Ethanol Conversion Reactor Heat Balancing for Propylene Yield
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Solution Overview
Problem
Existing methods for converting ethanol to hydrocarbons and aromatic compounds face challenges in controlling the internal temperature of reactors due to endothermic and exothermic reactions, leading to reduced yields and increased by-products such as coke.
Innovation Solution
A method involving a dehydration step followed by an olefin conversion step, where the raw material mixture contains ethanol, ethylene, and ether, with a specific molar ratio adjustment to balance exotherm and endotherm, using a dehydration and olefin conversion catalysts to control reactor temperature effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If dehydration reaction of ethanol is performed to produce ethylene, then ethylene yield is improved, but reactor temperature decreases due to endothermic nature requiring excessive heat input
Solution Approach 1:
The patent combines the endothermic dehydration reaction of ethanol with the exothermic oligomerization reaction of ethylene in a single reactor system. The heat generated from the exothermic oligomerization reaction compensates for the heat consumed by the endothermic dehydration reaction, thereby maintaining reactor temperature without requiring excessive external heat input while producing both ethylene and higher olefins efficiently
2Quantity of substance
If ethylene is converted to propylene or aromatic compounds through exothermic reaction, then target compound yield is improved, but reactor temperature increases causing increased by-products such as coke
Solution Approach 1:
The patent converts the harmful effect of temperature increase (which causes coke formation) into a beneficial outcome by using the exothermic oligomerization reaction heat to compensate for the endothermic dehydration reaction. This thermal coupling allows the reaction to proceed at optimal temperatures, improving propylene yield while minimizing coke by-products through proper heat balance management
3Productivity
If zeolite catalyst is used for olefin conversion, then catalytic activity is improved, but temperature control becomes difficult due to increased endotherm and exotherm
Solution Approach 1:
The patent employs a dual-function catalyst system that combines dehydration catalyst activity with oligomerization catalyst activity, allowing both endothermic dehydration and exothermic oligomerization to occur simultaneously. The heat generated from oligomerization compensates for the heat consumed by dehydration, enabling effective temperature control even with highly active zeolite catalysts that would otherwise cause difficult temperature management
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
The method allows for easy control of reactor temperature, enhancing the yield of target compounds like propylene and aromatic compounds while minimizing by-products, thus improving the efficiency of ethanol conversion.
Implementation Method 1
a dehydration step of subjecting a dehydration raw material containing ethanol to dehydration reaction by a dehydration catalyst
Implementation Method 2
an olefin conversion step of contacting a raw material mixture containing the dehydration reaction gas with an olefin conversion catalyst
Implementation Method 3
The dehydration reaction is endothermic reaction and therefore has the difficulty in adjusting an internal temperature of a reactor due to a decreased temperature of the reactor
Implementation Method 4
ethylene conversion to propylene or an aromatic compound is exothermic reaction and may therefore reduce the yield of a target compound by increasing the amount of by-products such as coke, due to an elevated internal temperature of the reactor
Data Source
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AI summary
Provided is a method for converting ethanol, comprising: a dehydration step of subjecting a dehydration raw material containing ethanol to dehydration reaction by a dehydration catalyst in a reactor to obtain a dehydration reaction gas containing ethylene; and an olefin conversion step of contacting a raw material mixture containing the dehydration reaction gas with an olefin conversion catalyst in a reactor to obtain a reaction gas containing an olefin having 3 or more carbon atoms, wherein the raw material mixture contains an ether, and in the raw material mixture, a value represented by the following expression (1): EYEtOH−10×EtherEtOH+EY+Ether wherein EY represents a molar quantity of ethylene contained in the raw material mixture, EtOH represents a molar quantity of ethanol contained in the raw material mixture, and Ether represents a molar quantity of the ether contained in the raw material mixture is 0.20 to 4.0.