Reactivated Hydroprocessing Catalysts for Tailgas Sulfur Abatement
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Solution Overview
Problem
Spent catalysts from hydroprocessing processes are often discarded as hazardous waste, and there is a need for effective methods to reuse them in tailgas treatment to reduce environmental impact and economic costs.
Innovation Solution
Reactivating spent catalysts from hydrotreating processes by regeneration or rejuvenation, and resizing, reshaping, or reformulating them for use in tailgas treatment processes, where they can convert sulfur-containing species into hydrogen sulfide, thereby extending their useful life and reducing waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If spent catalysts are discarded as hazardous waste, then waste management is simplified, but environmental impact increases and economic value is lost
Solution Approach 1:
The patent applies the discarding and recovering principle by collecting spent hydrotreating catalysts that would normally be discarded as hazardous waste, and recovering their valuable metal components (Co, Ni, Mo, W) through a systematic process involving leaching, purification, and precipitation to create reusable catalyst products
Solution Approach 2:
The patent converts the harmful aspect of spent catalysts (hazardous waste requiring costly disposal) into a beneficial resource by extracting precious metals and reforming them into active catalysts for tailgas treatment, thereby transforming an environmental liability into an economic and environmental asset
2Loss of substance
If spent catalysts are reactivated and reused, then waste reduction is achieved, but additional processing steps are required
Solution Approach 1:
The patent creates a multi-functional processing system that handles multiple catalyst types (Co-Mo and Ni-Mo based catalysts) through a unified approach, using the same leaching, purification, and precipitation methodology for different metal compositions, thereby managing complexity through standardization
Solution Approach 2:
The patent employs self-service principles by using sodium hydroxide solution that serves dual purposes: as the leaching agent to extract metals from spent catalysts and as the precipitating agent to recover pure metal hydroxides, eliminating the need for separate reagent systems
3Productivity
If fresh catalysts are used for tailgas treatment, then treatment efficiency is maximized, but operational costs increase
Solution Approach 1:
The patent applies parameter changes by adjusting the chemical composition and physical form of recycled catalyst materials through controlled precipitation processes, creating products with optimized metal content and particle characteristics that match the performance requirements of tailgas treatment applications
Solution Approach 2:
The patent creates simplified copies of commercial catalysts by synthesizing new catalyst materials from recovered metals that replicate the active phase composition and structure of fresh catalysts, thereby achieving comparable performance at reduced cost without requiring the original expensive catalyst formulations
4Adaptability or versatility
If spent catalysts are stored before reactivation, then processing flexibility is improved, but storage costs and environmental risks increase
Solution Approach 1:
The patent implements preliminary action by establishing a continuous collection and processing system that treats spent catalysts promptly upon removal from service, rather than allowing long-term storage, thereby proactively preventing waste accumulation and associated environmental risks while maintaining processing flexibility
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
The reactivated catalysts demonstrate high performance in converting sulfur-containing species, achieving sulfur recovery efficiencies comparable to or exceeding those of fresh tailgas catalysts, while reducing waste generation and operational costs.
Implementation Method 1
contacting the gas stream with the reactivated catalyst in the presence of hydrogen (H2) converts the one or more sulfur-containing species to hydrogen sulfide (H2S)
Implementation Method 2
the activity of the catalyst decreases over time, due to the accumulation of carbon-containing deposits, referred to as coke, on the catalyst and/or by the presence of deactivating inorganic materials
Data Source
AI summary
Disclosed herein are methods, systems, and compositions for providing catalysts for tail gas clean up in sulfur recovery operations. Aspects of the disclosure involve obtaining catalyst that was used in a first process, which is not a tailgas treating process and then using the so-obtained catalyst in a tailgas treating process. For example, the catalyst may originally be a hydroprocessing catalyst. A beneficial aspect of the disclosed methods and systems is that the re-use of spent hydroprocessing catalyst reduces hazardous waste generation by operators from spent catalyst disposal. Ultimately, this helps reduce the environmental impact of the catalyst life cycle. The disclosed methods and systems also provide an economically attractive source of high-performance catalyst for tailgas treatment, which benefits the spent catalyst generator, the catalyst provider, and the catalyst consumer.