Eutectic Freeze Crystallization for Scale Control in Aqueous Solutions
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Solution Overview
Problem
Scale deposition in equipment during the recovery or production of crystallizable compounds from aqueous solutions leads to operational issues such as plugging, increased utility costs, and downgraded products due to clogging of reverse osmosis membranes.
Innovation Solution
The process involves eutectic freeze crystallization to reduce or prevent scale deposition by subjecting the aqueous solution to a eutectic freeze crystallization step, recycling the mother liquor, and treating it with seed crystals to precipitate scale-forming components, thereby maintaining their concentration below the precipitation level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reverse osmosis is used to produce purified water from aqueous solutions containing scale-forming components, then purified water is obtained, but the reverse osmosis membrane gets clogged by scale and becomes damaged
Solution Approach 1:
The patent applies preliminary action by performing eutectic freeze crystallization on the feed water before it enters the reverse osmosis membrane. This pre-treatment step removes scale-forming components (calcium, magnesium, barium salts) from the aqueous solution by freezing and crystallizing them, preventing these components from reaching and clogging the membrane during subsequent reverse osmosis operation
Solution Approach 2:
The patent extracts harmful scale-forming components from the aqueous solution through eutectic freeze crystallization. The process separates and removes calcium, magnesium, barium salts and other scale-inducing materials by forming ice crystals that exclude these impurities, which are then concentrated in the remaining liquid phase and can be easily removed
2Productivity
If conventional evaporation or crystallization methods are used to recover crystallizable compounds, then compounds can be recovered, but scale deposition occurs causing plugging and operational problems
Solution Approach 1:
The patent utilizes phase transitions by employing eutectic freeze crystallization instead of conventional thermal evaporation. The process involves freezing the aqueous solution to form ice crystals, which undergo phase transition from liquid to solid, while scale-forming components remain in the liquid phase or form separate crystalline structures. This phase change approach prevents scale deposition that typically occurs during evaporative concentration
Solution Approach 2:
The patent applies parameter changes by controlling temperature and concentration parameters during eutectic freeze crystallization. By maintaining specific temperature ranges and controlling the freezing process, the patent achieves selective crystallization of target compounds while keeping scale-forming components in solution or as separable precipitates, thereby preventing equipment plugging
3Duration of action of stationary object
If scale deposits accumulate in equipment, then production continues, but equipment must be taken out of production to remove scale causing downtime and increased costs
Solution Approach 1:
The patent prevents scale accumulation before it can cause operational problems by performing eutectic freeze crystallization as a pre-treatment step. This removes scale-forming components from the process stream upstream, eliminating the need for subsequent scale removal operations and maintaining continuous equipment operation
Solution Approach 2:
The patent converts the harmful effect of scale-forming components into a beneficial separation process. By utilizing eutectic freeze crystallization, the scale-forming components are selectively concentrated and recovered as valuable by-products or purified materials, while the main process stream remains free of scale deposits
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 efficiently removes scale-forming components, preventing membrane clogging and maintaining process efficiency, allowing for the recovery of valuable compounds like sodium chloride and sodium bicarbonate while reducing operational costs and downtime.
Implementation Method 1
subjecting the said solution to at least one eutectic freeze crystallization step with recovery of ice and said one or more crystallizable compounds in crystalline form
Implementation Method 2
subjecting the said recycle to a treatment with seed crystals for said scale forming or scale inducing compounds
Data Source
AI summary
The invention is directed to a process for the recovery or removal of one or more crystallizable compounds from an aqueous solution containing, apart from the said crystallizable compounds, one or more organic or inorganic scale-forming or scale-inducing materials having a lower solubility in water than the said crystallizable compounds, said process comprising subjecting the said solution to at least one eutectic freeze crystallization step with recovery of ice and said one or more crystallizable compounds in crystalline form, recycling at least part of the mother liquor formed in the said eutectic crystallization step and subjecting the said recycle to a treatment with seed crystals for said scale forming or scale inducing compounds, removing at least part of the solid material obtained in said treatment step and recycle of the aqueous liquid thus obtained to the eutectic freeze crystallization step or to the feed thereto.