Multi-Stage Cyclohexane Oxidation Reactor Temperature Control
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Solution Overview
Problem
The existing processes for oxidizing saturated hydrocarbons like cyclohexane to produce alkyl hydroperoxide face challenges in maintaining selectivity and controlling reaction temperature, leading to reduced efficiency and increased consumption of cyclohexane due to uncontrolled heat and high concentrations of oxidized products.
Innovation Solution
The process involves feeding saturated hydrocarbons at controlled temperatures in multiple stages, recovering and recycling gaseous phases to maintain optimal temperature ranges and reduce oxidized product concentrations, thereby improving selectivity and reducing cyclohexane consumption by recycling condensates directly without intermediate purification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the oxidation reaction is carried out in a single reactor with high conversion, then productivity is improved, but selectivity for hydroperoxide deteriorates due to uncontrolled temperature rise and high concentration of oxidized products
Solution Approach 1:
The oxidation process is divided into multiple reactors in series, each operating at low conversion (10-30%). This segmentation allows better temperature control and maintains low oxidized product concentrations in each reactor, preserving hydroperoxide selectivity while achieving high overall productivity through cumulative conversion across the reactor train.
2Productivity
If the concentration of oxidized products is increased to improve productivity, then the reaction rate increases, but selectivity deteriorates due to accelerated deperoxidation
Solution Approach 1:
By distributing the total conversion across multiple reactors, each reactor maintains low oxidized product concentrations that prevent deperoxidation reactions. The overall productivity is achieved through the series arrangement, not by concentrating oxidized products in a single reactor.
Solution Approach 2:
The process dynamically balances reaction rate and selectivity by controlling the concentration of oxidized products at optimal levels in each reactor. Fresh hydrocarbon is continuously fed to maintain low oxidized product concentrations, dynamically preventing deperoxidation while sustaining productive reaction rates.
3Loss of substance
If recycling of gaseous phase is implemented to improve economy, then unoxidized hydrocarbon is recovered, but the recycling process may disturb the operating conditions and selectivity in the reactor
Solution Approach 1:
The gaseous phase containing unoxidized hydrocarbon and oxidized products is extracted and separated from the liquid reaction phase. The unoxidized hydrocarbon is then recycled to the reactor feed, while the oxidized products remain in the liquid phase. This separation prevents disturbance of reactor operating conditions while recovering valuable unreacted hydrocarbon.
4Manufacturing precision
If multiple reactors in series are used to control temperature and selectivity, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The oxidation process is segmented into multiple reactors in series, each operating at low conversion (10-30%). This segmentation allows better temperature control and maintains low oxidized product concentrations in each reactor, preserving hydroperoxide selectivity while achieving high overall productivity through cumulative conversion across the reactor train.
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 enhances the selectivity and efficiency of alkyl hydroperoxide production by maintaining reaction temperatures within optimal ranges, reducing the quantity of recycled hydrocarbon, and minimizing the concentration of heavy products, resulting in lower cyclohexane consumption per tonne of cyclohexanol and cyclohexanone produced.
Implementation Method 1
The present invention relates to a process for the oxidation by oxygen of saturated cyclic hydrocarbons such as cyclohexane for the production of alkyl hydroperoxide
Implementation Method 2
at least in the last stage, the reaction medium is cooled to maintain the temperature of the reaction medium at a level lower than or equal to that of the first stage
Implementation Method 3
the gaseous phases forming the headspace in each reaction stage are recovered and at least partially condensed
Data Source
AI summary
The present invention relates to a method for oxidizing saturated hydrocarbons with oxygen, preferably saturated cyclic hydrocarbons such as cyclohexane, in order to produce alkyl hydroperoxide. The invention relates specifically to a method for oxidizing saturated hydrocarbons with oxygen, the oxidation being carried out in a plurality of consecutive steps in order to control the rate of the hydrocarbon oxidation reaction and to obtain a high degree of alkyl hydroperoxide selectivity. The method of the invention relates to the method for condensing the oxidation gases recovered in each oxidation reactor and the recycling thereof in the oxidation reactors. According to the recycling method of the invention, the selectivity of the ketone and alcohol reaction is improved, as well as the economy of the method, by a decrease in "cold" hydrocarbons supplied to certain reactors in order to control the temperature.