蒸発ガス、給油時蒸発ガスの排出実態Evaluation of Evaporative and Refueling

Emissions in Japan using PTR-MS

National Traffic Safety and Environment LaboratoryHiroyuki YAMADA

National Institute for Environmental StudiesSatoshi INOMATA, Hiroshi TANIMOTO

1

大気環境学会シンポジウム“蒸発ガス・給油時蒸発ガスを考える”16th November, 2015

Evaporative emissions

Carbon Canister

Fuel Tank

Active Carbon

Intake Manifold

Fuel Vapor

Trapped

Release

Clean Air

Emissions by expanding gasoline vaper inside the tank→ Fuel Vapor Generation (FVG)

Permeation of gasolines through a tank and tube→ Permeation

2

Gasoline car is equipped with a carbon canister to trap FVG.

Release of FVG to atmosphere when a carbon canister is fully filled with FVG is called for “Breakthrough”

Refueling emissions

Prevention Technology

Emissions that Gaseous fuel in the tank is pushed out by filled fuel during a refueling process

3

Fuel tank

Gasoline

Gasoline Vapor

Gasoline Vapor

ORVR

Dispenser

Gasoline

Gasoline

Vapor

Vapor

Underground Tank

Stage II Refueling emissions are sent to underground tank.

Refueling emissions are trapped by canister

Kanagawa Prefecture HP

Contents

• Evaluating evaporative emissions during 3 days parking events• Estimating annual total evaporative emissions in Japan

4

Evaluation of evaporative emissions

Evaluation of Refueling emissions• Evaluating refueling emissions at various temperature• Evaluating effects of preventing technologies

Evaluation of Ozone Formatting Potentials • Estimating MIR of evaporative and refueling emissions• Comparing them with MIR of tested gasoline

This presentation was based on the discussion listed below.H. Yamada, S. Inomata, H. Tanimoto, “Evaporative Emissions in Three-Day Diurnal Breathing LossTests on Passenger Cars for the Japanese Market”, Atmospheric Environment 107, 166-173(2015)H. Yamada, S. Inomata, H. Tanimoto, “Refueling Emissions from cars in Japan: Compositions,Temperature Dependence and Effect of Vapor Liquefied Collection System”, Atmospheric Environment120, 445-462(2015)H. Yamada, “Contribution of Evaporative Emissions from Gasoline Vehicles toward Total VOCEmissions in Japan”, Science of the Total Environment, 449, 143-149, (2013)

Evaluation of evaporative emissions

Evaluation of Refueling emissions

Evaluation of Ozone Formatting Potentials

15

20

25

30

35

40

0 6 12 18 24

Tem

pera

ture

(℃)

Time (h)

SHED Test (Diurnal Breathing Loss)Evaporative emissions were evaluated using Sealed Housing for. Evaporative Determination (SHED).

6

0

1

2

3

4

5

6

Day 1 Day 2 Day 3

THC

(g/d

ay)

THC in three continuous DBL test

The most of FVG was trapped by the canister in Day1.Emissions increased because of the appearance of breaktrough emissions.

Permeation only

Permeation + Breakthrough

Tested Cars for Evaporative Emissions

7

9 cars were tested.FC was produced by European manufacturerFM was produced by US manufacturer

Name MA MB MC CA CB CC CD FC FM

Maker Toyota Subaru Nissan Toyota Mitsubishi Toyota Toyota Smart Ford

Category Mid-size Mid-size Mid-size (van)

Compact Compact Conpact

(van)Conpact

(van) Compact SUV

Travel millage (km) 32,000 114,343 168,021 29,678 8,700 15,452 51,588 48,813 7,684

Car age (year) 5.5 5.8 13.6 4.5 2.7 4.6 7 3.2 0.8Tank capacity

(L) 50 50 76 40 45 55 55 33 70

Displacement (L) 1.8 2 3.5 1.5 1.5 2 2 1 2

Vehicle weight (kg) 1260 1420 2000 1050 1090 1640 1580 840 2020

0

2

4

6

8

10

12

day1 day2 day3

THC

(g/d

ay)

MA MBMC CACB CCCD FCFM

Japanese regulatry

Emissions during 3 days Parking Events

8

4 out of 6 Japanese cars exhibited breakthrough emissionsEmission of US car was the lowestBreakthrough appearance is not “On-Off” event, it appears gradually

US car

EU car

Estimation of amount of breakthrough emisssionsReddy Equation EFVG_gal = AeB(RVP)(eCT2-eCT1)

EFVG_gal: Evap. emissions per space CT2: Max. Temp. CT1:Min. Temp.

theoretical Equation𝐸𝐸𝐹𝐹𝐹𝐹𝐹𝐹 = 𝑀𝑀𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓 × 1 − 𝑇𝑇𝑀𝑀𝑀𝑀𝑀𝑀

𝑇𝑇𝑚𝑚𝑚𝑚𝑚𝑚× 273

𝑇𝑇𝑀𝑀𝑀𝑀𝑀𝑀× 𝑃𝑃𝑓𝑓𝑓𝑓

𝑃𝑃𝑀𝑀𝑚𝑚𝑎𝑎× 𝐹𝐹𝑡𝑡𝑀𝑀𝑚𝑚𝑡𝑡

22.4

EFVG:Evap. Emissions Mfuel: molecular weight of fuelPfv: Vapor pressure of fuel Tmax: Max. temp. Tmin:Min temp.

05

10152025303540

0 20 40 60 80 100

Em

issi

on (

g)

Fuel Occupancy in the tank (%)

ExperimentalThis study with = 65 kPaThis study with = 100 kPaby Reddy Equation

P fv

P fv

9

Theoretical equation with Vapor pressure = 100kPa well reproduced experimental resultsReddy equation overestimated.

10

15

20

25

30

35

0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00

(deg

ree

C)

Tank Temp. UpperTank Temp. LowerAmbient Temp.Temp. at Fuchu observatory

(a) Temperature

0

2

4

6

8

10

0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00

Win

d ve

loci

ty (m

/s)

North windSouth wind

(b) Wind velocity and direction at Fuchu observatory

0

1

2

3

4

020406080

100120

0:00 0:00 0:00 0:00 0:00

Rai

nfal

l rat

e (m

m /

h)

Suns

hine

rat

io (%

)

Time

Sunshine ratio

Rainfall rate

23rd May 2012 24th 25th 26th

(c) Sunshine ratio and Rainfall rate at Fuchu observatory

Estimation of Fuel Temperature

Fuel tank temperature profiles are important parameters for estimating breakthrough emissions but it was similar to ambient temperature

Fuel tank temperature during parking in shinny car lots

10

Evaporative Emissions Map

Emissions per car

11

Total emissions in each prefecture

Emissions from each car was high at inland area.Total emissions were high at big cities (because of high population)

12

Various Sources of VOC with Gasoline cars

Tailpipes: 18,000 ton

Evaporative: 33,000 ton

Refueling: 110,000 ton

Total VOC emissions in Japan: 86,0,000 metric ton

Evaluation of evaporative emissions

Evaluation of Refueling emissions

Evaluation of Ozone Formatting Potentials

Test for Refueling Emissions

14

• Setting gasoline dispenser next to the SHED• Refueling emissions were evaluated using normal SHED• Effect of On-board Refueling Vapor Recovery (ORVR) and Vapor

Liquefied Collection System (VLCS) were also evaluated

SHED VLCS ORVR

Evaluation of refueling emissions

15

0

0.5

1

1.5

2

2.5

5 10 15 20 25 30 35

THC

(g/L

)

Temperature( ̊C)

ExperimentsMoE, JapanMOVE2010

0.000.200.400.600.801.001.201.401.60

UA UB UC UD UE UF UG UH Ave.

(g/L

)

Emissions at 20℃ Temperature dependence

Name UA UB UC UD UE UF UG UHCategory Compact Compact mini-van Van mid-size small Wagon WagonMaker Mitsubishi Toyota Toyota Toyota Toyota Honda Toyota HondaDisplacement (L) 1.5 1.5 2.0 2.0 1.8 0.7 2.4 2.4Vehicle Weight (kg) 1090 1050 1580 2140 1260 970 1770 1870

8 Japanese cars were evaluated

Refueling Emissions Preventing Technologies

16

Dispenser

Underground Tank

Gasoline

Gasoline

VaporVapor

Condenser

Liquefied Vapor

Gasoline Trap

Exhaust

Pump

VLCS

Release Valve

ORVR

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

5 10 15 20 25 30 35

Emis

sion

s rel

ativ

e to

unc

ontro

lled

Temperature ( ̊C)

VLCSORVR

VLCS

Results (Emission relative to uncontrolled )

Emissions with ORVR and VLCS was almost similar (5% to uncontrolled)

Vapor liquefied Collection System (VLCS) was similar to Stage II, developed by Tatsuno. Trapped gasoline vapor was liquefied and send to dispenser.

Evaluation of evaporative emissions

Evaluation of Refueling emissions

Evaluation of Ozone Formatting Potentials

00.20.40.60.8

11.21.41.6

16 30 44 58 72 86 100

114

128

142

156

170

184

MIR

Alkane

normal

branched

Why Composition analysis of VOC is needed?

18

0

2

4

6

8

10

12

14

78 92 106 120 134 148 162

MIR

Aromatics

0

2

4

6

8

10

12

14

28 42 56 70 84 98 112126140

MIR

AlkeneAromatics Alkanes Alkenes

MIR =Increased amount of Oxidant (g)

Increased amount of VOC (g)

NO2

NO

OH

HO2

RO2

RO

O3

NO

NO2

O3

H2O2

ROOH

VOC

CO

O2

hν

hν

NO2

NO

OH

HO2

RO2

RO

O3

NO

NO2

O3

H2O2

ROOH

VOC

CO

O2

hν

hν

VOCs from cars have been regulated as non-methane hydrocarbon (NMHC) or total hydrocarbons (THC)

VOCs increases grand level ozone and its effects depend on their structures

Selection of Methodology

19

• Obtaining Mass of molecules which was ionized by various technologies• Features of methodology depends on the ionization process

Ionization Method

Mass Spectroscopy

Method Multi-Detection Realtime QuantificationElectron Impact ○ × △

Photoionization △ ○ △

PTR ○ ○ ○

Proton Transfer Reaction(PTR）

H3O+ + M → MH++H2O

This method can not ionize (measure) alkane species

Pure AirSample

pump

pump

Drift tube Quadrupole MSIon source

pump

NO+ Chemical Ionization Mass Spectrometry

NO+ + VOC VOC+, [VOC‒H]+

NO+VOC+

[VOC‒H]+

VOC

NO+ + VOC → [VOC‒H]+ + HNO

NO+ chemical ionization:

IONICON PTR+SRI-MSProton Transfer Reaction plusSelective Reagent Ion-Mass Spectrometer

http://www.ionicon.com/

discharge

VOC = Alkane

VOC = Alkene, Aromatics

NO+ + VOC → VOC+ + NO

0

0.1

0.2

0.3

M56(C4)

M70(C5)

M84(C6)

M98(C7)

M112(C8)

Mas

s R

atio

PermeationBreakthroughFuel

0

0.1

0.2

0.3

0.4

0.5

M58(C4)

M72(C5)

M86(C6)

M100(C7)

M114(C8)

Mas

s R

atio

PermeationBreakthroughFuel

Compositions of Evaporative Emissions

21

Composition of Breakthrough differed from that of permeation.Almost no aromatics in breakthrough.Permeation and Breakthrough consists of smaller species than fuel.High C4 and C5 alkane and alkene in case of breakthrough.

Alkanes

Alkenes

0

0.05

0.1

0.15

0.2

M78(Benz.)

M92(Tol.)

M106(C8)

M120(C9)

M128(Nap.)

Mas

s R

atio

PermeationBreakthroughFuel

Aromatics

00.5

11.5

22.5

33.5

44.5

Fuel Permeation Breakthrough

MIR

×R

atio

Aromatics Alkane Alkene

Compositions and MIR of Evaporative Emissions

22

0

0.2

0.4

0.6

0.8

1

Fuel Permeation Breakthrough

Rat

io

Aromatics Alkane Alkene

Compositions MIRs

Main components was alkaneEffect of aromatics alkenes were high because of their higher MIRsBreakthrough had the highest MIR because of C4 and C5 alkenes→ MIRBreakthrough = MIRFuel + 0.5 MIRPermeation = MIRFuel

Composition of Refueling Emissions

23

0.0

0.2

0.4

0.6

0.8

1.0

Tested Fuel RefuelingEmissions

Alkanes

Alkenes

Aromatics

Di-enes

0

1

2

3

4

5

Tested Fuel RefuelingEmissions

Alkanes

Alkenes

Aromatics

Di-enesCompositions MIR

No aromatics and higher effect of C4 and C5 alkenes

Almost similar to breakthrough of evaporative emissions

0.0

0.1

0.2

0.3

0.4

0.5

C4 C5 C6 C7 C8 C9M

ass

ratio

RefuelingEmissions(UB)

Alkanes

0

0.05

0.1

0.15

0.2

C4 C5 C6 C7 C8 C9

Mas

s ra

tio

RefuelingEmissions(UB)

Alkenes

0

0.02

0.04

0.06

0.08

0.1

0.12

M78 M92 M106M120M134M128M148

Mas

s ra

tio

RefuelingEmissions (UB)Fuel

AromaticsDetailed Compositions

Species Profiles during DBL Tests

PTR + SRI – MS can obtain profiles of various species

24

15

20

25

30

35

40

0 5 10 15 20

Tem

pera

ture

( ̊C

)

Time (hour)

(a) Temperature

0

10

20

30

40

0 5 10 15 20

Con

cent

ratio

n (p

pb)

Time (hour)

m78m106m120

(b) Aromatics

0

50

100

150

200

0 5 10 15 20

Con

cent

ratio

n (p

pb)

Time (hour)

m72m86m100

(c) Alkanes

0

1000

2000

3000

4000

5000

0 5 10 15 20

Con

cent

ratio

n (p

pb)

Time (hour)

(d) Pentane (breakthrough)

Decrease of low volatility species and high concentration species were observed.

Traditional analysis (before /after test measurement) possibly underestimates these emissions

y = (-0.0055±0.02144)x + 4.4526±0.4706

3

3.5

4

4.5

5

5 10 15 20 25 30 35

MIR

Temperature (̊C)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

5 10 15 20 25 30 35

Rat

io fr

om 2

0(̊C

)

Temperature (̊C)

AromaticsAlkanesAlkenesDi-enes

Temperature Dependence of Refueling EmissionsDetailed compositions

25

Compositions

Compositions of refueling emissions depended on the temperature.

MIR slightly decrease as increasing the temperature.

00.20.40.60.8

11.21.41.61.8

5 10 15 20 25 30 35R

atio

from

20(̊

C)

Temperature (̊C)

C4C5C6C7C8

(b) Alkanes

00.20.40.60.8

11.21.41.61.8

5 10 15 20 25 30 35

Rat

io fr

om 2

0(̊C

)

Temperature (̊C)

M78 (Benzene)M92 (Toluene)M106M120M134M128 (Naphthalene)

(a) Aromatics

00.20.40.60.8

11.21.41.61.8

5 10 15 20 25 30 35

Rat

io fr

om 2

0(̊C

)

Temperature (̊C)

C4C5C6C7C8

(d) Di-enes

00.20.40.60.8

11.21.41.61.8

5 10 15 20 25 30 35

Rat

io fr

om 2

0(̊C

)

Temperature (̊C)

C4C5C6C7C8

(c) Alkenes

Change of MIR

Conclusion

26

MIRRefueling =MIRBreakthrough = MIRFuel + 0.5MIRPermeation = MIRFuel

• 4 of 6 Japanese cars exhibited breakthrough emissions in 3 DBL tests• Breakthrough emissions appeared as gradual increased emissions• Total evaporative emissions in Japan was estimated to 33,000 ton.

Evaluation of evaporative emissions

Evaluation of Refueling emissions• Refueling emissions at 20 ℃ was 1.02 ± 0.20 g /L.• MoE estimation overestimated the emissions (because of no term of RVP)• Emissions with ORVR and VLCS were 5% of uncontrolled emissions.

Evaluation of Ozone Formatting Potentials • Impact of C4 and C5 alkene was high on MIR of each emission