Development a modified crossing point temperature (CPTHR) method to assess spontaneous combustion propensity of coal and its chemo-metric analysis

Abstract Spontaneous combustion of Indian coals was investigated using sponcomb rig at University of Nottingham, UK to assess their susceptibility. In the present study authors have used eleven coal samples collected from the Jharia coalfield (JCF), India. Both thermal as well as gas profiles from sponcomb rig were studied critically to develop a modified crossing point temperature to assess the spontaneous combustion propensity of coal. The product of combustion gases (CO, CO 2 , CH 4 , and H 2 ) emitted from sponcomb rig within the temperature range between ambient and 300 °C of these coal samples were studied. The initial product of combustion gas i.e. CO followed by H 2 indicates propensity towards oxidation of coal in laboratory condition for Jharia coalfield. The temperatures at which CO and H 2 releases in the level of 50 ppm (T CO50 , T H250 ), crossing point temperature of coal (CPT CT ) (temperature of coal and bath temperature is same) and modified crossing point temperature of coal (CPT HR ) (temperature where dT/dt is equal to 2.0 o Cmin −1 because heating rate is double of programme temperature 1 o Cmin −1 ) determined from sponcomb rig categorises the coal as per their propensity to spontaneous combustion. The results of these methods have been compared with other standard method i.e. crossing point temperature method – India, which is widely adopted in Indian regulatory bodies to verify the suitability of this method.