Olefin Oxide Reactor Start-Up via Internal Heat
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Solution Overview
Problem
Conventional silver-based catalysts used in the epoxidation of olefins have low selectivity, and existing start-up processes for high selectivity catalysts lack effective control over start-up temperature and oxygen outlet concentration, limiting the efficiency of the epoxidation process.
Innovation Solution
A method that uses an internal oxidation reaction within the reactor to achieve a controlled start-up temperature exceeding the maximum achievable with external heating sources, by initially heating the reactor with steam and then increasing the temperature through the heat of reaction generated by introducing olefin and oxygen, maintaining the reactor temperature between 240° to 290° C. for catalyst conditioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If external heating sources are used to heat the reactor during start-up, then the reactor can be heated, but the maximum achievable temperature is limited
Solution Approach 1:
The reactor system uses the oxidation reaction itself to generate the heat required for temperature increase, rather than relying on external heating sources. The exothermic nature of the oxidation reaction provides self-heating capability, allowing the reactor to exceed the temperature limits of external heating systems.
Solution Approach 2:
The patent utilizes oxidation reaction to generate heat for reactor temperature increase. By controlling the oxidation process, the system can achieve temperatures beyond what external heating sources can provide, using the chemical energy of oxidation to drive the thermal requirements.
2Manufacturing precision
If high selectivity silver-based catalysts are used, then olefin oxide selectivity is improved, but the catalyst requires conditioning at temperatures exceeding external heating capabilities
Solution Approach 1:
The catalyst conditioning process utilizes the heat generated by the oxidation reaction to reach the required conditioning temperatures, eliminating the need for external heating sources that cannot achieve the necessary temperature range for optimal catalyst performance.
Solution Approach 2:
The patent changes the thermal parameters of the system by using the exothermic oxidation reaction to generate heat, thereby achieving catalyst conditioning temperatures that exceed the capabilities of conventional external heating systems while maintaining high selectivity.
3Temperature
If the reactor temperature is increased beyond external heating limits, then catalyst heat-treating stage is extended, but control over temperature becomes difficult
Solution Approach 1:
The system monitors and controls the oxidation reaction conditions to manage the heat generation, allowing temperature control within the range of 240°C to 290°C. By adjusting reaction parameters and maintaining oxygen outlet concentration above 0.5%, the system achieves controlled self-heating that extends catalyst heat-treating while maintaining operational control.
4Reliability
If oxygen concentration is not controlled during start-up, then oxidation reaction may occur uncontrollably, but controlling oxygen outlet concentration adds process complexity
Solution Approach 1:
The patent implements control of oxygen outlet concentration to maintain it above 0.5%, providing feedback control that ensures safe and reliable operation of the oxidation reaction during catalyst start-up and conditioning, preventing uncontrolled reactions while managing process parameters.
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 method allows for higher catalyst temperatures beyond the limits of external heating systems, maintaining optimal reactor conditions and extending the catalyst heat-treating stage at lower coolant temperatures, thereby enhancing the selectivity and efficiency of the epoxidation process.
Implementation Method 1
increasing the temperature through the heat of reaction generated by introducing olefin and oxygen
Implementation Method 2
initially heating the reactor with steam
Data Source
AI summary
A method to achieve a controlled start-up temperature of an expoxidation process which exceeds the maximum achievable temperature of the epoxidation reactor relative to using an external heat source. The method of the present invention employs an oxidation reaction within the reactor to bring the temperature of the reactor to a temperature that is suitable for conditioning a high selectivity catalyst. The method of the present invention includes first bringing a reactor including a high selectivity catalyst to a first temperature using the external heat source to the reactor, while staying within the reactor design limitations and maintaining a gas flow to the reactor that is within 25 to 100% of the design rates. Once the reactor has achieved the first temperature, at least an olefin, e.g., ethylene, and then oxygen are introduced to the reactor feed gas. The olefin and oxygen concentrations are adjusted to have a heat of reaction that will allow raising the reactor gas flow to 100% of design and then have sufficient heat of reaction to raise the reactor temperature to a second temperature which is greater than the first temperature and greater than the temperature of the reactor achievable by the external heat source.