Hydrocracking Paraffinic Feedstock with Zeolite Beta Catalyst
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Solution Overview
Problem
The Fischer-Tropsch process produces paraffinic compounds with high melting points, making them unsuitable for direct use as liquid fuels or lubricants, and existing processes fail to effectively lower aromatics content and maximize the yield of intermediate products like waxy raffinate.
Innovation Solution
A process involving a catalyst with 0.005 to 5.0 wt% Group VIII noble metal on a carrier containing 0.1-15 wt% zeolite beta and at least 40 wt% amorphous silica-alumina, where the feedstock is contacted with hydrogen at 175-400°C and 20-100 bar pressure, followed by fractionation and recycling of heavy fractions to maximize intermediate product yield while minimizing overcracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydrocracking followed by fractionation and dewaxing is used, then the paraffinic feedstock can be processed, but the operating temperature must be high and the yield of intermediate products is reduced
Solution Approach 1:
The patent changes the operating parameters by using a specific catalyst composition (Group VIII noble metal on carrier with zeolite beta and amorphous silica-alumina) that enables effective hydrocracking at lower temperatures (175-400°C), thereby improving intermediate product yield while reducing energy consumption
Solution Approach 2:
The patent employs a composite catalyst material consisting of Group VIII noble metal supported on a carrier containing both zeolite beta (0.1-15 wt%) and amorphous silica-alumina (at least 40 wt%), which combines the advantages of different materials to achieve high activity and selectivity at lower operating temperatures
2Object-generated harmful factors
If conventional hydrocracking is used, then processing can be achieved, but the aromatics content in products remains high
Solution Approach 1:
The patent modifies the chemical environment by using a specific catalyst system that promotes hydrocracking reactions favoring lower aromatics content, changing the reaction pathway to reduce harmful aromatic byproducts without requiring additional complex process steps
Solution Approach 2:
The patent introduces a specific catalyst as an intermediary substance that mediates the hydrocracking reaction, guiding the transformation of paraffinic feedstock into products with reduced aromatics content while the catalyst itself remains unchanged and can be reused
3Productivity
If heavy fractions are not recycled, then the process is simpler, but the conversion of heavy fractions is incomplete and productivity is reduced
Solution Approach 1:
The patent implements a feedback mechanism by recycling heavy fractions back to the reaction zone inlet, allowing unreacted heavy components to undergo further conversion in subsequent passes, thereby improving overall conversion efficiency and productivity
Solution Approach 2:
The patent ensures continuous conversion of heavy fractions by recycling them back into the reaction system, maintaining the useful hydrocracking action on heavy components until they are fully converted, rather than allowing the process to terminate after a single pass
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 achieves a high conversion of heavy fractions with low operating temperatures, resulting in premium-quality products with low aromatic content, suitable for applications requiring low aromatics, and increases the yield of waxy raffinate or base-oil precursor fractions.
Implementation Method 1
contacted with hydrogen at a temperature in the range of 175 to 400° C. and a pressure in the range of 20 to 100 bar in the presence of a catalyst comprising 0.005 to 5.0 wt % of a Group VIII noble metal on a carrier, the carrier comprising 0.1-15 wt % of a zeolite beta and at least 40 wt % of an amorphous silica-alumina
Implementation Method 2
contacted with hydrogen at a temperature in the range of 175 to 400° C. and a pressure in the range of 20 to 100 bar
Implementation Method 3
subjecting the effluent from the reaction zone to a fractionation step to form at least a heavy fraction, an intermediate fraction, and a light fraction
Data Source
AI summary
The invention provides a process for converting a paraffinic feedstock comprising at least 50 wt % of compounds boiling above 370° C., a paraffin content of at least 60 wt %, an aromatics content below 1 wt %, a naphthenic content below 2 wt %, a nitrogen content below 0.1 wt %, and a sulphur content below 0.1 wt %, comprising: (a) reacting the feedstock with hydrogen at a temperature between 175 and 400° C. and a pressure between 20 and 100 bar using a catalyst comprising 0.005 to 5.0 wt % of a Group VIII noble metal on a carrier comprising 0.1-15 wt % zeolite beta and at least 40 wt % amorphous silica-alumina (b) withdrawing the effluent (c) subjecting the effluent to a fractionation step to form a heavy fraction, an intermediate fraction, and a light fraction; and (d) providing at least part of the heavy fraction to the reaction zone.