Method for detecting moisture in coal by vacuum heating

Abstract

The invention relates to a method for detecting the moisture in coal by vacuum heating. Currently, no method for detecting moisture in coal with simple operation, high determination efficiency and high determination result precision is available. The method comprises the following steps: weighing a coal sample having a certain mass in a vacuum-heat drying device, vacuumizing the vacuum-heat drying device, and heating the coal sample in a heat conduction and / or heat radiation mode for drying so as to quickly evaporate moisture of the coal sample and achieve the aim of quickly drying. By adopting the method, the boiling point of free moisture in the coal sample is greatly reduced in a vacuum environment, vaporized steam can be quickly extracted to form a negative pressure state around the coal sample, a great humidity gradient is formed between inner layer and outer layer of coal sample particles and between the surface and surrounding mediums, and the vaporizing speed is accelerated; and the coal sample is dried to a constant mass under set vacuum degree and temperature, and the mass percentage of moisture in the coal can be calculated according to the lost mass after the coal sample is dried. The method has simple operation, high detection efficiency and high detection result accuracy.

Description

technical field [0001] The invention relates to a method for measuring moisture in coal by vacuum heating, which belongs to a coal detection method and is applicable to various types and varieties of coal. The general analysis test of mm is used for the determination of moisture in coal samples, and is also applicable to the drying of the above-mentioned coal samples. Background technique [0002] Young bituminous coal and lignite are known to be susceptible to oxidation. For this reason, when measuring the moisture content of lignite, the national standards GB / T211 and GB / T 212 specifically require that nitrogen (inert gas) be fed into the blast drying oven. Ordinary blast drying to measure the full moisture of lignite coal samples and general analysis of the moisture content of test coal samples needs to be fed with nitrogen and heated to (105-110) °C; when other coal samples are measured, the drying time is slightly different. Into nitrogen, the others are the same as l...

AI Technical Summary

Problems solved by technology

For easily oxidized coal, coal samples that are air-dried as part of the determination of total moisture, and coal samples used to measure parameters / items such as calorific value, cohesiveness, and expansion properties, it is not possible to dry them at a temperature higher than 40°C. To a certain extent, it affects the accuracy of the determination

Although there are also other methods for measuring moisture in coal now, as the publication date is December 02, 2015, and the publication number is CN105115852A in the Chinese patent, a method for determining the highest intrinsic moisture of coal is disclosed, but the operation of the method more complex

At present, there is no method for the determination of moisture in coal with simple operation, high measurement efficiency and high accuracy of measurement results.