Coupling of CFD and semiempirical methods for designing three-phase condensate separator: case study and experimental validation

This study presents an approach to determine the dimensions of three-phase separators. First, we designed different vessel configurations based on the fluid properties of an Iranian gas condensate field. We then used a comprehensive computational fluid dynamic (CFD) method for analyzing the three-phase separation phenomena. For simulation purposes, the combined volume of fluid–discrete particle method (DPM) approach was used. The discrete random walk (DRW) model was used to include the effect of arbitrary particle movement due to variations caused by turbulence. In addition, the comparison of experimental and simulated results was generated using different turbulence models, i.e., standard k–ε, standard k–ω, and Reynolds stress model. The results of numerical calculations in terms of fluid profiles, separation performance and DPM particle behavior were used to choose the optimum vessel configuration. No difference between the dimensions of the optimum vessel and the existing separator was found. Also, simulation data were compared with experimental data pertaining to a similar existing separator. A reasonable agreement between the results of numerical calculation and experimental data was observed. These results showed that the used CFD model is well capable of investigating the performance of a three-phase separator

Hemoptysis after subclavian vein puncture for pacemaker implantation: A case report

Background: Subclavian venous access for pacemaker lead insertion is a common procedure and is normally considered safe in the hands of an expert. However, subclavian venepuncture is not without complications, starting from mild subcutaneous hematoma to pneumothorax. We here present a case of hemoptysis occurring after difficult subclavian vein puncture, which subsequently improved on conservative management only. Case Summary: A 65-year-old gentleman, post aortic valve replacement had persistent high-grade AV block and was taken up for a dual chamber pacemaker implantation. Immediately following venous access, he had a bout of hemoptysis, which recovered on its own. Post procedure chest x-ray was suggestive of alveolar hemorrhage which cleared gradually in next three-four days. Discussion: Post subclavian venepuncture hemoptysis is known; but it is a rare complication, arising either because of lung parenchyma injury or arterial injury. This is mostly benign and improves on conservative management only; however rarely it may be massive and life threatening where transcatheter arterial embolization may be required

Calix[n] imidazolium as a new class of positively charged homo-calix compounds

Macrocycles based on neutral calixarenes and calixpyrroles have been extensively explored for ion binding, molecular assembly and related applications. Given that only these two types of calix compounds and their analogs are available, the introduction of new forms of widely usable calix macrocycles is an outstanding challenge. Here we report the quadruply/quintuply charged imidazole-based homo-calix compounds, calix[4/5] imidazolium. The noncovalent (C-H)(+)/pi(+) -anion interactions of the imidazolium rings with anions inside and outside the cone are the stabilizing factors for crystal packing, resulting in self-assembled arrays of cone-shaped calix-imidazolium molecules. Calix[4] imidazolium senses fluoride selectively even in aqueous solutions. Calix[5] imidazolium recognizes neutral fullerenes through pi(+) -pi interactions and makes them soluble in water, which could be useful in fullerene chemistry. Not only derivatization and ring expansion of calix[n] imidazolium, but also their utilization in ionic liquids, carbene chemistry and nanographite/graphene exfoliation could be exploited.close10