Low Pressure Naphtha Desulfurization Catalyst
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hydrodesulfurization processes for naphtha result in undesirable octane loss due to excessive hydrogenation of olefins and formation of mercaptans, which are challenging to control, especially when aiming for low sulfur levels in motor gasoline.
Innovation Solution
A low hydrogen partial pressure process using a hydrodesulfurization catalyst with a specific composition of Group VIII non-noble metals and Group VI metals on a refractory support, operated at high temperatures and high hydrogen treat gas rates, to selectively remove sulfur while minimizing olefin saturation and mercaptan formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional hydrodesulfurization is used to reduce sulfur levels, then sulfur removal is effective, but excessive olefin saturation occurs causing octane loss
Solution Approach 1:
The patent changes key process parameters including operating at lower hydrogen partial pressures (50-100 psig), higher temperatures (450-700°F), and higher hydrogen treat gas rates (200-5000 scf/b) to shift the reaction selectivity toward desulfurization while suppressing olefin hydrogenation
Solution Approach 2:
The patent employs composite catalyst formulations containing specific ratios of Group VIII non-noble metals (Fe, Co, Ni) combined with Group VI metals (Mo, W) on refractory supports, creating a catalyst with optimized duality for high desulfurization activity and selective olefin preservation
2Manufacturing precision
If conventional hydrodesulfurization is used to reduce sulfur levels, then sulfur removal is effective, but mercaptan formation increases
Solution Approach 1:
The patent operates at lower hydrogen partial pressures and higher temperatures to suppress the side reaction forming mercaptans while maintaining effective desulfurization, and uses high hydrogen treat gas rates to manage H2S concentrations that drive mercaptan formation
Solution Approach 2:
The patent manages the H2S produced during desulfurization by controlling its concentration through pressure and gas rate parameters, preventing H2S from reacting with olefins to form harmful mercaptans while maintaining the H2S necessary for catalyst function
3Manufacturing precision
If high hydrogen partial pressure is used to enhance desulfurization, then sulfur removal improves, but olefin saturation increases
Solution Approach 1:
The patent inverts the conventional approach by operating at low hydrogen partial pressures (50-100 psig), which suppresses olefin hydrogenation while maintaining desulfurization effectiveness through compensating increases in temperature and hydrogen treat gas rate
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 effectively reduces sulfur levels in naphtha while preserving olefins, thereby maintaining high octane ratings and minimizing mercaptan reversion, achieving deep desulfurization with reduced octane loss and mercaptan formation.
Implementation Method 1
The naphtha is reacted with hydrogen in the presence of a sulfided hydrodesulfurization (HDS) catalyst, which results in the formation of H2S and a sulfur-reduced naphtha
Implementation Method 2
The reaction zone is operated at temperatures from about 450° F. to about 700° F., a hydrogen partial pressure of about 50 to about 100 psig, and hydrogen treat gas rate of about 200 to about 5000 scf/b
Data Source
AI summary
A low hydrogen partial pressure process for desulfurizing naphtha in the presence of a hydrodesulfurization catalyst which catalyst is selective for suppressing hydrogenation of olefins and in the presence. This invention also relates to the use of optimum metals loading for achieving a high level of hydrodesulfurization with a low level of olefin saturation.