My Paper – Corrosion Inhibitor Study

THE EFFECTIVENESS OF POTASSIUM METAVANADATE AS A LOW-CARBON STEEL CORROSION INHIBITOR IN CHLORIDE – CARBONATE – AND SULFIDE – CONTAMINATED ENVIRONMENTS

 

ABSTRACT

 

 

Inhibitor addition is one of the common corrosion control methods. Potassium metavanadate (KVO₃) is commonly used as corrosion inhibitor in CO₂ absorber unit. Chloride and sulfide are common fluids in industry, and are also corrosive.

 

The objective of this research is to study the effectiveness of potassium metavanadate as a low-carbon steel corrosion inhibitor in the chloride, carbonate, or sulfide – contaminated environments. This objective was achieved by measuring low-carbon steel corrosion rate in different concentrations of contaminants. The corrosion rate was measured by Tafel method. The corrosion inhibition mechanisms were studied using cyclic voltammetry method. Meanwhile the corrosion products were identified by X – ray diffraction spectrometry (XRD).

 

This research results that KVO₃ is an effective corrosion inhibitor in chloride environment when the chloride concentration ranges between 20 g/L and 30 g/L. In this range of concentration, KVO₃ performs more than 99% efficiency. In sulfide environment KVO₃ is an ineffective corrosion inhibitor. While in carbonate environment whose concentration is below 150 g/L, the addition of KVO₃ gives no effect to the corrosion reaction. When carbonate concentration is above 150 g/L, it works as an ineffective corrosion inhibitor.

 

Keywords        : Potassium metavanadate, low – carbon steel, corrosion inhibitor

Another Prilling Session…

Finally my on-job training at PT Pupuk Kujang (Kujang Fertilizer) is done.. Well, that was an awesome experience and boring in the same way… Getting closer with the chemical processes there becomes a special experience, but I’m fed up with my field supervisor, whom – if only I could – I intend to kick out…

Hm… PT Pupuk Kujang built its first ammonia and urea plant in 1975. The first plant was then called Kujang I-A. It was the plant in which I had my on-job training. Since it was f

ounded many many years ago, it seems to be an old-fashioned plant. Computer monitor? You’ll find only one in each control room, for typing, not controlling. Computerized panel? you wish.. The panels in the control room are analog. There’s only one panel man, accompanied by one foreman. All the operators stand by on field.

The old-fashioned plant seems to be efficient no more. Well, leakage is everywhere. Ammonia release is everywhere. The plant has been operated over its lifetime. It was designed to operate for 20 years, so the corrosion allowance is only prepared for 20 years operation. That’s why, leakage everywhere…

Kujang has its new reactor in 2003. It was the second hand reactor from PUSRI (PT Pupuk Sriwijaya – Sriwijaya Fertilizer, Sumatera). Before installed, it was re-lined with stainless steel and completed with 12 trays. Thus it became a gas-liquid contactor in form of tray column. The former reactor was titanium-lined (Wow..!). It had no tray. With the new reactor, the conversion increased 3%.

The special thing in every urea plant is prilling tower. Yes, it is a 76 metres-high tower (see picture), in which top the melted urea is sprayed and -with the forced convection and other transport phenomena through the tower- become prilled urea when it reach the bottom of prilling tower. It’s really a high tower, and I’ve climbed it two times!! amazing…

With Prilling Tower as the background

Well, those two prilling sessions are unforgettable experiences… I was totally nervous when climbing it up. Enough, no more third prilling session… hahaha…

Me (rightmost) and Friends at PT Pupuk Kujang