Abstract: A method of controlling a pressure swing adsorption unit in which a manipulated variable such as a capacity factor used by such unit in setting the bed cycle time is updated with a manipulated variable computed within a controller. The controller has a feed forward level of control in which the updated manipulated variable is calculated from a probability function when the product is likely to go off spec as determined by the probability function. In such manner, an optimal manipulated variable can be calculated that will maximize recovery in a manner that the probability of the product going off spec will be acceptable. If a specific impurity within the product is above a targeted range, a change to the optimal manipulated variable is computed with the use of a feedback level of control utilizing fuzzy logic.

Abstract: Method for controlling the production of one or more liquid products produced by one or more plants, that can be an air separation plant, that has a liquid storage capacity and that consumes electrical power. Linguistic values related to current liquid inventory, a rate of change of liquid inventory, projected demand requirements and projected unit power costs are inputted into a expert system controller having one or more rule sets that apply such input linguistic values to produce output linguistic values that are converted back to an output numerical value of a forecasted differential production rate to be applied during a forecast period. The output numerical value of differential production is added to the current production rate of the plants to obtain a new production rate which is applied during the forecast period.

Abstract: Method for controlling the production of one or more liquid products produced by one or more plants, that can be an air separation plant, that has a liquid storage capacity and that consumes electrical power. Linguistic values related to current liquid inventory, a rate of change of liquid inventory, projected demand requirements and projected unit power costs are inputted into a expert system controller having one or more rule sets that apply such input linguistic values to produce output linguistic values that are converted back to an output numerical value of a forecasted differential production rate to be applied during a forecast period. The output numerical value of differential production is added to the current production rate of the plants to obtain a new production rate which is applied during the forecast period.