Membrane Gas Exchange Module for Natural Gas Purification

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Solution Overview

Problem

Natural gas and biogas contaminated with high levels of hydrogen sulfide and carbon dioxide pose challenges for utilization due to their low methane content and the formation of undesirable sulfur deposits and reduced calorific value, making them unsuitable for direct injection into natural gas networks.

Innovation Solution

A system utilizing two membrane modules, a degassing module and a gas exchange module, where degassed water is used to remove carbon dioxide and hydrogen sulfide from natural gas, increasing the methane content to over 98% without requiring refrigerants, bacteria, or high pressures, and producing no waste or wastewater.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If biogas is used directly in combined heat and power plants, then energy generation is possible, but the low methane content (50-60%) and high content of undesirable gases (CO2, H2S) reduce efficiency and cause operational problems

Engineering Contradiction:
Improveenergy generation efficiencyVSAvoidtoxic effect of carbon dioxide and hydrogen sulfide
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical parameters of the gas mixture by using membrane separation to selectively permeate CO2 and H2S based on their different solubility and diffusion characteristics, thereby increasing methane concentration from 50-60% to above 95% and making the gas suitable for network injection

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent extracts the harmful components (CO2 and H2S) from the biogas mixture using a membrane contactor system, separating these undesirable gases from the methane-rich stream to produce purified natural gas suitable for network injection

Inventive Principle:
Principle #2Taking out (Extraction)

2Manufacturing precision

If membrane technology is used to separate CO2 and H2S from natural gas, then methane content increases to over 95%, but the process requires sophisticated membrane systems and precise control parameters

Engineering Contradiction:
Improvemethane content purityVSAvoidmembrane system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent employs a single membrane contactor system that simultaneously performs multiple functions: CO2 removal, H2S removal, and gas purification, thereby achieving high methane purity (over 95%) without requiring multiple separate processing units or complex control systems

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent uses a selectively permeable membrane as an intermediary substance that facilitates the separation of CO2 and H2S from methane based on differential solubility and permeation rates, achieving high purification precision while maintaining relatively simple system architecture

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If pressure water washing is used to remove CO2 and H2S, then both components are separated simultaneously, but the process requires high pressure operation and subsequent treatment of sulfur-contaminated CO2 exhaust gas

Engineering Contradiction:
Improvegas cleaning efficiencyVSAvoidenergy consumption for pressurization
Core Design Contradiction:
ProductivityVSUse of energy by stationary object

Solution Approach 1:

The patent replaces the mechanical pressurization system of conventional water washing with a membrane-based separation system that operates at or near atmospheric pressure, utilizing the inherent selective permeation properties of the membrane to achieve simultaneous CO2 and H2S removal without high energy consumption for compression

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

The system effectively enriches methane content in natural gas to levels suitable for injection into natural gas networks, avoiding the use of chemicals and reducing energy requirements, while maintaining low operational complexity and environmental impact.

Implementation Method 1

a membrane, in particular a hollow fiber membrane, for separating carbon dioxide and/or hydrogen sulfide from methane-containing natural gas

Methodology Applied
Scientific EffectPermeation: Permeation

Implementation Method 2

Processes based on pressure water washing are based on the principle of different solubilities of CO 2 and methane

Methodology Applied
Scientific EffectDifferential solubility: Absorption (physical)

Data Source

PatentEP2714243B1System and method for treating natural gas that contains methane
Publication Date: 2016.09.14 ING BUSE
  • EP2714243B1 patent drawingFigure 1
  • EP2714243B1 patent drawingFigure 2
  • EP2714243B1 patent drawingFigure 3

AI summary

The invention relates to a system for treating natural gas that contains methane, comprising: a) at least one degassing module (1) and/or at least one percolator, and b) at least one gas exchanging module (2). The invention is characterized in that the degassing module (1) and/or the percolator and the gas exchanging module (2) are connected in a water circuit and arranged successively in the flow direction of the water. The water is degassed in the degassing module (1) and/or percolator, and the degassed water absorbs undesired gases from fed natural gas in the gas exchanging module (2). The fed natural gas is fed to the at least one gas exchanging module (2) in countercurrent to the degassed water. The invention further relates to a method for treating natural gas that contains methane, said method being carried out in the system according to the invention.