Fuel Oil Cold Flow Additives via Terpolymer Branching
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Solution Overview
Problem
Existing cold flow additives for fuel oils, particularly those based on ethylene-vinyl ester copolymers, face issues with solubility and effectiveness at low temperatures, leading to filter blockages and reduced performance due to insoluble fractions and short-chain branching, which complicates handling and processing in modern engine technologies.
Innovation Solution
The development of additive mixtures comprising terpolymers of ethylene, propene, and unsaturated esters with controlled branching and molecular weight, combined with copolymers or comb polymers, to enhance solubility and effectiveness as cold flow improvers, allowing for improved handling and reduced filter blockages at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ethylene-vinyl ester copolymers are used as cold flow additives, then crystal seed formation is improved, but solubility deteriorates leading to filter blockages
Solution Approach 1:
The patent changes the compositional parameters of the copolymer by controlling the vinyl ester content (15-35 mol%) and introducing controlled short-chain branching (5-20 methyl groups per 100 CH2 groups). This parameter optimization balances the competing requirements: sufficient vinyl ester content for solubility and controlled branching for crystal seed formation capability, eliminating filter blockages while maintaining cold flow improvement effectiveness.
2Reliability
If ethylene copolymers with low comonomer content are used for high cocrystallization, then crystal seed formation is enhanced, but handling and transport become difficult due to elevated crystallinity
Solution Approach 1:
The patent optimizes the vinyl ester comonomer content to a specific range (15-35 mol%) that disrupts the crystalline structure sufficiently to improve handling and transport properties, while maintaining enough polyethylene sequence length to enable effective cocrystallization with paraffins. This parameter window resolves the contradiction between handling ease and cocrystallization effectiveness.
Solution Approach 2:
The patent creates a composite polymer structure combining polyethylene sequences (for cocrystallization) with vinyl ester units (for solubility and handling improvement). The controlled short-chain branching from propene units further modifies the composite structure to reduce crystallinity while preserving the essential cocrystallization capability.
3Object-affected harmful factors
If hydrogenating desulfurization is increased for environmental compliance, then sulfur content is reduced, but proportion of cold-critical paraffins increases
Solution Approach 1:
The patent adjusts the additive composition parameters to match the altered fuel composition resulting from hydrogenating desulfurization. The controlled vinyl ester content and branching structure are optimized to be effective specifically in low-sulfur, high-paraffin fuels, maintaining cold flow improvement effectiveness despite the increased proportion of cold-critical paraffins.
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
These additive mixtures exhibit superior cold flow improvement and solubility in fuel oils at low temperatures, preventing filter blockages and enabling use without prior heating, while reducing transport and storage costs through lower solvent requirements.
Implementation Method 1
n-paraffins which crystallize out as platelet-shaped crystals when the temperature is reduced
Implementation Method 2
constituents which act as additional crystal seeds, crystallize out with the paraffins and bring about a larger number of smaller paraffin crystals with modified crystal form (nucleates)
Implementation Method 3
copolymers of ethylene and vinyl esters... whose mode of action is explained by cocrystallization of their poly(ethylene) sequences with the n-paraffins which precipitate out of the middle distillates in the course of cooling
Data Source
AI summary
The invention provides additive mixtures comprisingA) at least one terpolymer of ethylene, propene and at least one ethylenically unsaturated ester, whichi) contains from 6.0 to 12.0 mol % of structural units derived from at least one ethylenically unsaturated ester having a C1- to C3-alkyl radical,ii) contains from 0.5 to 4.0 methyl groups derived from propene per 100 aliphatic carbon atoms,iii) has fewer than 8.0 methyl groups stemming from chain ends per 100 CH2 groups, andB) from 0.5 to 20 parts by weight, based on A), of at least one further componentwhich is effective as a cold additive for mineral oils and is selected fromB1) copolymers of ethylene and ethylenically unsaturated compounds whose content of ethylenically unsaturated compounds is at least 2 mol % higher than the content of ethylenically unsaturated esters in the terpolymer defined under A),B2) comb polymers, andB3) mixtures of B1) and B2),and also their use as a cold additive for middle distillates.