Water Content by Distillation

RESERVOIR ENGINEERING LAB REPOR

Yasir Abdalla Hassan Aboud HemakkeshaArumugamYassine Lekhlidi

Al3KP0139A13KP0032A13KP4005

yasser_a11@hotmail.comhemakkesha@gmail.comlekhlidi.yassine@gmail.com

EXPERIMENT 8: Water Content by Distillation

SECTION : 03

GROUP : E

Water Content by Distillation1.0 OBJECTIVE:To determine the percent of water content in crude oil, tar or other crude oil derivatives by using Dean-Stark Distillation-Extraction.2.0 APPARATUS:

Dean-Stark Apparatus

3.0 MATERIAL:

Solvent, toluene or petroleum spirit ( 100-200 oC bp ), Oil samples

4.0 THEORY:In this experiment, the oil sample and an immiscible solvent in the Dean-Stark apparatus is heated until it boils. Evaporated water and the solvent being cooled by condenser to form water and solvent again. The water and the solvent are collected in a graduated cylinder. Water content in any petroleum product is very important to determine the purity and safety and also compatibility of the product in its usage, such as being used in refinery and others.The physical properties and exact chemical composition of crude oil varies from one locality to another. The different hydrocarbon components of petroleum are dissolved natural gas, gasoline, benzene, naphtha, kerosene, diesel fuel and light heating oils, heavy heating oils, and finally tars of various weights (eg: tar and pitch). The crude oil is usually sent from a well to a refinery in pipelines or tanker ships. The hydrocarbon components are separated from each other by various refining processes. In a process called fractional distillation petroleum is heated and sent into a tower. The vapours of the different components condense on collectors at different heights in the tower. The separated fractions are then drawn from the collectors and further processed into various petroleum products. One of the many products of crude oil is a light substance with little colour that is rich in gasoline. Another is a black tarry substance that is rich in asphalt. As the lighter fractions, especially gasoline, are in the greatest demand, so-called cracking processes have been developed in which heat, pressure, and certain catalysts are used to break up the large molecules of heavy hydrocarbons into small molecules of light hydrocarbons. Some of the heavier fractions find eventual use as lubricating oils, paraffins, and highly refined medicinal substances such as petrolatum.

The Dean-Stark distillation apparatus works as follows in this reaction:

As the reaction proceeds, it produces water. Water and toluene azeotrope - i.e. they will boil off as a single fraction and at a lower temperature than toluene alone. Water is denser than toluene. When the water-toluene mixture condenses in the Liebig, it flows into the Dean-Stark trap and the water sinks because it is denser than the toluene. Hence, the toluene overflows back into the reaction vessel, but the water is removed remains trapped and is removed from the reaction vessel. By Le Chatelier's Principle, this pushes the equilibrium position of the reaction so as to oppose the loss of water - it forces it towards completion - hence increasing the yield.

5.0 PROCEDURE:

1. 100 ml crude oil sample and 100 ml solvent was measured by using graduated cylinder.

2. The crude oil and the solvent were mixed into the Dean-Stark apparatus.

3. 5-10 glass beads were put into the apparatus to avoid oil to boil up out of the apparatus.

4. The apparatus was put on an electric heater.5. Retort stand has been used to hold the apparatus.6. The apparatus was assembled as in figure 1.

7. The water was flow through the condenser.

8. The sample was heated and regulated the heat such that the liquid drop is around 3 drops per second.

9. The sample was heated until the collected water volume does not change with time.10. The condenser was rinsed with solvent to collect the water on the inner condenser wall.

11. The reading of the water volume was taken in the graduated tube water collector.

6.0 RESULT:

Sample

: Crude oil

Solvent type: Petroleum spirit

Collector size: 0.1 2.0 ml

Time(min)Collected water volume(ml)ObservationNote

50.10Slightly increase from the initial valueWater collected

100.12Slightly increasedWater content in oil increasing when it distilled

150.12Start to constantWater volume are constant collected

200.12ConstantWater volume are constant collected

250.12ConstantIt reach saturation point

300.12Still constantAt certain time all water is evaporated

Measurement of Water Volume

Sample volume = 100 ml

Water volume collected = 0.12ml

= 0.12% ml7.0 DISCUSSION:7.1- State two other methods to determine water content in oil

There are two other methods that can be used in determining the water content in oil, which are Retort Distillation Method and Centrifuge Core Cleaning. Retort method is one of the most popular means of measuring the initial saturations. This method uses a small rock sample and heat the sample so as to vaporize the water and the oil, which is condensed and collected in a small receiving vessel. However this method has several disadvantages. Firstly, in this method, it is necessary to approach the temperature of 1000 to 1100oF in order to remove all of the oil. At these temperatures, the water of crystallization within the rock is driven off, causing the water-recovery values to be greater than the interstitial water.

The second error which occurs from retorting samples is that the oil itself when heated to high temperatures has a tendency to crack and coke. This change of a hydrocarbon molecule tends to decrease the liquid volume and also in some cases coats the internal walls of the rock sample itself. Thus a fluid correction must be made on a sample data obtained with a retort. Before retort can be used, calibration curves must be prepared on various gravity fluids to correct for the losses from cracking and coking with the various applied temperatures.

Second method to determine water saturation is centrifuge usage. In this method, a solvent is injected into the centrifuge just off the center. Owing to centrifugal force it is thrown to the outer radii, being forced to pass through the core sample. The solvent removes the water and oil from the core. The outlet fluid is trapped, and the quantity of water in the core is measured. The use of this centrifuge provides a very rapid method because of the high forces which can be applied.

7.2- Why solvent is used in this experiment?

Solvent is used in this experiment because the solvent can separate the water from the oil. Moreover, in the presence of the solvent, it will be functioning as a molecule separator to separate oil and water molecule.

7.3- List down several problems if crude oil were polluted with water?

1. The quality of crude oil will be low down.

2. If the crude oil is used in vehicle, it will cause the damage of the engine.

3. The crude oil will reduce the efficiency of the machine also will affect with rust.

8.0 PRECAUTIONS

8.1. The observers eyes must be in the same level as the meniscus when taking the

reading8.2. The anti-bumping must be put into the oil mixture (sample) around 5-10 glass beads to avoid the excess boiling while the experiments..

8.3. Regulate the heat carefully such that the liquid drop is around 3 drops per second.

8.4. Make sure that the water flows in is enough to equilibrium the temperature in the condenser.

9.0 CONCLUSION

In this experiment, the water volume collected from 100ml sample is 0.12ml. So the percentage of the water content in the crude oil used is 0.12%. This means that a quality crude oil contained low water content.EXECUTIVE SUMMARY

Experiment Water Content by Distillation is the second experiment we have done in reservoir engineering lab. For that, we used Dean-Stark Distillation-Extraction to determine the percent of water content in crude oil. Before we start doing the experiment, we have to read the procedure about how to handle the equipment. Although we have read that procedure but we also find some difficulties to handle the equipment. Then, we were guided by the laboratory staffs. They teach us how to handle the equipment in a proper way. It helps us to finish up the experiment successfully.

Each person in our group contributed themselves when doing this experiment very well. Where, we divide our work like one person is responsible to take the time by using stop watch. Another person has to handle the water flow, following with the next person that has to regulate the heat such that the liquid drop is around three drops per second and the last person has to write the measurement.

In this experiment, the oil sample and immiscible solvent in the Dean-Stark apparatus is heated until it boils. Then, evaporated water and the solvent were cooled by the condenser to form water and solvent again. The water and the solvent are collected in a graduated cylinder. For that, we collect all the data that we get form the experiment to do calculation. In calculation, we have to substitute the value that we obtain from the experiment in the formulae to get the percentage of water content in that oil.

From this experiment, we had learned how to handle the Dean-Stark apparatus correctly. At the same time, we also know how to calculate the percentage of water content that obtain in the oil that we tested. Last but not least, we also learn to work in the group like mentioned earlier where we divide the works. Co-operation among group are very important to make the experiment successful.

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