Cascade Distillation Column Bypass for Pump-Free Liquid Return
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional cascade distillation processes for isotope enrichment require high pressures, large numbers of distillation columns, and the use of liquid pumps, leading to increased liquid hold-up, long startup times, and inefficiencies in cryogenic distillation due to heat leak and separation factor limitations.
Innovation Solution
A distillation apparatus with a cascade configuration that includes a bypass line connecting the liquid-return line and gas line, allowing evaporated gas to flow directly into the gas line, reducing liquid hold-up and ensuring a stable liquid head pressure for efficient liquid return to previous columns without rotary machines, and using vacuum insulation or cooling fluids to maintain liquid storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If liquid pumps are used to flow liquid between distillation columns, then liquid can be transported, but liquid hold-up increases and startup time becomes long
Solution Approach 1:
The patent replaces mechanical liquid pumps with a pressure difference-based liquid transport system. By controlling pressure differences between adjacent distillation columns, liquid flows automatically from high-pressure columns to low-pressure columns without mechanical pumping, eliminating liquid hold-up in pumps and reducing startup time while maintaining liquid transport capability.
Solution Approach 2:
The patent changes the pressure parameters between distillation columns to enable liquid flow. By creating controlled pressure gradients (higher pressure in feed-side columns, lower pressure in product-side columns), liquid is driven through the system based on pressure differences rather than mechanical pumping, resolving the contradiction between transport capability and startup time.
2Ease of operation
If liquid pumps are used in cryogenic distillation, then liquid can be pumped, but heat inleak increases
Solution Approach 1:
The patent eliminates mechanical liquid pumps from the cryogenic distillation system and replaces them with pressure-driven liquid flow. This substitution removes the heat inleak associated with pump motors and mechanical components, reducing energy loss while maintaining the ability to transport liquid between columns through controlled pressure gradients.
3Ease of operation
If high pressure is used toward the last column to enable pressure difference flow, then liquid can flow to previous columns, but separation factor becomes small
Solution Approach 1:
The patent optimizes the pressure parameter distribution across distillation columns. Instead of uniformly high pressure, it implements a gradient where pressure is higher in columns handling feed material and lower in columns handling enriched product. This pressure gradient enables liquid flow while maintaining favorable separation factors in the enrichment section by operating at lower pressures where relative volatility is higher.
4Manufacturing precision
If a large number of distillation columns are connected in cascade, then enrichment can be achieved, but apparatus complexity increases
Solution Approach 1:
The patent divides the enrichment process into multiple staged distillation columns connected in cascade, where each column performs a portion of the separation. This segmentation allows the overall enrichment task to be achieved through multiple smaller separation steps, each operating at optimized conditions, rather than requiring a single excessively complex column.
Solution Approach 2:
The patent varies operating parameters (pressure, temperature, liquid-to-vapor ratio) across the cascade of distillation columns. By adjusting these parameters in each column according to its position in the cascade and the enrichment requirements, the system achieves high enrichment capability while optimizing the number and configuration of columns needed.
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 configuration stabilizes the distillation process, reduces operational costs, and improves productivity by ensuring efficient liquid return and minimizing heat leak, thus enhancing the separation efficiency and reducing startup time in isotope enrichment.
Implementation Method 1
gas-feeding line which feeds gas from the distillation column to a latter distillation column by using pressure difference between the distillation columns
Implementation Method 2
a condenser and a reboiler attached to each of the distillation columns
Implementation Method 3
a condenser and a reboiler attached to each of the distillation columns
Implementation Method 4
using vacuum insulation or cooling fluids to maintain liquid storage
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A distillation apparatus of the present invention includes a distillation column group in which a plurality of distillation columns comprising a condenser and a reboiler is connected in the form of a cascade; a gas-feeding line (11) which feeds gas from the distillation column to a latter distillation column (12); a gas line (13) which introduces the gas from the distillation column (12) to the condenser (14) attached to the distillation column (12); a liquid-line which withdraws a condensed liquid from the condenser (14); a liquid-reflux line (18) which introduces a part of the condensed liquid from the liquid-line to the distillation column (12); a liquid-return line (17) which returns the remainder of the condensed liquid from the liquid-line to a former distillation column; a valve (19) provided on the liquid-return line; and a bypass line (20) which connects the liquid-return line and the gas line (13) so as to flow an evaporated gas generated in the liquid-return line (17) to the gas line (13).