Retrofit of a 75T/H PC-Fired Boiler Into a Coal/Gas Co-Firing One

Author(s):  
Dazhui Wen ◽  
Donglin Chen ◽  
Huifang Xu

For full use of low heat value of coke oven gas and operation under conditions of coal, gas and coal/gas, a previously 75t/h PC-fired boiler was retrofitted: six gas burners with dual-passage were installed under the originally PC-fired burners and tangentially arranged with a larger combustion circle and declined axes; the pulverized coal fired burners were declined downward 8∼10° so as to control the flame center; the heating surface of slag cooling tube and economizer were extended. The operation and test after the retrofit showed that: the combustion was very stable and temperature of the superheated steam was between the normal range under all conditions of load and fuel; the maximum steam rate was 59t/h and temperature of the exhaust flue gas was lower than 160°C under gas condition while gas flow was at 26000 Nm3/h; the maximum steam rate was 81t/h and temperature of the exhaust flue gas was lower than 147°C under coal condition; the maximum steam rate was 77t/h and temperature of the exhaust flue gas was about 155°C under coal/gas condition.

2010 ◽  
Vol 4 (4) ◽  
pp. 491-497 ◽  
Author(s):  
Guoqiang Zhang ◽  
Lin Gao ◽  
Hongguang Jin ◽  
Rumou Lin ◽  
Sheng Li

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3860
Author(s):  
Mária Hagarová ◽  
Milan Vaško ◽  
Miroslav Pástor ◽  
Gabriela Baranová ◽  
Miloš Matvija

Corrosion of boiler tubes remains an operational and economic limitation in municipal waste power plants. The understanding of the nature, mechanism, and related factors can help reduce the degradation process caused by corrosion. The chlorine content in the fuel has a significant effect on the production of gaseous components (e.g., HCl) and condensed phases on the chloride base. This study aimed to analyze the effects of flue gases on the outer surface and saturated steam on the inner surface of the evaporator tube. The influence of gaseous chlorides and sulfates or their deposits on the course and intensity of corrosion was observed. The salt melts reacted with the steel surface facing the flue gas flow and increased the thickness of the oxide layer up to a maximum of 30 mm. On the surface not facing the flue gas flow, they disrupted the corrosive layer, reduced its adhesion, and exposed the metal surface. Beneath the massive deposits, a local overheating of the inner surface of the evaporator tubes occurred, which resulted in the release of the protective magnetite layer from the surface. Ash deposits reduce the boiler’s thermal efficiency because they act as a thermal resistor for heat transfer between the flue gases and the working medium in the pipes. The effect of insufficient feedwater treatment was evinced in the presence of mineral salts in the corrosion layer on the inner surface of the tube.


2021 ◽  
Vol 11 (7) ◽  
pp. 2961
Author(s):  
Nikola Čajová Kantová ◽  
Alexander Čaja ◽  
Marek Patsch ◽  
Michal Holubčík ◽  
Peter Ďurčanský

With the combustion of solid fuels, emissions such as particulate matter are also formed, which have a negative impact on human health. Reducing their amount in the air can be achieved by optimizing the combustion process as well as the flue gas flow. This article aims to optimize the flue gas tract using separation baffles. This design can make it possible to capture particulate matter by using three baffles and prevent it from escaping into the air in the flue gas. The geometric parameters of the first baffle were changed twice more. The dependence of the flue gas flow on the baffles was first observed by computational fluid dynamics (CFD) simulations and subsequently verified by the particle imaging velocimetry (PIV) method. Based on the CFD results, the most effective is setting 1 with the same boundary conditions as those during experimental PIV measurements. Setting 2 can capture 1.8% less particles and setting 3 can capture 0.6% less particles than setting 1. Based on the stoichiometric calculations, it would be possible to capture up to 62.3% of the particles in setting 1. The velocities comparison obtained from CFD and PIV confirmed the supposed character of the turbulent flow with vortexes appearing in the flue gas tract, despite some inaccuracies.


2020 ◽  
Vol 33 (2) ◽  
pp. 183
Author(s):  
Hongqing Feng ◽  
Zhirong Nan ◽  
Xinyi Wang ◽  
Weiwen Zhang

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