Cryogenic CO/N2 Distillation With Reboiler-Assisted Phase Separation
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Solution Overview
Problem
In industrial processes for producing carbon monoxide and hydrogen, existing methods face challenges in efficiently separating nitrogen and carbon monoxide, particularly when the nitrogen content is not compatible with the desired purity of the CO product, leading to energy inefficiencies and the need for additional separation steps.
Innovation Solution
A process and apparatus involving a distillation column with a reboiler and heat exchanger system that cools and partially condenses the feed gas, allowing for the separation of nitrogen and carbon monoxide, with energy-efficient reboiling and compression to achieve a product enriched in carbon monoxide, and optional integration with phase separators for enhanced separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a CO/N2 separation column is added to the cold box, then the CO purity is improved, but the device complexity and energy consumption increase
Solution Approach 1:
The patent combines the CO/N2 separation column with the existing cold box unit, integrating the separation functionality into the already-present cryogenic system. This merging approach allows the separation column to utilize the cold box's cooling infrastructure, reducing the need for duplicate equipment and minimizing overall system complexity while achieving the required CO purity.
Solution Approach 2:
The patent employs phase transition of carbon monoxide within the separation column to achieve nitrogen removal. By controlling temperature and pressure conditions, CO transitions between liquid and vapor phases, enabling selective separation from nitrogen based on their different phase behavior and volatility characteristics, thus achieving high purity CO without requiring overly complex equipment.
2Manufacturing precision
If the nitrogen content in natural gas is high, then the CO purity without separation column is maintained, but additional separation steps are required
Solution Approach 1:
The patent implements preliminary cooling and partial condensation of the synthesis gas before it enters the separation column. This preliminary action prepares the gas mixture by condensing heavier components and adjusting the phase distribution, which facilitates more efficient separation in the subsequent column and reduces the number of additional separation steps needed to achieve the desired CO purity.
Solution Approach 2:
The patent utilizes changes in temperature and pressure parameters throughout the separation process. By carefully controlling these parameters in different sections of the cold box and separation column, the system optimizes the separation efficiency between CO and nitrogen, enabling effective purification while maintaining productive operation without excessive separation stages.
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 compressor energy consumption by approximately 15% and enables effective separation of nitrogen and carbon monoxide, addressing energy inefficiencies and purity issues in CO production.
Implementation Method 1
the feed gas is cooled in a heat exchanger
Implementation Method 2
at least part of a gas derived from the feed gas is sent to a bottom reboiler of the distillation column in order to condense it at least partially by producing a liquid and possibly a gas
Implementation Method 3
a distillation column in which: the feed gas is cooled in a heat exchanger
Implementation Method 4
the liquid from the first phase separator is expanded
Implementation Method 5
at least part of the liquid from the second is vaporized to divert the gas to be sent to the reboiler
Data Source
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AI summary
In a method for separating a feed gas, containing nitrogen and carbon monoxide as main components, in a distillation column (15): the feed gas is cooled in a heat exchanger (3); at least a portion of the feed gas, or at least a portion of a gas derived from the feed gas, is sent to a reboiler (5) of the distillation column so as to condense the gas while producing a liquid, and optionally a gas; at least a portion of the liquid is sent to the column; a nitrogen gas-rich flow is extracted from the column; a carbon monoxide-rich flow is extracted from the column, heated in the heat exchanger, and compressed so as to provide a carbon monoxide-rich material at production pressure; the feed gas is sent, after cooling, into a first phase separator (51); the liquid is released from the first phase separator (51); the released liquid is sent into a second phase separator; and at least a portion of the liquid from the second phase separator is vaporized so as to obtain the gas to be sent to the tank reboiler.