Control of NOx and other emissions in micro gas turbine combustors fuelled with mixtures of methane and ammonia

Okafor, Ekenechukwu C.; Somarathne, Kapuruge Don Kunkuma Amila; Ratthanan, Rattanasupapornsak; Hayakawa, Akihiro; Kudo, Taku; Kurata, Osamu; Iki, Norihiko; Tsujimura, Taku; Furutani, Hirohide; Kobayashi, Haruo

doi:10.1016/j.combustflame.2019.10.012

Cited by 210 publications

(141 citation statements)

References 47 publications

Supporting

Mentioning

129

Contrasting

Order By: Relevance

“…Okafor et al [17] discovered that compared to ammonia non-premixed combustion, its counterpart premixed one tended to give a low NO x emission. In their follow-up work, experimental and numerical investigations on the emission performance of ammonia-methane-air in a micro gas turbine combustor were implemented [25]. It was found that the optimum equivalence ratio, where NO x emission was lower, was found to vary from 1.30 to 1.35 depending on the NH 3 concentration.…”

Section: Introductionmentioning

confidence: 99%

NO emission performance assessment on a perforated plate-implemented premixed ammonia-oxygen micro-combustion system

Cai

Becker

Cao

et al. 2021

Chemical Engineering Journal

View full text Add to dashboard Cite

The present work examines the NO x emission characteristics of a premixed micro-combustion system with a perforated plate implemented. For this, a three-dimensional (3D) computational model involving a detailed chemical-kinetic mechanism for ammonia-oxygen combustion in the micro-combustor is developed. The model is first validated with the experimental measurements available in the literature before conducting comprehensive analyses. It is found that implementing a perforated plate in the micro-combustion system creates a flow recirculation zone downstream characterized by a low flame temperature and combustion speed. Meanwhile, the conjugate heat transfer between the combustion products and the inner combustor walls is shown to play a key role in the NO generation by relocating the flame in the axial direction and thus changing the chemical reaction rate. Furthermore, the preferential diffusion caused by the variation in the mass diffusivity of different species and the two-dimensionality flow is identified to vary significantly in comparison with the case in the absence of the perforated plate, especially in the vicinity of the recirculation zone. This diffusion effect results in the considerable drop in the N/O atomic ratio, primarily due to the reduction and increase of O 2 and H 2 O, together with less available N 2 , and consequently affecting the NO generation rate. This work confirms that the flow field, the conjugate heat transfer as well as the preferential diffusion effect could be regarded as the potential mechanisms leading to the NO x emission variation in the recirculation zones. Nomenclature 3Dthree-dimensional specific heat of species, CO carbon monoxide CO 2 carbon dioxide CH 4

show abstract

Section: Introductionmentioning

confidence: 99%

NO emission performance assessment on a perforated plate-implemented premixed ammonia-oxygen micro-combustion system

Cai

Becker

Cao

et al. 2021

Chemical Engineering Journal

View full text Add to dashboard Cite

show abstract

“…In theory, combustion of ammonia should result in the emission of only nitrogen and water. Imperfect combustion, however, results in the emission of nitrogen oxides (NO x ) (Okafor et al, 2020). The possibility of influencing NO x emissions by controlling the equivalence ratio (Sun et al, 2021) and by the addition of water (Ariemma et al, 2020) has been explored.…”

Section: Introductionmentioning

confidence: 99%

A Comparative Environmental Life Cycle Assessment of the Combustion of Ammonia/Methane Fuels in a Tangential Swirl Burner

Razón

Valera‐Medina

2021

Front. Chem. Eng.

View full text Add to dashboard Cite

Ammonia has been proposed as a replacement for fossil fuels. Like hydrogen, emissions from the combustion of ammonia are carbon-free. Unlike hydrogen, ammonia is more energy dense, less explosive, and there exists extensive experience in its distribution. However, ammonia has a low flame speed and combustion emits nitrogen oxides. Ammonia is produced via the Haber-Bosch process which consumes large amounts of fossil fuels and requires high temperatures and pressures. A life cycle assessment to determine potential environmental advantages and disadvantages of using ammonia is necessary. In this work, emissions data from experiments with generating heat from tangential swirl burners using ammonia cofired with methane employing currently available technologies were utilized to estimate the environmental impacts that may be expected. Seven ammonia sources were combined with two methane sources to create 14 scenarios. The impacts from these 14 scenarios were compared to those expected from using pure methane. The results show that using ammonia from present-day commercial production methods will result in worse global warming potentials than using methane to generate the same amount of heat. Only two scenarios, methane from biogas combined with ammonia from hydrogen from electricity and nuclear power via electrolysis and subsequent ammonia synthesis using nitrogen from the air, showed reductions in global warming potential. Subsequent analysis of other environmental impacts for these two scenarios showed potentially lower impacts for respiratory organics, terrestrial acidification-nutrification and aquatic acidification depending on how the burner is operated. The other eight environmental impacts were worse than the methane scenario because of activities intrinsic to the generation of electricity via wind power and nuclear fission. The results show that generating heat from a tangential swirl burner using ammonia currently available technologies will not necessarily result in improved environmental benefits in all categories. Improvements in renewable energy technologies could change these results positively. Other means of producing ammonia and improved means of converting ammonia to energy must continue to be explored.

show abstract

“…Each gas turbine unit consists of a compressor for compressing air, a combustion chamber for mixing air with fuel and combustion, and a turbine for converting hot and compressed gas energy into mechanical energy [7]- [9]. Due to the increasing importance of gas turbines in various industries and the necessity of designing the proper control system for gas turbines as the beating heart of this industry, extensive research has been done in the recent years [10]- [13].…”

Section: Introductionmentioning

confidence: 99%

Gas Turbines Power Regulation Subject to Actuator Constraints, Disturbances and Measurement Noises

et al. 2021

View full text Add to dashboard Cite

An accurate understanding of the output power functionality in gas turbines concerning the fuel, inlet valve status and other parameters can provide a general overview of the turbine's performance. In this study, the problem of practical power regulation in gas turbines is investigated in the simultaneous presence of actuator constraints, unknown disturbances, and measurement noises. To this aim, a model predictive controller-based approach is utilized because of its high flexibility combined with a twolayer filtering and anti-filtering procedure to efficiently cope with the measurement noises. Moreover, the proposed structure takes the effects of unknown disturbances into account and thereby it is shown that the proposed controller can efficiently achieve all design objectives while handling actuator constraints, disturbances and measurement noises.

show abstract

Control of NOx and other emissions in micro gas turbine combustors fuelled with mixtures of methane and ammonia

Cited by 210 publications

References 47 publications

NO emission performance assessment on a perforated plate-implemented premixed ammonia-oxygen micro-combustion system

NO emission performance assessment on a perforated plate-implemented premixed ammonia-oxygen micro-combustion system

A Comparative Environmental Life Cycle Assessment of the Combustion of Ammonia/Methane Fuels in a Tangential Swirl Burner

Gas Turbines Power Regulation Subject to Actuator Constraints, Disturbances and Measurement Noises

Contact Info

Product

Resources

About