Pilot-scale CFP Commissioning: Creative Problem Solving and Lessons Learned

Katherine Gaston

tcbiomassplus2019

October 8, 2019

NREL | 2

Staged Multi-Scale Evaluation Improves Research Efficiency

Catalyst: 1g

Biomass: 25 mg/run

Microscale Reactor

Uses/Purpose:• Rapid catalyst screening• Preliminary product analysis

(no condensed oil)• Batch experiments• Mechanistic insight

• Catalyst evaluation with continuous biomass feed

• Assess operating conditions• Full product/yield analysis• Extended time on stream• Fixed/Fluidized bed (not

representative of riser)

• Process evaluation / integration with industrially-relevant riser

• Assess operating conditions compared to lab-scale

• Co-processing of biomass and petroleum feeds (liq. and gas)

• Evaluation of process operability / uptime

• Identification & assessment of scale-up challenges & impacts

• Generate significant product quantities

R-Cubed (Pilot Scale)DCR (Small Pilot Scale)Laboratory Scale Fluid/

Fixed Bed Reactor

Process and catalyst evaluation at multiple scales:• Improves research efficiency, thus reducing cost• Provides data that is directly transferrable to industry partners• Allows for a tiered catalyst and process development approach

500g

0.5 kg/h

2kg

3 kg/h

100kg

20 kg/h

NREL | 3

TCPDU Process Flow Diagram

NREL | 4NREL | 4

Challenges / Creative Problem Solving

• Design Constraints

• Measuring & controlling catalyst flow rate

• Pressure & level control

• Plugging in exit lines

• Air regeneration – complete coke combustion for catalyst efficiency

NREL | 5

Design Constraints

• Must have built-in flexibility• Ceiling height limit

– Must account for thermal expansion

• Floor loading limit (Techlok flanges)

• BPVC: limited to 6-in. diameter pipe

• Highly fluidizable catalyst (Zeolite)

NREL | 6

R3 Process Flow Diagram

4-inRiser

AirRegen. (FBR)

SteamStripper

3-inTransferRiser

Gas Exits

NREL | 7

R3 Process Flow Diagram

Catalyst Level measured by DP

Regen. DP

Stripper DP

Riser DP

NREL | 8

How to Measure Catalyst Mass Flow

0

5

10

15

20

25

30

35

12:30 13:00 13:30 14:00

Cat

alys

t Le

vel,

kPa

Time

• Loaded 5 kg shots of catalyst

• 1 kg = 0.64 kPa at 60 kPa

NREL | 9

How to Measure Catalyst Mass Flow

0

5

10

15

20

25

30

35

12:30 13:00 13:30 14:00

Cat

alys

t Le

vel,

kPa

Time

• Loaded 5 kg shots of catalyst

• 1 kg = 0.64 kPa at 60 kPa

y = 0.64x + 13.42R² = 1.00

0

5

10

15

20

25

30

35

0 5 10 15 20 25 30

Cat

alys

t Le

vel,

kPa

Weight catalyst loaded, kg

NREL | 10

R² = 0.994

R² = 0.998

R² = 0.999

0

50

100

150

200

250

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7C

alcu

late

d C

atal

yst

Flo

wra

te, k

g/h

Riser DP, kPa

HIGH MID LOW

Catalyst mass flow required for kinetics

• Timed the transfer of catalyst from one FBR to other

• Simulated high/mid/low process gas flows with N2

ሶ𝑀 = ∆𝑃𝑠𝑡𝑎𝑟𝑡 − ∆𝑃𝑒𝑛𝑑 ×1 𝑘𝑔

0.64 𝑘𝑃𝑎×

1

∆𝑡

NREL | 11

Controlling catalyst flow via slide valves

• First generation: temperature at Riser exit (TE709B) controlled catalyst flow

– Difficult due to thermal mass of riser & external heaters (thermocouple not sensitive to catalyst flow)

• Next generation: keeps catalyst flowrate constant, as measured by DP across riser (PDIT700)

NREL | 12

Pressure Control in Fluidized Beds (Regen/Stripper)

DP across slide valve must be positive

y = 0.97x - 3.81R² = 0.99

0

1

2

3

4

5

6

7

8

0 5 10 15

CYC

LON

E D

P, k

Pa

LEVEL, kPa

3.3 kPa

7.2 kPa

MUST BE GREATER THAN

NREL | 13

Level Control & Maximum Level in FBRs

0

5

10

15

10:50 11:00 11:10 11:20

Flu

idiz

ed B

ed

Leve

l, kP

a

Regen. St. Stripper

25

50

75

Pre

ssu

re, k

Pa

Regen. Cyclone Outlet

Regen. Headspace

Regen. Level increases as Stripper Level decreases

DP across cyclone inverts

~13 kg of catalyst out cyclone gas exit

Max level in Regenerator plugs

Sidearm

NREL | 14

Hot Gas Filtration

• Catalyst + water = Mud = Plugged Sidearms = Catalyst out

• Hot Catalyst + water vapor = ok

• Required on ALL exit streams

CRITICAL TO SUCCESS OF OPERATION

NREL | 15Upsized diameter of entire line

Upgraded exit lines to remove catalyst particles while hot

Added heat exchangers in parallel

Added filtersAddedblowdown

Cyclone moved upstream

NREL | 16

Insufficient Regen Air

• Initial Design: Coke loading estimated from preliminary results on Bench-scale FBR

• No O2 measured on regen exit

• Limited by reactor geometry:

– Exit line too small diameter

– Too much carryover (elutriation) at higher air flow

0

2

4

6

8

10

12

vol%

CO CO2 O2

0

10

20

30

40

50

60

0 50 100 150

slm

Time (min)

Air flow into reactor

Early experiments, max air 50 slm

NREL | 17

120, 43

1

10

100

1000

75 100 125 150 175 200 225 250 275

Elu

tria

tio

n R

ate,

kg

/hr

Total Gas Flow, SLPM

Elutriation of Catalyst at Increased Air Flow

Credit: Bruce Adkins (ORNL) (using PSRI models)

NREL | 18

Add Cyclone Return into Regenerator

• Increased air flow carries over MUCH more catalyst

• Effectively increased Regen. diameter

• Installed cyclone to return catalyst into reactor

• Tricky design: must keep horizontal section of return pipe fluidized

NREL | 19

Air Regeneration Results

Coke on Catalyst (%C by wt) Insufficient

Regen

Post-stripper, after ~2 hours 0.94%

Post-regen, after ~2 hours 0.66%

Insufficient Regen

Complete Regen

Post-Stripper Post-Regen

Post-Stripper Post-Regen

0

5

10

15

20

20:00 21:00 22:00 23:00 00:00

vol %

CO CO2 O2

Coke on Catalyst (%C by wt) Insufficient

RegenComplete

Regen

Post-stripper, after ~2 hours 0.94% 0.58%

Post-regen, after ~2 hours 0.66% 0.01%

NREL | 20

Catalyst mass flow rate, which is critical for VPU kinetics,

– can be empirically determined by change in level in fluidized bed reactors,

– then correlated to differential pressure across Riser,

– as long as gas flow rate stays constant

Lessons Learned

NREL | 21

• Pressure in top of fluidized beds varies linearly with level of catalyst in bed

• D Pressure across Regen. cyclone must be positive

- Flowrate out sidearm must be greater than flow in, or pressure flips and catalyst empties

Lessons Learned

NREL | 22

DON’T PLUG SIDEARMS

- Don’t overflow fluidized beds

- Filter catalyst particles out while hot (mud plugs lines & is difficult to clean out)

Lessons Learned

NREL | 23

NEED PLENTY OF O2 FOR REGENERATION

- High-risk to scale up using bench-scale data from dissimilar reactor system

- We mitigated catalyst elutriation out of Regen. by adding a cyclone

- Ideally, disengagement zone (freeboard) keeps catalyst in reactor

- Pure oxygen is dangerous & expensive, but plausible

Lessons Learned

NREL | 24

Acknowledgements

NREL: Danny Carpenter, Tim Dunning, Chris Golubieski, Rebecca Jackson, Ray Hansen, Matt Oliver, Jessica Olstad, Marc Pomeroy, David Robichaud, Kristin Smith

CCPC: Bruce Adkins, Jim Parks (ORNL)Xi Gao, Bill Rogers (NETL)

DOE Advanced Development & Optimization program (ADO)

10/9 @ 4pm Jessica Olstad (NREL)Co-Processing Catalytic Fast Pyrolysis Oils with Vacuum Gas Oil in a Davison Circulating Riser – Upgrading Track

www.nrel.gov

Questions?

This work was authored by the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. Funding provided by U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Bioenergy Technologies Office. Theviews expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes.