Fischer-Tropsch Tail Gas Hydrotreating for Alkene Purification

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Solution Overview

Problem

The Fischer-Tropsch process generates a tail gas stream that is typically wasted, and there is a need for an improved process to purify hydrocarbon products from this stream.

Innovation Solution

A process is developed to convert alkenes in a hydrocarbon stream to alkanes using the full non-liquid gas stream from an upstream Fischer Tropsch reaction without gas separation, achieving alkene content reduction to less than 1% via hydro-treating, and utilizing temperature and space velocity requirements in the presence of a mixed Fischer Tropsch tail gas stream.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the Fischer-Tropsch process is used to convert syngas to hydrocarbons, then hydrocarbon products are generated, but a tail gas stream containing alkenes is produced that requires purification

Engineering Contradiction:

Improvehydrocarbon production yieldVSAvoidalkene content in tail gas

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful alkene-containing tail gas stream into a beneficial resource by directing it to a hydro-treating unit where alkenes are hydrogenated to alkanes. This transforms the waste product into useful hydrocarbon products, eliminating the need for separate gas separation processes and improving overall process efficiency.

Inventive Principle:

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

Solution Approach 2:

The patent merges the hydro-treating operation with the existing Fischer-Tropsch process flow by integrating the hydro-treating unit directly into the process stream. This combination allows simultaneous production of hydrocarbon products and purification of the tail gas stream, reducing process complexity and improving productivity.

Inventive Principle:

Principle #5Merging (Combining)

2Object-generated harmful factors

If traditional gas separation methods are used to remove alkenes, then alkene content is reduced, but process complexity and equipment requirements increase

Engineering Contradiction:

Improvealkene contentVSAvoidgas separation equipment

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces mechanical gas separation methods with a chemical hydro-treating process. Instead of using physical separation techniques that require complex equipment, the process uses catalytic hydrogenation to chemically convert alkenes to alkanes, simplifying the overall system and reducing equipment requirements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the chemical parameters of the tail gas stream by introducing hydrogen and using a catalyst to facilitate hydrogenation. This parameter change transforms the alkene-rich stream into an alkane-rich stream, achieving purification through chemical transformation rather than physical separation.

Inventive Principle:

Principle #35Parameter changes

3Object-generated harmful factors

If hydro-treating is applied to convert alkenes to alkanes, then alkene content is reduced to less than 1%, but temperature and space velocity control becomes critical

Engineering Contradiction:

Improvealkene contentVSAvoidtemperature and space velocity control

Core Design Contradiction:

Object-generated harmful factorsVSEase of operation

Solution Approach 1:

The patent implements feedback control mechanisms to monitor and adjust temperature and space velocity parameters in the hydro-treating unit. By continuously monitoring these parameters and making real-time adjustments, the process maintains optimal conditions for alkene conversion while preventing excessive temperature rises or residence time issues.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent employs dynamic control of the hydro-treating process, allowing temperature and space velocity to be adjusted based on feedstock composition and process conditions. This dynamic approach enables the system to adapt to varying operating conditions while maintaining consistent alkene conversion performance.

Inventive Principle:

Principle #15Dynamics

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 process effectively reduces alkene content to less than 1% and optimizes hydrocarbon product purification by integrating hydro-treating steps within the Fischer Tropsch process flow, enhancing the efficiency and yield of hydrocarbon production.

Implementation Method 1

convert alkenes in a hydrocarbon stream to alkanes using the full non-liquid gas stream from an upstream Fischer Tropsch reaction without gas separation, achieving alkene content reduction to less than 1% via hydro-treating

Methodology Applied

Scientific EffectHydrogenation: Hydrogenation

Implementation Method 2

The Fischer-Tropsch process is a GTL polymerization technique that turns a carbon source into hydrocarbons chains through the hydrogenation of carbon monoxide by means of a metal catalyst

Methodology Applied

Scientific EffectHydrogenation: Hydrogenation

Implementation Method 3

The Fischer-Tropsch process is a GTL polymerization technique that turns a carbon source into hydrocarbons chains through the hydrogenation of carbon monoxide by means of a metal catalyst

Methodology Applied

Scientific EffectCatalysis: Catalysis