Chemistry Of Petroleum four: Remedy Of Hydrocarbons
To introduce how petroleum fractions are chemically handled in the refinery course of to supply helpful materials.
This lesson is part of the Vitality in a High-Tech World Project, which examines the science behind power. Vitality in a High-Tech World is developed by AAAS and funded by the American Petroleum Institute. For extra lessons, activities, and interactives that take a more in-depth look on the science behind power, be certain to check out the Energy in a Excessive-Tech World Project page.
This lesson is the fourth in a sequence of classes in regards to the chemistry of petroleum which can be meant for higher-stage chemistry students in the 11th and 12th grades. Try to be an skilled chemistry teacher to teach these classes. The aim of those lessons is to introduce high-school students to using oil as an power source in immediately’s excessive-tech world. Within the Chemistry of Petroleum 1: What are Hydrocarbons students will discover hydrocarbons, the molecular foundation of petroleum, and learn to differentiate between organic and inorganic compounds.
In the Chemistry of Petroleum 2: What Occurs to Hydrocarbons Once they Burn students will examine the varying quantities of power produced by the combustion of various hydrocarbons.
Within the Chemistry of Petroleum 3: Distillation of Hydrocarbons, students shall be introduced to the distillation processes by which petroleum is refined to produce helpful petroleum fractions.
The Chemistry of Petroleum four: Remedy of Hydrocarbons will assist students explore the chemical treatment processes by which distilled petroleum fractions are transformed to provide useful gas oils.
This specific lesson is a continuation of lesson three, which taken together full the crude oil refining course of. Lesson three concludes with the crude oil being separated into petroleum fractions, primarily based on the relative boiling factors of the hydrocarbons in the unique crude oil. On this lesson, students discover how these petroleum fractions are treated chemically to produce helpful fuels that are acquainted to them, similar to diesel, jet gas, and gasoline.
As college students discover the interactive, they could also be overwhelmed with the quantity of terminology and reactions associated with the remedy process. College students do not have to know or memorize the main points of those reactions; reasonably, they should obtain a general understanding that a series of chemical reactions are necessary in producing the fuels that are used on an everyday basis.
As in lesson 3, this exercise supplies a chance to make clear the widespread misconception that crude oil is composed of particular person molecules of diesel, kerosene, and the other refined products. By the top of those classes, college students ought to understand that there isn’t any single molecule often known as diesel, or kerosene, or light gases, with a specific chemical formulation, like H2O. Fuel oils, like diesel, are a mixture of various molecules that share similar properties. The two essential properties shared in a petroleum fraction are the number of carbons in a molecule and the boiling point.
So as for students to do this lesson, in addition to the opposite lessons in this collection, they should have prerequisite information of the fundamentals of atoms and their structure. Primary details about atoms may be discovered on the Atom. Students additionally ought to know primary natural chemistry, together with an understanding of what hydrocarbons are and how they are named (i.e. nomenclature).
Begin by asking students: “We all know that petroleum is used to make gasoline. However what different merchandise are made from petroleum ” Ask college students to brainstorm in groups, each group producing an inventory of at the very least ten objects that they’ve seen or used in the past 24 hours which can be petroleum products. An inventory of items could be discovered at: Just a few Merchandise Made from Petroleum.
As scholar groups share their product objects, generate a category list. Level out that these items and lots of extra are all made with fuels derived from crude oil or petroleum. Ask college students:
– How do you suppose our use of petroleum products has modified over time
– Given the excessive buyer demand and the fact that crude oil is a restricted resource, how do you assume refineries make the most out of the crude oil they’ve
Overview with students the primary stages of crude oil refinement and therapy by making a flowchart. In the beginning of the flowchart, write the phrases “crude oil.” At the end of the flowchart, place the checklist of merchandise generated by the scholars. Begin to fill in the flowchart by asking college students what happens to crude oil once it is positioned within the earth. Subsequent steps should embrace extraction and taking the crude oil to a petroleum refinery. Once on the refinery, the crude oil undergoes the distillation process. The outcomes of distillation are petroleum fractions. Ask students, “Describe what has occurred to the hydrocarbons in the distillation course of.”
Now college students ought to assessment the Oil Refining: A more in-depth Look interactive by watching the introductory video and going by way of the distillation process. The movie has an accompanying script that you can print out. The narrator speaks quickly, so it is a good suggestion to read the script after watching the movie the first time. After reading the script, college students can watch the film a second time, which will facilitate understanding.
– What chemical property was used to separate the hydrocarbons within the distillation process
Undergo petroleum products news online the seven fractions, emphasizing that the fractions are composed of a mixture of hydrocarbons, and are usually not composed of a single molecule. For instance, kerosene is a mixture of hydrocarbon molecules from the unique crude oil that comprise between 10-sixteen carbons. Which means there are hydrocarbons within the kerosene fraction that contain 10 carbons and others that comprise eleven, and so on through 16.
Point out that by way of the distillation process, the hydrocarbons haven’t been altered or modified in any method; they have merely been separated by dimension utilizing the chemical property of boiling point differences. This is a bodily change. On the flowchart after distillation and earlier than the students’ listing of on a regular basis products and oils, write the word “therapy.” Outline for college kids that remedy is the sequence of chemical reactions and applied sciences to modify the distilled fractions to make helpful and marketable oils.
Allow students to discover the remedy section of the interactive on their own utilizing the Treatment of Hydrocarbons student esheet. College students can answer the questions utilizing the Treatment of Hydrocarbons scholar sheet. Solutions are available on the Therapy of Hydrocarbons instructor sheet. Review the questions collectively as a class. Through dialogue and evaluation of the guiding questions, explain that there are three completely different therapy processes, usually. These are:
1. Removing impurities within the hydrocarbons, akin to metals and sulfur
2. Breaking down massive, heavy hydrocarbons
3. Reshaping or constructing hydrocarbons from smaller ones
The purpose of these processes is to make useful merchandise, reminiscent of diesel, gasoline, jet gasoline, and asphalt. In the end, these closing products should not particular person molecules, but blends of treated hydrocarbons of varied lengths and structures.
Go through examples of every of the three processes. Start with the primary course of (Removing impurities in the hydrocarbons) by asking students:
– What are the two processes that are used to remove sulfur
Inform college students that the general thought behind hydrotreating is to add hydrogen fuel at high pressure and temperature to the petroleum fractions. The oil and hydrogen then enter a reactor loaded with a catalyst.
Ask college students:
– What is a catalyst
In hydrotreating, a metal floor is normally used as a catalyst. These metals embody palladium, nickel, platinum, cobalt, and iron. Draw a common reaction method for college students to understand hydrotreating.
S + H2 (g) → H2S (g)
(Catalyst, heat, and stress)
If doable, mission the remedy web page of the interactive for the class. Click on on one of the fuels and then on the hydrotreating box to point out students an example of one of many forms of reactions that occur in the hydrotreating unit. Stable sulfur is transformed to hydrogen sulfide gas, which is then removed.
S8 (s) + 8H2 (g) → 8H2S (g)
(Catalyst, heat, and pressure)
Inform college students that the hydrotreating course of additionally removes nitrogen compounds, which if not removed, would react with the oxygen within the air and produce nitric acid (HNO3).
Begin describing an example of the second process (Breaking down massive, heavy hydrocarbons) by asking students:
– Do giant hydrocarbons have high or low boiling factors Why
Write the formula for docosane on the board: C22H46, and inform college students that this large hydrocarbon is found in the gas oil fraction after distillation. The gasoline oil fraction is composed of a mixture of hydrocarbons with 20-70 carbons. If attainable, undertaking the remedy page of the interactive in entrance of the classroom and click on the crimson circle subsequent to “gas oil.” Then click on on the throbbing yellow circle within the gas oil pipe to show the chemical structure of docosane. Ask students:
– What is the first treatment process for the gasoline oil fraction
Tell college students that cracking processes break down heavy hydrocarbons (you may want to use the time period massive hydrocarbon molecules) into lighter products (smaller hydrocarbon molecules). Several types of cracking processes are used. Deal with catalytic cracking, telling students that this process makes use of high heat and a catalyst to interrupt bigger molecules into smaller, more useful ones. Draw the following response to indicate college students how catalytic cracking works:
C22H46 + heat + catalyst → C12H26 + C6H12 + C4H8
The catalyst used is commonly silica or alumina. In the above reaction, docosane is converted to dodecane, cyclohexane, and butene. The smaller hexane and butene can be combined with different smaller compounds to make gasoline inventory. The larger dodecane is a part of diesel stock, which can be used to gasoline ships and factories.
Describe an instance of the third course of (Reshaping or constructing hydrocarbons from smaller ones) by clicking the red circle subsequent to “light naphtha” on the remedy web page of the interactive. Doing so will present two therapy processes: hydrotreating and isomerization. Ask college students:
– Are the hydrocarbons in gentle naphtha giant or small relatively
Tell students that light naphtha is a mixture of mostly pentane and hexane. Have college students draw the chemical structures of pentane and hexane. If potential, present models of every construction. Ask college students:
– What is an isomer
Write the following reaction on the board:
C5H12 → C5H12
Inform students that this is the reaction for pentane to isopentane. Ask college students to attract the chemical construction of isopentane. Utilizing the mannequin for pentane, remove the fifth carbon from the chain and transfer it to the second carbon. This new structure is isopentane (additionally referred to as methylbutane or 2-methylbutane), which has the identical chemical system as straight-chained pentane. Inform students that this isomerization is necessary in the petroleum remedy process as a result of isomers enhance the quality of gasoline versus the straight-chained molecules. Actually, isomers improve the octane ranking for gasoline.
Have college students work in groups to decide on one in all the tip products of the crude oil distillation and therapy process: diesel, kerosene, gasoline, jet gas, or asphalt. Ask each group to develop a presentation that discusses how their final product is formed. As they’re doing this train, they should make certain to categorise every step as a bodily or chemical change. Their information should draw upon all points of the interactive, together with the film. Their shows ought to begin with the tiny sea plants residing hundreds of thousands of years in petroleum products news online the past and transfer by way of the strategy of forming kerogen, and in the end petroleum. Remind students to incorporate drilling before transferring into the distillation and treatment process. Students should embody a flow chart in their presentations. Encourage students to make use of completely different strategies of displaying their information. For example, college students might choose to present a storyboard, comic e book, PowerPoint, essay, or a short movie. Assess students primarily based on their holistic understanding of how useful gasoline oils are made from crude oil through a sequence of essential chemical processes.
Have college students discover what octane rankings for gasoline signify concerning the product. There are quite a lot of misconceptions that students could have. After a lesson, encourage college students to survey their mother and father, teachers, and different drivers about what they know about octane ratings of gasoline. You and your college students can overview Discovering the Science of Petrol to be taught more about octane.