NbhidNobuhide TAKAHASHI , TkT WADA IiIoriSHIMADA · Course, ShinshuUniveristy, Japan 1. CCS, CO2...

PCCC3, Regina, 8-9th Sep. 2015 N. Takahashi, Shinshu Univ. Japan

COCO22 desorption performance of aminedesorption performance of amine‐‐basedbasedCOCO22 desorption performance of aminedesorption performance of amine based based solvents by membrane flash processsolvents by membrane flash process

N b hid TAKAHASHI T k WADA I i SHIMADANobuhide TAKAHASHI, Takuya WADA, Iori SHIMADA and Hiroshi FUKUNAGA

Di i i f Ch i d M i l M i l d Ch i l E i i

ContentsContents

Division of Chemistry and Material, Materials and Chemical Engineering Course, Shinshu Univeristy, Japan

1. CCS, CO1. CCS, CO22 separation techniques and their tasksseparation techniques and their tasks22. Membrane flash process for absorbent regeneration . Membrane flash process for absorbent regeneration p gp gand objectives of this studyand objectives of this study

33. Experimental method of membrane flash process. Experimental method of membrane flash processp pp p4. Results of CO4. Results of CO22 desorption experiment and discussiondesorption experiment and discussion(Liquid permeation rate, CO(Liquid permeation rate, CO22 desorption rate, COdesorption rate, CO22 release ratio, release ratio, Energy requirement)Energy requirement)

5. Conclusion5. Conclusion


COCO22 separation techniques and separation techniques and isuuesisuuesp qp q

Physical absorption

For postFor post‐‐combustion capturecombustion capturey p

Adsorption

most practical for large‐scale sources emitting

Chemical absorption

Adsorption

Membrane separationflue gases with low CO2

concentration

CO2 capture plant for urea production in Malaysia using KEPCO/MHI process

IssuesIssues ofof CCSCCS usingusing chemicalchemical absorptionabsorption►►HighHigh capturecapture costcostgg pp►►LargeLarge energyenergy penaltypenalty

Present Target (2020) Target (2030)(METI, Japan, 2014)

Capture cost [yen/t‐CO2] 4,200 2,000 1,000

Energy requirement[GJ/t‐CO2] 4.0 1.5 1.0


COCO22 chemical absorptionchemical absorption‐‐ regeneration systemregeneration systempp g yg y

Purified gasCO2

RichRich

Flue

Reboiler

Flue gas

SteamLean

A ti l ti f th

Absorber Regenerator

ReboilerLean

A conventional regeneration of the absorbent by heating requireslarge quantity of heat energy !!large quantity of heat energy !!


A novel process of absorbent regenerationA novel process of absorbent regenerationp gp gMembrane flash process

K.Okabe,et.al.; International Journal of Greenhouse Gas Control 2,485-491(2008)

Reduced pressure AdvantagesAdvantages

CO2

CO

CO2 ・Low energy consumption・High CO2 concentration

gg

CO2CO2

Microporoushollow fiber ・Low CO desorption rate

Problems to be solvedProblems to be solved

Lean absorbent

Low CO2 desorption rate・Low CO2 release ratio

Rich absorbent


A novel process of absorbent regenerationA novel process of absorbent regenerationp gp gMembrane flash process

K.Okabe,et.al.; International Journal of Greenhouse Gas Control 2,485-491(2008)

Reduced pressure

►O ti diti

FactorsFactors influencinginfluencing desorptiondesorptionphenomenaphenomena

CO2

CO

CO2 ・Pressure・Temperature

►Operation condition

CO2CO2

Microporoushollow fiber

・Feed rate►Material

・Hollow fiber membraneLeanabsorbent

pore size, thickness,dimension, material

・Absorbent liquidRich absorbent

Objective of this study

・Absorbent liquidVLE, viscosity

Objective of this studyis to investigate CO2 desorption performance of various amine‐based absorbent in the membrane flash process.


◆Amine‐based absorbent◆Amine based absorbent

Absorbent FormulaActivated* hydrogen Hydroxyl

gro py gatom group

Monoethanolamine (MEA) H2NCH2CH2OH 2 1Diethanolamine (DEA) HN(CH CH OH) 1 2Diethanolamine (DEA) HN(CH2CH2OH)2 1 2Diisopropylamine(DIPA) (CH3)2CHNHCH(CH3)2 1 0N-methyldiethanolamine (MDEA) CH3N(CH2CH2OH)2 0 2y ( ) 3 ( 2 2 )2

*Hydrogen atom in amine groupShuiping Yan, et al., , Applied Energy, 98, 357‐367 (2012)

►4 M aqueous solution of each amine

►CO2 loading [mol‐CO2/mol‐amine] of rich solution

MEA 0.57DIPA 0.49 CO2 loading was set to the one equilibrating

i h CO i l f 1 k

2 g 2

DEA 0.53MDEA 0.35

with CO2 partial pressure of 15 kPa.


◆Membrane module◆► Porous hollow fiber membrane

Material : Polyethylene(PE)Pore diameter : 0.25 µmInner diameter : 0 7 mm

S i f i f

5µmInner diameter : 0.7 mmOuter diameter : 1.2 mm

SEM image of inner surface

Hollow fiber►Membrane module for Hollow fibermembrane

Number of fiber : 10

desorption experiment

65 mmNumber of fiber : 10Inner diameter of acrylic tube

: 20 mmEffective length : 65 mm

Acrylic tube


◆ CO2 desorption experiment2 p p►Experimental condition

Pressure difference [kPa] : 45-95(Atmospheric pressure: 96 kPa)

P

(Atmospheric pressure: 96 kPa)Flow rate of absorbent [ml/min] : 300 Temperature of Absorbent[C] : 70

T

循環ポンプ

Flowmeter

気体の流れ

液体の流れ

減圧ポンプリーン吸収液T

リチガクトグ

流量計

Gas flowLiquid flowPressure gaugeP

電子天秤リッチ吸収液

ガスクロマトグラフ

ThermometerT


◆ Evaluation of desorption performances)]/(m[m rate desorption CO 23

2

◆ p p►

][m fibers hollow of area surfaceOuter /s][m flowrate Gas[-] gas discharged in thecontent CO

2

32

10000αRαLαE

► CO2 release ratio

1001[%] ratio ReleaseR

LR

100

1000

10000

Pa]

solutionrichofloadingCO: 2R 0.1

1

10

P CO2[kP

1002[%] ratio ReleaseER

LR

COithiilib tl diCOamine]-/molCO-[mol

solution permeate of loading CO:amine]-/molCO-[mol

solutionrich ofloading CO:

22L

22R

0.0001

0.001

0.01

amine]-/molCO-[mol pressure reducedunder pressure partial COwith ingequilibratloading CO:

2

22E0.0001

0 0.2 0.4 0.6 0.8 1CO2 loading [mol‐CO2/mol‐amine]


◆ Liquid permeation rate◆ q p

100

1201

05 MEADEA

Ab b Viscosity

60

80

atio

nra

te

m2 ･

s)]

DIPAMDEA

Absorbent Viscosity[mPa･s]

MEA 0.71DEA 1 6

40

60

idpe

rmea

[m3 /(

m DEA 1.6DIPA 1.9

MDEA 3.0

0

20

Liqu

i

(4M, 70C)

40 60 80 100Pressure difference [kPa]

Increase in pressure differenceIncrease in liquid permeation rate

MEA > DEA > DIPA > MDEAMEA > DEA > DIPA > MDEAIncrease in viscosity Decrease in liquid permeation rate


◆ CO2 desorption rate◆ 2 p

40004500

6 MDEA

250030003500

nra

te1

06

m2 ･

s)]

DEADIPAMEA

150020002500

Des

orpt

ion

[m3 /(

m MEA

0500

1000D

040 60 80 100

Pressure difference [kPa]

d ff dIncrease in pressure differenceIncrease in CO2 desorption rate Pressure difference > 90 kPa

= absolute pressure < saturated vapor pressureabsolute pressure < saturated vapor pressure Intensive vapor generation caused significant reduction in

CO2 partial pressure


◆ CO2 desorption rate◆ 2 p

40004500

6 MDEA

250030003500

nra

te1

06

m2 ･

s)]

DEADIPAMEA

150020002500

Des

orpt

ion

[m3 /(

m MEA

0500

1000D

040 60 80 100


MDEA > DEA > DIPA > MEA


◆ CO2 desorption rate2 pActivatedhydrogen

atomHydroxyl

group40004500

06

： 0 2

： 1 2250030003500

onra

te1

0(m

2 ･s)

] MDEA

DEA ： 1 2

： 1 0100015002000500

Des

orpt

io[m

3 /( DEA

DIPA

： 2 10

5001000

MEA


For the primary and secondary amines, decrease in activated hydrogen causes

RR’NCOO + H2O ↔ RR’NH + HCO3 (1)

p y y , y greduction in basicity of absorbent and stability of carbamate, resulting in lesscarbamate and more bicarbonate.

RR NCOO H2O RR NH HCO3

CO2 + H2O ↔ H+ + HCO3

( )

(2)Bicarbonate is easily decomposed by heating, resulting in more CO2.


◆ CO2 desorption rate2 pActivatedhydrogen

atomHydroxyl

group40004500

06

： 0 2

： 1 2250030003500

onra

te1

0(m

2 ･s)

] MDEA

DEA ： 1 2

： 1 0100015002000500

Des

orpt

io[m

3 /( DEA

DIPA

： 2 10

5001000

MEA


The steric hindrance effect due to hydroxyl group reduces the stability ofy y g p ycarbamete and accelerates the hydrolysis of carbamate to produce more bicarbonate ion. As a result, CO2 is more easily released for DEA.

O-

NCH2CH2OHCH2CH2OH + H2O↔ RR’NH + HCO3

- (3)O CO-


◆ CO2 desorption mechanism◆ 2 pLiquiddroplet

Reduced

CO2

CO

1) Desorption from surfaces ofpermeated absorbent liquid

pressure CO2

CO2

2) Desorption from surfaces ofmembrane pores

bGas phase Liquid phase

Rich solutionFallingdown

2

MembraneGas phase(shell side)

Liquid phase(tube side)


Influences of pore size of membrane

200

Liquid permeation rate

2500

CO2 desorption rate

p

(4M DEA(40C))(4M DEA(40C))

120140160180

rate1

05

･s)]

0.1µm0.25µm

1500

2000

ate

106

･s)]

0.1 µm0.25 µm

6080100120

ermeatio

n r

[m3 /(

m2

1000

1500

esorption ra

[m3 /(m

2 ･

02040

40 60 80 100

Pe

0

500De



Low permeation ll High desorption

Small pore size Low liquid permeation

Small pore size Low permeationrate

Small pore size High desorptionrate

Long contact time and large contact areabetween liquid and membrane Promotion of CO2 desorption



Reduced

CO2

CO


pressure CO2

CO2




2



CO2 desorption rate: MDEA > DEA > DIPA > MEA

Lower liquid permeation rate

CO2 desorption rate: MDEA > DEA > DIPA > MEA Liquid permeation rate: MDEA < DEA < DIPA < MEA

Lower liquid permeation rate→ Longer contact time between liquid and pore surface

→ PromotionPromotion ofof COCO22 desorptiondesorption inin porespores


◆ CO2 release ratio◆ 2

25MDEA

25MDEA

ReleaseRelease ratioratio 11 ReleaseRelease ratioratio 22

15

20

o 2

[%]

MDEADEADIPA

15

20

o 1

[%]

MDEADEADIPA

10

15

leas

e ra

tio MEA

10

15

leas

e ra

tio MEA

0

5Rel

0

5Rel

i h d i li id i

040 60 80 100

Presure difference [kPa]

040 60 80 100

Presure difference [kPa]

Higher CO2 desorption rate + Lower liquid permeation rate

MuchMuch higherhigher COCO releaserelease ratioratio

MDEA is most suitable for membrane flash process

MuchMuch higherhigher COCO22 releaserelease ratioratio


◆ Evaluation of energy requirement for CO2 desorption►Energy of vacuum pump, Ev[kJ/s] qg [m3/s]：gas flowrate (measured value)

Ps [kPa] ：suction pressurePd [kPa] ：discharge pressure = Patm NPPPNE 11

sd

2

Pd [kPa] ：discharge pressure PatmN [-] ：compression stage number = 1.0 ηEA [-] ：adiabatic coefficient of compression

＝0.8

EAqPE

1

sdgsv

►Energy for liquid feed, Ef [kJ/s]γ [-]：specific heat ratio＝1.3 (CO2)

gy q , f [ ]

Ef = Pf QLPf [kPa] ：pressure drop in the hollow

fibers when the liquid flows►Heating energy of liquid, Eh [kJ/s]

C [kJ/(m3 K)] ：heat capacity of the liquid

fibers when the liquid flowsQL [m3/s] :liquid feed rate to the module

=1.1 actual liquid permeation rate►Reaction heat E [kJ/s]

eat g e e gy o qu d, h [ J/s]

Eh=CpT QL

Er=H QCO2

Cp [kJ/(m3 K)] ：heat capacity of the liquidT [K] ：temperature increase = 7025

►T t l i t E [kJ/ ]

►Reaction heat, Er [kJ/s]

H [kJ/mol-CO2] ：heat of reaction►Total energy requirement, E [kJ/s]

E = (Ev + Ef )/+ Er + Eh

[ 2]QCO2 [mol/s] ：CO2 desorption rate

η [-] ： thermal efficiency of power generation=0 40=0.40

Finally, the total energy requirement, Ewas divide by CO2 desorption rate toobtain energy requirement per unit mass of CO2 released.


◆ Energy requirement for CO2 desorptiongy q 2 p

30

ent 30

entMEA DEA

Reaction heatHeatingVacuumLiquid feed

152025

requ

irem

eJ/ｔ-

CO

2]152025

requ

irem

eJ/ｔ-

CO

2]

MEA DEA

05

10

Ener

gy [GJ

05

10

Ener

gy [GJ

040 65 85 95


040 65 85 95


30 30

202530

quire

men

t-C

O2]

202530

quire

men

t-C

O2]

DIPA MDEA

51015

Ener

gyre

q[G

J/ｔ-

51015

Ener

gyre

q[G

J/ｔ-

040 65 85 95


040 65 85 95



◆ Energy requirement for CO2 desorption(no air leak‐in)

5

nt

5

nt

gy q 2 p ( )

MEA DEA

Reaction heatHeatingVacuumLiquid feed

3

4re

quire

men

J/ｔ-

CO

2]3

4

requ

irem

enJ/ｔ-

CO

2]

MEA DEA

1

2

Ener

gyr

[GJ

0

1

2

Ener

gy [GJ

040 65 85 95


040 65 85 95


5 5

3

4

5

quire

men

t-C

O2]

3

4

5

quire

men

t-C

O2]

DIPA MDEA

1

2

Ener

gyre

q[G

J/ｔ-

1

2

Ener

gyre

q[G

J/ｔ-

040 65 85 95


040 65 85 95



ConclusionF diff i l i (MEA DEA DIPA MDEA)Four different amine solutions (MEA, DEA, DIPA, MDEA) weretested to find an absorbent suitable for the membrane flashprocess for absorbent regenerationprocess for absorbent regeneration.

MDEA had the lowest permeation rate and the highest CO2desorption rate On the contrary MEA had the highest permeationdesorption rate. On the contrary, MEA had the highest permeationrate but the lowest CO2 desorption rate. DEA and DIPA hadmoderate permeation and CO2 desorption rates, but both ratesp 2 p ,were slightly higher for DEA than for DIPA.

From these results, it has been concluded that MDEA was most,suitable for the membrane flash process among the absorbentsused in this study.

Thank you very much for your attentionThank you very much for your attention



Reduced

CO2

CO


pressure CO2

CO2




2

According to the first mechanism, MEA might have shown the highest



g , g gdesorption rate because the falling speed of droplets and gas‐liquid contactarea per unit time were the greatest.

ThisThis isis notnot truetrue ofof thethe experimentalexperimental resultsresultsThisThis isis notnot truetrue ofof thethe experimentalexperimental resultsresultsInfluences of chemical structure of absorbenton the reaction between CO2 and amines


Comparison between cases with and without liquid permeation

Reducedpressure

Reducedpressure

Richsolution

Richsolution



solution



Without liquid permeationWith liquid permeation


Comparison between cases with and without liquid permeation

4500

300035004000

te1

06

s)] CO2

With permeationWithout permeation

150020002500

orption rat

[m3 /(m

2 ･s

Reducedpressure

050010001500

Deso[

Richsolution

040 60 80 100




L t t b t li id d

With liquid permeation > Without liquid permeation

►Large contact area between liquid and gas

►Promotion of CO2 desorption by contact between liquid and membrane


Influences of liquid flow rate on CO2 desorption rate With liquid permeation

q 2 pWithout liquid permeation

(4MMDEA) (4MMDEA)

1500

2000

106

300ml/min62ml/min34 l/ i

1500

2000

106

0.1µm 300ml/min0.1µm 150ml/min0 1 34 l/ i

(4M MDEA) (4M MDEA)

1000

tionrate1

m3 /(m

2 ･s)] 34ml/min

400ml/min150ml/min1000

tion rate

m3 /(m

2 ･s)] 0.1µm 34ml/min

500Desop [m

500

Desorpt

[m

040 60 80 100


040 60 80 100

Pressure difference[kPa]

Increase in flow rate

Increase indesorption rateNo clear effect flow rate desorption rate

PCCC3, Regina, 8-9th Sep. 2015 N. Takahashi, Shinshu Univ. Japan結果と考察

nHが減少すると吸収液の塩基性が低下しカルバミン酸塩が不安定になり、解離する

2'2 CONHRR

(8)式よりカルバミン酸塩の減少に反比例し、 Kcarbは増加する

22 CONHRR

また、(5)式より、カルバミン酸塩が減少するとアミンが生成される

(9)式より、アミンが生成に比例しKAMが増加する

(11)式より、KAMとKcarbの増加によりKOVが減少する

KOVが減少すると(4)式の反応が逆に進みCO2が放散される

PCCC3, Regina, 8-9th Sep. 2015 N. Takahashi, Shinshu Univ. Japan～MEAとDEAの平衡論から予想する放散性能の比較～結果と考察

気液衡デグ気液衡デグ

1000

10000

MEAaqの気液平衡ローディング

1000

10000

DEAaqの気液平衡ローディング

1

10

100

P CO2[kPa]

1

10

100

P CO2[kPa]

95kPa

0.01

0.1

15M MEA 40

0.01

0.1

1P

4M DEA 4095kPa

0.0001

0.001

0 0.2 0.4 0.6 0.8 1 1.2CO2 loading [mol‐CO2/mol‐amine]

投入ローディング

0.0001

0.001

0 0.2 0.4 0.6 0.8 1 1.2CO2 loading [mol‐CO2/mol‐amine]

投入ローディング

CO2 loading [mol CO2/mol amine]

DEAはMEAに比べて気相中CO2分圧変化に対する

CO2 loading [mol CO2/mol amine]※(水蒸気分圧は考慮しない)

2液中平衡ローディング変化が大きい

減圧放散プロセスにより適す


◆Amine‐based absorbent

Absorbent FormulaActivatedhydrogen Hydroxyl

◆Amine based absorbent

Absorbent Formula hydrogenatom group

Monoethanolamine (MEA) H2NCH2CH2OH 2 1Di h l i (DEA) HN(CH CH OH) 1 2Diethanolamine (DEA) HN(CH2CH2OH)2 1 2Diisopropylamine(DIPA) (CH3)2CHNHCH(CH3)2 1 0N-methyldiethanolamine (MDEA) CH N(CH CH OH) 0 2N-methyldiethanolamine (MDEA) CH3N(CH2CH2OH)2 0 2

Activated hydrogen atom*ex.) DEA

= Hydrogen atom in amine groupInfluence on reaction equilibrium and

kinetics with CO2kinetics with CO2

Hydroxyl group Influence on water‐solubility, vapor pressure

*Shuiping Yan, et al., , Applied Energy, 98, 357‐367 (2012)


Specifications of hollow fiber membranes andSpecifications of hollow fiber membranes and modulesmodules

Membrane namePore

diameterMembranethickness

Innerdiameter

Outerdiameter Porosity

[m] [mm] [mm] [mm] [%][m] [mm] [mm] [mm] [%]MF* (0.1 m) 0.1*** 1.75 6.7 10.0 33-37****MF *(0.2 m) 0.2*** 1.75 6.7 10.0 33-37****MF* (0 5 m) 0 5*** 1 75 6 7 10 0 33 37****MF* (0.5 m) 0.5*** 1.75 6.7 10.0 33-37****FB**(thin) 0.39 1.5 10.7 13.7 37FB**(thick) 0.41 2.5 8.6 13.6 39

* Commercial microfiltration membrane ** Fabricated membrane*** Pore diameter estimated from molecular weight cut off ****Porosity of the substrate

●Membrane module for CO2 desorption experiment

Effective

●Membrane module for CO2 desorption experimentPorous hollowfiber membrane

Effectivelength:65 mm

Branchtube

i.d. 27 mmAcrylictube


LLiquidiquid permeationpermeation raterate

3

] 薄膜FB (thin)20

)] 0.5µm(市販)MF (0 1m)

Effects of pore size Effects of thickness

2

2.5

m3 /(

m2 ・

s) 薄膜

厚膜

FB (thin)FB (thick)

15

m3 /(

m2 ・

s) 0.5µm(市販)0.2µm(市販)0.1µm(市販)

MF (0.1m)MF (0.2m)MF (0.5m)

1.5

2

ate

[10-5

m

10

ate

[10-5

m

0 5

1

mea

tion

ra

5

mea

tion

ra

0

0.5

40 50 60 70 80 90 100Pe

rm

040 50 60 70 80 90 100

Perm

40 50 60 70 80 90 100Pressure difference [kPa]

40 50 60 70 80 90 100Pressure difference [kPa]

Pore size increase Membrane thickness increase

Permeation rate increase Permeation rate decrease


COCO22 desorptiondesorption raterate (Effects(Effects ofof membranemembrane thickness)thickness)

160180200

(m2 ・

s)]

厚膜

薄膜

FB (thick)FB (thin)

Membrane Pore Membrane

100120140

[10-6

m3 /( 0.1µm(市販)

0.2µm(市販)0 5µm(市販)

MF (0.1m)MF (0.2m)MF (0 5m)

Membrane name diameter thickness

[m] [mm]MF (0.1 m) 0.1 1.75(0.05*)

6080

100

ion

rate

[ 0.5µm(市販)MF (0.5m) MF (0.1 m) 0.1 1.75(0.05 )MF (0.2 m) 0.2 1.75(0.05*)MF (0.5 m) 0.5 1.75(0.05*)FB (thin) 0 39 1 5

02040

Des

orpt

i FB (thin) 0.39 1.5FB (thick) 0.41 2.5

* Thickness of pore size controlling layer040 50 60 70 80 90 100


M b hi k i C iMembrane thickness increaseEnhancement of CO2 desorption

Contact area increase

Trade offLiquid permeation rate decrease Decrease in opportunity of contact

between the liquid and membrane

Trade-off

NbhidNobuhide TAKAHASHI , TkT WADA IiIoriSHIMADA · Course, ShinshuUniveristy, Japan 1. CCS, CO2...

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Transcript of NbhidNobuhide TAKAHASHI , TkT WADA IiIoriSHIMADA · Course, ShinshuUniveristy, Japan 1. CCS, CO2...