Abstract: A calculation device is configured to calculate a value relating to a combustible target gas containing miscellaneous gas components. The calculation device includes: a heating value calculation unit configured to calculate a heating value of the target gas on the basis of converted heating values obtained from a refractive index and a density of the target gas, respectively; a miscellaneous gas total approximate-concentration calculation unit configured to calculate an approximate concentration of the miscellaneous gas components on the basis of the converted heating values; and a virtual basic-heating-value calculation unit configured to calculate, on the basis of the heating value and the approximate concentration, a virtual basic heating value of the target gas when the miscellaneous gas components are assumed to be removed.

Abstract: A composition analysis apparatus for analyzing a composition of a gas includes: a first measurement part measuring concentrations of gases included in a gas to be analyzed; a part calculating converted calorific values, the part including a second measurement part measuring a refractive index of the gas and a speed of a sound propagating through the gas and calculating a converted calorific value of the gas for the refractive index and the sound speed; a part calculating a base miscellaneous gas total error calorific value, the part calculating, based on the converted calorific values, a base error calorific value of an error calorific value attributable to miscellaneous gases included in the gas; and a part calculating a concentration of a first gas not to be measured, the part calculating the concentration of the first gas based on the concentrations of the measured gases and the base error calorific value.

Abstract: A composition analysis apparatus for analyzing a composition of a gas includes: a first measurement part measuring concentrations of gases included in a gas to be analyzed; a part calculating converted calorific values, the part including a second measurement part measuring a refractive index of the gas and a speed of a sound propagating through the gas and calculating a converted calorific value of the gas for the refractive index and the sound speed; a part calculating a base miscellaneous gas total error calorific value, the part calculating, based on the converted calorific values, a base error calorific value of an error calorific value attributable to miscellaneous gases included in the gas; and a part calculating a concentration of a first gas not to be measured, the part calculating the concentration of the first gas based on the concentrations of the measured gases and the base error calorific value.

Abstract: It is an object of the present invention to provide a calorific value measuring device and a calorific value measuring method which enable highly reliable measurement of the calorific value of a by-product gas produced in a steelmaking process. In the present invention, with a by-product gas produced in a steelmaking process being employed as an object gas of which calorific value is to be measured, the refractive index and the sonic speed of the by-product gas are measured so as to compute a refractive index equivalent calorific value QO from the value of the refractive index as well as a sonic speed equivalent calorific value QS from the value of the sonic speed. On the basis of the concentration XCO of carbon monoxide gas contained in the by-product gas, an error calorific value QCO is computed by Equation (1) below using a value selected within a range of ?0.08 to ?0.03 as a calorific value equivalent coefficient ?.

Abstract: The present invention has as its object the provision of a methane number calculation method that allows for readily acquiring a methane number of a natural gas, which is a sample gas to be measured, with acceptable reliability irrespective of toe gas composition, and as another object the provision of a methane number measurement device that is capable of monitoring the fuel property of a natural gas to be used as a fuel gas.

Abstract: It is an object of the present invention to provide a calorific value measuring device and a calorific value measuring method which enable highly reliable measurement of the calorific value of a by-product gas produced in a steelmaking process. In the present invention, with a by-product gas produced in a steelmaking process being employed as an object gas of which calorific value is to be measured, the refractive index and the sonic speed of the by-product gas are measured so as to compute a refractive index equivalent calorific value QO from the value of the refractive index as well as a sonic speed equivalent calorific value QS from the value of the sonic speed. On the basis of the concentration XCO of carbon monoxide gas contained in the by-product gas, an error calorific value QCO is computed by Equation (1) below using a value selected within a range of ?0.08 to ?0.03 as a calorific value equivalent coefficient ?.

Abstract: The present invention has as its object the provision of a methane number calculation method that allows for readily acquiring a methane number of a natural gas, which is a sample gas to be measured, with acceptable reliability irrespective of toe gas composition, and as another object the provision of a methane number measurement device that is capable of monitoring the fuel property of a natural gas to be used as a fuel gas.

Abstract: A method for measuring specific gravity of a combustible gas includes measuring the refractive index and sound speed of a gas of interest which contains at least one type of gas selected from a hydrocarbon gas, hydrogen gas, and carbon monoxide gas, and computing the value of the specific gravity Da of the gas of interest from Equation (1) below using a value selected as a correction factor x from within a range of 2.4 to 9.3 on the basis of a refractive index converted specific gravity Dn determined from the refractive index and a sound speed converted specific gravity Ds determined from the sound speed: Da=Ds?[(Ds?Dn)/(1?x)]??Equation (1).

Abstract: A frame is formed by forming in a base having at least three through-holes 2, 3 and 4 in the same cross section cavities 6 and 7 crossing said through-holes 2 to 5 at a given distance. A cell is formed by sealing an area sandwiched by said two cavities 6 and 7 with translucent sheets 8 and 9. Interference fringes are generated by sending two beams from a light-source element 19 into the cell through as parallel plane mirror 14 and reflecting the beams from the cell to a single spot on the parallel plane mirror 14 through a prism 15.