Separated Urea Reactors and Tube-Side Condenser for Easier Maintenance
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Solution Overview
Problem
Existing urea synthesis apparatuses face challenges in facilitating maintenance, design, and fabrication due to the need for special welding and complex structure, which hinders downsizing and optimal design, and the integration of reactors and condensers leads to inefficient reaction volumes and difficult maintenance.
Innovation Solution
A urea synthesis apparatus comprising separate reactors and a condenser with a process fluid passing through tubes, allowing for easy maintenance and optimal design, using corrosion-resistant materials for tubes and less expensive materials for the shell, and optimizing reaction conditions in multiple reactors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the process fluid is allowed to pass through the shell side in the U-tube submerged condenser, then the urea synthesis reaction is accelerated, but special welding (full penetration welding) is required to prevent crevice corrosion, reducing fabrication efficiency and increasing costs
Solution Approach 1:
The patent inverts the conventional U-tube submerged condenser configuration by allowing the process fluid to flow through the tube side rather than the shell side. This reversal eliminates the need for full penetration welding on the shell side, as the corrosive fluid is now contained within the tubes. The shell can be made of standard material while only the tubes require corrosion-resistant material, significantly simplifying fabrication and reducing costs while maintaining the reaction acceleration benefit.
2Productivity
If the process fluid is allowed to pass through the shell side in the U-tube submerged condenser, then the urea synthesis reaction is accelerated, but a relatively large space is required for maintenance between the tube bundle and shell interior, hindering plant downsizing
Solution Approach 1:
By inverting the flow configuration to allow process fluid through the tube side, the patent eliminates the need for large maintenance spaces between the tube bundle and shell interior. The tube side configuration enables closer spacing of components, reducing the overall volume required for the condenser and associated maintenance access, thereby facilitating plant downsizing while preserving the reaction acceleration capability.
3Device complexity
If the condenser is integrally installed at a higher position than the synthesis reactor, then the apparatus structure is simplified, but the reaction volume is reduced and maintenance becomes difficult
Solution Approach 1:
The patent inverts the conventional configuration by allowing process fluid to flow through the tube side of the condenser, which enables the condenser to be positioned at a lower level than the synthesis reactor while maintaining adequate reaction volume. This inverted flow arrangement provides better access for maintenance and allows for optimized positioning that balances structural simplicity with functional requirements.
4Reliability
If full penetration welding is used to protect welded portions from crevice corrosion, then corrosion resistance is improved, but welding work costs and fabrication time are increased
Solution Approach 1:
By inverting the flow configuration to allow corrosive process fluid through the tube side rather than the shell side, the patent eliminates the need for full penetration welding on the shell side. The tubes can be welded with standard welding techniques since they are internally exposed to the corrosive fluid, while the shell can be made of standard material without special welding protection, significantly reducing welding costs and fabrication time while maintaining adequate corrosion resistance.
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
Facilitates easy maintenance, reduces design constraints, and accelerates the urea reaction by optimizing reaction conditions in multiple reactors, while eliminating the need for special welding and allowing for flexible design and downsizing.
Implementation Method 1
a condenser (C) including a tube (Ct) inside and for condensing a mixed gas separated in the stripper (S) into an absorbing medium to obtain a condensed liquid by allowing a process fluid containing the absorbing medium and the mixed gas to pass through the tube (Ct) and cooling the process fluid with a cooling medium passing through a shell (Cs) side
Implementation Method 2
In a urea synthesis process, usually, carbon dioxide and ammonia are reacted at a high temperature and under a high pressure to obtain a urea synthesis liquid
Data Source
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AI summary
Provided is a urea synthesis apparatus enabling the facilitation of apparatus maintenance, the facilitation of apparatus design or fabrication, and/or the acceleration of a urea reaction. The present invention is a urea synthesis apparatus for reacting ammonia and carbon dioxide to produce urea, and includes a first urea synthesis reactor (R1), a second urea synthesis reactor (R2), a condenser (C), a stripper (S) and means (E) for supplying a first urea synthesis liquid. The condenser (C) is a device for condensing a mixed gas into an absorbing medium to obtain a condensed liquid by allowing a process fluid to pass through a tube (Ct) and cooling it with a cooling medium passing through a shell (Cs) side, the condenser (C) being a device separate from the first urea synthesis reactor (R1) and the second urea synthesis reactor (R2), the first urea synthesis reactor (R1) is a device for obtaining the first urea synthesis liquid from the condensed liquid obtained in the condenser (C), and the second urea synthesis reactor (R2) is a device for obtaining a second urea synthesis liquid from the first urea synthesis liquid.