Reburning mechanisms in A pulverized coal combustor

Mereb, J.B.; Wendt, Jost O.L.

doi:10.1016/s0082-0784(06)80390-5

Cited by 24 publications

(17 citation statements)

References 5 publications

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“…However, high reburning fuel fraction may result in high unburned carbon ratio, corrosion at inner furnace wall and low ash melting point. This finding is new and different from that of Mereb and Wendt [28] and Overmoe [29]. The former team reveals in their report that the optimum NO reduction efficiency is achieved at RF22 under SR1 = 1.0.…”

Section: Effect Of Reburning Fuel Fractionscontrasting

confidence: 69%

Parametric study of reburning of nitrogen oxide for superfine pulverized coal

Shen

Liu

et al. 2015

Energy Conversion and Management

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Section: Effect Of Reburning Fuel Fractionscontrasting

confidence: 69%

Parametric study of reburning of nitrogen oxide for superfine pulverized coal

Shen

Liu

et al. 2015

Energy Conversion and Management

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“…This assumption required the inclusion of Reaction 41 (NO + NH) as an N2 forming reaction .in the overall mechanism. The assumption of steady state for N20 concentration was not made in the early stages of development of the model (Mereb and Wendt, 1990) and better predictions were obtained for both NO and NH3, as seen in Figure 7.13. Ali the natural gas reburning data of Figure 7.13 correspond to initial temperatures that were below 1500 K in the reburn zone.…”

Section: Evaluation Of the Kinetic Modelmentioning

confidence: 99%

Nitrogen oxide abatement by distributed fuel addition. Final report

Wendt¹,

Mereb²

1991

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Reburning is examined as a means of NOx destruction in a 17 kW down-fired pulverized coal combustor. In reburning, a secondary fuel is introduced downstream of the. primary flame to produce a reducing zone, favorable td NO destruction, and air is introduced further downstream to complete the combustion. Emphasis is on natural gas reburning and a bituminous coal primary flame. A parametric examination of reburning • employing a statistical experimental design, is conducted, complemented by detailed experiments. Mechanisms governing the inter-conversion of nitrogenous species in the fuel rich reburn zone are explored. The effect of reburning on N20 emissions, the effect of primary flame mode (premixed and diffusion) and the effect of distributing the reburning fuel, are also investigated. The parametric study allowed the effects of significant reburning variables to be identified and examined, but these effects could not be quantified. Detailed experiments identified optimum reburn zone stoichiometry between 0.8 and 0.9, depending on mixing in the reburn zone. Overall NO reductions, as high as 80%, were possible and depended mainly on reburn zone variables, namely, temperature, residence time and stoichiometry. ,I Exhaust N20 emissions increased after air addition in the final stage of reburning, but were less than 10 ppm. Lower reductions in NO emissions were obtained when the primary flame was of the diffusion type, rather than of the prernixed type, but final NO emissions below 250 ppm (dry, 0% O2) were still possible. Reburning fuel introduction in multiple streams did not enhance NO destruction, relative to single stream injections. Within the reburn zone, rebuming mechanisms ocbarred in two regimes. One regime was in the vicinity of the rebuming fuel flame and was distinguished by fast reactions between NO and hydrocarbons that were limited by mixing. The other regime covered the remainder of the reburn zone and was distinguished by slower reactions, without mixing complications. For the latter regime, a simplified model based on detailed gas phase chemical kinetic mechanisms .and known rate coefficiems was able to predict temporal profiles of NO, HCN and NII 3. Reactions involving hydrocarbons played important roles in both regimes and N2 fixation by hydrocarbons limited reburning effectiveness at low primary NO values. Appropriate corrections for mixing effects in early time scales of the reburn zone allowed the prediction of nitrogenous species profiles from primary NO values, as well as overall reburning effectiveness.

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“…Take the temperature of each nozzle working medium as equal, the fllowing formula can be obtained using formula (1) and (2):…”

Section: The Experiments Principlementioning

confidence: 99%

“…Natur al gas reburning technology is a promising method for denitrification [1], In recent years, study on mechanism of reduce NOx with natural gas reburning in many countries found that compounds containing nitrogen HCN in reburning fuel has important influence on the reburning process. Patry and Engel [2] think that the product of reactions for nitrogen oxide and methane is HCN、water and hydrogen after study, also found that about 70% of the NOx has been transformed in a short time .…”

Section: Introductionmentioning

confidence: 99%

Cold-state Experimental Study on Flow Characteristics of Multi-nozzle in Natural Gas Reburning Burner

Chen¹,

Zhang²,

Bi³

2013

EPE

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Based on the prototypes of a 130 t/h boiler, constant proportional cold-state test bench is established, flow characteristics of multi-nozzle in natural gas reburning burner and its influence on the covering effect for the upflow in the furnace are researched. Numerical simulations of this process are also made with standard k   turbulence model. The results show that air flow fullness in furnace is better in the case of the reburning zone with 8 nozzles compared to 4 nozzles and also coverage effect of the reburning flow for the updraft gas in the furnace is better. In the condition each nozzle airflow velocity is constant, the effect of reburning flow on coverage of up-secondary air is best when the incident angle for four corners is 14.17˚, while Center of the furnace wall is 84.57. And while the best incident angle is invariable, the effect of reburning flow on coverage of up-secondary air is best when the speed of reburning gas in the corners of furnace is 51 m/s, the same to the center of the furnace wall's.

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Reburning mechanisms in A pulverized coal combustor

Cited by 24 publications

References 5 publications

Parametric study of reburning of nitrogen oxide for superfine pulverized coal

Parametric study of reburning of nitrogen oxide for superfine pulverized coal

Nitrogen oxide abatement by distributed fuel addition. Final report

Cold-state Experimental Study on Flow Characteristics of Multi-nozzle in Natural Gas Reburning Burner

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