Oil and gas separators are designed to extract gas released during the movement of oil through a collecting manifold, flow hole or wellbore. The scope of use of the resulting product is the chemical or fuel industry. In addition, raw materials are used to reduce hydraulic resistance in pipelines, delamination and separation of foam from the finished oil. They can significantly reduce ripple during transportation of petroleum products from tanks of the first degree to units for the preparation of full processing.
Types and differences
Oil and gas separators are divided into several conditional categories that differ in various parameters:
- Metered or conventional separators.
- The manufacturing form can be in cylindrical, spherical, vertical, horizontal and inclined versions.
- Service can be fountain, pump, compressor.
- The principle of action is gravitational, inertial or centrifugal.
- Working pressure - from 0.6 MPa (low) to 6.4 MPa (high).
- The number of wells served - single or group.
- Separation stages - from the first and higher.
- Two or three phase models. In the latter case, in addition to gas and oil, water is sorted.
Working sections
The sedimentation compartment is designed for additional release of gas bubbles, which joined the oil during the transition from the separation section. To enhance the selection, the liquid is directed in a small layer along an inclined surface, which allows to increase the selection efficiency. Inclination planes should be equipped with thresholds that facilitate the release of gas from oil.
Oil and gas separators are also equipped with discharge compartments. They occupy the lowest position in the structure, are used to collect and remove oil from the device. In this section, the product may be in a mixed or pure state. This factor depends on the efficiency of the sedimentation compartment and the period of stay of oil products in the working chamber.
In the upper part of the separator is a compartment for catching drops. It cuts off the smallest particles of liquid that are carried away by the gas stream. Any devices under consideration are characterized by two aspects: the number of droplet liquid and the number of gas bubbles carried away by the oil from the collection section. The quality of the device is considered higher with the minimum specified indicators.
Formulas for calculating the efficiency of an oil and gas separator
The efficiency of the device is calculated according to several parameters. They are determined by the following notation:
- GMH and GMK - the mass flow of oil to and from the separator.
- VK and VH are the flow rates of the supplied gases before and after treatment.
- ZHMGK (GMGK) and GMGH - total gas flow before and after the separator.
- qG and qH - the amount of drip fluid entrained from the device in the working process ( m 3 / h) .
- GH and GM are the volumes of oil and gas consumption during the operation of the separator.
- KZh and KG - specific ablation of a drop liquid and free gas, respectively.
At each stage of processing, the amount of oil decreases due to a decrease in pressure, and a similar indicator of gas increases. Such functionality corresponds to the normal operation of the installation. It is worth noting that the indicators of QOL and KG may differ depending on the type of oil and gas separators. This includes technological, economic aspects, as well as the volume of the tank and the availability of special fenders.
Principle of operation
The overall efficiency of the units under consideration in gas and oil fields is estimated mainly by the first aspect (the number of droplet mixture that is carried away by the gas outside the tank). Consequently, the requirements for oil and gas separators differ depending on the features of their design.
For example, a model with a blind-type nozzle functions as follows:
- A mixture of oil and gas is supplied through the pipe to the distribution manifold.
- It has a notch along the entire length, from which the liquid enters the inclined elements, which increase the distance of the oil products and contribute to the release of occluded gas bubbles.
- At the top of the device there is a nozzle for sorting drops, which has a different section. Oil particles are sifted out through the louvre nozzle, after which they are sent to the lower part of the unit through the drainage tube and sump .
Oil and gas separators with water discharge
Modern oil and gas separators are significantly different in terms of characteristics and functionality. However, not all of them are widely used in commercial production. In deposits that have been developed for several decades, similar devices are called gangways.
Consider a modification with a preliminary discharge of water that meets all the requirements. The unit has a preliminary gas selection and works according to the following principle:
- A mixture of oil and gas is supplied to the unit body using inclined pipelines.
- The angle of inclination is 30 - 40 or 10 - 15 degrees.
- Several vertically mounted tubes with a diameter of five to ten centimeters are welded to the second pipeline.
- The upper parts of these elements are welded to a prefabricated manifold, which supplies gas to the droplet trap.
- A perforated partition is mounted in this compartment, which serves to equalize the gas flow. It is equipped with a special louver type cassette.
- Drops of oil are carried away by the main gas stream through the collector, and the remaining masses adhere to the walls of the cassette and the blinds, accumulating on them. The result is a continuous film that drains into the bottom of the separator.
- From the droplet eliminator, the mixture is delivered to the ejector, where it is transported to a gas processing plant under a pressure of about 0.6 MPa.
Properties and Parameters
The calculation of the parameters of an oil and gas separator of almost any type includes several factors, namely:
- Properties of physicochemical characteristics of oil. In dense and viscous masses, gas bubbles separate slowly, which indicates the low efficiency of the separator, which will function with excessive entrainment of gas bubbles.
- Performance aggregates. This aspect depends on the mass lifting speed in the unit and the number of connected devices. For example, bubbles with a minimum starting speed will float to the surface, which degrades the quality of the separation process.
- Oil and gas separator type NGS allows you to increase the speed of rise of gas bubbles. This, in turn, contributes to an increase in the influence of gravitational forces, allowing to limit the rise of gas particles to the surface of the oil. They will be carried away by streams of liquid that will allow to receive the most pure product.
- Another significant factor is pressure. The higher it is in the unit, the lower the gas density and the rate of appearance of bubbles on the surface.
Features
Since oil has a tendency to foam, which is rather difficult to separate, there is no particular choice of funds for this procedure. It is quite acceptable to use silicone or a physico-mechanical cleaning method.
The final quality of the product is also affected by the design of the internal arrangement of the separators, as well as the presence of water in the produced product. The latter indicator directly affects the production of stable emulsions with a high percentage of viscosity.
Total
Based on the foregoing, it can be concluded that the purpose of oil and gas separators is to clean oil from water and gases. A number of techniques and formulas are provided for calculating the operation of devices. In terms of throughput, the operation of the device can only be calculated by vertical and gravitational activity. In many respects, the functionality of such units depends on the design features and related factors in the form of equipping with additional equipment (blinds, partitions, chippers, etc.).