Ionic Liquid Alkylation for Middle Distillate Production
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Solution Overview
Problem
Current alkylation and refinery processes face challenges in producing middle distillate with low sulfur and olefin content, which are essential for high-value products like diesel, jet fuel, and kerosene, as existing methods often result in high sulfur and olefin levels, affecting oxidation stability and product quality.
Innovation Solution
An alkylation process using an ionic liquid catalyst, specifically an acidic ionic liquid comprising a Lewis Acidic compound and an organic salt, in combination with a halide containing additive, is employed to contact an isoparaffin feed rich in C5+ hydrocarbons with a hydrocarbon stream containing C5+ olefins, achieving high yields of middle distillate with reduced sulfur and olefin content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional alkylation processes are used to produce middle distillate, then production efficiency is maintained, but sulfur and olefin content in the product remains high, compromising oxidation stability and product quality
Solution Approach 1:
The patent changes the chemical parameters of the alkylation process by using acidic ionic liquid catalysts with specific acidities (Hammett acidity function H0 between -10 to -18) and controlling the molar ratio of olefin to isoparaffin (0.05 to 0.5), along with specific temperature (-20°C to 50°C) and pressure conditions. These parameter changes enable the production of middle distillate with sulfur content below 10 ppm and olefin content below 3 wt%, achieving both high manufacturing precision and oxidation stability.
2Manufacturing precision
If additional hydrofinishing steps are implemented to reduce sulfur and olefin content, then product quality improves, but process complexity and production cost increase
Solution Approach 1:
The patent extracts and eliminates the need for additional hydrofinishing steps by implementing a novel alkylation process using acidic ionic liquid catalysts that directly produce middle distillate with sufficiently low sulfur and olefin content. The process achieves sulfur content below 10 ppm and olefin content below 3 wt% through the alkylation reaction itself, without requiring subsequent hydrofinishing units, thereby reducing device complexity while maintaining high manufacturing precision.
3Productivity
If conventional catalysts are used in alkylation, then process simplicity is maintained, but product yield and quality are insufficient
Solution Approach 1:
The patent employs composite acidic ionic liquid catalysts formed by combining Lewis acidic compounds (such as AlCl3, FeCl3, ZnCl2) with Bronsted acidic ionic liquids or halide-containing additives (HCl, HBr, HI). This composite catalyst system produces middle distillate with yields at least 1.3 times the amount of olefin reacted, while maintaining a relatively simple liquid-phase process without requiring complex solid catalyst bed systems.
Data Source
AI summary
An alkylation process, comprising providing an isoparaffin feed that comprises at least 20 wt % C5+, providing a hydrocarbon stream that comprises at least 20 wt % C5+ olefins, and contacting the isoparaffin feed and the hydrocarbon stream with an ionic liquid catalyst under alkylation conditions wherein a middle distillate is produced. The middle distillate has less than 10 ppm sulfur and less than 3 wt % olefin. An alkylation process comprising contacting a naphtha with a low RON and a hydrocarbon stream comprising C5 olefins to an ionic liquid alkylation reactor under alkylation conditions, and recovering a middle distillate comprising less than 3 wt % olefin. A refinery process, comprising a hydrocracker that produces C5+ isoparaffin, a FC cracker that produces a hydrocarbon stream comprising a C5+ olefin, and an ionic liquid alkylation reactor that produces a high yield of middle distillate.