Fischer-Tropsch Wax Hydrogenation for Colour and Congealing Control

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Solution Overview

Problem

Existing processes for producing Fischer-Tropsch derived waxes result in products with congealing points above 100°C and low Saybolt colours, primarily due to the lack of a hydrogenation step, which affects the quality and stability of the waxes.

Innovation Solution

A process involving a Fischer-Tropsch product stream hydrogenation followed by distillation and hydrofinishing to produce wax products with varying congealing points and high Saybolt colours, utilizing a single hydrogenation unit for fractions ranging from 10 to 300 carbon atoms, enhancing stability and quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If distillation is performed without preceding hydrogenation, then process complexity is reduced, but Saybolt colour quality deteriorates

Engineering Contradiction:
Improveprocess complexityVSAvoidSaybolt colour quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

Hydrogenation is performed as a preliminary step before distillation to improve the Saybolt colour quality of the wax products. By saturating unsaturated hydrocarbons and removing impurities through hydrogenation beforehand, the subsequent distillation produces higher quality wax with improved colour characteristics.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If multiple separate hydrogenation units are used for different carbon fractions, then hydrogenation effectiveness is improved, but device complexity and cost increase

Engineering Contradiction:
Improvehydrogenation effectivenessVSAvoidnumber of hydrogenation units
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

A single hydrogenation unit is designed to handle multiple carbon fractions (C10-C17 and C18-C300) simultaneously or sequentially. The unit is equipped with adjustable parameters such as temperature, pressure, and catalyst selection to optimize hydrogenation for different feedstock compositions, eliminating the need for separate dedicated units for each fraction.

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

3Manufacturing precision

If hydrogenation is performed, then Saybolt colour and stability are improved, but process complexity and operational costs increase

Engineering Contradiction:
ImproveSaybolt colour and stabilityVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The hydrogenation step is merged with the existing distillation process by integrating it as a preliminary treatment stage. The hydrogenation unit processes the Fischer-Tropsch product stream before it enters the distillation column, combining two previously separate operations into a unified process flow that improves quality without proportionally increasing complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 produces wax products with high congealing points and high Saybolt colours, improving stability against degradation and quality, while reducing operational and installed costs by using a single hydrogenation unit.

Implementation Method 1

the Fischer-Tropsch product stream is converted to a hydrogenated Fischer-Tropsch product stream in a hydrogenation step

Methodology Applied
Scientific EffectHydrogenation: Hydrogenation

Implementation Method 2

the hydrogenated Fischer-Tropsch product stream is separated in a distillation column to obtain at least a fraction comprising 10 to 17 carbon atoms and a fraction comprising 18 to 300 carbon atoms

Methodology Applied
Scientific EffectDistillation: Distillation

Data Source

PatentEP3240873B1Process to prepare paraffin wax
Publication Date: 2023.08.16 SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ BV
  • EP3240873B1 patent drawingFigure 1

AI summary

The present invention provides a process to prepare paraffins and waxes, the process at least comprising the following steps: (a) providing a Fischer-Tropsch product stream comprising paraffins having from 10 to 300 carbon atoms; (b) subjecting the Fischer-Tropsch product stream of step (a) to a hydrogenation step, thereby obtaining a hydrogenated Fischer-Tropsch product stream comprising 10 to 300 carbon atoms; (c) separating the hydrogenated Fischer-Tropsch product stream of step (b), thereby obtaining at least a fraction comprising 10 to 17 carbon atoms and a fraction comprising 18 to 300 carbon atoms; (d) separating the hydrogenated fraction comprising 18 to 300 carbon atoms of step (c), thereby obtaining one or more first light waxes having a congealing point in the range of 30 to 75°C and a second heavy wax having a congealing point in the range of 75 to 120°C; e) hydrofinishing one or more wax fractions having a congealing point in the range of 30 to 75°C of step (d) thereby obtaining one or more hydrofinished wax fractions having a congealing point in the range of 30 to 75°C.