Gas mixture separation method
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Solution Overview
Problem
Existing gas separation processes fail to achieve high purification due to difficulties in obtaining low temperatures in heat exchangers, leading to high dew points in depleted flows and limited component separation efficiency.
Innovation Solution
The process involves cooling a gas mixture, expanding it in a spun flow through a nozzle, heating and compressing the depleted flow, and using the enriched flow as a cooling agent, with additional cooling and expansion steps to enhance separation efficiency, including the use of centrifugal expanders or throttle valves, and incorporating the cooled gas into the fractionating column or as an ejector to optimize component separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the gas mixture is cooled in heat exchangers to enable component separation, then the separation efficiency improves, but the temperature cannot be sufficiently lowered due to component condensation in the heat exchangers
Solution Approach 1:
The cooling process is divided into multiple stages: first cooling in heat exchangers, then further cooling through expansion in a nozzle, and additional cooling of the depleted flow. This segmentation allows each stage to operate within optimal temperature ranges while achieving the overall low temperature needed for high separation efficiency.
Solution Approach 2:
The gas mixture is pre-cooled in heat exchangers before entering the nozzle for expansion. This preliminary cooling action prepares the mixture for the subsequent expansion process, enabling the system to achieve lower temperatures without causing condensation in the heat exchangers.
2Manufacturing precision
If the gas mixture is cooled to low temperatures to reduce dew point, then the purification degree improves, but the heat exchangers cannot achieve sufficiently low temperatures due to component condensation
Solution Approach 1:
The purification process is segmented into multiple cooling stages. The first stage uses heat exchangers for preliminary cooling, the second stage uses nozzle expansion for further cooling and separation, and the third stage cools the depleted flow separately. This segmentation enables achieving low dew points and high purification degrees without condensation issues in heat exchangers.
Solution Approach 2:
The nozzle acts as an intermediary device between the heat exchanger and the separation column. It enables further cooling of the gas mixture through expansion without requiring the heat exchanger to achieve extremely low temperatures, thus avoiding condensation while still achieving the required purification degree.
3Manufacturing precision
If additional cooling and expansion steps are added to enhance separation, then the purification degree improves, but the device complexity increases
Solution Approach 1:
The depleted flow is utilized multiple times in the system: it cools the incoming gas mixture in the heat exchanger, undergoes further expansion, and the cooled version is fed back to the column. This multi-functional use of the depleted flow enhances purification without requiring completely separate processing lines, thus limiting the increase in device complexity.
Solution Approach 2:
The depleted flow itself is used as a cooling agent for the incoming gas mixture. This self-service approach allows the system to achieve additional cooling and enhancement of separation without requiring external cooling resources, thereby improving purification degree while avoiding proportional increases in device complexity.
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 the purification degree of the outgoing gas by effectively managing temperature and flow dynamics, enabling a higher removal of targeted components such as carbon dioxide from the gas mixture.
Implementation Method 1
cooling the mixture
Implementation Method 2
expanding at least a part of the column overhead product in a spun flow in a nozzle, the flow being separated into a flow enriched with components heavier than methane and a flow depleted of said components
Implementation Method 3
heating the depleted flow at the expense of cooling the mixture
Implementation Method 4
compressing the heated depleted gas flow in a compressor
Implementation Method 5
the heated and compressed depleted gas flow is cooled in an air cooling apparatus
Implementation Method 6
the enriched flow or a part of the same is used as a cooling agent to cool the mixture
Data Source
Figure 1
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AI summary
The invention relates to a technique for processing associated or natural gas, more specifically to a process for the low-temperature separation of the components of a gas. The proposed invention is intended to achieve the technical result of increasing the degree of purification of the output gas. This technical result is achieved in that in the gas mixture separation method according to the invention, which includes cooling the mixture, expanding the products obtained therefrom, pumping at least a part of the products through a distillation column, expanding the mixture in a swirling flow in a nozzle with the division of the flow into a flow enriched with components heavier than methane and a flow depleted of such components, and heating the depleted flow by cooling the products obtained from the mixture, the heated gas flow is compressed in a compressor and cooled in an air cooling apparatus, part of the gas product obtained is used as output product, while the other part is further cooled and expanded and the expansion products are fed to the column and/or mixed with the gas phase products passing from the column into the nozzle. Furthermore, the enriched flow or a part thereof is used as a cooling agent for cooling the mixture or the products obtained therefrom, and is compressed, cooled with the aid of the air cooling apparatus and fed into the mixture