Calcium magnesium acetate and urea advanced reburning for NO control with simultaneous SO2 reduction

Nimmo, W.; Patsias, A. A.; Hampartsoumian, E.; Gibbs, B.M.; Fairweather, M.; Williams, Paul T.

doi:10.1016/j.fuel.2003.11.011

Cited by 28 publications

(13 citation statements)

References 7 publications

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“…The de-NO x efficiency can be increased through the use of additional compounds, such as ammonia, urea or metals, that can be introduced simultaneously with the main reburning fuel. This modification is known in the literature as advanced reburning [9][10][11]. An application of ammonia can be risky because of ammonia slip, the build-up of ammonium salts on heat-transfer surfaces and the creation of ammonium chloride [1]; consequently, metallic iron has been proposed as an alternative additive in advanced reburning [9].…”

Section: Introductionmentioning

confidence: 99%

Investigations of the reduction of NO to N2 by reaction with Fe under fuel-rich and oxidative atmosphere

Lasek

2014

Heat Mass Transfer

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The limitation of nitrogen oxides (NO x ) emissions from stationary combustion chambers is still an important issue in the field of the natural environment protection. This paper describes the reduction of NO x in the presence of iron. A few new aspects of research describing the utilization of iron as an additive that influences NO x reduction at high temperatures are presented. In particular, the influence of the excess air number (k) on the NO x removal efficiency in the presence of Armco iron was determined. A [50 % increase in the efficiency was achieved at k = 0.6. The research was conducted using N 2 / NO mixed with a flue gas from carbon monoxide combustion. In addition, a correction factor (Arrhenius-type empirical equation) was determined, which enabled the calculation of the oxygen influence on the inhibition of the de-NO x reaction in the presence of iron. The NO x reduction was also tested using bearing steel samples. Finally, the use of iron in de-NO x processes under different combustion conditions is briefly reviewed and analyzed.

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Section: Introductionmentioning

confidence: 99%

Investigations of the reduction of NO to N2 by reaction with Fe under fuel-rich and oxidative atmosphere

Lasek

2014

Heat Mass Transfer

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“…The first stage involved the evaporation of a carboxylic radical, namely pentanone, in the lower temperature zone, yielding intermediate products CH i and CO [6,24], which could transform NO into N 2 . As shown in Figure 3(b), CP was fractured and the residual sorbent became loose after the evaporation of the pentanone, which is clearly shown by comparison with the sample before evaporation of pentanone (Figure 3(a)).…”

Section: Cp and CC Thermal Decomposition Characteristicsmentioning

confidence: 99%

Kinetic calculations for the thermal decomposition of calcium propionate under non-isothermal conditions

Niu

Han

2011

Chin. Sci. Bull.

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Calcium propionate (CP) is shown to be useful for simultaneous SO 2 /NO reduction in coal-fired power plants and its thermal decomposition characteristics are measured by thermogravimetric analysis in a feasibility study into more complete reduction of these hazardous gases. Calcium carbonate (CC), which has been used primarily for in-furnace desulfuration, was used for comparison. The thermal decomposition of this organic calcium-based sorbent began at low temperature, i.e. the carboxylic radical was evaporated from 565 K to 759 K for CP and the corresponding mass loss percentage was 47.79%. The residual was subsequently decomposed to release carbon dioxide between 843 K and 1012 K. The latter phase of the process occurred more readily than with CC because of the loose structure of CP resulting from evaporation of the carboxylic radical in the low temperature zone, which could be seen directly by scanning electron microscope. The maximum mass loss rates of this phase occurred at temperatures of 972 K and 1012 K for CP and CC, respectively. The Ozawa-Flynn-Wall method was used to calculate the activation energy during the thermal decomposition process at heating rates of 5, 7.5, 10 and 15 K/min. The result further confirmed the multistage characteristic of CP thermal decomposition, which could be seen in differential thermogravimetry curves. The reaction orders of CP in the conversion range 20%−80%, calculated using the Avrami theory were from 0.061 to 0.608, smaller than those of CC, which were 1.647 to 2.084. Sulfur dioxide (SO 2 ) and nitric oxide (NO) emitted from coal-fired power plants cause serious environmental problems and therefore many technologies for the reduction of these two hazardous gases have been explored [1,2]. Among these technologies, the wet-spray of organic calcium-based sorbents has the potential for simultaneous SO 2 and NO abatement. Calcium-based sorbents [3,4], such as calcium magnesium acetate (CMA), calcium acetate (CA), calcium formate (CF), calcium benzoate (CB) and calcium propionate (CP), can produce hydrocarbon fragments (CH i ) and Ca-based compounds during pyrolysis and so can combine the reburning process for NO reduction and impregnation of Ca-based compounds into the furnace for SO 2 capture. Thus, *Corresponding author (email: cml@sdu.edu.cn) investment and the running costs could be significantly reduced if this technology could be extended to coal fired power plants. conducted laboratoryscale experiments with a down-fired pulverized coal combustor operated at 80 kW to investigate the performance of the above organic sorbents for control of air-pollutant gases under a number of conditions, obtaining satisfactory results. CMA and CP have been used as the deicing agent and food preservative, respectively, and the recent researches showed these compounds could reduce both SO 2 and NO. Increasing interest is being shown in these environment-friendly calcium salts. They achieved 70%-80% NO and SO 2 reduction efficiencies using wet-spray injection at a calcium-to-sulfur m...

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“…The use of sulphureous fuel in boiler-houses leads to large amounts of sulphur dioxide emitted into the atmosphere (Nimmo et al 2004). It is well known that SO 2 easily oxidizes up to SO 3 in the presence of oxygen, and a catalyst for this reaction is nitrogen oxide.…”

Section: Carbamide Reactions With Sulphur (Vi) Oxidementioning

confidence: 99%

Thermodynamic Assessment of Carbamide Use for Reducing Boiler Nox, Co Flue Gas Emissions/Termodinaminis Katilinių Išmetamųjų Dujų Nox Ir Co Taršos Kenksmingumo Šalinimo Naudojant Karbamidą Įvertinimas/ Термодинамическая Оценка При Деконтаминации Эмиссии Nox И Co Выхлопных Газов Котельных Путем Использования Карбамида

Stepanonyte¹,

Blynas

2008

Journal of Environmental Engineering and Landscape Management

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Abstract. Some aspects of boiler toxic pollutant emission reduction in the presence of carbamide are discussed in the paper. Theoretical pollution reduction investigation was conducted by using thermodynamic function calculation methods and evaluating the Gibbs' energy value changes at various temperatures. The equations of these changes were derived. It was determined that the most reliable compounds, formed during the reaction between carbamide and nitrogen oxides, are CO 2 , nitrogen and water. Other products are formed when carbamide is oxidized. Also, it was found that carbamide could reduce sulphur oxides to sulphur, and in some cases -to H 2 S. The pyrolysis of carbamide is possible at temperatures above 450 K.

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Calcium magnesium acetate and urea advanced reburning for NO control with simultaneous SO2 reduction

Cited by 28 publications

References 7 publications

Investigations of the reduction of NO to N2 by reaction with Fe under fuel-rich and oxidative atmosphere

Investigations of the reduction of NO to N2 by reaction with Fe under fuel-rich and oxidative atmosphere

Kinetic calculations for the thermal decomposition of calcium propionate under non-isothermal conditions

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