Problems with gas-liquid separation and oil separation in three-phase separators

This post was last edited by luoli519 on 2016-4-22 at 16:30. Since the original poster has already managed to solve such a challenging problem as the gas-liquid separation and sedimentation velocity in three-phase separators, it’s unlikely that calculating the axial flow velocity of fluids will pose a difficulty for them either I’ll ask a question first, and then guide you on how to calculate the axial flow velocities of gas-liquid and liquid-liquid phases in a three-phase separator. Question: When calculating the gas-liquid settling velocity, do you determine what type of flow regime the gas flow has? What are the airflow contraction effect and contraction angle? After determining the flow regime type, do you choose the Newtonian model formula, the Stokes model formula, or the transition regime model formula? If the airflow regime is selected incorrectly or the formulas of the calculation model are chosen wrongly, all your work will be in vain. Therefore, please be sure to verify your gas-liquid separation and sedimentation results again. Tips for calculating the axial flow velocity in a three-phase separator: 1. First, determine the actual volumetric flow velocity of each phase under the operating conditions. The compression factor must be taken into account for gases. 2. Determine the radial flow cross-sections of each phase within the target separation area, and accurately calculate the radial cross-sectional areas of each phase. 3. A high-efficiency distribution system must be installed at the inlet of the three-phase separator to ensure that the difference between the average axial velocity calculated and the velocity of the flow elements in the radial cross-section is minimal. You can carry out detailed and complex manual calculations, checking each step carefully ； You can also accomplish this using a specially designed three-phase separator platform. 4. Compare the accurate axial average flow velocity values for each phase that you have obtained, especially those corresponding to the NLL and NIL values for liquid-liquid separation, with the upper limits specified in the design standards. If these values exceed the specified limits, adjust the size and structure of the three-phase separator and recalculate the sedimentation velocities for gas-liquid and liquid-liquid separation as well as the axial flow velocities, until the requirements of the standards are met. Therefore, it is very likely that the results of the gas-liquid separation and sedimentation calculations you conducted earlier were wasted effort on multiple occasions. Since conventional three-phase separators are designed in this way, designing a new type of composite weir-chamber three-phase separator is even more challenging, requiring professionalism, care, and patience. For information on conventional three-phase separators and the new composite weir-chamber type three-phase separators, please visit http://bbs.hcbbs.com/thread-1354813-1-1.html directly on this HCH Chemicals forum. For technical design solutions, you can contact professional separation technology companies directly.

The horizontal velocity I calculated is different from the value obtained by that analysis software; in fact, it’s much lower. So I’m wondering if I didn’t take everything into account. Thank you for your reply. I still haven’t fully understood it – perhaps the formula I used for settlement is incorrect~

By the way, can Ansys be used for analysis to determine the settlement rate, horizontal velocity, and cofferdam height?~

It’s very likely. I hope the issue will be carefully examined.

Ansys is not omnipotent. As a most conventional simulation software, it is difficult to conduct targeted analysis for devices with specific structures. Otherwise, it would be unlikely for professional separation technology companies to emerge on the international stage if Ansys could handle such tasks.