Urea Synthesis Steam Compressor for Heat Recovery
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Solution Overview
Problem
Existing urea production processes face inefficiencies in heat recovery and energy usage, particularly in non-isobaric loops where the steam produced is not suitable for downstream processes, and revamping existing plants is costly and requires significant downtime.
Innovation Solution
A process that involves compressing steam generated in the high-pressure condenser to increase its pressure and temperature, allowing it to be used effectively in downstream sections, and using an electric compressor to reduce energy consumption, thereby optimizing the high-pressure loop and reducing the need for additional heat exchange surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If steam is produced in the high-pressure condenser at lower pressure, then heat recovery is improved, but the steam temperature and pressure become insufficient for downstream processes
Solution Approach 1:
The patent changes the pressure parameter of the steam produced in the high-pressure condenser by introducing a steam compressor. The compressor increases the pressure of the steam from condensation pressure (e.g., 70-90 bar) to a higher pressure (e.g., 100-250 bar), thereby increasing the temperature as well. This allows the steam to meet the requirements for downstream processes while maintaining efficient heat recovery at the lower condensation pressure.
2Productivity
If the synthesis loop operates at high pressure, then reactor conversion is improved, but the stripping process requires higher pressure equipment
Solution Approach 1:
The patent segments the pressure levels in the synthesis loop by introducing a steam compressor that operates at a different pressure level. The high-pressure condenser operates at lower pressure (70-90 bar) for efficient heat recovery, while the steam compressor raises the steam pressure to match the high-pressure reactor conditions (100-250 bar). This segmentation allows each component to operate at its optimal pressure independently.
3Productivity
If existing plants are revamped to increase capacity, then productivity is improved, but investment costs and downtime increase
Solution Approach 1:
The steam compressor serves multiple functions: it increases steam pressure for downstream processes, recovers heat more efficiently from the condenser, and enables capacity increases without requiring extensive modifications to existing heat exchange surfaces. This multi-functionality allows existing plants to be revamped with minimal downtime and investment while achieving higher productivity.
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 enhances heat recovery efficiency, reduces energy consumption, and allows for capacity increases without extensive modifications, minimizing downtime and investment costs while maintaining high-quality urea production.
Implementation Method 1
a high-pressure condenser, wherein the gaseous phase is condensed to form a liquid recycle solution
Implementation Method 2
a steam compressor arranged to compress the steam flow to a pressure and temperature greater than condensation pressure and temperature, respectively
Implementation Method 3
reacting ammonia and carbon dioxide to form an aqueous solution of urea
Implementation Method 4
a stripper fed with reaction effluent from the reactor, wherein the carbamate is decomposed to CO2 and NH3
Data Source
AI summary
A process for synthesis of urea from CO2 and NH3 wherein a steam flow (13) produced in the condenser (3) of a high-pressure synthesis loop is compressed to raise its pressure and temperature before using the steam as a heat source for a downstream step of the process.