Chelating Agent Recycling Through pH-Controlled Metal Ion Separation
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Solution Overview
Problem
Existing methods for recycling chelating agents used in oil and gas treatment fluids are costly, require complex equipment, and can damage the agents, reducing their effectiveness for reuse.
Innovation Solution
A method involving pH adjustments and scale inhibitors to release and precipitate metal ions, allowing for the recycling of chelating agents without substantial metal ion precipitation, maintaining their effectiveness for subsequent use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electrolysis is used to de-chelate chelating agents, then the chelating agents can be recycled, but the process is costly, requires large-footprint equipment, and damages the chelating agent molecules
Solution Approach 1:
The patent applies parameter changes by adjusting pH levels to control the de-chelation process. By changing the pH parameter, the method enables selective release of metal ions from chelating agent complexes without requiring complex electrolysis equipment, thus simplifying the recycling process while maintaining chelating agent integrity
Solution Approach 2:
The patent replaces the mechanical/electrical electrolysis system with a chemical pH-based approach. Instead of using electrical current to de-chelate agents, the method uses chemical pH adjustments to achieve the same separation effect, eliminating the need for large-footprint electrolysis equipment
2Productivity
If electrolysis is used to de-chelate chelating agents, then the chelating agents can be recycled, but the chelating agent molecules are damaged, reducing their effectiveness
Solution Approach 1:
The patent uses controlled pH parameter changes to achieve gentle de-chelation that preserves chelating agent molecule integrity. By carefully controlling pH levels and using selective precipitation, the method avoids the damaging effects of electrolysis while still achieving effective recycling and maintaining chelating agent effectiveness
3Productivity
If pH is adjusted to release metal ions from chelating agent complexes, then the chelating agents can be separated, but metal ion precipitation occurs
Solution Approach 1:
The patent applies sequential pH adjustments with specific targets (pH > 7 for initial release, then pH 7-4 for controlled precipitation). By precisely controlling pH parameters at different stages, the method achieves complete metal ion release followed by selective precipitation, enabling effective chelating agent separation while minimizing harmful metal ion precipitation
Solution Approach 2:
The patent extracts metal ions from chelating agent complexes through controlled pH changes, then selectively removes them through precipitation. This two-step extraction process separates the chelating agents from metal ions effectively, allowing the chelating agents to be recycled while managing metal ion removal
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 method allows for the effective recycling of chelating agents, maintaining their functionality and efficacy for reuse in subterranean and downstream operations, without the need for costly equipment or complex processes.
Implementation Method 1
adjusting the pH of the treatment fluid, if necessary, to a pH above about 7, wherein the pH is sufficient to release one or more metal ions from the one or more metal-chelating agent complexes
Implementation Method 2
precipitate one or more of the released metal ions from the treatment fluid to form one or more precipitated metal hydroxides
Implementation Method 3
lowering the pH of the treatment fluid to a pH of below about 4, wherein the pH is sufficient to release any remaining metal ions from the one or more metal-chelating agent complexes
Implementation Method 4
precipitate the released chelating agents from the treatment fluid to form recycled chelating agents
Data Source
AI summary
Methods for processing treatment fluids comprising providing a treatment fluid comprising one or more metal-chelating agent complexes; adjusting the pH of the treatment fluid, if necessary, to a pH above about 7, wherein the pH is sufficient to release one or more metal ions from the one or more metal-chelating agent complexes and to precipitate one or more of the released metal ions from the treatment fluid to form one or more precipitated metal hydroxides; separating the precipitated metal hydroxides, if present, from the treatment fluid; lowering the pH of the treatment fluid to a pH of from about 7 to about 4 prior to, concurrently with, and/or after combining the treatment fluid with a scale inhibitor; and lowering the pH of the adjusted treatment fluid to a pH of below about 4. The recycled chelating agents may be used in subsequent subterranean formation operations or a subsequent downstream operations.