Gasification · A. Nordin, et al. (2005). Initial Review and Evaluation of Process Technologies and Systems Suitable for Cost-Efficient Medium-Scale Gasification for Biomass to Liquid

Gasification

Prof.dr.ir. Wiebren de Jong (TU Delft, NL; RUG, NL)

Biofuels Summer School

2018

Thursday 21 June 2018

My background

Faculty 3mE, Department of Process & Energy

6 sections:

Energy Technology (prof. Boersma, chair)

Large-Scale Energy storage

Engineering Thermodynamics (prof. Vlugt)

Intensified Reaction and Separation Technology (prof. Stankiewicz)

Aero- and hydrodynamics (prof. Westerweel)

Multi-Phase Systems (prof. Poelma)

https://www.tudelft.nl/en/3me/organisation/organisation/departments/process-energy/

https://www.tudelft.nl/en/3me/organisation/organisation/departments/process-energy/

Biomass – what is it?

Definition (EU e.g.) (EU Directive 2009/28/EC):

The biodegradable fraction of products, waste and residues from biological origin from agriculture

(including vegetal and animal substances), forestry, and related industries including fisheries and

aquaculture, as well as the biodegradable fraction of industrial and municipal waste

Oil crops Sugar &starch crops

Lignocellulosic biomass

Biodegradable MSW, Sludges, manures

PhotosyntheticMicroorganisms

So…Biomass is?

Very diverse

Abundantly available

Linked with food/feed/fibre production

Non conventional (comp. to fossil), not an easy ‘plug-in’ energy vector

Requiring:

taylored harvesting/handling (transportation/storage)

widely differing processing technologies to arrive at suitable end products

Biomass utilisation strategy

Sustainability criteria to be met

Direct conversion of local/domestic biomass

(residues) in distributed plants into materials / heat & power

Upgrading of biomass into high-density fuels with favourable

logistic properties (solid: pelletisation,torrefaction;

liquid: pyrolysis; gas: gasification)

Utilizing these biomass fuels targeting triangle of

biomass based economy

Heat utilisation optimisation to achieve maximum

energy efficiency

Pharma &Fine Chemicals

Food & Feed

Chemicals & Materials

Transportation Fuels

Power & Heat

Market Volume

Van Krevelen Diagram depicting Coalification

book ‘Biomass as a sustainable energy source for the future’,Wiley, de Jong and van Ommen, 2015

Molecular Architecture of Wood Tissue


Cellulose

O

O O

OH

HO

OH

O

O

OH

HO

OH

O

OHO

OH

OH

HO

O

OH

OH nCellobiose unit

4 4

4

1

1

1

O

O

O

OH

O

O

O OH

H

O H

H

OHO

Cellulose is a linear

polymer of glucose,

crystalline structure

(some part in biomass

amorphous)

Degree of polymerization

~5000-15000


Hemicellulose(s)


Xylan is the dominant

hemicellulose in hardwood and

non-woody biomass. Amorphous

structure.

Degree of polymerization ~500-

1000

Other Polysaccharide Structures

compared to cellulose

O

OHO

OH

NH2O

OHO

OH

NH2

O

O

OHO

OH

NHOAcO

OHO

OH

NHOAc

O

O

OHO

OH

OH

O

O

OH

HO

OH

O

n

n

n

Chitin

Chitosan

Cellulose


Lignin

(C40H44O6)

• Aromatic

structure

• Binding

agent


Inorganic Matter in High-T Ashes

Vassilev et al. (2010) Fuel 89, pp. 913-33

Biomass conversion technologies


Gasification technologies

A division related to the way of heat input:

Indirect (allothermal)

Heat is introduced by heat exchange (e.g. heatpipes, external reactor wall)

Relatively expensive, limited in temperature

Product gas is not diluted

Direct (autothermal)

Steam/Oxygen/air (in different combinations) added, part of the biomass is combusted to generate heat.

High temperature possible

Product gas is diluted (particularly when using air)

Hybrid concepts

Gasification: process chemistry

Picture gasifier: https://www.ankurscientific.com/technology.html

Schematic: http://www.gasifier.in/faq.html

Gasification: process chemistry

and thermodynamics

Table: Huber, G.W., Iborra, S. and Corma, A. (2006) Chem.Rev. 106, pp. 4044-98

Not only simple small molecules are formed…tars

Small-scale gasifiers: fixed-bed reactors

Olofsson, I., A. Nordin, et al. (2005). Initial Review and Evaluation of Process Technologies and Systems Suitable for Cost-Efficient Medium-Scale Gasification for Biomass to Liquid Fuels. Umeå, Technical Report for University of Umeå, Umeå (Sweden)

Biomass enters in top Air/oxygen in bottomHigh tar content: ca. 100 g/Nm3

Mature technology for heat productionCan be used for small scale applicationsNo carbon in the ash

Biomass enters in top Air/oxygen in toplow tar content: ca. 1 g/Nm3;Ideal when clean gas is requiredLower overall thermal efficiencyDifficulties handling higher moisture and ash contents

Updraft Downdraft Crossdraft

Medium/large-scale: Fluidized bed reactors

Small/medium biomass particles

Air/oxygen in bottom

Biomass in bottom (usually)

Bed contains sand/other bed

material

Good for large scale applications

Medium tar yield (order of magn.

g/Nm3)

High particle loading in gas

Olofsson, I., A. Nordin, et al. (2005). Initial Review and Evaluation of Process Technologies and Systems Suitable for Cost-Efficient Medium-Scale Gasification for Biomass to Liquid Fuels. Umeå, Technical Report for University of Umeå, Umeå (Sweden).

BFB CFB

Hybrid FB

Entrained flow gasifiers

Oxidizer: Oxygen

High T (up to 1700 oC)

Ashes are molten

Developed for coal/oil

Low tar formation

Very small particles needed: pretreatment

Gasification technologies for biomass

and their scales

0.1 MW

1 MW

10 MW

100 MW

1000 MW

Downdraft fixed bed

Updraft fixed bed

BFB (atm./pres.) CFB (atm.)

CFB (pressurized)

Entrained flow

Hybrid FB

Important parameters for gasifier design

2

2

externalO supply/fuelsupply=

stoichiometricO requirement/unit of fuelinput (daf basis) Stoichiometric

Oxygen ratio

steam mass flowSB =

fuel feed rate

Steam toBiomass Ratio

m,C,residue

m,C,feed

CC = 1

CarbonConversion

m,i

m,fuel fuel

LHVCGE =

LHV

i

ColdGasEfficiency

Thermodynamic Equilibrium - gasification

Wood, 20 bar, 850oC Oxidizer: air

Kinetic rates of different biochars

C+H2O=CO + H2 reaction

Di Blasi, C. (2009). "Combustion and gasification rates of lignocellulosic chars." Progress in energy and combustion science 35(2): 121-140.

1 m 1 X

m t 1 X t

Cr

0

0

m mX

m m

t

TGA

Char gasification kinetics

XT c X

t

Xk X c

t

i

i

( , ) ( )

. .

char s

n

dR R

d

de g f

d

Khawam and Flanagan (2006). J.Phys.Chem.B 110(35), pp. 17315-28.

Value chains towards different products

Industrial example: Enerkem (Rotterdam)

gasification of waste to produce methanol

https://enerkem.com/about-us/technology/

Gas cleaning and upgrading steps for biomass

gasification in an industrial BtL chain

UtilizationStorage?

Tar, what is it?

In the end of the nineties (last century) long discussions in scientific community

(a.o. IEA, EU-FP5) ‘ending’ in:

Generic (unspecific) term for entity

of all organic compounds present

in the gasification product gas

excluding gaseous hydrocarbons

(C1 through C6)

What are the issues with tars?

Relatively low temperature gasifiers (FixB, [C]FB) cause tar issues

(next to gasification product gas losses):

Pipe blocking Process Equipment Fouling

ECN, website http://www.thersites.nl/

http://www.thersites.nl/

Methods for reducing tar concentration

levels during biomass gasification

Gas cleaning, particles:- Wet (scrubbers, oil/water)- Dry (cyclones & filters)

Another class of gasification technology:

Supercritical water gasification (SCWG)

• Drastic change in physical

properties of water under near-

critical water conditions

-> opportunity for salt separation

and tar-free gasification

Kamler, J., Andres, J., 2012. in: Yun, Y. (Ed.), Gasification for Practical Applications. InTech.

• Mid 80ies to 90ies: autoclave studies

– Kinetic studies of pure compounds (Antal USA e.g.)

– Blending studies and their impact on carbon conversion,

gas yields etc.

– Impact of reactor wall material on the reactions

(catalysis)

Development of SCWG technology

• Later development of continuously operating reactor technology• Tubular (plug flow) reactors (NL: Sparqle; DE: KIT with salt separation)

• Novel: fluidized bed reactor (China/Japan, NL: Delft/Gensos)

Process Concept SCWG

Matsumura Y., et al. (2005) Biomass Bioenergy;29:269–92.

Reactor

FactSage & SimuSage based model

main components

Case study, work-out in small groups

Waste gasification system, Enerkem BFB gasification technology

Per year:360 kton waste processed,220 kton methanol produced

- How many households (est.)?- What to do with the product?- Which markets?- What are the implications?- Which issues to you foresee in the

process chain? How to tackle?- Better alternatives?

Documents

Gasification · A. Nordin, et al. (2005). Initial Review and Evaluation of Process Technologies and Systems Suitable for Cost-Efficient Medium-Scale Gasification for Biomass to Liquid