• Journal of the Korean Society of Safety
• /
• v.19 no.4 s.68
• /
• pp.14-19
• /
• 2004

Boiler is a hazardous equipment to have potential explosion ail the time. And not only it has malfunction at explosion. it lead to people death but also secondary accident such as explosion and fire. Therefore, this equipment should not be broken for keeping its own function. And also, high level of safety should be kept in the process of the use not to be malfunctioned. A large scale of accident due to boiler explosion can be preventive in advance. Boiler fracture is occurred by instant expansion (approximately 1700 time) from quick evaporation of rater in boiler, due to pressure decrease in boiler Emitting energy from it is tremendous and it is so dangerous because of its high temperature. Secondary explosion such as fire is also a main hazard occurring at fuel supply place. If any devices with high pressure is broken, then not only boiler vessel but also components of it are spread with high speed, causing secondary accident. This study is to analyze integrally accident cause of fire and flue tube boiler to have occurred pressure fracture actually, to show countermeasures to prevent accident loss from the fire and flue tube boiler.

• 한국태양에너지학회:학술대회논문집
• /
• 2009.11a
• /
• pp.259-264
• /
• 2009

Most of the fossil power plants firing lower grade coals are challenged with maintaining good combustion conditions while maximizing generation and minimizing emissions. In many cases significant derate, availability losses and increase in unburned carbon levels can be attributed to poor combustion conditions as a result of poorly controlled local fuel and air distribution within the boiler furnace. The poor combustion conditions are directly related to the gas flow deviation in upper furnace and convection tube-bank but a less reported issue related to in large-scale oppose wall fired boilers. In order to develop a on-line combustion monitoring system and suggest an alternative heat flux estimation method at tube bank, which is very useful information for boiler design tool and blower optimizing system, field test was conducted at operating power boiler. During the field test the exhaust gases' temperature and tube metal temperature were monitored by using a spatially distributed sensors grid which located in the boiler's high temperature vestibule region. At these locations. the flue gas flow is still significantly stratified, and air in-leakage is minimal which enables tracing of poor combustion zones to specific burners and over-fire air ports. Test results showed that the flue gas monitoring method is more proper than metal temperature distribution monitoring for real time combustion monitoring because tube metal temp. distribution monitoring method is related to so many variables such as flue gas, internal flow unbalance, spray etc., Heat flux estimation at the tube bank with flue gas temp. and metal temp. data can be alternative method when tube drilling type sensor can't able to use.

• Proceedings of the KSME Conference
• /
• 2004.11a
• /
• pp.1686-1691
• /
• 2004

The effect of recirculated exhaust gas on performance and exhaust emissions with FGR rate are investigated by using a natural circulation, pressurized draft and water tube boiler with FGR system operating at several boiler loads and over fire air(OFA) damper openings. The purpose of this study is to apply the FGR system to a power plant boiler for reducing $NO_{x}$ emissions. To activate the combustion, the suction damper of two stage combustion system installed in the upper side of wind box is opened by handling the lever between $0^{\circ}$ and $90^{\circ}$ , and the OFA with 0 to 20% into the flame is supplied, as the combustion air supplied to burner is reduced. It is found that the fuel consumption rate divided by evaporation rate does not show an obvious tendency to increase or decrease with rising the FOR rate, and $NO_{x}$ emissions are decreased, at the same OF A damper opening, as FOR rates are elevated and boiler loads are dropped.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.40 no.4
• /
• pp.263-273
• /
• 2016

The effect of recirculated exhaust gas on performance and exhaust emissions with FGR rate are investigated by using a natural circulation, pressurized draft and water tube boiler with FGR system operating at several boiler loads and over fire air damper openings. The purpose of this study is to apply the FGR system to a power plant boiler for reducing $NO_x$ emissions. To activate the combustion, the OFA with 0 to 20% is supplied into the flame. When the suction damper of two stage combustion system installed in the upper side of wind box is opened by handling the lever between $0^{\circ}$ and $90^{\circ}$, also, the combustion air supplied to burner is changed. It is found that the fuel consumption rate per evaporation rate did not show an obvious tendency to increase or decrease with rising the FGR rate, and $NO_x$ emissions at the same OFA damper opening are decreased, as FGR rates are elevated and boiler loads are dropped. While a trace amount of soot is emitted without regard to the operation conditions of boiler load, OFA damper opening and FGR rate, because soot emissions are eliminated by the electrostatic precipitator with a collecting efficiency of 86.7%.