| 摘要 |
<p>The thermal power P is determined by passing the gas through a flowmeter (7) of standardized thermal mass, receiving informa from the flowmeter, calculating the Wobbe index for the gas, and calculating the lower (or upper) thermal power by multiplying t received information by the lower (or upper) calorific value of the reference gas and by a refining function using the gas Wobbe index The flowmeter is calibrated for the reference gas. The thermal power of the gas is regulated to a power P0, and the flow is regulated to a value Q0 equal to (1+x)P/K where x is the excess of fuel and K is a constant depending on the fuel. The reference gas is methane, propane or butane. The fuel gas is a natural gas and the refining function is f(W) = aW+b where a is 0.035-0.050 and b is 0.30-0.45. A combustion meter is used to determine the Wobbe index of the gas, or the Wobbe index is calcul from the results of the chemical analysis of the gas. Independent claims are also included for the following: (i) a device for carrying out this process, containing a flowmeter (7), a means (6) of determining the Wobbe index of the g means (20) of receiving the information from the flowmeter and the means of determining the Wobbe index, and means of calculatin the thermal power; and (ii) a method of characterizing a flowmeter using a linear equation FGC/GC0(PCGC/PCGC0) = aWGC + b, where a and b are coefficients which are calculated using the above equation. FGC/GC0 is the correction factor to be applied to the flow rate prov by the flowmeter for a known flow of reference gas and PCGC/PCGC0 is the ratio of thermal power between the fuel gas and the reference gas. The coefficients are calculated by calculating or measuring the Wobbe index, a thermal power and the correction factor for a statistically significant number of constituents of the fuel gas. a and b are determined by plotting the product XG FGCi/GC0(PCGCi/PCGC0) and carrying out a linear regression.</p> |
