Oil-Soluble Molybdenum Complexes for Naphthenic Acid Corrosion
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Solution Overview
Problem
High temperature corrosion in petroleum refining processes, particularly due to naphthenic acids and reactive sulfur species, is challenging, and existing solutions often require expensive alloys or phosphorus-containing inhibitors that impair catalyst function.
Innovation Solution
The use of sulfur-containing molybdenum complexes, such as Mo2—(S—R)n, where R represents oxygen, nitrogen, or carbon-containing compounds, to inhibit corrosion by forming a protective coating on metal surfaces in contact with high-temperature hydrocarbon fluids, reducing the need for phosphorus-based inhibitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phosphorus-containing corrosion inhibitors are used to inhibit high temperature corrosion, then corrosion inhibition effectiveness is improved, but catalyst function is impaired
Solution Approach 1:
The patent extracts and removes phosphorus from the corrosion inhibitor composition, using sulfur-containing molybdenum complexes instead. This eliminates the harmful effect of phosphorus on catalysts while maintaining corrosion protection through alternative chemistry (molybdenum-sulfur complexes that form protective films without phosphorus contamination).
Solution Approach 2:
The patent introduces sulfur-containing ligands as intermediary compounds that mediate between the molybdenum center and the metal surface. These sulfur-containing organic compounds (such as dithiocarbamates, dithiophosphates without phosphorus, or other sulfur-based ligands) form the bridge that enables corrosion protection through film formation while avoiding direct phosphorus-catalyst interactions.
2Reliability
If expensive alloy materials are used to address corrosion, then corrosion resistance is improved, but operating costs increase
Solution Approach 1:
The patent employs inexpensive sulfur-containing organic ligands and molybdenum complexes that can be added in small amounts to the fluid stream. These corrosion inhibitors act as sacrificial protective agents, forming disposable protective films on metal surfaces that prevent corrosion without requiring expensive alloy replacements. The inhibitors are consumed over time but are much cheaper than alloy materials.
Solution Approach 2:
The patent changes the chemical composition parameters of the corrosion protection system by using sulfur-containing organic compounds with specific ligand structures (such as dithiocarbamates, xanthates, or other sulfur-based ligands) coordinated to molybdenum. This chemical parameter change enables effective corrosion inhibition at low concentrations, avoiding the need for expensive metallurgical solutions.
3Reliability
If metallurgical materials advances are used to address corrosion, then corrosion protection is improved, but material costs increase
Solution Approach 1:
The patent uses low-cost sulfur-containing organic compounds and molybdenum complexes as corrosion inhibitors that can be continuously added to the system. These inexpensive chemical inhibitors form protective films that prevent corrosion, serving as a cost-effective alternative to expensive corrosion-resistant alloy materials.
Solution Approach 2:
The patent introduces sulfur-containing organic ligands as intermediary compounds that mediate corrosion protection by forming protective complexes with molybdenum and depositing on metal surfaces. These organic intermediaries (such as dithiocarbamates, xanthates, or other sulfur-based ligands) provide corrosion protection through chemical film formation rather than relying on expensive metallurgical materials.
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 sulfur-containing molybdenum complexes provide effective corrosion inhibition, extending catalyst life and reducing operational costs by forming a protective layer that minimizes corrosion in metal containments at temperatures up to 600°C.
Implementation Method 1
forming a protective coating on metal surfaces in contact with high-temperature hydrocarbon fluids
Data Source
AI summary
Disclosed are sulfur-containing molybdenum complexes used in compositions and methods for inhibiting or reducing high temperature corrosion in petroleum refineries.