EFFECTS OF CHOKE RING DIMENSION ON THERMAL AND FLUID FLOW IN A SRU THERMAL REACTOR

2016 ◽  
Vol 40 (4) ◽  
pp. 511-520 ◽  
Author(s):  
Chun-Lang Yeh
Keyword(s):  
Fluid Flow ◽  
Temperature Region ◽  
Oxygen Supply ◽  
Skin Friction Coefficient ◽  
Thermal Reactor ◽  
Sulfur Recovery ◽  
Sulfur Concentration ◽  
Average Temperature ◽  
The Rich ◽  
Lower Temperature

The effects of choke ring dimension on the thermal and fluid flow in a practical SRU (sulfur recovery unit) thermal reactor are investigated numerically. It is found that zone 1 is a higher temperature region. In contrast, zone 2 is a lower temperature region. The average temperature for the rich oxygen supply is higher than that of normal oxygen supply. Without a choke ring, the temperature difference between zone 1 and zone 2 is smaller and the temperature in zone 1 becomes lower while the temperature in zone 2 becomes higher. In addition, the average temperature in zone 1 and the sulfur concentration at exit are the lowest without a choke ring. The reactor with a choke ring height of 0.74 m has the lowest peak temperature and the largest sulfur concentration at exit. Finally, with a choke ring height of 1.11 m, the blockage effect of the choke ring leads to the largest peak skin friction coefficient.

NUMERICAL ANALYSIS OF THE EFFECTS OF STREAMLINING GEOMETRY AND A VECTOR WALL ON THE THERMAL AND FLUID FLOW IN A SRU THERMAL REACTOR

2016 ◽  
Vol 40 (5) ◽  
pp. 811-820 ◽  
Author(s):  
Chun-Lang Yeh
Keyword(s):  
Fluid Flow ◽  
Recirculation Zone ◽  
Skin Friction Coefficient ◽  
Peak Temperature ◽  
Thermal Reactor ◽  
Radius Of Curvature ◽  
Average Temperature ◽  
Compression Effect ◽  
High Temperature Operation ◽  
Optimal Radius

To resolve the abnormality of a SRU thermal reactor under high temperature operation and to improve the recovery of sulfur, the effects of streamlining geometry and a vector wall on the thermal and fluid flow in a SRU thermal reactor are investigated numerically. It is found that the compression effect caused by a streamlined zone 1 corner leads to an increase in the average temperature. However, the corner recirculation zone using a streamlined zone 1 corner becomes smaller and this yields a reduction in temperature. The combined effect of compression and a smaller corner recirculation zone leads to an optimal radius of curvature at the zone 1 corner. The lowest peak temperature is obtained using a radius of curvature 1m at the zone 1 corner. With larger radii of curvature at the zone 1 corner, the compression effect overwhelms the effect of a smaller corner recirculation zone and the peak temperature is higher. The specific arrangement of the vector wall holes results in a spiral motion behind the vector wall. The average temperature increases and becomes more uniform across a vector wall. The peak temperature and the exit sulfur concentration are higher using a vector wall. Finally, the skin friction coefficient increases abruptly across a vector wall but becomes lower downstream, compared with using a choke ring. The results of this paper are helpful in improving the performance and safety of a SRU thermal reactor.

THE EFFECTS OF INLET AIR QUANTITY AND INLET OXYGEN MOLE FRACTION ON THE COMBUSTION AND FLUID FLOW IN A SULFUR RECOVERY UNIT THERMAL REACTOR

2017 ◽  
Vol 41 (2) ◽  
pp. 293-300 ◽  
Author(s):  
Chun-Lang Yeh
Keyword(s):  
Fluid Flow ◽  
High Temperature ◽  
Mole Fraction ◽  
Thermal Reactor ◽  
Sulfur Recovery ◽  
Economical Method ◽  
Sulfur Recovery Unit ◽  
Recovery Unit ◽  
Field Temperature ◽  
High Temperature Operation

Owing to the high temperature inside a sulfur recovery unit (SRU) thermal reactor, detailed experimental measurements are difficult. In the author’s previous studies, several methods have been assessed to resolve the abnormality of the SRU thermal reactor under high temperature operation. This paper presents a new easier and more economical method. The effects of inlet air quantity and inlet O2 mole fraction on the combustion and fluid flow in a SRU thermal reactor are investigated numerically. The flow field temperature, S2 recovery, H2S mole fraction, and SO2 emissions are analyzed. This paper provides a guideline for adjusting the inlet air quantity and the inlet O2 mole fraction to reduce the high temperature inside a thermal reactor and to ensure an acceptable sulfur recovery.

scholarly journals Numerical study of the burner parameters on the thermal field in a sulfur recovery unit thermal reactor

2018 ◽  
Vol 169 ◽  
pp. 01013
Author(s):  
Chun-Lang Yeh
Keyword(s):  
High Temperature ◽  
Mole Fraction ◽  
Thermal Field ◽  
Numerical Study ◽  
Thermal Reactor ◽  
Sulfur Recovery ◽  
Acid Gas ◽  
Sulfur Recovery Unit ◽  
Recovery Unit ◽  
Lower Temperature

A sulfur recovery unit (SRU) thermal reactor is the most important equipment in a sulfur plant and is negatively affected by high temperature operations. In this paper, the effect of burner parameters, including the clearance of the acid gas tip and the inlet air swirler angle, on the thermal field in a SRU thermal reactor are investigated numerically, with the aim to reduce the high temperature inside the thermal reactor and to ensure an acceptable sulfur recovery. The simulation results show that the burner with a smaller clearance of the acid gas tip produces a lower temperature, a lower exit SO2 mole fraction and higher exit S2 and H2S mole fractions. Among the clearancs of the acid gas tip investigated, the horizontal clearance of 152.4mm and vertical clearance of 240mm yield the lowest temperature, exit SO2 mole fraction and highest exit S2, H2S mole fractions. The burner with a smaller inlet air swirler angle produces a higher temperature, a higher exit SO2 mole fraction and lower exit S2 and H2S mole fractions. Among the swirler angles investigated, 60° yields the lowest temperature, exit SO2 mole fraction and highest exit S2 , H2S mole fractions.

scholarly journals A novel formulation of 3D Jeffery fluid flow near an irregular permeable surface having chemical reactive species

2021 ◽  
Vol 13 (5) ◽  
pp. 168781402110136
Author(s):  
Mumtaz Khan ◽  
Amer Rasheed ◽  
Shafqat Ali ◽  
Qurat-ul-Ain Azim
Keyword(s):  
Fluid Flow ◽  
Variable Thickness ◽  
Mass Transfer Rate ◽  
Skin Friction Coefficient ◽  
Deborah Number ◽  
Pictorial Representation ◽  
Fluid Temperature ◽  
Flow Parameters ◽  
Opposite Behavior ◽  
Thickness Parameter

The main objective of this paper is to offer a comprehensive study regarding solar radiation and MHD effects on 3D boundary layer Jeffery fluid flow over a non-uniform stretched sheet along with variable thickness, porous medium and chemical reaction of first order are assumed. The system of equations representing temperature, velocity and concentration fields are converted into dimensionless form by introducing dimensionless variables. Thereafter, the aforesaid equations are solved with the help of BVP4C in MATLAB. The numerical results obtained through this scheme are more accurate when compared with those in the existing literature. In order to have a pictorial representation, the effects of material and flow parameters on velocity, temperature and concentration profiles are presented through graphs. Moreover, the numerical values of heat and mass transfer rate and skin friction coefficient are given in tabular form. It is evident from the acquired results, that the velocity offers two fold behavior for variable thickness parameter that is, n < 1 close and away from the non-uniform surface. It is also noted that the axial and transverse velocities show an increasing behavior for Deborah number while the fluid temperature and concentration shows opposite behavior at the same time.

Interactions between cellular respiration and thermoregulation in the paramecium

1994 ◽  
Vol 267 (1) ◽  
pp. R349-R352 ◽  
Author(s):  
G. M. Malvin ◽  
P. Havlen ◽  
C. Baldwin
Keyword(s):  
Oxidative Phosphorylation ◽  
Thermal Gradient ◽  
Oxygen Supply ◽  
Cellular Respiration ◽  
Maximal Response ◽  
Adaptation To Hypoxia ◽  
Cellular Mechanisms ◽  
Beneficial Response ◽  
Lower Temperature ◽  
Maximal Reduction

An important adaptation to hypoxia is a regulated reduction in body temperature because it lowers metabolic rate when oxygen supply is limited. Although this beneficial response occurs in organisms ranging from protozoans to mammals, little is known of the cellular mechanisms responsible for the hypoxia-induced reduction in temperature. Using the unicellular protozoan, Paramecium caudatum, we showed that inhibition of oxidative phosphorylation with sodium azide (NaN3) under normoxic conditions mimics the thermoregulatory effects of hypoxia, causing this species to select a lower temperature in a thermal gradient (P < 0.0001). Under control conditions, selected temperature (Tsel) was 28.3 +/- 0.3 degrees C. NaN3 concentrations of 0.1 mM and above significantly reduced Tsel (P < 0.0001). Ten millimolar NaN3 produced the maximal reduction in Tsel, 11.4 degrees C, and the dose that produced 50% of the maximal response was 0.7 mM. The reduction in temperature was beneficial because both O2 consumption and survival were significantly less affected by NaN3 at lower temperatures. These results suggest that O2 does not directly affect thermoregulation in the paramecium. Rather, the hypoxia-induced reduction in Tsel results from inhibition of oxidative phosphorylation.

scholarly journals Effect of chemical composition on the electrical conductivity of gneiss at high temperatures and pressures

Solid Earth ◽  
2018 ◽  
Vol 9 (2) ◽  
pp. 233-245 ◽  
Author(s):  
Lidong Dai ◽  
Wenqing Sun ◽  
Heping Li ◽  
Haiying Hu ◽  
Lei Wu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Temperature Region ◽  
Ionic Conduction ◽  
Complex Impedance ◽  
Weight Percent ◽  
Spectroscopic Technique ◽  
Ultrahigh Pressure ◽  
Chemical Compositions ◽  
Metamorphic Belt ◽  
Lower Temperature

Abstract. The electrical conductivity of gneiss samples with different chemical compositions (WA = Na2O + K2O + CaO  =  7.12, 7.27 and 7.64 % weight percent) was measured using a complex impedance spectroscopic technique at 623–1073 K and 1.5 GPa and a frequency range of 10−1 to 106 Hz. Simultaneously, a pressure effect on the electrical conductivity was also determined for the WA = 7.12 % gneiss. The results indicated that the gneiss conductivities markedly increase with total alkali and calcium ion content. The sample conductivity and temperature conform to an Arrhenius relationship within a certain temperature range. The influence of pressure on gneiss conductivity is weaker than temperature, although conductivity still increases with pressure. According to various ranges of activation enthalpy (0.35–0.52 and 0.76–0.87 eV) at 1.5 GPa, two main conduction mechanisms are suggested that dominate the electrical conductivity of gneiss: impurity conduction in the lower-temperature region and ionic conduction (charge carriers are K+, Na+ and Ca2+) in the higher-temperature region. The electrical conductivity of gneiss with various chemical compositions cannot be used to interpret the high conductivity anomalies in the Dabie–Sulu ultrahigh-pressure metamorphic belt. However, the conductivity–depth profiles for gneiss may provide an important constraint on the interpretation of field magnetotelluric conductivity results in the regional metamorphic belt.

scholarly journals Seasonal Trends in the Occurrence of Eclampsia

2014 ◽  
Vol 6 (2) ◽  
pp. 83-87
Author(s):  
Ahmad Malik ◽  
Shaheen Kausar ◽  
Alia Bashir ◽  
Mamoon Akbar Qureshi
Keyword(s):  
Atmospheric Pressure ◽  
Meteorological Data ◽  
Barometric Pressure ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Seasonal Trends ◽  
Weather Patterns ◽  
Average Temperature ◽  
Lower Temperature ◽  
Study Setting

ABSTRACT Background Preeclampsia and eclampsia are major obstetric complications with unclear etiologies. Understanding the exact association with different weather patterns may help us in understanding what factors may be involved in triggering these events. Lower temperature, higher humidity and lower barometric pressure are linked to eclampsia. Objective To know the relation between variations of weather and incidence of eclampsia in patients presenting in, Jinnah Hospital, Lahore. Materials and methods Total number of deliveries and patients presenting with eclampsia were recorded from January 2008 to December 2012. Meteorological data was acquired from the regional meteorological center recording the monthly average temperature, humidity, barometric pressure and rainfall during the study period. The incidence of eclampsia and the seasonal trend were analyzed for Maximum (MMM) temperature, humidity at 5 pm, 5 pm atmospheric pressure (ATM) and rainfall. Study design Cross sectional study Study setting Gyne Unit 2, Jinnah Hospital, Lahore Results Over a 60-month period, a total of 31,331 deliveries were recorded, of which 579 patients developed eclampsia (1.85%). There was a statistically significant Pearson's correlation coefficient, the incidence of eclampsia was found to increase with MMM 5 pm temperature (0.516, p < 0.05) and rainfall (0.427, p < 0.05) and 5 pm ATM atmospheric pressure (—0.501, p < 0.05). No significant correlation was found with humidity (0.093, p > 0.05). Conclusion Incidence of eclampsia has direct linear relationship with increased temperature and rainfall and inverse relationship with 5 pm atmospheric pressure. The humidity had no apparent effect. How to cite this article Kausar S, Bashir A, Malik A, Qureshi MA. Seasonal Trends in the Occurrence of Eclampsia. J South Asian Feder Obst Gynae 2014;6(2):83-87.

Experimental Study on Conduction Heating of Ultra-High Strength Boron Steel

2014 ◽  
Vol 898 ◽  
pp. 185-188 ◽  
Author(s):  
Wei Kang Liang ◽  
Ming Lin Zhou ◽  
Hui Qiang Liu ◽  
Yi Sheng Zhang
Keyword(s):  
Energy Efficiency ◽  
Temperature Region ◽  
Rapid Heating ◽  
High Strength ◽  
Heating System ◽  
High Energy ◽  
Boron Steel ◽  
Uniform Temperature ◽  
Average Temperature ◽  
Conduction Heating

Conduction heating overcomes the shortage of the furnace, due to rapid heating and high energy efficiency. The heating experiment of ultra-high strength boron steel (LG1500HS) of a rectangular blank was implemented on the conduction heating system. The variations of the average temperature rising rate, uniform temperature region and energy efficiency were investigated under the non-heating-retaining condition. The results show that the average temperature rising rate, uniform temperature region and energy efficiency are 44.5°C/s, 225 mm and 71.6%, respectively.

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