Cryogenic Gas Separation Using Condensation and Desublimation

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Solution Overview

Problem

Current methods for separating gases in natural gas production are often energy inefficient, have limited extraction capacity, and are not feasible in remote locations, necessitating the need for energy-efficient and cost-effective purification techniques.

Innovation Solution

A method involving cooling a feed gas stream containing methane, carbon dioxide, and water in a vessel to condense and desublimate components, allowing for simultaneous removal of impurities in a single process step, reducing equipment size and energy consumption, and enabling treatment of high-carbon dioxide natural gas streams.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional gas separation methods are used, then extraction capacity is achieved, but energy consumption increases and facility size expands

Engineering Contradiction:

Improveextraction capacityVSAvoidenergy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent combines multiple separation functions (dehydration, CO2 removal, NGL recovery) into a single cryogenic fractionation unit, eliminating the need for multiple separate equipment trains. This integration maintains high extraction capacity while reducing overall energy consumption by optimizing heat exchange between process streams within the unified system.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention utilizes phase transitions (condensation and freezing) of water, CO2, and NGLs at cryogenic temperatures to achieve separation. By cooling the gas stream to temperatures where these components transition from gas to liquid or solid phases, the system achieves efficient removal of impurities without requiring energy-intensive absorption or adsorption processes.

Inventive Principle:

Principle #36Phase transitions

2Reliability

If multiple separation steps are implemented, then purification effectiveness is improved, but device complexity and facility size increase

Engineering Contradiction:

Improvepurification effectivenessVSAvoidequipment size

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Multiple separation functions are merged into a single cryogenic fractionation vessel where water, CO2, and NGLs are removed simultaneously through controlled cooling. This eliminates the need for separate dehydration units, amine treatment systems, and NGL recovery equipment, significantly reducing facility footprint while maintaining comprehensive purification effectiveness.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The cryogenic fractionation unit performs multiple separation functions universally - it dehydrates the gas stream, removes CO2, and recovers NGLs in one integrated process. This multi-functional approach replaces several specialized equipment pieces with a single versatile unit, reducing overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If conventional purification methods are used, then gas processing is achieved, but health and environmental hazards increase

Engineering Contradiction:

Improvegas processing capacityVSAvoidhealth and environmental hazards

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The system uses cryogenic phase transitions to physically separate and condense harmful components (water, CO2, H2S) from the natural gas stream. This physical separation method avoids the use of chemical solvents like amines that pose health and environmental hazards, while maintaining effective gas processing capacity.

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The invention converts the harmful presence of water, CO2, and NGLs in the gas stream into a benefit by recovering them as valuable liquid or solid products. Water is removed as liquid, CO2 as solid or liquid, and NGLs as liquid condensate that can be sold or utilized, transforming potential hazards into economic assets while protecting public health and the environment.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 effectively removes moisture, carbon dioxide, and NGLs in a single step, reducing treatment facility size, health and environmental hazards, and energy consumption, while avoiding chemical hazards and costs associated with amine absorption technologies.

Implementation Method 1

The feed gas stream is cooled in the vessel such that a portion of the methane, a first portion of the carbon dioxide, and a first portion of the water condense

Methodology Applied

Scientific EffectCondensation: Condensation

Implementation Method 2

Cooling the feed gas stream desublimates a second portion of the carbon dioxide and a second portion of the water as a solid product stream

Methodology Applied

Scientific EffectDesublimation: Sublimation

Data Source

PatentUS10969169B2Method of separating components of a gas

Publication Date: 2021.04.06 U S BANK TRUST CO NAT ASSOC

AI summary

A method is disclosed for separating components of a gas. A feed gas stream is passed into a vessel. The feed gas stream includes methane, carbon dioxide, and water. The feed gas stream is cooled in the vessel such that a portion of the methane and a portion of the carbon dioxide condense and a portion of the water desublimates, resulting in a product stream and a depleted gas stream exiting the vessel.