MEG Calcium Removal via Salt-Saturated Slipstream Concentration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current MEG reclamation processes face challenges in effectively removing calcium from rich MEG streams, especially when initial designs do not include a calcium removal step, leading to equipment plugging and inefficiencies due to low calcium concentrations and space constraints, particularly in offshore locations.
Innovation Solution
The process involves increasing the calcium concentration in the MEG feed stream by removing a salt-saturated slipstream and mixing it with fresh water or MEG, then routing it to a precipitator, where sodium carbonate is added to enhance calcium carbonate formation, allowing for higher temperature processing and reduced equipment size, thereby promoting larger crystal formation and faster reaction rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If calcium removal is performed using conventional processes with low calcium concentration feed streams, then the process can operate with existing equipment, but the reaction rate is slow and residence time is insufficient for effective crystal formation
Solution Approach 1:
The patent concentrates calcium ions in the feed stream to approximately 10,000 ppm before introducing to the precipitator, compared to conventional processes that treat dilute streams. This parameter change in calcium concentration accelerates the precipitation reaction rate and enables effective crystal formation within the available residence time, resolving the contradiction between removal efficiency and time availability.
2Reliability
If a calcium removal step is added to processes not originally designed for it, then calcium can be effectively removed, but additional specialized equipment and space are required
Solution Approach 1:
The patent adapts existing flash separator equipment to serve dual purposes: its vapor outlet continues MEG/water separation while its liquid outlet becomes the feed source for the calcium removal precipitator. This multi-functional use of existing equipment enables calcium removal without requiring completely new specialized equipment, reducing device complexity while maintaining process reliability.
Solution Approach 2:
The patent combines the calcium removal function with the existing flash separator system by using its liquid outlet as the precipitator feed source and integrating the concentrated calcium stream treatment into the existing process flow. This merging approach enables effective calcium removal while utilizing existing equipment infrastructure.
3Reliability
If calcium concentration is kept low in the flash separator, then equipment plugging is prevented, but calcium removal efficiency is reduced
Solution Approach 1:
The patent segments the calcium handling into two distinct stages: (1) a concentrator unit that accumulates calcium ions from multiple feed streams to high concentrations, and (2) a precipitator unit that receives only the concentrated stream for efficient calcium carbonate formation. This segmentation allows the flash separator to maintain low calcium levels (preventing plugging) while the precipitator achieves high removal efficiency through concentrated processing.
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
This approach effectively removes calcium more efficiently, reduces MEG losses, and minimizes equipment size requirements, enabling effective calcium removal without additional specialized equipment, while maintaining calcium concentrations below plugging levels and preventing carbon dioxide release.
Implementation Method 1
the calcium in the rich MEG will be reacted with sodium carbonate (soda ash) to form insoluble calcium carbonate and soluble sodium chloride. The insoluble calcium carbonate precipitates and is removed as solid crystals.
Implementation Method 2
the increasing step increases the calcium concentration to about 25,000 ppm
Implementation Method 3
The soluble sodium chloride remains in solution and is separated from the rich MEG by flashing the rich MEG under vacuum and at temperature.
Implementation Method 4
The vaporized water and MEG are then separated by partial condensation in what is commonly termed a 'distillation' tower.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A MEG reclamation process includes the step of increasing above 2,000 ppm the divalent metal salts concentration of a rich (wet) MEG feed stream flowing into a precipitator. The increasing step includes routing a salts-saturated MEG slipstream from the flash separator it to the precipitator. The slipstream may be mixed with a fresh water feed stream, a portion of the rich MEG feed stream, or some combination of the two. The rich MEG feed stream also may be split into two streams, with a portion of the stream being heated and routed to the flash separator and the other portion being combined as above with the removed slipstream. The process can be performed on the slipstream after dilution and prior to entering the precipitator or after being loaded into the precipitator. Removal of the insoluble salts may be done in either a batch or continuous mode.