Hydrotreating Catalyst Sulfurization Startup Method
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current sulfurization methods for hydrotreatment and hydroconversion catalysts face challenges such as environmental risks, lengthy activation times, and high costs, particularly in large-scale units, with in-situ methods being economically viable but time-consuming, in-situ methods with added agents posing handling hazards, and ex-situ methods being costly and requiring careful air handling.
Innovation Solution
A process combining charge sulfurization without added sulfur compounds with a presulfurized and preactivated catalyst, where a hydrocarbon feed rich in sulfur is used to activate oxide catalysts in multiple beds, allowing for efficient sulfurization and activation under moderate conditions, reducing the need for external sulfur agents and simplifying the startup process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If in-situ sulfurization with added sulfur compounds (DMDS, TBPS) is used, then catalyst activation is achieved, but environmental risks and handling hazards increase
Solution Approach 1:
The process uses the sulfur naturally present in the hydrocarbon feedstock to sulfurize the catalyst, eliminating the need for external sulfurizing agents. The feedstock itself serves as the sulfur source, transforming the system from requiring external chemical inputs to using its own constituents for catalyst activation.
Solution Approach 2:
The method extracts and utilizes the sulfur already present in the hydrocarbon feedstock for catalyst sulfurization, rather than adding external sulfur compounds. This extraction approach removes the harmful external agents while retaining the necessary sulfur function.
2Object-affected harmful factors
If in-situ sulfurization without added sulfur compounds is used, then environmental risks are reduced, but activation time increases
Solution Approach 1:
The process modifies operational parameters including raising the temperature to 300-400°C and maintaining specific pressure conditions to accelerate the sulfurization reaction using feedstock sulfur. These parameter changes enable faster activation without external sulfurizing agents.
Solution Approach 2:
The sulfurization process proceeds through distinct stages: initial heating, sulfurization phase where H2S is generated and catalyst is activated, and transition to normal operation. This periodic progression through operational phases optimizes the activation timeline.
3Loss of time
If ex-situ sulfurization is used, then activation time is reduced, but costs increase and air handling requirements increase
Solution Approach 1:
The method combines the catalyst sulfurization step with the normal feedstock processing operation. The sulfurization occurs in-situ within the reactor using the actual process feedstock, merging two operations into one and eliminating separate sulfurization equipment and procedures.
Solution Approach 2:
The hydrocarbon feedstock serves multiple functions: it is both the material to be processed and the sulfurizing agent for catalyst activation. This multi-functionality eliminates the need for separate sulfurizing agents and reduces overall process complexity.
4Productivity
If high sulfur content feedstock is used for sulfurization, then sulfurization efficiency improves, but catalyst reduction risk increases
Solution Approach 1:
The process carefully controls temperature parameters, raising the reactor temperature to 300-400°C to promote sulfurization while maintaining conditions that prevent excessive catalyst reduction. The pressure and temperature profile is optimized to balance sulfurization efficiency with catalyst stability.
Solution Approach 2:
The system monitors the sulfurization progress through analysis of the effluent gas composition, particularly tracking H2S levels. This feedback enables adjustment of operational parameters to maintain optimal sulfurization while preventing catalyst reduction.
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 mitigates the disadvantages of existing methods by enabling faster startup, reducing environmental hazards, and lowering costs, while maintaining catalyst performance comparable to methods using external sulfurizing agents, with the presulfurized catalyst transforming sulfur molecules into hydrogen sulfide for effective catalyst activation.
Implementation Method 1
the presulfurized catalyst transforming sulfur molecules into hydrogen sulfide for effective catalyst activation
Implementation Method 2
the metals of these catalysts are only active for these reactions in sulfide form. It is therefore necessary to carry out sulfurization and activation of the catalyst prior to its use
Implementation Method 3
the first bed of presulfurized catalyst and preactivated reaches a temperature of at least 220°C
Data Source
AI summary
The invention describes a method for starting a hydroprocessing or hydroconversion unit carried out in the presence of hydrogen, in at least 2 catalytic beds, method in which at least one bed contains at least one presulphided and preactivated catalyst and at least one catalytic bed contains a catalyst of which the catalytic metals are in oxidised form, a so-called starting feedstock, which is a hydrocarbon cut containing at least 0.5% by weight of sulphur, free of olefinic compounds and containing no added sulphur compound, passes through a first catalytic bed containing said presulphided and preactivated catalyst, then passes through at least one catalytic bed containing a catalyst of which the catalytic metals are in oxidised form, and the first presulphided and preactivated catalyst bed reaches a temperature of at least 220°C.