What is desalting in crude oil?
Desalting is the first refining process applied to crude oil. The process removes salt, water and solid particles that would otherwise lead to operational problems during refining such as corrosion, fouling of equipment, or poisoning of catalysts.
Why is crude oil desalting necessary?
The purpose of crude oil desalting is to remove these undesirable impurities, especially salts and water, from the crude oil prior to distillation. The salt content in the crude oil varies depending on source of the crude oil.
What do you mean by dehydration and desalting of crude oil?
Desalting of Crude oil means the removal of the dissolved salt in the crude oil and increasing the grade of the crude oil. Crude oil dehydration is the process of removing the water present in crude oil to meet the purchaser’s limit.
What do you mean by pretreatment of crude oil?
As a first step in the refining process, to reduce corrosion, plugging, and fouling of equipment and to prevent poisoning the catalysts in processing units, these contaminants must be removed by desalting (dehydration).
Why dehydration and desalting of crude is necessary?
crude oil exists as dissolved inorganic compounds in the remnant water found in the oil. This remnant water is known as brine. These salt drops are dispersed within the oil. It presents serious corrosion and scaling problems and must be removed by desalting.
What is dehydration of crude?
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 suitable voltage for the desalting process?
Voltage within the desalter is 16,000 to 30,000 volts AC. Such a high voltage provides the coalescing force, whereas electric current has no participation on this effect. Crude oils that are highly conductive require more power to achieve coalescence.
What is crude oil treatment process?
There are three different processes that can be used: thermal cracking, hydrocracking or catalytic cracking. Converts: residual oil to fuel oil, diesel, petrol and naphtha. Converts: gas oil to petrol. Converts: Gas oil or residual oil to diesel and petrol.
Which chromatography is used for desalting?
gel filtration chromatography
Desalting and buffer exchange use gel filtration chromatography (or size-exclusion chromatography) to separate soluble macromolecules from smaller molecules. When an aqueous solution is used to transport the sample through the column, the technique is referred to as gel-filtration chromatography.
What is the desalting process explain double stage desalting?
In the two-stage desalting system, as shown in Figure 4, dilution water is added in the second stage and all, or part, of the disposed water in the second stage is recycled and used as the dilution water for the first desalting stage.
How is water removed from crude oil?
A process for removing water from heavy crude oil uses an inorganic salt which is a Group IA or Group IIA metal halide or nitrate salts. The crude oil is in the form of a water-in-oil emulsion with water content of 8% (by weight) or less. The salt is stirred into the crude oil. The resulting mixture is warmed.
What is emulsion breaker?
Emulsion breakers, also known as demulsifiers, are a group of specialty chemicals used to separate emulsions of water-in-oil and oil-in-water (reverse emulsions). These chemicals are used for effective oil recovery, and to improve the quality of reusable water.
What are the six components of crude oil?
On average, crude oils are made of the following elements or compounds:
- Carbon – 84%
- Hydrogen – 14%
- Sulfur – 1 to 3% (hydrogen sulfide, sulfides, disulfides, elemental sulfur)
- Nitrogen – less than 1% (basic compounds with amine groups)
What is the purpose of a desalting column?
Desalting columns are used with both proteins and nucleic acids. They provide a fast, simple way to purify these biomolecules away from salts and small molecules. Common uses of desalting columns include: Removal of salts.
What is emulsion in crude oil?
An oil emulsion is a mixture of oil, water, and an emulsifying agent. It contains fine water droplets dispersed in oil. In a crude oil emulsion, the quantity of water droplets is usually less than 10%. Occasionally, an emulsion occurs that contains droplets of oil dispersed in water.
How does water evaporate from oil?
If the oil layer is too thin, it may leave a hole somewhere for the water molecules to escape by evaporation. Emulsifying agents, like soap, stick to oil molecules and to water molecules, allowing the two to mix. Adding soap to water with oil on top of it may allow the water to evaporate.
What is crude oil desalting?
Crude Oil Desalting Principles of Crude Oil Desalting Desalting is an integral part of refinery crude oil processing and can be the key to controlling pipestill corrosion, heat exchanger fouling, furnace tube coking, and process water disposal.
What are the steps involved in the dehydration of crude oil?
Successful dehydration of crude oil is carried out in three steps 1 Destabilization of the emulsion 2 Coalescence of small drops into large drops 3 Settling out of large drops and separation of the two phases.
How to prevent corrosion in crude oil?
• TO AVOID CORROSION DUE TO SALTS IN THE CRUDE OIL, CORROSION CONTROL CAN BE USED. BUT THE BYPRODUCT FROM THE CORROSION CONTROL OF OIL FIELD EQUIPMENT CONSISTS OF PARTICULATE IRON SULFIDE AND OXIDE. PRECIPITATION OF THESE MATERIALS CAN CAUSE PLUGGING OF HEAT EXCHANGER TRAINS.
How does temperature affect the settling rate of heavy crude oil?
An increase in temperature causes a reduction in viscosity, therefore the application of heat can be used to accelerate the separation of heavy crude. The settling rate depends on the square of the droplet diameter.