A Development of Automatic Coal Petrographical Analyses for Evaluating Coking Coals

Abstract

An automatic system for measuring the distribution of reflectances of coal petrographical constituents has been developed. The system is consisted of an apparatus for microphotometric reflectances of coal and analytical programs. The apparatus is composed of a microscope, phto-cell, and mechanical scanning stage which is controlled by a computor, and measure & reflectance at 20000 to 100000points in a sample in 30 minutes to 2 horus.
The out-put data from the photo-cell are sent to the computer and transfered to absolute reflectances which has been previously compared to the standard samples, and then accumlated and stored to a disc-file of the computer. The accumlated data are retrieved at any time as the distribution of reflectances, which can be shown as a figure of numerical values.
The system possesses an ability to detect Vitrinit only, and thus one can obtain the distribution of reflectances of whole other macerals as well as of Vitrinit.
By the analytical program whic can eliminate the boundary effect of coal grains and binder and can recognize each macerals, coking properties of various types of coal and blend can be estimated.
Now the system can be used practically in the following applications, producting excellent results:
1. Making a blending plan for coke plants by estimating the coke strength of coal blends.
2. Quality inspection of purchased coal.
3. Determination of coal quality from an outcrop or boring core samples in an undeveloped coalfield.