CORROSION INHIBITION OF MILD STEEL USING MORINGA OLEIFERA AND AZADIRACHTA INDICA LEAVES AS EXTRACT

ABSTRACT

 

The Corrosion inhibition potential of Mild steel using Moringa Oleifera and Azadirachta Indica leaves as extracts in HCl environment at room temperature has been investigated. The study was carried out using the weight loss technique. The results obtained show Moringa Oleifera and Azadirachta Indica leaves extract as potential inhibitors of mild steel corrosion in HCL. An acidic environment was created to act as a catalyst enhancing the corrosion process. These experiments were all carried out under room temperature and atmospheric pressure. The results obtained showed that the inhibition efficiency of the extract increases with an increase in the concentration of the extract. The best optimum efficiency in both cases was obtained from 50ml concentration of Moringa Oleifera leave extract with inhibition efficiency of 81.04% and 50ml concentration of Azadirachta Indica leave extract with inhibition efficiency of 74.31%. This experimental condition ensured that the catalyst was the only driving force in the corrosion process. These results obtained here are largely consistent with other studies using plant extract that show that corrosion inhibition is highest (or most efficient) at the highest concentration of the extracts in solution. The maximum concentration where constant inhibition was not achieved even at 50ml concentration, perhaps that could exist at higher concentrations or for specific  temperature and pressure conditions .

CHAPTER ONE

 

• Introduction

1.1 Background of the Study

Corrosion has negative effects on the progress of science and technology with range of records of process failure and losses in the oil and gas sector, it’s simply the degradation of metallic materials due to interaction with its environment. Corrosion can also be referred as a universal phenomenon in the sense that it occurs in air, water, soil and in every environment, Other than material loss, corrosion interferes with human safety, disrupts industrial operations and poses danger to the environment. Nations of the world loose a considerable amount of their gross domestic product (GDP) as a result of corrosion, for example the United States and the United Kingdom loose about $70 billion annually, accounting for about 4% of their national GDP[1]. Country like Nigeria will most likely be spending a huge fortune in it industrial sector on corrosion control.

Four type of corrosion exist:  weight loss, stress corrosion cracking (SCC), corrosion fatigue, and galvanic corrosion[2]. The commonly known example of corrosion is the corrosion of iron. When unprotected steel is exposed to the environment or environmental elements, the surface begins to form a reddish-brown color this indicates that steel is corroding. Rust consists of hydrated iron (iii) oxide Fe₂O₃.nH₂O (where n represents the number of moles of water which varies) rust begins in faults or areas of impurity. In these areas iron (ii) ions are formed in solution the reaction is given as:

Fe(s) → Fe²⁺ (aq) + 2e⁻

This shows that iron undergoes an oxidation reaction, these areas where the oxidation takes place are known as the anodes. The ions move away from the anodic regions and react with hydroxide ions present in water and form iron (ii) hydroxide:

²⁺ ( ) + 2 ⁻ ( ) → ( )₂ ( )

A corrosion inhibitor refers to chemicals compounds that are added to a gas or liquid to reduce the rate of corrosion of a material. The efficiency of an inhibitor is dependent on the composition of the fluid, the amount of moisture[3].

There are several corrosion inhibitors use as first line of defense against corrosion, these inhibitors are categorized as anodic inhibitors, cathodic inhibitors, mixed inhibitors and volatile corrosion inhibitors (VCI)[4]. The usual mechanism of action is formation of a covering or coating on the metal surface, this prevents corroding materials from gaining access to the metal surface thereby preventing corrosion, these inhibitors can be mixed with solutions that are in direct interaction with the metal. They prevent or reduce the rate of the anodic or cathodic reactions in the electrochemical or corrosion cell that leads to corrosion of the metal surface. They do this by forming passive or invisible films over the surface. These films can also be insoluble and form over anodic or cathodic reaction sites. The selection of inhibitors to be used largely depends on the acid’s concentration, temperature, velocity of flow and or organic substances and the metallic area or material exposed to the acidic solution. The commonly used inhibitors in acidic media are mostly compounds of organic origins which contain sulfur, oxygen and nitrogen, plant extracts as cheap, affordable and environmental friendly source of corrosion inhibitors has been of great interest and its presently attracting lots of attention[5].

Over the last decade, commercial inhibitors have been manufactured and working effectively to impede corrosion of iron in sour system. Those products contain at least one of the subsequent surfactants: fatty (acids, amines, diamines, Amido-amines or imidazolines), (quaternary oxyalkylated) amines, other amine derivate, and oxygen, sulfur or phosphorus containing compounds which act as film forming inhibitors . The most efficient inhibitors used in the industry contain heteroatoms. For example, nitrogen, sulfur, and/or oxygen and also the hydrophobic hydrocarbon series in the structures create a decrease in corrosion rate of metals, although this has not been fully investigated yet over the past few decades. While many synthetic composites revealed good anticorrosive achievements, many of them were extremely toxic to both humans and the environment[6]. The study of plant extracts as low-cost and ecofriendly corrosion inhibitors is of great interest from an environmental perspective and is attracting a significant level of attention. Green corrosion inhibitors have a promising future for the quality of the environment because they do not contain heavy metals or other toxic compounds. In addition, they are biodegradable and renewable source of materials[5]. Acidic solutions have wide applications in the industry; the well-known fields of application are acid pickling, industrial acid cleaning and oil well oxidizing. Acids increase the rate of corrosion of metals as a result the drill of corrosion inhibition is usually employed in the reduction of the rate of corrosion of metals by acidic attack.

• Research Problem

Corrosion is an important and costly problem in the petroleum industry, requiring special considerations in the design of production equipment. Severe environments involving CO₂ or H₂S pose particular difficulties. This phenomenon must be addressed daily as far as there are increasing needs of metallic materials in all facets of technological development. Chemical inhibitors have been very effective in addressing this among other corrosion protection methods. In very recent time, however, there has been the need to look at some other environment friendly substances, especially from natural resources that could be used to control/prevent incessant corrosion problems apart from the synthesized inorganic and other organic chemicals, some of which are toxic to the environment[7].

• Motivation

Corrosion is a natural potential hazard associated with oil and gas production and transportation facilities. Almost any aqueous environment promotes corrosion, which occurs under numerous conditions in oil and gas production, processing and pipelines systems. Different industries have lost huge amount of money due to corrosion. Corrosion is usually considered a universal problem, with this research another solution will be provided to the industries and companies whom lose huge amount of time and amount due to corrosion.

 

 

 

 

 

 

 

 

 

1.4 Aim and Objectives of the Study

The aim of this research project is to control the corrosion process using natural extract of Moringa Oleifera and Azadirachta Indica leaves.

Objectives

• To Determine the corrosion of steel in HCL in the presence of different concentrations of moringa and neem leaves.
• To Determine the corrosion rate of steel in the presence and absence of Moringa Oleifera and Azadirachta Indica leaves.
• To Determine the weight loss of the steel
• To Determine the amount of the Moringa Oleifera and Azadirachta Indica leaves concentration needed to slow the corrosion rate of steel.

CORROSION INHIBITION OF MILD STEEL USING MORINGA OLEIFERA AND AZADIRACHTA INDICA LEAVES AS EXTRACT

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