MEG Reclamation via Seeded Calcium Carbonate Growth
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Solution Overview
Problem
Conventional methods for reclaiming monoethylene glycol (MEG) from contaminated streams are inefficient due to the difficulty in removing small-sized calcium carbonate particles, which can lead to equipment fouling and plugging, especially when saline formation water introduces salts that increase in concentration during regeneration cycles.
Innovation Solution
A method and apparatus that involves seeding the contaminated MEG stream with alkaline earth metal carbonate seeds to grow larger particles, which are then filtered out using a filtration unit, enhancing the separation efficiency and reducing the risk of fouling by increasing particle size from 2-5 microns to 10 microns or larger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional filtration methods are used to remove calcium carbonate particles from MEG stream, then the filtration process can be performed, but small particle size (2-5 microns) makes removal difficult and inefficient
Solution Approach 1:
The invention changes the particle size parameter from 2-5 microns to 10 microns or larger through a seeding process. Calcium carbonate seeds are added to the MEG stream, providing nucleation sites that promote growth of larger particles. This parameter change makes the particles sufficiently large for efficient filtration while maintaining effective salt removal.
Solution Approach 2:
The invention introduces calcium carbonate seeds as an intermediary substance that facilitates particle growth. These seeds act as nucleation sites that promote the formation of larger calcium carbonate particles from dissolved salts in the MEG stream, enabling subsequent efficient filtration.
2Quantity of substance
If MEG is regenerated by boiling off water, then water removal is achieved, but salt concentration increases until precipitation occurs causing fouling and plugging
Solution Approach 1:
The invention performs preliminary action by adding calcium carbonate seeds to the MEG stream before the regeneration process. This pre-seeding ensures that when water is removed and salt concentration increases during regeneration, the salts precipitate as large filterable particles rather than forming fouling deposits on equipment surfaces.
Solution Approach 2:
The invention converts the harmful effect of salt precipitation (which would cause fouling) into a beneficial outcome. By providing seeds for controlled precipitation, the salts form large particles that are easily filtered out, transforming what would be a harmful fouling mechanism into a useful particle formation process.
3Productivity
If centrifuges or DE filtration are used for salt removal, then salt removal is achieved, but the process requires long retention times (e.g., 10 hours)
Solution Approach 1:
The invention changes the particle size parameter to 10 microns or larger, which fundamentally alters the separation characteristics. This size change enables much faster filtration rates compared to conventional methods handling 2-5 micron particles, reducing the required retention time from 10 hours to a fraction of that time while maintaining effective salt 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 solution effectively removes salts and carbonates from the MEG stream, improving the efficiency of the reclamation process and reducing the risk of equipment fouling, allowing for the production of a relatively purified MEG stream with a concentration of CaCO3 particles reduced to 10 ppm or less.
Implementation Method 1
contacting an alkaline earth metal salt-contaminated MEG stream with an alkali metal carbonate and a base (accelerator) to form a mixture. The mixture may be contacted with recycled alkaline earth metal carbonate seeds to form a feed. The feed is routed to a seeding vessel for growing alkaline earth metal carbonate particles.
Implementation Method 2
A seeded effluent of relatively large particles is transmitted from the seeding vessel to a filtration unit. Alkaline earth metal carbonate solids are discharged from the filtration unit. A relatively reclaimed MEG stream is produced from the filtration unit.
Data Source
AI summary
The seeding of calcium carbonate into a calcium chloride-contaminated monoethylene glycol (MEG) stream accelerates the growth of calcium carbonate particles to a size that enhances their removal from the stream by filtration. A seeding vessel allows the calcium carbonate particles a time period to grow. Sodium carbonate may be added to the contaminated stream to facilitate calcium carbonate particle growth. A recycle seeding conduit may recycle seeds from a filtration unit to the seeding vessel. A base such as sodium hydroxide may be added to accelerate the precipitation process.