Packed column
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Solution Overview
Problem
Packed columns in cryogenic air separation units experience deteriorated distillation performance due to liquid maldistribution, especially at high pressures, despite the use of intermediate liquid distributors, leading to increased power consumption and apparatus costs when compensating measures like increasing gas-liquid contactor height or feed air are taken.
Innovation Solution
A packed column design with a total height ratio of gas-liquid contactors above the highest gas disperser set to 0.5 or greater, incorporating at least one intermediate liquid distributor, and optionally integrating a gas disperser with the distributor to uniformly disperse ascending gas and liquid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If intermediate liquid distributors are placed at regular intervals to prevent liquid maldistribution, then liquid distribution uniformity is improved, but device complexity increases
Solution Approach 1:
The invention extracts the liquid distribution function from separate intermediate liquid distributors and integrates it into the gas-liquid contactor structure itself. The packing material is designed to inherently provide both gas-liquid contact surface and liquid redistribution functionality, eliminating the need for additional intermediate distributor components while maintaining liquid distribution uniformity.
Solution Approach 2:
The invention merges the functions of gas-liquid contact and liquid distribution into a single integrated structure. The packing material serves dual purposes: providing surface area for mass transfer and automatically redistributing liquid to prevent maldistribution, thereby simplifying the overall device structure.
2Reliability
If the height of gas-liquid contactors is increased to compensate for performance deterioration, then distillation performance is improved, but apparatus size increases
Solution Approach 1:
The invention applies local quality enhancement by designing packing material with specific localized characteristics that optimize both mass transfer efficiency and liquid distribution. The packing structure incorporates features at specific locations and scales that improve overall performance without requiring increased height, allowing compact design with high distillation efficiency.
3Reliability
If feed air amount is increased to maintain distillation performance, then separation efficiency is improved, but power consumption increases
Solution Approach 1:
The invention changes the physical parameters of the packing material, including surface area, porosity, and structural geometry, to optimize mass transfer characteristics. These parameter modifications enable efficient separation at lower feed air flow rates, reducing the energy required by compressors and other auxiliary equipment while maintaining high separation efficiency.
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 design suppresses distillation efficiency and gas-liquid contact efficiency losses, reducing the need for taller contactors and lower feed amounts, thereby maintaining performance without increasing apparatus size or power consumption.
Implementation Method 1
uniformly disperse ascending gas and liquid flow
Implementation Method 2
distributes descending liquid again
Implementation Method 3
distillation operations inside the column
Implementation Method 4
gas-liquid contact efficiency
Implementation Method 5
cooled to -165°C, which is near the dew point, by a main heat exchanger
Implementation Method 6
lowered in pressure to 300 kPaG by a liquid-air pressure reducing valve 117, so that the temperature drops to -180°C due to the Joule-Thomson effect
Implementation Method 7
the nitrogen gas is liquefied and the whole low-temperature liquid air is vaporized into low-temperature air
Implementation Method 8
the low-temperature air is expanded to 30 kPaG and its temperature is lowered to -170°C by adiabatic expansion
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
Provided is a packed column capable of achieving sufficiently high distillation performance even with the height of its gas-liquid contactors reduced. The packed column is a packed column which includes a gas-liquid contactor 17, 18 inside a tubular body 16 and a liquid distributor 19 in the upper most portion and causes descending liquid and ascending gas to contact each other in the gas-liquid contactor. The operation pressure is in the range of 200 to 1500 kPaG. The relative volatility is in the range of 1.9 to 3.1. The gas-liquid contactor is vertically divided into at least two parts to thereby form a plurality of gas-liquid contactors. A gas disperser 20 is provided at at least one position between a lower one of the gas-liquid contactors and an upper one of the gas-liquid contactors, the gas disperser uniformly dispersing the composition of the ascending gas rising from the lower gas-liquid contactor toward the upper gas-liquid contactor.