Ebullated Bed Hydroconversion Process Maximizing Gasoline Yield
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Solution Overview
Problem
Existing processes for converting heavy oil residues into gasoline suffer from low gas oil production yields due to the difficulty in upgrading vacuum distillates obtained from vacuum separation, which have polycondensed structures.
Innovation Solution
A process involving ebullated bed hydroconversion followed by hydrotreatment or hydrocracking, with recycling of unconverted vacuum gas oil fractions to maximize gasoline production, utilizing specific catalysts and operating conditions to enhance conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If vacuum separation is used to separate hydroconverted effluent, then separation into fractions is achieved, but the vacuum distillates obtained have polycondensed structures that are difficult to upgrade into oil base
Solution Approach 1:
The process segments the hydroconverted effluent into multiple fractions through vacuum separation: a first vacuum distillate fraction (lighter, easier to upgrade), a second vacuum distillate fraction (heavier, more difficult to upgrade), and a residual fraction. This segmentation allows different fractions to be treated differently - the first fraction is used for gasoline production while the second fraction is recycled back to the hydroconversion unit, optimizing the overall process efficiency and gasoline yield.
2Productivity
If conventional conversion processes are used, then conversion of heavy oil residue is achieved, but gas oil production yield is limited due to purge of vacuum distillates
Solution Approach 1:
Instead of discarding the second vacuum distillate fraction (which contains polycondensed structures difficult to upgrade), the process recycles it back to the hydroconversion unit. This recovery and recycling approach allows the heavy fraction to undergo further conversion to lighter, more valuable products, thereby reducing the purge quantity of difficult-to-upgrade vacuum distillates and increasing overall gas oil production yield.
Solution Approach 2:
The process implements continuous recycling of the second vacuum distillate fraction back to the hydroconversion unit, creating a continuous loop of useful action. This ensures that heavy fractions are continuously converted through multiple passes, maximizing the conversion efficiency and gas oil production yield while minimizing the need to purge difficult-to-upgrade vacuum distillates.
3Quantity of substance
If intense conversion is applied to maximize gasoline yield, then gasoline production is increased, but conversion efficiency and process complexity increase
Solution Approach 1:
The process incorporates feedback mechanisms where the second vacuum distillate fraction is recycled back to the hydroconversion unit based on its composition and properties. This feedback loop allows the system to automatically adjust and optimize the conversion process, maximizing gasoline production while managing process complexity through intelligent material flow control.
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 significantly increases gasoline production yields while minimizing the purge of vacuum distillates, achieving higher naphtha production compared to prior art methods.
Implementation Method 1
a) a first step for ebullated bed hydroconversion of the feed in the presence of hydrogen
Implementation Method 2
comprising at least one three-phase reactor containing at least one ebullated bed hydroconversion catalyst
Implementation Method 3
b) a step for separating at least a portion of the hydroconverted liquid effluent obtained from step a) into a gasoline fraction, a gas oil fraction, a vacuum gas oil fraction and an unconverted residual fraction
Implementation Method 4
c) i) either a step for hydrotreatment of at least a portion of the gas oil fraction and the vacuum gas oil fraction obtained from step b) in a reactor comprising at least one fixed bed hydrotreatment catalyst
Implementation Method 5
ii) or a first step for hydrocracking at least a portion of the gas oil fraction and the vacuum gas oil fraction obtained from step b) in a reactor comprising at least one fixed bed hydrocracking catalyst
Data Source
AI summary
A process for the intense conversion of a heavy hydrocarbon feed, comprising a) ebullated bed hydroconversion of the feed; b) separating at least a portion of hydroconverted liquid effluent obtained from a); c)i) either hydrotreatment of at least a portion of the gas oil fraction and of the vacuum gas oil fraction obtained from b), ii) or hydrocracking at least a portion of gas oil fraction and vacuum gas oil fraction obtained from b); d) fractionation of at least a portion of the effluent obtained from c)i) or c)ii); e) recycling at least a portion of unconverted vacuum gas oil fraction obtained from the fractionation d) to said first hydroconversion a); f) hydrocracking at least a portion of gas oil fraction obtained from fractionation d); g) recycling all or a portion of effluent obtained from f) to the fractionation d).