Liquid CO2 Feed for Urea Synthesis Energy Reduction
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Solution Overview
Problem
The energy efficiency of existing urea production processes is limited by the energy requirements of various components and the multi-stage compressor used for gaseous CO2, which penalizes the overall efficiency of the process.
Innovation Solution
Feeding at least part of the carbon dioxide to the synthesis section in a liquid phase, either alone or in combination with gaseous CO2, to the reactor and/or condenser, reducing the need for a multi-stage compressor and enhancing mass transfer during the reaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If gaseous CO2 is fed to the synthesis section using a multi-stage compressor, then the carbon dioxide can be supplied to the reactor, but the energy consumption increases significantly
Solution Approach 1:
The patent changes the physical state parameter of carbon dioxide from gaseous to liquid phase. By feeding liquid CO2 instead of gaseous CO2 to the synthesis section, the energy-intensive multi-stage compression process is eliminated or significantly reduced, as liquid CO2 requires much less compression work to reach the required operating conditions in the reactor
Solution Approach 2:
The patent replaces the mechanical compression system (multi-stage compressor) with a phase change approach. Instead of mechanically compressing gaseous CO2 through multiple stages, the system uses liquid CO2 which naturally occupies less volume and requires minimal compression, substituting a complex mechanical system with a simpler phase-based solution
2Quantity of substance
If gaseous CO2 is used in the synthesis section, then the reactants can be supplied, but the mixing efficiency and mass transfer are reduced
Solution Approach 1:
The patent changes the physical state parameter of carbon dioxide from gaseous to liquid phase. By feeding liquid CO2 instead of gaseous CO2 to the synthesis section, the energy-intensive multi-stage compression process is eliminated or significantly reduced, as liquid CO2 requires much less compression work to reach the required operating conditions in the reactor
Solution Approach 2:
The patent applies hydraulic principles by using liquid CO2 instead of gaseous CO2. The liquid phase allows for better fluid dynamics and mixing characteristics within the reactor, enabling more effective mass transfer and contact between reactants compared to gaseous phase, thereby improving reaction efficiency
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 improves energy efficiency by reducing energy consumption and enhancing reaction yield, as pumping liquid CO2 requires less energy than compressing gaseous CO2, and allows for more effective mixing of reactants in the synthesis section.
Implementation Method 1
at least part of the carbon dioxide is fed to the synthesis section in liquid phase
Implementation Method 2
enhancing mass transfer during the reaction
Implementation Method 3
urea is produced by reacting liquid ammonia and gaseous carbon dioxide (CO2) in a high-pressure reactor
Implementation Method 4
urea is produced, also in liquid phase, by dehydratation of said ammonium carbamate
Data Source
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AI summary
A process for producing urea is disclosed, wherein liquid ammonia and carbon dioxide are reacted in a high-pressure synthesis section (100), and at least part of the carbon dioxide is fed to said synthesis section (100) in liquid phase. A plant operating according to said process and a method for modernizing existing plants accordingly are also disclosed.