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Computational fluid dynamics simulations were performed to investigate the behavior of dilute phase pneumatic conveying of plastic pellets in a horizontal circular pipe. The pellets are 200 µm in d...

The main objectives of this work is to produce detailed velocity profile measurements over a range of operating conditions of two phase gas/liquid flow with low liquid fractions in horizontal and inclined pipes. The experiments are performed in a 15 m long stainless steel pipe section with internal diameter 56 mm at room temperature and atmospheric outlet pressure. Exxsol D60 oil (viscosity 1.30 mPa s, density 793 kg/m3), water (viscosity 0.89 mPa s, density 999 kg/m3) and air (viscosity 0.018 mPa s, density 1.22 kg/m3) are used as test fluids. The pipe inclination is changed in the range from 5° upward to 5° downward. The measurements are made at mixture velocity, 5 m/s for different inlet liquid fractions. The cross-sectional distribution of phase fractions is measured using a traversable single-beam gamma densitometer. The particle image velocimetry (PIV) is utilized in order to obtain non-invasive instantaneous velocity measurements of the flow field. Based on the instantaneous local velocities, mean velocities, root mean squared velocities and Reynolds stresses are calculated. The measured mean velocity and turbulence profiles show a strong dependency with pipe inclination. The present measurements show that PIV can be successfully used as a practical measurement technique for multiphase flow applications with potential to become even more powerful in the near future as digital camera technology progresses.

This study investigated the applicability of the multiphase particle-in-cell (MP-PIC) method for predicting pneumatic conveying characteristics. Three-dimensional computational particle fluid dynamics (CPFD) simulations were performed to assess the dilute-phase pneumatic conveying of plastic pellets in a horizontal circular pipe. The pellets were 80–500 μm in diameter and 1000 kgm− 3 in density. The air velocities ranged from 6 to 15 ms− 1, and the solids-to-air mass flow ratios (solids loading ratios) ranged from 1 to 3. The predicted pressure drops and solids and air velocity profiles were compared with experimental data from the existing literature. A parametric study was carried out to investigate the effects of model collision parameters on pneumatic conveying characteristics. Moreover, the importance of including new collision terms developed by other researchers in the MP-PIC method for the prediction of dilute phase flows was emphasized.

The use of a pneumatic conveying technique for the transportation of drill cuttings within and from offshore drill rigs is a new and challenging research field at present. In addition to experimental techniques, computational fluid dynamics (CFD) can be used for detailed understanding of the process. CFD modelling of pneumatic conveying is not very new; however, the nature of the drill cuttings introduces additional challenges for the modelling work. In the present paper, published information related to the CFD modelling of pneumatic conveying is presented in general and in detail. The information covers a wide range of pipe geometries/orientations (horizontal, vertical, different types of bends/elbows), operating conditions (air velocity, solid loading) and solid materials (particle size, particle density) being transported. The model approaches used for the predictions (Eulerian or Lagrangian, collision model, software) and the main focus/results are also presented. Next, the main challenges with regard to modelling of drill cuttings transport are addressed. The inevitable variance in cutting composition, wetness, oiliness, non-sphericity, very wide particle size distribution and degradability/instability of drill cuttings are identified as the major challenging factors.

Viscosities of liquid solutions of monoethanolamine (MEA), water (H20), and carbon dioxide (CO2) have been measured. The mass fraction of MEA was (10, 20, 30, 40, and 50)%, and CO2 loading values was between (0.1 to 0.5) mol CO2/mol MEA. The operating temperature was varied between (20 to 150)°C. The available literature data for temperature range (25 to 80)°C for mass fraction of (20, 30 and 40)% were used to compare the measurement data. The dynamic viscosity increase with the increase of CO2 loading and decrease with an increase of temperature. The measured data were compared with the data predicted from available regression equation for certain temperature range. Agreement between measured data and the correlation data was satisfactory.

Because of high environmental impacts and energy costs, many cement plants tend to substitute waste-derived fuels for fossil fuels. However, knowing the impacts of using such waste fuels is important for improving the process economy. This paper presents a three-dimensional computational fluid dynamics (CFD) modelling study conducted for a cement rotary kiln. Simulations are performed using commercial CFD software and are conducted for coal, as well as for meat and bone meal (MBM) combustion. The effects of fuel feeding position and fuel particle size on the combustion characteristics are discussed. Annulus fuel feeding gives faster devolatilization and char combustion than central-tube fuel feeding, and the effect is significant for larger particles. The devolatilization is much faster for small particles. For a given fuel, the larger the mass-weighted mean particle diameter, the lower the char burnout. The negative effect of a large mass-weighted mean particle diameter on the char burnout is more significant for fuels having high fixed carbon content. However, the impact on the gas temperature due to poor char burnout depends on the fixed carbon content of the fuel.

In the present study, vertically upward dilute phase pneumatic conveying flow was predicted using Euler - Granular method. Three dimensional computational fluid dynamics simulations were carried out for an 8 m long and 30.5 mm diameter circular pipe. The dens ity of conveyed materials was 1020 kg/m 3 . Simulations f or different particle diameters; 200 μm and 500 μm were performed. The air velocities ranged from 9 to 17 m/s and solid to air mass flow ratios ranged from 0.0 to 3.8. Pressure drop, air and particle velocity profiles and solid distribution profiles were studied and some of the results were compared with experimental data from existing literature. Predicted pressure drop and air velocity profiles are in good agreement with experimental results.

The offshore drilling operations generate huge volume of drill cuttings. Rig site transfer of cuttings can be a challenge both if pneumatic conveyors or screw conveyors are used. Especially, wet powder is a challenge since the particles become too sticky for easy handling or too dry for acting like a slurry. This paper presents the preliminary results of a scientific investigation aimed to study transport properties and storage criterion of dry and partially-moist solids drill cuttings. Model materials have been tested in pilot scale pneumatic conveying rigs and CFD simulation on particle conveying has been performed in parallel. The pilot scale tests have been conducted for the sand particles in the size range of 0.1 – 3 mm diameter under the air flow rate of 13-23 ms-1 The simulations were carried out using multiphase particle-in-cell method (MP-PIC) for dry particles that are having particle size distribution in the range of 0.3-3 mm diameter. Pressure drop in a horizontal section is studied and it was observed that at a minimum pressure drop and a minimum specific power requirement is reached when decreasing the superficial air velocity. This region can be considered as the economical region for operation. For the considerd particle size this region was obtained at the air velocity of 16-19 ms-1 for a horizontal pipe section with 81.2 mm diameter. In the simulations, the predicted pressure drops in 15-22 ms-1 velocity range are in good agreement with experimental results. The combination of pilot scale pneumatic conveying tests and simulations of dry drill cuttings provide a platform to evaluate and predict pneumatic conveying parameters for partially-moist drill cuttings.

The calcium carbonate decomposition into calcium oxide and carbon dioxide is a key process step in a cement kiln. The reaction requires thermal energy input, and pulverized coal is the fuel typically used for this purpose in the cement industry. Coal can in many cases be replaced by different types of alternative fuels, but this may impact process conditions, emissions or product quality. In this study, CFD simulations were carried out to investigate the possibility to replace 50 % of the coal by refuse derived fuel (RDF). The spatial distribution of gas and particle temperatures and concentrations were calculated, and the simulations indicated that replacement of coal by RDF resulted in a reduction of fuel burnout, lower gas temperatures and a lower degree of calcination.

 Abstract—This paper presents a three-dimensional computational fluid dynamics (CFD) modeling study carried out for a rotary cement kiln withal multi-channel burner with swirl and high momentum air components. The simulations are performed using the commercial CFD software ANSYS FLUENT, version 13.0, and are carried out for coal as well as for meat and bone meal (MBM) combustion using the eddy-dissipation model for combustion. Steady-state solutions are obtained using the Lagrangian approach for the particle phase and the Eurasian approach for the continuous phase. The turbulence is modeled by the RNG k-e model, and gas-phase radiation is modeled by the P1 radiation model. The effect of MBM fuel properties on combustion characteristics such as temperature, fuel devolatilization, volatiles and char burning, in comparison with coal, are presented and discussed. It was found that MBM combustion products temperatureis300K lower than that of coal, and the char burnout of MBM is 83%. This poor burnout is mainly due to bigger MBM particles.

Increased use of alternative fuels in cement kilns is a trend in the world. However, replacing fossil fuels like coal with different alternative fuels will give various impacts on the overall kiln process due to the inherent fuel characteristics. Hence, it is important to know to what extent the fossil fuels can be replaced by different alternative fuels without severely changing process conditions, product quality or emissions. In the present study, a mathematical model based on a mass and energy balance for the combustion of different alternative fuels in a cement rotary kiln was developed. First, the impact of different fuel characteristics on kiln gas temperature, kiln gas flow rate and air requirement were observed by using coal (reference case), meat and bone meal (MBM), two different wood types, refuse derived fuel (RDF) and a mixture of saw dust and solid hazardous waste as the primary fuel. It was found that the key process parameters depend largely on the chemical characteristics of the fuel. It appears that MBM shows quite different results from other alternative fuels investigated. Next, simulation of combustion of a mixture of coal and MBM in the rotary kiln burner was carried out in three steps in order to find the reduction in production capacity compared to the reference case. Around 9% of reduction in clinker production rate could be observed when replacing 59% of the coal energy input. Results from a full-scale test using the same mixture of coal and MBM verified the simulation results.

An absorption and desorption rig has been in operation at Telemark University College since 2010. The purpose of the rig is to perform measurements of CO2 removal efficiency and heat consumption at different process conditions like temperatures, flows and CO2 concentrations in the gas and the liquid. 30 wt-% monoethanolamine (MEA) in water has been the most used solvent. In earlier work, the heat consumption has been indirectly measured by the electricity consumption for steam production. In this work new results from 2012 and 2013 are presented where the steam consumption has been measured directly by a vortex flow meter.

For an installed silicon-based solar cell panel, about 40% of the energy needed for fabrication is consumed for production of the silicon feedstock. Reducing the energy consumption in this step is therefore crucial in order to minimize the energy payback time and cost of the technology. The most promising alternative to the conventional methods is to use fluidized bed reactors. In this article, we report the results from a novel reactor layout with a selectively cooled distribution arrangement. Important aspects of fludized bed monitoring and operation are described. Two different operation regimes are stated yielding hence porous and dense growth. Further, the method of encapsulating fines by means of more dense depositions is verified, and the nature of the scavenged material is characterized. Also, two different types of fines formation are identified and accounted for.

Modelling work related to carbon dioxide (CO 2 ) capture technologies is of great importance with respect to the design, control, and optimization of the capture process. Development of dynamic models as such is important since there is much information embedded with the dynamics of a plant which cannot be studied with steady state models. A model for the absorption column of a post-combustion CO 2 capture plant is developed following the rate based approach to represent heat and mass transfer. The Kent–Eisenberg model is used to compute the transfer and generation rates of the species. Sensitivity of the model for different physiochemical property correlations is analyzed. The predictions of the dynamic model for the capture plant start-up scenario and operation of the absorption column under varying operating conditions in the up-stream power plant and the down-stream stripping column are presented. Predictions of the transient behaviour of the developed absorber model appear realistic and comply with standard steady state models.

A dynamic model for simulating an amine based CO2 absorption plant is developed. The model represents all of the major equipment included in a CO2 capture plant with alkanolamines as the solvent system. A non-equilibrium rate is used as the base for representing the heat and mass transfer in the absorption and desorption columns. Steady state results from simulation of a pilot plant case was compared with the experimental data from the literature as a validation of the model. The steady state results used for validation of the model show good agreement with the literature data. Dynamic simulations were performed to analyze the capability of the model to predict the effect on the plant operation caused by the disturbances from the up-stream power plant and the operating conditions of the plant itself.

Densities and surface tensions of carbon dioxide (CO2) loaded (partially carbonated), aqueous monoethanolamine (MEA) solutions with amine mass ratios from (0.2 to 0.7) are measured within a temperature range from (303.15 to 333.15) K. The series of aqueous MEA solutions covers a range of CO2 loading from (0 to 0.5). All the density data points are compared with the predictions of the model from Weiland et al., and data regression is performed to fit the parameters of the model. Predictions from the fitted model are compared with the data reported in this work. The model of Connors and Wright is selected to represent the surface tension data of the H2O–MEA–CO2 tertiary system. Data reported in this work are used to fit the parameters of the Connors and Wright model, and the model predictions are compared with the same set of data.

Fluidization experiments were performed using several particle size distributions of spherical glass particles, ranging from Geldart B to D. An Electrical Capacitance Tomography (ECT) tomograph was utilized in the present study and its usefulness as a diagnostic tool is illustrated. During the experiments a 10.4 cm diameter column was utilized and the column was operated at atmospheric pressure and room temperature (cold fluidized bed). Statistical analyses were performed on the average solid fraction data obtained using the ECT tomograph. Using the time domain skewness and kurtosis the time series could be characterised and the quality of fluidization is determined at different superficial gas velocities (Azizpour, H., Sotudeh-Gharebagh, R., Zarghami, R., Abbasi, M., Mostoufi, N., Mahjoob, M., 2011. Characterization of gas–solid fluidized bed hydrodynamics by vibration signal analysis. International Journal of Multiphase Flow, 37, 788–793). Statistical analysis is also used to characterise the influence of small particles on the bed hydrodynamics.

Densities and surface tensions of carbon dioxide (CO2) loaded (partially carbonated), aqueous monoethanolamine (MEA) solutions with amine mass ratio of 0.8 are measured within a temperature range from (313.15 to 343.15) K. The series of aqueous MEA solutions cover a range of CO2 loading from (0 to 0.5). All of the density data points are compared with the predictions of the model from Weiland et al., and data regression is performed to fit the parameters of the model. Predictions from the fitted model are compared with the data reported in this work. The model of Connors and Wright is selected to expand for the H2O–MEA–CO2 tertiary system. Surface tension data from this work are used to fit the parameters of the Connors and Wright model, and the model predictions are compared with the same set of data.

Carbon capture and storage (CCS) is a potential means of mitigating the contribution of the green house gas emissions from the fossil fuel usage to the global warming. Post combustion CO2 capture via amine absorption is one of the most matured techniques to comprehend the goals of CCS. A Dynamic model of an amine based post combustion capture plant including the absorption and stripping towers is developed in order to contribute in the journey from the lab scale towards the industrial scale capture plants. The dynamic model is validated against the literature data. The capability of the model to predict the dynamics of a post combustion CO2 capture unit is analyzed via a possible scenario of a real plant.

In this paper, both the main effects and interaction effects of parameters on CO 2 removal efficiency were investigated. Flue gas stream data from a 500MW coal power plant has been used for the model development. The complete removal process is implemented in Aspen Plus with selected operating conditions and parameters using Monoethanolamine as solvent. The base case model is developed in Aspen Plus with specific parameter values to achieve 85% removal efficiency. The CO 2 removal efficiency variation with different parameters; such as number of stages, inlet solvent flow rate, lean loading, temperature of the flue gas and solvent stream, absorber packing height and diameter and absorber pressure are considered as the most important parameters for sensitivity analyses. The data collected from simulations were analysed using Principal Component Analysis, Principal Component Regression and Partial Least Square-regression. The correlation between variables were studied, which indicate that inlet solvent flow rate, absorber packing height and diameter, absorber pressure and temperature of the solvent stream are positively correlated with CO 2 removal efficiency whereas the lean loading and temperature of flue gas are negatively correlated with efficiency.

An absorption and desorption rig has been built at Telemark University College. The absorption column has a structured packing height of 1500 mm, a total height of 2500 mm and an inner diameter of 100 mm. The desorption column has a random packing height of 1000 mm and a total height (including a reboiler and a condenser) of 3000 mm. The rig also contains a rich/lean heat exchanger, a solvent cooler and two pumps. The purpose of the rig is to perform measurements of CO 2 removal efficiency and energy consumption at different temperatures, flows and CO 2 concentrations. Different solvents like carbonate solutions and amine mixtures can be studied. The CO 2 absorption rig has been used successfully to measure the absorption efficiency as a function of different parameters at stable conditions. The measurements can be used to validate process calculations and to find optimum process conditions.

A new experimental set-up was established to measure liquid phase mass transfer coefficient of CO 2 absorption by single water droplet. The experiments were performed at 303.65 K and 323.15 K, with a droplet falling height of 0. 41 m and 0.59 m. The droplet formation time varies from 0.352 s to 2.315 s. The droplet diameter changes little and is around 2.5 mm. The effects of temperature, droplet falling height and droplet formation time on CO 2 absorption by individual water droplet are discussed.

For an installed silicon based solar cell panel, about 40% of the energy costs involved in the production of the panels can be attributed to the production of the silicon feedstock itself (poly production and crystal growth). Hence reducing the energy consumption in these steps is crucial in order to minimize the energy payback time of installed capacity. For the first step, viz., the poly production, the most promising cost reduction alternative is the fluidized bed reactors (FBR) using silane as a precursor rather than trichlorosilane (TCS) since for TCS the reverse reactions makes the theoretical trichlorosilane conversion substantially lower. Use of silane has, however, many challenges and scaleup to larger capacity can be achieved if associated risks are properly dealt with. This paper outlines some of these challenges and provides a detailed survey of the current status on the growth mechanism and kinetics of silane pyrolysis. The paper also provides a summary of modeling of fluidized bed reactors (FBR) in some depth and give some empirical insight to key aspects in FBR scaleup design.

Densities of carbon dioxide loaded (partially carbonated), aqueous diethanolamine (DEA) solutions and aqueous methyldiethanolamine (MDEA) solutions are measured within a temperature range from (293.15 to 423.15) K. The series of DEA and MDEA aqueous solutions cover a range of amine mass ratios from (0.5 to 0.8) and a range of CO2 loading from (0 to 0.5) mol CO2·mol amine–1. All of the data points are compared with the predictions of the model from Weiland et al., and data regression is performed to fit selected parameters of the model. Predictions from the model fitted in this work are compared with the data measured in this work. The capability of the fitted model to predict the densities of the partially carbonated aqueous DEA and MDEA solutions with amine mass ratios different from what is used in this work is analyzed.

The Eulerian–Eulerian approach is used to predict wall to bed heat transfer coefficient in a gas–solid fluidized bed with a jet by a heated wall. The constant viscosity model (CVM) and kinetic theory of granular flows (KTGF) are used to describe the solid phase rheology. A solid phase molecular thermal conductivity model specifically developed for the near wall region is used in the present work since wall to bed heat transfer occurs through the particle layer in contact with the wall. A comparison of the predicted and measured heat transfer coefficient is presented for different jet velocities, particle sizes and particle types and good agreement is observed between the predicted and measured values. It is observed that the predicted heat transfer coefficient is not affected significantly by the drag model or solid phase rheology model (CVM or KTGF) provided all other model parameters and operating conditions are same. Additionally for KTGF, over-prediction of heat transfer coefficient is observed in the case where solid phase thermal conductivity is expressed in terms of granular temperature rather than molecular conduction. Inclusion of particle rotation in the KTGF model reduces this over-prediction by around 17%.

Densities in liquid solutions of water + diethanolamine (DEA) and water + N-methyldiethanolamine (MDEA) have been measured at temperatures from (298.15 to 423.15) K. The mass fraction of amine ranged from 0.3 to 1.0. Excess molar volumes of the binary system were derived and correlated by a fourth order Redlich–Kister equation and a second polynomial function with respect to the temperature. Densities in liquid solutions of water + DEA + CO2 and water + MDEA + CO2 have been measured at temperatures from (298.15 to 423.15) K. The mass fraction of amine in water was 0.3 and 0.4. The CO2 loading ranged from 0.1 to 0.5. Molar volumes of the ternary system were correlated by the equation from Weiland et al. at each temperature. The parameters were in turn fitted by a polynomial function of the temperature.

Densities in liquid solutions of monoethanolamine (MEA) and water have been measured at temperatures from (298.15 to 423.15) K. The mass fraction of MEA ranged from 0.3 to 1.0. Excess volumes were correlated by a Redlich–Kister equation. The model uses a third-order Redlich–Kister equation and a linear relationship with the temperature. Densities of CO2 loaded aqueous MEA solutions were measured at temperatures from (298.15 to 413.15) K. The mass fraction of MEA was 0.3, 0.4, 0.5, and 0.6. Molar volumes of CO2 loaded aqueous MEA solutions were correlated by the equations from the literature. Polynomial equations are in turn used to correlate the parameters with the temperature. Surface tensions of aqueous MEA solutions were measured at temperatures from (303.15 to 333.15) K. The mass fraction of MEA ranged from 0 to 1.0. The experimental surface tension data were correlated with temperature and mole fraction, respectively.

Meat and Bone Meal (MBM) is a CO2 neutral fuel, and hence is a good candidate for substituing fossil fuels like pulverized coal in rotary kiln burners used in cement kiln systems. MBM is used in several cement plants, but the optimum substitution rate has apparently not yet been fully investigated. The present study aims to find the maximum possible replacement of coal by MBM, without negatively affecting the product quality, emissions and overall operation of the process. A full-scale experiment was carried out in the rotary kiln burner of a cement plant by varying the MBM substitution rate from 0 to 7 t/hr. Clinker quality, emissions and other relevant operational data from the experiment were analysed. Additionally, coal and MBM were compared by laboratory experiments. The results revealed that MBM could safely replace more than 40% of the coal energy without giving negative effects. The limiting factor is the free lime content of the clinker. Possible explanations to the free lime increase are given. If 40% of the coal in the rotary kiln burner was replaced by MBM on a long-term basis, the total annual CO2 emissions of the plant could be reduced by 10%.

The effect of the fluidization air flow rate and the transport air velocity on the solids mass flow rate and the pressure drop along the transport pipe was investigated in a vertical air-lift. The use of two different materials, glass (150 μm) and zirconium oxide (260 μm) particles (Geldart's B class), enabled to estimate the effect of particle properties on the air-lift performance. Different levels of the solids mass flow rate were obtained by varying the fluidization air flow rate while keeping the transport air velocity constant. The solids loading ratio varied between 2 and 16 for both types of particles. The pressure drop was non-linearly related to the solids mass flow rate at most of the transport air velocities tested. State diagrams presenting the relationship between the transport air velocity, the solids mass flow rate, and the pipeline pressure drop were constructed to characterize the flow pattern and to compare the behavior of the glass and zirconium oxide particles. Owing to the larger size and higher density, the zirconium oxide particles displayed higher pressure drop values than the glass beads and the minimum pressure drop shifted towards higher transport air velocities. The velocity at the transition between dilute and dense phase conveying was approximately in the range of 7 to 10 m/s for glass beads and 10 to 12 m/s for zirconium oxide, at the solids mass flow rates tested. The flow patterns could be also effectively characterized from the analysis of the pressure drop fluctuations at different transport air velocities.

NOTICE: this is the author's version of a work that was accepted for publication in Energy Procedia. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in ENERGY PROCEDIA, VOL 4, (2011) DOI http://dx.doi.org/10.1016/j.egypro.2011.02.056 Post combustion CO2 capture via absorption into aqueous alkanolamine systems is considered to be the most mature and potential technique for CO2 removal from the power plants' exhaust gases. Modeling and simulation of such plants have achieved an interesting place in research, and several steady state models already exist. Though steady state models are capable of giving an understanding of the process, dynamic models are most useful for controlling and optimizing the plants. A dynamic model for the absorption column in a CO2 removal plant is been developed. Usability of simple thermodynamics for modeling is checked with the development of this model, instead of using complex thermodynamic models which are very popular in recent research. It is concluded that the steady state simulation results show a good agreement with the trend of the available pilot plant data. Dynamic predictions of the model indicate that the model is capable of handling an excitation of the inputs and reaches steady states. Yet, the whole CO2 absorption plant has to be included into the dynamic model before it is ready to be used for control or optimization applications.

For an installed silicon based solar cell panel, about 40% of the energy consumed producing the cell was used during production of the silicon feedstock. Reducing the energy consumption in this step is therefore crucial in order to minimize the energy payback time of installed capacity. The most promising alternative to the conventional methods is fluidized bed reactors (FBR). The development of FBR for the production of polysilicon is here reviewed. Through the last half century several research groups and companies have contributed to the development of such reactors to a point where the method is competitive on the terms given in today's marked. Most work within the field of research has been done by the industry and this has resulted in few articles and a substantial amount of patents on the topic. This article aims to summarize the development and to paint the complete picture on what concepts have been investigated, what challenges arose and where the development stands today.

The simultaneous flow of oil and water in pipelines is a common occurrence in the chemical and process industry. An experimental investigation of oil–water flow in horizontal and slightly inclined pipes is presented in this paper. The experiments are performed in a 15 m long stainless steel pipe section with internal diameter 56 mm at room temperature and atmospheric outlet pressure. Exxsol D60 oil (density 790 kg/m 3 and viscosity 1.64 mPa s) and water (density 996 kg/m 3 and viscosity 1.00 mPa s) are used as test fluids. The pipe inclination is changed in the range from 5° upward to 5° downward. The measurements are made for two different mixture velocities, 0.50 and 1.00 m/s at water cut 0.50. The cross-sectional distribution of phase fractions in oil–water flow is measured using a traversable single-beam gamma densitometer. The different flow regimes are determined based on visual observations. The particle image velocimetry (PIV) is utilized in order to obtain non-invasive instantaneous velocity measurements of the flow field. Based on the instantaneous local velocities, mean velocities, root mean squared velocities and Reynolds stresses are calculated. Stratified flow with mixing at the interface is observed at mixture velocity 0.50 m/s. Interfacial waves are observed in upwardly and downwardly inclined flows. At mixture velocity 1.00 m/s, interfacial mixing is increased and dual continuous flows are observed. The degree of mixing largely depends on the pipe inclination. In general, higher water hold-up values are observed for upwardly inclined flows compared to the horizontal and downwardly inclined flows. The slip between the phases increases as the pipe inclination increases. The maximum mean axial velocity is detected in the more viscous oil phase at equal volumetric flow rates of oil and water. In addition, measured mean velocity and turbulence profiles show a strong dependency with pipe inclination. The largest root mean squared velocities and absolute values of the Reynolds stresses are observed close to the pipe wall due to higher mean axial velocity gradients. A damping effect of Reynolds stress is observed around the oil–water interface due to stable density stratification. The presence of interfacial waves enhances turbulence fluctuations in inclined oil–water flows.

Gamma densitometry is a frequently used non-intrusive method for measuring component volume fractions in multiphase flow systems. The application of a single-beam gamma densitometer to investigate oil–water flow in horizontal and slightly inclined pipes is presented. The experiments are performed in a 15 m long, 56 mm diameter, inclinable stainless steel pipe using Exxsol D60 oil (viscosity 1.64 mPa s, density 790 kg/m3) and water (viscosity 1.0 mPa s, density 996 kg/m3) as test fluids. The test pipe inclination is changed in the range from 5° upward to 5° downward. Experimental measurements are reported at three different mixture velocities, 0.25, 0.50 and 1.00 m/s, and the inlet water cut is varied from 0 to 1. The gamma densitometer is composed of radioactive isotope of Am-241 with the emission energy of 59.5 keV, scintillation detector [NaI(Tl)] and signal processing system. The time averaged cross-sectional distributions of oil and water phases are measured by traversing the gamma densitometer along the vertical pipe diameter. Based on water volume fraction measurements, water hold-up and slip ratio are estimated. The total pressure drop over the test section is measured and frictional pressure drop is estimated based on water hold-up measurements. The measurement uncertainties associated with gamma densitometry are also discussed. The measured water hold-up and slip ratio profiles are strongly dependent on pipe inclination. In general, higher water hold-up values are observed in upwardly inclined pipes compared to the horizontal and downwardly inclined pipes. At low mixture velocities, the slip ratio decreases as the water cut increases. The decrease is more significant as the degree of inclination increases. The frictional pressure drop for upward flow is slightly higher than the horizontal flow. In general, there is a marginal difference in frictional pressure drop values for horizontal and downwardly inclined flows.

In this work, a comparison of Particle Image Velocimetry (PIV) and Laser Doppler Anemometry (LDA) measurement methods was made applied to oil–water two-phase flow in a horizontal pipe. The experiments were conducted in a 15 m long, 56 mm diameter stainless steel pipe using Exxsol D60 oil (density 790 kg/m 3 and viscosity 1.64 mPa s) and water (density 996 kg/m 3 and viscosity 1.0 mPa s) as test fluids. The experiments were performed at different mixture velocities and water cuts. Mixture velocity and water cut vary up to 1.06 m/s and 0.75, respectively. The instantaneous local velocities were measured using PIV and LDA, and based on the instantaneous local velocities mean velocities and turbulence profiles are estimated. The measurements are performed in the vertical plane through the pipe center. A double-pulsed Nd:yttrium aluminium garnet (YAG) laser and a high-speed camera with 1260×1024 px resolution (1.3 Mpx) were used for the PIV measurements. The LDA set-up is a two-colour backscatter system with 3 W Argon-Ion Laser. The time averaged cross-sectional distributions of oil and water phases were measured with a traversable gamma densitometer. The measured mean axial velocity and turbulence profiles using PIV were observed to compare favourably well with LDA measurements. Nevertheless, the PIV measurements are more sensitive for optical disturbances in the dispersed region close to the oil–water interface. Hence, this region cannot be confidently analyzed using PIV, whereas LDA offers full-field measurements even at higher mixture velocities.

Although some literature can be found on the behavior of blow tanks, very few studies could be found on the pressure loss at the entry section to a pipeline (henceforth called entry pressure loss) from a top discharge blow tank in a pneumatic conveying system, even though its magnitude can be significant as compared to the total system pressure drop. This article presents the results of an experimental study carried out to assess this entry pressure loss. The results indicate that it is possible to scale up the entry pressure loss based on laboratory-scale tests with a reasonable degree of accuracy.

Dilute vertical pneumatic transport has been studied by using the experimental techniques LDA and PIV. LDA and PIV are two different techniques, but they are both common methods used to gain a better understanding of gas/particle multiphase flows. A comparison between the two methods has been performed. The main focus of this study was an experimental LDA investigation of ZrO2 particles and glass beads. The particles have approximately the same particle size distribution but different densities. The superficial gas velocity and the particle loading have also been varied in the experiments. The effects of superficial gas velocity, particle loading, and particle density on the particle mean velocities, particle u-rms, particle v-rms, and particle cross-moment were investigated. From the experimental investigation it was found that the axial particle velocities showed a dependence on the particle volume fraction for the ZrO2 particles. It was also observed that the axial fluctuations decreased for both glass...