Phenol Hydrogenation Dilution Gas Recycle System
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Solution Overview
Problem
Current methods for generating cyclohexanone through phenol hydrogenation face challenges such as low conversion rates, high energy consumption, and complex separation processes, with existing methods requiring multiple distillation steps and inefficient use of residual gases with low calorific value.
Innovation Solution
A method involving the use of a flammable gas to dilute hydrogen gas concentration during phenol hydrogenation, utilizing a reactor, separator, compressor, and burning furnace to recycle and adjust gas concentrations, and utilize residual gases as auxiliary fuel, while maintaining high conversion rates and selectivity for cyclohexanone production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple distillation processes and purifying steps are added to improve product selectivity, then cyclohexanone selectivity is improved, but device complexity and energy consumption increase
Solution Approach 1:
The patent modifies reaction parameters including hydrogen gas concentration (30-80 mole%), temperature (150-250°C), and pressure (0-22 psig) to optimize the hydrogenation reaction, achieving high selectivity without complex purification. The use of specific catalysts (Group 10 metals) and controlled reaction conditions enables selective cyclohexanone production
Solution Approach 2:
The patent introduces a flammable gas as an intermediary substance to dilute the hydrogen gas concentration in the reaction mixture. This intermediary enables better control over reaction selectivity and reduces the formation of byproducts, thereby reducing the need for complex distillation and purification steps
2Productivity
If nitrogen gas is added to raise throughput, then productivity is improved, but residual gas calorific value decreases
Solution Approach 1:
The patent changes the dilution gas from nitrogen to a flammable gas, fundamentally altering the energy characteristics of the residual gas stream while maintaining the throughput enhancement benefit
Solution Approach 2:
The patent converts what would be wasted residual gas into a valuable energy resource by using a flammable gas for dilution. The residual gas containing unreacted hydrogen and flammable gas can be burned to generate thermal energy, transforming a potential waste stream into an energy source that can offset process energy requirements
3Productivity
If hydrogen gas concentration is increased to improve conversion rate, then cyclohexanone conversion rate is improved, but energy consumption and safety risks increase
Solution Approach 1:
The patent optimizes hydrogen gas concentration to a specific range (30-80 mole%) rather than using high concentrations, achieving effective conversion while reducing energy consumption and safety risks. This parameter optimization is combined with temperature and pressure control to maintain high reaction efficiency
Solution Approach 2:
The flammable gas acts as an intermediary that enables effective hydrogenation reaction without requiring high hydrogen concentrations. The diluted hydrogen gas still achieves good conversion rates while reducing the energy input required and lowering safety hazards associated with high-concentration hydrogen handling
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 increases throughput, reduces energy consumption, and enhances the caloric value of residual gases, allowing for more efficient cyclohexanone production with improved selectivity and utilization of by-products as fuel, thus addressing the inefficiencies of existing methods.
Implementation Method 1
hydrogenating phenol in the presence of hydrogen gas, a flammable gas for dilution, and a catalyst comprising at least one Group 10 metal
Implementation Method 2
a catalyst comprising at least one Group 10 metal
Implementation Method 3
introducing an additional flammable gas to dilute a hydrogen gas concentration for generating cyclohexanone by hydrogenating phenol
Implementation Method 4
a compressor connected to the separator and the reactor and configured to recycle at least a part of the residual gases separated from the separator back to the reactor to adjust the hydrogen gas concentration therein
Implementation Method 5
a burning furnace connected to the separator and configured to burn a part of the residual gases separated from the separator to generate thermal energy
Data Source
AI summary
A method of preparing cyclohexanone by hydrogenating phenol is provided. The method includes a step of introducing an additional flammable gas to dilute hydrogen gas concentration, so as to increase the throughput and decrease energy consumption. Further, the discharged residual gases from the hydrogenation of phenol have a calorific value. Also provided is a system for generating cyclohexanone by hydrogenating phenol.