Primary air ratio affects coal utilization mode and NOx emission in lignite pulverized boiler

Li, Zixiang; Miao, Zhengqing

doi:10.1016/j.energy.2019.116023

Cited by 30 publications

(7 citation statements)

References 49 publications

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“…In particular, when the SCA ratio increased from 20% to 90%, the level of NO emissions decreased from 69.43 to 43.52 ppm, and the reduction rate was 37.3%. Jing et al [30] and Li and Miao [31] obtained qualitatively similar results even though their studies were conducted using pulverized coal-fired boilers. Near the burner, the NO x concentration decreased and the gas temperature increased, with a decreasing PCA ratio [30].…”

Section: X For Peer Review 8 Of 14mentioning

confidence: 66%

Section: X For Peer Review 8 Of 14mentioning

confidence: 99%

“…Near the burner, the NOx concentration decreased and the gas temperature increased, with a decreasing PCA ratio [30]. As the SCA ratio increased from 47% to 65%, the NO emission at the furnace exit decreased monotonously from 294 to 210 ppm [31]. Regarding the above NO reduction concept using burner air staging, the effects of the SCA ratio on the NO emission at the furnace exit and the temperature distribution of the furnace top-wall are presented Figure 6.…”

Section: X For Peer Review 8 Of 14mentioning

confidence: 99%

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Nitric Oxide Emission Reduction in Reheating Furnaces through Burner and Furnace Air-Staged Combustions

et al. 2021

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In this study, a series of experiments were conducted on a testing facility and a real-scale furnace, for analyzing the nitric oxide (NO) emission reduction. The effects of the temperature, oxygen concentration, and amount of secondary combustion air were investigated in a single-burner combustion system. Additionally, the NO-reduction rate before and after combustion modifications in both the burner and furnace air-staged combustion were evaluated for a real-scale reheating furnace. The air-to-fuel equivalence ratio (λ) of individual combustion zones for the furnace was optimized for NO reduction without any incomplete combustion. The results indicated that the NO emission for controlling the λ of a single-zone decreased linearly with a decrease in the λ values in the individual firing tests (top-heat, bottom-heat, and bottom-soak zones). Moreover, the multi-zone control of the λ values for individual combustion zones was optimized at 1.13 (top-preheat), 1.0 (bottom-preheat), 1.0 (top-heat), 0.97 (bottom-heat), 1.0 (top-soak), and 0.97 (bottom-soak). In this firing condition, the modifications reduced the NO emissions by approximately 23%, as indicated by a comparison of the data obtained before and after the modifications. Thus, the combined application of burner and furnace air-staged combustions facilitated NO-emission reduction.

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Section: X For Peer Review 8 Of 14mentioning

confidence: 66%

Section: X For Peer Review 8 Of 14mentioning

confidence: 99%

Section: X For Peer Review 8 Of 14mentioning

confidence: 99%

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Nitric Oxide Emission Reduction in Reheating Furnaces through Burner and Furnace Air-Staged Combustions

et al. 2021

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“…through a series of hydrogenation reactions under a high temperature and pressure environment facilitated by catalysts. In recent years, CTL has made great progress in the chemical industry, as well as in the combustion and reburning to reduce NOx (Xie et al, 2010;Li and Miao, 2019). Figure 1 shows a widely used CTL process for manufacturing liquid fuels in China.…”

Section: Introductionmentioning

confidence: 99%

Combined effect of coal chemical wastewater and PC on preparing of coal-to-liquids residue-based alkali activated materials

Zhu

et al. 2021

Journal of Hazardous Materials

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Aimed to achieve "waste control by waste" of coal-to-liquids (CTL) industry, coal gasification residue (CGR), the most typical CTL residue, and coal chemical wastewater (CCW) were used as aluminosilicate precursor and auxiliary activator respectively to prepare alkali activated materials (AAMs). CGR-based AAMs using a less concentrated NaOH solution than conventional, with CCW as mixing water were synthesized. The results showed that CCW benefited the compressive strength of CGR-based AAMs significantly, but demonstrating slight reduction over time. The combined effect of CCW and Portland cement (PC) supplied continuous increase of strength and eliminated the strength reduction with age. The mechanisms behind the improved performance of the AAMs due to the introduction of CCW and PC were discussed by XRD, FTIR, TG-DSC, MIP and ESEM. It was found that the increased alkali content due to the introduction of the CCW, supplied more extensive dissolution of active aluminosilicate and progressive geopolymerization of CGR. The coexistence of both N-A-S-H gel and C-A-S-H gel (originated from the introduced PC) in hardened AAM pastes reduced the proportion of pores larger than 100 nm to less than 30%, and provided denser structure.

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“…One of the main methods of suppressing "thermal" and "fuel" NOx is the step-by-step combustion of a pulverized coal mixture, including the "Overfire air" technology. The combustion consists in the fact that less air enters the main combustion area than is required at the theoretical level (α=0.70-0.95), and the remaining air supplied for the purpose of complete combustion of fuel is sent further at one or more levels along the height of the torch, resulting in a decrease in the maximum high temperature in the combustion area and the amount of O2 in the core of the torch is reduced, the reactions of NO formation are slowed down, and the length and luminosity of the torch also increase [7][8][9]. The distinctive principle of step-by-step combustion is the existence of a reduction zone in which, due to lack of air, incomplete combustion products are formed, and namely carbon monoxide and hydrogen, and nitrogen oxide is not formed at this time.…”

Section: Introductionmentioning

confidence: 99%

3D visualization of the results of using modern OFA technology on the example of real boiler

Jibril

2021

Preprint

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The leading place in the world for environmental protection is currently occupied by the protectionof the air basin. And the main sources of atmospheric pollution are industrial enterprises, motor transport andthermal power plants. Thus, there is an obvious need to increase attention to the problems of the innovationsector, mainly in the areas of technical improvement of heat and power industry enterprises. Therefore, thestudy of the problems of reducing the amount of harmful emissions into the atmosphere, control and regulationof its quality, as well as the study of new various methods of innovative development of thermal power is anurgent task at present, requiring a serious scientific approach. In the proposed work, computer experimentswere carried out in the field of innovative energy production technologies (the use of modern "sharp blast"OFA technology) at a specific thermal power facility of the enterprise of the Republic of Kazakhstan. Duringthe experiment, various ways of supplying additional air through OFA nozzles were investigated: OFA=0%(basic version without additional air supply), OFA=10% and OFA=18%. For these three modes, a comparativeanalysis of the aerodynamics of the furnace part of the boiler was performed according to the obtaineddistributions of the temperature and concentration fields of nitrogen oxide NO over the entire volume of thecombustion chamber. The results obtained were compared with experimental data obtained during experimentsconducted directly at the CHP.

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Primary air ratio affects coal utilization mode and NOx emission in lignite pulverized boiler

Cited by 30 publications

References 49 publications

Nitric Oxide Emission Reduction in Reheating Furnaces through Burner and Furnace Air-Staged Combustions

Nitric Oxide Emission Reduction in Reheating Furnaces through Burner and Furnace Air-Staged Combustions

Combined effect of coal chemical wastewater and PC on preparing of coal-to-liquids residue-based alkali activated materials

3D visualization of the results of using modern OFA technology on the example of real boiler

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