Tritiated Water Separation via Heavy Water Gas Hydrate Crystallization
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Solution Overview
Problem
Current methods are not industrially feasible for separating tritiated water from light water due to low concentration and small density difference, making existing separation techniques impractical for industrial-scale processing.
Innovation Solution
A two-stage method involving the addition of heavy water to contaminated water to form gas hydrates, followed by separation and recrystallization to isolate tritiated water, utilizing differences in crystallization temperatures and pressures to maintain heavy water in a liquid state while converting tritiated water into a gas hydrate for separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If gas hydrate crystallization is used to separate tritiated water from light water, then separation based on crystallization temperature difference is achieved, but the extremely low concentration of tritiated water prevents critical nucleus formation
Solution Approach 1:
Heavy water serves as an intermediary substance that facilitates the crystallization of trace tritiated water. By adding heavy water to the contaminated light water, the system enables gas hydrate formation at higher temperatures than pure tritiated water would require, allowing critical nucleus formation even at extremely low concentrations (1.11 to 9.29×10^-8 g/L). The heavy water molecules act as templates that promote the ordering of water molecules into the gas hydrate crystal structure.
Solution Approach 2:
The invention changes the temperature parameter to enable separation. By controlling the temperature to be above the gas hydrate formation temperature of pure tritiated water but below that of light water, and utilizing the presence of heavy water, the system achieves selective crystallization. The temperature is specifically maintained in the range where heavy water and tritiated water form gas hydrates while light water remains liquid.
2Ease of manufacture
If gravity-based separation is used for gas hydrate and liquid phase, then simple separation process is achieved, but the very small density difference between tritiated water and light water prevents sufficient separation
Solution Approach 1:
The invention exploits phase transition differences to achieve separation. By controlling temperature and pressure conditions, tritiated water (in the presence of heavy water) transitions to a solid gas hydrate phase while light water remains in the liquid phase. This phase transition creates a fundamental physical difference that enables efficient separation, overcoming the limitation of small density differences in the liquid phase.
3Manufacturing precision
If centrifugal method is used for separation, then separation force is increased, but high-speed and long-term operation is demanded making it impractical
Solution Approach 1:
The invention uses phase transition to create solid gas hydrate crystals that can be easily separated from liquid phase through simple filtration or decantation. This eliminates the need for high-speed centrifugal separation, allowing for continuous, high-rate processing without the mechanical constraints of centrifugal equipment.
4Manufacturing precision
If conventional treatment methods are used, then most radioactive nuclear species are removed, but tritium remains at concentrations above regulated levels
Solution Approach 1:
Heavy water acts as a mediator that enables selective crystallization of tritiated water through gas hydrate formation. The addition of heavy water creates a system where tritiated water molecules are incorporated into the gas hydrate crystal structure in the presence of heavy water, allowing separation from light water that remains in the liquid phase. This mediator approach achieves the high separation purity needed to reduce tritium to environmentally allowable levels.
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 method allows for the industrial-scale separation of tritiated water, achieving concentrations below environmentally allowable limits and processing rates exceeding 400 m3/day, enabling the use of separated tritium in advanced nuclear reactors.
Implementation Method 1
converting the liquid mixture of the contaminated water and the heavy water into a mixture of the light water and a gas hydrate consisting essentially of both the tritiated water and the heavy water as the crystal structure under a condition of converting both the heavy water and the tritiated water into the gas hydrate
Implementation Method 2
utilizing the difference in the crystallization temperatures of the gas hydrates between heavy water and light water
Implementation Method 3
separating the gas hydrate from the light water; utilizing the difference in their specific densities, for separation of liquid phase and gas hydrate crystal
Implementation Method 4
breaking the gas hydrate structure consisting essentially of both the tritiated water and the heavy water in the crystal structure
Data Source
AI summary
Provided is an industrially feasible method for separating tritiated water from contaminated water. The method for separating tritiated water from light water contaminated by the tritiated water, includes the steps of; adding heavy water to the contaminated water; converting the liquid mixture of the contaminated water and the heavy water into a mixture of the light water and a gas hydrate consisting essentially of the tritiated water and the heavy water as the crystal structure under a condition of converting into the gas hydrate of at least one of the heavy water and the tritiated water, and yet keeping most of the light water in liquid state; and separating the gas hydrate from the light water.