Ethane ODH Recycle Scheme for Ethylene-Acetic Acid Ratio Control
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Solution Overview
Problem
Existing oxidative dehydrogenation processes of ethane to ethylene and acetic acid produce these products in fixed ratios, making it difficult to meet the variable demands of downstream processes requiring both ethylene and acetic acid in specific proportions, especially when conventional methods result in undesirable high acetic acid content.
Innovation Solution
A process that adjusts the ethylene-to-acetic acid ratio by recycling ethylene from the product stream back into the oxidative catalytic dehydrogenation using a catalyst system with molybdenum, vanadium, and niobium, optionally with tellurium, and employing operational adjustments to enhance ethylene content in the feed mixture, allowing precise matching of downstream process demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If oxidative dehydrogenation is used to produce ethylene and acetic acid, then the products can be obtained in a single process, but the ethylene-to-acetic acid ratio is fixed and cannot be adjusted to meet varying downstream demands
Solution Approach 1:
The process is divided into two independent production paths: one for ethylene production and another for acetic acid production. By separating the reaction pathways and controlling them independently, the plant can adjust the output ratio of ethylene to acetic acid according to downstream demands, while maintaining high production efficiency through the integrated oxidative dehydrogenation process.
2Ease of manufacture
If conventional oxidative dehydrogenation is used, then the process is simple and economical, but excessive acetic acid is formed which is undesirable when ethylene is the primary target
Solution Approach 1:
The process employs dynamic control of reaction parameters including temperature, pressure, and residence time to adjust the selectivity of the oxidative dehydrogenation reaction. By dynamically optimizing these parameters, the process can minimize acetic acid formation when ethylene is the primary target, while maintaining process simplicity and economic viability.
3Quantity of substance
If the ethylene content in feed mixture is increased to meet downstream demands, then the acetic acid production increases, but this reduces flexibility in adjusting product ratios
Solution Approach 1:
The process implements feedback control mechanisms that continuously monitor the ethylene-to-acetic acid ratio in the product stream and adjust reaction conditions accordingly. This allows the system to maintain the desired product ratio by dynamically adjusting feed composition and reaction parameters, providing flexibility to meet varying downstream demands.
Solution Approach 2:
The process utilizes changes in physical and chemical parameters such as temperature, pressure, and catalyst composition to control the reaction selectivity. By adjusting these parameters, the process can optimize the ethylene-to-acetic acid ratio according to downstream demands without being constrained by fixed feed composition requirements.
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
Enables flexible adjustment of ethylene-to-acetic acid ratios to meet downstream process requirements, reducing excess ethylene production and optimizing plant operation efficiency while utilizing existing equipment.
Implementation Method 1
oxidative catalytic dehydrogenation using a catalyst containing at least molybdenum, vanadium, and niobium, and optionally tellurium as a mixed oxide
Implementation Method 2
Due to the exothermic nature of the reactions involved and the practically irreversible formation of water
Implementation Method 3
oxidative dehydrogenation (ODH) of paraffins with two to four carbon atoms... these paraffins react with oxygen to form, among other things, the respective olefins and water
Data Source
Figure 1
AI summary
The present invention relates to a method (100) for producing ethylene and acetic acid, in which ethane and oxygen are subjected in a feed mixture (1) to an oxidative catalytic dehydration (110) so as to obtain a product mixture (2) containing ethylene, acetic acid and further components. The feed mixture (1) has an ethylene content of 0.25 to 30 mol.%. At least a part of the ethylene content of the feed mixture (1) of the oxidative catalytic dehydration is formed by ethylene, which is contained in the product flow (2) and is fed back into the oxidative catalytic dehydration (110). The product mixture (2) or part thereof is subjected to a primary treatment (120-170), from which a subsequent mixture (5) is removed and is depleted in carbon dioxide and water compared to the product mixture (2). The subsequent mixture (5) or part thereof is fed as cryogenic separation feed to a cryogenic separation (180, 190) which includes a demethanisation (180) and an ethane-ethylene separation (190). At least a part of the cryogenic separation feed is fed as a demethanisation feed to the demethanisation (180) and a heavy fraction (6) and a light fraction (7) are formed as head fraction in the demethanisation (180), the heavy fraction (6) or part thereof being fed to the ethane-ethylene separation (190), and the light fraction (7) or part thereof being fed back to the oxidative dehydration (110). The present invention also relates to a system for producing ethylene and acetic acid and to a method and a system for producing a target compound using ethylene and acetic acid.