Minimum environmental load extension through compressed air extraction: Numerical analysis of a dry low NOx combustor

Gas turbines that are used as compressor drives are often operated in the part load regime because compressor stations are usually designed for operation with full power at extreme weather conditions. Consequently, these gas turbines must comply with strict emission regulations at unfavorably low turbine inlet temperatures. To extend the low emissions operation range of the premixed combustion systems, many gas turbines bypass a part of the compressed air upstream of the combustor and either blow it off into the exhaust stack or re-inject it into the secondary combustion zone. This study presents a new approach that overcomes shortcomings by injecting the compressed air in the burner head in the vicinity of the primary combustion zone. This is particularly attractive for multi can combustors. Atmospheric combustion tests are conducted for two different air injection designs. The first design features lower air injection velocity and the second features higher injection velocities. Both injection strategies are tested with the industrial MGT gas turbine can combustor. The full size burner is tested at atmospheric conditions in a burner test rig with a quartz flame tube and natural gas as fuel. The performance of the air bypass system is assessed by means of CO and NOx emission measurements for different air bypass ratios. Additionally, OH* chemiluminescence camera pictures are presented and compared to CFD calculations. It is found that the air injection in the annular vicinity of the swirl flame does not cause increased CO emissions by quenching or other effects.

show abstract

Assessment of a staged and inclined hopper-air injection in enhancing low-NO_x combustion and establishing a safe hopper environment for a large-scale arch-fired furnace

Cheng,

Kuang,

Zhao

2024

Energy & Environment

View full text Add to dashboard Cite

In response to the high NO x emissions and hopper overheating problem of a 600-MWe arch-fired furnace, a staged arch-firing framework (SAF) with an upper/lower staged hopper-air pattern was proposed to replace the original low-NO x technique. With implementing such a staged hopper-air configuration to enhance air staging and reduce the downward flame penetration, it was required to (i) affirm the SAF's effectiveness related to the mentioned problems and (ii) assess the upper hopper-air (UHA) angle effect for obtaining a reasonable UHA angle. Accordingly, the in-furnace flow, combustion, and NO x generation were respectively investigated under five UHA angles of θ = 0°, 20°, 30°, 35°, and 40°. Meanwhile, real-furnace tests and simulations in the original furnace were conducted to make comparisons with the SAF furnace. As θ increased, the flame penetration progressively deepened. The primary hopper-air function in favoring char combustion and overall combustion performance first strengthened and then weakened, while the production of CO and NO and combustible matter in fly ash first dropped and then ascended. The setup with θ = 35° demonstrated the most favorable low-NO x performance, exhibiting NO x levels of about 600 mg/m3 (O2 = 6%) and combustible matter of about 5% in fly ash. A comparison before and after the SAF application indicates that, despite reducing downward flame penetration, the SAF bolstered primary combustion and increased air utilization to facilitate char combustion in the hopper and the burnout zone. Consequently, a further 33.5% NO x reduction was achieved, along with slight burnout improvement and notably reduced hopper temperatures.

show abstract

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

customersupport@researchsolutions.com

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Minimum environmental load extension through compressed air extraction: Numerical analysis of a dry low NOx combustor

Cited by 3 publications

References 28 publications

Synergetic performance of gas turbine combined cycle unit with inlet cooled by quasi-isobaric ACAES exhaust

Synergetic performance of gas turbine combined cycle unit with inlet cooled by quasi-isobaric ACAES exhaust

Innovative Air Bypass System for Low-Emission Multi-Can Combustors

Assessment of a staged and inclined hopper-air injection in enhancing low-NO_x combustion and establishing a safe hopper environment for a large-scale arch-fired furnace

Contact Info

Product

Resources

About

Minimum environmental load extension through compressed air extraction: Numerical analysis of a dry low NOx combustor

Cited by 3 publications

References 28 publications

Synergetic performance of gas turbine combined cycle unit with inlet cooled by quasi-isobaric ACAES exhaust

Synergetic performance of gas turbine combined cycle unit with inlet cooled by quasi-isobaric ACAES exhaust

Innovative Air Bypass System for Low-Emission Multi-Can Combustors

Assessment of a staged and inclined hopper-air injection in enhancing low-NOx combustion and establishing a safe hopper environment for a large-scale arch-fired furnace

Contact Info

Product

Resources

About

Assessment of a staged and inclined hopper-air injection in enhancing low-NO_x combustion and establishing a safe hopper environment for a large-scale arch-fired furnace