gas engine air/fuel adjustment

8/12/2019 GAS ENGINE Air/Fuel Adjustment

http://slidepdf.com/reader/full/gas-engine-airfuel-adjustment 1/20



Emissions, What Are They?

Nitrogen Oxides (NOx)

Nitric Oxide (NO) & Nitrogen Dioxide (NO2)

Carbon Monoxide (CO)

Aldehydes

Hydrocarbon Recombinations, i.e. CH3OH

Particulates

Soot (Dry Carbon), Oil, Inorganics (Sulfur)



Emissions, What Are They?

Total Hydrocarbons (THC) or Unburned

Hydrocarbons (UHC)

Unburned Fuel CH4, C2H6, C3H8, …...

Also Known as: VOC Volatile Organic Compounds

ROC Reactive Organic Compounds

ROG Reactive Organic Gases



Emissions, Why Are They Bad?

Health Related Issues from Ingestion

Contribute to Acid Rain

Production of Ozone (O3)

Smog Creation

Global Warming

Greenhouse Gases



Emissions, Why Are They Bad? Unburned Hydrocarbons

Promotes Conversion of NO Into Ozone.

Reactivity of Components Vary – Methane - Low

– Butane - High

Therefore Regulations May Specify TotalHydrocarbons, Non-Methane HC, or Non-

Methane Non-Ethane HC



Global Warming

INCREASED REFLECTION BY ATMOSPHERE OF INFRA-RED

RADIATION FROM THE EARTH WARMS THE CLIMATE.

SUN INFRA-RED

RADIATION

greenhouse

gases

ATMOSPHERE



Why Emissions Are Good For Gas

Business!

18

9

5

1.5 1.3 0.5 0.3 0.3

0

2

4

6

8

10

12

14

16

18

20

22

N O x ( g / b h p -

h r )

g/bhp-hr (grams per brake horsepower hour)

Stoich

Gas

D3600 D3500B Turbine

Std.

Comb.

G3500 Turbine

SoLoNOx

G3600 3-Way

Catalyst

(Dual

Stage)



What To Do About Emissions

Reduction Via Control in Combustion Chamber Lean Burn-Cooler Combustion Reduces NOx but Increases

CO

Retard Timing-Cooler Combustion

Reduction Via Aftertreatment of Exhaust Gas

Thermal Reactors Oxidize CO, HC - Corr. Gases (800+ C

Exh Temps-$200/hp)

Catalytic Converters (3-way, Oxidation, SCR)

Particulate Traps (Only Diesel)



NOx Characteristic

NOx

LAMBDA=(A/F actual)/(A/F stoich)

2

4

6

8

10

12 14

16

18

20

22

0.8

Rich Burn LAMBDA Lean Burn

0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 0 O 2

( % D R Y )

N O x

( g / h p - h r )

EXHAUST

OXYGEN

COMBUSTION

TEMP



CO Characteristic

0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 0

2

4 6

8

10

12

14 16

18

20

22

24

C O ( g / h p - h r )

CO

Rich Burn LAMBDA Lean Burn

lack of O 2

Exhaust

Oxygen



NOx (mg/Nm3)

Electrical

efficiency

35

36

37

38

39

40

41

42

43

100 200 400 600 800 1000

1/2 TA Luft TA Luft

Denmark NOx

regulation

Efficiency

Range



What To Do About Emissions

Catalytic Converters

Oxidation Catalyst Used with Lean Burn Reduces CO (50-90%) and HC (50%)

Uses Platinum and Palladium

CO2

H2O

CXH Y

CO

O2

Oxidation Catalyst



Emissions - Units

G / bhp-hr

Reported at Actual Exhaust 02

Use to Calculate Tons / Yr , Lb / Day , etc…..

PPM @ X 02%

Corrected to 15% 02

Use to Compare Other Manufacturers

http://localhost/var/www/apps/conversion/tmp/scratch_4//h8file01/PCCOMMON/MORSEDA/Great%20Lakes%20Region/DM5102%2001%20p1(ppm).pdf

http://localhost/var/www/apps/conversion/tmp/scratch_4//h8file01/PCCOMMON/MORSEDA/Great%20Lakes%20Region/DM5102%2001%20p1(ppm).pdf



Emissions - Conversions

PPM measured * (20.9-X% O2)

PPM @ X% O2 = --------------------------------------

(20.9-%O2 measured)

Conversion to Different Exhaust Oxygen Levels

1 ppm NOX = 2.052 mg NOx/Nm3 Exhaust Gas1 ppm CO = 1.25 mg CO/Nm3 Exhaust Gas

1 ppm CH4 = 0.716 mg CH4/Nm3 Exhaust Gas



Conclusion

What are Emissions?

Why are They Bad?

How are They Formed?

What to do About Them.



OPERATION AREA FOR LEAN BURN

STOICHIOMETRIC MIXTURE

LEAN

LEAN MISFIRE

RICH MISFIRE

RICH ESTANDARD

TA LUFT

BEST ECONOMY

0,2

0,4

0,6

0,8

1,0

1,2

1,4

1,6

1,8

L A M B D

A

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210

M.A.P. kPa

D E T O N A T

I O N

gas engine air/fuel adjustment

Documents