Fundamental Studies on NO and CO Emissions and their Control in Combustion Processes : 5th Report, Processes ahd Charactet1stics of NO Formation from Fuel Nitrogen

敏美, 高城; 利春, 巽; 光信, 小笠原; 高司, 辰己

doi:10.1299/kikai1938.44.4282

Cited by 10 publications

(4 citation statements)

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“…In this method the combustion is divided into two stages; in the first stage, fuel is burned with air in a rich premixed condition, and in the second stage, the remaining fuel is burned with secondary air. A variety of experimental studies [1][2][3][4] have been conducted on this method, mainly for development of large-scale furnaces and combustors, and it has been determined that the heat loss in the region behind the premixed flame of the first stage reduces the maximum temperature of the second stage flame, which suppresses the production of Zeldovich NO. Additionally, in the field of home combustion appliances, Umeda and co-workers recently developed a multiple-inner-port burner in which the NO x emission is considerably low [5].…”

Section: Introductionmentioning

confidence: 99%

NOx reduction mechanism of a methane–air Smithells flame

Nishioka

Ishigami

Horii

et al. 2006

Combustion and Flame

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Section: Introductionmentioning

confidence: 99%

NOx reduction mechanism of a methane–air Smithells flame

Nishioka

Ishigami

Horii

et al. 2006

Combustion and Flame

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“…Two-stage combustion with reducing flame (which has a primary combustion stage under fuel-rich conditions and a secondary stage in which remaining unburned fuel combusts completely), is widely accepted as a combustion technology for suppressing fuel-NOx production in conventional fuels [62,63,87]. It is also known that the fuel-NOx production mechanisms of conventional hydrocarbon fuels, such as CH 4 , are different from those of non-hydrocarbon fuels, such as CO and H 2 [88][89][90][91]. So gasified fuels consisted of CO and H 2 as the main combustible components contain thousands of ppm and a small percentage of CH 4 , and indicate a complex fuel-NOx production mechanism, while non-hydrocarbon fuels produce very few species of HCN.…”

Section: Supplied Fuels and Test Conditionsmentioning

confidence: 99%

“…If fuel contains CH 4 , HCN is produced by Reactions (5) and (6) in the fuel-rich region, and the HCN is oxidized to NO in the fuel-lean zone [89][90][91]117]. (27) With the rise in CH 4 constituent in the fuel, the HCN produced in the fuel-rich primary-combustion zone increases, and the NOx emissions originating from HCN in the fuel-lean secondary-combustion zone increase.…”

Section: Axial Distance MM Equivalence Ratiomentioning

confidence: 99%

Gas Turbine Combustion and Ammonia Removal Technology of Gasified Fuels

Hasegawa

2010

Energies

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From the viewpoints of securing a stable supply of energy and protecting our global environment in the future, the integrated gasification combined cycle (IGCC) power generation of various gasifying methods has been introduced in the world. Gasified fuels are chiefly characterized by the gasifying agents and the synthetic gas cleanup methods and can be divided into four types. The calorific value of the gasified fuel varies according to the gasifying agents and feedstocks of various resources, and ammonia originating from nitrogenous compounds in the feedstocks depends on the synthetic gas clean-up methods. In particular, air-blown gasified fuels provide low calorific fuel of 4 MJ/m 3 and it is necessary to stabilize combustion. In contrast, the flame temperature of oxygen-blown gasified fuel of medium calorie between approximately 9-13 MJ/m 3 is much higher, so control of thermal-NOx emissions is necessary. Moreover, to improve the thermal efficiency of IGCC, hot/dry type synthetic gas clean-up is needed. However, ammonia in the fuel is not removed and is supplied into the gas turbine where fuel-NOx is formed in the combustor. For these reasons, suitable combustion technology for each gasified fuel is important. This paper outlines combustion technologies and combustor designs of the high temperature gas turbine for various IGCCs. Additionally, this paper confirms that further decreases in fuel-NOx emissions can be achieved by removing ammonia from gasified fuels through the application of selective, non-catalytic denitration. From these basic considerations, the performance of specifically designed combustors for each IGCC proved the proposed methods to be sufficiently effective. The combustors were able to achieve strong results, decreasing thermal-NOx emissions to 10 ppm (corrected at 16% oxygen) or less, and fuel-NOx emissions by 60% or more, under conditions where ammonia concentration per fuel heating value in unit volume was 2.4 × 10 2 ppm/(MJ/m 3 ) or higher. Average equivalence ratio at combustor exhaust φ p Average equivalence ratio in primary combustion zone ΔP/q Total pressure loss coefficient (characteristic section is combustor-exit) OPEN ACCESS

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“…Two-stage combustion with reducing flame, which has a primary stage combustion under a fuel-rich condition and a secondary stage where the remaining unburned fuel combusts completely, is widely accepted as combustion technology to suppress the fuel-NOx production in conventional fuels (Martin and Dederick, 1977), (Yamagishi et al, 1974), (Pratt et al, 1971). It is also known that the fuel-NOx production mechanisms of conventional hydrocarbon fuels such as CH 4 are different from that of non-hydrocarbon fuels such as CO and H 2 (Fenimore, 1976), (Heap et al, 1976), (Takagi et al, 1978), (Kato et al, 1977). Because the non-hydrocarbon fuels hardly produce the species of HCN.…”

Section: Nox Emission Characteristics In Supplied-air Staging Combustionmentioning

confidence: 99%

Prediction Methodology of Fuel-NOx Emissions in Gasified Fuels’ Combustion

Hasegawa

2010

JGPP

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Gasification technologies enable conversion of low-grade resources to clean gases, and can generate electricity through gas turbine. However, gasified fuels contain nitrogenous compounds of NH 3 and HCN that cannot be removed in the case of employing a hot/dry-type synthetic gas cleanup for improvement of plant thermal efficiency and are oxidized into fuel-NOx in combustion processes. Fuel-NOx emissions constitute the majority of NOx emissions in exhaust. In combustion processes of the CO, H 2 and CH 4 mixture fuels, the oxidation characteristics of nitrogenous compounds are different from cases of conventional hydrocarbon fuels, and influenced by fuel constituents and combustion methods. Author had clarified influence of gasified fuel constituents on fuel-NOx emissions through experiment. This paper clarifies that conversion rate of nitrogenous compounds to fuel-NOx is decided by both a CH 4 concentration and primary equivalence ratio in the case of using two-stage combustion, while conversion rate is greatly affected by an H 2 constituent in the case of gasified fuel containing no CH 4. Consequently, a prediction methodology of conversion rate of fuel-N is established in the case of air-staging two-stage combustion.

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Fundamental Studies on NO and CO Emissions and their Control in Combustion Processes : 5th Report, Processes ahd Charactet1stics of NO Formation from Fuel Nitrogen

Cited by 10 publications

References 0 publications

NOx reduction mechanism of a methane–air Smithells flame

NOx reduction mechanism of a methane–air Smithells flame

Gas Turbine Combustion and Ammonia Removal Technology of Gasified Fuels

Prediction Methodology of Fuel-NOx Emissions in Gasified Fuels’ Combustion

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