Urea Stream Density Measurement for Real-Time N/C Ratio Control
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Solution Overview
Problem
Existing methods for measuring N/C and H/C ratios in urea synthesis processes are discontinuous, pose safety risks, require expensive equipment, and suffer from accuracy and reliability issues due to the corrosive nature and dissolved gases in urea-containing streams.
Innovation Solution
Utilizing a vibrating density meter to directly measure density and viscosity of urea synthesis process streams, allowing for the calculation of N/C and H/C ratios without the need for sampling lines, and using a control system to monitor these parameters in real-time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If off-line analysis of samples is used to measure N/C and H/C ratios, then measurement can be performed, but the method introduces safety concerns and is discontinuous, not allowing real-time optimization
Solution Approach 1:
The patent replaces manual mechanical sampling with an automated density measurement system using a Coriolis mass flow meter. The meter directly measures density of the process stream, which correlates to N/C ratio, eliminating the need for manual sample extraction and providing continuous real-time data for process optimization.
Solution Approach 2:
The patent uses density as an intermediary parameter to indirectly determine the N/C and H/C ratios. Instead of directly measuring composition parameters, the system measures density (a physical property) and uses correlation relationships to derive the compositional information, enabling continuous monitoring without direct chemical analysis.
2Productivity
If Coriolis mass flow meters are used to determine N/C indirectly through density measurement, then continuous measurement is achieved, but expensive equipment and dedicated extraction lines with pumps are required
Solution Approach 1:
The Coriolis mass flow meter is designed to perform multiple functions: it measures both mass flow rate and density simultaneously. This eliminates the need for separate measurement devices and reduces the overall equipment complexity while maintaining continuous measurement capability.
Solution Approach 2:
The measurement system utilizes the existing process stream flow itself to perform the measurement. The Coriolis meter measures density of the flowing stream in situ, and the system uses the process flow to deliver samples for analysis and return them, making the process self-sufficient without requiring additional complex infrastructure.
3Measurement precision
If samples are extracted from pressure vessels for analysis, then measurement can be performed, but dedicated expensive equipment such as pump, extraction line and returning line are needed
Solution Approach 1:
The patent extracts only the essential measurement function from the complex sampling system. Instead of extracting physical samples through complex lines, the system extracts density information directly from the flowing stream using the Coriolis meter, taking out only the necessary data while leaving the process stream intact.
Solution Approach 2:
The system creates a correlation model (a mathematical copy) between density measurements and N/C ratios. This allows the system to determine compositional parameters without physically separating or significantly altering the process stream, using the density-c composition relationship as a virtual model for indirect measurement.
4Measurement precision
If the urea stream is extracted for analysis, then measurement can be performed, but the stream may crystallize into the extraction line requiring dedicated cleaning systems
Solution Approach 1:
The patent replaces physical sample extraction with in-situ density measurement. The Coriolis mass flow meter measures density of the stream while it is flowing through the process line, eliminating the need for separate extraction lines where crystallization could occur. The measurement is performed within the process stream itself.
Solution Approach 2:
The system uses density as an intermediary measurement parameter that can be obtained without physically removing or isolating the urea stream. By measuring density in situ and using correlation to determine N/C ratios, the system avoids direct handling of the stream in extraction lines where crystallization and clogging problems would occur.
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
Provides accurate and reliable measurements of N/C and H/C ratios in real-time, eliminating the need for sampling lines and ensuring safety, while maintaining high accuracy and reliability even under supercritical conditions.
Implementation Method 1
a vibrating density meter to measure the density and possibly the viscosity of a target process stream
Data Source
AI summary
A method for determining at least one composition parameter of a urea-synthesis process stream comprising the step of measuring the density of said stream by means of a vibration density meter in contact with said stream and determining the ammonia/carbon dioxide molar ratio N/C of said stream on the basis of the density measured by said vibration density meter.