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