NOx and CO2 emissions for 1,132 turbofan commercial engines ranging between 9.79 and 581. 23 kN plot

ICAO Aircraft Engine Emission Databank (EEDB), 2021

Aircraft engine CO2 & NOX emissions

NOx and CO2 emissions for 1,132 turbofan commercial engines ranging between 9.79 and 581. 23 kN plotted over a normal probability distribution function.

Pedro Baldó July 2022

Turbojet and turbofan engines Engine technology has continuously evolved over the last 70 years, and reduction in fuel burn has always been a driving force behind this progress. More fuel efficient engine cycles, often made possible through the use of new materials, has led to increasing pressures and temperature within the combustor. Since this tends to increase the emissions of nitrogen oxides (NOX), the control of these emissions through the combustor design is a significant challenge. The ICAO regulatory limits for engine NOX emissions has been gradually tightened over time, and are usually referred to by the corresponding CAEP meeting number (CAEP/2, CAEP/4, CAEP/6 and CAEP/8). The engine NOX standard, and the new aircraft CO2 standard, contribute in defining the design space for new products so as to address both air quality and climate change issues. The regulatory NOX limits are defined as the mass (Dp) of NOx/CO2 emitted during the Landing and TakeOff (LTO) test cycle and divided by the thrust of the engine (F00). The limit also depends on the overall pressure ratio of the engine. The current ICAO technology goals for NOX are also shown. These goals, which were agreed in 2007, represent the expected performance of expected ‘leading edge’ technology in 2016 (midterm) and 2026 (long term).

NOx and CO2 emissions for 1,132 turbofan commercial engines ranging between 9.79 (2,200) and 581.23 (130,660) kN (lbsf) plotted over a normal probability distribution function ICAO Engine Standards and Emission Database 2021 To control pollutants from aircraft, ICAO established emissions measurement procedures and compliance standards for NOx / CO2, soot, (measured as smoke number-SN) and unburned hydrocarbons. The standards are applied to all newly manufactured turbojet and turbofan engines that exceed 9.79 kN rated thrust output at International Standard Atmosphere (ISA) sea level static (SLS) conditions.

The smoke standards took effect in 1983, and those for gaseous emissions took effect in 1986. Measurements of the exhaust emissions of a single engine are performed at the manufacturer's test facilities as part of the certification process in compliance with the requirements of ICAO international standards and Annex 16 to the convention on international aviation (ICAO, 1993).

The data are published in an ICAO exhaust emissions data bank (ICAO 1995).

Together with fuel flow, emission indices of HC, CO, and NOx in gr. / kN and

This study set its emphasis on trying to quantify pollutant concentrations released to the atmosphere, NOx and CO2, particularly those emitted between 3,000 ft & 51,000 ft (upper atmosphere, lower troposphere), which is the upper range for some Executive Liners and LR Mid-Size Turbofans. Since data is NOT AVAILABLE for transatlantic flights and LR, HH deployments of these powerplants, models had to be relied upon. Data might be taken at its most approximate value, as that which has been provided by the models (when not enough supporting data could be found from ICAO & EASA). Comparison of all available in situ measured NOx, CO2 (average) emission index values with corresponding predicted values were consistently checked against each other before being used in the final plots.

There has not been sufficient characterization to date for global inventory purposes, with most of the available data acquired from a selection of engines using kerosene-type fuel with different specifications. Additionally, nitrous oxides (N2O) have not been rigorously characterized. Other emissions are not currently modeled in emissions´ databases because of the small quantity of it available or the fact that little data exists.

This report hopes to level the missing data deficit with particular focus on NOx and CO2 emissions deriving from for commercial subsonic power plants available in the market with mean power thrust of 152.65 kN & a standard deviation of 142.86 kN, considered from μ-1σ up to μ+3σ, and with range of inlet temperatures to the hp turbine μ = 864.35 C , σ = 170.03 C, considered from μ-1σ up to μ+4σ.

https://lnkd.in/eTuxkYUp https://lnkd.in/e6YBEXyN https://lnkd.in/e_hxTZjx https://archive.ipcc.ch/ipccreports/sres/aviation/107.htm https://www.easa.europa.eu/eaer/topics/technology-and-design/aircraft-engineemissions #nox #c02 #ghgemissions #power #aviation #compliance #database #hydrocarbons #military #ICAO #EASA

Final Remarks and Conclusions NOx is primarily formed through high temperature reaction between nitrogen and oxygen in the air. In contrast, CO2 is formed from a stoichiometric combustion of carbon or carbon compounds with air, or when carbonates or bicarbonates are treated with acids or decomposed by heating.

The sea is the great sink of CO2, acting as a huge buffer, letting it dissolve in or escape from it as required. But there is a limit.

From the ICAO data, we can conclude: The higher the NOx production of an engine, the higher the temperature at the inlet to the combustor (hp turbine stage). Usually CO2 production for the same engine will be lower, which makes definitive selection of a ¨clean engine¨ somewhat more of a challenge.

We can see that many engines out of production, such as the CFM56 5B9-2P, have very good compliance with mid-term goal alignments, even as of today.

Amazingly, many engines in production certified between 2008-2014, are way behind meeting CAEP/6, let alone CAEP /8 goals, as compared with engines in production certified between 1996-2007, such as the CFM56- 7B20E, all the way up to the Engine Alliance GP7270.

Some of these engines, such as the GEnX -1B54 and the Pure Energy family of engines, PW1521/ 1400X, PW 1124G-JM, PW 1127G-JM, are even approaching long term goals today and are even one step ahead of the newest Rolls Royce engines (RR Trent XWB – 79/84/97 & RR Trent 1000 – H3/AE3/G3/N3/P3/Q3/R3 , RR Trent 7000 – 72C) certified from 2015 onwards (new certification) with OPRs of up to 49.4 and Dp/ Foo´s (gr./kN) 76.3.

The two standard probability distribution plots that are presented, show the marked trend of aircraft engines to continuously move towards a cleaner milestone. The area encompassing the plots cover at least 83.4 % of all commercial aircraft power plants in the market today, many of which have not been named for clarity, but have nevertheless been included in the plots. The wide gap in missing data can be gauged from a large std. dev.