NO and N2O Formation/Decomposition Characteristics During Co-Combustion of Coal With Biomass

2005 ◽  
Author(s):  
Asri Gani ◽  
Ichiro Naruse
Keyword(s):  
Coal Combustion ◽  
Co2 Emission ◽  
N2o Emission ◽  
Reaction Scheme ◽  
Volatile Matter ◽  
N2o Emissions ◽  
Emission Characteristics ◽  
Homogeneous Reaction ◽  
Fuel Cost ◽  
N2o Formation

Co-combustion technologies of coal with biomass have been applied in many practical coal combustion boilers in order to reduce CO2 emission, fuel cost and so forth. Furthermore, the biomass may be able to enhance the combustion performance and to control NOx and N2O emissions since the biomass contains high volatile matter and evolves NH3 as the main volatile N-species. This study focuses on NOx and N2O emission characteristics during co-combustion of coal with biomass. The main results obtained show that emission amount of NO and N2O during co-combustion is relatively more than that during coal combustion. At least, NO behavior can be simulated by the homogeneous reaction scheme relating to NOx even at constant temperature. However, the N2O behavior will be influenced by heterogeneous schemes due to char particles during co-combustion.

The NOx and N2O Emission Characteristics of an HCCI Engine Operated With N-Heptane

2007 ◽  
Author(s):  
Hailin Li ◽  
W. Stuart Neill ◽  
Hongsheng Guo ◽  
Wally Chippior
Keyword(s):  
N2o Emission ◽  
Combustion Efficiency ◽  
N2o Emissions ◽  
Emission Characteristics ◽  
Nox Emissions ◽  
Fuel Injector ◽  
Incomplete Combustion ◽  
Hcci Combustion ◽  
Wide Range ◽  
Combustion Phase

This paper presents the NOx and N2O emission characteristics of a Cooperative Fuel Research (CFR) engine modified to operate in Homogeneous Charge Compression Ignition (HCCI) combustion mode using an air-assist port fuel injector. The single-cylinder engine was fuelled with n-heptane for these experiments. The parameters examined include intake air temperature and pressure, air/fuel ratio, compression ratio, and exhaust gas recirculation (EGR) rate. The parameters were varied in order to change the combustion phasing from advanced (knocking) to retarded (incomplete combustion) conditions. NOx emissions were less than 5 ppm for a fairly wide range of combustion phases, except when knocking or incomplete combustion occurred, and were largely unaffected by the parameter varied when the combustion phase was within the acceptable range. It was also found that NOx emissions increased significantly when retarded and incomplete combustion was observed even though lower combustion temperatures were expected. The increased N2O and unburned hydrocarbon (THC) emissions usually observed with retarded combustion phasing, as well as the deteriorated combustion efficiency, may contribute to this unexpected increase in NOx emissions. It was also shown that N2O emissions were extremely low (less than 0.5 ppm) except when incomplete combustion was observed.

scholarly journals The NOx and N2O Emission Characteristics of an HCCI Engine Operated With n-Heptane

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Hailin Li ◽  
W. Stuart Neill ◽  
Hongsheng Guo ◽  
Wally Chippior
Keyword(s):  
N2o Emission ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
N2o Emissions ◽  
Emission Characteristics ◽  
Nox Emissions ◽  
Oxides Of Nitrogen ◽  
Incomplete Combustion ◽  
Hcci Combustion ◽  
Wide Range

This paper presents the oxides of nitrogen (NOx) and nitrous oxide (N2O) emission characteristics of a Cooperative Fuel Research (CFR) engine modified to operate in homogeneous charge compression ignition (HCCI) combustion mode. N-heptane was used as the fuel in this research. Several parameters were varied, including intake air temperature and pressure, air/fuel ratio (AFR), compression ratio (CR), and exhaust gas recirculation (EGR) rate, to alter the HCCI combustion phasing from an overly advanced condition where knocking occurred to an overly retarded condition where incomplete combustion occurred with excessive emissions of unburned hydrocarbons (UHC) and carbon monoxide (CO). NOx emissions below 5 ppm were obtained over a fairly wide range of operating conditions, except when knocking or incomplete combustion occurred. The NOx emissions were relatively constant when the combustion phasing was within the acceptable range. NOx emissions increased substantially when the HCCI combustion phasing was retarded beyond the optimal phasing even though lower combustion temperatures were expected. The increased N2O and UHC emissions observed with retarded combustion phasing may contribute to this unexpected increase in NOx emissions. N2O emissions were generally less than 0.5 ppm; however, they increased substantially with excessively retarded and incomplete combustion. The highest measured N2O emissions were 1.7 ppm, which occurred when the combustion efficiency was approximately 70%.

scholarly journals Effects of Environmental Drivers and Agricultural Management on Soil CO2 and N2O Emissions

Agronomy ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 54
Author(s):  
Márton Dencső ◽  
Ágota Horel ◽  
Igor Bogunovic ◽  
Eszter Tóth
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Co2 Emission ◽  
Laboratory Experiments ◽  
Ghg Emissions ◽  
N2o Emission ◽  
Agricultural Management ◽  
Environmental Drivers ◽  
N2o Emissions

Understanding the roles of natural drivers and anthropogenic activities in greenhouse gas (GHG) emissions of arable fields is crucial for adopting the most appropriate agricultural management. This study investigated the effect of two tillage treatments of mouldboard ploughing (MP) and no-tillage (NT), and the environmental factors (soil water content and temperature, carbon content and nitrogen forms) on soil carbon dioxide (CO2) and nitrous oxide (N2O) emissions. The research was conducted on chernozem soil under winter wheat cultivation. Besides field monitoring, several laboratory experiments took place to examine the effects of environmental drivers and fertilization management on soil GHG emissions. We observed no significant difference between the CO2 emission of MP and NT during a full year period. Nevertheless, significant differences were found in the sub-periods (more particularly during vegetation and then after harvest). NT had higher CO2 emission than MP in all laboratory experiments (p < 0.001) and in the after harvest period of the field trial, measured on bare soil (p < 0.0001). NT had significantly higher N2O emission both under laboratory (p < 0.0001) and field conditions (p < 0.0081). Different fertilization showed no distinguishable effect on N2O emission in the laboratory. This study confirms that N2O emission of the arable field depended more on soil water content than soil temperature, and vice-versa for CO2 emission.

scholarly journals Nitrous Oxide Emissions in Pineapple Cultivation on a Tropical Peat Soil

2021 ◽  
Vol 13 (9) ◽  
pp. 4928
Author(s):  
Alicia Vanessa Jeffary ◽  
Osumanu Haruna Ahmed ◽  
Roland Kueh Jui Heng ◽  
Liza Nuriati Lim Kim Choo ◽  
Latifah Omar ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Soil Temperature ◽  
Peat Soil ◽  
Farming Systems ◽  
N2o Emission ◽  
Nitrous Oxide Emissions ◽  
Natural State ◽  
N2o Emissions ◽  
Wet Season ◽  
Peat Soils

Farming systems on peat soils are novel, considering the complexities of these organic soil. Since peat soils effectively capture greenhouse gases in their natural state, cultivating peat soils with annual or perennial crops such as pineapples necessitates the monitoring of nitrous oxide (N2O) emissions, especially from cultivated peat lands, due to a lack of data on N2O emissions. An on-farm experiment was carried out to determine the movement of N2O in pineapple production on peat soil. Additionally, the experiment was carried out to determine if the peat soil temperature and the N2O emissions were related. The chamber method was used to capture the N2O fluxes daily (for dry and wet seasons) after which gas chromatography was used to determine N2O followed by expressing the emission of this gas in t ha−1 yr−1. The movement of N2O horizontally (832 t N2O ha−1 yr−1) during the dry period was higher than in the wet period (599 t N2O ha−1 yr−1) because of C and N substrate in the peat soil, in addition to the fertilizer used in fertilizing the pineapple plants. The vertical movement of N2O (44 t N2O ha−1 yr−1) was higher in the dry season relative to N2O emission (38 t N2O ha−1 yr−1) during the wet season because of nitrification and denitrification of N fertilizer. The peat soil temperature did not affect the direction (horizontal and vertical) of the N2O emission, suggesting that these factors are not related. Therefore, it can be concluded that N2O movement in peat soils under pineapple cultivation on peat lands occurs horizontally and vertically, regardless of season, and there is a need to ensure minimum tilling of the cultivated peat soils to prevent them from being an N2O source instead of an N2O sink.

scholarly journals The interaction of seasonal rainfall and nitrogen fertiliser rate on soil N2O emission, total N loss and crop yield of dryland sorghum and sunflower grown on sub-tropical Vertosols

Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 604 ◽  
Author(s):  
G. D. Schwenke ◽  
B. M. Haigh
Keyword(s):  
Crop Yield ◽  
Crop Production ◽  
Field Experiments ◽  
N2o Emission ◽  
N2o Emissions ◽  
N Loss ◽  
N Losses ◽  
Total N ◽  
Tropical Regions ◽  
The Impact

Summer crop production on slow-draining Vertosols in a sub-tropical climate has the potential for large emissions of soil nitrous oxide (N2O) from denitrification of applied nitrogen (N) fertiliser. While it is well established that applying N fertiliser will increase N2O emissions above background levels, previous research in temperate climates has shown that increasing N fertiliser rates can increase N2O emissions linearly, exponentially or not at all. Little such data exists for summer cropping in sub-tropical regions. In four field experiments at two locations across two summers, we assessed the impact of increasing N fertiliser rate on both soil N2O emissions and crop yield of grain sorghum (Sorghum bicolor L.) or sunflower (Helianthus annuus L.) in Vertosols of sub-tropical Australia. Rates of N fertiliser, applied as urea at sowing, included a nil application, an optimum N rate and a double-optimum rate. Daily N2O fluxes ranged from –3.8 to 2734g N2O-Nha–1day–1 and cumulative N2O emissions ranged from 96 to 6659g N2O-Nha–1 during crop growth. Emissions of N2O increased with increased N fertiliser rates at all experimental sites, but the rate of N loss was five times greater in wetter-than-average seasons than in drier conditions. For two of the four experiments, periods of intense rainfall resulted in N2O emission factors (EF, percent of applied N emitted) in the range of 1.2–3.2%. In contrast, the EFs for the two drier experiments were 0.41–0.56% with no effect of N fertiliser rate. Additional 15N mini-plots aimed to determine whether N fertiliser rate affected total N lost from the soil–plant system between sowing and harvest. Total 15N unaccounted was in the range of 28–45% of applied N and was presumed to be emitted as N2O+N2. At the drier site, the ratio of N2 (estimated by difference)to N2O (measured) lost was a constant 43%, whereas the ratio declined from 29% to 12% with increased N fertiliser rate for the wetter experiment. Choosing an N fertiliser rate aimed at optimum crop production mitigates potentially high environmental (N2O) and agronomic (N2+N2O) gaseous N losses from over-application, particularly in seasons with high intensity rainfall occurring soon after fertiliser application.

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.

Parametric study of N2O formation in coal combustion

Fuel ◽  
1992 ◽  
Vol 71 (1) ◽  
pp. 9-14 ◽  
Author(s):  
J.A.Oude Lohuis ◽  
P.J.J. Tromp ◽  
J.A. Moulijn
Keyword(s):  
Parametric Study ◽  
Coal Combustion ◽  
N2o Formation

scholarly journals Water Salinity Should Be Reduced for Irrigation to Minimize Its Risk of Increased Soil N2O Emissions

2018 ◽  
Vol 15 (10) ◽  
pp. 2114 ◽  
Author(s):  
Qi Wei ◽  
Junzeng Xu ◽  
Linxian Liao ◽  
Yawei Li ◽  
Haiyu Wang ◽  
...  
Keyword(s):  
Saline Water ◽  
N2o Emission ◽  
Salinity Level ◽  
N2o Emissions ◽  
Low Salinity ◽  
Nitrogen Inputs ◽  
Salinity Levels ◽  
N2o Fluxes ◽  
Moisture Dynamics ◽  
Irrigated Soils

To reveal the effect of irrigation salinity on soil nitrous oxide (N2O) emission, pot experiments were designed with three irrigation salinity levels (NaCl and CaCl2 of 1, 2.5 and 4 g/L equivalence, Ec = 3.6, 8.1 and 12.7 ds/m), either for 0 kg N/ha (N0) or 120 kg N/ha (N120) nitrogen inputs. N2O emissions from soils irrigated at different salinity levels varied in a similar pattern which was triggered by soil moisture dynamics. Yet, the magnitudes of pulse N2O fluxes were significantly varied, with the peak flux at 5 g/L irrigation salinity level being much higher than at 2 and 8 g/L. Compared to fresh water irrigated soils, cumulative N2O fluxes were reduced by 22.7% and 39.6% (N0), 29.1% and 39.2% (N120) for soils irrigated with 2 and 8 g/L saline water, while they were increased by 87.7% (N0) and 58.3% (N120) for soils irrigated with 5 g/L saline water. These results suggested that the effect degree of salinity on consumption and production of N2O might vary among irrigation salinity ranges. As such, desalinating brackish water to a low salinity level (such as 2 g/L) before it is used for irrigation might be helpful for solving water resources crises and mitigating soil N2O emissions.

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