In industrial processes, multiphase flow is the most important detection and control parameter, especially the real-time flow rate of a phase in multiphase flow is very important for industrial process monitoring. In order to accurately obtain the flow rate of multiphase flow, the velocity and concentration of each phase are two important process parameters.
For particle velocity measurement, the main methods used in recent years include laser Doppler velocimetry, high-speed image analysis, fiber particle velocity probe measurement method, collision momentum method, isokinetic sampling method, etc.
For particle concentration measurement, the main means include cross-section imaging technology, fiber probe concentration measurement method, capacitance probe measurement technology, differential pressure method, etc.
The above test methods may have high requirements for the use environment, or are difficult to be applied to industrial environments due to the complexity of the equipment, for example, the laser Doppler velocimetry technology has high accuracy and is only suitable for very low particle concentrations.
Fiber optic probe method
The fiber optic probe method has great advantages in practical applications:
Using the principle of laser reflection, the velocity and concentration of particles can be obtained at the same time according to the analysis of the light reflection signal, and the process can be measured in situ
Fiber optic probes are insensitive to temperature and pressure, etc., and the measurement results are less affected by the environment
The probe can be improved to adapt to the measurement environment of high temperature and high pressure
The equipment is simple, easy to operate, and has little interference with the flow field.
The laser velocity concentration tester LABASES based on the fiber probe method to measure the velocity and concentration of discrete phases (particles, bubbles, droplets, etc.) mainly includes:
Laser transmitters, receivers and optical fibers (for generating and receiving laser signals);
Photodiodes and amplifiers (used to convert optical signals into electrical signals);
PC and data processing software Labasoft can be used to analyze electrical signals, fit with calibration data to calculate concentrations, and perform correlation analysis to obtain speed.
In addition, it is equipped with a customized calibration device, which can be calibrated to obtain the correspondence between the voltage signal and the concentration.
Labasys Velocity Concentration Measurement Principle
Labasys measurements are based on the principle of laser backscattering, in which the laser signal emitted by the light-emitting diode is transmitted via a fiber optic cable to the flow field region, where it is reflected after encountering particlesThe probe is able to receive the reflected signal and convert it into a voltage signal through a photodiode, which is proportional to the intensity of the detected light signal, and the intensity of the reflected light is related to the concentration of the particlesThe voltage signal is processed by a signal amplifier and analyzed by the data processing software Labasoft, which, in combination with the calibration data, calculates the concentration of the particles.
EditorIn the actual measurement process, the particle cluster composed of a large number of fine particles has a certain surface characteristic, which is reflected in the voltage signal obtained by the measurement. Assuming that the characteristics of the particle clusters remain unchanged over a short period of time, there is a very good correlation between the signals obtained with the two probes. Each probe obtains a set of voltage signals respectively, and the time difference of the signals can be obtained by cross-correlation analysis of several groups of voltage signals, and the speed of particle movement can be calculated in combination with the position relationship between the probes.
labasys：Positioned for industrial-grade applications
Labasys velocity concentration measurement devices were designed and built with the extremely harsh conditions of industrial applications in mind.
Labasys equipment housing materials are highly strong and wear-resistant, allowing them to operate continuously in processes with high concentrations of particles moving at high speeds
LABASEYS can be used normally at high temperatures, up to 1100 reactors;
For the high-pressure reaction conditions, LABASYS has a unique sealing device, which can ensure normal use in a 6MPa environment without causing pressure leakage
For severe wear caused by the high-speed movement of dense phase particles, LABASEYS has a double-layer seal with a sapphire window to ensure that the fiber optic probe will not be worn and affect the measurement accuracy
When measuring highly viscous or ultra-fine powders, Labasys' patented Clean Unit technology ensures cleanliness in front of the lens and eliminates signal drift due to lens coverage.
In addition to components such as cooling units, cleaning units, pressure and wear protection, Labasys offers a range of unique customisation designs: all lenses and electronics are integrated into a lightweight, easy-to-operate deviceThanks to its modular design, it can be flexibly adapted to different working environments and measuring tasks, and components can be easily replacedCustomized equipment connection valves ensure installation and removal at high pressuresCalibration device: fast and accurate calibration;Gas-liquid-solid three-phase measurement;Post-processing Labasoft satisfies ** offline processing, and the flow-dot module can analyze particles at 0 velocity;Customized equipment support bench: to ensure the installation, disassembly and movement of the equipment at 10 bar pressureThe special functions of LABASEYS ensure that it can obtain relatively high concentration and speed test accuracy in harsh environments with high temperature and high pressure, flammable and explosive hazardous environments.
Labasys velocity concentration measurement devices are mainly used in:
Gas-solid two-phase flow: Fluidized Bed (CFB), Fluid Catalytic Cracking (FCC), Cyclone Separator, Mixer, Milling, Pneumatic Conveying, Spray Dryer, etc
Liquid-solid two-phase flow: Stirring tank, crystallization, suspension treatment (e.g. pulp processing);
bubbles or droplets: Nebulization, bubbling bed, separation column, etc.
Labasys test equipment includes a variety of models, such as Labasys 100, Labasys Control EX, Labasys Control EX BF, different models can meet the testing needs of different environments.
The Labasys 100 is the basic configuration of the Labasys test system and is designed to meet the needs of simultaneous measurement of speed and concentration. 2 or 3 probes can be selected, corresponding to 1D and 2D velocity measurements, respectivelyDepending on the measurement environment, it can be equipped with cleaning equipment, cooling equipment and flex probes, etc., which can be better adapted to the application of industrial equipment and laboratory equipment.
EditLabasys 100 Features:
All lenses and electronics are integrated into a lightweight, easy-to-operate device;
Thanks to its modular design, it can be flexibly adapted to different working environments and measuring tasks, and the components can be replaced
The convective field disturbance is small, the sensitivity is high, and the accuracy is high
Simultaneous measurement of concentration and one- or two-dimensional velocity;
Customized equipment connection valves for installation and removal at high pressures
The efficient cleaning unit avoids the effects of electrostatic adhesion.
Labasys Control Ex is a velocity concentration tester developed for the needs of speed and concentration testing in harsh environments. Compared to Labasys 100, Labasys Control Ex is ideal for industrial installations because of its ability to perform continuous monitoring in high-temperature, high-pressure, and hazardous environments.
EditLabasys Control EX Features:
The equipment is designed for industrial applications in harsh environments;
Cooling water circulation ensures the safety of electronic components;
The equipment is CE and EX certified
Withstands 10 11 gas or 20 21 dust**;
Probe cooling, cleaning and other units can be introduced
Other features are customized.
When the particle concentration is high, there is a very strong erosion effect on the probe lens, so the strength of the probe is very high. Labasys Control EX BF is designed to measure the velocity and concentration of dense phase particle flow in the process, the probe is made of higher strength material, and the fiber optic lens is protected by a sapphire window, which is covered with an anti-reflective coating to ensure a high enough signal-to-noise ratio for the test.
Editlabasys contrOL EX BF Product Features:
The velocity of granular loose material is measured online;
The probe tip is double-sealed, and the outer layer adopts a sapphire window to ensure high leak-proof performance
0 1 Zone Gas or 20 21 Zone Dust** Protection;
The exterior of the equipment is all made of chromium-nickel steel;
Probe tip size and connection design based on customer needs;
Lyondellbasell certified velocity measurement system in the MZCR polypropylene process recirculation loop.
Chemical chain combustion process
Alstom is an expert in innovative technologies for the power industry and environmental protection, with a strong focus on clean coal combustion technology, and has developed a chemical chain combustion process that is an advanced CO2 emission reduction combustion process. In the Alstom chemical chain combustion process, the velocity of calcium salt particles in the chemical chain combustion process is measured using a custom-developed Labasys 100 flex system.
EditSpherizone polypropylene process
As the world's largest polypropylene manufacturer, Lyondellbasell has developed the state-of-the-art Spherizone process based on years of production experience. At 42 bar and 100 °C temperatures of the Spherizone process, the Labasys Control EX BF system monitors the Spherizone process, acquires and signals via post-processing software, and transmits the obtained velocity and concentration data to the control system.
Experimental measurements are shown in the figure below, where Figure 1 is a zoomed-in view of the initial start-up phase in Figure 2. The red curve shows the measurement velocity, and the green and blue curves represent the unprocessed signal from the measurement channels 1 and 2, respectively, and correlate with the polymer concentration in the downpipe.
In the initial stage, the height of the packing material and the associated concentration signal continued to rise, and the two agreed well. At this stage, the velocity pulsation is strong and there is an upward trend. The polypropylene pellets fall onto the filled pellet bed, where the packing height is lower than the position of the measuring device. Around 13:30, the concentration rises irregularly, creating a peak in polymer flow. At approximately 14:50, the packing height reaches the position of the measuring device. The reactor then reaches a steady state, as shown in Figure 2. The Labasys Control EX BF system provides real-time, detailed, and accurate measurements of the internal conditions of the Spherizon process.
In addition, the LABEDYS velocity concentration test system can also be used in the fluid catalytic cracking (FCC) process measurement system to continuously measure the local concentration and velocity of dense flow particles, providing an optimized solution for the FCC processThe best limit for high-speed powders.