Optimization and screening of product portfolios ... - Algae · Algae Biorefineries for Europe –Towards a Sustainable Economy 17-18 October, Brussels Optimization and screening

Algae Biorefineries for Europe – Towards a Sustainable Economy 17-18 October, Brussels

Optimization and screening of product portfolios in algo-biorefinery value chains: from research through

development to scale-up

A. Kokossis(1) and D. Rooke(2)

(1) Chemical Engineering School, National Technical University of Athens, Greece

(2) Dynamic Extraction, UK


Outline

• Why screening?

• Design in the context of the biorefinery concept: challenges and limitations of the evolutionary approach

• D-Factory: a systems approach to development and scale-up

• Implementation, customization and generalization

• An open access offer to the community

• Future work & conclusions


Refineries & biorefineries

• Similarities to chemical Industries

• Holistic and parallel exploitation of supplies;

• gradual evolution, integration and innovation to exploit ‘every drop of biomass’ into a useful product

• Biorefineries: similar but more general problems

• Multiple products, feedstocks, processes

• Rich knowledge maps behind conversion paths

• regional variability and seasonality

• Drive towards local rather global solutions with additional incentives to exploit other renewables


Biorefinery challenges in a nutshell• Synthesis challenges:

• Large combinatorial problem: product against feedstocks and technologies

• Process integration challenges:

• Raw material utilization, energy recovery, environmental performance

• Centralized vs distributed production

• Modelling and flowsheeting challenges:

• Capture data from the lab and experiments

• Opportunities for novel process equipment


Process design in the context of biorefineries

• Conventional process design: start with

• start with

• Product and often a feedstock; chemistries and conversion paths

• Design, develop and integrate processing tasks

• Select and integrate economic processing paths; scale-up and cost the process to assess its economic viability

• The case of biorefineries

• How close are we set to such a description?

• Does the processing of impose algae additional constraints?


D-Factory value chain

• Which products to target? Which ones from each building block?

• Complementary integration schemes?


Challenges• Holistic use implies multi-product biorefineries

• Integration is possible within a process, across different processes also considering the full plant

• Largest promise from non-energy products: short life cycles, volatile prices

• Process equipment could/should be reconfigured to process other algal strains, not only one particular case

• The future plant has to be flexible as specialties could gain additional value in the future (e.g. formulation into useful end-user products) or have their prices drop (e.g. expiration of licenses, competition etc)


Selection of product portfolios: how about a straightforward evolutionary approach?

… Start with a product (one of your choice)

… Evolve the design to incorporate additional products

… continue this way, step-by-step, towards a multiproduct biorefinery


Let’s start where the history started from…

Cultivation

Harvesting Oil extraction

Product recovery


Introduce new product: b-carotene

▪ Conditions in osmotic tanks do not favor co-production.

▪ Settling tanks are redundant.

▪ Scope to replace spray dryers and belt press

▪ Provided that protein meal is used as food supplement (e.g. fishmeal), solvents have to be replaced


New result: excellent but process engineering changes are too many…

• Venture is profitable but integration scheme is very different • Retrofitting the first scheme to the second is not economical


Next: introduce xanthophylls and galactolipids…

1 2

3

1 Glycerol, carotenes mixture

2 Glycerol, pure carotenes, pure xanthophylls

3 Glycerol, pure carotenes, pure xanthophylls, galactolipids


New result: similar, simply more pronounced..

• Profitability improves as you add products BUT• Integration and processing paths differ dramatically so that

retrofitting the plant is essentially impossible• Selection of new products to produce never straightforward

1

2

3


The evolutionary approach to process development could turn into

a free fall to the Death Valley


The D-Factory systems approach

… Combine state-of-the-art of systems engineering (synthesis, process integration, advanced flowsheeting..)

… Capitalizes on advanced modelling and optimization

… Possible to generalize and scale-up into very large problems


Flexible, sustainable plants

sStrains

Screening and process

development

Select product portfolios

Stage I: Synthesis

Select technologies,target efficiencies , Stage II: Process

integration

Process flowsheeting, process development

Stage III: Costing & analysis

Steps of the systems methodology

• High-throughput screening• Could address uncertainty analysis• User interaction with decision-support process


Stage I – Screening: methodological approach

• Model based approach where optimization technology is used to select the appropriate options

• Basic idea: combine all possible options into one model (superstructure)

• Possible does not mean exhaustive; combines knowledge from different domains

• Combinations may be encouraged or prohibited according to practical constraints

• Optimize model against selected objectives to screen and prioritize options


So, what we screen for?

• Quantities and qualities of algal paste

• Separation technologies

• Membranes

• Supercritical CO2 extraction

• Solvent extraction

• Chromatography

• Sequencing of separation (processing stages)

• Products and product portfolios


Some of the D-Factory options…

Feedstock Processes Products

Ultrafiltration membrane (solid-liquid, liquid-liquid)

Nanofiltration membrane

Ethanol extraction (solid-liquid, liquid-liquid)

Heptane extraction (solid-liquid, liquid-liquid)

ScCO2 extraction (solid-liquid, liquid-liquid)

H2O extraction

HPCCC

Dunaliella paste

GlycerolCarotenoids▪ cis β-carotene▪ trans β-carotene▪ other carotenes▪ zeaxanthin▪ lutein▪ violaxanthin▪ phytoene

Lipids▪ pufas▪ chlorophyll a▪ chlorophyll b▪ EDK vitamins

Proteins▪ glycerol enzymes▪ carbonic anhydrase

.

.


Building the screening model…


… and optimizing value chain and technology selection

25-27/11/2015 XXIV Month Meeting, Monzón - Spain

Paste

1_hep_extr_SL

2_solv(a)_extr_SL scCO2_extr_LL

sep_1 HPCCC_1

algae_4 car_lip

proteins residue

H2O_extr

glyc_enzymes

carb_anhydrase

lip car

pufas

EDK

chlor_a

chlor_b caroteneszeaxanthin

violaxanthin

cis_b_car

lutein phytoene

trans_b_car

Best solution

o 6 processes

o 13 products

o Equipment cost = 11000 M$/yr

o Profit = 87300 M$/yr


… pointing to backup optionsPaste

1_solv(a)_extr_SL

2_eth_extr_SL

sep_1 HPCCC_1

proteins algae_1

residue

H2O_extr

glyc_enzymes carb_anhydrasegl_car_lip

pufas

EDKchlor_a

chlor_bcarotenes

zeaxanthin

violaxanthin

cis_b_carlutein phytoene

trans_b_car

hep_extr_LL

car_lip

scCO2_extr_LL

lip car

glycerol

Best solution including glycerol

o 7 processes

o 14 products




Paste

1_solv(a)_extr_SL

2_eth_extr_SL

sep_1 HPCCC_1

proteins algae_1

residue

H2O_extr

glyc_enzymes carb_anhydrasegl_car_lip

pufas

EDKchlor_a

chlor_bcarotenes

zeaxanthin

violaxanthin

cis_b_carlutein phytoene

trans_b_car

hep_extr_LL

car_lip

scCO2_extr_LL

lip car

glycerol

Best solution including glycerol

o 7 processes

o 14 products



… or customized around preferences for specific products or technologies


Multiple solutions

Study the impact of process/product selection on the profit

Plotting the ‘big picture’


‘Popular technologies’


CarotenoidsLipidsProteins

Popular products and product portfolios


Stage II – Process and energy integration

• Energy integration

• Set targets ahead of design

• Process integration as well as process to process integration (across different paths)

• Water integration

• Set targets ahead of design

• Propose re-use, regeneration, recycle strategies


Energy integration

Cold streams Need heating

Hot streams Need cooling

Solution 1

Solution 2

Solution 3

Energy analysis per solution


Energy use

Energy intensive processes:

→ centrifugation

→ distillation

Why:

✓ large quantities of water

✓ high purity separation

Energy sensitivity0112233

Ener

gy (

MW

) Solution 2

012345678

Ener

gy (

MW

)

Solution 3

Energy integration

0

1

2

3

4

5

6

Ener

gy (

MW

)

Base case


Base case

StreamFlow

[kg/hr]

Recycle

ratio

Feed from

pond131.626

99.9%Recycle 131.544

To process 82

StreamFlow

[kg/hr]

Recycle

ratio

ETHANOL 25077.2%

RECYCLE 193

StreamFlow

[kg/hr]

Recycle

ratio

Fresh

Water3000

99.9%

Recycle 2997

Water cycle Ethanol cycle Hexane cycle

Water and solvent re-use and regeneration


Stage III – Costing and economic analysis

• Flowsheeting using commercial packages

• Aspen Plus, Hysis, SuperPro, UniSim

• Emphasis on simulation: at this stage most decisions are made

• Costing and profit analysis

• Combination of empirical and commercial models

• Large uncertainty in market sizes and prices due to the novelty of the products

• Screening platform could be of critical importance to assess market volatility and uncertainty


Flowsheeting from commercial packages…Algae-biorefinery yields

(1100 tn/yr algae paste)

Product tn/yr

glycerol 300

α-carotene 9

β-carotene 70

xanthophylls 8.8

galactolipids 90

Solution 1

Solution 2

Solution 3


…down to process layout


Scenario 1

Equipment cost (M$)

13

Total operating cost (M$/yr)

13.2

Total capital cost (M$)

65.8

Revenue (M$/yr) 57.4

Scenario 2

Equipment cost (M$)

16.9


24.1


82.8


Scenario 3

Equipment cost (M$)

17.2


19.3


88.8


Product portfolio:

o Glycerol

o Carotene mixture

Product portfolio:

o Glycerolo Β-caroteneo A-caroteneo Luteino Zeaxanthino Violaxanthino Phytoene

Product portfolio:

o Glycerolo Β-caroteneo A-caroteneo Luteino Zeaxanthino Violaxanthino Phytoeneo MGDG

Cost summaries


Scenario 1

Equipment cost (M$)

13


13.2


65.8

Raceway ponds

CentrifugeSolvent

extraction S-L

Solvent extraction

L-L

0

1

2

3

4

5

6

7

8

0

1

2

3

4

5

cultivation pond centrifuge solvent extractionL-L

solvent extractionS-L

Op

era

tin

g co

st (

$/y

r)

Equ

ipm

en

t co

st (

M$

)

Process

Equipment Operating

Breakdown of equipment cost


Raceway ponds

CentrifugeScCO2

extraction S-L

HPCCC

Solvent extraction

S-L

Nanofiltration

Ultrafiltration

Scenario 2

Equipment cost (M$)

16.9


24.1


82.8

0

2

4

6

8

10

12

0

1

2

3

4

5

Op

era

tin

g co

st (

$/y

r)

Equ

ipm

en

t co

st (

M$

)

Process

Equipment Operating

Breakdown of equipment cost (2)


Scenario 3

Equipment cost (M$)

17.2


19.3


88.8

012345678

0

1

2

3

4

5

Op

era

tin

g co

st (

$/y

r)

Equ

ipm

en

t co

st (

M$

)

Process

Equipment Operating

Raceway ponds

CentrifugeSolvent

extraction S-L

HPCCCScCO2

extraction L-L

Nanofiltration

UltrafiltrationSolvent

extraction S-L

Breakdown of equipment cost (3)


A typical breakdown?

Investment policies could make a difference!


Short payback times possibly hide…

… optimistic selling price of products


Systems platform for screening

• What is made up from?

• Data (properties: thermodynamic, transport, economic, environmental)

• Models (Stage I: synthesis models and optimization; Stage II: process integration; Stage III: process flowsheets)

• Knowledge and workflows (value chain; also to include product reports, images etc.)

• The integration constitutes knowledge asset to share (or sell) to third parties

• Empowered by ontology engineering


User access: looks-and-feel

• New technologies and products can be included• Preferences to select/deselect technologies or products


Optimization and screening

• Further access: technological/economic data• Analytics: compares solutions, breakdown cfc costs etc


Generalization


Generalization

A

A1 A2

A3 A4 A5

B

1. Formulate value chains

2. Identify common fractions

3. Customize product portfolios

Product selection:

• Market needs• Price• Amount• Non competitive

4. Integrated value chain

B1 B2 B3

B4 B5 B6 B7

Algae characteristics:

• Common properties• High value chemicals as products

A1 B3

A4

Β1

A5 B5 B6

A1/B3

A/B

A2 B3B1

A4 A5 B5 B6

P1P2 P3

P4

P5 P6 P7 P8


Biorefineries made up by different strains

Microalgae feedstock

▪ Dunaliella▪ Haematococcus▪ Nannochloropsis

Target products

▪ B-carotene▪ Astaxanthin▪ Lipids


Biorefinery I: Dunaliella

Resistant to potential pollutants

Growth in medium with high NaCl conc.


Biorefinery I: Dunaliella

Capital cost (M$) 89

Operating cost (M$/yr) 31.2


B-carotene = 94% of revenue

4


Biorefinery II: Haematococcus

Resistant species with thin cell wall

Cells adaptable to external conditions by morphological adjustments


Biorefinery II: Haematococcus

Capital cost (M$) 80


Revenue (M$/yr) 108

Astaxanthin = 80% of revenue

4


Biorefinery III: Nannochloropsis

Can store large amount of lipids

Great candidate for outdoor mass cultivation


Biorefinery III: Nannochloropsis

Capital cost (M$) 96.7



Proteins = 50% of revenueViolaxanthin = 37% of revenue

3


A flexible biorefinery of the future

Potential for min. 10 products

83.3% process overlap

Cultivation ponds

Water Nutrients

Centrifugation DryingCell

extractionLiquid

extraction

Remainingcell

extraction

HPCCC

Membrane

Glycerol Lipids

CarotenoidsLipids

Proteins


Conclusions

• Biorefinery design and optimization brings forward new and important challenges

• Screening and scoping is important to preview opportunities ahead of detailed developments

• One could use the technology to build significant flexibility and robustness that would prevent unsuccessful investment

• The D-Factory remains a particularly promising platform to invest also possible to incorporate other strains and culture

Documents

Optimization and screening of product portfolios ... - Algae · Algae Biorefineries for Europe –Towards a Sustainable Economy 17-18 October, Brussels Optimization and screening