Blowout Limits of a Jet Diffusion Flame in the Presence of Small Surrounding Jet Pilot Flames

1996 ◽  
Vol 118 (2) ◽  
pp. 140-144
Author(s):  
M. G. Kibrya ◽  
G. A. Karim
Keyword(s):  
Flow Rate ◽  
Diffusion Flame ◽  
Operating Parameters ◽  
Jet Flames ◽  
Jet Flame ◽  
Flowing Stream

The blowout limit of a methane jet diffusion flame is examined in the presence of a number of much smaller pilot jet flames of different fuels arranged within an experimental burner assembly in a co-flowing stream of air. It is shown that the blowout limit of the central jet flame can be extended very appreciably by increasing the flow rate through the smaller pilot jets. The basis for this extension to the blowout limit and the role of some changes in the operating parameters are discussed. It is suggested that the extension to the blowout limit observed is due mainly to the thermal contribution of the pilot jet flames.

scholarly journals Effects of Operating Parameters on Ionic Liquid Membrane to Remove Humidity in a Green Continuous Process

Membranes ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 65
Author(s):  
Xueru Yan ◽  
Alexandre Favard ◽  
Stéphane Anguille ◽  
Marc Bendahan ◽  
Philippe Moulin
Keyword(s):  
Ionic Liquid ◽  
Flow Rate ◽  
Continuous Process ◽  
Hybrid Process ◽  
Absolute Pressure ◽  
Mechanical Resistance ◽  
Operating Parameters ◽  
Separation Performance ◽  
Feed Concentration ◽  
Time Operation

Membrane processes are promising methods to separate gases from feed streams without phase changing. A hybrid process, the combination of ionic liquids with a ceramic membrane (ILM), has been developed for humidity removal in a green continuous process. This new concept provides a more efficient and available ionic liquid (IL)-based membrane regeneration process, which just switches the moist feed stream to dry air. Furthermore, the ILM presents high stability and mechanical resistance during long-time operation. In addition, the influences of several operating parameters, including flow rate, temperature, absolute pressure, and feed concentration on process efficiency were investigated. The lower inlet flow rate was found to be favorable for drying humid air. Moreover, when the pressure increased, the mass of absorbed water was increased, while the feed concentration had no significant effects on the membrane separation performance. However, the operating temperature had a great effect on humidity removal. It is necessary to note that the processes at room temperature can limit the energy consumption. The absorbing process of ILM remained efficient after several absorption desorption cycles. Therefore, the new ILM hybrid process that has been developed has great potential for consecutive humidity removal processes.

scholarly journals Role of Shearing Dispersion and Stripping in Wax Deposition in Crude Oil Pipelines

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4325
Author(s):  
Zhihua Wang ◽  
Yunfei Xu ◽  
Yi Zhao ◽  
Zhimin Li ◽  
Yang Liu ◽  
...  
Keyword(s):  
Crude Oil ◽  
Flow Rate ◽  
Critical Flow ◽  
Wax Deposition ◽  
Dominant Effect ◽  
Critical Flow Rate ◽  
Oil Pipelines ◽  
Oil Flow ◽  
Shearing Mechanism

Wax deposition during crude oil transmission can cause a series of negative effects and lead to problems associated with pipeline safety. A considerable number of previous works have investigated the wax deposition mechanism, inhibition technology, and remediation methods. However, studies on the shearing mechanism of wax deposition have focused largely on the characterization of this phenomena. The role of the shearing mechanism on wax deposition has not been completely clarified. This mechanism can be divided into the shearing dispersion effect caused by radial migration of wax particles and the shearing stripping effect caused by hydrodynamic scouring. From the perspective of energy analysis, a novel wax deposition model was proposed that considered the flow parameters of waxy crude oil in pipelines instead of its rheological parameters. Considering the two effects of shearing dispersion and shearing stripping coexist, with either one of them being the dominant mechanism, a shearing dispersion flux model and a shearing stripping model were established. Furthermore, a quantitative method to distinguish between the roles of shearing dispersion and shearing stripping in wax deposition was developed. The results indicated that the shearing mechanism can contribute an average of approximately 10% and a maximum of nearly 30% to the wax deposition process. With an increase in the oil flow rate, the effect of the shearing mechanism on wax deposition is enhanced, and its contribution was demonstrated to be negative; shear stripping was observed to be the dominant mechanism. A critical flow rate was observed when the dominant effect changes. When the oil flow rate is lower than the critical flow rate, the shearing dispersion effect is the dominant effect; its contribution rate increases with an increase in the oil flow temperature. When the oil flow rate is higher than the critical flow rate, the shearing stripping effect is the dominant effect; its contribution rate increases with an increase in the oil flow temperature. This understanding can be used to design operational parameters of the actual crude oil pipelines and address the potential flow assurance problems. The results of this study are of great significance for understanding the wax deposition theory of crude oil and accelerating the development of petroleum industry pipelines.

Research on the Removal Results of Hydrogen Sulfide of the Treatment of Coal Gasification Wastewater Biogas in the Anaerobic Biotrickling Filter

2012 ◽  
Vol 610-613 ◽  
pp. 2000-2005
Author(s):  
Chun Yan Xu ◽  
Hong Jun Han
Keyword(s):  
Hydrogen Sulfide ◽  
Removal Efficiency ◽  
Flow Rate ◽  
Retention Time ◽  
Operating Parameters ◽  
Inlet Flow ◽  
H2s Removal ◽  
Outlet Concentration ◽  
Volume Load ◽  
Inlet Flow Rate

The uncertainty of operating parameters hinders the practical application of the biological desulfurization. To solve this problem, this study which was conducted in room temperature, pH around seven conditions, investigated the effects of the operating parameters on the hydrogen sulfide (H2S) removal performance in the biotrickling filter, including inlet H2S concentration, inlet flow rate or gas retention time, inlet volume load and circulating liquid spraying flux. The results showed that, the inlet H2S concentration should be controlled within 800mg/m3, 650mg/m3, 400mg/m3, 300mg/m3 respectively while the inlet flow rate was 150L/h, 200L/h, 250L/h, 300L/h, at those conditions, the outlet H2S concentrations were lower than 8mg/m3 and the H2S removal efficiencies were more than 98%. The optimum gas retention time was 12.37s, corresponding to the inlet flow rate of 200L/h, at this time, even if the inlet H2S concentration as high as 700mg/m3, the removal efficiency could be still more than 98%, the outlet concentration of H2S was only 13.1mg/m3. The maximum inlet volume load was 130g/(m3•h), in this condition, the outlet concentration of H2S could be controlled below 12mg/m3, the removal efficiency could above 98.4%.

Influence of Burner Material, Tip Temperature, and Geometrical Flame Configuration on Flashback Propensity of H2-Air Jet Flames

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Zhixuan Duan ◽  
Brendan Shaffer ◽  
Vincent McDonell ◽  
Georg Baumgartner ◽  
Thomas Sattelmayer
Keyword(s):  
Jet Flames ◽  
Comprehensive Overview ◽  
High Hydrogen ◽  
Jet Flame ◽  
Practical Applications ◽  
Geometric Configurations ◽  
Air Jet ◽  
Low Emission ◽  
Flame Burner ◽  
Negative Impacts

Flashback is a key operability issue for low emission premixed combustion systems operated on high hydrogen content fuels. Previous work investigated fuel composition impacts on flashback propensity and found that burner tip temperature was important in correlating flashback data in premixed jet flames. An enclosure around the jet flame was found to enhance the flame–burner rim interaction. The present study further addresses these issues using a jet burner with various geometric configurations and interchangeable materials. Systematic studies addressing the quantitative influence of various parameters such as tip temperature, burner material, enclosure size, and burner diameter on flashback propensity were carried out. A comprehensive overview of the flashback limits for all conditions tested in the current study as well as those published previously is given. The collective results indicate that the burner materials, tip temperature, and flame confinement play significant roles for flashback propensity and thus help explain previous scatter in flashback data. Furthermore, the present work indicates that the upstream flame propagation during flashback is affected by the burner material. The material with lower thermal conductivity yields larger flashback propensity but slower flame regression inside the tube. These observations can be potentially exploited to minimize the negative impacts of flashback in practical applications.

scholarly journals Foaming of industrial lean methyldiethanolamine solution in the presence of hydrocarbon and fatty acid based corrosion inhibitors

2018 ◽  
Vol 73 ◽  
pp. 76 ◽  
Author(s):  
Mohammad Keewan ◽  
Fawzi Banat ◽  
Priyabrata Pal ◽  
Jerina Zain ◽  
Emad Alhseinat
Keyword(s):  
Fatty Acid ◽  
Pore Size ◽  
Corrosion Inhibitor ◽  
Flow Rate ◽  
Gas Flow ◽  
Corrosion Inhibitors ◽  
Liquid Volume ◽  
Operating Parameters ◽  
Time Flow ◽  
Foaming Time

In natural gas sweetening alkanolamine processes one of the regularly used chemical is the corrosion inhibitor. For better operation of the plant it is essential to understand the effect of their presence on foaming of industrial lean Methyldiethanolamine (MDEA) used as solvents at different temperatures. This study aimed at investigating the effect of HydroCarbon Based (HCB) and fatty acid based corrosion inhibitor having chemical name Bis(2-Hydroxyethyl)Cocoalkylamine (BHCL) on the foaming tendency of industrial real lean MDEA solutions. Experiments were conducted with different operating parameters, including liquid volume of the solution, foaming time, flow rate of nitrogen gas, concentration of the corrosion inhibitors, temperature of the solution, and gas diffuser pore size using the Foam Scan instrument. With the increase in solution volume and foaming time foaming happens to be more. The foaming tendency of lean MDEA solutions decreased with increasing temperature in absence of corrosion inhibitors but showed different behavior in their presence. At small diffuser pore size and high gas flow rate, the final foam volume increased in the presence of HCB but decreased with the BHCL inhibitor. Optimizing the operating parameters to minimize foaming was verified to be a function of the type of inhibitor used.

Role of oxygen flow rate on the structure and stoichiometry of cobalt oxide films deposited by reactive sputtering

2022 ◽  
Vol 40 (1) ◽  
pp. 013405
Author(s):  
Nilton Francelosi A. Neto ◽  
Cristiane Stegemann ◽  
Lucas J. Affonço ◽  
Douglas M. G. Leite ◽  
José H. D. da Silva
Keyword(s):  
Cobalt Oxide ◽  
Flow Rate ◽  
Oxide Films ◽  
Reactive Sputtering ◽  
Oxygen Flow Rate ◽  
Oxygen Flow

Relationships between pressure and flow across the gastroduodenal junction in dogs

1991 ◽  
Vol 260 (4) ◽  
pp. G653-G657 ◽  
Author(s):  
C. H. Malbert ◽  
Y. Ruckebusch
Keyword(s):  
Flow Rate ◽  
Temporal Relationship ◽  
Conscious Dogs ◽  
Transpyloric Flow ◽  
Gastric Contents ◽  
Mechanical Factors

Antroduodenal pressure events were measured simultaneously with transpyloric flow, in conscious dogs, to evaluate the role of mechanical factors modulating this flow. The relationships between pressure and flow across the gastroduodenal junction were never linear. During the interdigestive state, terminal antral contraction occurred 0.9 +/- 0.29 s after the onset of the gush of gastric contents. Hence, the highest flow rate occurred during the period of lowest resistance. After a meal, terminal antral contraction began 3.3 +/- 0.87 s before the flow of chyme, and resistance rose simultaneously with flow rate. The antroduodenal resistance was 10 times higher than during the interdigestive state (8.33 +/- 1.56 vs. 0.73 +/- 0.34 mmHg.ml-1.s). The pyloroduodenal resistance was always lower than the antropyloric one. It is concluded that, because of the temporal relationship between motor events and flow, pure resistive behavior of the junction occurred only after a meal.

Effects of vasopressin administration on diuresis of water immersion in normal humans

1981 ◽  
Vol 51 (6) ◽  
pp. 1384-1387 ◽  
Author(s):  
M. Epstein ◽  
A. G. DeNunzio ◽  
R. D. Loutzenhiser
Keyword(s):  
Antidiuretic Hormone ◽  
Flow Rate ◽  
Water Immersion ◽  
Normal Subjects ◽  
Urinary Flow Rate ◽  
Urinary Flow ◽  
Relative Role ◽  
Normal Humans

Although previous studies have demonstrated that water immersion to the neck (NI) results in a significant diuresis, the mechanisms are incompletely delineated. Because recent studies in our laboratory have demonstrated that NI is associated with a suppression of antidiuretic hormone (ADH), it is possible that such a suppression mediates the encountered diuresis. The present study was undertaken to assess more directly the relative role of ADH suppression by determining the effects of vasopressin administration. Six hydrated normal subjects were studied on two occasions while undergoing 6 h of NI. During the second NI study, aqueous vasopressin (20 mU/h) was infused for the initial 4 h of study (NI + vasopressin). NI resulted in a significant increase in urinary flow rate beginning during hour 1 and persisting throughout NI. In contrast, during NI + vasopressin, the anticipated diuresis was abolished throughout the 4 h of vasopressin administration. Cessation of vasopressin administration during the final 2 h of NI + vasopressin resulted in a marked and prompt diuresis. The present observations are consistent with the formulation that ADH suppression participates importantly in mediating the diuresis of NI in hydrated normal subjects.

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