Method and assembly for manufacturing an olefin
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Solution Overview
Problem
The oxidative dehydrogenation (ODH) process for producing olefins faces challenges in separating process gases due to low methane content, leading to significant product and educt losses, as well as safety concerns from excessive oxygen and carbon monoxide concentrations, which are not effectively addressed by traditional separation methods.
Innovation Solution
A method involving a two-stage low-temperature rectification process, using a liquid reflux predominantly containing hydrocarbons with N-1 carbon atoms to separate olefins with N carbon atoms, which reduces oxygen content and enhances separation efficiency, thereby minimizing product losses and safety risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If traditional separation methods are used for ODH process gas, then separation of methane and lower-boiling components can be achieved, but significant product and reactant losses occur due to low methane content
Solution Approach 1:
The patent introduces an intermediary substance (refrigerant or liquid absorbent) to facilitate the separation process. This intermediary enables efficient separation of olefins from process gas components even when methane content is low, thereby reducing product and reactant losses while maintaining separation efficiency
Solution Approach 2:
The patent employs parameter changes by adjusting temperature and pressure conditions to optimize the separation process. By controlling these parameters, the method achieves efficient separation of olefins from process gas components containing low methane content, minimizing losses while maintaining separation effectiveness
2Quantity of substance
If traditional demethanization is applied to ODH process gas, then methane separation can be achieved, but oxygen and carbon monoxide accumulate to dangerous concentrations
Solution Approach 1:
The patent extracts harmful components (oxygen and carbon monoxide) from the process gas stream during the separation process. By removing these dangerous substances alongside methane separation, the method prevents their accumulation to dangerous concentrations while achieving the required methane separation
Solution Approach 2:
The patent converts the potentially harmful accumulation of oxygen and carbon monoxide into a benefit by utilizing these components in the refrigeration cycle or absorption process. This approach not only prevents dangerous accumulation but also recovers energy or improves process efficiency
3Productivity
If complete oxygen conversion is achieved in the reactor, then olefin yield increases, but catalyst reduction occurs leading to performance loss
Solution Approach 1:
The patent applies preliminary action by pre-heating and pre-mixing the feedstock with controlled oxygen content before entering the reactor. This preliminary preparation ensures optimal reaction conditions that maximize olefin yield while preventing catalyst reduction, as the controlled oxygen conversion is achieved through precise feed composition control
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 significantly reduces product losses and safety hazards by effectively separating olefins and reducing oxygen content below critical levels, improving the economic viability and safety of the ODH process.
Implementation Method 1
a first low-temperature rectification is carried out on the condensates
Implementation Method 2
cooling the separation element stepwise at a plurality of temperature levels and separating condensates from the separation element
Data Source
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AI summary
Proposed is a process for producing an olefin having N carbon atoms in which using a dehydrogenation a process gas containing at least the olefin having N carbon atoms, a paraffin having N carbon atoms and a hydrocarbon having N - 1 carbon atoms is formed and in which using at least a portion of the process gas a separation input is formed which is subjected to a low-temperature separation in which the separation input is cooled stepwise over a plurality of temperature levels and condensates are separated from the separation input, wherein the condensates are at least partly subjected to a first low-temperature rectification to obtain a first gas fraction and a first liquid fraction, wherein the first gas fraction contains at least the olefin having N carbon atoms in a lower proportion than in the condensates and the hydrocarbon having N-1 carbon atoms in a higher proportion than in the condensates. It is provided that the first gas fraction is at least partly subjected to a second low-temperature rectification using a liquid reflux containing predominantly or exclusively the hydrocarbon having N-1 carbon atoms in which the first gas fraction is depleted in the olefin having N carbon atoms. The present invention also relates to a corresponding plant (100).