Chemistry Of Petroleum four: Treatment Of Hydrocarbons

To introduce how petroleum fractions are chemically handled in the refinery course of to supply helpful materials.

This lesson is the fourth in a sequence of classes in regards to the chemistry of petroleum that are intended for higher-degree chemistry students within the eleventh and twelfth grades. You should be an skilled chemistry instructor to show these classes. The goal of these classes is to introduce excessive-faculty college students to using oil as an vitality supply in immediately’s excessive-tech world. Within the Chemistry of Petroleum 1: What are Hydrocarbons? students will discover hydrocarbons, the molecular basis of petroleum, and study to distinguish between natural and inorganic compounds.

Within the Chemistry of Petroleum 3: Distillation of Hydrocarbons, students will likely be launched to the distillation processes by which petroleum is refined to produce useful petroleum fractions.

This explicit lesson is a continuation of lesson three, which taken together full the crude oil refining process. Lesson three concludes with the crude oil being separated into petroleum fractions, based on the relative boiling points of the hydrocarbons in the unique crude oil. In this lesson, college students explore how these petroleum fractions are treated chemically to supply useful fuels which can be familiar to them, corresponding to diesel, jet gasoline, and gasoline.

As college students discover the interactive, they could also be overwhelmed with the amount of terminology and reactions related to the treatment course of. Students don’t must know or memorize the small print of those reactions; rather, they need to achieve a general understanding that a series of chemical reactions are essential in producing the fuels which can be used on an on a regular basis foundation.

As in lesson three, this activity offers an opportunity to clarify the widespread false impression that crude oil is composed of individual molecules of diesel, kerosene, and the other refined products. By the tip of these lessons, college students should understand that there isn’t a single molecule referred to as diesel, or kerosene, or mild gases, with a selected chemical system, like H2O. Gas oils, like diesel, are a mixture of different molecules that share similar properties. The two main properties shared in a petroleum fraction are the number of carbons in a molecule and the boiling level.

Start by asking college students: “We know that petroleum is used to make gasoline. However what different merchandise are made from petroleum?” Ask students to brainstorm in groups, each group producing an inventory of not less than ten objects that they’ve seen or used in the past 24 hours which can be petroleum merchandise. An inventory of objects will be discovered at: A couple of Products Made from Petroleum.

As student groups share their product items, generate a category checklist. Point out that these things and plenty of more are all made with fuels derived from crude oil or petroleum. Ask students:

– How do you think our use of petroleum products has modified over time?

– Given the high customer demand and the truth that crude oil is a restricted resource, how do you assume refineries make the most out of the crude oil they’ve?

Assessment with students the first stages of crude oil refinement and treatment by making a flowchart. Firstly of the flowchart, write the words “crude oil.” At the end of the flowchart, place the list of products generated by the students. Start to fill within the flowchart by asking students what occurs to crude oil as soon as it is positioned within the earth. Subsequent steps should include extraction and taking the crude oil to a petroleum refinery. As soon as at the refinery, the crude oil undergoes the distillation course of. The results of distillation are petroleum fractions. Ask college students, “Describe what has happened to the hydrocarbons within the distillation course of.”

Now college students should evaluate the Oil Refining: A better Look interactive by watching the introductory video and going by the distillation course of. The film has an accompanying script you could print out. The narrator speaks quickly, so it’s a good idea to learn the script after watching the movie the primary time. After reading the script, college students can watch the movie a second time, which is able to facilitate understanding.

– What chemical property was used to separate the hydrocarbons in the distillation course of?

Go through the seven fractions, emphasizing that the fractions are composed of a mixture of hydrocarbons, and will not be composed of a single molecule. For example, kerosene is a mixture of hydrocarbon molecules from the original crude oil that comprise between 10-sixteen carbons. This means that there are hydrocarbons within the kerosene fraction that contain 10 carbons and others that contain eleven, and so forth by means of sixteen.

Point out that by the distillation course of, the hydrocarbons have not been altered or modified in any manner; they have merely been separated by measurement using the chemical property of boiling level variations. It is a physical change. On the flowchart after distillation and earlier than the scholars’ listing of on a regular basis merchandise and oils, write the word “treatment.” Define for college kids that remedy is the collection of chemical reactions and technologies to change the distilled fractions to make useful and marketable oils.

Permit college students to discover the treatment section of the interactive on their own utilizing the Therapy of Hydrocarbons scholar esheet. College students can answer the questions utilizing the Therapy of Hydrocarbons 4500 square 2205 heat exchanger scholar sheet. Answers are available on the Remedy of Hydrocarbons teacher sheet. Evaluation the questions together as a category. Through discussion and evaluation of the guiding questions, explain that there are three totally different treatment processes, basically. These are:

1. Eradicating impurities within the hydrocarbons, resembling metals and sulfur
2. Breaking down giant, heavy hydrocarbons
three. Reshaping or constructing hydrocarbons from smaller ones

The aim of these processes is to make helpful merchandise, equivalent to diesel, gasoline, jet fuel, and asphalt. In the long run, these final merchandise should not particular person molecules, however blends of treated hydrocarbons of various lengths and buildings.

Undergo examples of each of the three processes. Start with the first process (Eradicating impurities within the hydrocarbons) by asking students:

– What are the 2 processes that are used to remove sulfur?

Inform college students that the general thought behind hydrotreating is to add hydrogen fuel at excessive pressure and temperature to the petroleum fractions. The oil and hydrogen then enter a reactor loaded with a catalyst.

– What’s a catalyst?

In hydrotreating, a steel floor is normally used as a catalyst. These metals include palladium, nickel, platinum, cobalt, and iron. Draw a basic response components for college students to know hydrotreating.

S + H2 (g) H2S (g)
(Catalyst, heat, and stress)

If doable, challenge the remedy web page of the interactive for the class. Click on on one of the fuels after which on the hydrotreating field to point out college students an example of one of many types of reactions that occur within the hydrotreating unit. Solid sulfur is converted to hydrogen sulfide fuel, which is then eliminated.

S8 (s) + 8H2 (g) 8H2S (g)
(Catalyst, heat, and stress)

Inform students that the hydrotreating course of also 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 course of (Breaking down massive, heavy hydrocarbons) by asking students:

– Do giant hydrocarbons have excessive or low boiling factors? Why?

Write the formulation for docosane on the board: C22H46, and tell college students that this large hydrocarbon is found within the gasoline oil fraction after distillation. The fuel oil fraction is composed of a mixture of hydrocarbons with 20-70 carbons. If potential, mission the therapy page of the interactive in front of the classroom and click on on the pink circle subsequent to “gasoline oil.” Then click on on the throbbing yellow circle within the fuel oil pipe to display the chemical construction of docosane. Ask students:

– What’s the first remedy process for the gasoline oil fraction?

Tell students that cracking processes break down heavy hydrocarbons (you may want to make use of the time period giant hydrocarbon molecules) into lighter products (smaller hydrocarbon molecules). Various kinds of cracking processes are used. Deal with catalytic cracking, telling college students that this course of uses excessive heat and a catalyst to break larger molecules into smaller, more helpful ones. Draw the next response to point out 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 mixed with different smaller compounds to make gasoline stock. The bigger dodecane is a element of diesel stock, which can be utilized to fuel ships and factories.

Describe an instance of the third process (Reshaping or building hydrocarbons from smaller ones) by clicking the red circle subsequent to “light naphtha” on the therapy page of the interactive. Doing so will show two treatment processes: hydrotreating and isomerization. Ask college students:

– Are the hydrocarbons in gentle naphtha giant or small relatively?

Inform college students that mild naphtha is a mixture of mostly pentane and hexane. Have students draw the chemical buildings of pentane and hexane. If attainable, present models of each construction. Ask students:

– What is an isomer?

Write the following reaction on the board:

C5H12 C5H12

Tell college students that that is the response for pentane to isopentane. Ask college students to draw 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 (also known as methylbutane or 2-methylbutane), which has the same chemical system as straight-chained pentane. Inform students that this isomerization is important in the petroleum therapy course of as a result of isomers enhance the standard of gasoline as opposed to the straight-chained molecules. In fact, isomers enhance the octane ranking for gasoline.

Have college students work in groups to decide on one among the tip merchandise of the crude oil distillation and remedy course of: diesel, kerosene, gasoline, jet fuel, or asphalt. Ask every group to develop a presentation that discusses how their ultimate product is formed. As they are doing this exercise, they should ensure to categorise each step as a physical or chemical change. Their information ought to draw upon all points of the interactive, including the film. Their presentations ought to start with the tiny sea plants living hundreds of thousands of years ago and move via the means of forming kerogen, and ultimately petroleum. Remind college students to incorporate drilling before shifting into the distillation and remedy course of. College students ought to include a stream chart in their displays. Encourage students to make use of completely different methods of displaying their info. For example, college students might select to present a storyboard, comic e book, PowerPoint, essay, or a brief film. Assess college students based on their holistic understanding of how useful fuel oils are made from crude oil via a collection of essential chemical processes.

Have students explore what octane rankings for gasoline signify about the product. There are a variety of misconceptions that students might have. After a lesson, encourage college students to survey their parents, teachers, and different drivers about what they find out about octane rankings of gasoline. You and your students can overview Discovering the Science of Petrol to study more about octane.

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