Mixed Solvent Deasphalting for High Quality Coke
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Solution Overview
Problem
Conventional methods for producing high quality coke, such as high severity hydrotreating and hydrocracking, are costly due to their high pressure requirements and inefficiencies in processing residual oil with significant asphalt and impurities, which reduces the yield of high quality coke.
Innovation Solution
A process using mixed solvent deasphalting upstream of a delayed coker, comprising a solvent mixture of 95-97% paraffinic solvent and 3-5% aromatic solvent, which replaces or complements hydrotreating to produce high quality green coke while reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high severity hydrotreating and hydrocracking are used to purify residual oil, then the quality of green coke is improved, but the production cost increases significantly due to high pressure requirements
Solution Approach 1:
The patent extracts and removes asphalt and impurities from residual oil using solvent deasphalting upstream of the delayed coker, eliminating the need for expensive high severity hydrotreating and hydrocracking processes while maintaining the quality of green coke produced
Solution Approach 2:
The patent changes the processing parameters by operating the solvent deasphalting unit at moderate conditions and optimizing the delayed coker operation to achieve high quality coke without requiring the extreme pressure conditions of high severity hydrotreating
2Manufacturing precision
If conventional hydrotreating is used to process residual oil with significant asphalt and impurities, then the purity of feedstock is improved, but the yield of high quality coke decreases
Solution Approach 1:
The patent introduces a solvent deasphalting unit as an intermediary process between residual oil and the delayed coker, using solvents to selectively separate asphalt and impurities, thereby preserving more valuable hydrocarbon components that would otherwise be lost in conventional hydrotreating
3Manufacturing precision
If high pressure hydrotreating is applied to residual oil, then the removal of impurities is improved, but the operational cost increases
Solution Approach 1:
The patent replaces the mechanical high pressure hydrotreating system with a chemical solvent-based deasphalting system that operates at moderate pressures, using solvent-impurity interactions to achieve impurity removal without requiring extreme pressure conditions
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 increases the yield of deasphalted oil while maintaining its quality, enabling the production of high quality coke at lower operational costs by optimizing the solvent mixture composition and processing conditions in the solvent deasphalting and delayed coking units.
Implementation Method 1
a solvent deasphalting step wherein a solvent mixture comprising a polar and a non-polar solvent is used
Implementation Method 2
introducing residual oil and a solvent mixture into a mixing vessel to produce a feed mixture
Implementation Method 3
the hot feed then goes to a coke drum maintained at coking conditions where the feed is cracked to form light products
Data Source
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AI summary
Process embodiments for producing green coke from residual oil comprise introducing residual oil and a solvent mixture into a mixing vessel to produce a feed mixture, the solvent mixture comprising at least one paraffinic solvent with a carbon number from 3 to 8 and at least one aromatic solvent, where the solvent mixture comprises from 0.1 to 10 % by volume of aromatic solvent and 90 to 99.9% by volume of paraffinic solvent, passing the feed mixture to a solvent deasphalting unit to produce a deasphalted oil (DAO) fraction and an asphalt fraction, and passing the DAO fraction to a delayed coker to produce the green coke and a delayed coker effluent.