FT Diesel Blend Cold Flow via Wax Crystal Modification
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Solution Overview
Problem
Fischer Tropsch (FT) derived diesel fuels exhibit reduced effectiveness of Cold Filter Plugging Point (CFPP) additives when blended with crude oil derived diesel, particularly in narrow cut fuels, leading to inadequate cold flow properties in cold climates.
Innovation Solution
A blend of FT derived diesel, crude derived diesel, and a CFPP improving additive, where the FT diesel is from 1 vol % to 50 vol % of the blend, with the CFPP improving additive typically in the range of 50 ppm to 1000 ppm, achieving a CFPP below −18° C., effectively improving cold flow properties by modifying wax crystal growth and precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If FT derived diesel is blended with crude oil derived diesel, then the fuel composition is improved for cold flow, but the effectiveness of CFPP additives deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the diesel fuel by blending FT derived diesel (rich in n-paraffins) with crude oil derived diesel in specific ratios (1-50 vol% FT diesel). This parameter change modifies the wax precipitation characteristics and crystal growth rates, creating a fuel matrix where CFPP additives can effectively co-crystallize with wax molecules to prevent filter plugging.
Solution Approach 2:
The invention creates a composite fuel system combining three components: FT derived diesel, crude oil derived diesel, and CFPP additives. This composite material approach leverages the complementary properties of each component - the n-paraffin content of FT diesel provides wax molecules for additive interaction, the crude oil diesel provides a stable base, and the additives modify crystal growth to maintain flowability.
2Speed
If the rate of crystal growth is rapid, then wax separates quickly from fuel, but large crystals form that block filters
Solution Approach 1:
CFPP additives act as intermediaries between wax molecules and the fuel matrix. These additives co-crystallize with separating wax molecules, modifying the crystal growth process to produce numerous small crystals instead of few large crystals. The additives mediate the interaction between wax and fuel, preventing harmful filter blockage while maintaining the necessary wax precipitation process.
Solution Approach 2:
The invention changes the kinetic parameters of crystal growth by introducing additives that alter the nucleation and growth rates. The additives modify the crystal growth parameter from rapid formation of large crystals to controlled formation of many small crystals, changing the size distribution parameter to prevent filter plugging while maintaining wax separation.
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 blend demonstrates improved cold flow properties, with CFPP below −20° C. even at low FT diesel concentrations, maintaining engine operability in cold temperatures without significant deterioration, as shown in various experimental results.
Implementation Method 1
Nucleation: Additive composition is adjusted such that at the fuel cloud point many artificial nuclei become available on which wax crystals grow. Growth arresting: During crystal growth around the nuclei, additive molecules also act to prevent further growth.
Implementation Method 2
As a fuel is cooled to its cloud point, the normal paraffins begin to separate from the fuel wax. Upon further cooling, more wax appears and adds to these initial crystals.
Data Source
AI summary
The invention provides a blend of FT derived diesel, crude derived diesel, and CFPP improving additive, wherein the FT diesel is from 1 vol % to 50 vol % of the blend, said blend having a CFPP of below −18° C. The invention extends to use of FT diesel as a blend component for a compression ignition fuel blend, said blend including the FT diesel, a crude derived diesel fuel and a CFPP improver additive, wherein the FT diesel is from 1 vol % to 50 vol % of the blend, which blend has a CFPP of below −20° C.