Distilation Process

Distillation is a separation method aimed to separate mixtures. The mixture is heated, the element with the lowest boiling point in the mixture starts to evaporate first and the vapors are condensed by cooling them to the appropriate temperature. For a two component mixture this would be the end of the process. If there are more than two components in the mixture than the process can further be continued by cooling the condensing fluid to the next lowest boiling point, condensation, and so on.

For better understanding the process it is recommended to view the following movie that demonstrates salt water distillation. https://www.youtube.com/watch?v=N0f73tbGCRE

Crude oil is a mixture that contains hundreds of fractions. The crude oil is being separated in a refinery by multistep distilation processes. The multistep distilation process  allows the wide use of  crude oil  in: fuels, heating, and materials fabrication.

In the following table there is information regarding a crude oil batch that arrived to the refinery.

You are the process engineer of the main distillation tower and you have to determine the cooling temperatures for the different condensation fluids of the tower (streams 1, 2, 3), according to the specific crude oil components information given. Please determine the stream temperature according the specific batch information. The tower scheme is presented.


Choose the answer that describes your decision the best:

1 People tried to answer this question

There is no significance for the cooling fluid temperature.

Stream 1: 30°C naphtha

Stream 2: 180°C Kerosene

Stream 3: 300°C oils and waxes

The given batch cannot be separated by distillation.

Stream 1: 300°C oils and waxes

Stream 2: 180°C Kerosene

Stream 3: 30°C naphtha

1.  Badiyan Anastasia (2014-12-20 15:00:00)

I like your question. The question is related to everyday life. The information you wrote before the question and the video are useful for understanding and answering the question. The picture you added to the point on the map, relevant to the subject of the question. I suggest you to add some information about the picture (point on the map).

I added a new point on your map.

Good Luck! 

2.  Mashaal Alona (2017-12-20 15:00:00)
Feedback by Aona

Hi Eilam,

The question you created is interesting, require a high cognitive level of thinking, written with no English mistakes and is related to our everyday life – production of fuel and other useable materials.

Here is my feedback:

·        The point on the map and the picture are relevant and has a strong connection to the question, but it should provide additional information that can help the student answer the question, and it should include an original movie, related to this extra information, and connects the question to the student’s everyday life. Your information point doesn’t include all that. My suggestion is to move the information you wrote about distillation from the question itself to the information point, add a little bit more information about crude oil distillation and its products, and create a short movie that shows the oil refineries in Haifa.

·        According to the assignment instructions the question should include a simulation or animation. You included a movie which is very nice, but in my opinion is too long.
I found the following nice animation/simulation which you might want to use:


·        The structure of a distillation tower is not really clear in your question. Personally I know and understand the general structure from my previous knowledge, but I think a 7-9th grade student will find it hard to figure out if not illustrated and explained in more details. My suggestion is to include a better picture (like the one in the simulation I suggested or the one here: http://www.bbc.co.uk/schools/gcsebitesize/science/aqa_pre_2011/rocks/fuelsrev3.shtml for example..) and include it in the information point.

·        The question you asked about the distillation process requires high level of cognitive thinking, maybe even too high for young students. Consider asking a different question.


I added a point on the map which talks about a very basic and natural distillation process in nature – the evaporation of the sea saline water and the creation of rain drops which are actually distilled water.

Good Luck!


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