Article is devoted to the issue of selecting a gas representative sample directly of consumer (from low-pressure gas pipelines) as well as conducting representative studies of the natural gas heat combustion by using a direct method with gas calorimeter. Article describes the disadvantages of chromatographic method for determining the heat of gas combustion and indicates the necessity of developing a gas calorimeter. Development of a sampler on the basis of a typical cylinder with the using pneumatic drive of various configurations is proposed. Lack of existing samplers is proved. Consideration is related to the displacement of the gas sample taken with help of excessive air pressure. The latter can significantly change the value of the heat of gas combustion.
We have developed a complex of technical means, which consists of a cylinder - dispenser with a pneumatic drive of a "tandem" type cylinder and a gas meter. Applying the "tandem" cylinder as a pneumatic actuator provides additional benefits that are associated with an increase in the overall effort on the drive rod. Developed complex links the piping system of gas pipelines and the calorimetric column, in which the sampling gas is burned directly and the combustion heat is sequentially determined. Mentioned cylinder - dispenser can be used in the mode of the piston sampler, and in the setting mode - dispenser, the metering device of the volumetric flow rate of natural gas. To select the gas sample, a method of using the cylinder - the dispenser is developed. While determination of the gas amount is performed, application of the pulse interpolation procedure aiming accuracy enhancement is proposed. For representative research, the heat of natural gas combustion is measured by direct measurement: application of calorimeter with the direct burning of natural gas and the complex of technical means for carrying out selection, injection, transportation, etc.
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