Gas Flow Pressure Drop Research Articles

Theoretical and Experimental Investigation of Liquid and Gas Flow Pressure Drop through Different Sections of A Partially Closed Piping system

Multiphase flow is found in various places in nature and practice. However, multiphase flow is prevalent in the petroleum production industry. This phenomenon gives rise to a significant issue of pressure loss within piping systems, resulting in a loss in production. Multiphase flow has been studied for decades; however, with the increase in unconventional engineering methods, there is now a greater need for its study. This study investigates phenomena related to multiphase flow, such as flow regimes and pressure loss produced by friction, pipe orientation, and various fluid phase properties. An experimental system was designed, and different fluid phases were used to represent varying situations in piping systems. The system included sections of horizontal, inclined, and vertical pipe orientations experienced during hydrocarbon migration from the reservoir to the surface. To replicate industry multiphase flow in the experimental system, we used water to represent the oil and compressed air to represent gas. The pressure differences throughout the system were calculated using the Beggs and Brill Correlation, the Lockhart-Martinelli Parameter, and the Chisholm Equation. Experimental pressure differences and the effect of the choke valve positions were also recorded for the different sections of the system while observing the flow regimes produced by multiphase fluid interaction. Through the research methods, we found that most pressure losses occurred in the elbows, and most frictional pressure loss occurred in the vertical 3ft pipe, while the 45° and 90° downhill pipes experienced increased pressure.

Effect of hydrogen-enriched natural gas on flue gas waste heat recovery potential and condensing heat exchanger performance

Hydrogen-enriched natural gas (HENG) is one of the significant ways to store, transport, and utilize hydrogen energy. This paper presents the characteristics of HENG and flue gas, energy saving, carbon reduction, and condensate recovery potential of flue gas waste heat. Based on the theoretical and experimental study of the existing flue gas condensing heat exchanger (FGCHE) added at the rail of gas-fired boiler, the performance of the FGCHE under different hydrogen blending ratios is studied. The results show that augmenting the hydrogen blending ratio decreases the volume heating value of HENG, and CO2 content of flue gas. Meanwhile, the mass heating value of the HENG, the water vapor content, and dew point temperature of flue gas increase as the hydrogen blending ratio increases. The flue gas waste heat recovery utilization ratio and energy-saving efficiency of the FGCHE can be promoted. Moreover, the heat transfer capacity of the FGCHE using HENG is enhanced, while the flue gas flow pressure drop is reduced. Compared with the FGCHE used in pure natural gas systems, the all-hydrogen system increases the flue gas waste heat recovery amount by 62.4–120.4 %, reduces the flue gas flow pressure drop by 33.9 %, and reduces the carbon emission by 100 %.

An Experimental Study of Gas Flow Regime and Pressure Drop in a Random Packed Bed with Sinter Particles

The gas flow regime and pressure drop in a gas–solid packed bed with irregularly shaped sinter particles were experimentally investigated. Using a self-made experimental facility for data measurement, the gas flow pressure drop in a sinter bed layer was determined for various experimental conditions. According to the changes in the modified coefficients, α and β, for different flow regimes, the flow transitions from one regime to another in packed beds with different particle diameters were described. Furthermore, the pressure drop correlations for different flow regimes were determined, and the reliabilities of the obtained correlations were contrastively analyzed. The results show that, when the particle diameter is constant, the modified pressure drop per unit height, ΔP/Hu, increases linearly with the increasing gas superficial velocity. When the gas superficial velocity is larger than 1.15 m/s under atmospheric conditions, the gas flow regime in the sinter bed layer is the turbulent flow. Compared with the experimental correlation of the whole flow, the pressure drop correlations obtained by the piecewise fitting method provided a better prediction of the experimental values, and the average deviations of the obtained correlations for the Forchheimer flow and the turbulent flow were 5.31% and 4.07%, respectively.

Comparative study of dry pressure drop and flow behaviour of gas flow through sieve plate packing

AbstractSieve plate packing is a newly developed packing that has been used in several industries due to its simple structure and operating flexibility, and no liquid flooding. In this work, first, systematic experiments were conducted to measure the pressure drop of gas flow through six sieve plate packings. The results indicated that the geometric characteristics of the packing have complicated effects on the pressure drops. Based on this, CFD simulations on the gas flow field were conducted using the realizable k‐ε model, and flow behaviours such as the pressure drop, pressure nephogram, and velocity distributions within different packings were obtained. The simulation results clearly showed interesting flow patterns, including the contraction and expansion of the gas stream through the sieve hole, the flow separation on the sharp edge of the hole, and the vortexes formed when gas impacts the downstream plate. By comparing the flow patterns and the pressure drop under different packings operating at different conditions, the effects of the geometric characteristics of the packing on the pressure drop could be clearly distinguished from the flow behaviours, so that the variations in pressure drop with various packing structures were clearly indicated. Finally, based on the experimental data and the simulated results, correlations for the prediction of the pressure drops were proposed. This work will provide a useful basis for understanding the flow behaviour of gas and liquid two‐phase flow in sieve plate packing.

Exergy analysis and parameter optimization of sinter cooling process in vertical moving bed for waste heat recovery

A steady-state mathematical model is proposed to investigate the sinter cooling process in vertical moving bed, and the optimal parameter combination of vertical tank (VT) is obtained based on the maximum enthalpy exergy of cooling air (EECA) through the method of orthogonal experiment. The results show that, the air outlet temperature increases with increasing the air inlet temperature, bed inner diameter and height, and decreasing the air flow rate. The gas flow pressure drop basically increases linearly with increasing the air flow rate, air inlet temperature and bed height, and decreases exponentially with increasing the bed inner diameter. EECA can reach the maximum value with the increase of air flow rate and air inlet temperature. When the air flow rate exceeds a certain limit value, EECA also has a maximum value with the increase of bed height, while there is not a turning point for the change curve of EECA with the bed inner diameter. Taking the actual annual output of 360 m2 sintering machine as the research object, the optimal parameter combination of VT is 9 m for the bed inner diameter, 8 m for the bed height, 353 K for the air inlet temperature and 180 kg/s for the air flow rate, respectively.

Theoretical and experimental investigation on vertical tank technology for sinter waste heat recovery

In the present work, the gas flow pressure drop and gas–solid heat transfer characteristics in sinter bed layer of vertical tank were studied experimentally on the basis of the homemade experimental setup. The gas flow pressure drop through the sinter bed layer was measured with different gas velocity and particle diameters, as well as the sinter and air temperatures. The influences of gas superficial velocity and particle diameter on the gas flow pressure drop and gas solid heat transfer in sinter bed layer were analyzed in detail. The revised Ergun’s correlation and gas solid heat transfer correlation were obtained according to the regression analysis of experimental data. It is found that, the pressure drop of unit bed layer height gradually increases as a quadratic relationship with increasing the gas superficial velocity, and decreases as an exponential relationship with the increase of sinter particle diameter. For a given sinter temperature, the heat transfer coefficient in sinter bed layer increases with increasing the gas superficial velocity, and increases with decreasing the sinter particle diameter. In addition, the heat transfer coefficient also gradually increases with increasing the sinter temperature at the same gas superficial velocity and sinter particle diameter. The mean deviations between the experimental data obtained from this work and the values calculated by the revised Ergun’s correlation and the experimental heat transfer correlation are 7.22% and 4.22% respectively, showing good prediction.

Model of Gas Permeability Coefficient in Capture Hydrodynamics for Anisotropic Materials

The results of hydrodynamic of gas flow through various type of porous material kind of coal-char are presented. With respect to hydrodynamics the studies have focused on the evaluation of the permeability of such materials as a resulting from the gas flow pressure drop. It allowed determining the permeability coefficient and the pressure drop coefficient, too. Due to anisotropic structure of carbonizers the examination were performed with respect to the flow direction, i.e. directivity permeability, as a result of three-dimensional orientation for each materials sample. The results of measurements indication strongly diversified hydrodynamic parameters for investigated types of materials, and comparison of test results leads to a conclusions that the main reason of this is clear of anisotropic structure of carbonizers. In order to obtain the wider description of microstructure process conditions as the hydrodynamic result of gas flow through porous materials, attempted to use the numerical method to assessment of this process. Numerical modeling indicated the concept of gas flow through porous a tortuous structure of microchannels and micropores, together forming a porous structure with a specific geometry – both an elementary unit constituting the porous layer-bed.

Gas-focused liquid microjets from a slit

We report an experimental study on a new arrangement of flow focusing that uses a slit aperture. The slit can achieve similar flow chocking function as a classic circular aperture to established gas flow pressure drop. Fundamentally, the jetting mechanism and quantitative behavior of slit flow focusing are very similar to the classic flow focusing because of the singularity nature of the jet despite the drastically different aperture shapes. After re-scaling the jet shape, the axial coordinate with the hydraulic diameter of the slit, the experimental data follow closely with the universal jet profile derived in Gañán-Calvo, Ferrera, and Montanero [“Universal size and shape of viscous capillary jets: Application to gas-focused microjets,” J. Fluid Mech. 670, 427-438 (2011)] based on circular aperture. Practically, the slit configuration expands the possibility of manipulating the jets. The two thin plates that form the slit aperture can also be used as electrodes to apply electrohydrodynamic excitation to the jet for controlled jet breakup with narrower droplet size distribution. In addition, the modest throughput of a single flow focused jet can be increased by operating a linear array of jets focused and excited by the same slit.

Numerical simulation of slugging of stagnant liquid at a V-shaped elbow in a pipeline

Numerical simulation of slugging of a stagnant liquid at a V-shaped elbow in a hilly-terrain pipeline is carried out using a three-dimensional two-fluid model. The free surface treatment for the interfacial area density is employed to describe the interaction between the phases. Comparisons with experimental data show that this numerical model is able to simulate slug development from static puddle. The onset of slugging is also predictable with reasonable accuracy. The mechanism of the onset of slugging is discussed based on the numerical predictions. The predictions make it clear that the pressure drop of gas flow at the V-shaped elbow induces the difference in the liquid level between upstream and downstream regions of the V-shaped elbow, which is the major trigger of the onset of slugging of stagnant liquid at the V-shaped elbow.

The role of the gas diffusion layer on slug formation in gas flow channels of fuel cells

Water drops emerge from large pores of the hydrophobic Gas Diffusion Layers (GDL) into the cathode gas flow channel of Polymer Electrolyte Membrane (PEM) Fuel Cells. The drops grow into slugs that span the cross-section of the flow channels. The slugs detach and are forced out the gas flow channel by the air flow. An acrylic micro-fluidic flow cell with a 1.6 mm gas flow channel and a 100 μm liquid pore through a carbon paper GDL has been used to quantitatively determine slug volumes, velocity of slug motion, and the force required to move slugs as functions of the gas and liquid flow rates. In a channel with 4 acrylic walls, slugs detach immediately upon formation. A porous GDL wall allows gas flow to bypass the slugs, thus allowing slugs to continue to grow after spanning the open area of the channel. The differential pressure to detach and move slugs is equal to the dynamic interfacial force on a slug normalized by the cross-sectional area of the channel. The dynamic interfacial force is equal to the difference between the downstream (advancing) and upstream (receding) contact lines of the water with the channel walls. Slugs will stop moving if the differential pressure drop for gas flow to bypass the slug and flow through the GDL under the rib separating the channels is less than the differential pressure required to move the slug. The results improve our physical insight into the state of water hold up in PEM fuel cells.

Investigation on interface resistance between alternating layers in the upper of blast furnace

Abstract In order to mitigate CO 2 emissions from steel industry, decreasing coke rate by establishing oxygen blast furnace ironmaking process is a favorable way. Yet every improvement in productivity is fundamentally related to better flow distribution of gas across a particle bed and hence total pressure drop in granular zone is a leading parameter affected by interfacial resistance between alternating layers of coke and metallic burden. In this work, the existence and change rule of interface resistance with different parameters such as flow rate, interface numbers, layer thickness are confirmed. A new pore-throat equation proposed by J.S. Wu and B.M. Yu [30] is imported to study pressure drop of gas flow through stock column in blast furnace and compared with well-known Ergun's equation. Furthermore, the relationships between interface resistance and physical parameters involved in this study is explored and combined with this new pore-throat equation to be a new modified equation. Meanwhile, its adaptability is verified for various conditions. On the basis of modified equation, interfacial porosity with flow rate is discussed and linked to microphenomenon of previous work and achievement of other researchers.

A Two-Stage Wood Chip-Based Biofilter System to Mitigate Odors from a Deep-Pit Swine Building

A mobile biofilter testing laboratory was developed where two-stage biofilters filled with western cedar and hardwood chips were examined to treat odor emissions from a deep-pit swine finishing facility in central Iowa. An automatically controlled water supply system was tested and used to control media moisture content. Odor concentrations from theinlet and biofilter treatments, gas flow pressure drop, leachate pH and ammonia concentration, and water consumption were monitored.Results indicate that the water supply system tested in this study can keep wood chip media at a high and stablemoisture content of 72% 3% (western cedar) and 62% 3% (hardwood)with a 6.4 L/m3-day water supply. Western cedar (WC) chips achieved an average reduction efficiency of 51%, 83%, and 41% for odor, H2S, and NH3, respectively, when keeping the WC moisture content at 72% and the empty bed residence time (EBRT) between 3.7 and 5.5 s. A linear relationship between media unit pressure drop and unit airflow rate was observed with two-stage biofilters having an advantage in potentially reducing media compaction.Leachate pH and NH3 concentration were measured with pH levels in the 7.2 to 7.9 range with the NH3 concentration in the 198 to 1300 mg/L as N range.The effects of three different levels of media moisture content shows that proper moisture content is a key factor for the success of wood chip biofilters, but is not a substitute for inadequate EBRT.

CFD simulation and experimental study for two-phase flow through the trickle bed reactors, sock and dense loaded by trilobe catalysts

In this study single and two phase flow through the trickle bed reactor loaded with a two different loading manner, sock and dense, have been investigated numerically and experimentally. The CT-scan imaging and an image processing code have been used for investigation of radial porosity distribution of trilobe catalyst in sock and dense loading procedure in trickle bed reactors and two different correlations have been proposed. These correlations were used in a single and two phase CFD code for prediction of pressure drop of gas flow in dry and prewet trilobe catalyst packed bed and also pressure drop and dynamic liquid holdup for two phase flow. In addition, these variables were studied experimentally with a laboratory scale trickle bed reactor. The results of CFD simulations show a very good agreement with experimental data.

Treatment of Propylene Glycol Monomethyl Ether Acetate in Air Streams by a Biofilter Packed with Fern Chips

This study aimed to develop a biofilter packed only with fern chips for the removal of airborne propylene glycol monomethyl ether acetate (PGMEA). Fern chips could avoid the shortcomings of traditional media, such as compaction, drying, and breakdown, which lead to the performance failure of the biofilters. In addition, the fern chip medium has the following merits: (1) simplicity in composition; (2) low pressure drop for gas flow (<20 mmH2O∙m-1); (3) simple in humidification, nutrient addition, pH control, and metabolite removal; (4) economical (US$174–385∙m-3), and (5) low weight (wet basis around 290 kg∙m-3). A two-stage downflow biofilter (2.18 m in height and 0.4×0.4 m in cross-sectional area) was constructed for the performance test. Both stages were packed with fern chips of 0.30 m in height and 0.40×0.40 m in cross-section. Results indicate that with operation conditions of media moisture content controlled in the range of 50–74%, media pH of 6.5–8.3, empty bed retention time (EBRT) of 0.27–0.4 min, influent PGMEA concentrations of 100–750 mg∙m-3, volu-metric organic loading of <170 ∙m-3 ∙hr-1, and nutrition rates of Urea-nitrogen 66 g∙m-3 ∙day-3, potassium dihydrogen phosphate (KH2PO4)-phosphorus 13.3 g ∙m-3 ∙day-3, and milk powder 1.00 g∙m-3∙day-1, the fern-chip-packed biofilter could achieve an overall PGMEA removal efficacy of around 94%. Instant milk powder or liquid milk was essential to the good and stable performance of the biofilter for PGMEA removal.

Low-temperature filtration of gases using multilayer cermet filters

The performance characteristics of highly efficient cermet filters with a multilayer membrane structure used for the treatment of nitrogen, argon, helium, methane, carbon monoxide and dioxide at temperatures up to 75 K are studied. It is shown that as the temperature decreases, their collection efficiency with respect to a finely dispersed aerosol decreases. At low Reynolds numbers, the variation of the gas-flow pressure drop through the filters is determined by the gas viscosity. The multilayer nickel-based membrane structure is stable to substantial temperature gradients and can be regenerated by blowing and heating. It is found that the filter collection efficiency for liquid gases is determined by the pore size of the fine-pore selective layer of the filters according to the sieving mechanism of collecting dispersed particles.

Removal of mixtures of acetaldehyde and propionaldehyde from waste gas in packed column with immobilized activated sludge gel beads

The removal of mixed acetaldehyde and propionaldehyde as a model of the binary contaminants in waste gas was studied in the packed column containing the immobilized activated sludge gel beads together with the hollow plastic balls developed for the removal of a single aldehyde in the previous work. The rate of each aldehyde biodegradation by the gel beads in the aldehydes mixture was expressed by the Michaelis–Menten type rate equation with an inhibitory term due to the other coexistent aldehyde. The kinetic parameters involved were found to be the same as those determined previously for biodegradation of a single aldehyde. A model for prediction of removal of each aldehyde in the packed column was developed assuming that each aldehyde dissolved in the aqueous phase within the gel bead was biodegraded according to the above rate equation with no mass transfer effect. The packed column was stable and efficient for removal of the binary aldehydes mixture with a very low pressure drop for gas flow due to a reduced gel beads bed compaction by the hollow plastic balls. Removal of each aldehyde decreased with increasing the inlet aldehyde concentrations since each biodegradation rate itself approached asymptotically the maximum one with increase in each aldehyde concentration. The observed removals for each aldehyde in the aldehydes mixture agreed well with those calculated from the design equations developed. The contact efficiency of gel beads with the waste gas stream was estimated to be the same value of 0.24 as in the previous work, supporting that the efficiency was specific to the geometrical and physical properties of the packed column used.