Title:
Diffusion
Controlled Impingement Corrosion of some Metallic Fittings
Author : Mohamed Ahmed Fouad Mohamed
Collection : Ph.D. Chemistry
Abstract:
Impingement
corrosion of 90 copper elbow has been investigated in relation different
parameters. Rate of corrosion was expressed in terms of mass transfer
coefficient. The following conclusions Mass transfer coefficient increases as
solution velocity increases and decreases as rid increases. The dependence of
mass transfer coefficient on Sc varies according to the range of Sc considered.
Activation energy calculation reveals a value of 8.96 kCal /mol and 1l.5”
kCal/mol for low and high range of Sc respectively. Mass transfer data have
been these ocorrelated
using dimensionless analysis for different ranges of Sc. Dimensionless equations may be useful for the
90 copper elbow at different conditions. Flow inside 90 elbows enhances the
rate of mass transfer by a factor ranges from 1.65 to 26.2 relative to flow
inside straight tube which is a strong function of elbow diameter. Addition of
polyethylene oxide as drag- reducing polymer inhibits the impingement corrosion
rate in 90 copper elbow by 28% to 62% depending on operating conditions. The
presence of suspended solids in the solution increases the impingement corrosion
rate in 90 copper elbow by 3 to 13%. Scanning electron microscopy (SEM) study
on the corroded copper elbow show that maximum rate of corrosion occurred at
the stagnation point. Diffusion controlled impingement corrosion of 90°
stainless steel elbow depends to a great extent of surface passivity. Failure
analysis of 90 copper elbow shows that fracture started III the stretched
portion of the piping elbow wall. In the presence of two phase flow, the
increase of mass transfer coefficient depends on the gas velocity. Further
study in needed to study the effect of different elbow angles.
ليست هناك تعليقات:
إرسال تعليق