Reverse Osmosis Desalination with Suspension Crystallization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Reverse osmosis desalination plants face challenges in low water recovery rates and high volumes of concentrated saline solution byproducts, which are environmentally harmful and costly to dispose of, with existing methods being energy-intensive, prone to scaling, and requiring large infrastructures.
Innovation Solution
A process involving a reverse osmosis membrane desalination plant followed by suspension and static crystallization units to further concentrate and reduce the volume of the saline solution byproducts, achieving a significant reduction in waste volume without high energy consumption or large infrastructure needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If reverse osmosis membrane desalination is used to produce fresh water, then fresh water can be obtained, but large volumes of concentrated saline solution byproduct are generated that are environmentally harmful and costly to dispose of
Solution Approach 1:
The patent changes the temperature parameter of the concentrated saline solution byproduct, cooling it to sub-zero temperatures to induce freezing. This phase change separates water (as ice) from salts (remaining in liquid brine), thereby reducing the volume of harmful saline solution that needs to be disposed of while recovering fresh water in the process
Solution Approach 2:
The patent utilizes the phase transition of water from liquid to solid (freezing) at sub-zero temperatures. By cooling the concentrated saline solution below its freezing point, water crystallizes as ice while salts remain dissolved in the remaining liquid, enabling separation and volume reduction of the harmful byproduct stream
2Quantity of substance
If thermally-based concentration methods are used to reduce byproduct volume, then the volume of concentrated saline solution can be reduced, but high energy consumption is required making the process costly
Solution Approach 1:
The patent replaces thermal-based concentration methods with a freezing-based separation process. Instead of using heat to evaporate water and concentrate brine (which consumes high energy), the system uses cooling to freeze water, allowing separation through phase change and filtration, thereby significantly reducing energy consumption while achieving the same volume reduction goal
3Use of energy by moving object
If solar ponds are used for concentration, then low energy costs are achieved, but large amounts of land and direct sunlight are required with low productivity
Solution Approach 1:
The patent transitions from solar pond evaporation (surface-area-dependent, outdoor process) to a controlled freezing process that can operate in three-dimensional vessels indoors or in controlled environments. This dimensional shift eliminates dependence on land area and sunlight, enabling high productivity through intensified cooling processes and continuous operation regardless of weather conditions
4Productivity
If pressure is increased to recover additional fresh water in reverse osmosis, then fresh water recovery is improved, but the water recovery rate tends to be low and disposal costs increase
Solution Approach 1:
The patent converts the harmful concentrated saline solution byproduct into a valuable resource by freezing it to recover fresh water. The concentrated brine that would otherwise be waste is cooled to sub-zero temperatures, causing water to freeze and be separated, thereby transforming an environmental liability into a source of additional fresh water recovery without requiring additional high-pressure RO 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
The process effectively reduces the volume of concentrated saline solution waste by over 80% and produces a second product water stream of drinking water quality, improving the desalination process's productivity and reducing the risk of scaling.
Implementation Method 1
Reverse osmosis (RO) is the most widespread technology for desalination of water... It is a membrane separation process in which water is recovered from a saline solution by pressurizing the solution beyond its osmotic pressure and essentially using the membrane to filter out the salt ions from the pressurized solution and allow only the water to pass
Implementation Method 2
the first byproduct stream is passed in a second desalination step through a suspension crystallization unit to form a second product water stream having a reduced salt concentration relative to that of the first byproduct stream and a second byproduct stream having an increased salt concentration relative to that of the first byproduct stream
Implementation Method 3
the second byproduct stream is passed in a third desalination step through either a static crystallization unit or the same or a second suspension crystallization unit to form a third product water stream having a reduced salt concentration relative to that of the second byproduct stream and a third byproduct stream having an increased salt concentration relative to that of the second byproduct stream
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A process for desalinating water is disclosed. The process comprises the steps of passing a feed stream of saline solution 2' in a first desalination step through a reverse osmosis membrane desalination plant 3' comprising at least one reverse osmosis desalination unit 4' to form a first product water stream 5' having a reduced salt concentration relative to that of the feed stream of saline solution 2' and a first byproduct stream 6' having an increased salt concentration relative to that of the feed stream of saline solution 2' characterized in that the first byproduct stream 6' is passed in a second desalination step through a suspension crystallization unit 7 to form a second product water stream 8 having a reduced salt concentration relative to that of the first byproduct stream 6' and a second byproduct stream 9 having an increased salt concentration relative to that of the first byproduct stream 6'. The invention further relates to an apparatus 1 for carrying out said process. The present invention further relates also to the use of the process or apparatus 1 for the reduction of the volume of the first byproduct stream of a reverse osmosis membrane desalination plant 3', preferably an in-land desalination plant 3', or in a device or plant or process for producing desalinated water, for salt production, for co-production of power and desalinated water, or for air conditioning.