Two-Stage Dearsenification Process for Hydrocarbon Feed
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current dearsenification processes for hydrocarbon feeds are inefficient and require excessive amounts of catalysts, particularly when dealing with high flow rates, as arsenic can poison catalysts in transformation processes like selective hydrogenation and hydrodesulphurization.
Innovation Solution
A process involving two capture masses, one with metals from group VIB and VIII deposited on a support, and another with nickel in the sulphide form, is used to effectively remove arsenic from hydrocarbon feeds at high flow rates by contacting the feed with hydrogen at specific temperature and pressure conditions, allowing for efficient arsenic capture with reduced catalyst usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional dearsenification processes are used, then arsenic removal is achieved, but excessive amounts of catalysts are required and flow rates must be kept low
Solution Approach 1:
The invention divides the dearsenification process into two sequential stages using different capture masses: first a multi-metal capture mass (Mo, Co, Ni) to remove bulk arsenic, then a nickel sulphide capture mass to polish the effluent. This segmentation allows each stage to be optimized for its specific function, achieving high flow rates with reduced total catalyst usage compared to conventional single-stage processes
Solution Approach 2:
The invention changes the operational parameters significantly from conventional processes by operating at much higher hourly space velocities (4-50 h⁻¹ versus typically 1-2 h⁻¹). This parameter change is made possible by the optimized capture mass composition and the two-stage configuration, allowing productivity improvement without sacrificing removal efficiency
2Reliability
If arsenic is removed from lighter cuts, then catalyst poisoning in transformation processes is prevented, but volatile arsenic compounds remain in the feed
Solution Approach 1:
The invention introduces hydrogen as an intermediary substance that converts volatile arsenic compounds into forms that can be effectively captured. The hydrogen reacts with volatile arsenic species during the contact process, transforming them into captureable forms that are then removed by the capture masses, thus preventing catalyst poisoning while handling volatile compounds
3Productivity
If capture mass quantity is reduced, then process efficiency improves, but arsenic removal effectiveness may decrease
Solution Approach 1:
By segmenting the removal into two stages with different capture masses optimized for different arsenic loading levels, the system achieves high removal effectiveness with smaller total catalyst quantities. The first stage handles bulk removal at high capacity, the second stage provides polishing, together achieving superior efficiency versus single-stage systems
Solution Approach 2:
The invention uses composite capture mass formulations: the first capture mass contains multiple metals (Mo, Co, Ni) in specific ratios on a support, the second contains nickel sulphide. These composite materials provide synergistic effects that enhance arsenic capture capacity and efficiency per unit mass, allowing reduced total catalyst usage while maintaining or improving removal effectiveness
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 high arsenic removal efficiency with increased hourly space velocities, enabling the production of effluents with low arsenic content while minimizing catalyst usage, which is crucial for refinery operations.
Implementation Method 1
bringing the hydrocarbon feed and hydrogen into contact with a first capture mass comprising a support and at least one metal M1 from group VIB and at least two metals M2 and M3 from group VIII
Implementation Method 2
bringing the hydrocarbon feed and hydrogen into contact with a second capture mass in the sulphide form comprising a support and nickel
Data Source
AI summary
The invention of the current application is a process for eliminating arsenic from a hydrocarbon feed which is at least partially liquid, including steps a and b.Step a includes bringing the hydrocarbon feed and hydrogen into contact with a first capture mass including a support and at least one metal M1 from group VIB and at least two metals M2 and M3 from group VIII.Step b includes bringing the hydrocarbon feed and hydrogen into contact with a second capture mass in the sulphide form including a support and nickel, the quantity of nickel being at least 5% by weight of NiO with respect to the total weight of the second capture mass.Step a) is either carried out before step b) or carried out simultaneously with step b).