Multistage Cumene Oxidation Reactor Pressure Gradient
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Solution Overview
Problem
The existing processes for oxidizing cumene to cumene hydroperoxide face challenges such as the formation of unwanted side products like acetophenone, which are difficult to separate, and the need for complex parameter optimization, as well as inefficiencies in selectivity and safety due to the use of wet oxidation methods and pumps.
Innovation Solution
A process involving a series of 3-8 reactors with a lower pressure oxidizer as the first reactor and a higher pressure oxidizer as the last reactor, operating at specific pressure ranges, which allows for high CHP concentration and minimizes the formation of light and acidic impurities, and avoids the use of pumps and adsorbers, focusing on maximizing selectivity and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wet oxidation procedure is used, then oxidation can proceed in solution with aqueous carbonate, but additional steps are required to remove carbonate and neutralize the alkaline oxidized mixture before concentration
Solution Approach 1:
The patent removes the aqueous carbonate solution from the oxidation system, transitioning from wet oxidation to dry oxidation. This extraction of the problematic aqueous phase eliminates the need for carbonate removal and neutralization steps, directly resolving the technical contradiction by simplifying the overall process while maintaining oxidation functionality.
2Manufacturing precision
If multiple reactors are used in series, then selectivity can be improved, but capital investment and compressor power consumption increase
Solution Approach 1:
The patent optimizes the pressure parameters across the reactor series, using progressively increasing pressure in each subsequent reactor. This parameter change allows each reactor to operate at its optimal pressure for maximum selectivity while the overall system requires fewer reactors, thereby reducing capital investment and compressor power consumption compared to conventional constant-pressure multi-reactor systems.
3Ease of operation
If pumps are used to move oxidation mixture between reactors, then material transfer is achieved, but premature decomposition of CHP may occur
Solution Approach 1:
The patent positions the reactors at progressively reducing elevations from the first to the last reactor in the series. This gravitational potential gradient allows the oxidation mixture to flow automatically from one reactor to the next without requiring pumps, thereby eliminating the mechanical stress and heat input from pumping that could cause premature CHP decomposition, while still achieving effective material transfer.
4Device complexity
If oxidation reactors are positioned at reducing elevations, then pumps are eliminated, but reaction rate may be affected
Solution Approach 1:
The patent compensates for the reduced reaction rate that might result from gravity-driven flow by optimizing other parameters including temperature, pressure, and residence time in each reactor. The progressive pressure increase and temperature optimization in subsequent reactors maintain high reaction rates despite the elimination of pump-induced mixing and heat input.
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 the selectivity of cumene hydroperoxide production to over 94.5% while reducing capital investment and compressor power consumption, and allows for safer and more efficient operation by minimizing the formation of unwanted by-products and impurities.
Implementation Method 1
The liquid phase oxidation of cumene is explained in terms of a radical mechanism by Kazua Hattori et al. in Journal of Chemical Engineering of Japan, vol. 3, no. 1, (1970), p. 72-78.
Implementation Method 2
The liquid phase oxidation of cumene is explained in terms of a radical mechanism by Kazua Hattori et al. in Journal of Chemical Engineering of Japan, vol. 3, no. 1, (1970), p. 72-78.
Implementation Method 3
Positioning the oxidation reactors at reducing elevations, as in JP 2000290249, whereby the need for pumps or other similar means for moving the oxidation reaction mixture from one reactor to the next is removed
Implementation Method 4
The oxidation reaction has been found to be exothermic, and it has accordingly been suggested to cool the oxidation reaction mixture by passing it through cooling coils or the like
Data Source
AI summary
The present invention concerns a process for oxidizing cumene to cumene hydroperoxide using an oxygen containing gas, preferably air, which process comprises —conducting a cumene feed and an oxygen containing gas feed to at least the first oxidation reactor in a series of 3-8 reactors, thereby forming an oxidation mixture, and conducting the formed oxidation mixture from one reactor to the next, preferably after an oxidation reaction has taken place, wherein —the reactors comprise at least one lower pressure oxidizer (1) as the first reactor in the series and at least one higher pressure oxidizer (2) as the last reactor in the series; —any lower pressure oxidizer is operated at a pressure of at least atmospheric pressure and any higher pressure oxidizer is operated at a pressure of at least 0.5 bar higher than said at least one lower pressure oxidizer.