Device and method for measuring average particle size of pulverized coal

The invention discloses a device and a method for measuring the average particle size of pulverized coal. The device is used for off-line measurement to obtain a particle calibration function or used for on-line measurement of the average particle size of pulverized coal. The method comprises the steps that 1, a particle size calibration function f (D) is measured off line, t = f (D) is obtained through fitting, and f (D) is a function about the average particle size D; 2, the average particle size of the pulverized coal is measured online, in the online measurement process, the mass concentration W, the incident light intensity I0 and the emergent light intensity I of the pulverized coal are recorded in real time, t is obtained through fitting (0, 0) and coordinates of the two points through an exponential function y = 1-exp (-x/t), x represents the mass concentration of the particles, y represents the normalized light intensity difference, t is substituted into a function t = f (D), and the average particle