Chelating Scale-Removal Composition for Mixed Sulfate Deposits
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Solution Overview
Problem
Existing methods for removing mixed sulfate scales, particularly barium sulfate, are inefficient, require high temperatures, and are costly, with mechanical removal causing significant downtime and chemical methods being limited in solubility and effectiveness, especially in offshore and regulated environments.
Innovation Solution
A composition comprising chelating agents like Li5DTPA, Na5DTPA, K5DTPA, Cs5DTPA, Na4EDTA, K4EDTA, TEAH4DTPA, TBAH5DTPA, carboxyl-containing fructans such as carboxymethyl inulin, and scale removal enhancers like potassium carbonate, is used to dissolve mixed sulfate scales at lower pH, allowing for efficient removal of barium sulfate into particles less than 1 micron in size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical means are used to remove sulfate scale, then scale removal is achieved, but equipment disassembly and reassembly are required causing significant downtime and cost
Solution Approach 1:
The patent replaces mechanical scale removal methods with a chemical dissolution system. The composition uses chelating agents (EDTA, DTPA), scale converters (sulfamic acid, oxalic acid), and surfactants to chemically dissolve sulfate scale in place, eliminating the need for mechanical disassembly and reassembly of equipment, thereby reducing downtime while maintaining effective scale removal
2Reliability
If existing chemical scale dissolvers are used, then some sulfate scale removal is achieved, but they require high temperatures and have limited solubility effectiveness
Solution Approach 1:
The patent modifies the chemical parameters of the dissolution system by using a combination of chelating agents (EDTA, DTPA) with scale converters (sulfamic acid, oxalic acid) and surfactants. This parameter change allows the system to achieve high solubility and dissolution capacity at lower temperatures compared to existing chemical dissolvers, improving effectiveness while reducing energy requirements
Solution Approach 2:
The patent creates a composite chemical system combining multiple functional components: chelating agents for metal ion complexation, scale converters for pH control and scale conversion, surfactants for wetting and emulsification, and buffering agents. This composite formulation synergistically enhances dissolution capacity and solubility at lower operating temperatures
3Reliability
If scale inhibitors are used to prevent scale formation, then scale prevention is achieved, but they are minimally effective and expensive
Solution Approach 1:
The patent enables the treatment system to be self-sufficient by incorporating scale converters that maintain optimal pH conditions and chelating agents that continuously bind metal ions, allowing the system to prevent and treat scale formation without requiring additional expensive inhibitor chemicals, thereby reducing chemical costs while maintaining prevention effectiveness
4Manufacturing precision
If existing sulfate dissolvers are used, then barium sulfate dissolution is limited, but they cannot effectively handle mixed sulfate scales or reduce particle size to less than 1 micron
Solution Approach 1:
The patent uses scale converters (sulfamic acid, oxalic acid) to adjust and maintain optimal pH parameters for maximum solubility of mixed sulfate scales. This parameter control, combined with chelating agents and surfactants, achieves both high solubility for mixed scales and effective particle size reduction to less than 1 micron, overcoming limitations of existing dissolvers
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 composition significantly enhances dissolution rates and capacity, reducing downtime and costs by enabling effective removal of mixed sulfate scales, including barium sulfate, at lower temperatures and pH levels, thus minimizing handling and disposal risks.
Implementation Method 1
providing a liquid composition comprising: a chelating agent selected from the group consisting of: Li5DTPA; Na5DTPA; K5DTPA; Cs5DTPA; Na4EDTA; K4EDTA; TEAH4DTPA; and TBAH5DTPA
Implementation Method 2
a carboxyl-containing fructan such as carboxymethyl inulin
Implementation Method 3
allowing for efficient removal of barium sulfate into particles less than 1 micron in size at lower pH
Data Source
Figure 1
AI summary
The present invention discloses a novel aqueous composition for use in removing mixed sulfate scale from a surface contaminated with such, said composition comprising: a chelating agent and a counterion component selected from the group consisting of: Li5DTPA; Na5DTPA; K5DTPA; Cs5DTPA; Na4EDTA; K4EDTA; TEAH4DTPA; and TBAH5DTPA; a dissolution enhancer; optionally a compound such as sodium gluconate or the like and a carboxyl-containing fructan such as carboxymethyl inulin. There is also disclosed methods to use such compositions.