Case Studies

TRACERCO Diagnostics™ Leak Study

Ammonia Converter Passing Bypass Valve

Temperature measurements and chemical analysis of the gas at the exit of an ammonia converter showed that abnormalities were occurring. These could have been formed from:-

a) poor catalytic conversion
b) a leaking bellows within the converter
c) leakage through a supposedly isolated bypass valve.

A sharp pulse of gaseous radiotracer was injected into the interchanger bypass line. Four detectors were placed and were used to check for a leak in the bottom bellows and to measure (i) the gas velocity at the exit of the converter and (ii) the gas velocity after the junction with the converter bypass valve line. The measured gas velocities were 37 feet/second and 57 feet/second for the sections of line between D2/D3 and D3/D4 respectively. From these measurements and knowledge of the internal pipe diameters the volume flowrates were calculated. These calculations showed that 35% of the total gas flowrate to the product cooler was leaking through the converter bypass valve. The tests showed that the bottom bellows were also leaking.

Because the measurements showed that there were two causes of malfunction and because of the precise diagnosis of the two faults, maintenance effort was concentrated on the problem area and the shutdown time was minimized.

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