Dry Ice Reactor Cooling Cycle for Easy Block Release
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Solution Overview
Problem
Existing methods for producing dry ice face issues such as high equipment costs, uneven heat transfer, and adhesion of dry ice to reactor surfaces, leading to inefficiencies and unreliable production of carbon dioxide pellets.
Innovation Solution
A method involving a reactor chamber where liquid carbon dioxide is cooled externally by a cold heat transfer fluid to below its freezing point, followed by a warm-up phase with a warmer heat transfer fluid to reduce adhesion and facilitate easy removal of the dry ice, ensuring uniform cooling and minimizing gas inclusions, while maintaining pressure above the triple point to prevent gas formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid carbon dioxide is cooled by thermal contact with a cold heat transfer fluid at a heat exchanger surface, then the carbon dioxide freezes into a body of dry ice, but the dry ice tends to stick to the reactor tubes, complicating removal
Solution Approach 1:
The patent applies periodic action by alternating between cooling phases (to freeze CO2) and heating phases (to warm the heat exchanger surface and reduce adhesion). This periodic temperature variation enables reliable dry ice production while facilitating easy removal by temporarily changing surface conditions.
Solution Approach 2:
The patent changes the temperature parameter of the heat exchanger surface dynamically - cooling it during the freezing phase and heating it during the removal phase. This parameter change reduces adhesion forces between dry ice and reactor tubes, solving the sticking problem while maintaining reliable production.
2Productivity
If the heat transfer fluid is continuously supplied to the heat exchanger surface, then cooling is maintained, but heat transfer becomes uneven, reducing production efficiency
Solution Approach 1:
The periodic supply and interruption of heat transfer fluid creates alternating cooling and warming phases. This periodic action ensures uniform cooling by allowing heat distribution to equalize during interruptions, while maintaining overall productivity through continuous cyclic operation.
3Ease of operation
If the heat exchanger surface is heated to warm-up phase, then dry ice detachment is facilitated, but additional energy is required for heating
Solution Approach 1:
The system uses the same heat transfer fluid circulation infrastructure for both cooling and heating phases. The fluid serves dual purposes - cooling during freezing and heating during detachment - reducing overall energy requirements compared to separate systems. The thermal energy required for heating is minimized by using the fluid's thermal capacity efficiently.
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 produces extremely hard, gas-free dry ice that is suitable for blasting applications, with improved detachment from reactor surfaces and consistent production, enhancing the efficiency and reliability of the process.
Implementation Method 1
cooled (cooling phase) to a temperature below its melting point by thermal contact with a cold heat transfer fluid at a heat exchanger surface
Implementation Method 2
frozen into a body of dry ice
Implementation Method 3
heat transfer fluid with a higher temperature than the surface temperature is introduced – this is referred to as the 'warm-up phase'. This warms the heat exchanger surface, reducing the adhesion between the dry ice and the inner surface of the reactor chamber
Data Source
AI summary
In a method for producing solid carbon dioxide particles, liquid carbon dioxide is supplied to a reactor chamber whose outer surface acts as a heat exchange surface for thermal contact with a heat transfer fluid. The carbon dioxide in the reactor chamber is brought to a temperature below the melting temperature and frozen to form a block of dry ice by uniformly cooling the heat exchanger surface with a correspondingly cold heat transfer fluid. After the carbon dioxide has been frozen, the heat exchanger surface is heated by means of appropriately heated heat transfer fluid and the pressure in the reactor chamber is reduced to ambient pressure. Due to the heating of the heat exchanger surface, the dry ice body is detached from the reactor chamber and the dry ice body can be easily removed from the reactor chamber. The dry ice produced with the method according to the invention and the device according to the invention has only few gas inclusions and is of high density, homogeneity and hardness.