MTO Catalyst Circulation With Low-Oxygen Regenerated Catalyst Return
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Solution Overview
Problem
The production of lower olefins is hindered by the presence of impurities such as alkyne, dialkene, and oxygenate due to excessive oxygen or steam in the reactor and regenerator, leading to catalyst degradation and increased catalyst loss.
Innovation Solution
Implementing a catalyst flow rate control device on the spent and regenerated catalyst lines, along with stripping and degassing devices, to regulate oxygen and steam content below 0.1% in the gas phase, and using steam or nitrogen as stripping and degassing media to enhance catalyst regeneration and separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If catalyst circulation is implemented between reactor and regenerator, then catalyst activity is maintained, but oxygen and steam cross-contamination occurs causing impurity formation
Solution Approach 1:
The patent divides the catalyst circulation system into separate controlled zones: the reactor, the regenerator, and intermediate transfer lines. By segmenting the system and controlling the atmosphere in each zone independently, cross-contamination of oxygen and steam is prevented while maintaining continuous catalyst circulation and activity.
Solution Approach 2:
The patent introduces intermediate transfer lines with flow rate control devices as mediators between the reactor and regenerator. These intermediaries allow catalyst to be transferred while controlling the gas phase composition, preventing direct mixing of oxygen-rich and steam-rich environments that would cause impurity formation.
2Reliability
If excessive oxygen is introduced into the reactor, then catalyst regeneration is enhanced, but byproducts such as alkyne, dialkene, and oxygenate increase
Solution Approach 1:
The patent applies local quality by providing different gas phase compositions in different locations: the reactor receives controlled low-oxygen atmosphere to prevent byproduct formation, while the regenerator receives oxygen-rich atmosphere for catalyst regeneration. The flow rate control devices ensure each zone receives the appropriate local quality needed for its function.
3Ease of manufacture
If excessive steam is introduced into the regenerator, then catalyst cleaning is improved, but catalyst pores expand and fine powder increases causing catalyst loss
Solution Approach 1:
The patent applies preliminary action by introducing steam into the regenerator in a controlled manner before complete catalyst regeneration occurs. The flow rate control device regulates steam introduction to achieve cleaning effect while preventing excessive steam from causing pore expansion and fine powder formation that would lead to catalyst loss.
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
Reduces impurities in the product and minimizes catalyst loss, improving the yield and quality of lower olefins.
Implementation Method 1
contacting the catalysts entering the second dense phase stripping zone with a stripping medium to remove the entrained product stream
Implementation Method 2
a second catalyst flow rate control device arranged on the regenerated catalyst line, and the second catalyst flow rate control device controls the oxygen volume content in the gas phase component at the outlet of the regenerated catalyst line to be less than 0.1%
Implementation Method 3
feeding spent catalysts from the at least partially deactivated catalysts to a regenerator for regeneration
Implementation Method 4
In an MTO reactor, under certain conversion conditions, methanol or a mixture of methanol and a diluent is contacted with a MTO catalyst
Data Source
AI summary
The present invention relates to a process of converting methanol to olefins, comprising: feeding a feedstock comprising methanol to a fluidized bed reactor to contact with catalysts to produce an olefin product, wherein the process at least partially deactivates the catalysts to format least partially deactivated catalysts; feeding spent catalysts from the at least partially deactivated catalysts to a regenerator for regeneration, thereby forming regenerated catalysts, and returning the activated catalysts from the regenerated catalysts to the reactor via a regenerated catalyst line; characterized in that on the regenerated catalyst line, the oxygen content by volume in the gas phase component at the outlet of the regenerated catalyst line is controlled to be less than 0.1%, preferably less than 0.05%, and more preferably less than 0.01%.