US 5,320,967 AGranted

Boiler system leak detection

AssigneeNalco Chemical Company

InventorsStanley C. Avallone, Roger W. Fowee, James R. MacDonald, Nicholas J. Furibondo

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Abstract

Leakage of water from a boiler water system wherein steam is generated in a boiler from feedwater fed to the boiler, and the concentration of impurities in the boiler water within the boiler is reduced by withdrawing fractions thereof as blowdown while admitting additional feedwater as boiler-water makeup, is determined. The boiler has a concentration cycle value, the concentration cycle value being the average value of the concentration of an inert component in the blowdown at steady state (C.sub.F) divided by the concentration of the inert component in the feedwater (C.sub.I). The concentration of the inert component in the boiler at steady state varies from a high concentration C.sub.H, having a value that is higher than C.sub.F, to a low concentration C.sub.L, having a value between the (C.sub.I) and the (C.sub.F), within a time period. The method comprises: employing as the inert component an inert tracer; sensing a characteristic of the inert tracer in the boiler at steady state equivalent to its concentration in the boiler water; converting the sensed characteristic to a value equivalent to the concentration of the inert tracer in the boiler water; and activation of a signal when a variance in the cyclic concentration fluctuation of said inert tracer occurs that is consistent with a leakage of boiler water.

Claims22

Dependent claims

A method of determining leakage from a boiler water system wherein steam is generated in a boiler from feedwater fed to said boiler, said feedwater introducing impurities to boiler water within said boiler and the concentration of said impurities in said boiler water within said boiler is reduced by withdrawing fractions of said boiler water from said boiler as normal blowdown by means of a blowdown valve operation while admitting additional feedwater to said boiler as boiler-water makeup, said boiler having a concentration cycle value, said concentration cycle value being the average value of the concentration of an inert component in said boiler water at steady state C.sub.F divided by the concentration of said inert component in said feedwater C.sub.I, said concentration of said inert component in said boiler at steady state varying from a normal high concentration C.sub.H, said normal high concentration C.sub.H having a value higher than said C.sub.F, to a normal low concentration C.sub.L, said normal low concentration C.sub.L having a value between said C.sub.I and said C.sub.F, within a time period, comprising:

employing as said inert component an inert tracer added to said boiler water at a rate equivalent to a known concentration C.sub.I of said inert tracer with respect to said feedwater;
sensing a characteristic of said inert tracer in said normal blowdown at steady state correlated to its concentration in said boiler water on a substantially continuous basis and thereby obtaining a plurality of sensed characteristic values;
converting said plurality of sensed characteristic values to a plurality of values each equivalent to said concentration of said inert tracer in said boiler water;
optionally recording said cyclic concentration fluctuation of said inert tracer from C.sub.H to C.sub.L in said boiler water;
and
activation of a signal upon the detection of a variance indicator that indicates a variance in said cyclic concentration fluctuation consistent with a leakage of a fraction of said boiler water from said boiler in combination with a posture of said blowdown valve.

3 more elements

A method of determining leakage from a boiler water system wherein steam is generated in a boiler from feedwater fed to said boiler, said feedwater introducing impurities to boiler water within said boiler and the concentration of said impurities in said boiler water within said boiler is reduced by withdrawing fractions of said boiler water from said boiler as normal blowdown while admitting additional feedwater as boiler-water makeup, said boiler having a concentration cycle value, said concentration cycle value being the average concentration of an inert component in said boiler water at steady state C.sub.F divided by the concentration of said inert component in said feedwater C.sub.I, said concentration of said inert component in said boiler water at steady state varying in a cyclic concentration fluctuation from a normal high concentration C.sub.H, said normal high concentration C.sub.H having a value higher than said C.sub.F, to a normal low concentration C.sub.L, said normal low concentration C.sub.l having a value between said C.sub.I and C.sub.F, within a time period, comprising:

employing as said inert component an inert tracer to said boiler water at a rate equivalent to a known concentration C.sub.I of said inert tracer with respect to said feedwater;
sensing a characteristic of said inert tracer in said normal blowdown at steady state correlated to its concentration in said boiler water on a substantially continuous basis and thereby obtaining a plurality of sensed characteristic values;
converting said plurality of sensed characteristic values to a plurality of values each equivalent to said concentration of said inert tracer in said boiler water and therefrom determining said cyclic concentration fluctuation of said inert tracer;
optionally recording said cyclic concentration fluctuation of said inert tracer;
wherein a variance indicator is an inert tracer concentration in said boiler water less than said normal low C.sub.L concentration of said inert tracer or an inert tracer concentration in said boiler water that fails to reach said normal high C.sub.H concentration within a time period B, said time period B being at least about that of the time period in which said fluctuation of said inert tracer between said normal high concentration C.sub.H and said normal low concentration C.sub.L normally occurs, and
comparing said variance indicator to an operating parameter of said boiler system and activating a signal when said variance indicator is detected at the same time than an imbalance in said operating parameter is seen.

3 more elements

A method of determining leakage from a boiler water system wherein steam is generated in a boiler from feedwater fed to said boiler, said feedwater introducing impurities to boiler water within said boiler and the concentration of said impurities in said boiler water within said boiler is reduced by withdrawing fractions of said boiler water from said boiler as normal blowdown while admitting additional feedwater as boiler-water makeup, said boiler having a concentration cycle value, said concentration cycle value being the average concentration of an inert component in said boiler water at steady state C.sub.F divided by the concentration of said inert component in said feedwater C.sub.I, said concentration of said inert component in said boiler at steady state varying in a cyclic concentration from a normal high concentration C.sub.H, said normal high concentration C.sub.F having a value that is higher than C.sub.F, to a normal low concentration C.sub.L, said normal low concentration C.sub.L having a value between said C.sub.I and said C.sub.F, within a time period, comprising:

employing as said inert component an inert tracer added to said boiler water at a rate equivalent to a known concentration C.sub.I of said inert tracer with respect to said feedwater;
sensing a characteristic of said inert tracer in said normal blowdown at steady state correlated to its concentration in said boiler water on a substantially continuous basis and thereby obtaining a plurality of sensed characteristic values;
converting said plurality of sensed characteristic values to a plurality of values each equivalent to said concentration of said inert tracer in said boiler water and therefrom determining said cyclic concentration fluctuation of said inert tracer from said normal high concentration C.sub.H to said normal low concentration C.sub.L in said boiler water;
optionally recording said cyclic concentration fluctuation of said inert tracer from said normal high concentration C.sub.H to said normal low concentration C.sub.L in said boiler water;
and
activation of a signal upon the detection of a variance indicator that indicates a variance in said cyclic concentration fluctuation of said inert tracer consistent with a leakage of a fraction of said boiler water from said boiler.

3 more elements

Dependencies are inferred from the claim text.