NO and N2O Emissions during Devolatilization and Char Combustion of a Single Biomass Particle under Oxy-fuel Conditions at Fluidized Bed Temperature

2017 ◽  
Vol 31 (7) ◽  
pp. 7157-7165 ◽  
Author(s):  
Hao Zhou ◽  
Yuan Li ◽  
Ning Li ◽  
Runchao Qiu ◽  
Kefa Cen
Keyword(s):  
Fluidized Bed ◽  
N2o Emissions ◽  
Char Combustion ◽  
Bed Temperature

An Experimental Study of the Gaseous Pollution Emissions in Petroleum-Coke-Fired Fluidized Beds

2003 ◽  
Author(s):  
Chun-Lin Zhang ◽  
Gui-Cheng Yuan ◽  
De-Chang Liu ◽  
Han-Ping Chen ◽  
Ding-Yu Liu ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Petroleum Coke ◽  
Calorific Value ◽  
Excess Oxygen ◽  
N2o Emissions ◽  
Bed Temperature ◽  
High Sulfur Content ◽  
Bubbling Fluidized Bed ◽  
Pollution Emissions ◽  
Gaseous Pollution

Petroleum cokes have high calorific value (about 37 MJkg−1), high sulfur content (2–7% wt.), and high nitrogen content (1∼3% wt.), introducing serious environmental problems when using as fuel. In this paper the effects of operating parameters (bed temperature, Ca/S mole ratio, and excess oxygen) on gaseous pollutant (SO2, NO, and N2O) emissions in a well-controlled bench scale fluidized bed reactor and an 1t/h bubbling fluidized bed for different type of petroleum cokes. Finally, the pollution emission differences between petroleum coke and coal were compared and the reasons were analyzed.

NO x and N2O Emissions During Fluidized Bed Combustion of Leather Wastes

2005 ◽  
Vol 128 (2) ◽  
pp. 99-103 ◽  
Author(s):  
Alberto Bahillo ◽  
Lourdes Armesto ◽  
Andrés Cabanillas ◽  
Juan Otero
Keyword(s):  
Nitrogen Content ◽  
Fluidized Bed ◽  
Oxygen Content ◽  
N2o Emission ◽  
N2o Emissions ◽  
Fluidized Bed Combustion ◽  
High Nitrogen Content ◽  
High Nitrogen ◽  
Leather Wastes ◽  
Leather Waste

Transformation of hide (animal skins) into leather is a complicated process during which significant amounts of wastes are generated. Fluidized bed combustion has been extended to burn different wastes that have problems with their disposal showing its technical feasibility. Considering the characteristics of the leather waste, especially the heating value (12.5-21MJ∕kg), it is a fairly good fuel. Moreover, leather waste has a high volatile matter, 65%, similar to other biomasses and unusual high nitrogen content, 14%. The aim of this work was to study leather wastes combustion in fluidized bed presenting experimental results regarding NOx and N2O emissions. A series of experiments were carried out in a fluidized bed pilot plant to understand the importance of operating parameters such as furnace temperature, oxygen content in gases, staged combustion and residence time on the NOx and N2O emission level. Despite having high nitrogen content, low conversion of N-fuel to NOx and N2O was measured during the combustion of leather waste in BFB. Bed temperature and oxygen content were found as the most important single parameters on N2O emission and only oxygen content has a significant influence on NOx emission. Leather waste exhibits a great NOx∕O2 trend; NOx emission decreases as the oxygen concentration decreases while the effect of combustion temperature on NOx is insignificant. Staged combustion does not give a reduction in NOx.

The Local Heat Balance in a Stationary Fluidized-Bed Furnace Burning Biomass Fuels

2003 ◽  
Author(s):  
Fredrik Niklasson ◽  
Filip Johnsson
Keyword(s):  
Fluidized Bed ◽  
Combustion Rate ◽  
Heat Balance ◽  
Circulating Fluidized Bed ◽  
Local Heat ◽  
Splash Zone ◽  
Two Phase ◽  
Bed Temperature ◽  
Temperature Constant ◽  
The Vertical Distribution

This work investigates the influence of biomass fuel properties on the local heat balance in a commercial-scale fluidized bed furnace. Experiments with different wood based fuels were performed in the Chalmers 12 MWth circulating fluidized bed boiler, temporarily modified to run under stationary conditions. A two-phase flow model of the bed and splash zone is applied, where the combustion rate in the bed is estimated by global kinetic expressions, limited by gas exchange between oxygen-rich bubbles and a fuel-rich emulsion phase. The outflow of bubbles from the bed is treated as “ghost bubbles” in the splash zone, where the combustion rate is determined from turbulent properties. It is found that a large amount of heat is required for the fuel and air to reach the temperature of the bed, in which the heat from combustion is limited by a low char content of the fuel. This implies that a substantial fraction of the heat from combustion of volatiles in the splash zone has to be transferred back to the bed to keep the bed temperature constant. It is concluded that the moisture content of the fuel does not considerably alter the vertical distribution of heat emitted, as long as the bed temperature is kept constant by means of flue gas recycling.

The Pyrocarbon Deposition Techniques of Mechanical Heart Valve Prostheses

2011 ◽  
Vol 464 ◽  
pp. 749-752 ◽  
Author(s):  
Jian Hui Zhang ◽  
Xin Chen
Keyword(s):  
Fluidized Bed ◽  
Heart Valve ◽  
Gas Flow ◽  
Mechanical Heart Valve ◽  
Carbon Matrix ◽  
Artificial Heart Valve ◽  
Bed Temperature ◽  
Wide Range ◽  
Isotropic Carbon ◽  
Deposition Conditions

The structure and property of pyrocarbon varies widely with different deposition conditions. The isotropic carbon which can only been deposited in the bed of fluidized particles is very important in biomedical fields, for instance, it is often used as the coating of artificial heart valve components. The deposition of isotropic pyrocarbon containing silicon is experimented in fluidized bed over a wide range of deposition conditions. The results show that bed temperature influences strongly average coating rate, coating density, silicon content and coating micro-hardness. Propane concentration has a much effect on coating density, carbon matrix density and isotropic characteristics. Total gas flow rate and inlet dimension of fluidized bed affect the formation of fluidized bed.

Effect of bed temperature on bubble size and bubble rising velocity in a semi-cylindrical slugging fluidized bed.

1990 ◽  
Vol 23 (6) ◽  
pp. 765-767 ◽  
Author(s):  
Yasuo Hatate ◽  
Kazuya Ijichi ◽  
Yoshimitsu Uemura ◽  
Mitsunobu Migita ◽  
Desmond F. King
Keyword(s):  
Fluidized Bed ◽  
Bubble Size ◽  
Bed Temperature ◽  
Bubble Rising ◽  
Bubble Rising Velocity

scholarly journals Heat transfer to a moving wire immersed in a gas fluidized bed furnace

2021 ◽  
Author(s):  
Antonio Tannas
Keyword(s):  
Heat Transfer ◽  
Fluidized Bed ◽  
Steel Wire ◽  
Transfer Rates ◽  
New Correlation ◽  
Bed Temperature ◽  
Molten Lead ◽  
The Difference ◽  
Considerable Work ◽  
Work Done

In order to replace hazardous molten lead baths in the heat treatment of carbon steel wire with environmentally friendly fluidized bed furnaces a better understanding is needed of their heat transfer rates. There has been considerable work done in examining heat transfer rates to large cylinders immersed in fluidized beds, and some on wire sized ones as well, but all previous studies have been conducted on static cylinders. In order to gain a deeper understanding of heat transfer rates to a moving wire immersed in a fluidized bed furnace an apparatus has been constructed to move a wire through a fluidized bed. The heat transfer rates were calculated using the difference in inlet and outlet temperatures, wire speed and the bed temperature. As predicted, correlations for static wire were found to under-predict heat transfer rates at higher wire speeds, so a new correlation was developed by modifying an existing one.

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