AIChE Annual Meeting 2014 - MTO Backend

Laboratory for Chemical Technology, Ghent University

http://www.lct.UGent.be

Energy Efficient Light Olefin Recovery:Absorption Versus Cryogenic Distillation

Pieter A. Reyniers, João F. dos Santos, Stephanie SaerensPieter Cnudde, Laurien A. Vandewalle, Thomas M. Deconinck

Steven J. Govaert, Philip de Smedt, Kevin M. Van GeemGuy B. Marin

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14AIChE Annual Meeting, Atlanta, GA, USA, 17/11/2014

Increasing propene demand

Gap between propene supply and demand is filled by production from on-purpose

routes such as propane dehydrogenation, metathesis and methanol to olefins

2


CB&I Investor / Analyst Day 2011. http://sec.edgar-online.com/chicago-bridge-iron-co-n-v/8-k-current-report-filing/2011/11/09/section6.aspx

On-purpose propene gap

Methanol to olefins (MTO)

Developed by UOP and Norsk Hydro A.S.

SAPO-34 catalyst operated in continuous regenerations

Combined ethene and propene yield of 75-80 wt% on feed carbon

3


Senetar, J. J.; Romers, E., Scale-Up Of Advanced MTO Technology And Integrated OCP Technology. In AIChE Spring National Meeting, Chicago, IL, USA, 2011.

New perspectives due to MTO

Methanol to olefins clears the path for alternative separation designs

due to low light ends content (CH4, CO, H2, N2) in the reactor effluent

Engineering develops and implements this technology

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Li, L.; Ni, J. A non-cryogenic separation method for lower hydrocarbon containing light gas. WO 2009012623 A1, 2009.

Wison commercializes new methanol-to-olefins technology in China. Hydrocarbon Processing 2013.

Harris, P., UOP announces China downstream achievements. Oil & Gas Technology 23/06/2014.

Patent WO 2009/012623 A1

January 2009

Start-up of full scale plant*

September 2013

163 kt of light olefins

June 2014

* Design capacity: 300 kta light olefins

Separation section as a black box

Component wt% Component wt%

N2 0.40 BUTANE 1.01

H2 0.49 BUTENE 8.53

CO 0.49 2ME-PROPANE 0.25

CH4 0.59 2ME-PROPENE 2.27

ETHYNE 0.01 1,3-BUTADIENE 0.54

ETHENE 33.89 PENTANE 0.42

ETHANE 0.39 PENTENE 3.76

PROPYNE 0.05 2ME-BUTANE 0.10

PROPADIENE 0.05 2ME-BUTENE 0.94

PROPENE 45.12 DME 0.20

PROPANE 0.49

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http://www.marler-zeitung.de/storage/pic/xmlios/zbm-import/aus-der-region/92300_1_xio-fcmsimage-20091010221603-006008-4ad0eb834d1d2.210_008_334982_Pol_Chemiep.jpg?version=1302271767

Model feed composition

19 bara, 40 °C

150 t/h - P/E = 1.5

Product specifications

Product T [°C] P [barg] Rec [%] Purity [wt%]

FUEL GAS 30 5 - -

ETHENE 30 20 99.50 99.95

ETHANE 30 5 - -

PROPENE 40 15 99.50 99.60

PROPANE 40 15 - -

C4+ 40 10 - -

Low pressure steam 6 bara

Cooling water ΔT = 15 °C

Closed loop propene refrigeration cycle

(Closed loop ethene refrigeration cycle)

Demethanizer first configuration

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Demethanizer first scheme as most energy efficient cryogenic

configuration

ETHENE

ETHANE

PROPENE

PROPANE

C4+

FEED

FUEL GAS

DEMETHANIZER

DEETHANIZER

DEPROPANIZER

C2-SPLITTER

C3-SPLITTER

COLD BOX

100

90

80

70

60

50

40

30

20

10

0

-10

-20

-30

-40

-50

-60

-70

-80

-90

-100

Temperature [°C]

Van Geem, K. M.; Marin, G. B.; Hedebouin, N.; Grootjans, J., Energy efficiency of the cold train of an ethylene cracker. Oil Gas-Eur. Mag. 2008, 34, (2), 95-99.


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Demethanizer first scheme as most energy efficient cryogenic

configuration

ETHENE

ETHANE

PROPENE

PROPANE

C4+

FEED

FUEL GAS

DEMETHANIZER

DEETHANIZER

DEPROPANIZER

C2-SPLITTER

C3-SPLITTER

COLD BOX

100

90

80

70

60

50

40

30

20

10

0

-10

-20

-30

-40

-50

-60

-70

-80

-90

-100

Temperature [°C]

Van Geem, K. M.; Marin, G. B.; Hedebouin, N.; Grootjans, J., Energy efficiency of the cold train of an ethylene cracker. Oil Gas-Eur. Mag. 2008, 34, (2), 95-99.

Absorption configuration

FEED

FUEL GAS

PROPENE

PROPANE

C4+

ETHENE

ETHANE

HP-DEPROPANIZER

LP-DEPROPANIZER

PRECUTTER

ABSORBER

DEETHANIZER

C2-SPLITTER

C3-SPLITTER

COLD BOX 1

COLD BOX 2

100

90

80

70

60

50

40

30

20

10

0

-10

-20

-30

-40

-50

-60

-70

-80

-90

-100

Temperature [°C]

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“Pre-cutting and oil absorption” technology by Engineering



FEED

FUEL GAS

PROPENE

PROPANE

C4+

ETHENE

ETHANE

HP-DEPROPANIZER

LP-DEPROPANIZER

PRECUTTER

ABSORBER

DEETHANIZER

C2-SPLITTER

C3-SPLITTER

COLD BOX 1

COLD BOX 2

100

90

80

70

60

50

40

30

20

10

0

-10

-20

-30

-40

-50

-60

-70

-80

-90

-100

Temperature [°C]

9


“Pre-cutting and oil absorption” technology by Engineering

Overall higher temperatures compared to demethanizer first configuration


Closed propene and ethene cycles to generate cooling duty at multiple

cryogenic temperature levels

Refrigeration section

C3R1

PROPENE CYCLE

C3R2

C3R0COOLING

WATER

C3R3

C3R4C3R4'

C2R1

ETHENE CYCLE

C2R2

C2R0

C2R3

K-31K-32K-33K-34

K-21K-22K-23

X1X2X3X4

X5X6

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mC3H6

mC2H4

Process duties mC3H6, mC2H4, X1..X6 m𝑐𝑜𝑜𝑙𝑖𝑛𝑔 𝑤𝑎𝑡𝑒𝑟, Pcompressors

Method for techno-economic analysis

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Energy and material balances from process simulations in Aspen Plus V7.3

Pinch analysis

Feed sensitivity

Operational

expenditure

Capital

expenditure

Economic KPI

NPV, IRR, DPBT

Utility consumption

Maintenance

cost

Project

completion [%]

Technological

Economic

Variations on feed composition provide an indication of stability

Demethanizer first configuration is more stable than absorption configuration

CH4 has the highest effect on ethene purity in absorption configuration

Feed sensitivity

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Pinch analysis –composite curves

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Minimum hot and cold utility duty is comparable for the two configurations

Difference in terms of heat integration potential is minor

Kemp, I. C., Pinch Analysis and Process Integration: A User Guide on Process Integration for the Efficient Use of Energy. Elsevier Science: 2011.

Pinch analysis – grand composite curve

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Minimum hot and cold utility duty is comparable for the two configurations

Difference in terms of heat integration potential is minor

Kemp, I. C., Pinch Analysis and Process Integration: A User Guide on Process Integration for the Efficient Use of Energy. Elsevier Science: 2011.

Icarus Cost Estimator

ISBL capital expenditure

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Peters, M. S.; Timmerhaus, K. D., Plant design and economics for chemical engineers. McGraw-Hill: 1991.

Total capital investment (TCI)

Fixed capital investment Working capital

Total direct cost Total indirect cost

Total installed cost

Total purchased equipment cost

Land

Engineering Contractors Contingency

Auxiliary Facilities

Installation E&I Piping

275 % of TPEC

275 % of TPEC

385 % of TPEC

462 % of TPEC

Total purchased equipment cost (TPEC) for the absorption configuration is

2.2 106 $ lower than TPEC demethanizer first configuration

- Lower cost for distillation columns and refrigeration

- Heat exchangers and vessels are more expensive

Difference of 10.3 106 $ in total capital investment

Capital expenditure

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Operational expenditure

All mechanical energy is delivered by electromotors

All thermal energy is delivered via steam generated from natural gas

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Maintenance Mechanical energy Thermal energy

Pumps Compressors Steam

Process Refrigeration

∆ = 0.19 106 $/y

Economic key performance indicators

Small difference in total capital investment and operational expenditure

Product price 1263 $/t

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Product Price [$/t] Wt% Ref.

Fuel gas 155.91 0.83 (1)

Ethene 1404.00 34.15 (2)

Ethane 423.56 0.51 (1)

Propene 1330.00 45.63 (3)

Propane 616.11 0.92 (1)

C4+ 934.07 17.95 (4)

Total 1263.21 100.00

(1) Natural gas price scaled with net heating value

(2) Platts Global Ethylene Price Index

(3) Platts Global Propylene Price Index

(4) Conventional Gasoline Spot Price for U.S. Gulf Coast

(a) Methanol Spot Price North America (Methanex)

Feedstock cost 500 $/t

Methanol price 482 $/t (a)

Cost contribution from MTO

reaction section is minimal

Economic key performance indicators

Small difference in total capital investment and operational expenditure

Construction: 1 year Operation: 20 years

Product price 1263 $/t Feedstock cost 500 $/t

Raw material cost and product revenues are dominant over operational

expenditure and depreciation costs

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Key performance indicator Demethanizer Absorber

Total capital investment (TCI) 106 $ 293.08 282.83

Operational expenditure 106 $/y 42.08 41.89

Net present value (15% discount rate) 106 $ 345.07 355.25

Internal Rate of Return % 30.85 31.85

Discounted Payback Time y 6.27 6.03

Feed light ends content

A lower light ends content (CH4, CO, H2, N2) in the feed is favorable for

the absorption configuration and unfavorable for the demethanizer first

configuration

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Effect of lower light ends content Demethanizer Absorber

Light ends sensitivity ≈ ↓

Pinch potential ≈ ↓

Total capital investment (TCI) ↑ ↓

Operational expenditure ↑ ↓

Net present value ↓ ↑

Conclusions

Comparison of two alternative configurations of a methanol to olefins

back-end section, specifically tuned for streams with low light ends


Higher stability towards variations in the light ends (CH4, CO, H2, N2) content

Lower hot and cold utility usage upon full heat integration (∆ ≈ 1 MW)


Lower overall operational expenditure due to lower steam demand but higher

mechanical energy demand (∆ = 0.19 106 $/y)

Lower total purchased equipment cost due to cheaper distillation columns and

smaller refrigeration section (∆ = 2.20 106 $)

Higher Net Present Value (∆ = 10.18 106 $)

A lower light ends content is favorable for the absorption configuration

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Acknowledgements

Fund for Scientific Research Flanders (FWO).

The Long Term Structural Methusalem Funding

IWT-SBO: Bioleum

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BIOLEUMBiomass conversion

Laboratory for Chemical Technology, Ghent University

http://www.lct.UGent.be

Energy Efficient Light Olefin Recovery:Absorption Versus Cryogenic Distillation

Pieter A. Reyniers, João F. dos Santos, Stephanie SaerensPieter Cnudde, Laurien A. Vandewalle, Thomas M. Deconinck

Steven J. Govaert, Philip de Smedt, Kevin M. Van GeemGuy B. Marin

23


Documents

AIChE Annual Meeting 2014 - MTO Backend