Preliminary purification of the gas-liquid stream from hydrocarbon condensate, water and mechanical impurities

The paper discusses the process plan of the piston compressor package as well as the design of the gas separator. A technical proposal has been developed to improve the preliminary purification of the gas-liquid stream from hydrocarbon condensate, water and mechanical impurities. With the help of modern computer technologies, the design of the inlet device in the separator has been developed. The operation of the gas separator was simulated after the application developed by the devices. With the help of the program, the results of the study of the gas separator operation are presented.


Introduction
The movement of oil to the well in the oil reservoir occurs due to the pressure difference in the reservoir and directly in the well.Formation-pressure maintenance (FPM) is called the process of natural or artificial preservation of this difference.The traditional method of FPM is pumping water into the reservoir, the so-called flooding.But it is also possible to use gas.Its injection into the gas cap of the field allows you to maintain pressure in the oil reservoir, which decreases as the deposit is depleted.If there is no gas cap at an oil field, then its artificial formation in the upper part of the productive horizon is possible.
The decision on the choice of FPM technology is made taking into account geological and economic factors.For example, reverse injection of gas may be justified in the development of fields with a high gas factor, where a large amount of associated petroleum gas (APG) is inevitably produced together with oil.If there is no infrastructure for transporting gas from the field, injection into the reservoir can become one of the few effective rational ways to dispose of APG.Gas injection also looks like a convincing solution in cases when there are no available water sources for traditional flooding at the field.
To implement gas injection into the reservoir, gas compressor stations are being built at the oil fields under development, where APG is compressed to the required pressure for injection.Most often, a sufficiently high gas pressure is required, reciprocating compressor packages cope well with this task.
Gas separators play a primary role in the normal operation of the entire plant, as they are necessary for the purification of natural gas (APG) from hydrocarbon condensate, water and mechanical particles before each compressor compression stage.
When the condensate is carried away by the gas, it enters the cylinder cavity and can cause the formation of a liquid film.This can lead to a water-washing effect where the water is mixed with the working gas and can cause damage directly to the compressor mechanisms.The occurrence of a water-washing effect leads to an increase in the likelihood of rod failure, which in turn causes an emergency stop of the entire piston installation.Such emergency shutdowns require long downtime and restoration work, which negatively affects the productivity and economy of the entire plant.
Attention is drawn to the need to improve the quality of pre-treatment of the gas-liquid stream.This will improve the operation of the main cleaning elements and the entire plant as a whole.More efficient pre-treatment with a gas separator will allow more efficient removal of hydrocarbon condensate, water and mechanical particles from the gas before it is fed to the next stages of purification and compression.
As a result of increasing the efficiency of the separator, the risk of water-washing effect can be reduced, and, therefore, the likelihood of rod failure and emergency shutdown of the entire plant.This reduces downtime and ensures more stable and productive operation of the entire piston unit.
Thus, improving the quality of the pre-treatment with the gas separator contributes to improving the efficiency and safety of the entire plant, which is important for its normal operation and ensuring the continuity of the APG compression process.

Technical proposal
The object of the researching is a gas separator G-1-1000-16-2,9.Vertical gas separator is designed to separate gas from liquid in oil and gas transportation or treatment system.It is used to remove gas that may be present in the liquid phase to ensure efficient system operation and prevent equipment damage.The vertical gas separator has a vertical flow direction, which allows more efficient separation of gas and liquid due to gravitational force.Vertical gas separator has three zones: attenuation zone, separation zone and collection zone.In the attenuation zone, the velocity of the gas and liquid is reduced to allow for preliminary separation of larger liquid droplets.Then, in the separation zone, further phase separation occurs, where smaller droplets and gas bubbles rise up and heavy liquid particles settle down.Finally, the separated gas and liquid leave the separator through separate outlets.
Advantages of using vertical gas separators include compactness, high efficiency of gas-liquid separation, and possibility to adjust operational parameters.They can be used in a number of industrial areas, including the oil and gas industry, the chemical industry and other processes that require gas and liquid separation.The principle of its operation is as follows: associated petroleum gas enters the separator case 1, as shown in Figure 2, through the gas-liquid inlet pipe 2 and enters the gas-liquid inlet diverter 3, where the axial flow is redirected from the gas-liquid pipe 2 to the radial direction.
After that, the gas enters the mist extractor 4, where the liquid and solid phases are separated from the gas.The liquid from the mist extractor flows down to the bottom of the vessel 7 through the drain tube 6 and after filling to a certain level is removed from the separator through the liquid outlet pipe 8.
The purpose of this study is to provide an effective gas-liquid stream pre-treatment device to improve separator efficiency and reduce the likelihood of liquid re-entrainment by the gas stream.The developed device will consist of various components.This will make it possible to use both gas and liquid efficiently, increasing the performance of the system, as well as reducing operating costs and increasing safety of operation.During the study, experiments and simulations will be carried out, as Figure 2. Gas separator G-1-1000-16-2.9: 1 -separator case; 2 -gas-liquid inlet pipe; 3 -gas-liquid inlet diverter; 4 -mist extractor; 5 -gas outlet; 6 -drain tube; 7 -bottom of the vessel; 8 -liquid outlet pipe.
In the initial version of the design, a bump plate is installed in front of the inlet pipe.Due to its inefficient operation, local overloads of the mist extractor occur, which leads to the disruption of drops and carry them away with the flow, which is extremely unacceptable for the operation of a reciprocating compressor.The flow propagation in the radial direction does not occur smoothly with a gradual change, but abruptly [1].
It is proposed to use a gas-liquid inlet diverter installed inside the apparatus opposite the gas inlet pipe.This device makes it possible to achieve a more uniform distribution of the injected medium across the cross section of the device and reduce the load of the mist extractor.This effect is achieved due to the presence of deflectors and narrowing of the passage section as it moves away from the inlet pipe of the medium.The gas-liquid inlet diverter designed using the COMPASS-3D CAD is shown in Figure 3. Using the "SolidWorks Flow Simulation" program, the flow of methane (which makes up the main share of associated petroleum gas) through the designed flow distributor was simulated.
For the simulation, the necessary parameters of static pressure equal to P = 1.6MPa and mass flow rate of gas G = 10.34 kg/s were set.The result is shown in Figure 4.

Conclusion
Based on the obtained data and the visual picture, it can be concluded that the use of a gas-liquid flow distributor system contributes to a more uniform distribution of the gas flow across the cross-section of the device.
This effect is achieved by the special design of the gas-liquid flow distributor, which equivalently distributes the gas and liquid phases within the device.This makes it possible to achieve a more uniform redistribution of the gas and liquid flow, preventing the occurrence of zones with an increased liquid concentration.
It is also worth noting that the installation of a gas-liquid flow distributor contributes to a more efficient use of the available space inside the device.Due to this, it is possible to reduce the size of the device itself, which in turn saves cost and operating costs.

Figure 4 .
Figure 4. Result of the simulation