New Patents VII

a far smaller dewatering load than in the typical conventional methods using an inorganic salt and a pH adjusting reagent.

5006786

DEVICE FOR IN SITU MONITORING OF CORROSION

RATES OF POLARIZED OR UNPOLARIZED METALS

Michael C H McKubre, Barry C Syrett assigned to Electric Power Research Institute Inc

reduction in its surface voltage which reduction is proportional to the dose of gamma and/or X- ray incidence on the chamber. The reduction of the electret surface voltage is used to calculate the dose of gamma or X-ray radiation incident upon the chamber during a known exposure period. In the preferred embodiment, filtered holes in the chamber permit radon to diffuse out of the ion chamber. A sealed outer container containing an absorbent such as activated char- coal surrounds the inner ion chamber to remove any radon captured within the container and to prevent any ambient radon from entering the ion chamber. Removal of this radon removes its un- desirable contribution to the gamma/X-ray dose signal and thereby enhances the accuracy of the monitor.

A technique for electrochemical measurement of the corrosion current (corrosion rate) deter- mines the electrochemical parameters that are necessary to calculate the corrosion rate as they are contained in the harmonic current response to a moderate amplitude sinusoidal voltage per- turbation applied to the corroding metallic com- ponent. The harmonic current response is analyzed at frequencies If, 2f, 3f, 4f, 5f and the rectification current response of DC current to the presence of a 20-50 mV AC voltage perturba- tion at a frequency f. The free corrosion current density, the free corrosion potential and the Tafel coefficients are calculated. The Tafel coef- ficient or Tafel slope is a measure of the exponen- tial dependence at the rate of corrosion in a material. From these data, the dissolution cur- rent is calculated, which in turn is integrated with respect to time to yield a cumulative mass loss.

5008540

ELECTRET GAMMA/X-RAY LOW LEVEL DOSIMETER

John Dempsey assigned to Rad Elec Inc

A small enclosed ion chamber with an elec- trostatically charged electret attached to the in- ner chamber wall. Positive or negative ions (depending on the polarity of the electret charge) formed in the chamber air by the passing of gamma radiation or X-rays move to and collect on the electret surface by virtue of its elec- trostatic attraction to ions of opposite polarity. These ions neutralize the ions of opposite polarity on the electret and cause a measurable

5012750

APPARATUS FOR RECOVERY OF CONSTITUENTS AND HEAT

FROM FLUIDIZED BED COMBUSTION

Harold Sheely, Constantine D Miserlis, Ivan L Rosenblatt assigned to International Paper Company

An apparatus and method for recovering con- stituents and/or heat energy from a fluidized bed combustion process utilizes a single vessel which combines a combustor for fluidized bed combus- tion of a chemical mixture fed therein and a heat exchange section. Characteristics of the fluidized bed are controlled by withdrawing an ap- propriate portion of the larger, unburned con- stituent particles from the bottom of the combustor, and smaller constituent particles are withdrawn by becoming entrained within the gases of combustion and being transported to the heat exchange section. The smaller particles are separated from the gases without the use of a cyclone separator and accumulate as another fluidized bed in the heat exchange section where heat is adsorbed from the particles for recovery purposes and to cool the particles. A portion of the cooled particles is then recirculated to the combustor by, for example, pneumatic transport methods for controlling the operating tempera- ture of the combustion process. The apparatus is particularly well-suited for recovering process salts and heat energy from the burning of black liquor effluent from a lignocellulosic pulping process.