[MW:21384] Boiler Unit#3 H2 Damage

JLEC is a 6 unit bituminous coal fired power complex (http://www.jlec.ma/fr/index.aspx), located in El Jadida, Morocco. Units 1 and 2 are once-through tower boilers manufactured by GEC Alstom – Stein Industry. They are corner-fired with spiral-wound wall tubes in the lower furnace section, and vertical wall tubes in the upper furnace section of the boiler. The upper furnace area contains the Economizer, Superheater, and Reheater assemblies of the boiler. Units 3 and 4 are assisted-circulation boilers manufactured by CE - ABB. They are corner-fired with straight water walls tubes in furnace of the boiler. The upper furnace and convective areas contain the Superheater, and Reheater sections (elements). The back pass section contains Low Temperature Superheater and Economizer. Unit 1 and 2 were placed in service in 1994 and unit 3 and 4 in 2000.

Operting condition ( Design):

Boiler tube failure

Boiler Unit#3 was put out of service 2 times due to H2 damage tubes leak in the lower sloped furnace tubing in 31 May and 21 June 2014 juste after minor outage start up off 29 May 2014. Condenser sea water leakage happened during the shutdown due to the damage off the condenser tubes after the fouling off LP by pass strainer.

Unit was out off service from 21 June to 6 July 2014 in order to replace the damage tube and to perform the NDE to identify the area impacted by H2 damage. Special cooled and hot blowdown were performed to eliminate the maximun of oxide iron.

Objective:

Our Company intends to conduct boiler audits in order to answer to this question: what we should do to avoid this failure. All needed finding (forced outage report, metallurgical analysis, data collection from the control room software are available for analysis.

In the some time, we need some feed back about lower drums offirices plates replacement ( replacement according to visual inspection or juste preventive replacement).

Best regards,
Mostafa

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