Bridgwater

7/25/2019 Bridgwater

1/19

Biomass and Biofuels

.

BioEnergy Research Group

Aston Universit Birmin ham B4 7ET

AV Bridgwater 2008

Biomass Energy crops

Agricultural and

Industrial &consumer wastes

2


2/19

Why convert biomass?

Biomass is a low energy density material with a low bulkdensity

It is a widely dispersed resource

It is difficult and costly to transport and store

In N Europe, yields are limited by sunlight, rather thanwater as in S Europe, and land quality

produce more than about 100,000 dry t/y (~ 25MWe)

Biomass is being increasingly traded internationally withone proposal for a 3 Gwe power plant in Rotterdam

based entirely on imported biomass.

Renewable transport fuelsOxygenates

Methanol Ethanol Butanol Mixed alcohols Dimethyl etherHydrocarbons

Synthetic diesel Synthetic gasoline Methane (SNG)Other

H dro en


3/19

1st and 2nd generation biofuels

First generation biofuels are from foodstuffs such as: Ethanol from sugar or corn about 2 t/ha/y in Europe and North

mer ca, up to -7 t a y rom sugar cane n raz

Biodiesel from vegetable oils about 1-1.2 t/ha/yThese are, and will continue to be, important in introducingbiofuels although the productivity is low.

Second generation biofuels are from whole crops such aswood, energy crops, residues, wastes. These are known asligno-cellulosic feedstocks, Products include:

Synthetic diesel about 4 t/ha/y Methanol about 8 t/ha/y Ethanol about 5 t/ha/y

Feeds, processes, products

Oil plantsStarch & sugarsResiduesResidues

1G 2G

Biologicalconversion

Thermalconversion

Esterification

Ethanol;Butanol;

Biodiesel(FAME,RME);

Synthetic h/c;Ethanol; Butanol;

Chemicals;Power; Heat


4/19

Thermal vs biological

Thermal conversion Dr feed needed Fast processes

Less selective - Mixed products

Biological conversion

Wet feed acceptable Slow processes More selective - Single product generally (e.g. ethanol)


MethanolGeneration

2Process

Thermal Ethanol Butanol Mixed alcohols

1 & 21 & 2

2

Biological or ThermalBiological or ThermalThermal

Dimethyl etherHydrocarbons

2

Thermal

Synthetic diesel Synthetic gasoline

22

ThermalThermal

Methane (SNG)Other

H dro en

1 & 2

1 & 2

Thermal

Thermal or Biolo ical


5/19

Bioethanol Limited to 5% in gasoline in Europe (E5). Newer vehicles

may tolerate 10% (E10)

E85 (85% ethanol) is used in USA and E100 in Brazil

Some problems remain

compatibility

Engine warrantiesapour pressure

Materials Fuel compatibility

Flexible fuel cars available

that can operate on any

Bioethanol in Brazil


6/19

Bioethanol technology Mature technology for 1st generation from sugar and corn.

Developing technology for 2nd generation fromgnoce u os cs. ea ures nc u e:

Acid/enzyme hydrolysis is needed to release the C6 and C5sugars and separate lignin. This needs to be optimised. C6 sugar fermentation is commercial. C5 sugars fermentation needs to be demonstrated.

Lignin needs to be utilised for energy efficiency

Separation by distillation is preferred, but other separationmethods are being developed such as membranes.

ethanol, and significant efficiency improvements are

needed.

2 Generation bio-ethanol

Biomass

HydrolysisGasification

Ethanol synthesis Fermentation

Byproducts

ResiduesDistillationWastes

Bioethanol


7/19

Biodiesel

Methyl (or ethyl) esters of vegetable oile.g. rape, soy, sunflower etc to reduceviscosity of raw oil and improve other

properties.RME = Ra e Meth l Ester

FAME = Fatty Acid Methyl Ester

Applications

Limited to 5% in diesel in Europe dueo eng ne warran y, ma er a s ancompatibility concerns


MethanolGeneration

2Process

Thermal Ethanol Butanol Mixed alcohols

1 & 21 & 2

2

Biological or ThermalBiological or ThermalThermal

Dimethyl etherHydrocarbons

2

Thermal

Synthetic diesel Synthetic gasoline

22

ThermalThermal

Methane (CSNG)Other

H dro en

1 & 2

1 & 2

Thermal

Thermal or Biolo ical


8/19


9/19

1: Biofuels via gasification

Biomass

Syngas

Methanol Fischer Tropsch

MOGDMTG

Refining

Gasification + Fischer-TropschThe minimum economic size of Fischer Tropsch is widelyconsidered to be 20,000 bbl/day or 1 million t/y biofuels.

This requires about 5 million t/y biomass.

Biomass is a widely dispersed resource that is collected and.

This leaves 2 options:

arge gas ca on p an s n egra e w syn es s aup to 5 million t/y biomass input.

downscaled Fischer-Tropsch (FT) hydrocarbonsynthesis. Maybe 100,000 to 500,000 t/y biomass


10/19

Gasification + Fischer-Tropsch

OrEither

Fischer

Biomass

ropsc

Gasification

Challenges of gasification The necessary scale of solid biomass gasification has

not been demonstrated for either option

Gas cleaning and conditioning is a major technical andeconomic challenge. This increases as the extent and

.consistent woody or annual energy crops are currently

favoured, but these will face increasing competition. In all cases, economies of scale and feed costs

dominate biofuel product costs

o-process ng w coa s an n eres ng poss y


11/19

Alternative biomass transport

Conversion of biomass to a liquid at source will reducetransport costs, reduce environmental concerns andreduce gasification costs.

Pressurised oxygen gasification of liquids is easier and

Fast pyrolysis is an available technology that canroduce hi h ields of mobile li uid with u to 10 times

the energy density of biomass and in a form that iseasier to store and to transport and to process.

Pyrolysis for pretreatmentBiomass

as pyro ys s

75% wt. liquid

Syngas

Methanol Fischer Tropsch

MOGDMTG

Refining


12/19

Pyrolysis + Fischer Tropsch

Biomass

F-T

Biomass

Gasn.Biomass

Capital costs16000

Capital cost, million

12000

14000 small FT

unproven

6000

8000

+Small pyrolysis

2000

4000

Lar e asification + FTLarge

proven

0

0 2 4 6 8 10 12

Biomass input million dry t/y

unproven


13/19


14/19

Methanol based processes The same gasification considerations apply as with FT

Methanol well established technology from natural gas.

MTG Methanol To Gasoline commercial technology

MOGD Methanol to Olefins, Gasoline and Diesel well.

BUT

MeOH, MTG, MOGD are more selective

FT diesel is about 50% efficient on anenergy basis,

+on an energy basis BUT requires an

additional processing step.

Routes to bio-hydrocarbon fuels1. Thermal gasification to synthetic hydrocarbons

a + Fischer Tro sch

b) + Methanol synthesis + upgrading by MTG or MOGD

2. Pyrolysis + upgrading

3. Hydro-processing vegetable oil


15/19

2: Upgrading bio-oil directlyDirect production of liquids is attractive. Production ofhydrocarbons requires rejection of the oxygen in bio-oil:

Hydro-processing rejects oxygen as H2O

Requires hydrogen, high pressure -

refining, without considering the hydrogen requirement

Zeolite cracking rejects oxygen as CO2 Close coupled process requiring constant catalyst regeneration as

in a FCC unit.

No hydrogen requirement, no pressure Gives projected yield of around 20% aromatics for refining This has only been researched.

Costs of upgraded bio-oilYield,wt%

/tproduct

HHV,GJ/t

/GJproduct

/toe

Wood eed da 7 45

Pyrolysis oil output 70 147 19 8 331

H drotreated oil 26 516 42 12 529

Diesel output 23 592 44 13 578

Aromatics output 21 471 44 11 460

Gasoline output 22 453 44 10 443

FT diesel 20 42

MTG asoline 26 43

Crude oil at $100/bbl - 560 43 15 560

,


16/19

Routes to bio-hydrocarbon fuels

1. Thermal gasification to synthetic hydrocarbons

a + Fischer Tro sch

b) + Methanol synthesis + upgrading by MTG or MOGD

2. Pyrolysis + upgrading

3. Hydro-processing vegetable oil

3: Hydro-processing vegetable oil Bio-diesel (by esterification of crude vegetable oil) is

currently limited to 5% of conventional diesel.

Vegetable oil can be hydroprocessed to synthetic dieseland Neste have built a 100,000 t/y plant in Finland and

,oil and other vegetable oils.

Generation 1 as feed is a foodstuff and roduct is 2ndgeneration equivalent

The hydrogen requirement is much less than fastpyro ys s qu , u e vege a e o pro uc v y,sustainability and food competition issues remain.


17/19

Biorefinery concepts Integrated production of higher value chemicals and

commodities, as well as fuels and energy,

, ,

benefits, minimise wastes

Secondary

processing

Tertiary

processingBiomass Primary

emcas

Commodities

Fuelsprocess ng Electricity

Heat

Byproducts and wastes

Biorefinery optionsWaste waterGasification

Distillation

H dro-

EthanolFermentation

Lignin

processing

Biomass

ChemicalsH2

Fuels

ChemicalsPyrolysis

Gasification Synthesis

Off-peak

electricit

Chemicals

Electrolysis


18/19

Scenarios

Euro eFeed

MarketsFuels and

ProcessingFeed

production EU

BiorefineryFeedproduction

Preparation,processing

Fuels andchemicals

OverseasLocal

markets

Challenges Improve 1st and 2nd generation bioethanol technology Improve lignocellulosics pretreatment for 2nd generation Demonstrate large scale thermal gasification and gas

cleaning & conditioningeve op sma sca e y rocar on syn es s

Develop and demonstrate fast pyrolysis liquids upgrading

Develop integrated biorefineries Improve catalysts Robustly compare alternative systems Consider CCS with bioenergy Ensure there is a significant environmental contribution

ons er omass an o ue ra ng


19/19

Key issues

Apart from technology improvement and demonstration,

Competition for land in producing food or fuel. This ismore important in land scarce countries such as the UK.

Competition between use of crops for food or fuel

omass mprovemen y e an qua y

Sustainability of biofuels

Thank you

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