Process Intensification: a key to synthetic carbon-based fuels

Enrico Tronconiwith Gianpiero Groppi, Carlo G. Visconti, Alessandra Beretta, Luca Lietti, Matteo

Maestri, Matteo Ambrosetti, Mauro Bracconi, Riccardo Balzarotti, Laura Fratalocchi

Dipartimento di Energia, Politecnico di Milano, Milano (Italy)

November 12th, 2020

Intensifying heat transfer in multitubular catalytic reactors

EU Patent 1 110 605 B1; US Patent 7,678,342

ERC Advanced Grant 2015 Action 694910: INTENT

“Structured Reactors with INTensified ENergyTransfer for Breakthrough Catalytic Technologies”

From a slow convective mechanismto fast heat conduction in the solid matrix

G. Groppi & E. Tronconi, Chem. Eng. Sci. 55 (2000) 2161E. Tronconi et al., Curr. Opinion Chem. Eng. 5 (2014) 55

Tronconi, Groppi, Visconti, Curr. Opinion Chem. Eng. 5 (2014) 55

Flow independent

Flow dependent

a) b) c) d)

OutlineConcept: conductive structured catalysts in heat transfer-limited processes for energy vectors

Fischer-Tropsch synthesis:• conductive honeycombs• conductive open-cell foams• conductive Periodic Open Cellular Structures (POCS)

Methane Steam Reforming:• conductive open-cell foams• conductive Periodic Open Cellular Structures (POCS)

Packed bed Honeycomb Foam POCS

1. Conductive structured catalysts for the Fischer-Tropsch Synthesis: honeycombs

Sasol, Oryx GTL (Qatar) 17000 BPD/reactor Shell, Pearl GTL (Qatar) 5833 BPD/reactor

Associated gas and stranded oil

Market analysis reveals over 800 oil fields globally, onshore and offshore, where associated gas is problematic,

and conditions suit a modular GtLsolution.

There is an estimated total of over 73Bn bbls of crude reserves across these assets.

Gas flaring in Nigeria

GTL = Gas-To-Liquids

180-280ºC5-30 bar

Catalyst

CnH2n+2

CnH2n

CnH2n+1OH

H2O , CO2

CO + H2

and jet fuel…

BTL = Biomass-To-Liquids

www.fischer-tropsch.org

Sasol, Oryx GTL (Qatar) 17000 BPD/reactor Shell, Pearl GTL (Qatar) 5833 BPD/reactor

Scaling down

Technologically feasible Economically sustainable

Modular, eggshell catalystsbut...thermally unmanageable on

a small-scale

Isothermal, no intraporous resistancesbut...not modular and not suitable for

small-scale units

Gas to Liquid (GtL) Processes: Fischer-Tropsch reactors

Scaling down

Technologically unfeasible Economically unsustainable

Heat removal is critical in FTS

The FTS is highly exothermal (∆H0R ≅ −165 kJ/molCO), an inefficient T-control would lead to:

Drop of the selectivity Fast catalyst deactivation Thermal runaway of the reactor

• Hot-spots • Strong axial and radial T-gradients

Improved Heat Transfer is crucial

How to manage the heat removal in compact MTPBRs?

The FTS is highly exothermal (∆H0R ≅ −165 kJ/molCO), an inefficient T-control would lead to:

Drop of the selectivity Fast catalyst deactivation Thermal runaway of the reactor

• Hot-spots • Strong axial and radial T-gradients

Improved Heat Transfer is crucial:

K. Pangarkar, T. J. Schildhauer, J. R. van Ommen, J. Nijenhuis, J.A. Moulijn, F. Kapteijn, Cat. Today 147S (2009) S2-S9.

“Solving the Heat Transport Issue in FTS Fixed-Bed Reactors with Structured Catalysts”

Al foamε = 0.90

Knitted wireε = 0.90

OCFSε = 0.84

CCFSε = 0.95

Honeycombs

Development of a washcoating procedure

Selection of materials

Chem. Eng. J. 171 (2011) 1294

Lab-scale catalysttesting (at PoliMi’s site)

Industrial reactor modeling

Appl. Catal. A 370 (2009) 93Appl. Catal. A 370 (2009) 93

PHAS

E 1

PHAS

E 2

Design & manufacturing of improved materials

Lab-scale catalysttesting (at PoliMi’s site)

Pilot-scale testing (at Eni’s site)

Demo scale reactor design

WO/2010/130399 WO/2014/102350

Conductive monoliths for FTS in small-scale MT-FBRs?

p

p

p

p

Washcoated monolith

channels

PROs• Higher catalyst inventory

CONs• Higher pressure drop• (Longer diffusion lengths)

p

p

p

p

Monolith channels packed with small catalyst pellets

How to increase the “activity in the reactor”:“Packed monolith” concept

US Patent 9,387,456

Pilot-scale testing @ Eni

packed honeycomb

monolith28mm

syngas

products

Tube ID28 mm

thermocouplethermowell

dch= 4 mm

~300 gcat, dp=300 µm

An example of data collected in the FTS pilot reactor

P0=25 bar, H2/CO=2.1

∆P < 1 bar

Outstanding heat transfer performance of a compact reactor (1 m long tube):

U ≈ 1.5 kW/m2/K

2. Conductive open-cell foams: application to the Fischer-Tropsch synthesis

NASA Space Center, Houston (TX):

Foam sandwich as protective shieldfor aerospace applications

Honeycomb vs. Foam!

Conductive Metallic Foams for the FTS

Conductive structured catalysts

G. Groppi & E. Tronconi, Chem. Eng. Sci. 55 (2000) 2161E. Tronconi et al., Curr. Opinion Chem. Eng. 5 (2014) 55 Monoliths, micromonoliths, foams, POCS, microchannel blocks...

Almeida et al. Cat. Today 215(2013)103 ISSUES OF WASHCOATED FOAMS: • the overall load of catalytically active phase is much less (20-25

vol.%) than in a bed of bulk pellets (65 vol.%) (thin catalyst layer, high void fraction)

• improved washcoating techniques are needed: the macropores of the foam may be partially clogged

From slow convective mechanism to the fast heat conduction in the solid matrix

Improved Heat Transfer

40 ppi 20 ppiεfoam= 0.886 εfoam= 0.885

Packed open-cell foam catalysts for FTS

Al-foams packed with Co/Pt/Al2O3 catalyst

Foams acquired from ERG Aerospace, USA

US Patent 9,890,333

Heat transfer measurements:C.G. Visconti et al., Cat. Today 273 (2016) 178–186

dp = 300 µm

Catalyst activity: Packed-foam reactorP= 25 bar, H2/COin= 2 mol/mol, GHSV= 6410 cm3(STP)/h/gcat, inerts= 24 vol.%. T = 180-240°C

• Catalyst active even at low T:ΧCO= 12.1% @195°C; ΧCO= 16.5% @200°C

• Catalyst reaches high CO conversions(55-67 % @230-240°C)

• Catalyst does not deactivate even after 800 h of T.o.S.

Fratalocchi et al., Chem. Eng. J. 349 (2018) 829-837Fratalocchi et al., RC & Eng.ng, 4 (2019) 1917-1921

Catalyst activity: Packed-bed reactorP= 25 bar, H2/COin= 2 mol/mol, GHSV= 6410 cm3(STP)/h/gcat, inerts= 24 vol.%. T = 180-240°C

• Catalyst active even at low T (ΧCO= 12.1% @195°C; ΧCO= 16.5% @200°C)

• Catalyst reaches high values of CO conversion (55-67 % @230-240°C)

• Catalyst does not deactivate even after 800 h of T.o.S.

18 20 22 24 26 28150

160

170

180

190

200

210

220

230

240 packed-bed packed-foam

Tcat

[°C]

time [h]

Runaway during the T-ramp from 190 to 195°C

Fratalocchi et al., Chem. Eng. J. 349 (2018) 829-837

T-Profiles along the catalyst bed: Packed-foam reactor

Tcat [°C] XCO[%]

Q[kW/m3]

∆Tcat[°C]

180 4 80.61 0.2

190 8 161.23 0.5

195 12 243.86 1

200 16.5 332.53 0.9

205 22 427.25 1.2

210 28 566.31 2.1

215 33.4 675.14 3.3

220 44 900.86 3.8

225 50 1013.71 4.5

230 54.5 1098.36 5.4

240 67.5 1360.35 6.4

𝑄𝑄 𝑘𝑘𝑊𝑊/𝑚𝑚3 =−∆𝐻𝐻𝑅𝑅0 � 𝐹𝐹𝐶𝐶𝐶𝐶𝑖𝑖𝑖𝑖 � 𝑋𝑋𝐶𝐶𝐶𝐶

𝑉𝑉𝑐𝑐𝑐𝑐𝑐𝑐

1.0 1.5 2.0 2.5 3.0175180185190195200205210215220225230235240245250

180 190 195 200 205 210 215 220 225 230 240

Tcat

[°C]

Catalyst bed [cm]

3. Conductive Periodic Open Cellular Structures (POCS) for the FTS

0 200 400 600 800 1000 1200 1400 1600 1800 200002468

101214161820222426

packed-FOAMpacked-POCS packed-POCS (with the skin)

∆Tex

t [°C

]

Q [kW/m3]

POCS from METAMAT-lab @ PoliMI

3D printing of different cell geometries in Aluminium

TKKD CELL DIAMOND CELL CUBIC CELL

Prof. Stefano Beretta

Packed-POCS with metallic skin for FTS

εpocs≈ 0.890; dcell≈ 3 mm (diamond cell) made by 3D printing (AlSi7Mg0.6)

PackedFoam

PackedPOCS

PackedPOCS(skin)

Catalyst weight [g] 7.2 7.2 7.2

Catalyst volumetricdensity [g/cm3] 0.63 0.63 0.69

Cata

lyst

2 cm

α-A

l 2O3

1.1

cmα

-Al 2O

31.

1 cm

TaxTrad Text

L= 4

.2 c

m

OD= 2.78 cm

t= 0.05 cm

Fratalocchi et al., Cat. Today, submitted

0 200 400 600 800 1000 1200 1400 1600 1800 200002468

101214161820222426

packed-FOAMpacked-POCS packed-POCS (with the skin)

∆Tex

t [°C

]

Q [kW/m3]

Thermal Behaviour in FTS: Packed-POCS with skin

• POCS and POCS with the skin have similar geometrical properties: 𝜺𝜺𝑷𝑷𝑷𝑷𝑷𝑷𝑷𝑷 = 𝟎𝟎.𝟖𝟖𝟖𝟖; 𝒅𝒅𝒄𝒄𝒄𝒄𝒄𝒄𝒄𝒄 = 𝟑𝟑 𝒎𝒎𝒎𝒎; R = 1

𝑷𝑷𝒄𝒄𝑺𝑺𝑺𝑺𝒄𝒄 𝑷𝑷𝑷𝑷𝑷𝑷𝑷𝑷𝑷𝑷𝒄𝒄𝑺𝑺𝑺𝑺𝒄𝒄 𝑷𝑷𝑷𝑷𝑷𝑷𝑷𝑷 𝒘𝒘𝒘𝒘𝒘𝒘𝒘𝒘 𝒘𝒘𝒘𝒘𝒄𝒄 𝒔𝒔𝒔𝒔𝒘𝒘𝒔𝒔= 1.9

𝑷𝑷𝒄𝒄𝑺𝑺𝑺𝑺𝒄𝒄 𝑭𝑭𝑷𝑷𝑭𝑭𝑭𝑭𝑷𝑷𝒄𝒄𝑺𝑺𝑺𝑺𝒄𝒄 𝑷𝑷𝑷𝑷𝑷𝑷𝑷𝑷 𝒘𝒘𝒘𝒘𝒘𝒘𝒘𝒘 𝒘𝒘𝒘𝒘𝒄𝒄 𝒔𝒔𝒔𝒔𝒘𝒘𝒔𝒔= 2.8

∆𝑻𝑻𝒄𝒄𝒆𝒆𝒘𝒘(𝑭𝑭𝑺𝑺𝑭𝑭𝒎𝒎) > ∆𝑻𝑻𝒄𝒄𝒆𝒆𝒘𝒘(𝑷𝑷𝑷𝑷𝑷𝑷𝑷𝑷)> ∆𝑻𝑻𝒄𝒄𝒆𝒆𝒘𝒘(𝑷𝑷𝑷𝑷𝑷𝑷𝑷𝑷 𝒔𝒔𝒔𝒔𝒘𝒘𝒔𝒔 )

Fratalocchi et al., Cat. Today, submitted

New semi-pilot FTS rig with cooled reactor

Under testing, to be installed at B 18C

4. Cu-foam catalystsfor Methane Steam Reforming

Temperature profiles: comparison at dp = 600 μm

600 650 700 750

Cu10 PF10 ppi, εF=0.91, dp=0.6mm

GHSV = 10000 h-1

χ = 97.7 %Q = 56.2 W

Central T Central T (No reaction) Radial T Radial T (No reaction) Wall T Wall T (No reaction)

Cu40 PF40 ppi, εF=0.88, dp=0.6mm

GHSV = 10000 h-1

χ = 98.5 %Q = 56.0 W

Temperature (°C)

T oven = 800 °C

550 600 650 700 7500

1

2

3

4

5

6

7

8

9

10

11

12

Dist

ance

from

the

botto

m [c

m]

Temperature (°C)600 650 700 750

Packed beddp=0.6mm

GHSV = 10000 h-1

χ = 94.4 %Q = 48.9 W

Central T Central T (No reaction) Radial T Radial T (No reaction) Wall T Wall T (No reaction)

FeCr PF12 ppi, εF=0.92, dp=0.6mm

GHSV = 10000 h-1

χ = 95.9 %Q = 52.0 W

Temperature (°C)

T oven = 800 °C

550 600 650 700 7500

1

2

3

4

5

6

7

8

9

10

11

12

Dist

ance

from

the

botto

m [c

m]

Temperature (°C)

Gas

flow

= SiC filling

= Empty foam (spacing)= Catalytic bed

R. Balzarotti et al., Reaction Chemistry & Engineering, 4 (2019) 1387 – 1392

Conductive monolith, foam & POCS catalysts in tubular reactors offer great potential for the intensification of energy-related, heat transfer-limited processes:

• Fischer-Tropsch Synthesis (GtL, BtL, WtL, PtL)• COx methanation & CO2 hydrogenation (PtG)• Methanol and DME synthesis (PtC)• Selective oxidations, Hydrodeoxygenations (Biorefinery)• Methane steam & dry reforming (Blue Hydrogen)• Dehydrogenations (LOHC) …

Tronconi, Groppi, Visconti, Current Opinion in Chem. Eng.ng, 5 (2014) 55-67Kapteijn, Moulijn, Cat. Today (2020), doi: 10.1016/j.cattod.2020.09.026

Keywords for the requested new process technologies to enablemore flexible and down-scaled high-performance processing:

• Suitable for small-scale production (e.g. to exploit stranded gas)• Flexible (e.g. flow independent, RES: load changes) /modular• Enabling efficient process intensification (e.g. enhanced heat transfer) • Drop-in technology: can be inserted readily within current infrastructures

(e.g. multitubular fixed-bed vs. microchannel reactors)

Outlook

Acknowledgments

ERC AdG 2015 – Action 694910: INTENT«Structured Reactors with Intensified Energy

Transfer for Breakthrough Catalytic Technologies»