Recovery boiler leak detection system and method

A method for detecting a leak in a boiler system of the type having a boiler drum wherein a drum balance is determinable, said method comprising the steps of:

• (a) calculating a pair of short and long term averages, said short term average based on a certain number of drum balance data, and said long term average based on a certain number of drum balance data, wherein the number of drum balance data of said short term average is less than the number of drum balance data of said long term average;
• (b) calculating a difference between each pair in step (a);
• (c) determining if a difference in step (b) is significant according to its t.sub.test ;
• (d) reiterating steps (a), (b), and (c) at least once wherein each reiterated pair of short and long term averages includes at least one drum balance datum that is more recent than any datum on which a previously calculated short and long term average is based;
• and
• (e) monitoring a pattern of significant differences calculated in step (c) and indicating a leak if said pattern exceeds a predetermined limit, wherein said predetermined limit is selected from the group consisting of two or more significant differences within a certain period and two or more consecutive significant differences.

An apparatus for detecting a leak in a boiler system of the type having a boiler drum wherein a drum balance is determinable, said apparatus comprising:

• (a) means for calculating at least a first pair of short and long term averages and a second pair of short and long term averages;
• said short and long term averages of said first pair being based on a certain number of drum balance data, N.sub.1 and N.sub.2, respectively, wherein N.sub.1 is less than N.sub.2 ;
• said short and long term averages of said second pair based on a certain number of drum balance data, N.sub.1 ' and N.sub.2 ' respectively, wherein N.sub.1 ' is less than N.sub.2 ';
• and wherein N.sub.2 is less than N.sub.2 ';
• (b) means for calculating a difference between each pair of step (a);
• (c) means for determining if a difference calculated in step (b) is significant according to its t.sub.test ;
• and
• (d) means for indicating a leak if a difference is significant according to step (c), wherein an indication of a leak is associated with a confidence level, said confidence level being higher for a significant difference based on said second pair relative to a significant difference based on said first pair.

A system for detecting a leak in a boiler system of the type having a boiler drum wherein a drum balance is determinable, said system comprising a computer program for performing the steps of:

• (a) calculating at least a first pair of short and long term averages and a second pair of short and long term averages;
• said short and long term averages of said first pair being based on a certain number of drum balance data, N.sub.1 and N.sub.2, respectively, wherein N.sub.1 is less than N.sub.2 ;
• said short and long term averages of said second pair based on a certain number of drum balance data, N.sub.1 ' and N.sub.2 ' respectively, wherein N.sub.1 ' is less than N.sub.2 ';
• and wherein N.sub.2 is less than N.sub.2 ';
• (b) calculating a difference between each pair of step (a);
• (c) determining if a difference calculated in step (b) is significant according to its t.sub.test ;
• and
• (d) indicating a leak if a difference is significant according to step (c), wherein an indication of a leak is associated with a confidence level, said confidence level being higher for a significant difference based on said second pair relative to a significant difference based on said first pair.