Stacked CoMo NiMo Catalyst Bed for Mercaptan Sulfide Synthesis
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Solution Overview
Problem
Current methods fail to efficiently produce mercaptans and asymmetrical sulfides in a single reactor system with high yield and selectivity using supported cobalt-molybdenum (CoMo) and nickel-molybdenum (NiMo) catalysts.
Innovation Solution
A fixed bed reactor system with a stacked bed of CoMo and NiMo catalysts is used, where a first feed mixture of hydrogen sulfide and olefin is flowed through a CoMo catalyst layer followed by a NiMo catalyst layer to produce mercaptans, and a second feed mixture of symmetrical sulfides is flowed through both layers to produce asymmetrical sulfides, with carbon disulfide enhancing catalytic activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single reactor system is used to produce both mercaptans and asymmetrical sulfides, then device complexity is reduced, but manufacturing precision and selectivity deteriorate
Solution Approach 1:
The catalyst bed is segmented into two distinct layers: a first catalyst layer comprising CoMo catalyst for mercaptan synthesis, and a second catalyst layer comprising NiMo catalyst for asymmetrical sulfide synthesis. This segmentation allows each catalyst layer to independently perform its specific function, maintaining high selectivity while using a single reactor system.
Solution Approach 2:
Different regions of the catalyst bed are assigned different catalytic properties tailored to specific reactions. The CoMo-rich first layer provides optimal conditions for mercaptan formation from H2S and olefins, while the NiMo-rich second layer provides optimal conditions for asymmetrical sulfide formation from symmetrical sulfides. This local differentiation of catalyst composition maintains manufacturing precision.
2Manufacturing precision
If multiple reactors are used to maintain high yield and selectivity for both products, then manufacturing precision is maintained, but device complexity and loss of time increase
Solution Approach 1:
Two separate reactor systems that would traditionally be used for mercaptan and asymmetrical sulfide production are merged into a single reactor system. The stacked catalyst bed configuration allows both reactions to occur simultaneously in different layers, eliminating the need for separate reactors and reducing process time while maintaining high yields through optimized catalyst distribution.
Solution Approach 2:
The single reactor system is designed with multi-functional capability to perform both mercaptan synthesis and asymmetrical sulfide synthesis. The universal reactor vessel accommodates different catalyst layers that enable it to execute multiple chemical transformations in sequence, reducing the number of unit operations required.
3Manufacturing precision
If a stacked catalyst bed configuration is used, then manufacturing precision is maintained, but device complexity increases
Solution Approach 1:
The catalyst bed is divided into two functional segments or layers stacked vertically within the reactor. The first layer contains CoMo catalyst optimized for mercaptan production, while the second layer contains NiMo catalyst optimized for asymmetrical sulfide production. This segmentation enables high conversion efficiency for both reactions while using a relatively simple stacked configuration rather than complex multi-reactor arrangements.
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 allows for high conversion and yield of mercaptans and asymmetrical sulfides within a single reactor without the need for multiple reactors or catalyst changes, maintaining high efficiency and minimizing by-products.
Implementation Method 1
flowing a first feed mixture comprising hydrogen sulfide (H2S) and an olefin through a first catalyst layer of a fixed bed reactor comprising a supported CoMo catalyst, then through a second catalyst layer of the fixed bed reactor comprising a supported NiMo catalyst to produce a first reaction mixture comprising the mercaptan
Data Source
AI summary
The present disclosure generally relates to processes to produce a mercaptan and an asymmetrical sulfide utilize stacked bed catalyst systems containing CoMo and NiMo, and these processes demonstrate a synergistic reduction in the amount of ethylene, methyl mercaptan, ethyl mercaptan, and H2S in product mixtures. In aspects, the conversion of limiting reactants in the synthesis of asymmetrical sulfides unexpectedly remain high under increased flow rates through the catalyst bed, and under reduced temperatures and pressures. In further aspects, reactor systems configured for the independent synthesis of mercaptans and asymmetrical sulfides in a single fixed bed catalyst vessel are also disclosed as a simplification of existing reactor systems employing separate reactors for separate mercaptan and sulfide syntheses.