Multi-tubular Reactor Catalyst Swap for Phenol Hydrogenation
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Solution Overview
Problem
The high investment costs associated with switching to a new plant for producing a mixture of cyclohexanone and cyclohexanol through the hydrogenation of phenol, due to the complexity and expense of reactors suitable for phenol hydrogenation, pose a significant drawback for current producers using the benzene hydrogenation followed by oxidation process.
Innovation Solution
A continuous process for producing cyclohexanone and cyclohexanol by hydrogenating phenol in an industrial-scale chemical plant equipped with a multi-tubular reactor originally designed for benzene hydrogenation, where the benzene hydrogenation catalyst is replaced with a phenol hydrogenation catalyst, allowing for the reuse of existing reactor infrastructure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a new plant with specialized reactors is built for phenol hydrogenation, then production capability is improved, but investment costs increase significantly
Solution Approach 1:
The patent applies universality by enabling existing benzene hydrogenation reactors to perform phenol hydrogenation through catalyst replacement. The reactor infrastructure designed for benzene hydrogenation is made multi-functional by simply replacing the catalyst from benzene hydrogenation catalyst to phenol hydrogenation catalyst, allowing the same physical reactor to serve dual purposes and eliminating the need for specialized new reactor construction.
Solution Approach 2:
The patent applies parameter changes by altering the chemical nature of the catalyst rather than the physical reactor structure. By changing the catalyst type (from benzene hydrogenation catalyst to phenol hydrogenation catalyst) while keeping the reactor infrastructure unchanged, the process achieves phenol hydrogenation capability without the high investment costs associated with building new specialized equipment.
2Ease of manufacture
If benzene hydrogenation followed by oxidation is used, then production process is established, but safety risks increase due to cyclohexane-oxygen mixtures
Solution Approach 1:
The patent applies this principle by replacing the hazardous oxidation step with a safer direct phenol hydrogenation process. Instead of producing cyclohexane and then oxidizing it (which creates explosive cyclohexane-oxygen mixtures), the process directly hydrogenates phenol to cyclohexanone and cyclohexanol, converting a potentially harmful multi-step process into a safer single-step process that avoids the formation of explosive intermediate mixtures.
3Productivity
If benzene hydrogenation followed by oxidation is used, then cyclohexanone production is achieved, but carbon efficiency decreases and by-products increase
Solution Approach 1:
The patent applies this principle by extracting and eliminating the oxidation step from the production process. By removing the oxidation step that converts cyclohexane to cyclohexanone (which generates by-products and carbon loss), the process directly hydrogenates phenol to the desired products, thereby extracting the harmful intermediate steps and achieving better carbon efficiency.
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 investment costs, enhances carbon efficiency, minimizes energy consumption, and decreases by-product formation, while eliminating the safety risks associated with cyclohexane-oxygen mixtures, thereby offering a more economical and safer production method.
Implementation Method 1
Heat of reaction is removed by indirect cooling with a coolant
Implementation Method 2
indirect cooling with a liquid in a jacketed reactor
Implementation Method 3
catalytic reduction of phenol with hydrogen, for example using a palladium-comprising heterogeneous catalyst
Implementation Method 4
hydrogenation of phenol
Implementation Method 5
the coolant is a liquid, which is optionally evaporated. In case liquid water is applied as coolant then steam is optionally obtained by evaporation of liquid water within the shell of the reactor
Data Source
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AI summary
A continuous process for the production of a mixture comprising cyclohexanone and cyclohexanol by hydrogenation of phenol, which process is performed in a chemical plant comprising a multi-tubular reactor characterised in that said multi-tubular reactor has been used for the hydrogenation of benzene; a chemical plant suitable for the hydrogenation of phenol comprising a multi-tubular reactor; cyclohexanone prepared in a chemical plant comprising a multi-tubular reactor; and a process for constructing such a plant.