Ethanolamine Process Segmentation for Ammonia Recovery
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Solution Overview
Problem
The ethanolamines production process faces challenges in achieving high ammonia to water ratios for improved process economics and efficiency while maintaining product quality, as reducing water content often leads to excess pressures and product discoloration due to high temperatures.
Innovation Solution
A process involving mixing a recycle water-ammonia solution with ethylene oxide, followed by staged separation and stripping columns to maintain low temperatures and optimize ammonia recovery, reducing water content without compromising product quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If water content is reduced to improve process economics and efficiency, then ammonia to water ratio increases and process efficiency improves, but vapor pressure increases causing excess pressures in the absorber and product discoloration due to high temperatures
Solution Approach 1:
The single absorber is divided into two separate absorbers: a first absorber for absorbing ammonia from reactor effluent at higher temperatures, and a second absorber for absorbing ammonia from stripper overhead at lower temperatures. This segmentation allows each absorber to operate at optimized temperature conditions, preventing product discoloration while maintaining high ammonia-to-water ratios and process efficiency.
Solution Approach 2:
Different temperature conditions are applied to different parts of the absorption system. The first absorber operates at higher temperatures suitable for handling hot reactor effluent, while the second absorber operates at lower temperatures (below 150°C) to prevent discoloration of the ethanolamines product. This local quality approach allows simultaneous optimization of both process efficiency and product quality.
2Productivity
If water content is reduced to improve process economics, then ammonia to water ratio increases, but absorber backpressure increases requiring higher temperatures in stripping column and evaporator
Solution Approach 1:
The absorption system is segmented into two absorbers with different operating conditions. The first absorber handles the hot reactor effluent at higher temperatures, while the second absorber handles the stripper overhead at lower temperatures. This segmentation prevents the need to increase stripping column temperatures to manage absorber backpressure, as each absorber operates independently at its optimal temperature.
Solution Approach 2:
The invention changes the operating temperature parameter of the absorbers to resolve the contradiction. By operating the first absorber at higher temperatures and the second absorber at lower temperatures (below 150°C), the system maintains high ammonia-to-water ratios without requiring excessive temperatures in the stripping column and evaporator, thus improving process economics while avoiding product 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 allows for efficient ethanolamines production with high ammonia to water ratios, maintaining temperatures below 150°C to enhance process economics and product quality, reducing water usage, and minimizing product discoloration.
Implementation Method 1
separating, in a first ammonia stripping column, the effluent reaction mixture into a rich ammonia-water mixture vapor overhead and a product solution bottoms liquid
Implementation Method 2
separating, in a first evaporator, the water-ethanolamines solution into steam overhead and a concentrated water-ethanolamines solution
Data Source
Figure 1
AI summary
A process for the preparation of ethanolamines comprising reacting a water-ammonia solution with ethylene oxide to form an effluent reaction mixture comprising unreacted ammonia, water and ethanolamines. This effluent reaction mixture is then subjected to a succession of steps to, inter alia, separate the ethanolamines.