PARAMETRIC ANALYSIS OF THE PROPAGATION OF UNCERTAINTIES IN SORPTION MEASUREMENTS MADE WITH A PRESSURE-DECAY APPARATUS

The general formulation for the propagation of statistical uncertainti es is presented for the dual volume pressure decay method of measuring sorption capacity in polymers and other solid sorbents. These relatio nships are then used to determine the percent uncertainty in the calcu lated sorption coefficient (or capacity) with respect to ranges of val ues for several parameters that relate to choices in equipment design and operating conditions, and properties of the sorbent. These paramet ers include the ratio of system volumes, the relative volume of the so rbent, the accuracy and resolution of the sensors, the operating press ure, and the nominal sorption capacity of the sorbent. This analysis p rovides guidance for determining the uncertainty in the calculated sor ption capacity and minimizing that uncertainty within whatever logisti cal and resource constraints may exist.