Residue Hydrocracking Sediment Control via Segmented Reactors
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Solution Overview
Problem
Ebullated bed hydrocracking processes face challenges with asphaltenic sediment formation downstream, leading to reduced conversion efficiency and product quality, as existing methods fail to effectively mitigate sediment deposition and improve product quality.
Innovation Solution
A process involving ebullated bed reactors, followed by a hydrotreating catalyst in an upflow reactor and a stripper, where hydrogen is used to contact the effluent with both residue and distillate hydrotreating catalysts, separating hydrocarbon fractions to reduce sediment formation and enhance product quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ebullated bed hydrocracking is used to increase conversion rates, then productivity is improved, but asphaltenic sediment formation increases downstream
Solution Approach 1:
The hydrocracking process is divided into two distinct stages: an ebullated bed reactor for high conversion and a fixed bed reactor specifically for sediment control. This segmentation allows each stage to be optimized for its specific function, with the fixed bed stage removing asphaltenic sediments generated by the high-conversion ebullated bed stage.
Solution Approach 2:
The fixed bed reactor acts as an intermediary stage between the ebullated bed reactor and downstream equipment. It provides a transition zone where asphaltenic sediments are controlled and removed, protecting downstream equipment while maintaining the high productivity benefits of ebullated bed hydrocracking.
2Productivity
If thermal cracking is increased to improve conversion, then productivity is improved, but product quality deteriorates
Solution Approach 1:
The process segments thermal cracking and catalytic conversion into separate stages. The ebullated bed reactor performs the harsh thermal cracking for high conversion, while the fixed bed reactor with its different catalyst provides controlled catalytic hydroconversion to improve product quality in the second stage.
Solution Approach 2:
The process changes operational parameters between stages: the ebullated bed reactor operates under conditions favorable for high conversion (higher temperature, shorter residence time), while the fixed bed reactor operates under conditions favorable for product quality (lower temperature, longer residence time, different catalyst type).
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 approach significantly reduces asphaltenic sediment formation and improves the quality of hydrocarbon products by increasing conversion rates and removing contaminants like sulfur and metals, thereby stabilizing the unconverted oil and enhancing downstream processing.
Implementation Method 1
contacting a residuum hydrocarbon fraction and hydrogen with a hydroconversion catalyst in a hydrocracking reaction zone to convert at least a portion of the residuum hydrocarbon fraction to lighter hydrocarbons
Implementation Method 2
contacting hydrogen and at least a portion of the effluent with a resid hydrotreating catalyst to remove contaminants like sulfur and metals
Implementation Method 3
contacting hydrogen and the effluent with a first resid hydrotreating catalyst in an upflow reactor; contact hydrogen and the heavy hydrocarbon fraction with a second resid hydrotreating catalyst
Implementation Method 4
separating the effluent to recover two or more hydrocarbon fractions comprising at least a heavy hydrocarbon fraction and a light hydrocarbon fraction
Implementation Method 5
a hydrocracking reaction zone comprising one or more ebullated bed reactors
Data Source
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AI summary
A process for upgrading residuum hydrocarbons and decreasing tendency of the resulting products toward asphaltenic sediment formation in downstream processes is disclosed. The process may include: contacting a residuum hydrocarbon fraction and hydrogen with a hydroconversion catalyst in a hydrocracking reaction zone to convert at least a portion of the residuum hydrocarbon fraction to lighter hydrocarbons; recovering an effluent from the hydrocracking reaction zone; contacting hydrogen and at least a portion of the effluent with a resid hydrotreating catalyst; and separating the effluent to recover two or more hydrocarbon fractions.