Statistical Aspects of CaCO3 Fouling in AISI 316 Stainless-Steel Tubes

1997 ◽  
Vol 119 (3) ◽  
pp. 581-588 ◽  
Author(s):  
S. M. Zubair ◽  
A. K. Sheikh ◽  
M. O. Budair ◽  
M. U. Haq ◽  
A. Quddus ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Cooling Water ◽  
Basic Mechanism ◽  
Experimental Program ◽  
Fouling Resistance ◽  
Steel Tubes ◽  
Experimental Apparatus ◽  
Hydraulic Conditions ◽  
Aisi 316 Stainless Steel ◽  
Aisi 316

Calcium carbonate fouling is typically encountered in a cooling-water circulating system. An experimental program is initiated to study fouling growth law (s) as well as the basic mechanism of calcium carbonate (CaCO3) scaling. After a brief description of the experimental apparatus and procedure for calculating fouling resistance, we present the deposition data in terms of fouling resistance as a function of time taken at different sections of the tube. In addition, the randomness of fouling growth is illustrated by repeating the experiments several times under the same thermal-hydraulic conditions. The results are presented in terms of a set of sample functions and their associated probability density functions at various levels of fouling. In addition, basic mechanism of CaCO3 scale formation is also explained through Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDX).

A parametric study of CaCO 3 scaling in AISI 316 stainless steel tubes

2001 ◽  
Vol 38 (1-2) ◽  
pp. 115-121 ◽  
Author(s):  
M. Sultan Khan ◽  
M. O. Budair ◽  
S. M. Zubair
Keyword(s):  
Stainless Steel ◽  
Parametric Study ◽  
Steel Tubes ◽  
316 Stainless Steel ◽  
Aisi 316 Stainless Steel ◽  
Aisi 316

Mitigation of Particulate Fouling by Ozonation

2003 ◽  
Vol 125 (1) ◽  
pp. 147-150 ◽  
Author(s):  
Bang-Yenn Wu ◽  
S. H. Chan
Keyword(s):  
Heat Transfer ◽  
Calcium Carbonate ◽  
Cooling Tower ◽  
Cooling Water ◽  
Reynolds Numbers ◽  
Fouling Resistance ◽  
Low Reynolds Numbers ◽  
Particulate Fouling ◽  
High Reynolds ◽  
Deposit Layer

Heat transfer surface fouling introduces a major uncertainty into the design and operation of cooling water systems. Fouling caused by calcium carbonate CaCO3 typically occurs on heat transfer surfaces. Ozone has been successfully used for more than 90 years as a disinfectant in drinking water. Recently, it has been proposed to use ozone for cooling tower water treatment. In this research, the effectiveness of mitigation of calcium carbonate particulate fouling by ozone was studied systematically. The experimental results show that, at low Reynolds numbers, though the ozonation retards the initial calcium carbonate particulate fouling rate, the retardation led to a non-porous deposit layer and a higher asymptotic fouling resistance. However, at high Reynolds numbers, ozonation was found to reduce the asymptotic fouling resistance.

Scaling of Heat Exchanger Tubes by Calcium Carbonate

1975 ◽  
Vol 97 (4) ◽  
pp. 504-508 ◽  
Author(s):  
A. P. Watkinson ◽  
O. Martinez
Keyword(s):  
Heat Exchanger ◽  
Calcium Carbonate ◽  
Mathematical Models ◽  
Flow Velocity ◽  
Test Section ◽  
Suspended Solids ◽  
Bulk Temperature ◽  
Fouling Resistance ◽  
Steam Temperature ◽  
Scaling Process

Scaling of copper heat exchanger tubes has been studied under conditions that promote rapid and severe scaling. Artificially hardened water of high dissolved and suspended solids is recirculated through a heated test section operated at constant steam temperature. The effects of flow velocity, tube diameter, and bulk temperature on the asymptotic fouling resistance have been determined. Results are interpreted in terms of mathematical models of the scaling process.

scholarly journals Breakdown and Evolution of the Protective Oxide Scales of AISI 304 and AISI 316 Stainless Steels under High-Temperature Oxidation

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
K. A. Habib ◽  
M. S. Damra ◽  
J. J. Saura ◽  
I. Cervera ◽  
J. Bellés
Keyword(s):  
Stainless Steel ◽  
Stainless Steels ◽  
Breakdown Point ◽  
304 Stainless Steel ◽  
Aisi 304 Stainless Steel ◽  
Protective Oxide ◽  
Aisi 304 ◽  
316 Stainless Steel ◽  
Aisi 316 Stainless Steel ◽  
Aisi 316

The failure of the protective oxide scales of AISI 304 and AISI 316 stainless steels has been studied and compared at 1,000°C in synthetic air. First, the isothermal thermogravimetric curves of both stainless steels were plotted to determine the time needed to reach the breakdown point. The different resistance of each stainless steel was interpreted on the basis of the nature of the crystalline phases formed, the morphology, and the surface structure as well as the cross-section structure of the oxidation products. The weight gain of AISI 304 stainless steel was about 8 times greater than that of AISI 316 stainless steel, and AISI 316 stainless steel reached the breakdown point about 40 times more slowly than AISI 304 stainless steel. In both stainless steels, reaching the breakdown point meant the loss of the protective oxide scale of Cr2O3, but whereas in AISI 304 stainless steel the Cr2O3scale totally disappeared and exclusively Fe2O3was formed, in AISI 316 stainless steel some Cr2O3persisted and Fe3O4was mainly formed, which means that AISI 316 stainless steel is more resistant to oxidation after the breakdown.

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