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J. Gao et al.
31.1 Introduction
With the rapid development of the petroleum industry, the reserves of crude oil and
refined oil are crucial. In the oil reserve system, the tank is the core equipment, and the
corrosion of the tank floor is the main factor affecting its safe operation. At present, the
detection method of the storage tank is mainly combined with the on-line detection of
acoustic emission and the magnetic leakage scanning detection, and is supplemented
by other conventional non-destructive testing methods [1–3]. Although the acoustic
emission on-line detection can realize the hierarchical quantitative evaluation of the
corrosion state of the tank bottom plate, when the large-scale storage tank (volume is
above 20,000 m
3 ) is in-line detection, the acoustic emission signal generated in the
middle area of the bottom plate is affected by attenuation and other factors. It cannot
be received by sensors coupled to the outer wall of the tank, forming the blind zone
for detection. The detection blind zone increases with the increase of the diameter of
the tank bottom plate. Therefore, when acoustic emission online detection is adopted
for large storage tanks, due to the blind area of detection, it is impossible to evaluate
the corrosion defect activity of the whole bottom plate of storage tanks, resulting
in inaccurate evaluation results, affecting the final tank inspection and maintenance
decision, and bringing safety risks.
Immersion acoustic detection method can solve the above problems [4]. By
placing an automatic detector equipped with acoustic sensors from the manhole
above the tank and controlling the detector to walk along the preset route to complete
the area detection of the tank bottom plate, the global detection of the tank bottom
plate can be realized. In this method, the location of corrosion sound source is the
key. In this paper, the acoustic positioning method of planar small array unit is established, and the validity of the method is verified by experimental simulation. Finally,
according to the immersion detection method, a prototype of tank bottom plate global
detector is designed.
31.2 Large-Scale Tank Floor Immersion Acoustic Global
Detection Method
31.2.1 Problems in Online Detection of Acoustic Emission
from Large Tank Bottom Plates
At present, the most effective detection method for tank bottom plate corrosion is
acoustic emission online detection technology. The method utilizes a plurality of
acoustic emission sensors equally coupled to the outer wall of the tank and receives
corrosion acoustic signals from the tank floor. Then, the position of the sound source
is located by the corrosion acoustic emission signal received by sensors, and the
corrosion state of the sound source is evaluated according to the detection standard.
J. Gao et al.
31.1 Introduction
With the rapid development of the petroleum industry, the reserves of crude oil and
refined oil are crucial. In the oil reserve system, the tank is the core equipment, and the
corrosion of the tank floor is the main factor affecting its safe operation. At present, the
detection method of the storage tank is mainly combined with the on-line detection of
acoustic emission and the magnetic leakage scanning detection, and is supplemented
by other conventional non-destructive testing methods [1–3]. Although the acoustic
emission on-line detection can realize the hierarchical quantitative evaluation of the
corrosion state of the tank bottom plate, when the large-scale storage tank (volume is
above 20,000 m
3 ) is in-line detection, the acoustic emission signal generated in the
middle area of the bottom plate is affected by attenuation and other factors. It cannot
be received by sensors coupled to the outer wall of the tank, forming the blind zone
for detection. The detection blind zone increases with the increase of the diameter of
the tank bottom plate. Therefore, when acoustic emission online detection is adopted
for large storage tanks, due to the blind area of detection, it is impossible to evaluate
the corrosion defect activity of the whole bottom plate of storage tanks, resulting
in inaccurate evaluation results, affecting the final tank inspection and maintenance
decision, and bringing safety risks.
Immersion acoustic detection method can solve the above problems [4]. By
placing an automatic detector equipped with acoustic sensors from the manhole
above the tank and controlling the detector to walk along the preset route to complete
the area detection of the tank bottom plate, the global detection of the tank bottom
plate can be realized. In this method, the location of corrosion sound source is the
key. In this paper, the acoustic positioning method of planar small array unit is established, and the validity of the method is verified by experimental simulation. Finally,
according to the immersion detection method, a prototype of tank bottom plate global
detector is designed.
31.2 Large-Scale Tank Floor Immersion Acoustic Global
Detection Method
31.2.1 Problems in Online Detection of Acoustic Emission
from Large Tank Bottom Plates
At present, the most effective detection method for tank bottom plate corrosion is
acoustic emission online detection technology. The method utilizes a plurality of
acoustic emission sensors equally coupled to the outer wall of the tank and receives
corrosion acoustic signals from the tank floor. Then, the position of the sound source
is located by the corrosion acoustic emission signal received by sensors, and the
corrosion state of the sound source is evaluated according to the detection standard.