Study On The Effect Of The Free Moisture On The Net Calorific Value Under The MCNP In The Neutron Coal Analysis

With the high developing pace of industry, the demand for coal is becoming larger andlarger as one of the most important energies in China’s industry and people’s lives. In order toincrease its utilization rate, the very first thing is to testify the quality of coal, especially itschemical composition and net calorific value. At present, chemical analysis is often employedto testify the quality of coal, which contains a series of processes, such as sampling, breakingdown, weighting, drying and measuring and it needs very long time. However, the promptgamma neutron activation analysis takes shorter time and can testify different elements at thesame time, having become one effective way of analysis in the coal industry. The neutrontestifying of coal quality lies in that the nucleus action has occurred between the neutronbeing testified and atomic nucleus of the element in the coal sample, which radiatesgamma-rays. It is according to the gamma-rays that the elements and their contents can becertain, based on which, the industrial value of coal is computed and the whole process willonly cost twenty minutes.The paper introduced the theory and current development status gamma neutronactivation analysis, and based on the neutron testifying of coal quality, the research employedMCNP to analog compute the influence of the free moisture on the net calorific value. Whenthe model is fixed, the research simulated the change of free moisture from0.1kg to1kg infour coal samples with different carbon contents. When the value of free moisture changedevery0.1kg, a group of data would be collected, which analyzed the numbers of gamma raysthat character C, H and O elements and the change of net calorific values. When thesimulated results were compared with the theoretical values, these following findings havebeen investigated. As free moisture increases, the difference between the numbers of gammarays that character C, H and O elements and their net calorific values that got in thesimulation, and the theoretical values would became larger and larger. As a result, whenemploying the method of neutron testifying of coal quality, the contents of free moisturesshould be controlee so as to prove the measured accuracy.