Solidat 3D Radar Level Meter: Features and Applications - A Case Study of a Coal Plant

Abstract

This paper focuses on 3D radar level meters in level measurement technology, explaining their application principles and comparing the core features of traditional radar and 3D radar. It highlights the practical application effects of Solidat's 3D radar level meter products in coal plants, providing a reference solution for level measurement challenges in coal plants.

Keywords

Level gauge; 3D radar; coal plant; material level measurement; dust environment

1. Overview

With the accelerated intelligent transformation of the coal industry, coal plants have significantly increased demands for precision, stability, and smart solutions in material level measurement. Traditional methods like manual inspections, ultrasonic level meters, and conventional radar level meters face notable limitations: Manual inspections are inefficient and unsafe, making real-time monitoring of silo dynamics challenging; Ultrasonic level meters are prone to coal dust interference, resulting in severe signal attenuation and large measurement errors; While conventional radar level meters partially mitigate dust interference, they still struggle to achieve comprehensive coverage in complex silo conditions (such as arching, material deviation, or dead zones), often leading to misjudged material levels that disrupt production scheduling and inventory management.

Among various level measurement technologies, 3D radar level meters have emerged as a game-changer. By leveraging multi-beam scanning and 3D imaging capabilities, they overcome the spatial limitations of traditional methods to clearly visualize material distribution in silos. These systems not only provide precise level measurements but also enable real-time monitoring of material volume, mass, and pile morphology. As the go-to solution for intelligent level measurement in coal plants, they effectively bridge the gap left by conventional technologies in complex silo environments.

2. Features of radar technology

2.1 Characteristics of traditional radars (including microwave radar and conventional guided wave radar)

Single measurement dimension: It can only obtain the material level height data, but cannot perceive the horizontal distribution of materials in the silo. Facing the common "material deviation" and "arch" phenomenon in the coal silo, it cannot identify the actual empty volume in the silo, which is easy to cause deviation in inventory calculation.

Limited Dust Interference Resistance: Microwave radar signals are prone to scattering and attenuation in high-concentration coal dust environments. When dust concentration exceeds 50g/m³, signal reflection intensity drops dramatically, significantly compromising measurement accuracy. While conventional guided wave radar systems show less susceptibility to dust interference, their probes are susceptible to coal dust adhesion. Prolonged use leads to signal drift caused by accumulated deposits, necessitating frequent cleaning and maintenance.

Limited coverage: Traditional radars are mostly single-beam or narrow-beam designs, which can only measure a "point" or "line" within the silo and cannot fully capture the overall material level status of the silo. For large coal silos with a diameter of more than 8 meters, multiple devices need to be combined and installed to achieve preliminary coverage, which increases the equipment cost and debugging difficulty.

2.2 Features of 3D Radar

3D Panoramic Imaging: Utilizing multi-beam array technology, this system simultaneously emits 20-30 high-frequency radar beams to cover both the 360° horizontal area and 0-90° vertical angle within the material silo. Through signal stitching and data reconstruction, it generates real-time 3D images of the material inside the silo, clearly displaying the stacking patterns, arching positions, material deviation degrees, and blind spots in empty silos. This effectively resolves the traditional radar's limitations of "invisibility and imprecise measurement".

Dust and harsh environment resistance: The 3D radar employs specialized signal modulation technology, emitting signals with 5-10mW power (5-10 times higher than conventional microwave radars). Its optimized wavelength design specifically matches coal dust particle characteristics, enabling penetration through high-concentration dust (up to 100g/m³) while minimizing signal scattering loss. Featuring IP67-rated protection, the equipment withstands extreme temperatures (-40°C to 80°C) and corrosion, making it ideal for coal plant silos where humidity, dust, and temperature fluctuations are common challenges.

Multi-parameter synchronized measurement: In addition to precise material level height measurement (accuracy ±5mm, resolution 1mm), it can also calculate material volume (error ≤2%) and mass (combined with coal bulk density preset function) based on 3D images, automatically generating inventory reports without manual conversion. This provides direct data support for coal plant inventory management and production scheduling, reducing manual statistical errors.

Low Maintenance and Intelligent Diagnosis: The device features no mechanical moving parts, eliminating issues like material buildup and mechanical wear in traditional guided wave radar probes. Annual maintenance is reduced to 1-2 times. With built-in intelligent diagnostic functions, it monitors real-time operational status (including signal strength, beam integrity, and communication links). When signal anomalies or equipment failures occur, it automatically sends alerts to the central control system, significantly reducing downtime risks.

Adapt to complex silo structures: Supports measurement of coal silos with various shapes including circular, square, and rectangular. Through parameter settings, it can accommodate obstacles such as ladders and mixing devices inside the silo, automatically filter interference signals, and does not require additional shielding devices. It meets the measurement needs of various coal plant silos (such as raw coal silos, refined coal silos, and coal slurry silos).

3. Principles of traditional radar and 3D radar

3.1 Traditional radar

Traditional microwave radar systems operate by emitting a single high-frequency (GHz range) electromagnetic beam. They calculate material level height using the propagation time of reflected signals (based on the electromagnetic wave's speed, equivalent to the speed of light) through the formula: Material Level Height = (Electromagnetic Wave Propagation Speed × Reflection Time) / 2. However, in coal plant silos, high concentrations of coal dust cause multiple scattering of electromagnetic waves. Part of the signal is absorbed by dust particles, resulting in effective signal energy returning to the receiver antenna being merely 0.5%-1% of the transmitted energy. This often leads to "no reflection signal" or "false reflection signal" issues. While conventional guided wave radar systems use waveguides (steel cables/rods) to reduce dust interference, their signals propagate only along the waveguide path. This limitation prevents horizontal coverage of silo areas, and material accumulation on the probe rod can alter waveguide impedance, causing measurement errors.

3.2 3D Radar

The 3D radar operates based on multi-beam time-domain reflectometry (Multi-beam TDR) and 3D data reconstruction technology, with the core principles as follows:

Multi-beam transmission and reception: The radar antenna array simultaneously emits multiple high-frequency (24GHz) electromagnetic beams. Each beam scans the material surface in the silo at preset angles (lateral spacing of 1°-2°, longitudinal coverage of 0-90°), creating a "surface-like" coverage. The receiving antenna synchronously captures the reflected signals from each beam, recording the propagation time and signal strength of each beam group.

Signal Processing and Interference Filtering: Utilizing specialized algorithms, the system processes multiple reflected signals to filter out interference from coal dust scattering and object reflections (based on signal strength thresholds and beam consistency analysis), while retaining valid surface reflection signals. Simultaneously, it calculates the three-dimensional coordinates (X, Y, Z axes) of reflection points within the silo using beam angle parameters.

3D Image Reconstruction and Parameter Calculation: The system first merges 3D coordinates from all valid reflection points to generate a 3D point cloud model of the material within the silo. Using image rendering technology, it creates an intuitive 3D visualization. Based on this model, the system automatically calculates the maximum and average material level heights, while determining the material volume through an integration algorithm. By combining these calculations with predefined coal density parameters (e.g., raw coal density 1.3-1.5t/m³), the system ultimately outputs accurate material quantity data.

4. Solidat 3D Radar Level Meter: Introduction and Applications

4.1 Core Technical Features of the Product

Solidat, a leading provider of industrial automation equipment, has developed the 3D radar level gauge (Model: SLDL5300 Series) to meet the material level measurement requirements of coal plants, featuring the following core technical characteristics:

Measurement performance: Measurement range 180°,360° (suitable for small and medium to large coal yard), volume accuracy ±0.5%, distance accuracy 1mm, support density setting (0.5-3t/m³), meet the measurement needs of different coal types.

Communication and data output: Supports Ethernet industrial, AUTBUS, 485 and other communication modes, and can output material level height, volume, mass, 3D image data (support BMP/JPG format export), and is compatible with coal plant central control system data interface.

Installation and commissioning: The top-mounted installation (flange connection, compatible with DN50-DN200 flanges) features small installation holes, eliminating the need for extensive modifications to the silo. Commissioning is completed via touchscreen or remote computer.

Imaging effect: high-speed data processing and analysis, data processing is quickly and automatically completed by the computer, simple 3D graphics operating system to achieve three-dimensional reproduction of the measured target, and can carry out graphics rotation, translation and local enlargement and other interactive operations, the measurement results are clear at a glance.

4.2 Coal Plant Application Case

Take a large state-owned coal plant (annual capacity of 5 million tons) as an example. The plant has 8 raw coal silos (diameter 10m, height 25m) and 4 refined coal silos (diameter 8m, height 20m). The previous measurement using ordinary microwave radar level meter has three problems:

The coal dust concentration in the raw coal silo is high (60g/m³ on average), and the microwave radar signal attenuation is serious. About 30% of the time, effective material level data can not be obtained, so manual inspection is required, which has the risk of falling from high altitude;

Coking coal silos often experience 'material imbalance' (uneven material levels on one side). Conventional radar systems, which only measure single-point data, cannot detect such imbalances. This results in a 70% utilization rate of the silo's actual capacity, frequently causing' full silo alarms despite remaining empty space'.

Inventory statistics require manual estimation based on the height of material levels and the volume of material bins in each warehouse. It takes 2-3 hours per time, and the error rate is 5%-8%, which affects the procurement plan and production scheduling.

At the beginning of 2024, the plant introduced 83D radar level meters (6 for raw coal silos and 2 for refined coal silos), and the application effect was significantly improved:

Improved measurement stability: 3D radar has strong penetration ability of high concentration coal dust, and the effective signal acquisition rate is increased from 70% to 99.5%. No manual inspection is required in the warehouse, which reduces the labor cost by about 120,000 yuan per year and eliminates the safety hazard of high-altitude work;

Solving the problem of material deviation identification: The 3D image displays the material distribution in the cleaned coal bin in real time. When the material deviation occurs (the difference between the two sides of the material level is more than 1m), the system will automatically alarm and guide the operators to adjust the feeding position. The utilization rate of the bin capacity is increased to 90%, which can store about 1500 tons of cleaned coal more every year and increase the economic benefit by about 1.2 million yuan;

Intelligent Inventory Management: The system automatically calculates coal quantities in each warehouse and generates inventory reports with data updates every minute. This reduces inventory statistics time from 2-3 hours to 10 seconds, while lowering error rates below 2%. It provides precise data support for coal plant procurement planning (e.g., determining raw coal purchase quantities based on inventory consumption rates) and production scheduling (e.g., adjusting coal washing output according to cleaned coal inventory levels), effectively minimizing production disruptions and raw material waste caused by inventory misjudgments.

In addition, the low maintenance characteristics of the 3D radar level meter also significantly reduce the operation and maintenance costs of the coal plant: the equipment has only been cleaned once in the past year, and there is no record of failure shutdown. Compared with the traditional radar (which needs to be maintained once every 3 months on average), the annual maintenance cost is reduced by about 80,000 yuan.

5. Conclusion

Solidat 3D Radar Level Counters leverage cutting-edge technologies including 3D imaging, multi-parameter measurement, and robust anti-interference capabilities to effectively address core challenges in coal plant material storage measurement. These include severe dust interference, complex material level configurations, and inventory tracking difficulties. The system not only enhances measurement accuracy and stability but also drives intelligent upgrades in coal plant inventory management and production scheduling. The SLDL5300 3D Measurement System employs a narrow, high-penetration beam that adapts to complex working conditions, remaining unaffected by harsh environments such as high temperatures, dust corrosion, steam, rain, or fog. With excellent cost-performance ratios, it is widely applicable for measuring solid materials in various storage locations including silos, containers, and bulk solid material warehouses. In the context of the coal industry's intelligent transformation, Solidat 3D Radar Level Counters provide reliable and efficient level measurement solutions with broad application prospects. These systems are expected to further adapt to scenarios like unmanned coal plant silos and smart warehousing systems, offering stronger support for the digital development of the coal industry.