Continuous Rod Corrosion Inhibitor Formulations for Environmental Cracking
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Solution Overview
Problem
Continuous rods in reciprocating pump systems are vulnerable to environmental cracking, particularly sulfide stress cracking, which is difficult to predict and conventional corrosion inhibitors are ineffective in mitigating this issue.
Innovation Solution
A synergistic formulation combining a base corrosion inhibitor with a sulfur compound modifier, such as cysteamine hydrochloride, is applied to the continuous rods to inhibit environmental cracking, including sulfide stress cracking, by minimizing wear and reducing failure rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional corrosion inhibitors are used, then ordinary ferrous metal corrosion is inhibited, but environmental cracking (sulfide stress cracking) is not prevented
Solution Approach 1:
The invention modifies the chemical composition parameters of corrosion inhibitors by incorporating sulfur-containing compounds (such as thiols, sulfides, or sultones) in specific concentrations (0.1-10,000 ppm) combined with traditional corrosion inhibitor classes (amines, imidazolines, carboxylic acids). This parameter change transforms the inhibitor's ability to protect against environmental cracking while maintaining corrosion inhibition capabilities.
Solution Approach 2:
The invention creates a composite corrosion inhibitor formulation that combines multiple chemical components: traditional corrosion inhibitors (amines, imidazolines, carboxylic acids, phosphates) with sulfur-containing compounds. This composite approach synergistically provides both corrosion inhibition and environmental cracking resistance, addressing the limitation of conventional single-function inhibitors.
2Strength
If high-strength metal alloys are used in continuous rods, then mechanical strength is improved, but susceptibility to environmental cracking increases
Solution Approach 1:
The sulfur-containing corrosion inhibitor acts as an intermediary substance between the high-strength metal alloy and the corrosive environment (H2S). It forms protective films on the metal surface that prevent direct interaction between the aggressive environment and the metal, thereby protecting high-strength alloys from environmental cracking while maintaining their mechanical strength properties.
Solution Approach 2:
The invention utilizes sulfur-containing compounds in the corrosion inhibitor formulation to counteract the harmful effects of hydrogen sulfide environment. By introducing controlled amounts of sulfur compounds (thiols, sulfides, sultones), the inhibitor transforms the harmful sulfur-containing environment into a beneficial protective mechanism that prevents environmental cracking of high-strength alloys.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The synergistic formulation effectively prevents environmental cracking, extending the lifespan of continuous rods and reducing downtime and costs associated with rod failures in hydrogen sulfide-containing environments.
Implementation Method 1
The sulfur compound modifier can be a thiol such as 2 mercaptoethanol, cysteamine, or a cysteamine salt
Data Source
AI summary
An environmental cracking inhibitor includes a base corrosion inhibitor and a sulfur compound modifier. The base corrosion inhibitor can be an imidazoline, an amine, a quaternary amine, a fatty acid derivative, a phosphate ester, or combinations thereof. The sulfur compound modifier can have the general formula HS—X, where X is a heteroatom substituted alkyl, cycloalkyl, aryl, and/or alkylaryl group. Suitable heteroatoms are sulfur, oxygen, phosphorus, nitrogen, and combinations thereof. The sulfur compound modifier can be 2 mercaptoethanol, cysteamine, or a cysteamine salt.