Nanofiltration Membrane System for Electrolytic Cell Scaling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Precipitation and scaling within or downstream of electrolytic cells used for producing chlorine or chlorine-produced oxidants from saline water, particularly seawater, negatively impact cell performance due to pH rise at the cathode during the electrolytic process.
Innovation Solution
A system and method involving pre-treatment of saline feed streams using an ultrafiltration or dual media filtration system followed by a nanofiltration sulfate removal membrane system to reduce scaling, specifically employing a NATCO sulfate removal membrane system to soften seawater before routing it to electrolytic cells, optionally de-aerating the stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If seawater is directly fed to electrolytic cells, then chlorine production occurs, but precipitation and scaling of calcium and magnesium salts negatively affects cell performance
Solution Approach 1:
The patent applies preliminary action by implementing pre-treatment steps before electrolysis. Specifically, seawater is treated with a nanofiltration membrane system to remove sulfate and divalent ions (calcium and magnesium) before the water enters the electrolytic cells. This preliminary removal of scaling-prone ions prevents precipitation during electrolysis, thereby maintaining cell performance while enabling continuous chlorine production.
2Reliability
If nanofiltration sulfate removal is implemented prior to electrolysis, then scaling is reduced, but system complexity increases
Solution Approach 1:
The patent employs porous materials in the form of nanofiltration membranes with specific pore structures and charge characteristics. These membranes selectively remove sulfate and divalent ions from seawater through size exclusion and electrostatic repulsion mechanisms. The use of specialized porous membrane materials achieves effective pre-treatment in a single compact unit, reducing overall system complexity compared to conventional multi-step pre-treatment approaches.
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 effectively reduces scaling and precipitation of calcium and magnesium salts within or downstream of electrolytic cells, enhancing cell performance and preventing membrane fouling, thereby maintaining efficient operation.
Implementation Method 1
pre-treating a saline feed stream with a nanofiltration system employing a sulfate removal membrane system
Implementation Method 2
The softened low sulfate seawater (permeate stream) produced in the nanofiltration sulfate removal membrane system
Implementation Method 3
electrolytic cells which are used to produce chlorine or chlorine-produced oxidants from saline water
Data Source
Figure 1A
Figure 1B
AI summary
A system to reduce scaling within or downstream of an electrolytic cell (30) includes sulfate removal membranes (20) located upstream of one or more electrolytic cells (30) which are arranged to receive a permeate feed stream (25) from the sulfate removal membranes (20). The membranes can be nanofiltration membranes. The saline feed stream (10), permeate feed stream (25), or both may be de-aerated streams. The electrolytic cells (30) may be part of an electro-chlorination unit and can be divided electrolytic cells.