Effect of heterogeneous mechanisms during reburning of nitrogen oxide

Chen, Wei-Yin; Ma, Long

doi:10.1002/aic.690420717

Cited by 63 publications

(36 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Table 1 show that the raw lignite char after pyrolysis has a much higher surface area than bituminous coal char, either by BETN, or by DWCO, method. Since NO reduction by lignite char in the absence of CO, and 0, is less severe than that by bituminous coal char (see data in Figure 1, to be discussed in the subsequent section), this observation confirms our earlier claim (Chen and Ma, 1995) that surface area is not a normalization factor of char reactivity. Indeed, as we will discuss later in this report, the effectiveness of heterogeneous reburning depends on: (1) the origin of char, (2) char devolatilization temperature and time, and (3) the competitions of NO with CO, and 0, for the active sites on the char surface.…”

Section: A Pore Structure Analyses and Their Implicationssupporting

confidence: 79%

“…(1991a,b). The detailed char preparation procedure has been documented in our sixth quarterly report (Chen et a/., 1995a). .…”

Section: Work Accomplishedmentioning

confidence: 99%

“…(Chen and Ma, 1995;Chen et al, 1995a;Chen et al, 1995b). Figures 12 and 13 present the exit NO concentrations observed in these two series of experiments.…”

Section: B Effects Of Pyrolysis Time On Char Reactivitymentioning

confidence: 99%

“…In the early period ofthis project (Chen and Ma, 1995;Chen et al, 1995aChen et al, , 1995b, we have been examining the reactivities of selected chars with NO. The effects of reactive gaseous species which typically exist in reburning environment, including CO,, 0, and CO, have been investigated sequentially.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Role of char during reburning of nitrogen oxides. Tenth quarterly report, January 1, 1996--March 31, 1996

Chen¹,

Lu²,

Tang³

et al. 1996

Self Cite

View full text Add to dashboard Cite

Section: A Pore Structure Analyses and Their Implicationssupporting

confidence: 79%

“…(1991a,b). The detailed char preparation procedure has been documented in our sixth quarterly report (Chen et a/., 1995a). .…”

Section: Work Accomplishedmentioning

confidence: 99%

“…(Chen and Ma, 1995;Chen et al, 1995a;Chen et al, 1995b). Figures 12 and 13 present the exit NO concentrations observed in these two series of experiments.…”

Section: B Effects Of Pyrolysis Time On Char Reactivitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Role of char during reburning of nitrogen oxides. Tenth quarterly report, January 1, 1996--March 31, 1996

Chen¹,

Lu²,

Tang³

et al. 1996

Self Cite

View full text Add to dashboard Cite

“…The global reaction scheme is used to depict the NO formation and destruction process in the reburn zone. The reactions considered are, 1) Hydrocarbon (HC) reduction: Chen et al, 1996 CH NO HCN products x + → + …”

Section: ( ) ( )mentioning

confidence: 99%

Co-Firing Coal: Feedlot and Litter Biomass (Cfb and Clb) Fuels in Pulverized Fuel and Fixed Bed Burners

Annamalai¹,

Sweeten²,

Mukhtar³

et al. 2003

View full text Add to dashboard Cite

Intensive animal feeding operations create large amounts of animal waste that must be safely disposed of in order to avoid environmental degradation. Cattle feedlots and chicken houses are two examples. In feedlots, cattle are confined to small pens and fed a high calorie grain-diet diet in preparation for slaughter. In chicken houses, thousands of chickens are kept in close proximity. In both of these operations, millions of tons of manure are produced every year. The manure could be used as a fuel by mixing it with coal in a 90:10 blend and firing it in an existing coal suspension fired combustion systems. This technique is known as co-firing, and the high temperatures produced by the coal will allow the biomass to be completely combusted. Reburn is a process where a small percentage of fuel called reburn fuel is injected above the NO x producing, conventional coal fired burners in order to reduce NO x . The manure could also be used as reburn fuel for reducing NO x in coal fired plants. An alternate approach of using animal waste is to adopt the gasification process using a fixed bed gasifier and then use the gases for firing in gas turbine combustors. In this report, the cattle manure is referred to as feedlot biomass (FB) and chicken manure as litter biomass (LB). The report generates data on FB and LB fuel characteristics. Co-firing, reburn, and gasification tests of coal, FB, LB, coal: FB blends, and coal: LB blends and modeling on cofiring, reburn systems and economics of use of FB and LB have also been conducted. The biomass fuels are higher in ash, lower in heat content, higher in moisture, and higher in nitrogen and sulfur (which can cause air pollution) compared to coal. Small-scale cofiring experiments revealed that the biomass blends can be successfully fired, and NO x emissions will be similar to or lower than pollutant emissions when firing coal. Further experiments showed that biomass is twice or more effective than coal when used in a reburning process. Computer simulations for coal: LB blends were performed by modifying an existing computer code to include the drying and phosphorus (P) oxidation models. The gasification studies revealed that there is bed agglomeration in the case of chicken litter biomass due to its higher alkaline oxide content in the ash. Finally, the results of the economic analysis show that considerable fuel cost savings can be achieved with the use of biomass. In the case of higher ash and moisture biomass, the fuel cost savings is reduced.

show abstract