Gas Calorimetry

Abstract

IN the recent report of the Departmental Committee appointed to consider the question of the control of the gas supply of the metropolis, a proposal was made that the calorific power of the gas should be regularly determined, thus recognising the growing importance of the heating value of gas as distinguished from its illuminating power. The use of gaseous fuel both for heating and power purposes having led to a demand for exact gas ealorimetry, several types of calorimeter have come into use. In those of the Junker type, the gas is burned at a measured rate, and the products of combustion are cooled down by a stream of water also flowing at a known rate, the ingoing and outgoing temperatures of which can be accurately measured. In spite of the difficulties of securing accurate measurements of the rate of flow of gas and water, on account of the speed with which consecutive determinations can be carried out instruments of this type are mostly used by gas engineers. Their chief defect is want of portability, and as an alternative a sample of the gas is frequently analysed, and the calorific value deduced from the results of the analysis. Apart from the difficulty of exactly determining the constituents of such a complicated mixture as coal gas, this method implies that the exact calorific value of each substance present is accurately known, and this, unfortunately, is far from being the case.