Patent ID: 7249470

Claim:
A method of controlling the production of at least one liquid product produced by at least one plant over a forecast time interval, the at least one plant having a liquid storage capacity and consuming electrical power to produce the at least one liquid product, said method comprising: continually, upon the elapse of a calculation time interval equal to the forecast time interval: calculating a rate of change of liquid inventory of the at least one liquid product contained with the liquid storage capacity over a past time interval equal to the calculation time interval and ending upon the calculation of the rate of change of liquid inventory; inputting input linguistic values referable to current liquid inventory, the rate of change of liquid inventory, a current production rate of the at least one liquid product by the at least one plant, projected demand requirements for the at least one liquid product and projected unit power costs for the electrical power over the forecast time interval into an expert system controller employing fuzzy logic to apply the input linguistic values to at least one rule set to obtain output linguistic values and to convert the output linguistic values into an output numerical value of a forecasted differential production rate for the at least one liquid product; the at least one rule set and the input linguistic values defined such that the forecasted differential production rate tends to decrease as the rate of change and/or the liquid inventory and/or the projected unit power costs increase and the differential production rate tends to increase as the projected demand requirements increase and vice-versa; adding the output numerical value of the forecasted differential production rate to the current production rate to obtain a new production rate; and controlling the plant to produce the at least one liquid product at the new production rate during the forecast time interval.