Measurement of salt in crude oil

The salt in crude oil is due to the presence of salt water that flows from the well along with the oil, and the same amount of salt, if too high, causes the oil to be unsuitable for export and damages the separation devices in separation units and refineries.

The amount of salt in crude oil is usually adjusted to take into account the total amount of salt used, which is not more than a certain amount (8 pounds per thousand barrels). For this purpose, it is necessary to test the exploited oil in both exploitation units and chemical laboratories. Special methods have been proposed internationally for salt testing.

 

1- Salt measurement method with IP chemical solutions:
In this method, because most of the required solutions are prepared with precise chemical solutions, it is done in chemical laboratories related to oil.

2- Quick start method for measuring oil salt with FLAME PHOTOMETER:
This method is used in factories because it is simple and a maximum of 16 pounds of salt can be easily determined with this device. Prior to this amount of salts could not be tested with this device due to the high concentration and the possibility of needle clogging.Crude oil salt measuring device is one of the laboratory equipments used in oil and gas laboratory

Chemicals:

1- Toluene
2- Alcohol acetone
3- Ferric alum
4-
Amine alcohol 5- Nitric acid 30%
6- Silver nitrate N / 20
7- Thiocyanate N / 20

Required test equipment:
1- Separator
2- Two burettes
3- 100 ml graduated cylinder
4- Filter paper

Objective:

In this experiment, the aim is to measure the amount of sodium chloride (NACL) in crude oil or other petroleum products. In this method, crude oil is boiled with distilled water and suitable solvents (such as toluene) to absorb salt. And the amount of salt is calculated and reported in terms of sodium chloride.

Method of work:

Weigh 80 g of the sample into a 250 ml glass jar and heat to 60 ° C (140 ° F). Heat CC 40 toluene to the same temperature and pour it gently on the sample with stirring, then enter this solution into the distillation vessel and wash the sample container twice with CC 15 toluene heated in the above conditions and distill into the distillation vessel.

Pour 25 cc of alcohol and 15 cc of hot acetone on the sample in a distillation vessel before cooling and boil the mixture for 2 minutes. Then allow the mixture to cool and separate, then pour the bottom layer of water into a glass jar and, if necessary, pass it through Whatman 41 filter paper. This value should be around CC160.

Now pour CC 100 of the filtered solution into a glass container and after adding CC5 nitric acid, close the lid of the container and boil it and test it on the produced vapors to remove SH2 with paper impregnated with lead acetate. Continue to do so until SH2 is present in the resulting vapors (if hydrogen sulfide is in solution, the filter paper will darken and the heating will continue until the paper impregnated with lead acetate in the vicinity of the resulting vapors is discolored).

Now cool the contents of the glass jars and pour distilled water into the cap flask and add CC100 amyl alcohol and CC 3 ferric alum reagent. Bring it under the boot and shake vigorously for a few seconds to collect the resulting sediment.

To remove a lot of silver nitrate, the resulting solution should be gently titrated with potassium thiocyanate N / 20 to form a red brick color, then close the lid and shake vigorously and continue the titration operation until the red color of the brick remains constant. Perform the above test for more accuracy on 80 g of a salt-free sample (distilled water – toluene) as a control.

Note: Due to the toxicity of toluene vapors and other consumable solutions, ventilators should work during operation.
1- Adding toluene to separate oil molecules from water.
2- Adding alcohol to lower the boiling point is soluble.
3- Adding acetone to dissolve waxy substances.
4- Adding nitric acid to create an acidic environment.
Usually in the laboratory, the amount of salt is calculated and reported in pounds per thousand barrels or grams per cubic meter, for which the following formulas can be used:

Pounds of sodium chloride per thousand barrels

NACL LB / 1000 BBL = 32760 G (V) N / W

G of sodium chloride per cubic meter

GR/M3NACL = LB / 1000 BBL * 2085301

Also, to speed up the work per pound per thousand barrels of oil, the volume of silver nitrate and potassium thiocyanate is multiplied by 16.4, or for grams per cubic meter, the difference is multiplied by 47, and the result is reported directly.

Basics of physical oil salt measuring device:

Air and gas light through the mixer tube (MIXER CHAMBER) causes the impellers to rotate and in addition gas and air are mixed together. A suction state is created in the mixing tube and causes the oil to be drawn into the mixing tube through the suction needle (AUTOMIZER). Oil and gas are mixed together and a yellow flame is formed by burning the salt in the oil. The flame generated is reflected by a number of concave mirrors and a convex lens on both sides of the light-to-electrical energy conversion chamber (PHOTOCALL).

Because the created flame has different lights, and by placing a number of sodium plates in front of the converter chamber, and considering that the plate only allows the passing of yellow light, which is the result of burning salt, and after the light collides The yellow is converted to light-converting chamber to electrical energy and is directed to the galvanometer.

This device has a metal reflector which is located inside the magnetic field resulting from the above current and due to the increase and decrease of electricity, it gives rotational motion to the metal reflector and on the other hand a normal light shines on this reflector and The reflection of this light shines on the flat mirror, which is directly in front of the galvanometer, and this mirror shines on the calibrated screen mounted on the photometer film device, thus determining the amount of salt or displacement of the light spot on the calibrated screen.

it is possible . The galvanometer device has a sensitivity screw (SENSITIVITY) which is adjusted by the salt sample (standard oil) on the standard salt number and the tested oil is measured relative to the standard sample. Because the galvanometer device is very sensitive, so turn the adjusting screw on the side of the device to the FREE side when working and put it on the lock (LOCK) after finishing the work.

The above action causes the reflector of the galvanometer device to be locked and the film will not be damaged by shaking the device. There is a rubber bottom pipe under the device, which should always be in a container of water.

This is because the sediment in the mixing tube is expelled in this way, and because in the mixing tube it is expelled out of this way, and because a suction state is created in the mixing tube, if the precipitating tube is not immersed in water, air It is freely drawn into the mixer.

Equipment needed to work with photometer film:

1- 50 cc glass lid cylinder for mixing oil sample
2- 16 ounce glass bottle (400 cc)
3- Crude oil with specified salt (standard) 8 pounds per thousand barrels
4- Lighter
5- Gas for fuel of the device
6- Consumption air for the device whose pressure is set between 14-16 pounds.
7- Liquid for cleaning the device (W / 16)
8- Kerosene for mixing with crude oil if the oil concentration is high.
9- Small glass container (BEAKER)