Apparatus for detecting corrosion rate of soil-covered storage tank after cathodic protection

An apparatus for detecting a corrosion rate of a soil-covered storage tank after cathodic protection, comprising:

• a tank body, a guard plate having a rectangular cuboid structure, bases symmetrically and fixedly connected to both bottom sides of the tank body, spherical heads fixedly connected to both ends of the tank body, a corrosion rate detection mechanism, and a computing chip, wherein guide rails are symmetrically and fixedly connected to an inner side of the guard plate, limit plates are fixedly connected to both ends of the guide rails, a threaded rod is rotatably connected between the two limit plates, guide rods are symmetrically arranged on an outer side of the threaded rod, a moving plate is threadedly connected to the outer side of the threaded rod, the threaded rod is fixedly connected to an output end of a motor, the motor is fixedly connected to an inner top wall of the guard plate, the corrosion rate detection mechanism is arranged on one side of the moving plate, the computing chip is electrically connected to the corrosion rate detection mechanism, and a corrosion rate computing module is arranged in the computing chip for computing the corrosion rate according to parameters collected by the corrosion rate detection mechanism and a preset mathematical model;
• the corrosion rate detection mechanism comprises a threaded sleeve having a cylindrical structure, a threaded seat is threadedly connected inside the threaded sleeve, an extension rod is rotatably connected to a central position inside the threaded seat, an arc-shaped plate is fixedly connected to one end of the extension rod and has an arc-shaped structure and an inner arc-shaped surface matching an outer surface of the tank body, an electrode sensor and a cleaning brush are fixedly connected to an inner side of the arc-shaped plate, and the electrode sensor is configured to detect a corrosion potential and current density on a surface of the tank body;
• a cathodic protector, configured to provide a cathodic protection current to the tank body, is fixedly connected to one side of the spherical heads and is electrically connected to an external power supply via a waterproof cable, a pipeline is fixedly connected to a lower end of one side of the spherical heads, and a gas concentration detector is fixedly connected to one end of the pipeline;
• and the corrosion rate computing module is configured to execute the following steps:
• S10:
• measuring electrochemical parameters on the surface of the tank body through the electrode sensor to obtain a potential value, a current density value, and a metal ion concentration value;
• S20:
• establishing an electrochemical model of corrosion, and computing a corrosion reaction rate constant according to the potential value, the current density value, and the metal ion concentration value;
• S30:
• acquiring environmental parameters, comprising soil resistivity, moisture content, pH, and redox potential;
• S40:
• establishing an environmental correction factor computing model according to the environmental parameters;
• S50:
• establishing a corrosion rate computing model, and combining the corrosion reaction rate constant with an environmental correction factor;
• S60:
• computing an instantaneous corrosion rate according to the corrosion rate computing model;
• S70:
• performing smoothing processing on the instantaneous corrosion rate using a moving time window method to obtain a steady-state corrosion rate;
• and
• S80:
• computing a corrosion depth according to the steady-state corrosion rate, and performing a corrosion warning judgment.