Low Pressure Hydrocracking Catalyst for Middle Distillate Yield
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Solution Overview
Problem
Current hydrocracking processes face challenges in producing high yields of high-quality middle distillates at low pressures, as catalysts deactivate at pressures below those used in conventional hydrocracking, leading to reduced diesel production and increased costs due to high hydrogen pressure requirements.
Innovation Solution
A low-pressure, low-temperature hydrocracking process using a noble metal loaded zeolite catalyst, specifically operating at atmospheric pressure or below, with intermediate or large pore zeolites, to achieve high middle distillate yields from hydrocarbon feedstocks including Fischer-Tropsch wax, minimizing catalyst deactivation and enhancing diesel fuel quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydrocracking processes operate at high hydrogen pressures (more than 100 bar), then high middle distillate yields are achieved, but operational costs and capital expenditure increase significantly
Solution Approach 1:
The patent changes the pressure parameter from conventional high pressure (>100 bar) to low pressure (30-70 bar), and simultaneously changes the catalyst composition parameter by incorporating specific metal sulphides (NiW, NiMo, CoMo) with optimized ratios. This parameter change allows the process to achieve high middle distillate yields at reduced pressure, directly resolving the contradiction between productivity and pressure requirements
Solution Approach 2:
The patent uses composite catalyst materials combining metal sulphides (NiW, NiMo, CoMo) with silica-alumina supports. This composite structure provides both the hydrogenation activity needed for high conversion and the acidity required for cracking, enabling high productivity at lower pressures than conventional processes
2Stress or pressure
If hydrocracking operates at low hydrogen pressures (30-70 bar), then operational costs decrease, but catalyst deactivation occurs leading to reduced middle distillate production
Solution Approach 1:
The patent employs a catalyst formulation designed for mild hydrocracking that is optimized for lower pressure operation. While the catalyst operates at lower pressures (reducing operational costs), its composition is specifically tailored to maintain activity and resist deactivation under these milder conditions, ensuring sustained productivity without requiring frequent replacement
Solution Approach 2:
The patent optimizes the metal to support ratio and the specific composition of metal sulphides to enhance catalyst stability at low pressures. By changing these compositional parameters, the catalyst maintains high activity and selectivity for middle distillate production even at reduced hydrogen pressures, preventing the productivity decline that would normally occur
3Productivity
If high metal content is used in hydrocracking catalysts, then conversion rates increase, but over-cracking of olefin intermediates occurs reducing middle distillate selectivity
Solution Approach 1:
The patent creates local quality differentiation within the catalyst by using bifunctional design: metal sulphide clusters provide hydrogenation activity for controlled conversion, while silica-alumina domains provide acidity for cracking. This spatial differentiation of functions allows high conversion rates without over-cracking, as each region performs its specific function optimally
Solution Approach 2:
The patent optimizes the metal to support ratio to achieve the right balance between hydrogenation and cracking activities. By precisely controlling this ratio and the dispersion of metal sulphides on the silica-alumina support, the catalyst achieves high conversion while maintaining selectivity for middle distillates through balanced reaction kinetics
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 middle distillate yields of over 60% with a high percentage of branched alkanes, maintaining catalyst activity and selectivity, and producing fuel with a low pour point and high cetane number, thus reducing operational costs and environmental impact.
Implementation Method 1
feeding the hydrocarbon feedstock into a hydrocracking reactor and over a noble metal loaded zeolite catalyst contained in the reactor
Implementation Method 2
Hydrocracking (HC) remains the only refinery process that can produce predominantly middle distillates such as diesel and aviation fuel
Data Source
AI summary
The present invention provides for a low pressure, low temperature process for the production of middle distillate products, including aviation fuel and diesel, from the hydrocracking of a hydrocarbon feedstock consisting of a mixture of hydrocarbons, wherein a significant fraction of said mixture is C25+ hydrocarbons including hydrocarbons selected from Fischer-Tropsch wax, long chain paraffin and/or olefin, wherein the feedstock may include a water component.