Ionic Liquid Extraction for Heavy Oil Nitrogen Removal
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Solution Overview
Problem
Heavy oils contain nitrogen contaminants that are difficult to remove during processing, leading to environmental pollution and catalyst poisoning, and existing methods like hydrotreating are inefficient due to the high aromaticity of these compounds.
Innovation Solution
A process involving the use of hydrocarbon-immiscible ionic liquids, such as imidazolium, ammonium, and phosphonium ionic liquids, to extract nitrogen compounds from hydrocarbon streams, which can be repeated multiple times to achieve up to 100% nitrogen compound extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If hydrotreating processes are used to remove nitrogen compounds from heavy oil fractions, then nitrogen content is reduced, but the process requires excessive energy and hydrogen due to high aromaticity of nitrogen compounds
Solution Approach 1:
The patent applies liquid-liquid extraction using ionic liquids to selectively remove nitrogen compounds from hydrocarbon streams before hydrotreating. The ionic liquid phase contacts the hydrocarbon phase in an extraction column, transferring nitrogen compounds from the hydrocarbon phase to the ionic liquid phase based on solubility differences. This pre-extraction step reduces nitrogen content and aromaticity, making subsequent hydrotreating more energy-efficient and less hydrogen-intensive.
Solution Approach 2:
The patent introduces ionic liquids as an intermediary substance between the hydrocarbon feed and the hydrotreating process. These ionic liquids act as a mediator that selectively binds to nitrogen compounds through π-π interactions and other molecular forces, facilitating their removal without requiring direct high-energy hydrotreating of aromatic nitrogen compounds. The ionic liquid can be regenerated and reused, making the overall process more sustainable.
2Quantity of substance
If nitrogen compounds are removed by adsorption onto solid particles or catalysts, then nitrogen content is reduced, but catalyst poisoning occurs and adsorbent capacity is limited
Solution Approach 1:
The patent uses ionic liquids as an intermediary extraction medium that selectively removes nitrogen compounds before they can contact and poison catalysts in downstream processing units. By placing the ionic liquid extraction step upstream, nitrogen-laden hydrocarbons are separated from the catalyst contact zone, protecting catalyst activity and extending its life. The ionic liquid phase accumulates the nitrogen compounds, isolating them from the catalytic materials.
3Productivity
If heavy oils are upgraded through coking or hydrocracking, then lighter fuel products are produced, but substantial amounts of coke are formed as by-product
Solution Approach 1:
The patent applies ionic liquid extraction as a preliminary treatment step before coking or hydrocracking processes. By removing nitrogen compounds and other contaminants upfront, the feedstock entering the upgrading units has lower impurity content, which reduces coke precursor formation during thermal cracking. This pre-cleaning action leads to lower coke yields in delayed coking or fluidized coking units, improving overall carbon efficiency and reducing by-product disposal requirements.
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 process effectively reduces nitrogen content in heavy oil products, making them suitable for further processing by enhancing the efficiency of nitrogen removal and reducing the energy required for hydrotreating, thereby improving the economic viability of upgrading heavy oils.
Implementation Method 1
contacting the hydrocarbon stream comprising the nitrogen compound with a hydrocarbon-immiscible ionic liquid to produce a mixture comprising the hydrocarbon stream and the hydrocarbon stream-immiscible ionic liquid
Implementation Method 2
separating the mixture to produce a hydrocarbon stream effluent and a hydrocarbon stream-immiscible ionic liquid effluent comprising the nitrogen compounds
Data Source
AI summary
The invention involves a process for hydrocarbon conversion. The process can include providing a feed to a primary upgrading zone and then treating the product from the primary upgrading zone with a feed-immiscible ionic liquid to remove nitrogen compounds.