An experiment-library least-squares method on on-line coal element contents analysis

A new experiment-library least-squares (experiment-LLs) method used in the neutron inelastic-scattering and thermal-capture analysis (NITA) technique for on-line coal analysis was developed, which has significantly decreased the non-linear radiation effects. In this method, sixty samples with preset elemental contents were made, from whose experimental spectra twenty single-element spectrum libraries corresponding to twenty kinds of coal were built using the least-squares method. The spectrum of the unknown sample was analyzed based on these twenty libraries to estimate its element contents. With the initial estimated result, the procedure of developing library and analysis was iterated to build a new library with the closest element contents to the unknown sample. Hence the experiment-LLs method can reduce non-linear radiation effects. The experiment-LLs method was performed on an improved coal analysis system which was equipped with a long-life 14 MeV pulsed-neutron generator, a bulk BGO detector with a temperature controller, a moisture meter and coal-smoothing device. The precisions of this system for ash content, water content, volatile content and calorific value have reached 1.0wt%, 0.5wt%, 1.0wt%, 350 kJ/kg, respectively.