Hydrocracking Sediment Precipitation for Fuel Stability
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Solution Overview
Problem
Current processes for converting heavy hydrocarbon fractions with sulphur-containing impurities into fuel oils, such as bunker fuels, struggle to meet stringent sediment content requirements after aging, particularly ISO 10307-2 standards, due to high sediment formation during hydrocracking, which leads to unstable residual cuts and potential engine fouling.
Innovation Solution
A process involving ebullated bed hydrocracking followed by a precipitation step and physical separation of sediments using a distillate cut, achieving a sediment content of 0.1% or less after aging, thereby producing stable fuel oils that comply with ISO 10307-2 specifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrocracking is operated under severe conditions leading to high degree of conversion, then conversion efficiency is improved, but sediment content increases and stability deteriorates
Solution Approach 1:
The patent applies preliminary action by conducting a precipitation step before the residual cut is used as fuel oil. The heavy fraction from hydrocracking is mixed with a solvent and held at elevated temperature to precipitate sediments, then the precipitated sediments are removed by decantation or filtration. This preliminary treatment prevents sediment formation in the final product while allowing severe hydrocracking conditions to achieve high conversion efficiency.
2Productivity
If hydrocracking is operated under severe conditions leading to high degree of conversion, then conversion efficiency is improved, but sediment content increases
Solution Approach 1:
The patent applies the extraction principle by removing sediments from the heavy fraction through a precipitation and separation process. The heavy fraction is mixed with a solvent (such as n-heptane, n-pentane, or toluene) and held at 50-200°C to precipitate sediments, which are then separated by decantation or filtration. This extraction of sediments reduces the sediment content in the final fuel oil product while maintaining high conversion efficiency from severe hydrocracking conditions.
3Manufacturing precision
If sediment content is reduced to meet ISO 10307-2 specification, then product quality is improved, but process complexity increases
Solution Approach 1:
The patent applies the intermediary principle by introducing a solvent as a mediating substance to facilitate sediment precipitation and separation. The solvent (such as n-heptane, n-pentane, toluene, or their mixtures) acts as an intermediary that promotes the precipitation of sediments from the heavy fraction when mixed and held at elevated temperature. This intermediary substance enables effective sediment removal through simple decantation or filtration, achieving ISO 10307-2 compliance without requiring complex processing equipment or multiple treatment stages.
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 reduces sediment content in heavy fractions, preventing engine fouling and enabling the production of bunker fuels with improved stability and compliance with regulatory standards, while also avoiding catalyst bed fouling.
Implementation Method 1
a step for precipitating the sediments, in which the heavy fraction obtained from the separation step b) is brought into contact with a distillate cut
Data Source
AI summary
The invention concerns a process for converting a hydrocarbon feed, said process comprising the following steps: a) a step of hydrocracking the feed in the presence of hydrogen; b) a step of separating the effluent obtained from step a); c) a step of precipitating sediments, in which the heavy fraction obtained from the separation step b) is brought into contact with a distillate cut at least 20% by weight of which has a boiling point of 100° C. or more for a period of less than 500 minutes, at a temperature in the range 25° C. to 350° C., and at a pressure of less than 20 MPa; d) a step of physical separation of the sediments from the heavy fraction obtained from step c); e) a step of recovering a heavy fraction having a sediment content, measured using the ISO 10307-2 method, of 0.1% by weight or less.