Hydrocarbon Refining Solvent Extraction for PAH Recovery
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Solution Overview
Problem
Conventional petroleum refining methods struggle to efficiently extract and preserve polynuclear aromatic hydrocarbons, refractory heterocyclic organic compounds, and organometallic compounds from crude oil, leading to energy-intensive processes and loss of valuable materials, as these compounds are often destroyed during hydrotreatment, limiting their application in fine chemicals and renewable energy technologies.
Innovation Solution
A method using a tunable solvent system formed from pressurized carbon dioxide and water to selectively extract heteroatom compounds and polynuclear aromatic hydrocarbons from hydrocarbon feedstocks, followed by an aprotic solvent system to produce a hydrocarbon raffinate with reduced heteroatom and PAH levels, allowing for their recovery and utilization in advanced applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional hydrotreatment is used to remove heterocyclic compounds and PAHs from hydrocarbon feedstocks, then sulfur and nitrogen content is reduced, but the molecular structure of valuable compounds is destroyed and energy consumption increases
Solution Approach 1:
The patent applies extraction using a polar solvent to selectively remove heterocyclic compounds and PAHs from the hydrocarbon feedstock before hydrotreatment. This separates the harmful compounds (containing sulfur and nitrogen) from the valuable hydrocarbon molecules, allowing the latter to undergo milder treatment that preserves their molecular structure while still achieving the required sulfur and nitrogen removal efficiency.
Solution Approach 2:
The extraction step is performed as a preliminary action before hydrotreatment. By removing heterocyclic compounds and PAHs in advance, the subsequent hydrotreatment process operates on a feedstock with lower concentrations of these compounds, reducing the energy required for sulfur and nitrogen removal and preventing the destruction of valuable aromatic hydrocarbons.
2Loss of substance
If heterocyclic compounds and PAHs are extracted using conventional methods, then they can be recovered, but the process complexity increases and selectivity is reduced
Solution Approach 1:
The patent utilizes the polarity parameter of the solvent to achieve selective extraction. By choosing a polar solvent, the process selectively targets heterocyclic compounds and PAHs based on their polar characteristics, separating them from non-polar hydrocarbons. This single parameter change (solvent polarity) provides both the selectivity needed for recovery and simplifies the overall process compared to multiple separation steps.
3Quantity of substance
If cracking is used to break down resins and asphaltenes to release heterocyclic compounds and PAHs, then these compounds become available for separation, but the molecular structure of valuable compounds is fragmented and energy consumption increases
Solution Approach 1:
Instead of using cracking to break down resins and asphaltenes (which would fragment valuable molecules), the patent converts the harmful effect of these macromolecules by using their polarity characteristics. The polar solvent selectively extracts heterocyclic compounds and PAHs that are associated with resins and asphaltenes, making them available for separation without requiring molecular fragmentation. This preserves the integrity of valuable aromatic hydrocarbons while still achieving compound availability.
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 energy costs in hydrotreatment processes, preserves the molecular structure of valuable compounds, and enables their use in fine chemicals, organic solar cells, and other advanced technologies, enhancing the economic and environmental sustainability of petroleum refining.
Implementation Method 1
A method using a tunable solvent system formed from pressurized carbon dioxide and water to selectively extract heteroatom compounds and polynuclear aromatic hydrocarbons from hydrocarbon feedstocks
Implementation Method 2
followed by an aprotic solvent system to produce a hydrocarbon raffinate with reduced heteroatom and PAH levels
Data Source
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AI summary
Methods are provided for extracting heterocyclic compounds, organometallic compounds, and polynuclear aromatic hydrocarbons from a hydrocarbon feedstock such as crude oil or a crude fraction. The heterocyclic compounds and organometallic compounds are removed from the hydrocarbon feedstock through one or more successive extractions to form a first raffinate. The extractions use a first solvent system containing an ionic liquid formed from carbon dioxide and water. The polynuclear aromatic hydrocarbons are removed from the first raffinate using a second solvent system containing an aprotic solvent such as NMP, DMSO, aromatics, or combinations thereof. The extracted compounds remain chemically intact and may be fractionated for further applications. Further methods are provided for producing a hydrocarbon raffinate having reduced levels of heterocyclic compounds, organometallic compounds, and 2-4 cycle polynuclear aromatic hydrocarbons.