Title: Studies on Determination of Nitrogen in Coke Statisitical Analysis of Round-Robin Study
Abstract: Inyerlaboratory experimental work has been undertaken at the 30 different laboratories to study the following items on the determination of nitrogen in coke.1) Whether there occuers the significant difference between analytical values obtained by Semi-micro Kjeldahl methods using a catalyst mixture including selenum and that excluding it.2) Whether the difference of analytical values is recognized between in Semi-micro Kjeldahl method and Semi-micro Gasification method. The comparative study of instrumental method were also undertaken for a reference.The following conclusions were derived from the above experiment.1) Significant bias between results obtained using two kinds of catalyst mixture (including or excluding selenum) in Semi-micro Kjeldahl method can not be observeed if the digestion is carried out carefully.2) The analysis can be carried out more quickly and more precisely in Semi-micro gasification method than in Semi-micro Kjeldahl method.This is recognized to be because the complete digestion of coke is relati-vely difficalt in Semi-micro Kjeldahl method.3) It is considered that the difference of analyical values on coke suffered in high temperature between in Semi-micro Kjeldahl method and in Semi-micro gasification, derives from reason below.a) Final titration is carried out in the condition of still insufficient digestion because the development of graphitization makes the digestion difficalt in Semi-micro Kjeldahl method.b) The loss of nitrogen during the digestion usually taking a long time leads to the loweering of observed values.c) As another possibility, there is not denying the existance of nitrogen which is not completely decomposed by the Semi-micro Kjeldahl method when coke suffered in high temperature is analysed.