Liquid Nitrogen Turbine Power Generation Without Gas Recompression
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Solution Overview
Problem
Existing steam-powered power plants have inefficiencies in converting thermal energy into mechanical work due to the limitations of closed-loop systems, where waste heat is released, and the high costs associated with compressing nitrogen as a working fluid exceed the efficiency gains.
Innovation Solution
The use of liquid nitrogen from an air separation unit, pressurized to at least 1.8 atmospheres, is introduced into a turbine to generate power, where it is heated and expanded, with the expanded nitrogen vented to ambient air, avoiding the inefficiencies of recompressing gaseous nitrogen and reducing water usage by 25-30%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nitrogen is compressed to be used as working fluid in turbine, then power generation efficiency improves, but compression costs increase
Solution Approach 1:
The patent changes the phase parameter of nitrogen from gas to liquid, enabling efficient pressurization through pumping rather than compression. Liquid nitrogen is pumped to 1.8-3.0 atmospheres and then vaporized in the turbine, avoiding the high energy costs of compressing gaseous nitrogen while maintaining high power generation efficiency
Solution Approach 2:
The air separation unit pre-cools and liquefies atmospheric nitrogen before it enters the power generation system. This preliminary liquefaction action eliminates the need for subsequent gas compression, as liquid nitrogen can be efficiently pressurized by pumps and directly fed to the turbine after vaporization
2Power
If steam is used as working fluid, then heat conversion to mechanical work is achieved, but waste heat loss increases
Solution Approach 1:
The patent uses nitrogen, an inert gas, as the working fluid instead of steam. Nitrogen does not condense at ambient temperatures, eliminating the condensation step that causes significant waste heat loss in steam cycles. The nitrogen expands in the turbine and is directly vented or recirculated without requiring cooling towers, dramatically reducing thermal energy waste
3Reliability
If cooling tower is used for condensation, then steam cycle operation is maintained, but water consumption increases
Solution Approach 1:
The patent extracts and eliminates the cooling tower condensation step from the power generation cycle by using nitrogen instead of steam. Since nitrogen remains gaseous throughout the expansion process and does not require condensation, the entire water-intensive cooling infrastructure is removed, reducing water consumption by 25-30%
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 significantly improves energy conversion efficiency, reducing water consumption and operational costs, while allowing for energy storage to smooth out power demand fluctuations, achieving approximately three times the efficiency of steam turbines.
Implementation Method 1
The liquid nitrogen is pumped to a pressure of at least 1.8 atmospheres and expanded in a turbine to generate power
Implementation Method 2
The pressurized nitrogen-rich stream is heated for expansion in a nitrogen driven turbine. The pressurized nitrogen-rich stream can be heated using a furnace (e.g., a coal burner) and the thermal energy is converted to work in the turbine
Implementation Method 3
the pressurized nitrogen-rich stream is heated for expansion in a nitrogen driven turbine
Implementation Method 4
The nitrogen is vented to the ambient air instead of recompressing the nitrogen due to the inefficiencies associated with compressing gaseous nitrogen
Data Source
AI summary
An air separation unit is integrated with a power generating plant to improve the efficiency of power generation. The methods and systems improve the efficiency of power generation by utilizing liquid nitrogen from the air separation unit as the working fluid in a turbine. The liquid nitrogen is pressurized while in the liquid state. After warming the pressurized nitrogen stream by cooling the air for the air separator unit, the compressed nitrogen is expanded in a turbine to perform work. After expansion, the nitrogen is vented to ambient air. The nitrogen in its pressurized state can be used for energy storage and/or for smoothing out power demand on a power grid.