Research On Measurement Of The Moisture Contents In The Crude Oil By Microwave Transmission

The crude oil has been consumed increasingly with rapid development of modern industry, and moisture content in crude oil is a decisive reference parameter in crude oil mining and the refinement processing process, therefore accurate measurement of moisture content in crude oil has very important practical application value and significance.This article has studied various kinds of crude oil moisture content measuring techniques, by compared with each other, the non-contact microwave transmission method is selected finally, and a kind of new crude oil moisture content measurement system is designed, which is based on the microwave transmission method principle. This system consists of the measurement channel and the reference channel,whose main parts include microwave supply oscillator, the circulator, PIN modulation the switch, the numerical control attenuator, the precise adjustable attenuator, low noise power amplifier, wave-guide detector, sensor and so on. In the design process of the hardware system, HFSS is used to design a small caliber funnel-shaped antenna whose parameters such as directivity,gain and so on all meet the requirements of the system. With the design of the small caliber funnel-shaped antenna sensor, the experiment can be carried on in the small diameter vessel, and edge effect of antenna has been suppressed, also the measuring range is enhanced. Meanwhile the ADS simulation software has been used to simulate and give one method to design the microwave band low noise power amplifier.Because of reference channel, this system can overcome the influence on measurement precision which is caused by stability of the supply oscillator peak-to-peak value and the spatial. Numerical control attenuator is used in the reference channel, automatic calibration of the system is achieved through adjusting digit attenuator which is controlled by MCU. The measuring signal enters survey channel and the reference channel at different time that not only increases accurate of the measure, but also reduces the requests to the signal source power. Finally under the laboratory condition, the mixture of oil and water is used to simulate crude oil and experiment on oil and water mixture moisture content is carried on by designed microwave transmission measurement system. The experiment result has indicated that when moisture content is 10%-60%, this system has the high measuring accuracy. This system has the good instruction and significance on other aspects of microwave transmission method.