Abstract: According to the leakage failure of the head of waste heat boiler at the outlet of high temperature transformer of the synthetic ammonia plant, this paper analyzes the equipment from such aspects as the structure, function and the blade seal technical transformation due to the insufficient heat exchange efficiency when the equipment being put into use at the beginning. The measures of online fastening and temporary bolt replacement were taken respectively. And it was found that the poor flatness of the sealing surface of the head flange was the main cause of equipment leakage during the shutdown and maintenance of the equipment. By machining and repairing the sealing surface of the head flange, the flatness accuracy requirements of the sealing surface were restored. And corresponding measures were taken to dismantle the tube bundle smoothly and replace the leaf seal, which ultimately eliminated the problem of head leakage and ensured the safe and stable operation of the equipment.

Key words: synthetic ammonia, waste heat boiler, head leakage, leaf seal, treatment