47- Issues in the design of power-sail type separators for pre-cooling and separation tanks at the top of distillation towers and acidic gas absorption and regeneration towers
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This post was last edited by luoli519 on 2023-10-3 12:10. In petrochemical plants, MDEA or low-temperature methanol liquid-phase absorption is commonly used to desulfurize and decarbonize process gases. The resulting rich liquid is regenerated through distillation in a regeneration tower. In foreign process packages, it is generally required that the primary pre-cooling and separation unit at the top of the regeneration distillation tower use a power umbrella-type separation tank. In fact, in the primary pre-cooling and separation tank at the top of distillation columns containing inert gases, a powered umbrella-type separation tank is required. Many domestic design firms and clients have little understanding of the powered parachute-type separation tank and its functions. Let’s all discuss together what the structure of a paraglider-type separation tank is What impacts will design issues in the paraglider-type separation tank have on the process?
For distillation systems containing non-condensable gases, including atmospheric and vacuum distillation columns, the process design typically involves two stages of condensation for the vapor at the top of the column: a first stage of pre-cooling and a second stage of deep cooling.
Adopt step-by-step cooling and condensation. During the first stage of pre-cooling, the vapor taken from the top of the distillation tower passes through a heat exchanger, where most of the condensable gases are converted into liquid condensate; it is necessary to carry out efficient gas-liquid separation of the non-condensable gas and the liquid condensate ； The separated gas phase then enters the second-stage cryogenic heat exchanger.
This post was last edited by luoli519 on 10:43, 2016-11-8. Due to the large amount of condensate generated in the first-stage precooling, along with the non-condensable gases, a mixed flow is formed in the heat exchanger; therefore, it is necessary to use a dynamic umbrella-type separation tank to effectively separate this gas-liquid mixture coming out of the first-stage precooler. Its functions include, first, preventing the liquid streams, droplets, and foam carried by non-condensable gases from causing accumulation and \"liquid resistance\" in subsequent pipes, which would lead to pulsatory flow of the gas stream and unstable operating pressure in the system; this effect is particularly severe in vacuum distillation. Secondly, crime prevention measures prevent the gas from carrying a large amount of liquid into the second-stage cryogenic heat exchange equipment; as a result, the liquid carried in from upstream not only consumes a significant amount of refrigerant energy but also increases the heat transfer resistance. This makes it difficult for the gas to condense further in the second-stage cryocooler, causing the desired components to enter the downstream extraction system, which reduces the yield and increases the costs associated with post-treatment.
The last edit to this post was made by luoli519 on 10:43, 2016-11-8. Below are the technical requirements for the process equipment of the primary power-sail type pre-cooling and separation tank at the top of the regeneration distillation tower in an EO/EG project of a large petrochemical company: 1. Type of the primary pre-cooling and separation tank at the top of the regeneration distillation tower: power-sail type separation tank； 2. Layout method: Horizontal ； 3. Process medium: mainly the large amount of CO2 and water extracted from the regeneration tower ； 4. Gas flow rate: 23,040 kg/h ； 5. Average molecular weight in the gas phase: 25.13. 6. The liquid phase is water ； 7. Operating temperature: 96℃ ； 8. Operating pressure: 0.02 MPaG; 9. Maximum allowable operating pressure difference: 0.002 MPa ； 10. Maximum liquid flow rate: 4000 kg/h ； 11. Separation efficiency: 99% ； 12. Holding time: at least two minutes ； 13. Size of gas inlet and outlet pipes: 24“ ； 14. Material: SS304.
This post was last edited by luoli519 on 11-8-2016 at 10:44. We will provide here the technical specification documents for the primary power-sail type pre-cooling and separation vessel at the top of the aforementioned regeneration distillation tower, which are part of the SD process package used in that company’s EO/EG units, for everyone’s reference and discussion:
This post was last edited by luoli519 on 11/8/2016 at 10:45. Here, the technical specification documents for the primary dynamic umbrella-type pre-cooling and separation vessel at the top of the aforementioned regeneration distillation tower, as part of the SD process package used in this enterprise’s EO/EG units, are provided for everyone’s reference and discussion:
This post was last edited by luoli519 on 2019-12-27 08:21. This type of umbrella-shaped separator is specifically used for the primary pre-cooling and separation tank at the top of a distillation tower. The image below shows a paraglider-type separator manufactured in China according to the design, by one of the few professional companies in the world that possess the capability to design and manufacture such separators using paraglider technology.
This post was last edited by luoli519 on 2016-11-8 at 17:19. Here are the drawings for a power umbrella-type separator tank used for primary pre-cooling at the top of a distillation tower, developed as part of a \"one-to-one\" precision dynamic design platform by one of the few professional companies in the world capable of designing and manufacturing such separators. These drawings are provided for everyone’s reference and learning purposes. It should be noted specifically that paraglider-type separators belong to the category of dynamic separators, and their design must be carried out using a proprietary and precise dynamic design system platform provided by specialized companies in dynamic separation technology ； Using any copy of a paraglider-type separator of a certain size in other different operating conditions will result in the separator failing to operate efficiently or even not functioning at all; the user shall bear the consequences.
For distillation tower systems, domestic universities, design firms, and project owners focus their efforts only on the internal components and packing of the towers. What is not realized is that no internal tower components or packing can effectively prevent the process steam within the tower from distilling out together with the inert gas, thereby having a significant impact on the operation of the primary pre-cooling and secondary deep-cooling stages at the top of the tower. In contrast, foreign process packages place particular emphasis on the impact of condensate carried by inert gases on the efficient operation of the condensation system, as well as on the efficient operation of downstream processes that utilize inert gases. This requires owners, design firms, research institutions, and universities to learn from these practices in order to narrow the gap in understanding of process technologies between domestic and foreign standards, as well as the resulting disparity in the technical and economic efficiency of projects.