Fischer-Tropsch Wax Hydrogenation and De-oiling Sequence
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Solution Overview
Problem
Paraffinic waxes derived from Fischer-Tropsch hydrocarbon synthesis are difficult to de-oil efficiently to achieve low oil content and desirable color properties, requiring multiple de-oiling stages and increasing capital costs.
Innovation Solution
Reversing the traditional processing sequence by first hydrogenating the wax and then de-oiling, using fractional crystallization at temperatures below 80°C, and employing a catalyst like NiSat 310 to convert oxygenated components into removable hydrocarbons, thereby reducing oil content to less than 0.5 weight % MEK-solubility and achieving desired color stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional de-oiling sequence is used first, then oil components are removed by solvent extraction, but subsequent hydrogenation is required as a final polishing step to achieve color specification
Solution Approach 1:
The patent inverts the traditional processing sequence by performing hydrogenation first to convert oxygenated components (aldehydes, ketones) into hydrocarbons, then performing de-oiling to remove the converted components along with other oil components in a single step. This reversal eliminates the need for a subsequent hydrogenation polishing step while achieving the same color specification.
Solution Approach 2:
The patent applies preliminary hydrogenation action before de-oiling to convert oxygenated components that would otherwise require a final polishing hydrogenation step. By performing this conversion in advance, the process consolidates all necessary treatments into one sequence, simplifying the overall manufacturing process.
2Manufacturing precision
If multiple de-oiling stages are used to achieve low oil content, then oil content specification is met, but capital costs increase
Solution Approach 1:
The patent changes the chemical parameters of the wax by performing hydrogenation first, converting oxygenated components into hydrocarbons that have different solubility characteristics. This parameter change allows all oil components to be removed more efficiently in a single de-oiling stage, reducing the number of stages required and lowering capital costs.
3Ease of manufacture
If oxygenated components are present in the wax, then the wax can be processed with simpler initial treatment, but the wax develops undesirable color properties
Solution Approach 1:
The patent converts the harmful oxygenated components (aldehydes, ketones) into beneficial hydrocarbons through preliminary hydrogenation. This conversion transforms substances that would cause color deterioration into components that can be easily removed during the subsequent de-oiling step, eliminating the color problem while simplifying the overall process.
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 significantly reduces the number of de-oiling stages required, improving efficiency and meeting product specifications with lower capital costs, while ensuring color stability and low oil content in the wax product.
Implementation Method 1
hydrogenating the wax first, followed by de-oiling thereof. Although not wishing to be bound by theory, it is believed that certain waxes contain particular molecule species, e.g. oxygenates, in concentrations which are extremely difficult to de-oil. If however the wax is first hydrogenated these molecule species are converted to hydrocarbons which are readily removed by de-oiling.
Implementation Method 2
employing a catalyst like NiSat 310 to convert oxygenated components into removable hydrocarbons
Implementation Method 3
then de-oiling, using fractional crystallization at temperatures below 80°C
Data Source
Figure 1
AI summary
A method of treating or refining a wax includes hydrogenating a feed wax which has an MEK-solubility oils content of more 0.5 weight % to provide a hydrogenated wax. Thereafter the hydrogenated wax is de-oiled to reduce the MEK-solubility oils content of the hydrogenated wax, producing a refined wax or a wax product.