US 5,816,705 A · Measuring heating value of a gas using flameless combustion

Abstract

The heating value of a sample gas is calculated by a microcontroller (12) from the heating value of a reference gas, and from flow ratios and power levels determined as the gas is combusted by a flameless combustion process. The combustible gas is mixed with a combustion supporting gas, such as air, and flowed to a body of material (26, 52) which is heated to a temperature sufficient for oxidation of the gas mixture. The size of spaces in a first embodiment of a heater device (9, 11, 25, 26) and in a second embodiment of a heater device (50) are limited to prevent formation of an open flame. In a preferred "lean mixture" embodiment, the gas-air mixture of the reference gas, and the gas-air mixture of the sample gas, respectively, are each adjusted until a selected power level of combustion at a temperature lower than the point of stoichiometric combustion is reached. In a second, "rich mixture" embodiment, the gas-air mixture of the reference gas, and the gas-air mixture of the sample gas, respectively, are each adjusted from a "rich mixture" to reach a point of stoichiometric combustion. Based on flow rates and the selected power ratio, the heating value of the sample gas is calculated by the microcontroller (12) and output to a visual display or other output device.

Claims46

Dependent claims

A method of measuring heating value of a combustible gas, the method comprising:

heating a body of material to a temperature sufficient for combustion of the combustible gas and quenching any flame resulting from said combustion;
flowing a first mixture of a reference gas having a known heating value and a combustion supporting gas into contact with the heated body of material to cause combustion of the reference gas;
varying the first mixture of the reference gas and the combustion supporting gas to obtain a changing combustion power;
detecting at least one molar flow rate of the reference gas supplied to the first mixture and corresponding to a first occurrence of at least one selected combustion power level of the changing combustion power;
flowing a second mixture of a sample gas and the combustion supporting gas into contact with the heated body of material to cause combustion of the sample gas;
varying the second mixture of the sample gas and the combustion supporting gas to obtain a second occurrence of the changing combustion power;
detecting at least one molar flow rate of the sample gas supplied to the second mixture and corresponding to a second occurrence of the selected combustion power level for said second occurrence of the changing combustion power;
and
calculating the heating value of the sample gas in response to a ratio of the reference gas molar flow rate and the sample gas molar flow rate for the reference gas and the sample gas, respectively, and in response to the known heating value of the reference gas.

6 more elements

Dependencies are inferred from the claim text.

Measuring heating value of a gas using flameless combustion

Life of this patent

Measuring heating value of a gas using flameless combustion

Life of this patent

Abstract

Claims46