91- Feather separator used in the design of separation tanks for the suction and discharge sections of compressors in large LNG project liquefaction units
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This post was last edited by luoli519 on 2023-9-27 at 14:52. In large-scale LNG projects, the compressors in the liquefaction unit are high-value core operating equipment; therefore, efficient gas-liquid separators must be used as gas-liquid separation tanks at the compressor inlet, between stages, and at the discharge end, in order to provide process purification and protection for these critical compressors. Here, taking the gas-liquid separation tanks in the inlet section, inter-stage sections, and discharge section of the large compressors in an EPC project carried out by a major domestic engineering company as an example, a design discussion is conducted using the vane separator type. Please discuss based on your own experience and technical applications regarding the gas-liquid separation tanks in the compressor inlet section, between stages, and at the discharge section of the liquefaction units in LNG plants.
This engineering company boasts strong capabilities in large-scale LNG projects both domestically and internationally, and has secured an EPC contract for a large-scale LNG project from an oil and gas company of a major Western country through partnerships with renowned foreign engineering firms. This project uses an LNG process package from a foreign company designated by the foreign owner.
This process package does not specify any clear requirements or guidelines regarding the gas-liquid separation internals used in the compressor inlet section, the inter-stage sections, and the gas-liquid separation tanks in the discharge section of the liquefaction unit. After all, since it is an EPC project, the engineering company designed it using traditional, simple gravity-settling separation tanks.
This post was last edited by luoli519 on 2017-3-13 at 20:30. The size of the separation tank calculated according to the standards for gravity-driven gas-liquid separators is very large; it is even larger than the size of the compressor unit, which poses a range of challenges related to manufacturing, long-distance transportation, and on-site installation. It is similar to the situation with the raw gas compressors, fuel gas compressors, and the gas-liquid separation tanks at the inlet sections, between stages, and at the discharge section in the process packages for PDH projects introduced by domestic enterprises back then.
This post was last edited by luoli519 on 2017-3-13 20:33. The engineering company has adjusted the plan again, opting for a screen-type separation tank in place of a gravity sedimentation separation tank. However, the size of the resulting screen-type separation tank remains large, still presenting issues related to manufacturing, transportation, and on-site installation. Separators designed according to the standards for screen-type separation tanks exhibit very poor separation efficiency, and engineers also lack sufficient confidence in the design parameters they obtain based on those standards.
The last edit to this post was made by luoli519 on 2023-9-27 at 14:53. Under the leadership of the project chief engineer, engineers from various specialties held a discussion session with our team, attended by nearly 20 technical managers. We detailed the advantages of the vane separator technology in terms of quantitative and efficient separation, high operational flexibility, equipment maintenance, and space efficiency, and recommended that the engineering company use vane separators as an upgrade to traditional screen-type components. During the meeting, the project team accepted our suggestions; we then developed an accurate technical solution for the feather separator by using our proprietary and precise dynamics separation technology to design the system platform, which was subsequently submitted to the engineering company for further approval.
Although we have extensive experience and capabilities in successfully designing, manufacturing, and delivering high-pressure gas-liquid separators with a processing capacity of several million standard cubic feet of gas per hour, it was still the first time for us to work on gas-liquid separation tanks for LNG projects that handle such large volumes of gas under these conditions.
This post was last edited by luoli519 on 2017-3-13 at 19:50. Please check the operating conditions of the first gas-liquid separation tank: 1. Operating pressure: 3.0 BarA； 2. Operating temperature: -15.0℃ ； 3. Gas flow rate: 389620 kg/h ； 4. Vapor density: 5.6 kg/m^3; 5. Vapor viscosity: 0.008 cp ； 6. Liquid phase flow rate: 32215 kg/h ； 7. Liquid phase density: 555 kg/m^3 ； 8. Surface tension of the liquid phase: 12.7 mN/m; 9. Viscosity of the liquid phase: 0.17 cp.
Now, let’s look at the operating conditions of the second gas-liquid separation tank: 1. Operating pressure: 8.0 BarA； 2. Operating temperature: 17.1℃ ； 3. Gas flow rate: 558350 kg/h ； 4. Vapor density: 14.1 kg/m^3; 5. Vapor viscosity: 0.01 cp ； 6. Liquid phase flow rate: 44,970 kg/h ； 7. Liquid phase density: 511 kg/m^3 ； 8. Surface tension of the liquid phase: 8.6 mN/m; 9. Viscosity of the liquid phase: 0.13 cp.
Now, let’s look at the operating conditions of the third gas-liquid separation tank: 1. Operating pressure: 3.1 BarA； 2. Operating temperature: -43.0℃ ； 3. Gas flow rate: 714830 kg/h ； 4. Vapor density: 4.4 kg/m^3; 5. Vapor viscosity: 0.01 cp ； 6. Liquid phase flow rate: 16680 kg/h ； 7. Liquid phase density: 573 kg/m^3 ； 8. Surface tension of the liquid phase: 15.2 mN/m; 9. Viscosity of the liquid phase: 0.19 cp.
This post was last edited by luoli519 on 2023-9-27 at 14:54. The performance data of the first gas-liquid separation tank, obtained through our calculation and design system platform for precision dynamics-based gas-liquid separation technology, are as follows: 1. Type of gas-liquid separator: G50 type vaned separator； 2. Separator diameter: 95”*244” ； 3. Separation efficiency: 4N level separation to remove liquid droplets and bubbles of 4 microns and larger in size ； 4. Operating pressure drop: not exceeding 4.5 kPa.