Fischer-Tropsch Hydroprocessing Catalyst for Cold Flow and Yield
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Solution Overview
Problem
Existing processes for producing middle distillates and base oils from Fischer-Tropsch products face challenges in achieving premium quality with adequate cold flow properties and yield, often requiring additional dewaxing steps that incur capital expenditure and yield loss.
Innovation Solution
A hydroprocessing step using a catalyst with a molecular sieve of 5-7 angstrom pore size and a SiO2/Al2O3 ratio of at least 25, combined with a Group VIII metal, to produce middle distillates and base oils, allowing for improved cold flow properties and high viscosity index without separate catalytic dewaxing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a high conversion per pass is used to improve cold flow properties of middle distillates, then cold flow properties are improved, but yield loss on valuable distillate base oil fraction occurs
Solution Approach 1:
The patent changes the chemical parameters of the catalyst system by using a specific molecular sieve with pore size 5-7 angstrom and SiO2/Al2O3 ratio of at least 25, combined with a Group VIII metal. This parameter change enables effective dewaxing at lower conversion per pass, resolving the contradiction between improving cold flow properties and maintaining yield.
2Quantity of substance
If conventional hydroconversion catalysts are used to produce middle distillates and base oils, then base oils are obtained, but additional dewaxing steps are required which increase capital expenditure and yield loss
Solution Approach 1:
The patent merges the hydroconversion and dewaxing functions into a single catalytic step by using a molecular sieve catalyst with specific properties (pore size 5-7 angstrom, SiO2/Al2O3 ratio ≥25, Group VIII metal). This consolidation eliminates the need for separate dewaxing units, reducing capital expenditure and process complexity while maintaining base oil production.
3Manufacturing precision
If conventional catalysts are used for hydroconversion, then middle distillates are produced, but premium quality with adequate cold flow properties cannot be achieved without additional processing
Solution Approach 1:
The patent achieves premium quality middle distillates with adequate cold flow properties by changing the catalyst parameters to a molecular sieve with pore size 5-7 angstrom and SiO2/Al2O3 ratio of at least 25 containing a Group VIII metal. This single catalytic step produces high-quality products without requiring additional processing steps, resolving the contradiction between manufacturing precision and ease of manufacture.
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 results in premium quality middle distillates and base oils with low pour points and high viscosity indices, suitable for applications in process oils and lubricants, without the need for additional dewaxing, thereby reducing capital expenditure and maintaining yield.
Implementation Method 1
both catalysts have hydrocracking and hydroisomerising activity
Implementation Method 2
the second catalyst is more active in hydroisomerisation and less active in hydrocracking compared to the first catalyst
Implementation Method 3
in the presence of a catalyst comprising a molecular sieve with a pore size between 5 and 7 angstrom and a SiO2/Al2O3 ratio of at least 25, preferably from 50 to 180 and a group VIII metal
Implementation Method 4
by using a catalyst comprising a molecular sieve with a pore size between 5 and 7 angstrom and a SiO2/Al2O3 ratio of at least 25
Implementation Method 5
catalyst comprising a molecular sieve with a pore size between 5 and 7 angstrom
Implementation Method 6
separating the mixture as obtained in step (a) by means of atmospheric distillation into one or more middle distillate fractions, a first residual fraction and a naphtha fraction
Implementation Method 7
separating the first residual fraction by means of vacuum distillation into at least a distillate base oil fraction and a second residual fraction
Data Source
AI summary
The present invention provides a process to prepare middle distillates and base oils from a Fischer-Tropsch product, by(a) subjecting the Fischer-Tropsch product to a hydroprocessing step in the presence of a catalyst comprising a molecular sieve with a pore size between 5 and 7 angstrom and a SiO2/Al2O3 ratio of at least 25, preferably from 50 to 180 and a group VIII metal to obtain a mixture comprising one or more middle distillate fractions and a first residual fraction and a naphtha fraction;(b) separating the mixture as obtained in step (a) by means of atmospheric distillation into one or more middle distillate fractions, a first residual fraction and a naphtha fraction;(c) separating the first residual fraction by means of vacuum distillation into at least a distillate base oil fraction and a second residual fraction.