MEG Divalent Ion Removal via Chemical Precipitation and Membrane Separation
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Solution Overview
Problem
Conventional methods for removing divalent ions from monoethylene glycol (MEG) feed streams in the oil and gas industry are inefficient, leading to equipment clogging, high MEG loss, and increased costs due to aeration, chemical usage, and space requirements, making them unsuitable for offshore applications.
Innovation Solution
A system and process involving chemical reaction to form insoluble carbonate and hydroxide salts, followed by membrane-type solid-liquid separation, which recycles MEG and facilitates disposal of waste as solid, reducing equipment downtime and operational costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional precipitation methods are used to remove divalent ions, then salt removal is achieved, but MEG loss increases due to high solubility of some salts
Solution Approach 1:
The invention changes the chemical parameters by adding specific chemicals (sodium hydroxide, sodium carbonate, calcium hydroxide) to alter the solubility characteristics of divalent ion salts, transforming them from highly soluble forms that cannot be removed by precipitation into insoluble forms that can be effectively separated, thereby preventing MEG loss while achieving salt removal
2Reliability
If disk stack centrifuges are used for salt removal, then precipitation separation is achieved, but oxygen absorption increases due to aeration
Solution Approach 1:
The invention replaces the mechanical centrifugal separation system with a chemical precipitation system followed by simple filtration or settling, eliminating the need for high-speed rotation and aeration that occurs in disk stack centrifuges, thereby preventing oxygen absorption while achieving salt removal
3Reliability
If filter presses are used for salt removal, then solid-liquid separation is achieved, but device complexity and space requirements increase
Solution Approach 1:
The invention uses disposable or easily replaceable filter media such as filter paper or cloth in simple filtration setups, replacing complex and expensive filter press equipment, thereby reducing device complexity and space requirements while achieving effective salt removal through chemical precipitation followed by simple filtration
4Reliability
If candle filters are used for salt removal, then filtration is achieved, but operating costs increase due to chemical and gas requirements
Solution Approach 1:
The invention extracts and removes the need for pre-coat chemicals and body-aid chemicals by using simple filtration media, and eliminates the requirement for large volumes of gas for drying the filter cake, thereby reducing operating costs while maintaining effective salt removal through chemical precipitation and simple filtration
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 process effectively removes divalent ions, minimizes MEG loss, and facilitates efficient disposal of waste as solid, improving the efficiency and cost-effectiveness of MEG reclamation or regeneration while being compact and suitable for offshore use.
Implementation Method 1
chemical reaction to form insoluble carbonate and hydroxide salts
Implementation Method 2
membrane-type solid-liquid separation
Data Source
AI summary
A system and process for removing divalent ions from a MEG feed stream (15) is presented. The system includes a chemical treatment tank (25) where chemicals are mixed with the feed stream (15) to form insoluble carbonate and hydroxide salts. The system also includes a membrane-type solid-liquid separation unit (60) that receives the feed stream (35) from the chemical treatment tank (25) and separates it into a filtrate (90) containing MEG and a retentate (130) containing the insoluble salts. The system may also include washing the retentate (130) to remove additional MEG, which is then recycled to a MEG regeneration or reclamation process. The system may also include a dryer (140) that receives waste slurry (132) from the solid-liquid separation unit (60) and dries it to form a solid waste, thereby facilitating its handling, storage, and disposal.