Systems and methods for measuring particle accumulation on reactor surfaces

A method for monitoring a particle/fluid mixture, comprising:

• flowing a mixture comprising charged particles and a fluid past a particle accumulation probe;
• measuring electrical signals detected by the probe as some charged particles pass the probe without contacting the probe while other charged particles contact the probe;
• manipulating the measured electrical signal to provide an output wherein manipulating the measured electrical signal includes using an absolute autocorrelation method that correlates mean centered data using an approaching curve indicating a charge on particles that approach the probe, a leaving curve indicating a charge on particles that pass and move away from the probe, and a zero-lag peak that indicates the charge on the particles that contact the probe to provide the output;
• and
• determining from the output if the charged particles contacting the probe have, on average, a different charge than the charged particles that pass the probe without contacting the probe.