GB/T 33304-2016 in English

Standard Background and Technical Evolution

This standard was drafted in accordance with the rules of GB/T 1.1—2009, proposed by the China Coal Industry Association, and managed by the National Coal Standardization Technical Committee. The main drafting units include Beijing Coal Chemical Research Institute of China Coal Research Institute, Xi'an Thermal Engineering Research Institute Co., Ltd., etc.

As a mature test method, thermogravimetric analysis has been widely used in the study of coal combustion characteristics. The formulation of this standard further standardizes the application process of this method to ensure the consistency and accuracy of the experimental results.

Terms and Definitions

Instruments and test steps

Thermogravimetric analyzer is mainly composed of a heating furnace, a temperature controller, a thermobalance and a recorder. Its key performance includes:

• Heating range: room temperature to 1200℃
• Heating rate control accuracy: ±0.1℃/min
• Thermobalance sensitivity: 0.01mg

Test steps:

1. Sample preparation: Prepare general analysis coal samples according to GB 474, with a particle size of less than 0.2mm.
2. Instrument preparation: Preheat for 30 minutes, calibrate the mass and calibrate the temperature.
3. Baseline test: Repeat the measurement twice, and the difference in mass signal shall not exceed ±0.05mg.
4. Combustion test: Weigh (10±1)mg sample and record the TG-DTG curve.

Characteristic indicators and result analysis

According to the thermogravimetric curve and the differential thermogravimetric curve, the following characteristic indicators are determined:

• Ignition temperature (Ti)
• Burning temperature (Tf)
• Maximum burning rate (vp)
• Maximum burning rate temperature (Tp)
• Average burning rate (v)

Formula:v = β × (αi - αf) / (Tf - Ti)

Precision and implementation suggestions

Implementation suggestions:

• Prepare samples strictly according to the standards to ensure particle size and weighing accuracy.
• Calibrate instruments and equipment regularly to ensure the accuracy of experimental results.
• Pay attention to the control of test environment conditions, especially the requirements for atmosphere flow and dew point.