Acoustic Bed Level Measurement in Delayed Coker Drums
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for determining bed levels in delayed coker drums in refineries are either unreliable, costly, or pose safety hazards, leading to inefficiencies such as overfilling or underutilization of the drums, resulting in significant throughput losses and maintenance costs.
Innovation Solution
A non-intrusive method using an acoustic/vibration source to generate vibrations in the drum wall, with strategically placed receivers measuring and analyzing the changes in natural vibration modes and frequencies to estimate the fill level, providing continuous and accurate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ranging radar or sonar methods are installed inside the reactor to measure bed level, then measurement capability is improved, but device complexity and fouling problems worsen
Solution Approach 1:
The patent uses the reactor drum shell as an intermediary medium to transmit acoustic signals. Instead of installing measurement devices inside the reactor, the system attaches transducers to the external shell, which acts as a waveguide to convey acoustic information from the internal bed level to external sensors, thereby avoiding direct installation inside the harsh environment
Solution Approach 2:
The patent replaces mechanical/physical intrusion (installing radar or sonar inside the reactor) with acoustic wave propagation through the shell. The measurement system uses acoustic resonance and vibration characteristics of the drum shell to infer bed level, eliminating the need for physical sensors inside the reactor vessel
2Measurement precision
If radioactive sources are used to measure bed level, then measurement capability is improved, but safety hazards and cost worsen
Solution Approach 1:
The patent substitutes radioactive measurement methods with acoustic resonance methods. The system excites the drum shell at various frequencies and measures the resonant response, using the natural frequency shifts caused by varying bed levels to determine material level without any radioactive materials
Solution Approach 2:
The patent exploits changes in acoustic resonance parameters (natural frequency, damping ratio) of the drum shell as the bed level changes. By monitoring these parameter variations across different excitation frequencies, the system determines bed level without radioactive sources
3Reliability
If a large portion of the drum is left unfilled to prevent overfilling, then safety is improved, but productivity worsens
Solution Approach 1:
The patent implements continuous bed level monitoring using acoustic resonance measurements. The system provides real-time feedback on the actual bed level, enabling operators to optimize drum filling to the true maximum safe level rather than using conservative estimates, thereby maximizing throughput while maintaining safety
Solution Approach 2:
The patent replaces conservative operational practices with precise acoustic measurement-based control. By accurately knowing the bed level through shell resonance analysis, operators can safely utilize more of the drum volume without risk of overfilling, converting unused capacity into productive throughput
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 offers a reliable, low-cost, and safe means to continuously monitor the fill level, reducing the risk of overfilling or underutilization, thereby enhancing operational efficiency and minimizing downtime and maintenance costs.
Implementation Method 1
The method uses an acoustic/vibration source to generate vibration or elastics waves traveling along the vessel wall
Implementation Method 2
The characteristics of the wall vibration depend on the fill level of the vessel. One or more acoustic/vibration receivers are strategically placed on the exterior surface of the wall to measure the vibration response of the wall to the source
Data Source
AI summary
The present invention is a non-intrusive method to determine the fluid level in a vessel. In a preferred embodiment, the vessel is a delayed coker drum in a refinery. Waves are generated in the vessel from an outside source. For wall vibration generated in the frequency range of 1-20,000 Hz, accelerometers on the exterior wall of the vessel measures the frequency of the vibration modes of the vessel. The fluid level can be related to the frequency of the vibration mode.