Coke formation during the pyrolysis of hydrocarbons in the presence of sulphur compounds

1985 ◽  
Vol 50 (12) ◽  
pp. 2903-2909 ◽  
Author(s):  
Martin Bajus ◽  
Jozef Baxa
Keyword(s):  
Carbon Disulphide ◽  
Coke Formation ◽  
Steel Tube ◽  
Inhibition Mechanism ◽  
Stainless Steel Tube ◽  
Tube Flow ◽  
Sulphur Compounds ◽  
Dithiophosphoric Acid ◽  
Inhibiting Effect ◽  
Flow Through

The effect of 1-butanethiol, 0,0'-di-1-butyl dithiophosphate zinc, 0,0'-diethyl dithiophosphoric acid and carbon disulphide, respectively, on the formation of coke during the pyrolysis of a reformer raffinate at 820 °C and 100 kPa was studied using a stainless steel tube flow-through reactor. The sulphur compounds were added in amounts of 0.05 to 5.0 wt.%. The coke formation was followed from the beginning of the experiment. The coking rate was lower as compared with the pyrolysis of the pure reformer raffinate; 0,0'-di-1-butyl dithiophosphate zinc, 0,0'-diethyl dithiophosphoric acid and carbon disulphide have a strong inhibiting effect on the coke formation. The coking inhibition mechanism is discussed.

Effect of sulphur compounds on the heptane pyrolysis kinetics

1985 ◽  
Vol 50 (12) ◽  
pp. 2893-2902 ◽  
Author(s):  
Martin Bajus ◽  
Jozef Baxa
Keyword(s):  
Thermal Decomposition ◽  
Stainless Steel ◽  
Carbon Disulphide ◽  
Reaction Times ◽  
Pyrolysis Kinetics ◽  
Sulphur Compounds ◽  
Dithiophosphoric Acid ◽  
Tube Reactor ◽  
Flow Through ◽  
Steel Flow

The effect of 1-didecyl sulphide, diethyl disulphide, p,p'-dichlorodiphenyl disulphide, 1-butanethiol, 0,0'-di-1-butyl dithiophosphate zinc, 0,0'-diethyl dithiophosphoric acid and carbon disulphide, respectively, on the kinetics and selectivity of the thermal decomposition of heptane at 700 °C and 100 kPa was studied in a stainless steel flow-through tube reactor. The sulphur substance content was 0.1-1.0 wt.%. 1-Didecyl sulphide, p,p'-dichlorodiphenyl disulphide, 1-butylthiol, 0,0'-di-1-butyl dithiophosphate zinc and carbon disulphide favour the decomposition of heptane by 5-17%. A decrease in the heptane decomposition rate was observed in the presence of diethyl disulphide (2.8%) and 0,0'-diethyl dithiophosphoric acid (13.9%). The selectivity of decomposition to ethylene is increased by diethyl disulphide, p,p'-dichlorodiphenyl disulphide, carbon disulphide and 1-didecyl sulphide and, in the range of short reaction times, also by 0,0'-diethyl dithiophosphoric acid, 0,0'-di-1-butyl dithiophosphate zinc and 1-butanethiol.

scholarly journals Estimations on Properties of Redox Reactions to Electrical Energy and Storage Device of Thermoelectric Pipe (TEP) Using Polymeric Nanofluids

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1812
Author(s):  
Qin Gang ◽  
Rong-Tsu Wang ◽  
Jung-Chang Wang
Keyword(s):  
Thermal Conductivity ◽  
Power Density ◽  
Heat Dissipation ◽  
Electrical Energy ◽  
Steel Tube ◽  
Storage Device ◽  
Stainless Steel Tube ◽  
The Novel ◽  
Empirical Formulas ◽  
Dissipative Heat

A thermoelectric pipe (TEP) is constructed by tubular graphite electrodes, Teflon material, and stainless-steel tube containing polymeric nanofluids as electrolytes in this study. Heat dissipation and power generation (generating capacity) are both fulfilled with temperature difference via the thermal-electrochemistry and redox reaction effects of polymeric nanofluids. The notion of TEP is to recover the dissipative heat from the heat capacity generated by the relevant machine systems. The thermal conductivity and power density empirical formulas of the novel TEP were derived through the intelligent dimensional analysis with thermoelectric experiments and evaluated at temperatures between 25 and 100 °C and vacuum pressures between 400 and 760 torr. The results revealed that the polymeric nanofluids composed of titanium dioxide (TiO2) nanoparticles with 0.2 wt.% sodium hydroxide (NaOH) of the novel TEP have the best thermoelectric performance among these electrolytes, including TiO2 nanofluid, TiO2 nanofluid with 0.2 wt.% NaOH, deionized water, and seawater. Furthermore, the thermal conductivity and power density of the novel TEP are 203.1 W/(m·K) and 21.16 W/m3, respectively.

Transformations of hydrocarbon radicals moving along a stainless steel tube

2010 ◽  
Vol 4 (6) ◽  
pp. 928-934
Author(s):  
A. E. Gorodetskii ◽  
V. L. Bukhovets ◽  
R. Kh. Zalavutdinov ◽  
A. P. Zakharov
Keyword(s):  
Stainless Steel ◽  
Steel Tube ◽  
Stainless Steel Tube ◽  
Hydrocarbon Radicals

The Effects of Nucleate Boiling Versus Film Boiling on Heat Transfer in Power Boiler Tubes

1962 ◽  
Vol 84 (4) ◽  
pp. 365-371 ◽  
Author(s):  
H. S. Swenson ◽  
J. R. Carver ◽  
G. Szoeke
Keyword(s):  
Heat Transfer ◽  
Nucleate Boiling ◽  
Steel Tube ◽  
Heat Fluxes ◽  
Inside Surface ◽  
Film Boiling ◽  
Stainless Steel Tube ◽  
Transfer Coefficients ◽  
Steam Quality ◽  
Heat Transfer Coefficients

In large, subcritical pressure, once-through power boilers heat is transferred to steam and water mixtures ranging in steam quality from zero per cent at the bottom of the furnace to 100 per cent at the top. In order to provide design information for this type of boiler, heat-transfer coefficients for forced convection film boiling were determined for water at 3000 psia flowing upward in a vertical stainless-steel tube, AISI Type 304, having an inside diameter of 0.408 inches and a heated length of 6 feet. Heat fluxes ranged between 90,000 and 180,000 Btu/hr-sq ft and were obtained by electrical resistance heating of the tube. The operation of the experimental equipment was controlled so that nucleate boiling, transition boiling, and stable film boiling occurred simultaneously in different zones of the tube. The film boiling data were correlated with a modified form of the equation Nu = a a(Re)m(Pr)n using steam properties evaluated at inside surface temperature. Results of a second series of heat-transfer tests with tubes having a helical rib on the inside surface showed that nucleate boiling could be maintained to much higher steam qualities with that type of tube than with a smooth-bore tube.

Production Process and Heat Transfer Performance of 10/316 Clad Tube

2014 ◽  
Vol 1081 ◽  
pp. 270-274
Author(s):  
Zui Xian Yu ◽  
Xue Sheng Wang ◽  
Qin Zhu Chen
Keyword(s):  
Heat Transfer ◽  
Stainless Steel ◽  
Heat Transfer Coefficient ◽  
Carbon Steel ◽  
Transfer Coefficient ◽  
Heat Transfer Performance ◽  
Steel Tube ◽  
Stainless Steel Tube ◽  
Transfer Performance ◽  
Clad Tube

A new preparation technique of carbon steel/stainless steel clad tube was introduced, and the contact surface was well combined. Meanwhile, with the using of tube heat exchanger, the experiment on the heat transfer performance of the clad tube was done. Comparing the 10/316 clad tube and the 316 stainless steel tube, the effects on the heat transfer performance of 316 stainless steel tube attached to carbon steel was evaluated. It is showed that overall heat transfer coefficient of 10/316 clad tubes is higher than that of stainless steel tube. The average heat transfer coefficient of 10/316 clad tubes is about 18.7%~34.4% higher than that of stainless steel tube. Experimental investigation indicates that, by brazing and cold drawing, the 10/316 clad tube was well combined and the thermal conductivity was better than that of stainless steel tube.

Leak tightness of magnetic pulse crimped joints

2012 ◽  
Vol 3 (3) ◽  
pp. 243-250
Author(s):  
A. Loosveld ◽  
W. De Waele ◽  
K. Faes ◽  
O. Zaitov
Keyword(s):  
Stainless Steel ◽  
Steel Tube ◽  
Test Series ◽  
Stainless Steel Tube ◽  
Magnetic Pulse ◽  
Test Procedures ◽  
Burst Test ◽  
Master Thesis ◽  
Leak Tightness ◽  
Sealing Materials

The goal of this master thesis is to realize and investigate leak tightness of joints produced by theelectromagnetic pulse (EMP) crimping process. This way of joining metals has gained more attention lately.With EMP welding, leak tight joints can already be achieved. However, the crimping process has somemajor advantages over EMP welding like the fact that more material combinations are possible and itrequires less energy. To realize the leak tightness, two kinds of sealing materials are used: O-rings andadhesives. The workpieces consist of an aluminium or stainless steel tube which is crimped on a solidaluminium mandrel with circumferential grooves in it. First, some preliminary tests are performed todetermine how much the tubes deform in the grooves. This deformation mainly depends on the appliedcharging voltage and the geometry of the groove. With this information, it is possible to estimate the amountof compression an O-ring would undergo when placed inside this groove. On other workpieces, adhesiveswill be applied. Several test procedures can be conducted on the parts to investigate leak tightness. Theresults of a helium test and a pressure burst test on the first test series conducted at the Walloon researchcentre CEWAC already showed that the use of O-rings can be effective.

Biofouling Monitors for Noncylindrical OTEC Heat Exchanger Tubes

1982 ◽  
Vol 104 (3) ◽  
pp. 257-261
Author(s):  
T. M. Kuzay ◽  
C. B. Panchal ◽  
A. P. Gavin
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Steel Tube ◽  
Stainless Steel Tube ◽  
Thermal Energy Conversion ◽  
Shell And Tube ◽  
Ocean Thermal Energy ◽  
Analytical Approaches

Heat-transfer monitors (HTMs) have been used since 1976 to measure the reduction in the seawater heat-transfer coefficient due to buildup of biofouling and corrosion products inside circular tubes of shell-and-tube heat exchangers being developed for ocean thermal energy conversion (OTEC) plants. For OTEC heat exchangers (HXs) with other tube geometries, special, modified HTMs, which we call STMs, are being sought. The analytical approaches and calibration results to date are summarized for STMs of two types: (i) an STM simulating a rectangular seawater passage in a compact, aluminum, plate-fin HX, and (ii) an STM for a helical stainless-steel tube. The development of type 1 has been successful. A software change is needed for type 2.

Springback law of high-strength 21-6-9 stainless steel tube in numerical control bending under different process parameters

2015 ◽  
Vol 231 (10) ◽  
pp. 1783-1792 ◽  
Author(s):  
Jun Fang ◽  
Shiqiang Lu ◽  
Kelu Wang ◽  
Zhengjun Yao
Keyword(s):  
Stainless Steel ◽  
Friction Coefficient ◽  
Cross Section ◽  
Process Parameters ◽  
High Strength ◽  
Steel Tube ◽  
Numerical Control ◽  
Stainless Steel Tube ◽  
Outer Diameter ◽  
The Cross

In order to achieve the precision bending deformation, the effects of process parameters on springback behaviors should be clarified preliminarily. Taking the 21-6-9 high-strength stainless steel tube of 15.88 mm × 0.84 mm (outer diameter × wall thickness) as the objective, the multi-parameter sensitivity analysis and three-dimensional finite element numerical simulation are conducted to address the effects of process parameters on the springback behaviors in 21-6-9 high-strength stainless steel tube numerical control bending. The results show that (1) springback increases with the increasing of the clearance between tube and mandrel Cm, the friction coefficient between tube and mandrel fm, the friction coefficient between tube and bending die fb, or with the decreasing of the mandrel extension length e, while the springback first increases and then remains unchanged with the increasing of the clearance between tube and bending die Cb. (2) The sensitivity of springback radius to process parameters is larger than that of springback angle. And the sensitivity of springback to process parameters from high to low are e, Cb, Cm, fb and fm. (3) The variation rules of the cross section deformation after springback with different Cm, Cb, fm, fb and e are similar to that before springback. But under same process parameters, the relative difference of the most measurement section is more than 20% and some even more than 70% before and after springback, and a platform deforming characteristics of the cross section deformation is shown after springback.

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