Research And Design For Intelligent Energy Metering Instrument Of Natural Gas

Natural gas is a kind of multi-component mixed gaseous fuel. It has the advantages of safety, high calorific value and cleaning while compared with the traditional energy sources such as coal and oil. At present, the measurement method is volume measurement in China, but the value in use of natural gas lies in its energy. And, the energy of natural gas is closely related to its components. The energy of natural gas is variable in different area and different time because its energy is relation to its components. So the energy measurement is the trend of natural gas metrology. In order to solve the problem, an instrument of energy measurement for natural gas is put forward in this thesis. The main work are as follows:Firstly, analysis and comparison about natural gas measurement between China. and foreign country is carried out, and a kind of indirect measurement of scheme is Put forward. The standard flow is calculated by turbine flow sensor, pressure sensor and temperature sensor in this scheme. Calorific value of natural gas can be acquired by 485 communication interface, and the energy of natural gas can be figure out in the next. Secondly, the design of instrument structure with branch pipeline has been done. Several important parameters of the branch pipeline are simulated by FLUENT, the relationship between spilt ratio and the flow and mechanical structure are researched. Thirdly, the hardware circuit and software of energy integrating instrument are designed. The design of hardware circuit includes flow signal acquisition, temperature signal acquisition, pressure signal acquisition, LCD display, key interface and communication;The design of software includes flow measurement, temperature measurement, pressure measurement, energy measurement communication and key process.At the end of this thesis, the experimental study of the prototype is conducted. The temperature, pressure and flow experiment are done with their corresponding standard equipments. The error of temperature measurement is less than 0.2?. The temperature compensation is obtained and the pressure measurement error is less than 0.5%. The standard volume error is less than 0.7%. The energy measurement uncertainty is analyzed on the basic of the experimental data.