Produced Gas Separation Using CO2 Liquefaction and Injection

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Solution Overview

Problem

Current gas processing technologies fail to rapidly and ecologically acceptably dispose of unusable gases like carbon dioxide and hydrogen sulfide from produced gas, often venting them into the atmosphere, which is undesirable due to environmental concerns and economic factors.

Innovation Solution

A process that dehydrates and cools produced gas to separate hydrocarbon gases from waste gases like carbon dioxide and hydrogen sulfide, converting these waste gases into a liquid form for injection into a separate injection well, where they can be disposed of in a controlled manner, enhancing hydrocarbon recovery by pressurizing and injecting them back into a suitable stratum.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If waste gases like carbon dioxide and hydrogen sulfide are vented into the atmosphere, then disposal is simple and quick, but environmental harm increases and ecological acceptability deteriorates

Engineering Contradiction:

Improvedisposal speedVSAvoidenvironmental harm

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies phase transition by cooling waste gases to convert them from gaseous to liquid state. This enables the gases to be injected into underground formations as liquids, achieving both rapid disposal and environmental protection. The phase change allows the waste gases to be handled and disposed of in a controlled manner that prevents atmospheric venting while maintaining disposal efficiency.

Inventive Principle:

Principle #36Phase transitions

2Object-affected harmful factors

If waste gases are converted to liquid form for injection well disposal, then ecological acceptability improves and atmospheric venting is prevented, but process complexity and equipment requirements increase

Engineering Contradiction:

Improveecological acceptabilityVSAvoidprocess complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent changes the temperature parameter of the waste gases, cooling them to conditions where they transition to liquid state. This parameter change enables injection into underground formations while avoiding the need for complex compression or chemical treatment systems. By controlling temperature, the process achieves ecological acceptability with relatively simple equipment.

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If produced gas is cooled to separate waste gases in liquid form, then separation efficiency improves and waste gas disposal becomes environmentally acceptable, but energy consumption increases

Engineering Contradiction:

Improveseparation efficiencyVSAvoidcooling energy consumption

Core Design Contradiction:

Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent converts the harmful waste gases into a beneficial disposal form by cooling them to liquid state. The same cooling process that separates the waste gases also prepares them for beneficial injection into depleted oil or gas formations, where they can maintain pressure and potentially enhance recovery. This transforms what would be a pure waste stream into a resource that can support productive operations.

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 method effectively prevents atmospheric venting of harmful gases, economically enhances hydrocarbon recovery by utilizing waste gases to stimulate production from nearby wells, and ensures ecological acceptability by disposing of waste gases underground.

Implementation Method 1

The produced gas is cooled to a temperature in which at least some of the waste gas such as carbon dioxide is in liquid form

Methodology Applied

Scientific EffectCondensation: Condensation

Implementation Method 2

The cooled and dehydrated produced gas is then processed into a first stream containing desired hydrocarbons and a second stream containing waste gases in liquid form

Methodology Applied

Scientific EffectFractionation: Fractionation

Data Source

PatentUS7914606B2System for separating a waste liquid and a hydrocarbon gas from a produced gas

Publication Date: 2011.03.29 KATHY ANN STINSON NICHOLES IN HER REPRESENTATIVE CAPACITY AS TRUSTEE OF THE DONALD L STINSON 1994 TRUST U A DTD OCTOBER 24 1994 AS AMENDED

AI summary

Produced natural gas containing carbon dioxide is dehydrated and chilled to liquefy the carbon dioxide and then fractionated to produce a waste stream of liquid carbon dioxide and hydrogen sulfide. Natural gas liquids may be first separated and removed before fractionation. After fractionation, the waste stream is pressurized and transmitted to a remote injection well for injection either for disposal of the waste stream and preferably to urge hydrocarbons toward the producing well. A hydrocarbon stream proceeds from fractionation to a methanol absorber system which removes carbon dioxide gas. The hydrocarbon stream is thereafter separated into at least hydrocarbon gas, nitrogen and helium. Some of the nitrogen is reintroduced into a fractionation tower to enhance the recovery of hydrocarbons. A methanol recovery system is provided to recover and reuse the methanol. The hydrocarbons are sold as natural gas and the helium is recovered and sold. Excess nitrogen is vented.