Control system for industrial water system and method for its use

A control system for monitoring and controlling a health of a heat transfer surface of a heat exchanger in an industrial water system, comprising:

• a testing heat exchanger comprising a test surface, wherein the testing heat exchanger is configured to detect scaling or fouling first in the control system;
• a temperature sensor configured to measure a maximum temperature T1 the test surface can reach without triggering scaling or fouling of the test surface, the scaling or fouling being determined by an increase in heat resistance of the test surface;
• and
• a controller configured to compare the maximum temperature T1 of the test surface and a temperature T0 of the heat transfer surface, and to control at least one manipulated variable in response to the comparison between the maximum temperature T1 and the temperature T0,
• wherein the at least one manipulated variable comprises at least one selected from the group consisting of chemical feed rates, makeup water flow rate, blowdown water flow rate, and recirculating water flow rate, and
• wherein the controller is further configured to:
• receive data related to at least one measured disturbance, the at least one manipulated variable, and a temperature difference ΔT between the maximum temperature T1 and the temperature T0,
• utilize the data and predetermined dynamic correlations between the at least one measured disturbance and the temperature difference ΔT and between the at least one manipulated variable and the temperature difference ΔT to construct a performance index comprising a weighted summation associated with present and future predicted values of ΔT and a cost index comprising a weighted summation of present and future predicted costs associated with the at least one manipulated variable,
• adjust the at least one manipulated variable to simultaneously maximize the performance index and thereby reduce the present and future values of ΔT, and
• minimize the cost index and thereby reduce the present and future predicted costs,
• wherein the at least one measured disturbance comprises at least one selected from the group consisting of composition changes of source water, water losses from a recirculating system, changes in production rates, changes in environment, and changes in system structure.