Selective Deasphalting Solvent System for Heavy Hydrocarbon Conversion
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Solution Overview
Problem
Conventional deasphalting processes face limitations in yield and selectivity for deasphalted oil, leading to reduced conversion rates and increased shutdowns due to refractory molecular structures in hydroconversion units, which restrict the operability and profitability of heavy load hydroconversion processes.
Innovation Solution
A selective deasphalting process using a mixture of polar and apolar solvents under subcritical conditions to separate asphalt and deasphalted oil fractions, followed by hydroconversion in a three-phase reactor with a catalyst, optimizing solvent ratios and conditions to enhance yield and reduce sediment formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional deasphalting is used to remove refractory structures, then sediment formation is reduced, but the yield of deasphalted oil decreases and selectivity is low
Solution Approach 1:
The patent applies parameter changes by modifying the solvent system from conventional single solvents to a dual solvent system comprising polar and non-polar solvents. This changes the extraction parameters to achieve both high deasphalted oil yield and low sediment formation, resolving the contradiction between quantity and quality of separation
Solution Approach 2:
The invention uses a composite solvent system combining polar and non-polar solvents in specific proportions. This composite approach enables selective extraction that maximizes deasphalted oil recovery while effectively removing refractory structures, simultaneously improving both yield and sediment reduction
2Reliability
If gentler operating conditions are used in hydroconversion units, then equipment shutdowns are reduced, but the conversion rate is limited
Solution Approach 1:
The patent implements preliminary action by performing selective deasphalting before hydroconversion to remove refractory molecular structures that cause sediment formation. This pretreatment enables the hydroconversion unit to operate at higher conversion rates without frequent shutdowns, as the problematic structures are removed in advance
Solution Approach 2:
The invention extracts and removes the harmful refractory structures (asphaltenes and resins) from the feedstock before hydroconversion. This extraction of problematic components allows the hydroconversion unit to maintain high productivity without sacrificing reliability
3Reliability
If conventional deasphalting is used, then some asphalt is removed, but over-quality deasphalted oil is extracted with significant usable molecular structures remaining in the asphalt fraction
Solution Approach 1:
The patent applies local quality by using a dual solvent system with different polarities to achieve selective extraction. The polar solvent selectively targets asphaltene structures while the non-polar solvent interacts with resin structures, enabling differentiated separation that preserves usable molecular structures in the deasphalted oil fraction
Data Source
AI summary
The invention relates to a process for converting a heavy hydrocarbon feedstock comprising the following steps: a) at least one step of selective deasphalting of the heavy hydrocarbon feedstock by liquid/liquid extraction allowing the separation of at least one asphalt fraction, at least one deasphalted oil fraction, b) a step of hydroconversion of the deasphalted oil fraction in the presence of hydrogen in at least one three-phase reactor, under conditions allowing the obtaining of an effluent comprising a gaseous fraction containing predominantly the compounds H2 and H2S, and a liquid fraction with reduced content of Conradson carbon, metals, sulfur and nitrogen, c) a step of separating the effluent from step b) to obtain a gaseous fraction containing predominantly the compounds H2 and H2S and a liquid fraction with reduced content of Conradson carbon, metals, sulfur and nitrogen.