TITLE:
Combating Corrosion in Transmission Pipelines in Marine Environment Using Vernomia Amydalina as Inhibitor
AUTHORS:
Samson Nitonye, Umoh Ofonime Emmanuel, A. Ogbonnaya Ezenwa
KEYWORDS:
Pipelines, Corrosion, Environment, Sea Water, Inhibitors, Specimen, VA Solution, Corrosion Rate (CR), Weight Loss (WL)
JOURNAL NAME:
Open Journal of Marine Science,
Vol.8 No.4,
October
26,
2018
ABSTRACT:
Pipelines are system of pipes designed to transport liquids, gases or solid/
liquid mixtures over long distances. Some are used for domestic, household
and sewage purposes. Others are buried underground or submerged in
water for transportation of natural oil and gas (O & G) products. In this
work, the specimens had to be kept in a workable state and steps were taken
to prepare each specimen: all cuts and sheared edges were ground out to prevent
them from becoming sites for preferential attack. The finishing of the
specimen surface with grit abrasive paper (sand paper) and rinsing of the
specimens in distilled water were done. Then degreasing of specimen in acetone
and air-dried were carried out. Upon drying, the specimens were immediately
weighed to obtain their initial weights. Twelve specimens were used
for the test as follows: 6 Aluminum (Al); and 6 mild steel (MS) samples. With
a 2 M concentration of Vernomia Amydalina (VA) extract solution, the MS
and Al samples were immersed in different plastic containers containing 400
ml of seawater with pH value of 7.25 with no (0%) inhibitor added to it. A 5%
(400 ml) of the VA solution was poured into the measuring cylinder for each
sample-Al and MS. The specimens were suspended by the strings and completely
immersed in the different percentage test media. The same procedure
was carried out for each of the different percentages, 10%, 15%, 20%, and
25% and a total of 12 solutions were set up. The experimental procedure used
was that seawater of 7.25 pH was obtained from Abonnema water front of
Rivers State. At the end of every week (168 hours), the specimens were removed
from the corrosive media. Observation and recording of appearance
of the specimen noting sites were done. Cleanings of specimen with white
handkerchief or tissue paper were carried out and washing of specimen with
distilled water, scrubbing of specimen with a soft brush and dipping the specimen into acetone after washing, it was removed to air-dry and weighed. It is
observed that optimum inhibition of coupons was obtained between 15% -
25% of VA solution during the first four weeks of testing. At the fifth week
the inhibitor was gradually losing its effectiveness. This means that more inhibitor
need be added at regular intervals to sustain the effectiveness of the
inhibitor.