1070-4272/01/7409-1534$25.00C2001 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 74, No. 9, 2001, pp. 1534 !1538. Translated from Zhurnal Prikladnoi Khimii, Vol. 74, No. 9,
2001, pp. 1489!1493.
Original Russian Text Copyright + 2001 by Aleksandrov, Varganov, Sarge.
PROCESSES AND EQUIPMENT
OF CHEMICAL INDUSTRY
Design and Study of Gas Calorimeter for Absolute
Measurements of the Combustion Heat of Natural Gas
Yu. I. Aleksandrov, V. P. Varganov, and S. Sarge
Mendeleev Russian Research Institute of Metrology, State Unitary Enterprise, St. Petersburg, Russia
Physicotechnical Institute, Braunschweig, Germany
Received April 28, 2000; in final form, June 2001
Abstract-A novel burning calorimeter design based on a heat pipe is presented. A circuit for automated
control over operation of the proposed device is considered. The stability of the results is assessed. Several
accessory parameters affecting the reproducibility of measurement results are evaluated. One of recent designs
of the KTT-7 calorimeter, based on a thermosiphon, is analyzed. The uncertainty in heat power measurements
on KTT-7 is evaluated.
A new isothermal method, described in detail in
, was used in designing a gas calorimeter. It was
necessary to design such a heat pipe that could ac-
commodate a gas burner and ensure continuous re-
moval of water formed in gas burning. The desire
to diminish the error in measuring the heat energy
released in gas combustion to a level not exceeding
0.1% imposed additional requirements to the calorim-
eter design and choice of measuring equipment. To
achieve complete utilization of heat released in gas
burning and its transfer with minimum loss to the
condensation zone, a heat pipe was developed in the
form of a thermosiphon presented in Fig. 1.
Gas burner 1 is situated within heat exchanger 2.
The heat exchanger is close in its design to the known
combustion chambers used in industrial gas calorim-
eters. The heat exchanger is situated in the heating
zone of thermosiphon 3 and is submerged in the
working liquid, for which freon was chosen.
Control heater 4 is also submerged in freon whose
boiling temperature is measured with thermometer 5
placed directly in the bulk of the heat-transfer agent.
Battery 6 of Peltier elements is situated at the opposite
end of the thermosiphon, with the Peltier elements
mounted within a special hollow forming the conden-
sation zone. The temperature of the heat-transfer agent
The choice of Freon-11 as working liquid was primarily made
for the following two reasons. First, it is incombustible, which
is of no small importance when employing a gas burner.
Second, this substance happily combines a boiling point close
to the standardized 25oC and small, compared with that of
water, heat of vaporization.
is measured with thermometer 8 whose signal is em-
ployed by the control circuit.
All specific design features of the calorimetric unit
were aimed (i) to reduce to the maximum possible
extent the heat loss both in the heat carrier evapora-
tion zone and in the condensation zone and (ii) to
Water from thermostat
Water to thermostat
Gas + argon
Fig. 1. General view of the calorimetric unit.