Biomass Technology Research Center (BTRC),

National Institute of Advanced Industrial

Science and Technology (AIST), Japan

Tomohisa MIYAZAWA, Kotetsu MATSUNAGA,

Toshiaki HANAOKA, Nobuhisa TANABE,

Shinji FUJIMOTO, Tomoaki MINOWA,

Satoshi HIRATA, Kinya SAKANISHI

7th Asian DME Conference ,Niigata, Nov.17 2011

The synthesis of bio dimethyl ether (DME) & process estimation on economy

The synthesis of bio dimethyl ether (DME) & process estimation on economy

7th Asian DME Conference

Gasification &Bio-DME synthesis Gasification

Gas cleaning Compression

We have carried out consecutive plant-operation from biomass to DME on a bench-scale

DME synthesis Biomass

Bio-DME

Process estimation on economy based on the plant operation data

Based on the plant operation

data, we studied effect of

pressure of DME synthesis in

biomass to DME process on the

economy.

Gasifier

Gas cleaning CO2 removal

DME synthesis

Biomass Process estimation on economy

Process simulation Oxygen-

enriched air

Compre

-ssion

Bio-DME

Objective of our work

Synthesis gas Biomass

Bio-DME

O C C

H

H

H

H

Gasification

Catalytic synthesis

● To produce DME from biomass.

● Bio-DME is regarded as carbon neutral resource.

Natural gas

Coal

Biomass

Gasification &Bio-DME synthesis process

Gasification with

oxygen enrichment air

Tar removal by

wet gas cleaning

Desulfurization &

Removal of CO2 Compression &

storage

We have carried out consecutive reaction

from gasification to DME synthesis.

DME synthesis

in the fixed-bed

reactor.

Feedstock

HHV

C H N S a)

O b) Moist. VM FC Ash MJ/kg dry basis

51.0 6.0 0.2 0.015 42.8 10.5 73.1 15.8 0.6 19.7

a) Ion chromatography

b) By difference

Proximate analysis/wt% Ultimate analysis/wt% dry basis

Eucalyptus (20-30 mm)

30 mm

Oxygen enrichment air gasification by down-draft fixed bed gasifier

Wood feed rate: 9-18 kg/h,

Temperature: 800-1200 oC

Gasifying agent：Air, Oxygen enriched air

Oxygen content in gasifying agent：21-90%

Air + O2

grate

dust

TC for Combustion zone

TC for Reduction zone

product gas

char

woody biomass

cyclone

ΔP

Level sensor

roots blower wood vinegar

0

200

400

600

800

1000

1200

0

10

20

30

40

50

60

9:00 10:00 11:00 12:00 13:00 14:00 15:00

Tem

pera

ture

/oC

Time on stream

Pro

duct

gas flo

w r

ate

/Nm

3/h

Product gas flow rate

Combustion zone

Oxygen enrichment air gasification

by down-draft fixed bed gasifier

Stable & high conversion gasification can be carried out

Biomass feed flow rate: 9.0 kg/h, O2 content in gasifying agent: 28 vol%

Product distribution/C-mol% Product gas composition/vol%

Gas Wood vinegar Dust Char CO H2 CH4 CO2 N2

96.1 0.1 0.2 3.6 31.2 25.6 2.7 0.4 40.1 <5ppb

Sulfur compound

Reduction zone

DME synthesis reaction

Total reaction: 3CO+3H2CH3OCH3+CO2

γ-Al2O3 catalyst (N612N, Nikki Chemical Co., Ltd.)

Specific surface area Pore volume Composition/%

m2/g cm3/g Al2O3

166 0.37 95.9

Methanol synthesis: CO+2H2 CH3OH ………… Cu-Zn

Methanol dehydration: 2CH3OH CH3OCH3+H2O… γ-Al2O3

Water gas shift reaction: CO+H2O CO2+H2 ………… Cu-Zn

Cu-Zn catalyst (N211, Nikki Chemical Co., Ltd.)

Specific surface area Pore volume Composition/%

m2/g cm3/g CuO ZnO

32 0.15 48.7 44.6

Continuous DME synthesis reactor

Water trap

(～2℃)

Fixed-bed reactor DME trap (～-35℃)

Control unit

Gas flow

Catalyst: Cu-Zn cat./γ-Al2O3=1(wt/wt) 500-1000 g

Pretreatment:

Hydrogen reduction:N2/H2=1/1 500 ml/min 2 h, 250 oC

DME synthesis:

Reaction pressure: 0.98 MPa (<1 MPa)

Reaction temperature: 210, 230, 250 oC

Gas flow rate = 200-1500 ml/min

Gas composition(Gasification gas in the bench-plant): CO H2 CH4 CO2 N2 COS, H2S 31.2% 25.6% 2.7% 0.4% 40.1% <5ppb

Reaction condition (DME synthesis)

Results of DME synthesis from gasification gas

Effect of W/F on the DME synthesis

Feed gas flow rate [L/min]

1.5 1.0 0.5 0.2

T=250 oC

P=0.98 MPa

● DME yield increased with an increase in W/F. ● 3CO + 3H2 ⇋ CH3OCH3 + CO2 has been proceeding.

DME

MeOH

● Methanol yield was less than 1/100 of DME. ● Amount of DME(mol)

≒3×Decrease of CO or H2

Ethanol

refrigerant

Ethanol refrigerant

+ activated carbon

Boiling point of the DME : -24oC

Ethanol refrigerant temp.： -35oC

Dry ice refrigerant temp. ： -80oC

DME concentration & recovery rate after trap

● Just only cooling is not enough to recover DME. ● Combination of cooling & adsorption to activated carbon can capture almost all DME in the outlet gas.

DME recovery methods

Long time reaction and DME recovery

Results of DME production for long time

● We have succeeded in the stable continuous synthesis of DME over 200 h. ● Recovering 100 g of liquefied bio-DME.

W/F=75.8 kg h/m3

T=230oc P=0.98 MPa

Succeed in recovery

of liquefied bio-DME

0

20

40

60

80

100

0

5

10

15

20

25

30

0 100 200 300 400 500 600

CO

convers

ion [

%]

Pro

duct gas c

om

positio

n [

vol%

]

Time on stream [h]

CO

H2

CO2

DME

CO conv.

Results of DME production using upgraded gas

Upgrading of gasification & DME synthesis

W/F=75.8 kg h/m3

T=230oc P=0.98 MPa

Gas composition/%

CO H2 CH4 CO2 N2

48.9 39.8 4.3 2.6 4.1

Produced gas composition

in the high O2 content

gasification.

● Syngas content in the feed gas could be increased(57→89%). ● DME yield also could be increased.

Bio-DME vehicle running demonstration

Finally we have operated DME synthesis total 1000 h

& succeeded in the recovery of 1.1 kg bio-DME.

● DME vehicle promotion committee, Japan(DMEVPC) have demonstrated bio-DME vehicle running test on May 18, 2010. The mixture of our synthesized bio-DME with DME produced from natural gas at Niigata DME plant was used as DME fuel.

Process estimation on economy based on the plant operation data

Gasifier

Gas cleaning

CO2 removal

DME synthesis

Biomass Process estimation on economy

Process simulation Oxygen-

enriched air

Compre

-ssion

Bio-DME

Based on the plant operation data, we studied effect of pressure

of DME synthesis in biomass to dimethyl ether (DME) process

on the economy.

5 MPa or 0.98 MPa

unit Base cost Scale

factor Base scale

Overall installation

factor

Maximum

size

Compressor 12.9 0.85 13.2 MWe 1.86 -

Slurry reactor 36.5 0.72 362 m3 1 365 m3

Costs of system components in M€2002*

* ) Hamelinck Et al, ENERGY, 29, 1743-1771 (2004)

0

0.2

0.4

0.6

0.8

1

P=5.0MPa P=0.98MPa

Rel

ativ

e un

it c

ost

of s

yste

m c

ompo

nent

[-]

Slurry

ReactorCompressor

0

0.2

0.4

0.6

0.8

1

P=5.0MPa P=0.98MPa

Rel

ativ

e po

wer

con

sum

ptio

n [-

]

Effect of pressure on the process costs

Relative cost of compressor for 0.98 MPa is about 60% of those for 5.0 MPa

and the cost of slurry reactor for 0.98 MPa is about 20% of 5.0 MPa.

Cost dependence on the

components size

C1=C0×(S1/S0)R

1. We succeeded in the continuous synthesis of

DME from biomass derived gasification gas at

low pressure below 1MPa and recovery of about

1.1 kg of liquefied bio-DME.

2. It was found that DME synthesis at low pressure

could decrease fixed cost and running cost in

DME synthesis process. Consequently, it might

decrease the whole production

Conclusion