Review of arsenic behavior during coal combustion: Volatilization, transformation, emission and removal technologies

A new hydrate deposition prediction model for gas-dominated systems with free water

Prediction of hydrate deposition in pipelines to improve gas transportation efficiency and safety

Supersonic separation technology is a new approach to condense and separate water, heavy hydrocarbons and other impurities from natural gas. This paper reviews the research advances in condensation characteristics of the Laval nozzle and separation mechanism of the supersonic separator in detail from the perspectives of theoretical analysis, experiments and numerical simulation, and summarizes the new application of this technology including natural gas liquefaction and removal of the acid gases. This review points out that while several aspects of this technology have been well studied, there still exist several issues in the practice. The further research topics are clarified to promote future applications such as the model modification of gas spontaneous nucleation rate to improve the prediction accuracy, and the combination the molecular dynamics technology with interface mechanics theory to study the collision and coalescence of the droplets and the interaction between gas and droplets under supersonic conditions.

Supersonic separation technology for natural gas processing: A review

A new approach to investigate hydrate deposition in gas-dominated flowlines

The computational fluid dynamics technique was used to study the behavior of high-pressure natural gas in supersonic nozzles. Although many applications of gas flow produce insignificant errors when the gas is assumed ideal, our results indicate significant variation of gas properties. This article illustrates natural gas behavior when it is considered to be real and how erroneous the properties may become when the gas is assumed to be ideal. The article also presents the influences of properties related to the flow of natural gas through supersonic nozzles. Using a quite accurate equation of state model, real gas effects are studied and compared with the perfect gas case. The results show a significant variation in gas properties estimation. Location of shockwave is also analyzed. The comparison of results for two gases (methane and nitrogen) indicated that shockwave position can significantly change when the gas is considered as real rather than perfect.

Computational Fluid Dynamics Study for Flow of Natural Gas through High-pressure Supersonic Nozzles: Part 1. Real Gas Effects and Shockwave

The computational fluid dynamics technique is used to study the behavior of high-pressure natural gas when it flows through nozzles with supersonic velocities. Effect of nozzle geometry is discussed by inserting a constant area channel between the convergent and divergent parts of the system. Various conduit lengths are analyzed to show how the minimum temperature could be influenced by the geometry of the nozzle. The results also show that changing channel length can affect the position of shockwave. The results for the effect of vorticity on the performance of the nozzles show that, although losses in pressure increase due to inlet swirl flow, vorticity increases very sharply in the vicinity of the shock. It could be concluded that the region just before the shock spot is the main region where fine particles can be separated because of the large vorticity strength. Shock with reasonable strength may be favored in practical applications where fine particles separation is desired.

Computational Fluid Dynamics Study for Flow of Natural Gas through High-pressure Supersonic Nozzles: Part 2. Nozzle Geometry and Vorticity

A CFD-Based Model to Locate Flow-Restriction Induced Hydrate Deposition in Pipelines

The aim of the study is to experimentally investigate and compare the influence of two different nanofluids (Cu/water and Al2O3/water) on the performance of a double pipe heat exchanger at different volume concentrations and flow rates. Effect of varying hot-side inlet temperature is also tested for the selected concentrations. The nanofluid, pumped on the shell-side of the heat exchanger, has a Reynolds number ranging from 7000 to 15,000 while, for each Reynolds number, the concentration of the nanoparticles ranges from 0.26% - 0.83% on volume basis. Results indicated that presence of nanoparticles within the base fluid can offer a great potential for energy transfer. Observation of experimental outcomes shows notable enhancement in the Nusselt number when increasing the mass-flow of the nanofluid. The enhancement registered for the above mentioned range of Re and concentration are up to 13% for Al2O3 and 23% for Cu. Experimental results show a considerable improvement in the effectiveness (up to 7% for aluminum oxide and 10% for copper). Also, the performance enhances with the augmentation of the hot-side inlet temperature. Heat leak from the shell-side (cold fluid) to atmosphere is observed to be enlarged when nanoparticle is employed and is proportionally related to the concentration. It is also monitored that the heat leak within aluminum oxide nanofluid is greater than the copper nanofluid.

Esam I. Jassim

Papers

A new approach to investigate hydrate deposition in gas-dominated flowlines

Computational Fluid Dynamics Study for Flow of Natural Gas through High-pressure Supersonic Nozzles: Part 1. Real Gas Effects and Shockwave

Computational Fluid Dynamics Study for Flow of Natural Gas through High-pressure Supersonic Nozzles: Part 2. Nozzle Geometry and Vorticity

A CFD-Based Model to Locate Flow-Restriction Induced Hydrate Deposition in Pipelines

Experimental assessment of Al2O3 and Cu nanofluids on the performance and heat leak of double pipe heat exchanger