Integrated Water-Nitrogen Tower for CO₂ and Air Separation Cooling
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Solution Overview
Problem
Current methods for separating carbon dioxide and other gases, as well as air through cryogenic distillation, often require separate cooling systems and risk contamination of air separation devices with CO2, leading to inefficiencies and potential blockages.
Innovation Solution
An integrated apparatus and method that uses a water-nitrogen tower to produce chilled water for both carbon dioxide and air separation devices, with the CO2-depleted gas being introduced at a lower level than nitrogen to prevent contamination, and optionally employs a mechanical refrigeration unit for additional cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate cooling system is used for each device, then each device can be cooled independently, but investment costs increase and system complexity increases
Solution Approach 1:
The patent merges the cooling functions for the CO2 separation device and air separation device into a single integrated water-nitrogen tower system. The tower receives hot water from both devices and cools them simultaneously using nitrogen gas, eliminating the need for separate cooling systems while reducing overall system complexity and investment costs.
Solution Approach 2:
The water-nitrogen tower is designed as a universal cooling system that can handle thermal loads from multiple different devices (CO2 separation and air separation). The system uses nitrogen gas as a universal cooling medium that can effectively cool both types of equipment through direct contact heat exchange.
2Productivity
If CO2-depleted gas is used to cool water in the tower, then cooling efficiency improves, but risk of CO2 contamination in the air separation device increases
Solution Approach 1:
The patent applies local quality by introducing CO2-depleted gas at a specific lower level in the water-nitrogen tower, below the nitrogen injection point. This creates a stratified flow pattern where the lighter nitrogen rises and protects the upper regions from CO2 contamination, while the CO2-depleted gas cools the water effectively in the lower regions where contamination risk is minimal.
Solution Approach 2:
Nitrogen gas acts as an intermediary protective layer in the tower. By introducing nitrogen above the CO2-depleted gas, it creates a physical barrier that prevents CO2 from rising into the air separation device while still allowing the CO2-depleted gas to perform its cooling function in the lower portion of the tower.
3Temperature
If nitrogen is expanded through a turbine to provide cooling, then sufficient cold is produced, but device complexity increases due to the need for a turbine
Solution Approach 1:
The patent uses pneumatic principles by introducing pressurized nitrogen gas directly into the water-nitrogen tower for cooling. The nitrogen provides cooling capacity through direct contact heat exchange with the hot water, eliminating the need for mechanical expansion devices like turbines while maintaining effective cooling performance.
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 reduces investment costs by integrating cold water production between devices with a single cooled water pipe, avoiding the need for a pressurized nitrogen line and minimizing the risk of CO2 contamination, while providing efficient cooling for both separation processes.
Implementation Method 1
cool water by heat exchange and evaporation with cold nitrogen from the air separation device
Implementation Method 2
cool water by heat exchange and evaporation with cold nitrogen from the air separation device
Implementation Method 3
separating air by cryogenic distillation
Implementation Method 4
the pressure prevailing in the supply pipe of the tower is lower for the line incondensables than for the nitrogen line
Data Source
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AI summary
An integrated apparatus for separating a mixture of carbon dioxide and at least one other gas and for separating air by air distillation comprises a unit (CPU) for separating a gaseous mixture comprising carbon dioxide and at least one other gas in order to produce a carbon dioxide-enriched gas and a carbon dioxide depleted gas and an air separation unit (ASU) for separating air by cryogenic distillation in order to produce at least one nitrogen-enriched gas stream (17), a water cooling tower that operates by direct contact and also a line for sending water to the top of the tower, a line for sending at least one portion of the nitrogen-enriched gas stream to a lower level of the tower, a cooled water line (15) for withdrawing cooled water from the tower and means for cooling the air (1) upstream of the air separation unit, the cooled water line being connected to means for cooling the air upstream of the air separation unit and to the inlet and/or to the outlet of the unit for separating the gaseous mixture.