Development of SNCR Technology and Prospects of Its Application

Anichkov, S. N.; Zykov, A. M.; Тумановский, А. Г.; Kulish, O. N.; Zaporozhskii, K. I.

doi:10.1134/s004060152106001x

Cited by 9 publications

(5 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The main disadvantages of SNCR are the ammonia slip, that there should be little or no hydrocarbons or CO present, and the narrow temperature range (900−1050 °C when using urea) for its maximum efficiency. 9 In SCR, the ammonia is chemisorbed on a catalyst and reacts with NO or NO 2 from the gas phase, enabling operation at lower temperatures, usually between 250 and 400 °C, 11 but the SCR technique is limited due to poisoning of the catalyst, particularly, in flue gases containing high amounts of fly ash or dust.…”

Section: Introductionmentioning

confidence: 99%

“…NO x emissions resulting from thermal conversion of solid and liquid fuels, and also from other industrial processes, continue to be a major challenge for environmental reasons and due to increasingly strict emission limits. In the last 50 years, numerous studies investigated the formation and chemistry of NO x emissions experimentally, computationally, and at an industrial scale. − NO x emissions can be reduced by selective noncatalytic reduction (SNCR) − and selective catalytic reduction (SCR). , In the SNCR process, NO and NO 2 are reduced to N 2 by injecting ammonia (NH 3 ) or urea (CO(NH 2 ) 2 ) in the presence of oxygen. The main disadvantages of SNCR are the ammonia slip, that there should be little or no hydrocarbons or CO present, and the narrow temperature range (900–1050 °C when using urea) for its maximum efficiency .…”

Section: Introductionmentioning

confidence: 99%

“…In the last 50 years, numerous studies investigated the formation and chemistry of NO x emissions experimentally, computationally, and at an industrial scale. − NO x emissions can be reduced by selective noncatalytic reduction (SNCR) − and selective catalytic reduction (SCR). , In the SNCR process, NO and NO 2 are reduced to N 2 by injecting ammonia (NH 3 ) or urea (CO(NH 2 ) 2 ) in the presence of oxygen. The main disadvantages of SNCR are the ammonia slip, that there should be little or no hydrocarbons or CO present, and the narrow temperature range (900–1050 °C when using urea) for its maximum efficiency . In SCR, the ammonia is chemisorbed on a catalyst and reacts with NO or NO 2 from the gas phase, enabling operation at lower temperatures, usually between 250 and 400 °C, but the SCR technique is limited due to poisoning of the catalyst, particularly, in flue gases containing high amounts of fly ash or dust.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Role of Sulfite Oxidation in NO₂ Absorption in a pH-Neutral Scrubber Solution

et al. 2022

View full text Add to dashboard Cite

Nitrogen dioxide (NO2) absorption in aqueous sulfite solutions has recently gained more attention to reduce NO x emissions. The NO2 removal efficiency is strongly influenced by the competing reactions of NO2 absorption and sulfite oxidation. The present study investigates the role of sulfite oxidation in NO2 absorption at neutral pH. The effects of sulfite concentration, thiosulfate, pH, NO2 inlet concentration, oxygen concentration on NO2 absorption efficiency, and sulfite oxidation rates were investigated under well-controlled conditions at 25 °C in a laboratory-scale wet scrubbing system. NO2 absorption rates showed a strong dependence on the sulfite concentration and increased linearly with increasing NO2 inlet concentrations between 25 and 150 ppm. At the highest investigated sulfite concentration, 20 mM, the NO2 removal efficiency was around 80%. Oxidation rates of sulfite during NO2 absorption in the presence of 5 vol % O2 increased with increasing sulfite concentrations in the scrubbing solution and ranged from 20 mg·L–1·min–1 with 1 mM sulfite to 200 mg·L–1·min–1 with 20 mM sulfite. The oxidation rate decreased significantly when thiosulfate was added, while the oxidation rates were independent of the oxygen concentration between 2–10 vol % O2. The NO2 absorption rate decreased with decreasing pH between pH 6 and 8 proportionally to the sulfite concentration as predicted by the sulfite–bisulfite equilibrium. The implication from these results is that significantly less sulfite feeding is needed in industrial NO2 absorption if the pH can be maintained at neutral pH, instead of lower pH such as in simultaneous SO2 and NO2 scrubbing.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Role of Sulfite Oxidation in NO₂ Absorption in a pH-Neutral Scrubber Solution

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Since Lyon invented the SNCR technology for NO removal in 1975, this technology, which uses reducing agents without catalysts to reduce nitrogen oxides at specific flue gas temperatures, has been a highly costeffective approach. The advantages of applying SNCR in coal powder boilers are mature technology, small system footprint, low investment cost, short construction period, and small impact on boiler operation [3] , In garbage incinerators, power generation efficiency can also be improved [4] . The disadvantage is that the denitrification efficiency decreases with the increase of furnace size, and the efficiency is not high in practical applications [5] .…”

Section: Introductionmentioning

confidence: 99%

Denitration Simulation of SNCR System Nozzles at Different Layout Positions in Coal Powder Boilers

Li,

Cheng,

et al. 2024

E3S Web Conf.

View full text Add to dashboard Cite

Building a clean, low-carbon, safe and efficient energy system is an overall requirement for the modernization of the energy system, The nitrogen oxides produced by the combustion of fossil fuels need to be effectively treated. The selective non-catalytic reduction denitrification (SNCR) technology in the thermal power industry. It is widely used due to its low cost and mature technology. By using CFD software to simulate and study the coupling of flue gas temperature field and NO concentration field, the SNCR nozzle was set up to study the impact on denitrification efficiency. Simulate multiple layout methods, including sequential arrangement, staggered arrangement, concentrated in the middle and concentrated on both sides. The denitrification efficiency is highest among them, which is concentrated on both sides and further optimized through the NO concentration field in the furnace. After optimization, the denitrification efficiency reached 59.2%, which was 2.4% higher than the traditional uniform layout method. It has important practical guidance significance for energy conservation, emission reduction, and operational optimization.

show abstract

“…However, due to the low volatility and poor reactivity of anthracite, it inevitably suffers from the difficulties of ignition and burn-out [ 2 ], resulting in severe environmental problems such as photochemical smog, acid rain, forest deterioration, and ozone depletion [ 3 ]. Owing to the strict standards for NOx emissions in China (decreased below 50 mg/m 3 at 6% O 2 ) [ 4 ], numerous researchers have made great efforts to lower NOx emissions, including through selective catalytic reduction (SCR) [ 5 ], selective non-catalytic reduction (SNCR) [ 6 ], low-NOx burners [ 7 ], and air/fuel staged combustion technology [ 8 ]. However, these methods have inevitably exhibited limitations such as catalyst pollution, ammonia leaking, and high operational cost.…”

Section: Introductionmentioning

confidence: 99%

Experimental and DFT Research on the Effects of O2/CO2 and O2/H2O Pretreatments on the Combustion Characteristics of Char

Zhang

Sun

et al. 2023

Molecules

View full text Add to dashboard Cite

The use of a coal-based energy structure generates a large amount of CO2 and NOx. The numerous emissions from these agents result in acid rain, photochemical smog, and haze. This environmental problem is considered one of the greatest challenges facing humankind in this century. Preheating combustion technology is considered an essential method for lowering the emissions of CO2 and NO. In this research, the char prepared from O2/CO2 and O2/H2O atmospheres was employed to reveal the effects of the addition of an oxidizing agent on the combustion characteristics of char. The structural features and combustion characteristics of preheated chars were determined by Raman, temperature-programmed desorption (TPD), and non-isothermal, thermo-gravimetric (TGA) experiments. According to the experimental results, the addition of oxidizing agents promoted the generation of smaller aromatic ring structures and oxygen-containing functional groups. The improvement in the surface physicochemical properties enhanced the reactivity of char and lowered its combustion activation energy. Furthermore, the combustion mechanisms of the char prepared from the O2/CO2 and O2/H2O atmospheres were investigated using the density functional theory (DFT). The simulation results illustrated that the combustion essence of char could be attributed to the migration of active atoms, the fracture of the benzene ring structure, and the reorganization of new systems. The addition of oxidizing agents weakened the conjugated components of the aromatic ring systems, promoting the successive decomposition of CO and NO. The results of this study can provide a theoretical basis for regulating the reaction atmosphere in the preheating process and promoting the development of clean combustion for high-rank coals.

show abstract

Development of SNCR Technology and Prospects of Its Application

Cited by 9 publications

References 4 publications

Role of Sulfite Oxidation in NO₂ Absorption in a pH-Neutral Scrubber Solution

Role of Sulfite Oxidation in NO₂ Absorption in a pH-Neutral Scrubber Solution

Denitration Simulation of SNCR System Nozzles at Different Layout Positions in Coal Powder Boilers

Experimental and DFT Research on the Effects of O2/CO2 and O2/H2O Pretreatments on the Combustion Characteristics of Char

Contact Info

Product

Resources

About

Development of SNCR Technology and Prospects of Its Application

Cited by 9 publications

References 4 publications

Role of Sulfite Oxidation in NO2 Absorption in a pH-Neutral Scrubber Solution

Role of Sulfite Oxidation in NO2 Absorption in a pH-Neutral Scrubber Solution

Denitration Simulation of SNCR System Nozzles at Different Layout Positions in Coal Powder Boilers

Experimental and DFT Research on the Effects of O2/CO2 and O2/H2O Pretreatments on the Combustion Characteristics of Char

Contact Info

Product

Resources

About

Role of Sulfite Oxidation in NO₂ Absorption in a pH-Neutral Scrubber Solution

Role of Sulfite Oxidation in NO₂ Absorption in a pH-Neutral Scrubber Solution