11
Corrosion Monitoring
It is essential for operators of industrial process plants to have aprogram for
controlling corrosion. For suchaprogram to be effective, it should facilitate
safe operation of the process unit over its intended life and maximize
the economic return to the owner.Toaccomplish these objectives, acorrosion
control program should consider: characteristics (toxicity,flammability, etc.)
of the process; selection of construction materials; control of operating
conditions; addition of neutralizing or inhibition chemicals; and monitoring
to ensure that anticipated results are obtained.
Selection of construction materials almost alwaysinvolves acompromise
betweene xpensive and often hard-to-obtain alloys highly resistant to
corrosion by the process undera ny conceivable operating conditions and
less expensive, more available materials that are more susceptible to
corrosion. Often, am aterial can have acceptabler esistance to ap rocess at
design conditions but corrode at veryh ighr ates during process upsets.
Particularly in these cases, on-line monitoring and control of process
operating parametersa nd direct on-line monitoring of corrosionr ates are
essential to an effective program. Several types of materials are oftenused in
conjunction in the construction of process facilities. For instance, corrosionresistanta lloysa re used in particularlys usceptible equipment( heat
exchanger tubes, for example) with less expensive materials used elsewhere
in the process. It is, of course, essentialthat the behavior of various metals in
the anticipated operating environment be known in advanceo fs election.
whereas thereisavast array of available literature on the subject, laboratory
and fieldtrialsare oftenperformed to verify theoretical predictions or tryout
new materials before acommitment is made to use them in the process unit.
Sometimes al ess expensive material, that would otherwise be unacceptable because of low corrosion resistance can still be the best choice when
used in conjunction with ac hemical corrosion inhibitor injection system or
an anodic or cathodic protection system.
There are many operating and environmental parameterst hat can affect
the corrosiono fametal—changes in any that can greatly accelerate the
corrosion rate. Without early detection and accurate measurement of the
impact of thesechanges, costly and potentially hazardous damage can occur
CAT8247—CHAPTER 11—6/10/2006—12:55—SRIDHAR—XML MODEL B–pp. 533–547
533
Corrosion Monitoring
It is essential for operators of industrial process plants to have aprogram for
controlling corrosion. For suchaprogram to be effective, it should facilitate
safe operation of the process unit over its intended life and maximize
the economic return to the owner.Toaccomplish these objectives, acorrosion
control program should consider: characteristics (toxicity,flammability, etc.)
of the process; selection of construction materials; control of operating
conditions; addition of neutralizing or inhibition chemicals; and monitoring
to ensure that anticipated results are obtained.
Selection of construction materials almost alwaysinvolves acompromise
betweene xpensive and often hard-to-obtain alloys highly resistant to
corrosion by the process undera ny conceivable operating conditions and
less expensive, more available materials that are more susceptible to
corrosion. Often, am aterial can have acceptabler esistance to ap rocess at
design conditions but corrode at veryh ighr ates during process upsets.
Particularly in these cases, on-line monitoring and control of process
operating parametersa nd direct on-line monitoring of corrosionr ates are
essential to an effective program. Several types of materials are oftenused in
conjunction in the construction of process facilities. For instance, corrosionresistanta lloysa re used in particularlys usceptible equipment( heat
exchanger tubes, for example) with less expensive materials used elsewhere
in the process. It is, of course, essentialthat the behavior of various metals in
the anticipated operating environment be known in advanceo fs election.
whereas thereisavast array of available literature on the subject, laboratory
and fieldtrialsare oftenperformed to verify theoretical predictions or tryout
new materials before acommitment is made to use them in the process unit.
Sometimes al ess expensive material, that would otherwise be unacceptable because of low corrosion resistance can still be the best choice when
used in conjunction with ac hemical corrosion inhibitor injection system or
an anodic or cathodic protection system.
There are many operating and environmental parameterst hat can affect
the corrosiono fametal—changes in any that can greatly accelerate the
corrosion rate. Without early detection and accurate measurement of the
impact of thesechanges, costly and potentially hazardous damage can occur
CAT8247—CHAPTER 11—6/10/2006—12:55—SRIDHAR—XML MODEL B–pp. 533–547
533