Apparatus and Method for Measuring the Heat of Gases
Patent Reference:
PCT/CZ03/00065, WO2004/048954 A1
US Appl. No. 10/533,171 filled on the 29th, April, 2005
EU Patent Appl. No. 03769176.3-2204
Author: Jiří Ševčík
Owners: Jiří Ševčík and RWE Transgas Net
Patent describes sensor for direct measurement of the heat of combustion. Measurement is maintained through the controlled temperature of the sensor, which is a function of the total energy input provided by an electrical heating Qel and the heat produced by combustion of natural gas Qng. Thus the measured change in the electrical heating
ΔQel is inversely proportional to the change in the heat of combustion (ΔQng) of any combustible component in the investigated gas stream.Instrument based on the given IP is suited for continuous, on-line and precise measurement of heat of combustion of natural gas and other combustible gas streams like biogas, conversion gas, cook gas, process gases, etc. Thus it allows an effective mixing of different gas streams of a different heat of combustion to produce a gas stream with requested value of the heat of combustion.
An increasing demand on an alternative energy sources is boosting technology development in biogases. Crucial problems are linked with a changing value of the heat of combustion within a production cycle and a large number of production sites connected to gas supply system. Nowadays there are not measuring systems available for on-line process control and mixing of biogases with natural gas.
It is expected that there will be created up to 6,000 biogas producing sites in Germany up to year 2015. All of them have to be connected to natural gas supply system. Thus for all of them will be a must to know heat of combustion of the feed gas to provide correct mixing. A similar situation will be in all other technology developed countries.
A prototype based on this IP has been developed and tested on the natural gas pipeline system between Russia and Germany, in the Czech Republic. Promising results have been obtained. Repeatability of the heat of combustion was 0.13% from 33,800 measurements over a period of 15 month, actual value of the heat of combustion was updated each 2 seconds, changes in the range of 4.9 MJ/m3 is correctly measured, for calibration pure methane can be used.