Deep Desulphurization Catalyst Without Pre-Sulphurization
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Solution Overview
Problem
Current desulphurization processes for hydrocarbon feedstocks with low sulphur content (<50 ppm) require costly and time-consuming pre-sulphurization steps, as the existing catalysts in oxide form are not active enough to efficiently remove the last ppm of sulphur, especially when the sulphur content is sterically hindered in polycyclic molecules.
Innovation Solution
A process using cobalt or nickel oxide and molybdenum trioxide catalysts in oxide form, supported on alumina or silica-alumina, is employed without pre-sulphurization, where the catalysts are dried with a hydrogen flow and directly contacted with the hydrocarbon feedstock at moderate temperatures and pressures, allowing deep desulphurization to below 5 ppm sulphur content without intermediate steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pre-sulphurization step is added to activate the catalyst, then desulphurization efficiency is improved, but process complexity and time consumption increase
Solution Approach 1:
The catalyst is pre-sulphurized during the manufacturing process before being put into service, rather than requiring a separate pre-sulphurization step in the processing unit. This preliminary action is performed once during catalyst preparation, eliminating the need for recurring pre-treatment operations and reducing overall process complexity while maintaining high desulphurization efficiency
Solution Approach 2:
The catalyst is designed to be self-activating upon contact with the hydrocarbon feedstock containing low sulphur content. The catalyst automatically adjusts its state through the inherent sulphur present in the feedstock, eliminating the need for external pre-sulphurization steps and reducing process complexity
2Manufacturing precision
If pre-sulphurization step is added to activate the catalyst, then desulphurization efficiency is improved, but processing time increases
Solution Approach 1:
The catalyst activation through sulphurization is performed in advance during the catalyst manufacturing process, before the catalyst is installed in the processing unit. This preliminary action eliminates the need for time-consuming pre-sulphurization steps during normal operation, thereby reducing overall processing time while ensuring the catalyst is fully active from the start
Solution Approach 2:
The catalyst is designed to activate automatically upon contact with the hydrocarbon feedstock, using the inherent sulphur content to reach its active state. This self-service mechanism eliminates the need for separate activation steps, significantly reducing processing time while achieving full desulphurization efficiency
3Ease of operation
If oxide form catalyst is used without pre-sulphurization, then process simplicity is improved, but desulphurization efficiency deteriorates
Solution Approach 1:
The catalyst formulation is modified by adjusting the oxidation state and composition of metal components (such as using partially reduced metal oxides or specific ratios of metal phases) to enhance its intrinsic activity towards desulphurization. This parameter change allows the catalyst to achieve high desulphurization efficiency in the oxide form without requiring pre-sulphurization, thus maintaining process simplicity
Solution Approach 2:
The catalyst is designed as a composite material combining metal oxides with specific support materials or promoters that enhance its desulphurization activity. This composite structure provides synergistic effects that improve catalytic performance, enabling the oxide form catalyst to achieve high desulphurization efficiency without pre-sulphurization treatment
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 extends the catalyst's lifespan, eliminates the need for pre-sulphurization, and achieves deep desulphurization efficiently, maintaining low sulphur levels in the hydrocarbon fluid, even at reduced pressures, making it suitable for integration with existing hydrotreating units.
Implementation Method 1
A process using cobalt or nickel oxide and molybdenum trioxide catalysts in oxide form, supported on alumina or silica-alumina, is employed without pre-sulphurization
Implementation Method 2
where the catalysts are dried with a hydrogen flow and directly contacted with the hydrocarbon feedstock
Data Source
Figure 1
AI summary
The invention pertains to a process for deep desulphurization of low sulphur content feedstock comprising the steps of providing a low sulphur content hydrocarbon feedstock and contacting said hydrocarbon feedstock with a cobalt-molybdenum desulphurizing system or a nickel-molybdenum desulphurizing system in an oxide form in order to obtain a very low sulphur product comprising less than 5 ppm by weight sulphur.