Failure Analysis of Steel Superheater Tube Fractured in a Boiler of a Power Plant

2011 ◽  
Vol 462-463 ◽  
pp. 467-471
Author(s):  
Zainul Huda

This paper presents a case study of ASME SA213 type-T22 alloy steel superheater tube that failed in a boiler of a power plant. The failed superheater tube was investigated by visual examination, metallography, optical microscopy, electron fractography, and hardness testing. Microscopic examinations revealed inclusion, pre-existing micro-cracks and cementite precipitates at the grain boundaries in the microstructure; which were thought to be one of the major causes of failure of the superheater tube. Another major cause failure of boiler type T-22 was found to be creep failure because the boiler had been under use for a long time (36573 hours) at high steam temperature of around 420 °C with 130 bar pressure. Finally, recommendations have been suggested to improve the material characteristics and properties of the superheater tube for application in boiler of the power plant.

2020 ◽  
Vol 46 (2) ◽  
pp. 87-92
Author(s):  
Eugenius Pradipto ◽  
Syam Rachma Marcillia ◽  
Nabila Afif ◽  
Swari Dewanti Hamastuti ◽  
Natasha Nurul Annisa

Bamboo has been used for a long time as a material for simple to complex structures. Many advantages of bamboo as a building material makes it suitable for buildings in disaster-prone areas. Bamboo is however prone to humidity, which could cause fungi and moss to emerge and endanger the building structure. Pedestal foundation made of concrete or stone is often used to reduce this risk as for its action as a barrier of direct contact between soil and bamboo. Nevertheless, water from damp soil or rainwater can still penetrate the foundation by capillary transmission through the foundation’s pores. This research proposed a hollow pedestal foundation model with larger pores and compared its ability to reduce moisture on bamboo columns to an ordinary pedestal foundation. The case study is a temporary post-disaster housing project of 13 houses in Muntilan, Central Java, Indonesia, which was built on an active rice field. Visual examination showed that after 5 years of occupancy, bamboo houses built on hollow pedestal foundations still firmly stood without apparent attacks of fungi or overgrowing mold, whereas the moisture measurement showed that the usage of hollow pedestal foundation could reduce the humidity level in the bamboo column almost twice as fast compared to solid pedestal foundation.


Author(s):  
Jun-Xian Fu ◽  
Shukri Souri ◽  
James S. Harris

Abstract Temperature and humidity dependent reliability analysis was performed based on a case study involving an indicator printed-circuit board with surface-mounted multiple-die red, green and blue light-emitting diode chips. Reported intermittent failures were investigated and the root cause was attributed to a non-optimized reflow process that resulted in micro-cracks and delaminations within the molding resin of the chips.


Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1581
Author(s):  
Deepak Kumar Gupta ◽  
Amitkumar V. Jha ◽  
Bhargav Appasani ◽  
Avireni Srinivasulu ◽  
Nicu Bizon ◽  
...  

The automatic load frequency control for multi-area power systems has been a challenging task for power system engineers. The complexity of this task further increases with the incorporation of multiple sources of power generation. For multi-source power system, this paper presents a new heuristic-based hybrid optimization technique to achieve the objective of automatic load frequency control. In particular, the proposed optimization technique regulates the frequency deviation and the tie-line power in multi-source power system. The proposed optimization technique uses the main features of three different optimization techniques, namely, the Firefly Algorithm (FA), the Particle Swarm Optimization (PSO), and the Gravitational Search Algorithm (GSA). The proposed algorithm was used to tune the parameters of a Proportional Integral Derivative (PID) controller to achieve the automatic load frequency control of the multi-source power system. The integral time absolute error was used as the objective function. Moreover, the controller was also tuned to ensure that the tie-line power and the frequency of the multi-source power system were within the acceptable limits. A two-area power system was designed using MATLAB-Simulink tool, consisting of three types of power sources, viz., thermal power plant, hydro power plant, and gas-turbine power plant. The overall efficacy of the proposed algorithm was tested for two different case studies. In the first case study, both the areas were subjected to a load increment of 0.01 p.u. In the second case, the two areas were subjected to different load increments of 0.03 p.u and 0.02 p.u, respectively. Furthermore, the settling time and the peak overshoot were considered to measure the effect on the frequency deviation and on the tie-line response. For the first case study, the settling times for the frequency deviation in area-1, the frequency deviation in area-2, and the tie-line power flow were 8.5 s, 5.5 s, and 3.0 s, respectively. In comparison, these values were 8.7 s, 6.1 s, and 5.5 s, using PSO; 8.7 s, 7.2 s, and 6.5 s, using FA; and 9.0 s, 8.0 s, and 11.0 s using GSA. Similarly, for case study II, these values were: 5.5 s, 5.6 s, and 5.1 s, using the proposed algorithm; 6.2 s, 6.3 s, and 5.3 s, using PSO; 7.0 s, 6.5 s, and 10.0 s, using FA; and 8.5 s, 7.5 s, and 12.0 s, using GSA. Thus, the proposed algorithm performed better than the other techniques.


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