Abstract: A system and method for presenting the tradeoffs among the sensitivity, false alarms and off-line operation of recovery boiler leak detection systems. For any given recovery boiler, the system and method utilizes prior data from that recovery boiler to provide the operator of that boiler with the ability to balance how sensitive the recovery boiler leak detection system can be along with how many false alarms of the recovery boiler leak detection system will be tolerated and along with how much off-line operation of the recovery boiler leak detection system will be acceptable.

Abstract: Methods and apparatus are provided for detection of leaks in boilers containing a temperature control liquid which is supplemented with feedwater and removed as blowdown, main steam and sootblower steam. In a preferred embodiment, the boiler has an automatic liquid level control mechanism. The methods include measuring rates associated with feedwater supplementation and removal, correcting for the offsets between the supplementation and removal rates, determining the unaccounted for water rate, and comparing the unaccounted for water rate with zero to determine if a leak condition is present.

Abstract: A method and system for detecting and estimating leaks in an industrial boiler whereby the method and system formulate the leak detection problem as a least squares fitting problem, where one or more of the fitted parameters estimate leak flows. The method and system create a representation that incorporates a leak model component, a process model component and a noise model component into the representation. This invention provides a variety of leak dotproduct.sub.ij (tCurrent)=exp(-(tCurrent-tPrevious)/Tau.sub.ij)* dotproduct.sub.ij (tPrevious)+(1-exp(-min(t/Current-tPrevious, maxDt)/ Tau.sub.ij))*x.sub.i (tCurrent)*x.sub.j (tCurrent).

Abstract: A control system for automatically achieving and maintaining a desired sodium/phosphate ratio and phosphate concentration of the boiler water in an industrial boiler for minimizing corrosion. The system uses an adaptive controller that models the boiler which enables the system to predict boiler pH and phosphate concentrations at any future time given the feed rates, feed concentrations of high and low sodium/phosphate stocks, blowdown rate, mass of the boiler water, initial boiler phosphate concentration and initial pH. Once these future concentrations are determined, the controller then determines which feed rates will return the current boiler water state to, and then maintain the boiler water at, the desired sodium/phosphate congruency ratio in the least amount of time.

Abstract: A method for stabilizing an aqueous solution containing sulfite or bisulfite ions and a water-soluble metal catalyst. The method comprises incorporating a stabilizing amount of a alpha substituted carboxylic acid or salt thereof or a vinyl carboxylic acid or salt thereof in the solution. The carboxylic acid inhibits sludge formation when the aqueous solution is stored. The preferred carboxylic acid, citric acid, also enhances the oxygen scavenging rate of the sulfite and bisulfite when the solution is used to treat aqueous systems for oxygen removal.

Abstract: Methods and apparatus are provided for using tracers to monitor industrial process equipment to which liquid is added and from which liquid is removed. In preferred embodiments, the methods are directed to detecting water leakage in a boiler in which an aqueous temperature control liquid is supplemented with feedwater at a known or unknown rate and is removed as blowdown, sootblower steam and steam at a known rate.

Abstract: Methods and apparatus are provided for using tracers to monitor industrial process equipment to which liquid is added and from which liquid is removed. In preferred embodiments, the methods are directed to detecting water leakage in a boiler in which an aqueous temperature control liquid is supplemented with feedwater at a known or unknown rate and is removed as blowdown at a known rate. The methods include determining the blowdown removal rate, adding a tracer to the temperature control liquid at a rate that is directly proportional to the blowdown removal rate, analyzing the blowdown to determine the measured concentration of tracer contained therein, deriving an expected concentration of tracer in the blowdown, and comparing the measured and expected concentrations to detect excessive variance between them.

Abstract: An improved oxygen scavenger for aqueous mediums is disclosed which is a disubstituted, water soluble azo compound.

Abstract: An improved oxygen scavenger for aqueous mediums is disclosed which is a hydroxyalkylhydroxylamine. The material may be catalyzed with a compound such as copper, hydroquinone, benzoquinone, 1,2-naphthoquinone-4-sulfonic acid, pyrogallol and t-butylcatechol. Hydroxyalkyl substituted hydroxyalmines of the general formula HO-N-[CH.sub.2 --CH(OH)--R].sub.2 wherein R is H or C.sub.1 to C.sub.10 alkyl have been found to be effective oxygen scavengers for aqueous systems such as industrial water system.

Abstract: Methods are provided for simultaneously inhibiting the corrosion of iron-containing and copper-containing metals in contact with boiler feedwaters. The methods comprise adding an effective amount of 1,10-phenanthroline to the boiler feedwater system for which corrosion inhibition is desired.