Formation of nitrogen oxides from fuel-N through HCN and NH3: a model-compound study

Hämäläinen, Jouni; Aho, Martti; Tummavuori, Jouni

doi:10.1016/0016-2361(94)90218-6

Cited by 83 publications

(41 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In a followup study with different model compounds of pyridine type, pyrrole type, and amino type, no such correlation could be found [28]. Neither could the results in this study establish any correlation between the HCN/NH 3 ratio and the O/N ratio of the model compounds and bark, at least if the whey particles were excluded (Fig.…”

Section: Discussioncontrasting

confidence: 69%

Formation of HNCO, HCN, and NH3 from the pyrolysis of bark and nitrogen-containing model compounds

Hansson

Samuelsson²,

Tullin³

et al. 2004

Combustion and Flame

306

213

View full text Add to dashboard Cite

Bark pellets have been pyrolyzed in a fluidized bed reactor at temperatures between 700 and 1000 • C. Identified nitrogen-containing species were hydrogen cyanide (HCN), ammonia (NH 3 ), and isocyanic acid (HNCO). Quantification of HCN and to some extent of NH 3 was unreliable at 700 and 800 • C due to low concentrations. HNCO could not be quantified with any accuracy at any temperature for bark, due to the low concentrations found. Since most of the nitrogen in biomass is bound in proteins, various protein-rich model compounds were pyrolyzed with the aim of finding features that are protein-specific, making conclusions regarding the model compounds applicable for biomass fuels in general. The model compounds used were a whey protein isolate, soya beans, yellow peas, and shea nut meal. The split between HCN and NH 3 depends on the compound and temperature. It was found that the HCN/NH 3 ratio is very sensitive to temperature and increases with increasing temperature for all compounds, including bark. Comparing the ratio for the different compounds at a fixed temperature, the ratio was found to decrease with decreasing release of volatile nitrogen. The temperature dependence implies that heating rate and thereby particle size affect the split between HCN and NH 3 . For whey, soya beans, and yellow peas, HNCO was also quantified. It is suggested that most HCN and HNCO are produced from cracking of cyclic amides formed as primary pyrolysis products. The dependence of the HNCO/HCN ratio on the compound is fairly small, but the temperature dependence of the ratio is substantial, decreasing with increasing temperature. The release of nitrogen-containing species does not seem to be greatly affected by the other constituents of the fuel, and proteins appear to be suitable model compounds for the nitrogen in biomass.

show abstract

Section: Discussioncontrasting

confidence: 69%

Formation of HNCO, HCN, and NH3 from the pyrolysis of bark and nitrogen-containing model compounds

Hansson

Samuelsson²,

Tullin³

et al. 2004

Combustion and Flame

306

213

View full text Add to dashboard Cite

show abstract

“…Ion potential analyses with the selective electrodes were usually used for measurement of NH 3 and HCN in the literatures [6,9,22] due to its easy operation and good reproducibility (±2.0%). Other producer gases collected in gas bags were identified and measured by the micro GC (Agilent GC 3000; Agilent Technologies Co.).…”

Section: Analysis Methodsmentioning

confidence: 99%

Fuel-N Evolution during the Pyrolysis of Industrial Biomass Wastes with High Nitrogen Content

Chen

Wang

et al. 2012

Energies

View full text Add to dashboard Cite

Abstract:In this study, sewage sludge and mycelial waste from antibiotic production were pyrolyzed in a batch scale fixed-bed reactor as examples of two kinds of typical industrial biomass wastes with high nitrogen content. A series of experiments were conducted on the rapid pyrolysis and the slow pyrolysis of these wastes in the temperature range from 500-800 °C to investigate the Fuel-N transformation behavior among pyrolysis products. The results showed that Fuel-N conversion to Char-N intimately depended on the pyrolysis temperature and the yield of Char-N reduced with the increase of the pyrolysis temperature. Under the same pyrolysis conditions, Tar-N production mainly depended on complex properties of the different biomasses, including volatile matter, nitrogen content and biomass functional groups. HCN was the predominant NO x precursor in the rapid pyrolysis of biomass, whereas in the slow pyrolysis of mycelial waste, more NH 3 was produced than HCN due to the additional NH 3 formation through the hydrogenation reaction of Char-N, HCN and H radicals. At the same time, some part of the char was analyzed by Fourier Transform infrared spectroscopy (FTIR) to get more information on the nitrogen functionality changes and the tar was also characterized by Gas Chromatography and Mass Spectrometry (GCMS) to identify typical nitrogenous tar compounds. Finally, the whole nitrogen distribution in products was discussed.

show abstract

“…In solid fuels fired systems, fuel-NO accounts for more than 80% of the total NO x and NO x is mainly produced by conversion of volatile nitrogen-containing species such as NH 3 and HCN, while remaining char-N oxidation in the reactor bed accounts for a minor part of the total NO [11,[17][18][19][20][21][22]. In addition, thermal NO x formation becomes important at temperatures above 1400 °C, which is far from the typical temperature range (800-1200 °C) of biomass combustion systems [16,23,24].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on NOx Reduction by Primary Measures in Biomass Combustion: Straw, Peat, Sewage Sludge, Forest Residues and Wood Pellets

2012

View full text Add to dashboard Cite

An experimental investigation was carried out to study the NO x formation and reduction by primary measures for five types of biomass (straw, peat, sewage sludge, forest residues/Grot, and wood pellets) and their mixtures. To minimize the NO x level in biomass-fired boilers, combustion experiments were performed in a laboratory scale multifuel fixed grate reactor using staged air combustion. Flue gas was extracted to measure final levels of CO, CO 2 , C x H y , O 2 , NO, NO 2 , N 2 O, and other species. The fuel gas compositions between the first and second stage were also monitored. The experiments showed good combustion quality with very low concentrations of unburnt species in the flue gas. Under optimum conditions, a NO x reduction of 50-80% was achieved, where the highest reduction represents the case with the highest fuel-N content. The NO x emission levels were very sensitive to the primary excess air ratio and an optimum value for primary excess air ratio was seen at about 0.9. Conversion of fuel nitrogen to NO x showed great dependency on the initial fuel-N content, where the blend with the highest nitrogen content had lowest conversion rate. Between 1-25% of the fuel-N content is converted to NO x depending on the fuel blend and excess air ratio. Sewage sludge is suggested as a favorable fuel to be blended with straw. It resulted in a higher NO x reduction and low fuel-N conversion to NO x . Tops and branches did not show desirable NO x reduction and made the combustion also more unstable. N 2 O emissions were very low, typically below 5 ppm at 11% O 2 in the dry flue gas, except for mixtures with high nitrogen content, where values up to 20 ppm were observed. The presented results are part of a larger study on OPEN ACCESSEnergies 2012, 5 271 problematic fuels, also considering ash content and corrosive compounds which have been discussed elsewhere.

show abstract

Formation of nitrogen oxides from fuel-N through HCN and NH3: a model-compound study

Cited by 83 publications

References 28 publications

Formation of HNCO, HCN, and NH3 from the pyrolysis of bark and nitrogen-containing model compounds

Formation of HNCO, HCN, and NH3 from the pyrolysis of bark and nitrogen-containing model compounds

Fuel-N Evolution during the Pyrolysis of Industrial Biomass Wastes with High Nitrogen Content

Experimental Investigation on NOx Reduction by Primary Measures in Biomass Combustion: Straw, Peat, Sewage Sludge, Forest Residues and Wood Pellets

Contact Info

Product

Resources

About