Failure of reformer tube of an ammonia plant

Bhaumik, SK; Rangaraju, R; Parameswara, MA; Bhaskaran, TA; Venkataswamy, MA; Raghuram, AC; Krishnan, Radhesh

doi:10.1016/s1350-6307(01)00039-5

Cited by 30 publications

(17 citation statements)

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“…carburization and creep ductility exhaustion [2,[8][9][10]. This results in bulging, bending and ovalization of the tubes.…”

Section: Introductionmentioning

confidence: 99%

“…Pyrolysis tubes failure can be prevented by a combination of proper furnace operation, materials selection, regular inspections and appropriate design [2,[8][9][10][17][18][19]. Each pyrolysis plant performs with different and specific operating conditions and philosophies; hence each plant has characteristic causes for radiant coil failure [2].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of severe operation conditions on the degradation state of radiant coils in pyrolysis furnaces

Santos

Guedes

Baptista

et al. 2015

Engineering Failure Analysis

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“…carburization and creep ductility exhaustion [2,[8][9][10]. This results in bulging, bending and ovalization of the tubes.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of severe operation conditions on the degradation state of radiant coils in pyrolysis furnaces

Santos

Guedes

Baptista

et al. 2015

Engineering Failure Analysis

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“…A lot of trials and errors are involved when it is necessary to repair welds of these tubes. In some cases weld repair is impossible, or repair is not recommended [1][2][3][4][5] .…”

Section: Introductionmentioning

confidence: 99%

Microstructural analysis as the indicator for suitability of weld repairing of the heat resistant Cr - Ni steel

Odanović¹,

Blačić²,

Vračarić³

et al. 2010

REVMETAL

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Metallurgical evaluation was performed on a fractured column tube of the reformer furnace in an ammonia plant. The tubes were manufactured from centrifugally cast heat resistant steel HK 40. Optical and scanning electron microscope (SEM) were used for microstructural and fracture analysis. For composition determination of the microconstituents energy dispersive X ray spectroscopy (EDS) was used. To evaluate mechanical properties, hardness and microhardness measurements were performed. Investigations based on the microstructural features with the idea to indicate suitability of weld repair of the column were performed in this study. It was observed that the crack initiation, caused by oxidation/corrosion and thermal stresses induced by temperature gradient, appeared in the inner side of the tube wall and propagation occurred along grain boundaries. The results clearly showed the presence of an irregular microstructure which contributed to crack propagation through the tube wall. An occurrence of precipitated needle-shaped carbides/carbonitrides and brittle σ phase was also identified in the microstructure. Results of the microstructural and fracture analysis clearly indicate that reformer furnace columns made of heat resistant steel HK 40 were unsuitable for weld repair. KeywordsMrostructural evaluation; Fracture analysis; Steel HK40; Weld repair. Análisis micro estructural como indicador de la idoneidad de reparación por soldadura de aceros al Cr-Ni resistentes al calor ResumenLa evaluación metalúrgica se realizó en un tubo de columna con fracturas, que es parte del horno reformador en una planta de amoníaco. Estos tubos son fundidos centrífugamente y fabricados en acero resistente al calor, de tipo HK-40. Para el análisis microestructural de la fractura se ha utilizado microscopía óptica y electrónica de barrido (SEM). La composición de los micro-constituyentes se determinó por espectrometría de rayos X de energía dispersiva (EDS). Las propiedades mecánicas se evaluaron mediante mediciones de microdureza Vickers. Las investigaciones en este estudio se han llevado a cabo con el fin de demostrar la idoneidad de reparación por soldadura de columnas en base a sus características micro-estructurales. Se ha observado que el inicio de la rotura, causada por el efecto de la oxidación/corrosión y el choque térmico ocasionado por el gradiente de temperatura, aparece en la pared interna del tubo y se propaga a lo largo de los bordes de grano. Los resultados demuestran la presencia de una microestructura irregular que contribuyó a la propagación de la rotura a lo largo de la pared del tubo. En la microestructura también se ha registrado la formación da la precipitación de fases de carburo/carbón nitrito que aparecen en forma de agujas y fase σ frágil. Con base en los resultados obtenidos, se puede concluir que la microestructura investigada no es idónea para aplicar la reparación por soldadura. Palabras claveEvaluación microestructural; Análisis de fractura; Acero de tipo HK40; Reparación por soldadura.

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“…Since the early 1960s, steamreformer and pyrolysis tubes have been manufactured by centrifugal casting of such steels, of 25% Cr-20% Ni type (Bhaumik et al, 2002) or 25% Cr-35% Ni type (De Almeida et al, 2003). More recently, heat-resistant cast steels have been used for the manufacture of bulk superplastic forming (SPF) tools processed by sand-casting and machining (Montagnon et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Study and prevention of cracking during weld-repair of heat-resistant cast steels

Branza

Deschaux-Beaume

Sierra

et al. 2009

Journal of Materials Processing Technology

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Failure of reformer tube of an ammonia plant

Cited by 30 publications

References 0 publications

Effect of severe operation conditions on the degradation state of radiant coils in pyrolysis furnaces

Effect of severe operation conditions on the degradation state of radiant coils in pyrolysis furnaces

Microstructural analysis as the indicator for suitability of weld repairing of the heat resistant Cr - Ni steel

Study and prevention of cracking during weld-repair of heat-resistant cast steels

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