Deposit monitor

A fluid flow system for directing a fluid toward a use device comprising:

• a plurality of resistance temperature detectors (RTDs), the plurality of RTDs including a first RTD and a second RTD;
• a heating circuit in electrical communication with the plurality of RTDs and capable of applying electrical power to the RTDs;
• a measurement circuit in communication with the plurality of RTDs;
• a controller in communication with the heating circuit and the measurement circuit and capable of operating each of the plurality of RTDs in a heating mode via the heating circuit and a measurement mode via the measurement circuit, the controller being configured to:
• operate one or more of the plurality of RTDs in the heating mode of operation in order to maintain each of the one or more RTDs at a characterization temperature to induce a deposit from the process fluid to form on at least one of the one or more RTDs, at least one of the characterization temperatures being higher than a typical operating temperature of the use device, the operating the one or more of the plurality of RTDs in the heating mode of operation comprising maintaining the first RTD at a first characterization temperature and maintaining the second RTD at a second characterization temperature different from the first characterization temperature;
• for each of the one or more RTDs,
• periodically switch the RTD between the heating mode and the measurement mode in order to measure the temperature of the RTD,
• observe changes in the thermal behavior of the RTD in one or both of the heating mode and the measurement mode, and
• characterize a level of deposit from the process fluid onto the RTD based on the observed changes;
• determine a temperature-dependent deposition profile based on the characterized level of deposit of each of the one or more RTDs;
• and
• determine if a deposit condition exists for the use device based on the deposition profile.

A deposit analysis system comprising:

• a plurality of resistance temperature detectors (RTDs) positioned in a fluid flow system such that a surface of each of the plurality of RTDs is in thermal communication with the fluid flowing through the fluid flow system;
• a heating circuit in communication with each of the plurality of RTDs and being configured to apply a variable amount of electrical power to each of the RTDs in order to affect the temperature thereof;
• a measurement circuit in communication with each of the plurality of RTDs and being configured to output a signal representative of the temperature thereof;
• and
• a controller in communication with the heating circuit and the measurement circuit and configured to:
• for each of the plurality of RTDs:
• heat the RTD to a characterization temperature via the heating circuit, each of the plurality of RTDs being heated to a different characterization temperature;
• stop heating the RTD;
• characterize the temperature change of the RTD over time due to thermal conduction of heat from the RTD to the fluid flowing through the fluid flow system via the measurement circuit;
• and
• determine a level of deposit formed on the surface of the RTD from the fluid based on the characterized temperature change;
• and
• characterize a temperature dependence of deposition in the fluid flow system based on the determined level of deposit for each of the plurality of RTDs.