6th High Temperature Solid Looping Cycles Network …ieaghg.org/docs/General_Docs/6_Sol_Looping/2_Anabel_Serrano... · Chemical Looping Combustion with liquid fuels in a 1 kWth unit

Chemical Looping Combustion withliquid fuels in a 1 kWth unit using a

Fe- based oxygen carrier

6th High Temperature Solid Looping Cycles Network Meeting1 – 2 September 2015

A. Serrano, F. García-Labiano L. F. de Diego, Pilar Gayán Alberto Abad,

Juan AdánezInstituto de Carboquímica, CSIC-ICBCombustion and Gasification group

1. Introduction

2. Experimental

3. Results

4. Conclusions

1. Introduction

3

Introduction

Ed Dlugokencky and Pieter Tans, NOAA/ESRL (www.esrl.noaa.gov/gmd/ccgg/trends/)

Recent global monthly mean CO2, Mauna Loa Observatory

4

Our society is at a turningmoment to develop an effectivestrategy to adress climate change

400 ppm CO2

IPCC warned that it is imperative to take urgentand effective actions to reduce global emissions

Introduction

5

CCS technologies play an important role as they are capable of achieve 14% of the reductions needeed to keep the rise in global temperature below 2 ºC [1].

2%

Powergeneration

Efficiency and fuel switching

7%

Nuclear End use fuel switching

9%

CCS

30%

Renewables End use energyefficiency

38%

14%cumulative CO2

emission reductions

[1] Global CCS Institute 2014, The Global Status of CCS: 2014,Melbourne, Australia.

Introduction

6

CLC is based on the transfer of oxygen from air to fuel by means of an OC which is continuouslyreduced and oxidized. Doing so, direct contact between air and fuel is avoided and a pure streamof CO2 is produced.

Fuel

Condenser

H2O

Cyclone

CO2

Unreacted N2 + O2

Air

FUEL REACTOR

AIRREACTOR

Me

MeO

Introduction

7

Renewable fuels Fossil fuels

[2] RFA, Renewable Fuels Association: 2015 Ethanol Industry Outlook http://www.ethanolrfa.org/[3] van Straelen, J., Geuzebroek, F., Goodchild, N., Protopapas, G., Mahony, L. CO2 capture for refineries, a practical approach (2010) International Journal of Greenhouse Gas Control, 4 (2), pp. 316-320

They have the advantage of achieving negativeCO2 emissions

EtOH

Its production and use have increased dramaticallysince early 2000. In 2014, ≈93.7 billion litres ofethanol were produced and this trend is expectedto continue [2]

In the transition to a low-carbon ecnonomy, theimplementation of CLC technology with liquid fuelsfrom refineries could reduce 1 billion metric tonsCO2/year [3]

Diesel – Engine oil

They were selected as representatives fuels obtained inrefieneries, but the ultimate goal in future works willinvolve the use of heavy residual oils

Liquid fuels

8

AIM

This work intended to analyze the employability of

ethanol, diesel and engine oil as fuels in a

continuous CLC unit with a Fe- based OC

2. Experimental

9

Experimental

10

AIM

Given the relevance of theimpurities in the performance of CLC, these compounds weredetermined

Elementaryanalysis

Distillationcurves

FUELS

Three different behaviours wereobserved according to theirdifferent molecular structure

* Ash content <0,01 %m/m

Temperature (ºC)

0 100 200 300 400 500

Dis

tilled

fra

cti

on

(vo

l.%

)

0

20

40

60

80

100

EtOH

Diesel

Engine oil

Experimental

11

AIM

OC developed by ICB-CSIC [4]

Prepared by incipient wetness impregnation

To ensure that OC mantained its propertiesafter operation, the fresh OC was characterized

Fe20-γAl2O3

OXYGEN CARRIER

[4] Gayán, P., Pans, M.A., Ortiz, M., Abad, A., De Diego, L.F., García-Labiano, F., Adánez, J. Testing of a highly reactive impregnated Fe 2O 3/Al 2O 3 oxygen carrier for a SR-CLC system in a continuous CLC unit (2012) Fuel Processing Technology, 96, pp. 37-47.

Experimental

12

1 kWth CLC FACILITY

1.- Fuel reactor

2.- Loop seal

3.- Air reactor

4.- Riser

5.- Cyclone

6.- Solids valve

7.- Solids valve

8.- Filters

9.- Pumps

10.- Evaporator

Components2 interconnected fluidized bedreactors, a riser, a cyclone, avalve to manage solid circulationflow and a loop seal to preventgas mixing between reactors

DimensionsFR 0,026-0,085 m. i. d.AR 0,052 m. i. d.

Fuel supplyIt was controlled by peristalticpumps.The fuel flow was completelyevaporated in a furnace beforeit reached the FR.

Gas Chromatograph quantifiedHCs.

Fuel

Experimental

13

DATA ANALYSIS

Oxygen carrier reductionEthanol

C2H5OH + 6 Fe2O3 + 12 Al2O3↔ 12 FeAl2O4 + 2 CO2 + 3 H2O

Diesel

C15H29 + 44,5 Fe2O3 + 89 Al2O3↔ 89 FeAl2O4 + 15 CO2 + 14,5 H2O

Engine oil

C18H34 + 53 Fe2O3 + 106 Al2O3↔ 106 FeAl2O4 + 18 CO2 + 17 H2O

Oxygen carrier oxidation

4FeAl2O4 + O2 2Fe2O3 + 4 Al2O3

𝜼𝒄 =2xCO2

+xCO+z∙xCxHyOz out ∙Fout− z∙(xCxHyOz)in∙Fin

b∙(xCxHyOz)in∙Fin

Ф =FFe2O3b∙Ffuel

Combustion efficiency

Oxygen carrier to fuel ratio

CO2 capture efficiency

𝜼𝒄𝒄 =xCO2

+xCO+X∙xCxHyOz out ∙Fout

(xCxHyOz)in∙Fin

3. Results

14

Results

15

ETHANOL

• In the range 800-900ºC, an increase in T produced an increase in ηc as OC reactivity isimproved with T

• Regarding gas product distribution, light hydrocarbons were never measured.

• CO2 was the major compound together with a mixture of CO+H2+CH4 to a lesser extent

1 2 3 4 5

Co

nc

en

tra

tio

n (

vo

l. %

, d

ry b

as

is)

0

20

40

60

80

100

CO2

CO

H2

CH4

Temperature 900ºC

1 2 3 4 5

Co

mb

usti

on

eff

icie

nc

y,

c (

%)

50

60

70

80

90

100

EtOH 800ºC

EtOH 900ºC

Results

16

DIESEL

• Regarding gas product distribution, againmixture CO+H2+CH4 were the only compoundsdecreasing ηc .

• As in the previous case, CH4 was measuredwhich suggests that CH4 could be anintermediate on HCs conversion to CO2.

• In the range 800-900ºC, temperature had a slight effect on ηc

1 2 3 4 5

Co

nc

en

tra

tio

n (

vo

l. %

, d

ry b

as

is)

0

20

40

60

80

100

CO2

CO

H2

CH4

Temperature 900ºC

0 1 2 3 4 5

Co

mb

us

tio

n e

ffic

ien

cy,

c (

%)

50

60

70

80

90

100

Diesel 800ºC

Diesel 900ºC

Results

17

ENGINE OIL

• Only the mixture CO+H2+CH4 decreaed ηc and CH4 remained constant suggesting again that itcould be a stable intermediate.

• In the range 800-900ºC, temperature played animportant role for Ф<1,8

1 2 3 4 5

Co

nc

en

tra

tio

n (

vo

l. %

, d

ry b

as

is)

0

20

40

60

80

100

CO2

CO

H2

CH4

Temperature 900ºC

1 2 3 4 5

Co

mb

us

tio

n e

ffic

ien

cy,

c (

%)

50

60

70

80

90

100

Engine oil 800ºC

Engine oil 900ºC

Results

18

In accordance with the results obtained, engine oil performed better

despite its greater difficulties to be handled.

Thus, long term tests and a comprehensive OC characterization were

done to analyze deeper the influence of impurities

Results

19

LONG TERM TESTS - ENGINE OIL

• 50 h burning fuelCarefull assessment of thecombustion process

• Combustion efficiency wasunaffected by operationhours/impuritiesFor a given φ value, almost same ηc

was achieved at different operationhours

• Effect of SThe OC did not show any sign ofdeactivation or poisoning

1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5 5,0

Co

mb

us

tio

n e

ffic

ien

cy,

c

(%

)

70

75

80

85

90

95

100

Engine oil

Long term tests

Temperature 900ºC

24 h

20 h30 h7 h

3 h50 h

40 h

Results

20

• Reactivity tests in TGA

Fresh and used OC particles weresubjected to succesive redox cyclesto study its evolution duringoperation

• Conversion VS time curves

As shown, OC reactivity was hardlyaffected by operation hours or thepresence of impurities

LONG TERM TESTS - ENGINE OIL

Time (seconds)

0 20 40 60 80 100 120

So

lid c

on

vers

ion

0,0

0,2

0,4

0,6

0,8

1,0

Fresh

Used

Temperature 950ºC Patm 15% vol. CH4 as reducing gas

Results

21

• SEM-EDX analyses

Particles were rounded due tooperation hours in ICB-CSIC-liq1.

Fe distribution was homogeneousalong the cross section, both onfresh and used.

Regarding possible deposition of impurities on the particles, no significant amount of none of themwere detected.

Fresh particles After 50 h

LONG TERM TESTS - ENGINE OIL

dp ( m)

0 50 100 150 200

a.u

.

Fe

dp ( m)

0 50 100 150 200

a.u

.

Mg

Ca

Ba

Zn

Pb

S

P

Fe

Results

22

Ф =FFe2O3b∙Ffuel

• 200 h successful operation

During the experimental campaign200 h were achieved with the samebatch of particles

• Results summary

ηc obtained values provide a quick overview of the mainfindings. EtOH and diesel followed thesame trend but engine oilbehaved contrary to expectationsbetter than the others at low φvalues likely due to the differentthermal decompositionmechanism

SUMMARY

1 2 3 4 5

Co

mb

us

tio

n e

ffic

ien

cy,

c

(%

)

50

60

70

80

90

100

EtOH

Diesel

Engine oil

Temperature 900ºC

23

4. Conclusions

Conclusions

24

• Three different liquid fuels, ethanol, diesel and engine oil, were evaluated in a 1kwth CLC continuous unit using a Fe- based oxygen carrier prepared byimpregnation method.

• A total of 200 hours of operation were successfully accomplished with the samebatch of Fe20-γAl2O3 particles

• The three liquid fuels behaved properly under CLC conditions working with Fe20-γAl2O3 oxygen carrier

• The behavior of engine oil was especially noteworthy as it was able to achieveeven better combustion efficiencies at low φ values despite its greater molecularcomplexity

Thanks for attending this presentation

Anabel Serrano

Instituto de Carboquímica, CSIC-ICB

Combustion and Gasification group

Zaragoza, Spain

[email protected]

Acknowledgements

This work partially supported by the Spanish Ministry for Science and Innovation (MICINN project ENE2011-26354) and the EuropeanRegional Development Fund (ERDF) and by the Government of Aragón (Spain, DGA Ref. T06). A. Serrano also thanks the Spanish Ministry of Economy and Competitiveness for the F.P.I fellowship.

Chemical Looping Combustion with liquid fuels in a 1 kWth unit using Fe- based oxygen carriers