Inhibitive action of sodium nitrite sodum hexametaphosphate inhibitor blend

مقدم أطروحة جامعية

Muhammad, Raghad Yasin

الجامعة

الجامعة التكنولوجية

الكلية

-

القسم الأكاديمي

قسم الهندسة الكيمياوية

دولة الجامعة

العراق

الدرجة العلمية

ماجستير

تاريخ الدرجة العلمية

2006

الملخص الإنجليزي

The purpose of this investigation is to study the electrochemical behavior of carbon steel, in naturally aerated water used in cooling tower of Al-Dura Refinery.

The performance of sodium nitrite (SN) and sodium hexametaphosphate (SUMP) inhibitor blend for inhibition of such corrosion process have been investigated under turbulent flow conditions.

To achieve such control, a rotating cylinder electrode system was used to provide quantified hydrodynamic mass transfer conditions.

Potentiostatic polarization measurements were carried out on line with computer by an interface.

The potential and the current were obtained automatically from the computer.

The experiments were carried out with water at 303, 313 and 323 K and rotational speed ofO, 100, 200, 300 and 400 r.p.m.

Similar experiments were carried out using the formulated inhibitor blend, i.e., SN: SHMP = (500:100) p.m.

Conventional weight loss tests were used to calculate the corrosion rate in both uninhibited and inhibited neutral and alkaline solutions, pH (7, 7.5,8, 8.5,9,10,11 and, 12).

The effect of pH evidenced the following two regions: (I) in nearly neutral solution, moderately low corrosion rates were obtained that was the corrosion rates decreased with increasing of pH, while at pH 9, the corrosion rate was enhanced; slight precipitate of some calcium phosphate was observed, thus the best observed pH range for this inhibitor blend may be considered as between (8-8.5), And (2) in alkaline solution, low corrosion rates were noted.

Moreover, it was noted that increasing the velocity at constant temperature will increase the rate of uninhibited corrosion.

But using the inhibitors will reduce the rate of corrosion at all ph.

The corrosion rate increases with increasing temperature with and without inhibitor.

In general, in the presence of inhibitor, lower current densities were observed for both regions (the anodic and catholic).

Such behavior gives indication that SN / SHMP mixtures act as a mixed type inhibitor which forms a barrier layer on the metal surface from corrosion products such as, iron oxide, iron phosphate and calcium phosphate.

التخصصات الرئيسية

الهندسة الكيميائية

الموضوعات

• درجات الحرارة

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-305553