Self-sulfiding Guard Reactor Catalyst for Tar Conversion
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Solution Overview
Problem
Current hydroprocessing methods for pyrolysis tars are energy-intensive, material-intensive, and time-consuming, with discontinuous sulfiding processes leading to inefficient production of hydroconverted products and increased reactor fouling.
Innovation Solution
A method involving thermal treatment of pyrolysis tar to reduce reactivity, blending with a utility fluid to create a lower viscosity stream, and hydroprocessing in a guard reactor without prior sulfiding of catalysts, under mild conditions, which activates catalysts using sulfur-containing compounds from the tar itself.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional sulfiding process is performed before hydroprocessing, then catalyst activity is improved, but processing time and energy consumption increase
Solution Approach 1:
The patent performs thermal treatment of the pyrolysis tar feedstock before hydroprocessing to pre-activate the catalyst and reduce fouling potential. This preliminary action prepares the feedstock in advance, allowing the hydroprocessing to proceed more efficiently without requiring extended sulfiding time.
Solution Approach 2:
The patent eliminates the discontinuous sulfiding process by integrating catalyst activation directly into the hydroprocessing operation. The catalyst is activated in-situ during the hydroprocessing stage itself, allowing continuous operation without separate sulfiding and cleaning phases, thereby reducing total processing time.
2Reliability
If a conventional sulfiding process is performed before hydroprocessing, then catalyst activation is improved, but energy consumption increases
Solution Approach 1:
The patent combines the catalyst activation function with the hydroprocessing operation. The thermal treatment and hydroprocessing stages are integrated such that catalyst activation occurs simultaneously with or immediately before hydroprocessing begins, eliminating the need for separate energy-intensive sulfiding operations.
Solution Approach 2:
The pyrolysis tar feedstock itself serves as the sulfur source for catalyst activation during hydroprocessing. The sulfur-containing compounds naturally present in the tar activate the catalyst in-situ, eliminating the need for external sulfiding agents and the energy required to deliver and remove them.
3Object-affected harmful factors
If thermal treatment is applied to reduce tar reactivity, then reactor fouling is reduced, but processing time increases
Solution Approach 1:
The patent applies thermal treatment at controlled temperatures to modify the chemical parameters of the pyrolysis tar, specifically reducing the reactivity of unsaturated hydrocarbons and radicals. This parameter change decreases fouling tendency while maintaining process efficiency through optimized treatment conditions.
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 reduces energy consumption, material use, and processing time while maintaining or improving reactor fouling resistance, enabling efficient production of low-sulfur fuel oil and other hydroprocessing products.
Implementation Method 1
The hydroprocessing catalysts can include transition metals and the catalysts are sulfided by a sulfiding process to activate the catalyst(s) into an active form and to promote hydroprocessing of the pyrolysis tar upon contact with the sulfided catalyst(s)
Implementation Method 2
A sulfiding process typically includes flowing a catalyst activator, such as a sulfur-containing compound (such as dimethyldisulfide (DMDS)), from an activator source into each of the hydroprocessing reactors
Implementation Method 3
Pyrolysis processes, such as steam cracking, are utilized for converting saturated hydrocarbons to higher-value products such as light olefins, e.g., ethylene and propylene
Data Source
AI summary
The present disclosure provides methods for hydroprocessing of heavy oils, such as pyrolysis tars. For example, a process for preparing a liquid hydrocarbon product includes providing a first process stream comprising a reduced reactivity tar, and blending the first process stream with a utility fluid to produce a second process stream comprising solids and a reduced reactivity, lower viscosity tar. The method can includes introducing the second process stream into a guard reactor without sulfiding the guard reactor catalyst(s) prior to introducing the second process stream into the guard reactor. The method includes hydroprocessing the second process stream in the guard reactor under mild hydroprocessing conditions to produce a third process stream. The method includes hydroprocessing the third process stream to produce a fourth process stream having a bromine number (BN) lower than 12 and comprising the liquid hydrocarbon product and the utility fluid.