. Cracking of hydrocarbons glencoe science chemistry concepts and applications glencoe chemistry. Hydrocarbons are organic compounds containing only hydrogen and carbon atoms. The process forms a higher proportion of branched and cyclic hydrocarbons than thermal cracking see also reforming and isomerisation below. At fuse school, teachers and animators come together to make fun.
Hydrogen from catalytic reforming of biomassderived. Cracking hydrocarbons in liquid paraffin with a catalyst. Lesson with option of differentiated resources for cracking hydrocarbon fuelsfractions. Sometimes, you need to combine smaller hydrocarbons to make larger ones this process is called unification. Naming and drawing alkynes and cyclic hydrocarbons date. Catalytic cracking in which a catalyst is employed and which produces high yields of branched and cyclic alkanes. In thermal cracking, high temperatures typically in the range of 450c to 750c and pressures up to about 70 atmospheres are used to break the large hydrocarbons into smaller ones.
The process is frequently applied to lowquality gasoline stocks to improve their combustion characteristics. Catalytic cracking of hydrocarbons uniwersytet warszawski. The principal product from catalytic reforming is called reformate, consisting of c 4 to c 10 hydrocarbons. In petrochemistry, petroleum geology and organic chemistry, cracking is the process whereby. Math worksheets a series of free igcse chemistry activities and experiments cambridge igcse chemistry. Reforming is typically utilized on lowervalue light fractions, again to produce more gasoline.
Feb 11, 2011 liquid paraffin a mixture of alkanes of chain length c20 and greater is vaporised and passed over a hot pumice stone catalyst. 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. The mechanism of catalytic cracking of hydrocarbons is ionic. Thermodynamic analysis of coking in the steam reforming of. Petrol and other fuels are produced from it using fractional distillation. Vladimir shukhov took the credit as the first person who invented and patented the cracking method in 1891. Catalytic cracking is similar to thermal cracking except. Steam hydrocarbon cracking and reforming request pdf.
Inthis worksheet, students will look at how we get energy from hydrocarbons and the issues using these fuels creates. Thermal reforming alters the properties of lowgrade naphthas by converting the molecules into those of higher octane number by exposing the materials. Galwey from the chemistry department, the queens university o belast, northern ireland received june 21, 1967. For example, a higher hydrocarbon c 1 0 h 2 2 splits according to the reaction. Nomenclature worksheet 7 naming hydrocarbons petroleum or crude oil is a mixture of hydrocarbons, which are molecules that contain only carbon and hydrogen. To solve this supplyanddemand problem, we use a process called catalytic cracking to break the long chain hydrocarbons into shorter, more useful, hydrocarbons. The hightemperature pyrolysis of hc acetylenic intermediate stage 2. The worksheet can also be found by clicking on the worksheet below. What is difference between reforming and cracking answers. Students answer each of the 10 sheets by giving the missing product name and displayed formula. Jun 15, 2016 to solve this supply and demand problem, we use a process called catalytic cracking to break the long chain hydrocarbons into shorter, more useful, hydrocarbons. Name m, e, p, b structure of hydrocarbons draw the structure of the compounds below. The petrochemical industry, the industrial production of ethene activity 2. Hydrocarbons thermal cracking selectivity depending on their structure and cracking parameters introduction 1 1 introduction production of lower olefins, like ethylene and propylene, it is a fundamental process in chemical industry for the reason that the worldwide demand for these compounds is higher than any other chemicals.
Reforming is described as the processing of straightchain hydrocarbons into branchedchain alkanes and cyclic hydrocarbons for efficien gcse. Cracking is the name for a thermal decomposition processes. For example, hexane can be cracked to form butane and. Cracking is the name given to breaking up large hydrocarbon molecules into smaller and more useful bits. Petroleum cracking, reforming of hydrocarbon chemical. Us4444732a tube for thermal cracking or reforming of. Cracking and reforming effectively increase the gasoline yield from 19% to 47%. In this worksheet, we will practice explaining the catalytic cracking of alkanes and its importance and describing the process on an industrial scale. This is done by heating the hydrocarbon in the presence of a catalyst. A cracking practical can be carried out in a school lab quite easily by using a broken pottery as a catalyst. Cracking is most often utilized to produce gasoline and jet fuel from heavy gas oils. Reforming, in chemistry, processing technique by which the molecular structure of a hydrocarbon is rearranged to alter its properties. Oil refining is the process of distilling oil and then further reforming, catalytic cracking, hydrofining, blending, and sometimes coking, hydrocracking, alkylating various fractions of the. Refineries are well aware of their responsibility to the community and employ a variety of processes to safeguard the environment.
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 reaction is strongly endothermic consumes heat. 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. Korea university coke formation in steam reforming and steam cracking 1.
Cracking and alkenes crude oil, hydrocarbons and alkanes. There isnt enough economic use for the larger hydrocarbons. Jan 25, 2010 petroleum as a source of hydrocarbons by fractional. Since reaction rate of catalytic steam reforming is. Hydrocarbon cracking reactions on nickel sciencedirect. Cracking and alkenes crude oil, hydrocarbons and alkanes aqa. Bold, simple and to the point an interesting way to teach cracking. The blend of sophisticated straight chain, branched, and aromatic hydrocarbons is precise dependent on the temp etc. This useful resource includes 10 task sheets, each with a different hydrocarbon cracking question.
Cracking and reforming reactions are quite varied in their products e. Generally, the rate of cracking and the final products. All but the hydrocracking reaction releases hydrogen which can be used in the. Hydrocarbons examples, answers, activities, experiment, videos.
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