Hydrowax Hydrocracking Catalyst Layout for Heavy Fraction Retention
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Solution Overview
Problem
Existing processes for producing hydrowax result in a reduced ratio of heavy to light hydrowax, affecting the quality and yield of lubricating base oils, especially when higher conversion levels are required for heavier feeds.
Innovation Solution
A process involving hydrotreating and hydrocracking with specific catalysts, including a zeolitic component and amorphous silica-alumina, to enhance the ratio of heavy to light hydrowax production, using a hydrocarbonaceous feedstock with a high boiling point range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If higher conversion level is used in hydrocracker, then hydrowax quality is improved, but hydrowax yield becomes smaller
Solution Approach 1:
The hydrocracking process is divided into two distinct stages with different catalysts: first stage uses a conventional catalyst (NiMoP on alumina) for initial cracking, and second stage uses a dedicated catalyst (NiW on amorphous silica-alumina) for selective cracking. This segmentation allows each stage to perform a specific function, achieving high conversion while preserving heavy hydrowax fractions.
Solution Approach 2:
Different catalysts with specific local properties are used in each reaction zone. The first stage catalyst provides general hydrocracking activity, while the second stage catalyst with zeolitic component (at least 14 wt%) provides selective cracking activity. This local quality differentiation enables precise control over product distribution, maintaining both quality and yield.
2Manufacturing precision
If higher conversion level is used, then the ratio of heavy hydrowax over light hydrowax becomes smaller, but this reduces the ratio of heavy lubricating base oils over light lubricating base oils
Solution Approach 1:
The two-stage hydrocracking process segments the conversion function, with the second stage specifically designed to maintain heavy fraction integrity while achieving necessary conversion. This prevents excessive cracking that would reduce heavy hydrowax ratio.
Solution Approach 2:
The catalyst composition in the second stage is specifically modified with zeolitic component (at least 14 wt%) and amorphous silica-alumina in controlled ratios. These parameter changes in catalyst structure create selective cracking activity that preserves heavy hydrowax fractions while achieving high conversion levels.
3Quantity of substance
If heavier feed is used to hydrocracker, then heavier hydrowax is produced, but conversion level must be raised to maintain quality which reduces heavy to light hydrowax ratio
Solution Approach 1:
The two-stage process with different catalysts segments the handling of heavy feed. The first stage performs initial hydrotreating and cracking, while the second stage with zeolitic catalyst performs selective cracking that maintains heavy fraction quality without requiring excessive conversion.
Solution Approach 2:
The hydrocracking catalyst uses a composite structure combining crystalline zeolite (at least 14 wt%) with amorphous silica-alumina carrier. This composite material provides both the activity needed for heavy feed cracking and the selectivity to preserve heavy hydrowax fractions, eliminating the need to raise conversion excessively.
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
The process achieves a higher ratio of heavy to light hydrowax, improving the quality and yield of lubricating base oils and enabling effective production of lower olefins.
Implementation Method 1
hydrotreating the hydrocarbonaceous feedstock with a hydrotreating catalyst in the presence of a hydrogen-containing gas under hydrotreating conditions to obtain a hydrotreated product
Implementation Method 2
hydrocracking at least part of the hydrotreated product as obtained in step (b) with a hydrocracking catalyst in the presence of a hydrogen-containing gas under hydrocracking conditions to obtain a hydrocracked product
Data Source
AI summary
The invention provides a process for preparing a hydrowax comprising the steps of: (a) providing a hydrocarbonaceous feedstock which contains more than 4% by weight of hydrocarbons boiling in the range of from 550 to 800 °C; (b) hydrotreating the hydrocarbonaceous feedstock with a hydrotreating catalyst in the presence of a hydrogen- containing gas under hydrotreating conditions to obtain a hydrotreated product; (c) hydrocracking at least part of the hydrotreated product as obtained in step (b) with a hydrocracking catalyst in the presence of a hydrogen-containing gas under hydrocracking conditions to obtain a hydrocracked product, which hydrocracking catalyst contains a zeolitic component which is present in an amount of at least 14 wt%, based on the total weight of the hydrocracking catalyst, and wherein the volume ratio of the hydrotreating catalyst as used in step (b) and the hydrocracking catalyst is more than 1; and (d) recovering from the hydrocracked product as obtained in step (c) the hydrowax.