Oxidative Dehydrogenation Feed Preheater Temperature Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Oxidative dehydrogenation (ODH) processes face challenges in minimizing side reactions and fouling due to high temperatures, which affect the yield of ethylene production and increase operational costs and maintenance needs.
Innovation Solution
A feed preheater is used to heat the reactor feed to between 150° C. and 250° C., with the heated feed being introduced into the ODH reactor within 15 seconds of reaching maximum temperature to minimize thermal shock and reduce unwanted reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the feed gas is heated to high temperatures in the preheater, then the reaction temperature is achieved, but side reactions and fouling increase
Solution Approach 1:
The feed gas is preheated to the reaction temperature (150-250°C) in a preheater before entering the ODH reactor. This preliminary heating action allows the gas to reach the required temperature gradually, minimizing thermal shock and reducing unwanted side reactions and fouling that would occur with direct high-temperature exposure.
Solution Approach 2:
The patent minimizes the residence time of the feed gas in the preheater to less than 15 seconds. By rushing the heating process through quickly, the system achieves the necessary temperature increase while limiting the time available for harmful side reactions and fouling to occur during the heating phase.
2Temperature
If the residence time in the preheater is increased, then the feed gas reaches reaction temperature, but side reactions increase
Solution Approach 1:
The preheater is designed to heat the feed gas rapidly to the reaction temperature within less than 15 seconds of residence time. This rushing through approach achieves the necessary temperature increase while minimizing the time available for harmful side reactions to occur during preheating.
3Productivity
If steam cracking is used to produce olefins, then high olefin yield is achieved, but fuel demand and equipment cost increase
Solution Approach 1:
The patent changes the fundamental process parameters from steam cracking (high temperature, endothermic) to oxidative dehydrogenation (lower temperature, exothermic). By using oxygen as the oxidizing agent and operating at lower temperatures (150-250°C), the process achieves comparable olefin yields while dramatically reducing fuel demand and eliminating the need for high-temperature resistant equipment.
Solution Approach 2:
The patent converts the typically harmful oxidation reactions (which cause fouling and reduce yield) into a beneficial exothermic process. By carefully controlling the oxidation conditions, the heat generated by oxidation is used to maintain reaction temperature, eliminating the need for external fuel input while the selective oxidation pathway promotes olefin formation rather than degradation.
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 decreases side reactions and fouling, improving plant economics and operational reliability by maintaining a lower feed stream temperature and reducing residence time, thereby enhancing ethylene yield and reducing maintenance requirements.
Implementation Method 1
the feed preheater is configured to heat a reactor feed to between about 150° C. and about 250° C.
Implementation Method 2
Oxidative dehydrogenation (ODH) is an alternative to steam cracking that is exothermic and produces little or no coke
Data Source
AI summary
Embodiments described in examples herein provide methods and systems for increasing a yield from an oxidative dehydrogenation (ODH) reactor. An exemplary method includes controlling a temperature of a feed gas composition at less than 250° C. The feed gas composition is flowed through a feed preheater to form a heated feed gas, wherein in the feed preheater the feed gas composition is heated to between 150° C. and 250° C. The heated feed gas is flowed into the ODH reactor less than 15 seconds after leaving the feed preheater.