What is desalter water?
A desalter is a process unit in an oil refinery that removes salt from the crude oil. The salt is dissolved in the water in the crude oil, not in the crude oil itself. The desalting is usually the first process in crude oil refining.
What is the function of desalter in CDU 1?
Figure 1 below is a schematic flow diagram of a typical CDU and, as can be seen, the desalter (colored red for clarity) is typically installed in the heat exchange train that heats the incoming crude oil before it flows through a fired heater and into the distillation tower.
How does a crude desalter work?
In the desalter, the crude oil is heated and then mixed with 5-15% volume of fresh water so that the water can dilute the dissolved salts. The oil-water mix is put into a settling tank to allow the salt-containing water to separate and be drawn off. Frequently, an electric field is used to encourage water separation.
What are the minimum and maximum amount of salt are allowed in crude oil?
The removal of salts found in the form of what we may call “remnant brine” is carried out in the desalting process. This will reduce the salt content in the crude oil to the acceptable limits of 15 to 20 PTB (pounds of salt, expressed as equivalent sodium chloride, per thousand barrels of oil).
What is the significance of desalter?
The purpose of a desalting system is to reduce the salt content of the treated oil to acceptable levels. When the salinity of the produced brine is not too high, merely ensuring that there is a low fraction of water in the oil can reduce salt content.
What is dehydration of crude oil?
Crude oil dehydration is the removal of water or water vapor from crude oil, by separating the oil from the water, often in a rotating centrifuge. Crude oil contains water that must be removed to levels that meet pipeline specifications before refining into upgraded petroleum products.
What is the need of desalter and furnace in crude oil distillation?
The purpose of crude oil desalting is to remove these undesirable impurities, especially salts and water, from the crude oil prior to distillation.
Why electrostatic dehydrator is required for crude oil?
In order to remove water and salts present in the crude oil, the desalter is used. The process of removing water present in the crude oil is known as crude oil electrostatic dehydrator. If crude oil is not desalted, then the impurities, water, and salts in the crude oil may cause maintenance and operating problems.
Why is desalting done?
What are the main parameters that affect the efficiency of the desalter?
Five parameters which are affecting the efficiency of the desalter unit are; temperature, demulsifier injection rates, wash-water injection rates, differential pressure, and electrical current.
What is smoke point of kerosene?
Kerosene vapor diffused in air (as from a lamp wick) will burn at a maximum flame temperature of 990 °C (1814 °F). In a stochiometric mixture with oxygen the flame temperature of kerosene can reach 2393 °C (3801 °F).
Why should salts be removed from crude oil before refining?
Crude oil emulsion is formed as dispersed water phase in an oil medium. The water globules are protected by an oil layer which prevents their coalescence. Both the water phase and its dissolved salt contents need to be removed because they lead to corrosion in the refinery equipment.
How much wash water is needed for crude oil desalter?
The optimum desalter temperature varies somewhat with the crude oil source. At that point, wash water is injected and mixed into the continuous flow of crude oil and the resulting oil-water emulsion then continuously enters the electrostatic desalter. The rate of wash water required is about 4 to 10 % by volume of the crude oil rate.
How big is the oil-water emulsion in a desalter?
The oil-water emulsion that enters from the bottom of the desalter through the feed line is a thorough mixture of two non-miscible liquids consisting of a continuous phase (the crude oil) and a dispersed phase (water in the form of very small droplets with dimensions ranging from 1 to 10 micrometres).
How much wash water is needed for the electrostatic desalter?
At that point, wash water is injected and mixed into the continuous flow of crude oil and the resulting oil-water emulsion then continuously enters the electrostatic desalter. The rate of wash water required is about 4 to 10 % by volume of the crude oil rate.
What happens to the water in the desalter?
The resulting larger water droplets (globules), along with water-insoluble solids, then settle to the bottom of the desalter.