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x) Control
Published in Kenneth Schifftner, Air Pollution Control Equipment Selection Guide, 2021
Various combustion sources produce NOx. Boilers use a burner to combust the fuel and release heat. The heat boils water and generates steam. Larger boilers usually contain the water and steam inside tubes (water-tube boilers) surrounding a firebox. Some smaller boilers have a combustion tunnel surrounded by water (fire-tube boilers). The water-tube boiler has an analog in the petroleum refinery—the process heater.
Control of Nitrogen Oxides Emissions
Published in Jeff Kuo, Air Pollution Control Engineering for Environmental Engineers, 2018
An industrial/utility boiler consists of a firebox where the fuel is burned and the heat of the combustion gases is used to generate hot water or steam (Figure 8.4). Boilers can use virtually any fuel (e.g., natural gas, oil, or coal). Combustion temperatures are typically in the neighborhood of 3,500 °F (1,930 °C) (EPA, 2014).
Adaptive design and development of a modular water hyacinth briquette stove
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Oluwayomi J. Oyejide, Modestus O. Okwu, Lagouge K. Tartibu
The firebox also called the combustion chamber was incorporated in the design. The height of the combustion chamber is a very important parameter in stove design. The height of the firebox determines the burning time and level. It helps to rate the level of heat from the briquette that is channeled to cooking pot. The higher the reactor, the more pressure is needed to overcome the pressure exerted by the air. From calculations, height was obtained as 200 mm. Too long combustion chamber configured in one pot could result in clean combustion and lower efficiency of the stove since the pot distance is far from the burning flame from the briquette. The briquette stove was fabricated to be virtually adiabatic in such a way that heat loss is only possible through the chimney. It was also noted that the wider the cross-sectional area of the fire-box, the stronger the power output of the stove. Hence, uniform combustion can be achieved in this design by incorporating the fire-box in an inverted hollow shape rather than a square shaped. As shown in Figure 2c, the shape of the firebox was constructed to be an inverted cone with a height of about 200 mm which was opened at the sides so that the briquette fuel could be properly positioned. The stove design was adapted to meet established conditions. The full view of the designed stove is shown in Figure 3a,b.
Characterization of in-stack particulate emissions from residential wood hydronic heater appliances under different combustion conditions
Published in Journal of the Air & Waste Management Association, 2022
Jake Lindberg, Nicole Vitillo, Marilyn Wurth, Brian P. Frank, Shida Tang, Gil LaDuke, Patricia Mason Fritz, Rebecca Trojanowski, Thomas Butcher
In this study, we define the startup condition as the time period immediately following the addition of a fuel load into a hot firebox or coal bed. The definition of a fuel load is determined by the device. In the case of a Appliance 1, the fuel load is the amount of chips fed into the firebox by the device. For batch-fired appliances, such as Appliances 2 and 3, fuel loads are designated as an amount of cordwood corresponding to 120–160 kg/m3 firebox loading density. The exact test start time is determined by feed-screw actuation in the case of the chip unit, and by door closure following a fuel load addition in the case of the cordwood appliances. The startup period ends for a chip appliance when the unit indicates steady-state operation, and for a cordwood unit is defined as the period where the initial fuel charge burns down by 20%.
Investigation of real-life operating patterns of wood-burning appliances using stack temperature data
Published in Journal of the Air & Waste Management Association, 2020
Mahdi Ahmadi, Josh Minot, George Allen, Lisa Rector
At all times, the boiler is either heating the system water (in-use), or it is not (not-in-use). In-use and not-in-use modes are readily distinguishable in the temperature time series. When the boiler is in the in-use mode, the stack temperature fluctuates considerably, while in the not-in-use mode it remains flat. These usage modes are shown in Figure 2. The first pattern shows the semi-regular cycling of temperature due to the operation of the automatic air damper. A thermostat inside the building controls the call for heat by adjusting the pumps circulating hot water from the water jacket that surrounds the burner. An aquastat maintains the water temperature between set ranges. When the water temperature falls below the set range, an air damper opens, igniting the fire. The damper stays open until the temperature of the water jacket reaches the upper-temperature range. The aquastat controls lead to cyclical variations of temperatures in the boiler firebox and stack.