High-Pressure Nitrogen Distillation Without a Product Compressor
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Solution Overview
Problem
Existing nitrogen production under high pressure often requires additional energy loss and the use of a nitrogen compressor, which reduces the recovery ratio and increases manufacturing costs.
Innovation Solution
A process involving a high pressure distillation column and a medium pressure column, where oxygen-enriched liquid is reduced in pressure, expanded to produce power, and recycled to improve nitrogen recovery, eliminating the need for a nitrogen compressor by optimizing the system's thermal equilibrium and refrigeration balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a nitrogen compressor is added to meet customer demand for high-pressure nitrogen, then the nitrogen production capacity is improved, but the manufacturing cost and device complexity increase
Solution Approach 1:
The patent divides the distillation system into two separate columns: a first distillation column operating at high pressure and a second distillation column operating at medium pressure. This segmentation allows each column to be optimized for its specific pressure range, with the high-pressure column producing high-pressure nitrogen directly without requiring an additional compressor, thereby maintaining productivity while reducing device complexity
Solution Approach 2:
The patent introduces a pressure dimension differentiation by operating the two distillation columns at different pressure levels (high pressure vs. medium pressure). This dimensional change enables the system to produce high-pressure nitrogen directly from the high-pressure column, eliminating the need for post-compression and reducing overall device complexity
2Stress or pressure
If the top condenser pressure is increased to supply high pressure nitrogen, then the nitrogen production pressure is improved, but the recovery ratio and specific power deteriorate
Solution Approach 1:
By segmenting the distillation system into high-pressure and medium-pressure columns, the patent allows the high-pressure column to operate at the required nitrogen production pressure (5-10 bars or higher) while the medium-pressure column handles the oxygen-enriched liquid at lower pressure. This segmentation maintains energy efficiency by avoiding excessive condenser pressure increases that would worsen specific power consumption
3Device complexity
If the vaporized oxygen enriched liquid is expanded in a valve instead of an expander, then the device complexity is reduced, but energy is lost
Solution Approach 1:
The patent implements a self-service energy recovery system where the vaporized oxygen-enriched liquid from the high-pressure column is expanded through an expander that generates power. This generated power is then used to drive the cold compressor that compresses the waste vapor stream, creating a self-sufficient energy loop that reduces external power requirements and eliminates energy loss
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 process enhances nitrogen recovery ratio at higher pressures, reducing energy loss and manufacturing costs, allowing for efficient production of high-pressure nitrogen without additional compressors.
Implementation Method 1
cooling feed air to substantially the dew-point thereof
Implementation Method 2
cooling feed air to substantially the dew-point thereof
Implementation Method 3
reducing the pressure of said oxygen enriched liquid to a medium pressure
Implementation Method 4
reducing the pressure of said oxygen enriched liquid to a medium pressure
Implementation Method 5
heating said waste vapor stream
Implementation Method 6
expanding at least part of the heated waste vapor stream to produce power
Implementation Method 7
compressing a vapor stream removed from the medium pressure column in a cold compressor
Implementation Method 8
pumping said withdrawn liquid to said high pressure and injecting it at the top of the high pressure column
Data Source
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AI summary
A process for producing high pressure gaseous nitrogen, comprising : cooling feed air to substantially the dew-point thereof, introducing at least a portion of said air at a base of a high pressure column (107, 207); removing a oxygen enriched liquid from the base of said high pressure column; reducing the pressure of said oxygen enriched liquid to a medium pressure, wherein said medium pressure is between said high pressure and atmospheric pressure, introducing said oxygen enriched liquid at an intermediate place of a medium pressure column (106, 206); reducing the pressure of at least a part of a liquid removed from the base of said medium pressure column to a low pressure to cool a top condenser of said medium pressure column and to form a waste vapor stream; compressing a vapor stream removed from the medium pressure column in a cold compressor (105, 205), cooling said compressed vapor stream, and introducing it into the base of the high pressure column; heating said waste vapor stream, and expanding at least part of the heated waste vapor stream to produce power; withdrawing liquid from the top of said medium pressure column, pumping said withdrawn liquid to said high pressure and injecting it at the top of the high pressure column; and withdrawing product gaseous nitrogen from the top of the high pressure column.