DL/T 520-2025 in English
VALIDTechnical Guidelines for Coal Testing Laboratories in Thermal Power Plants
- Issued on:2025-06-30
- Implemented on:2025-12-30
- File Format:PDF
- Delivery:Via email within 1~3 business days
$277.00
| Standard No: | DL/T 520-2025 |
| Document status: | VALID |
| Title in English: | Technical Guidelines for Coal Testing Laboratories in Thermal Power Plants |
| Title in Chinese: | 火力发电厂煤炭检测实验室技术导则 |
| Language: | English |
| File Format: | Electronic (PDF) |
| Delivery: | Via email within 1~3 business days |
| Issued on: | 2025-06-30 |
| Implemented on: | 2025-12-30 |
| ICS Classification: | 71.040.10-Chemical laboratories. Laboratory equipment |
| Chinese Classification: | D21-Coal analysis methods |
| Professional Classification: | DL-Electricity |
| Related Keywords: | coal testing laboratories
coal testing incoming coal testing items technical features incoming coal thermal power plants |
Introduction
Standard Revision Background and Technological Evolution
DL/T 520-2025, "Technical Guidelines for Coal Testing Laboratories in Thermal Power Plants," is a comprehensive upgrade of the 2007 version of the standard. This revision fully reflects the achievements of nearly 20 years of development in coal testing technology. The standard's title has been expanded from "Incoming Coal Testing" to "Coal Testing," and the testing scope now covers all samples in the entire process, including incoming coal, incoming coal, pulverized coal, fly ash, and slag, reflecting the comprehensive requirements for fuel quality management in modern thermal power plants.
Technical evolution is primarily reflected in three aspects: a significant increase in automation, with the addition of technical specifications for robotic testing systems and automated sample preparation equipment; a comprehensive improvement in informatization, with the addition of requirements for data management systems for sampling and processing; and a more comprehensive quality control system, with the introduction of advanced management methods such as coal sample encryption and interim verification.
Testing project system architecture
The standard constructs a complete coal testing project system for thermal power plants, which is divided into three categories according to the test objects:
| Testing categories | Core testing items | Optional testing items | Technical features |
|---|---|---|---|
| Incoming coal testing | Sampling, total moisture, industrial analysis, total sulfur, calorific value | Elemental analysis, ash fusibility, grindability index | Key indicators for quality acceptance |
| Incoming coal testing | Sampling, total moisture, industrial analysis, total sulfur, calorific value | Elemental analysis, ash fusibility, grindability index | Basic data for combustion optimization |
| Other tests | Coal powder fineness, fly ash and slag combustibles | Related extended test items | Operation efficiency monitoring indicators |
The setting of test items reflects the concept of whole-process quality control, forming a complete testing chain from fuel acceptance to combustion process monitoring and then to emission analysis.
Technical Requirements for Laboratory Construction
The standard sets out detailed requirements for laboratory hardware configuration, focusing on the following:
6.1 Functional Zoning
The laboratory should have core functional areas such as a sample preparation room, a sample storage room, a weighing room, a high-temperature chamber, a calorific value measurement room, and automated industrial and elemental analysis rooms. An ash fusion characteristics test room, a gas cylinder room, and a grindability index measurement room are optional. Functional zoning reflects the specialized requirements of the testing process.
6.3 Area Allocation Standard
Automated equipment places higher demands on laboratory space: sample preparation rooms equipped with automated sample preparation equipment must have an area of at least 200 square meters, sample storage rooms equipped with automated sample storage equipment must have an area of at least 50 square meters, and laboratories equipped with robotic testing systems must have an area of at least 200 square meters. These area requirements reflect the trend toward larger-scale testing equipment.
6.9 Environmental Control Requirements
All laboratory rooms should be equipped with temperature and humidity monitoring devices to maintain a temperature range of 15-30°C and a humidity range of 30-70% RH. Special areas, such as robotic laboratories, require a 24-hour temperature difference of no more than 4°C, and calorimetry rooms require a temperature fluctuation of no more than 1°C between measurements. Strict environmental control is essential for ensuring the accuracy of test results.
Technical Specifications for Instruments and Equipment
The standard sets clear technical requirements for various types of instruments and equipment, with key equipment including:
7.2 Mechanical Sampling Equipment
Mechanical sampling equipment should comply with the requirements of GB/T 30730, must have bypass openings for primary sub-samples and each level of retained samples, and be equipped with weighing capabilities and a precision test mode. The equipment should be free of substantial bias, and total water loss should comply with the requirements of DL/T 747. Sampling precision requirements: Coal entering the factory must comply with GB/T 19494.1, and coal entering the furnace must comply with DL/T 567.4.
7.4 Automatic Sample Preparation Equipment
Automatic sample preparation equipment must comply with GB/T 30731 and be capable of preparing total moisture coal samples, inventory samples, and general analytical test samples. Strict technical specifications are required: sample loss rate ≤ 2.0%, external moisture adaptability not less than 8%, and average sample interval ≤ 40 minutes. The equipment must be equipped with cross-contamination prevention capabilities, and sample preparation precision must comply with GB/T 19494.2.
7.6 Robotic Testing System
The robotic testing system is a new addition to this standard, requiring testing to include at least industrial analysis, total sulfur, and calorific value, with elemental analysis optional. The system should automate the entire sampling, mixing, weighing, and testing process, with a full analysis of 60 samples completed in no more than eight hours. Technical requirements emphasize the absence of substantial bias in test results and precision that meets the standards for each method.
| Equipment type | Core technical requirements | Performance indicators | Compliance with standards |
|---|---|---|---|
| Mechanical sampling equipment | No substantial bias, anti-clogging design | Total moisture loss meets the standard, precision meets the standard | GB/T 30730, DL/T 747 |
| Automatic sample preparation equipment | Anti-cross contamination, moisture adaptability | Loss rate ≤2.0%, sampling interval ≤40min | GB/T 30731, GB/T 19494.2 |
| Robotic Testing System | Fully automatic testing, coded identification | 60 samples/8 hours, no substantial bias | Standards for various methods |
Sample Collection and Preparation Data Management System
Chapter 8 of the standard systematically specifies the requirements for a sample collection and preparation data management system for the first time, reflecting the trend of informatization in testing:
8.1-8.2 The system should have the function of collecting information such as sample collection and preparation plans, equipment operating parameters, and sample weighing data, as well as complete process management such as test process data collection, result review, and report generation.
8.3-8.4 Supports direct connection to test instruments for data collection, automatically collecting weighing data through the balance serial port to ensure the accuracy of the data source.
8.5-8.8 Implement advanced features such as automatic parallel sample review, instant test order generation, multi-level review processes, and custom report templates, and establish a complete test data ledger system.
Laboratory Technical Management Regulations
Chapter 9 specifies the core technical requirements for laboratory operations management:
9.1 Coal Sample Encryption and Coding Management
Implement full-process coal sample encryption and coding. Encrypted information for incoming coal includes the supplier, source, and type of coal, while encrypted information for incoming coal includes the furnace type and shift. Encrypted management ensures the objectivity and fairness of test results.
9.4 Instrument and Equipment Quality Control
Establish a complete instrument and equipment quality assurance system: regular verification and calibration of measuring instruments, regular functional inspections of non-measuring instruments, and inspections of critical equipment during operation. Regular performance inspections of mechanical sampling equipment and automatic sample preparation equipment ensure continued compliance with requirements.
9.7 Laboratory Quality Control System
Establish quality control procedures for mechanized coal sampling and preparation equipment and test results, and conduct reference material testing, comparison testing, and proficiency testing. Implement a Level 2 or higher audit system and regularly retest stored coal samples to ensure the reliability of test results.
Implementation Recommendations and Outlook
Based on the technical requirements of DL/T 520-2025, the construction of coal testing laboratories in thermal power plants should focus on the following:
Automation Upgrade Path
Prioritize the configuration of automatic sampling equipment and sampling and preparation data management systems, and gradually promote the application of robotic testing systems. When selecting automated equipment, focus on technological maturity and ease of maintenance to ensure long-term stable operation.
Quality Control System Construction
Establish a comprehensive interim verification procedure and regularly conduct performance verification of mechanical sampling and automatic sampling equipment. Use the methods provided in Appendix A and B to conduct preliminary verification of precision and bias to promptly detect changes in equipment performance.
Personnel training and certification
Strengthen professional and technical training for samplers, sample preparers, and laboratory technicians to ensure they hold valid on-the-job operation certificates. Focus on training in modern testing skills such as automated equipment operation and maintenance, data system usage, and quality control methods.
Standardized operating procedures
Develop detailed standardized operating procedures covering the entire process of sampling, sample preparation, testing, data review, and report issuance. Pay special attention to timeliness requirements, such as the time interval for measuring various indicators of general analytical test coal samples shall not exceed 8 hours.
The implementation of DL/T 520-2025 will significantly improve the level of coal testing technology in thermal power plants, provide reliable technical support for fuel quality management, optimized boiler operation, and environmentally friendly emission standards, and promote the industry to develop in the direction of automation, informatization, and standardization.
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