Integration of Biorefinery concepts in Process Industries

Thore Berntsson, Professor Department of Energy and Environment Division of Heat and Power Technology

CHALMERS UNIVERSITY OF TECHNOLOGY

What is a Biorefinery?

Two examples of definition: • “Biorefining is the sustainable processing of biomass into a

spectrum of marketable products and energy.” From IEA • “A biorefinery is a facility that integrates biomass

conversion processes and equipment to produce fuels, power, and chemicals from biomass.” From NREL

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Research Theme: Biorefineries - Process Integration Issues

Biorefinery Plant Industrial Process Plant

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Cellulose & Lignin wood, black liquor,

grass

Starch wheat, corn, potatoes

Sugar

Oil rapeseed, palmoil, soy

Rest flows from agriculture, forstry,

industries, societal waste etc, e.g. straw, sawdust,

manure, sludge, food waste.

Fermentation of sugar

Ethanol

BIOMASS CONVERSION PROCESS ENERGY CARRIER

Electricity Combustion

Methane

Hydrogen

Fischer-Tropsch Diesel

DME (Dimehtyleter)

Methanol

Gasification to syngas

(CO and H2)

Cracking Bio-oils treated with

hydrogen HVO

Pressing and esterification

FAME

Anearobic digestion

Biogas

Example of biofuels and conversion processes

Acid or enzymatic hydrolysis

Gasification Pyrolysis

Fermentation Catalytic conversion Upgrading

Liquid fuels Hydrocarbons, methanol, hydrogen,

SNG chemicals, materials etc.

Bio-oils Syngas

(H2, CO, CO2, H2O) Heat

Electricity Sugars

Ethanol, butanol

Woody biomass

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Woody biomass

Gasification of biomass

6 (Milne et al 1998)

H2, CO, CO2, H20, CH4, (N2), tars

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Example of a Fermentation Route

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Degrees of Freedom

The biomass feedstock • Forest biomass • Agricultural biomass • Organic waste • Algae • Etc

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Degrees of Freedom

The conversion processes • Gasification • Fermentation • Pyrolysis • Torrefaction • Drying • Hydrolysis • Separation technologies • Gas cleaning • Etc

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Degrees of Freedom The end products • Bulk Products, high value materials, specialty chemicals • Examples of bulk products: • Fischer-Tropsch diesel • SNG • DME • Methanol • Ethanol • Hydrogen • Furfural • Carbon fibres • Polyethylene • Green electricity • Heat

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Several New Approaches for Strategic Decision-Making for Biorefineries

Some Examples: • Systematic screening of biorefinery concepts • Value and supply chain management and evaluation • Optimal synthesis of biorefinery concepts • LCA-based evaluation of biorefinery concepts • Future scenarios for evaluation of biorefinery concepts • Decision-making under uncertainty regarding future prices

and policy instruments

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The Advanced Composite Curves below the pinch are: • Cold Utility curve, representing the composite of the

cooling media • Actual Cooling Load Curve, representing the highest

possible temperatures of the excess heat without additional internal heat exchanging

• Theoretical Cooling Load Curve, representing the highest temperature levels at the actual level of hot utility (not equal to the GCC below the pinch)

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Advanced Composite Curves

Pinch divides process into heat source and heat sink

QHmin

QHmin

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Advanced Composite Curves

With heat exchanger additions, the temperature levels of the excess heat can be increased compared to existing levels. The advanced composite curves identify the theoretically highest possible level at given levels of hot and cold utility. In the same way, the advanced composite curves identify the lowest possible temperature levels for heat transfer to the system above the pinch. Both aspects are crucial for identifying true process integration opportunities in biorefineries.

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Advanced pinch curves for the background process

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Optimization

Complicated, many optimization parameters • Technical parameters, e g feedstock, upgrading processes,

type of products • Economic parameters, e g energy prices, investment costs

for new technologies, feedstock and product prices • Policy instruments, e g CO2 charge, green certificates,

energy taxes • Build margin technology for e g power production, use of

biomass

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Optimization

All optimization parameters will change considerably during the service life of a biorefinery. With the ENPAC tool, the economy and environmental performance for a biorefinery can be evaluated at different scenarios for future changes and “robust” options can be identified.

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Research Theme: Scenarios for assessing profitability and carbon balances of energy

investments in industry

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Results for year ~2030 (with CCS)

BLGMF:CCS RB:ElectricityBLGCC:CCS RB:CCSLignin:Wood fuel Lignin:Oil

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Some Process Integration Principles

Two large process parts shall be integrated. This can be done at several levels: • Process integration within the biorefinery separately • Process integration of the host process separately • A total site or foreground/background analysis of the two parts • A process integration analysis treating all streams as

parts of one large process Do always the fourth level first to establish the theoretical potential. Then include practical and economic constraints.

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Examples of Industrial Biorefinery Process Integration Studies

Pulp and Paper Industry • Biomass gasification and production of electricity, methanol or Fischer-Tropsch

diesel • Black liquor gasification with production of DME or green electricity • Ethanol production using partly existing pulping equipment or docked to a pulp mill • Lignin precipitation and upgrading • Precipitation and upgrading of hemicellulose with water extraction

Oil Refineries • Biomass gasification and production of hydrogen or Fischer-Tropsch diesel

Petrochemical industry • Biomass gasification and production of methanol or SNG (which can be further

converted to e g polyethylene)

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Energy efficiency measures in a pulp mill converted to an ethanol production plant

Rickard Fornell

• Co-op with Innventia (process development).

• Process integration studies by Chalmers. Aims • Study energy efficiency measures in the conceptual process.

• Apply results in various ways (other raw-materials and different new concepts).

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Method:

Evaporation

Distillation

Background process

~

Alkalinepretreatment

Evaporation

Lignin fuel

Recoveryboiler

HPSteam

SteamTurbine

Electricity

Hydrolysis+Fermentation Fuel grade Ethanol

Condensates

Raw material

Enzymes

Distillation

Causticizing

MP/LPSteam

Acid

Yeast

Spentliquor

Molecularsieves

pH adj.

Lime kiln

CO2

Cooking liquor

dewatering

Washliquor

Distillationresidue

Step 1: Divide the process in 3 parts. Evaporation – studied in detail Distillation – studied in detail Background process – HX network Step 2: Combine different parts in energy efficient ways (Heat integration)

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Methods used Process integration studies:

- Pinch analysis (heat integration) - Targeting - Bg/Fg curves - Advanced composites - Tank curves

- Process simulations

- Evaporation (OptiVap) - Distillation (Aspen Plus) - DME (Aspen Plus)

- Economic analysis

- Previous cost information - Aspen PEE (simulations) - Scenario tool (ENPAC)

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Background process

Background process

Evap Dist

Heating demand

Cooling demand

Tem

pera

ture

[C]

Energy [MW]

1. Improve internal heat recovery in BG process:

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Background process

Background process

Evap Dist

Heating demand

Cooling demand

Tem

pera

ture

[C]

Energy [MW]

1. Improve internal heat recovery in BG process:

Improve HX network

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Background process

Background process

Evap Dist

Heating demand

Cooling demand

Tem

pera

ture

[C]

Energy [MW]

2. Improve heat integration externally:

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Background process

Evap Dist

Heating demand

Cooling demand

Tem

pera

ture

[C]

Energy [MW]

2. Improve heat integration externally:

Distillation and/or evaporation integrated with BG process

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Some General Findings

• Through Process Integration between a biorefinery concept and a process industry, energy efficiency measures can in practically all cases be found

• Energy saving opportunities for the total system are normally high, up to 25%

• The reduction of CO2 emissions through integration of biorefineries with process industries depend to a high extent on the marginal production technology of energy, especially power, in society.

• The economic benefits of integrating biorefineries are in most studied cases reasonable or high, but depend totally on future conditions regarding policy instruments, i e on future CO2 charge levels

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