the coal handbook: towards cleaner production || coal gasification and conversion

© Woodhead Publishing Limited, 2013

427

16 Coal gasification and conversion

D. J. HARRIS and D. G. ROBERTS, CSIRO Energy

Technology, Australia

DOI : 10.1533/9781782421177.3.427

Abstract : Coal is a valuable resource used as a source of energy all over the world. Most applications burn coal for small and large scale power generation, or use coal as a reductant in metallurgical applications. There is, however, the opportunity to use coal as an energy feedstock for the production of a range of fuels and chemicals as well as high-effi ciency electricity, via gasifi cation-based technologies or direct coal-to-liquids systems.

This chapter explores the technologies, applications, barriers and research challenges associated with gasifi cation and conversion of coal for the production of high effi ciency power, transport fuels, and chemicals. It considers some of the emerging technologies which aim to reduce costs and emissions associated with coal use. These technologies also offer integrated pathways to cost-effective CO2 capture from coal-based plant.

Key words : gasifi cation, coal-to-liquids, IGCC, CCS.

16.1 Introduction

Coal has been used as an energy source for more than two thousand years.

In modern times its use has been dominated by thermal power generation

in pulverised fuel (pf)-fi red combustion boilers and as a fuel and reduc-

tant in iron and steelmaking applications. Countries abundant in coal rely

on it heavily for domestic power generation: in Australia, about 78% of the

electricity generated comes from the combustion of black and brown coals

(Commonwealth of Australia, 2012). Gasifi cation technologies provide a

fl exible foundation for high-effi ciency, low emissions systems capable of sup-

porting coal conversion to a range of energy and chemical products.

16.1.1 Conversion of coal to energy and chemical products

There is considerable interest in addressing the issues regarding emissions

from coal use, in particular those of greenhouse gases (CO 2 in particular).

From a power generation perspective, this must start with effi ciency: most

of Australia’s installed coal capacity operates with thermal effi ciencies of,

428 The coal handbook


at best, 35–37% with many older installations and those operating on high

moisture coals operating at effi ciencies less than this. To meet the increasing

demand for power and increasingly stringent environmental requirements,

new technologies for power generation from coal must address cost, reli-

ability, by-product management challenges, and provide a high-effi ciency

technology platform to directly reduce CO 2 emissions intensity as well as

creating a path for commercially viable carbon capture and storage (CCS)

technologies which will inevitably be required for coal to maintain a strong

role in future power generation technology portfolios.

There is also the opportunity through coal-to-liquids conversion technol-

ogies (either direct liquefaction or indirect CtL via gasifi cation routes) to

use widely available reserves of black and brown coals to partially replace

imports of oil for the production of transport fuels.

Gasifi cation is a fl exible coal utilisation technology that can address both

of these concerns. Gasifi cation of coal is a process whereby coal is con-

verted to a syngas, which is predominately a mixture of carbon monoxide

and hydrogen. As shown schematically in Fig. 16.1, syngas is a precursor to

an extensive range of energy and chemical products: it can be combusted in

a combined cycle turbine system for effi cient production of electricity, fed

into a Fischer-Tropsch plant for the production of a range of liquid fuels,

reformed to methane to provide synthetic natural gas (SNG), converted to

Liquid fuels andhydrocarbons

SNG

CoalGasification

IGCCElectricitySyngas

Energydistribution?

Fuelcells

Methanol

MTG

Gasoline

Chemicals

Ammonia

Fertilisers

H2

Fischer-Tropsch

Directliquefaction

16.1 Some typical options for coal-derived products, either from direct

liquefaction or via gasifi cation for syngas production.

Coal gasifi cation and conversion 429


methanol and used to produce gasoline, or used as a precursor for the pro-

duction of a range of fertilisers, explosives and other chemicals.

The chemical processes that comprise gasifi cation are considerably dif-

ferent from those which occur in more traditional coal-combustion based

pf boilers. A fundamental difference is the oxygen to carbon ratios used: pf

systems typically operate with excess air, whereas gasifi cation systems use

signifi cantly lower oxygen:carbon ratios, and this stoichiometry is carefully

controlled to ensure that optimum gasifi cation conditions are present for

the specifi c fuel–technology combination. Consequently, the coal combus-

tion reactions have a minor role in the coal gasifi cation conversion process,

and the much slower, endothermic coal gasifi cation reactions with steam

and carbon dioxide dominate the conversion process.

These fundamental differences mean that the coal properties and indices

that are used to characterise fuel suitability for use in pf applications (and

which form specifi cation criteria for marketing purposes) are not relevant

to coal assessment for gasifi cation. As the physical and chemical reaction

processes that constitute the gasifi cation process are vastly different from

those found in coal combustion, a different set of fuel performance and

coal characterisation criteria are needed. Gasifi cation reactions are several

orders of magnitude slower than the combustion reactions, making their

impact on coal behaviour and gasifi er design more signifi cant. Some gasifi -

ers also require coal mineral matter to melt and fl ow out of the gasifi er as a

slag, which places particular requirements on the viscosity behaviour of the

Installed

4 × 104

3 × 104

2 × 104

Syn

gas

prod

uctio

n (M

Wth

)(eq

)

104

0Chemicals Fuels Power

Planned

16.2 Planned and installed coal gasifi cation plants for the production

of chemicals, fuels, and electricity. (Source: Data from Gasifi cation

Technologies Council, 2012.)



molten mineral matter (more details on coal properties required for specifi c

gasifi cation technologies are given in Section 16.3).

There is, however, considerable international experience in coal gasifi ca-

tion for a range of applications. Coal gasifi cation is an important part of the

global chemical industry, and plays a key role in the production of liquid

fuels. Gasifi cation for power generation is a growing industry (see Fig. 16.2)

and will be an important technology for reducing the greenhouse gas emis-

sions from coal-based power generation, as it provides a particularly suit-

able, high effi ciency platform for integrated CO 2 capture.

16.1.2 Coal gasifi cation for power generation

Integrated Gasifi cation Combined Cycle (IGCC) uses syngas from gasifi ca-

tion of coal (or mixtures of coal with biomass or other hydrocarbon mate-

rials such as petroleum coke), and integrates this with a combined-cycle

steam and gas turbine system for electricity generation. Integrating gasifi ca-

tion processes with combined cycle turbine systems for power generation is

relatively new: there are currently six commercial-scale coal-based IGCC

demonstration plants around the world.

Although none of the current dedicated IGCC plants capture and

store CO 2 , capture and storage of CO 2 produced from coal gasifi cation

for Synthetic Natural Gas (SNG) production is being demonstrated in

the US by the Dakota Gasifi cation Company. The CO 2 from this plant is

delivered by high pressure pipeline to the Weyburn CO 2 storage project

in Canada.

An IGCC plant consists of four main operating components:

1. an oxygen plant (current technologies use cryogenic air separation units

(ASU) although advanced, high effi ciency membrane based oxygen

plants are being developed and these have several promising attributes

for IGCC applications). Some plants use air rather than oxygen as the

gasifi cation medium. Air blown plants are less amenable to chemicals

production applications and to high levels of pre-combustion CO 2 cap-

ture than oxygen blown gasifi ers.

2. a gasifi cation plant – for converting solid or liquid hydrocarbon fuels

into synthesis gas (syngas)

3. a syngas gas clean-up system and

4. a combined cycle power plant.

The ASU separates the major components from air and supplies the gas-

ifi er with a stream of high pressure oxygen. The gasifi er reacts coal (or a

variety of hydrocarbon fuels) with this oxygen in a controlled manner to

produce syngas (principally CO and H 2 ). Syngas is then cleaned to remove



particulates and other potential pollutant species. Finally, syngas is burnt in

a high effi ciency combined cycle gas turbine plant which comprises a gas

turbine, steam turbine, generator and other supporting infrastructure. A

schematic of a typical IGCC process is shown Fig. 16.3, and the existing

coal-fi red IGCC demonstration plants are summarised in Table 16.1.

Table 16.1 Coal-fi red IGCC demonstration plants

Plant Location Output

(MWe)

Feedstock Gasifi er Operation

Tampa Electric

Polk Plant

Polk County, FL

USA

250 Bituminous

Coal and

Pet Coke

GE 1996–Present

ConocoPhillips

Wabash River

Plant

West Terre Haute,

IN USA

262 Bituminous

Coal and

Pet Coke

E-Gas ® 1995–Present

NUON/

Demkolec

Willem-

Alexander

Buggenum, The

Netherlands

253 Bituminous

Coal and

Biomass

Shell 1994–Present

ELCOGAS/

Puertollano

Puertollano,

Spain

318 Coal and

Petroleum

Coke

Prenfl o ® 1998–Present

CCP Nakoso, Japan 220 Bituminous

Coal

MHI 2007–Present

Vresova Czech Republic 350 Coal/lignite Lurgi,

Siemens

1996–Lurgi

2008–Siemens

Pulverised coaloxygen / steam

recycle char

Gasifier

Productgas

Gas cooler

Boiler

Electricity

Electricity

Gas turbine

Steam turbineBoilerfeed water

Hot gas cleaning (540–1000°C)

Fly slag,char forrecycle

S and N compoundsremoval

CombustorAirBoiler

feed waterQuenched

slag frit

Boilerfeed water

2 M

Pa

(20

ATM

)15

00–2

000°

C

16.3 Schematic representation of an IGCC power station using a high

pressure entrained-fl ow gasifi er (Harris and Patterson, 1995).



IGCC power generation effi ciencies are higher than those possible with

many supercritical (SC) pf power stations, and offer considerably more

opportunities for future increases from improvements in gasifi er and turbine

design, oxygen production technologies, syngas cleaning materials, water-gas

shift processes and CO 2 separation technologies. Furthermore, the effi ciency

penalties associated with CO 2 capture from gasifi cation-based plant are

already signifi cantly less than those applying to commercial post-combustion

CO 2 capture systems which can operate on fl ue gas streams from conven-

tional combustion power stations, making them particularly well suited as a

platform for power generation applications incorporating CCS.

The fi rst commercial scale IGCC plants were implemented during the

1990s in the USA and Europe. These projects followed the coincident

development of high pressure gasifi ers in the chemical and refi nery sector,

improvements in gas turbine technology and demands for improved envi-

ronmental performance of coal utilisation.

Further developments in gas turbine and gas clean-up technology, and

now the additional requirement for CO 2 reduction, suggest that IGCC

offers a fl exible technology platform with the potential for the supply of

energy to society through production of decarbonised electricity in parallel

with synthetic liquid fuels, fertilisers and chemicals from coal.

However, the deployment of IGCC to date has been limited by its rela-

tively high capital cost, some initial experiences where the early plants had

diffi culty meeting very high utility reliability standards, and a generally poor

understanding in the current utility industry of IGCC technology and its

potential. Clearly the costs of deploying new, high effi ciency plant and of

capturing and storing CO 2 are signifi cantly greater than those associated

with the deployment of mature conventional technologies. In many coun-

tries there are still no clear commercial drivers for signifi cant investment

in new-technology large power plants with high effi ciencies and lower CO 2

emissions or for the commercial deployment of large-scale CCS projects.

Given the potential for IGCC-based systems to meet increasing electricity

demands with a signifi cant reduction in CO 2 emissions, there is considerable

research and development around the world aimed at addressing the cost and

performance barriers of gasifi cation-based power generation technologies.

16.2 Conversion of coal to liquids and chemicals (CtL)

Coal gasifi cation-based processes for conversion of coal to liquid fuels

and chemicals have been in commercial operation for considerably longer

than gasifi cation for power generation. Methods for the conversion of coal

to liquid fuels (CtL) have been available since the 1930s, but widespread

acceptance of the technologies has been hindered by the availability of

cheaper petroleum resources. Major applications of the technologies for



coal conversion have typically been related to political isolation, such as

in Germany during World War II and in South Africa during the extended

period of political isolation. Despite the restricted applications of the tech-

nologies, substantial research efforts have been undertaken in numerous

countries in preparation for the eventual decline in petroleum availability.

In broad terms, conversion technologies appear to be fi nancially viable if

petroleum prices remain above US$ 35/bbl for the long term, but fi nancial

and technology risk factors have tended to delay investment while there is

the potential for petroleum crude prices to drop below US$ 70/bbl.

16.2.1 Direct CtL

Direct Coal Liquefaction (DCL) commonly refers to catalytic hydrogenation

of coal in a recycled oil solvent at high pressures with a catalyst. While a range

of process confi gurations have been proposed, the most common version

involves at least two high pressure slurry reactors in a series using a dispersed

iron-based catalyst and hydrogen supplied from a parallel gasifi cation system.

Typically, the liquefaction reactors operate at temperatures of up to 450 ° C and

pressures up to 200 bar with a 3-phase slurry of coal, recycle oil and hydrogen.

A major ambition in research is to achieve signifi cant cost savings by reducing

the intensity of these conditions in order to reduce the capital cost.

DCL is distinctly different in operation from the indirect processes. As

the coal is not gasifi ed, there is limited opportunity to remove impurities

and the products are related to the original structures in the coal. There are

considerable improvements in effi ciency in oil production compared to indi-

rect processes, but there is also more sensitivity to coal properties.

16.2.2 Indirect CtL

Indirect coal-to-liquids processes rely on the conversion of coal to syngas,

in the same manner as the IGCC power stations discussed earlier. Instead

of cleaning and combusting the syngas, however, indirect CtL processes use

the syngas in catalytic conversion processes to produce specifi c hydrocarbon

fuels. Coal properties, therefore, have less of an impact on the nature of the

liquid fuels produced, and are important from a gasifi cation perspective in the

same way as they are for IGCC or production of chemicals and fertilisers.

Fischer-Tropsch synthesis technologies have been used since the 1930s and

involve the use of a catalyst to convert synthesis gas mixtures (containing high

concentrations of carbon monoxide and hydrogen) into long chain hydrocar-

bons. Depending on the catalyst and operating conditions used there are differ-

ences in the length of the chains formed and the byproducts that can result.

Typically, the Low Temperature Fischer-Tropsch (LTFT) process will pro-

duce what is termed waxy crude, basically a mixture of long chain hydrocarbons



similar to paraffi n wax, as a raw product and this will then be hydrocracked to

reduce the chain lengths to suitable sizes for automotive fuels. The waxy crude

will contain some alcohols and olefi ns (unsaturated hydrocarbons), as well as

the major product of alkanes (paraffi ns), but these will be hydrogenated to

produce alkanes in the hydrocracker.

An alternative Fischer-Tropsch process, High Temperature Fischer-Tropsch

(HTFT), uses an iron-based catalyst to produce a range of hydrocarbons

directly suitable for automotive fuels. The higher temperature synthesis has

the advantage of producing a wider range of compound types, such as aromat-

ics, that improve the suitability of the product fuels for automotive use.

The methanol to gasoline (MTG) process uses a zeolite catalyst to spe-

cifi cally produce a range of hydrocarbons only in the LPG and gasoline size

ranges. The standard Exxon Mobil process consists of reforming, methanol

synthesis, methanol dehydration to dimethyl ether (DME) and gasoline syn-

thesis stages; however, Hald ø r-Topsoe have developed a lower cost version

of this that combines methanol synthesis and dehydration.

16.3 Gasification technologies

There is a variety of commercially-available gasifi cation technologies, each

being well suited to particular fuels and applications. These gasifi cation

technologies differ signifi cantly in their requirements for fuel preparation

and properties, pressures and temperatures of operation, nature and quality

of the syngas produced, effi ciencies of operation, scale of production, and

capital and operating costs. The main gasifi er technology variants are usu-

ally described in relation to the nature of the presentation of the fuel to the

gasifi cation media. The basic classifi cations are entrained fl ow, fl uidised bed,

or fi xed bed; although there are now technologies emerging, such as circulat-

ing fl uid-bed technologies, that operate near the boundaries of these sys-

tems and share features of these different types. The characteristic features of

these gasifi er technology types is described briefl y below. A detailed descrip-

tion of the leading processes and their commercial applications is provided

by Higman and van der Burgt in their comprehensive treatise on industrial

gasifi cation processes (Higman and van der Burgt, 2008). The IEA Clean

Coal Centre has also recently published excellent reviews on the commercial

technology confi gurations currently available from the leading gasifi cation

technology developers (Carpenter, 2008; Barnes, 2011; Mills, 2012).

16.3.1 Entrained fl ow gasifi ers

Entrained fl ow gasifi ers feed pulverised coal at high pressures into a gasifi er

where temperatures and pressures are high (up to, and possibly over 1800–

2000 K and 2.0–4.0 MPa) and residence times are low (up to 5 s). Due to



their high reaction rates, entrained fl ow gasifi ers offer high throughput and

conversion for a wide range of feedstocks, making them the most common

gasifi cation technology for large IGCC applications (Table 16.2).

The available commercial entrained fl ow gasifi cation technologies are

differentiated by particular combinations of feeding method and oxidant

type, gasifi er confi guration and construction material, and mode of syngas

quench. The impacts of these variations on fuel requirements and syngas

quality (and therefore suitability for downstream applications) means that

most technology vendors are continually exploring variants to their gasifi er

design and syngas-processing confi guration. For example, Shell now offers

a partial quench system and Siemens is developing a radiant syngas cooler

confi guration to suit specifi c applications.

Slurry-fed gasifi ers (such as the GE gasifi er) overcome issues associated

with feeding powdered solids into pressure vessels and can operate at very

high pressures; however, the increased reliability and decreased capital cost

comes at the expense of a greater oxygen demand due to the increased

thermal load. Refractory-lined gasifi ers (such as GE, Phillips 66 EGas) are

extremely fl exible in mineral matter content and properties of the feedstock,

but are more susceptible to ceramic liner erosion and corrosion than water-

wall (or membrane-lined) gasifi ers. Membrane-walled gasifi ers (such as

Shell and Siemens) require a protective slag layer to form, which is strongly

dependent on the properties of the coal used.

Two-stage gasifi ers (such as the MHI and Phillips 66 EGas gasifi ers) have

two coal injection points: one in the ‘combustion’ stage, where heat is gener-

ated to melt the mineral matter and to drive the gasifi cation reactions, and

one in the second stage, where coal and char are ‘gasifi ed’ using the heat and

gaseous products from the combustion stage. The second stage also serves

as a ‘chemical quench’, whereby the progress of the gasifi cation reactions

partially cools the syngas and stores this heat as chemical energy in the syn-

gas. They consequently have greater cold gas effi ciencies than single-stage

Table 16.2 Characteristics of the leading commercial goal gasifi cation

technologies

Technology Stages Oxidant Feed Confi guration Gasifi er wall

Shell, PRENFLO 1 O 2 Dry Up-fl ow Water-wall

GE 1 O 2 Slurry Down-fl ow Refractory

Conoco-Phillips E-Gas 2 O 2 Slurry Up-fl ow Refractory

MHI 2 Air Dry Up-fl ow Refractory

and Water-

wall

Siemens 1 O 2 Dry Down-fl ow Water-wall

Source: Harris and Roberts, 2010.



gasifi ers; however, this can be offset by higher rates of unconverted carbon

(and char recycle) and the possible production of some tar species (two-

stage gasifi ers often have a char-recycling capability, which increases the

total carbon conversion but also increases the capital cost).

Most entrained fl ow gasifi ers are oxygen-blown, as the presence of signif-

icant amounts of N 2 is detrimental to the downstream chemical production

processes for which most of these gasifi ers were designed. For oxygen-blown

gasifi cation, air is separated in an air-separation unit (ASU) and high purity

O 2 (usually over 90%) is used as the oxidant, usually with steam to manage

the temperature. There are signifi cant capital and operating costs associated

with operating an air-separation unit: the ASU can comprise up to 15% of

the capital cost of an IGCC plant, and consume up to 20% of the power

generated (Lowe et al ., 2008). The greater gas volumes associated with air-

blown gasifi cation, however, are also signifi cant: gasifi ers must be larger, and

downstream syngas cooling and cleaning plant must also be larger (Higman

and van der Burgt, 2008). For IGCC applications, therefore, there is a trade-

off between capital cost and operating cost and reliability.

The need for higher effi ciencies and lower cost for gasifi cation systems,

particularly for application in the power generation sector, is driving new

initiatives in gasifi er design. Several new technology variants have emerged

in recent years and these are at various stages of development and commer-

cialisation. Some of the leading examples are indicated below.

Pratt and Whitney Rocketdyne (PWR) is developing a high intensity, com-

pact gasifi cation technology aimed at signifi cantly reducing the size and cost

of commercial scale gasifi cation systems. The technology builds on PWR’s

rocket engine experience and comprises a high pressure dense phase dry

feed system with rapid mixing via multiple fuel injectors. The gasifi cation

reactions proceed in a high velocity plug fl ow tubular reaction zone with

advanced gasifi er wall cooling system. The technology is currently undergo-

ing pilot scale testing using an 18 ton/day test facility at the Gas Technology

Institute at Des Plaines, Illinois. Performance and design targets include

90% reduction in size and up to 50% reduction in cost of the gasifi er unit

(Darby, 2010).

Several commercial scale gasifi cation technology variants are now reach-

ing demonstration scale in China and these are expected to be deployed

in future coal to chemicals and liquid fuels plants which are undergoing

strong growth in China (Minchener, 2011). The most mature of these is

the ‘Opposed Multi-burner’ (OMB) gasifi er developed by the Institute of

Clean Coal Technology (ICCT) at the East China University of Science and

Technology. This gasifi er uses a coal-water slurry feed injected through four

opposed fi red burners at the top of the down-fl ow gasifi er unit. A dry-fed

variant is also under development. The gasifi er also uses an internal water

quench system which simplifi es slag removal and gas clean-up. The Huaneng



Clean Energy Research Institute (HCERI), formerly the Thermal Power

Research Institute (TPRI), has developed a 2-stage up-fl ow entrained fl ow

gasifi er which is part of the Chinese GreenGen project. Phase 1 of this proj-

ect is now under way and plans include operation of a 400 MW IGCC dem-

onstration project in 2015.

16.3.2 Fixed-bed gasifi ers

Fixed-bed gasifi ers (shown schematically in Figure 16.4) operate in a man-

ner similar to blast furnaces, where lump coal is fed from the top and oxygen

(and therefore heat) is supplied from the bottom. Solids residence times are

high and coal mineral matter is removed either dry (as in the SASOL-Lurgi

gasifi ers) or as a slag (as in the slagging British Gas-Lurgi technology).

Fixed-bed gasifi ers have specifi c requirements of coal properties: struc-

tural stability of the slowly moving bed of coal and char is important, as is

the ability for gas to permeate uniformly through the coal and char bed. The

relatively low throughput per unit, somewhat low degree of fuel fl exibility

and the tendency for the syngas to contain relatively high levels of tars make

Coal

Bunker

Feeder

Coallock Quench

liquor

Crude gas togas cooling

Steam

Waste heatboiler

Boiler feedwater

Quenchcooler

Rotatinggrate Stream and

oxygen

Ash lock

Ash to sluiceway

Gas liquor

16.4 The Sasol-Lurgi dry-bottom fi xed-bed gasifi cation technology (Van

Dyk et al ., 2004).



fi xed-bed gasifi ers generally better suited to applications such as chemicals,

SNG and liquid fuels production than for large-scale IGCC power genera-

tion applications.

16.3.3 Fluidised and circulating bed gasifi ers

A range of fl uid-bed processes have been used as the basis of gasifi cation

for syngas production. These gasifi ers involve the fl uidisation of a bed of

feedstock and ‘bed material’, often a mixture of coal ash and (possibly) a

calcium-based sorbent for in-bed capture of sulphur species. The coal feed

particle size (~1–3 mm) is smaller than fi xed-bed gasifi ers (10–50 mm), but

signifi cantly larger than entrained fl ow gasifi ers (< 200 μ m), and the tem-

peratures of operation are lower than entrained fl ow gasifi ers, typically 850–

900 ° C. This low temperature is required to ensure that the mineral matter in

the feed remains dry and does not become sticky, although agglomerating

fl uidised bed technologies operate at slightly higher temperatures in order

to remove the ash as large agglomerates. The lower operating temperatures

of fl uidised bed gasifi ers mean that high fuel reactivity is important, and

they may be particularly suitable for feedstocks with high levels of volatile

alkali species. Hence fl uidised beds are commonly used for biomass, lignite

and brown coal gasifi cation.

The method of fl uidising the bed varies between technologies, and gener-

ally the key variable is the velocity of fl uidising gas. Figure 16.5 demonstrates

this for three of the more common fl uidised bed approaches: stationary

Gas flowSolids flow

Stationary fluid bed

Vel

ocity

Circulating fluid bed Transport reactor

Increasing solidsdensity

Increasing expansion

Mean gas velocity

Mean solids velocity

Slipvelocity

16.5 Regimes of fl uid-bed operation (Higman and van der Burgt, 2008).



(and bubbling) fl uidised bed, where the bed and the gas above the bed form

two discrete phases; circulating fl uidised bed, where there is a considerable

degree of particle carryover and recirculation into the fl uidised bed; and the

transport gasifi er, which involves a high degree of entrainment and recircu-

lation of the bed material.

The deployment of large-scale fl uidised bed gasifi ers is not widespread

and most commercial units are small by power utility standards. There are

several fl uidised bed gasifi cation plants in Europe and Asia where they are

used primarily for conversion of biomass and waste material to syngas for

power generation or other applications. The 100 MW coal-fi red IGCC dem-

onstration project at Pi ñ on Pine in Nevada was based on a Kellogg Rust

Westinghouse agglomerating fl uidised bed gasifi er. At the time of its dem-

onstration, this plant was unable to be successfully operated under commer-

cial power industry reliability and availability requirements due to problems

with the reliability of the gas-cleaning plant and general integration issues

(Cargill et al ., 2001). The Transport Integrated Gasifi cation (TRIG TM ) tech-

nology is being developed by Southern Company and KBR, and several

commercial projects to demonstrate this technology are in development

(e.g. Pinkston and Salazar, 2007).

16.4 Coal properties and gasification performance

The range of gasifi er technologies discussed above leads to a spectrum of

fuel properties suitable for gasifi cation. These properties differ signifi cantly

between entrained fl ow, fi xed bed, and fl uidised bed gasifi ers. It is clear,

however, that traditional properties used to assess a coal’s suitability for use

in pf combustion applications are not suitable for assessing coals for use in

gasifi cation. Table 16.3 summarises some of the key coal properties that are

known to make particular feedstocks suitable for use in specifi c gasifi cation

technologies. Subsequent sections discuss these in more detail in the context

of specifi c gasifi er technology variants.

16.4.1 Coal properties suitable for entrained fl ow gasifi ers

The key fuel property for use in entrained fl ow gasifi cation is the ability of

the coal mineral matter to melt and fl ow out of the gasifi er as a liquid slag.

Measurements of the Ash Fusion Temperature (AFT) of ash can give some

insights into the temperature at which the mineral matter will soften and melt,

without providing important information regarding the viscosity and fl ow

behaviour of the slag. Measurements of slag viscosity are more suited to charac-

terising coal mineral matter in terms of its behaviour under entrained fl ow gas-

ifi cation conditions, and for quantifying the fl ux addition requirements, if any.

© W

oodhead P

ublis

hin

g L

imite

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Table 16.3 Summary of general coal requirements for use in specifi c coal gasifi cation technologies

Entrained fl ow Fluidised bed Fixed bed

Example Shell, GE, Siemens, MHI, Prenfl o High temperature Winkler, KBR

TRIG transport gasifi er

Sasol-Lurgi, British Gas-Lurgi

Coal Pulverised

For slurry feed low moisture or hydrophobic coals

preferred.

Crushed (0.5–5 mm), TRIG

fi ner. Often mixed with a

bed material to aid heat

transfer and to capture

S-species.

Lump (5–80 mm).

Optimal PSD to maintain

bed integrity.

Strong requirements of coal

caking and agglomerating

behaviour.

Reactivity High reactivity coals may be cheaper to run; most

fuels can be accommodated with appropriate

knowledge.

Lower operating temperature

means reactive coals, such

as sub-bit and lignite, are

favoured.

Can handle a range of

reactivities due to long

residence time, suited to

coals with ‘moderate’ to

‘high’ reactivity.

Ash

content

Refractory systems: less ash is better. Possible

issues with slag corrosion/erosion.

Non-refractory systems have a minimum ash

requirement to protect wall.

High AFT required to prevent

ash melting or sticking.

Agglomerating FBGs have

stringent requirements on

ash melting and softening

behaviour.

Dry-bottom gasifi ers have

similar requirements of

fl uidised bed gasifi ers.

Low ash content preferred;

dry bottom can

accommodate high ash.

Slag Slag fl ow with 25 Pa s or less at tapping

temperature. Tcv (temperature of critical

viscosity) less than operating temperature.

Ash softening and/or melting is

not desirable.

For slagging operation

requirements are similar

to that for entrained fl ow

gasifi cation; for dry-bottom

operation requirements are

similar to that for fl uidised

bed.

Source: Collot, 2002, 2006.



It is now generally considered that to be suitable for use in entrained

fl ow gasifi cation technologies, the acceptable range for slag viscosity of a

specifi c sample is 5–25 Pa s at a temperature of 1400–1450 ° C (Hurst et al ., 1999a; Hurst et al ., 1999b; Hurst et al ., 2000). Coals are sometimes fl uxed at

up to 10–20% by weight of ash in order to reduce the temperature required

to form a suitably viscous slag. There are, of course, economic and effi ciency

penalties associated with fl ux addition, meaning that accurate calculations

of fl ux requirements are important.

Whilst the inherent fuel fl exibility of entrained fl ow gasifi ers is high,

reactivity properties of fuels are important for ensuring proper gasifi er

design, and in optimising gasifi er performance during fuel switching or

blending activities. Reactivity is an all-encompassing term describing

the relative ease (and speed) with which a particular fuel can be con-

verted to syngas. It is used to describe a range of parameters, from fun-

damental kinetic expressions through to relative assessments of the rate

of conversion of different fuels under specifi c laboratory or gasifi cation

conditions.

The intense conditions found in entrained fl ow gasifi cation allow most

carbonaceous fuels to be gasifi ed, regardless of their reactivity. Highly reac-

tive fuels, however, require lower temperatures (and therefore reduced

oxygen consumption) with smaller gasifi ers to achieve satisfactory conver-

sion levels compared with less reactive fuels. This leads to a reduction in

capital and operating costs. Knowledge of coal reactivity under entrained

fl ow conditions is therefore important for gasifi er design, and in evaluating

the most suitable operating conditions for a specifi c coal. This requires an

understanding of two key aspects of coal reactivity for entrained fl ow gas-

ifi cation: volatile yields from devolatilisation, and the nature and reactivity

of the char produced.

Volatile yields under entrained fl ow gasifi cation conditions are often

different from the volatile matter assays returned from proximate analy-

sis (Roberts and Harris, 2003). Furthermore, this difference is dependent

on a range of competing variables, including coal type (Kochanek et al ., 2011). It is diffi cult to predict the volatile yield of a specifi c coal under a

particular combination of temperature, pressure, and heating rate, without

supporting laboratory measurements made under appropriate conditions

of temperature, pressure, and heating rate. Reactivity of the char pro-

duced from devolatilisation is known to be strongly dependent on a com-

bination of structure and intrinsic reactivity properties. By understanding

both of these aspects of char reactivity, accurate models can be developed

(Hla et al ., 2005) that relate coal properties to gasifi cation behaviour, and

ultimately how fuel variations can impact on gasifi er performance (see

later sections).



16.4.2 Coal properties suitable for fi xed and fl uidised bed gasifi ers

Fixed-bed gasifi ers operate with a fi xed or slowly moving bed of lump coal

(5–50 mm), through which the oxidant (and product) gases fl ow. This places

particular requirements on the structural and porous properties of the coal,

as the bed of fuel is required to be self-supporting whilst allowing the reac-

tants and products to permeate. Reactivity requirements are, generally, sec-

ondary, as the particles have long residence times (up to an hour) usually

allowing for good conversion of a range of coals.

The implications for coal requirements in slagging fi xed-bed gasifi ers are

similar to those for entrained fl ow gasifi cation: the mineral matter must

melt and fl ow out of the gasifi er as a molten slag. In this context, require-

ments are similar to those of a blast furnace. Conversely, dry-bottom fi xed

bed gasifi ers have similar requirements of the mineral matter to con-

ventional pf combustion systems, where the ash should not melt or form

agglomerates.

Fluidised bed gasifi ers operate at intermediate temperatures, low enough

to prevent the softening and melting of the coal mineral matter, but high

enough to achieve satisfactory conversion levels. The low temperatures (rel-

ative to entrained fl ow gasifi cation) mean that fl uidised bed gasifi cation is

particularly suitable for high-reactivity coals, which can achieve good con-

version in residence times of up to a few minutes.

16.5 Tools for gasification performance assessment

It is clear from the descriptions in the previous sections that there are no

readily-determinable coal properties that can be used for routine assessment

of a fuel for use in the variety of gasifi cation technologies in use and under

development. We do know, however, that our understanding of coal perfor-

mance in combustion systems (such as pf boilers) cannot be used directly to

make an assessment of the suitability of coals for use in gasifi cation. In order

to estimate coal suitability for use in gasifi cation-based systems, we need to

have models based on sound experimental data that accurately refl ect coal

behaviour under the wide range of conditions present in the different gasifi -

cation technologies. The development and application of these models need

to be supported by a practical coal test procedure, which can assess the key

stages of the conversion of coal in a gasifi er – in particular those stages that

affect the operation of specifi c gasifi er technologies allowing the differentia-

tion of coal performance under gasifi cation conditions.

Perhaps the most defi nitive of the coal properties is the behaviour of

the mineral matter, in particular its ability to fl ow at temperatures that are

suitable for entrained fl ow and slagging fi xed bed technologies, or for its



tendency to agglomerate or foul surfaces in fl uidised bed or dry-bottom

fi xed-bed gasifi ers.

The ash fusion temperature (AFT) is a common analysis performed on a

coal sample as part of its routine characterisation, and can be a useful indi-

cator of the general suitability of a specifi c coal for entrained fl ow gasifi ca-

tion. The AFT, however, is unable to provide information regarding the fl ow

characteristics of the coal’s molten slag; therefore more advanced techniques

are required for coal assessment and gasifi er operation optimisation.

Facilities exist for the measurement of coal slag viscosities at entrained

fl ow gasifi cation temperatures, and accompanying models are able to opti-

mise potential coal blends or fl ux addition requirements (e.g. Patterson et al ., 1998; Hurst et al ., 1999a; Hurst et al ., 1999b; Patterson and Hurst, 2000). As

noted above, to be suitable for use in entrained fl ow gasifi cation technolo-

gies, the maximum limit for slag viscosity is about 25 Pa s (ideally under 15

Pa s) at a temperature of 1400–1450 ° C (Patterson et al ., 1998). By analysing

the composition of the mineral matter, comparing this composition to

known samples, and by making measurements of slag viscosity behaviour,

the potential suitability of a specifi c sample from a slag behaviour perspec-

tive can be assessed. Furthermore, if a coal sample has mineral matter that

does not perform satisfactorily, then blending or fl uxing strategies can be

developed (see Fig. 16.6).

Studies of mineral matter suitability are supported by laboratory and

technical scale measurements of specifi c aspects of the coal conversion pro-

cess. Of particular signifi cance are the amount and nature of the char pro-

duced from devolatilisation, and how fast this char is converted to syngas

(Fig. 16.7). Using laboratory-scale facilities (e.g. Harris et al ., 1999) reliable,

transportable data are able to be generated that refl ect important aspects of

coal conversion behaviour under gasifi cation conditions (Harris et al ., 2003;

Kajitani et al ., 2006).

A key aspect of these studies is the ability to interrogate the gasifi ca-

tion process under conditions relevant to entrained fl ow gasifi cation, using

laboratory-scale, high pressure, entrained fl ow facilities (e.g. Fig. 16.8). Such

facilities allow the temporal resolution of the coal and char gasifi cation pro-

cess over a range of temperatures, pressures, and O:C ratios. This provides

unique and important insights into the impact of coal type and operating

conditions on coal behaviour under gasifi cation conditions (e.g. Figs 16.9

and 16.10) and provide insights into the chemical and physical reaction

processes that lead to these differences (e.g. Figs 16.11 and 16.12). Along

with the slag formation and fl ow issues discussed above, this knowledge is

able to be linked with operating strategies of pilot-scale gasifi cation systems

(Roberts et al ., 2012a, 2012b).

To allow regular and reliable application of a sound fundamental under-

standing of gasifi cation science to the solving of real industrial problems,



40

30

20

Vis

cosi

ty (

Pa.

s)

10

013001200 1400

100/20Ash/CaCO3

Bulk sampleCoal B

100/10 100/0

ExperimentalPredicted

Experimental

Coal ash A

Ash/CaCO3100/75 100/50 100/25

100/100

Predicted

1500Temperature (°C)

1600

40

30

20

Vis

cosi

ty (

Pa.

s)

10

013001200 1400 1500

Temperature (°C)1600

40

30

20

Vis

cosi

ty (

Pa.

s)

10

013001200 1400 1500

Temperature (°C)1600

Tcv

Experimental

S102 Coal ash

Predicted

16.6 Slag viscosity measurements at different temperatures,

demonstrating the impact of fl ux addition (Patterson and Hurst, 2000).



knowledge of coal pyrolysis, char formation, char reactivity, slag formation

and fl ow, and coal gasifi cation behaviour needs to be integrated in a form

that is applicable to a range of gasifi cation technologies and, eventually, gas-

ifi cation-based energy systems. The fundamental, experimental gasifi cation

research in Australia has always been undertaken in parallel with the devel-

opment of mechanistic models designed to allow more widespread applica-

tion of the outcomes.

Work by Shan et al. (Shan, 2000) and Liu et al. (Liu et al ., 2000) mod-

elled coal devolatilisation and char reactivity, respectively, under the high

pressures relevant to entrained fl ow gasifi cation technologies. Hla et al . (Hla

et al ., 2005; Hla et al ., 2006) integrated these models into an overall one-

dimensional gasifi cation model that was able to describe well gasifi cation

measurements made in research reactors such as the entrained fl ow reactor

in Fig. 16.8. Application of these gasifi cation models to the complex fl ow

systems present in industrial-scale gasifi ers (Hla et al ., 2011) allows impacts

of feedstock variation and operating parameters to be estimated (Figs 16.13

and 16.14).

By integrating these performance models with our understanding of slag

formation and fl ow behaviour, we can begin to understand the implications

of variations in feedstock quality, operating conditions, etc. on the perfor-

mance of a gasifi er and, ultimately, the performance of gasifi cation-based

systems for the production of power or other products. This requires the

integration of the fundamentally-based gasifi cation and gasifi er models

Pyrolysis

Heterogeneouschar-gas reaction

Volatile evolution

Char combustionO2

CO/CO2

CO2 and H2O

CO + H2

Char gasification

Ash and slag formation

16.7 A schematic of the coal conversion process. (Source: After Harris

and Patterson, 1995.)



discussed here with process simulation tools. Whilst there exists a large

number of studies in the literature whereby process modelling approaches

are used to compare different technology combinations, those using gas-

ifi cation as an enabling technology are not able to differentiate based on

Gas analysis

Feeder, 1–5 kg/hrParticle size–180+45 μm

Preheating and mixing(O

2, N2, H2O, and CO2)

Three-section reaction zone: temperatures upto 1500°C, residence times 0.5–3.0 s

Oil-cooled isokinetic sampling probeand gas analysis system

Water quench

16.8 CSIRO’s high pressure entrained fl ow gasifi cation reactor, for

studying details of coal gasifi cation behaviour under gasifi cation

conditions (Harris et al ., 2006).



coal reactivity, conversion, or slag behaviour. This has fl ow-on effects for the

development of tools to support a transition to the next generation of power

and fuels production systems in Australia and around the world: gasifi cation

with effi cient, large-scale carbon capture.

16.6 Gasification as a route to efficient carbon capture

Capturing CO 2 from coal-fi red plant will impact on the capacity and effi ciency

regardless of the platform technology. The nature of gasifi cation-based pro-

cesses, however, mean that this impact is signifi cantly less than for technologies

which have not integrated the carbon capture step with the process scheme.

Carbon capture is estimated to decrease overall conversion effi ciency by

more than 6 % points and to increase capital cost by up to 40%. As with

×× ×× × ×

+

+

+

+ +

+

+++

+ +++

×× ××

×

×

50(a)

(b)

CRC297

95965

CRC252

CRC272

CRC283

CRC263

CRC240

CRC296

CRC298

CRC274

CRC310

CRC284

CRC299

CRC281

CRC252

CRC263

CRC298

CRC274

CRC299

CRC358

CRC281

40

30

Gas

ifica

tion

effic

ienc

y (%

)G

asifi

catio

n ef

ficie

ncy

(%)

20

10

0

00 50 100

O:C Stoichiometry (%)

150 200 250

20

40

60

80

+

16.9 Effects of O:C ratio on gasifi cation effi ciency at 20 bar pressure

and (a) 1100 ° C and (b) 1400 ° C for a wide range of Australian coals

(Harris et al ., 2006).



the main IGCC plant, substantial improvements to the CCS process com-

ponents can be envisaged and development of these would substantially

reduce the cost and effi ciency penalties associated with CCS as part of a

gasifi cation-based system.

+

+

++

++

××××

×

××

××

×

×

×

××

×

××

100(a)

80 Char conversion CRC274

CRC310

CRC299

CRC358

CRC281

CRC252

CRC274

CRC298

CRC263

CRC358

Pet coke

Vol

atile

rel

ease

60

40

20

0

100(b)

80

60

40

20

00.0 0.5 1.0 1.5 2.0

Residence time (s)

Car

bon

conv

ersi

on (

%)

Car

bon

conv

ersi

on (

%)

2.5 3.0

16.10 Effects of temperature (a) 1100 ° C and (b) 1400 ° C and coal type on

conversion at 20 bar pressure and an O:C of ~1:1 (Harris et al ., 2006).

100

80

CRC252 CRC272 CRC2811673 K1573 K1473 K1373 K1273 K

Sub bit, high vol Bituminous Semi anthracite

60

40

20

00.0 0.5 1.0 1.5 2.0 0.0 0.5 1.0 1.5 2.0 0.0 0.5 1.0 1.5

Residence time (s)Residence time (s)

Cha

r co

nver

sion

(%

)

Residence time (s)2.0 2.5 3.0

16.11 Impacts of char structure on high temperature gasifi cation

reaction rates. (Source: After Roberts et al ., 2010.)



Regardless of the application, syngas produced from gasifi cation requires

treatment to remove solid and gaseous impurities and to prepare the gas

stream for subsequent processes, whether they be thermal (e.g. gas tur-

bine) or chemical (e.g. Fisher-Tropsch catalytic conversion to fuels) systems.

Gasifi cation-based chemical processes have proven and well-developed

solvent-based systems to remove sulphur and other acid gases such as CO 2

from the syngas prior to conversion to the desired product. Common com-

mercial solutions are based on the Rectisol and Selexol processes, which

have been extensively proven in a range of applications.

First-generation IGCC-CCS systems (i.e. IGCC with carbon capture) use this

proven solvent technology for integrated capture of CO 2 as part of the process

scheme, with the resulting H 2 -rich gas used in H 2 turbines for power genera-

tion. A typical commercial gasifi cation-based hydrogen and CO 2 production

2

CRC252 CRC272 CRC2810

–2

–4

–6

1673 K1573 K1473 K1373 K1273 KFBR dataRegime 2Regime 1

–8

–10

–12

–140.0005 0.0006 0.0007 0.0008

1/temperature (1/K) 1/temperature (1/K) 1/temperature (1/K)

0.0009 0.0005 0.0006 0.0007 0.0008 0.0009 0.0005 0.0006 0.0007 0.0008 0.0009 0.0010

16.12 High temperature gasifi cation reaction rates, demonstrating

the transition from ‘intrinsic’ reactivity conditions to those at higher

temperatures where pore diffusion limitations are signifi cant. (Source:

After Roberts et al ., 2010.)

60CRC701CRC702CRC703CRC704

90

85

80

80

75

70

CG

E (

%)

65

50

40

30

20

Gas

com

posi

tion

(vol

%)

10

01.0 1.1 1.2 1.3 1.4 1.5 1.6 0.9 1.0 1.1 1.2

Stoichiometry (O:C ratio)

1.3 1.4 1.5 1.6Stoichiometry (O:C ratio)

16.13 Example of the use of gasifi cation models to understand the

impact of coal properties on gasifi er performance (Hla et al ., 2011).

Here, CGE = ‘cold gas effi ciency’, an indicator of the relative effi ciency

of the performance of the gasifi er in converting energy in the feed to

energy in the syngas.



process is shown in the upper schematic of Fig. 16.15. Hot syngas leaving the

gasifi er unit is cooled (often using a wet quench) before it is cleaned of gas-

eous and particulate impurities. The clean syngas is then reacted with addi-

tional steam in a multi-stage shift reactor to convert CO to CO 2 and to produce

7

6

5

4

Gas

ifier

hei

ght (

m)

Gas

ifier

hei

ght (

m)

3

2

1

00.000

7

6

5

4

3

2

1

00.000 0.020 0.040 0.060 0.0800.005 0.010

Liquid slag thickness (m)Gas temp.

(°C)

Solid slag thickness (m)0.015

Benyon Seggiani Benyon Seggiani

16.14 Model simulations of gas temperature and slag thickness on the

wall of the ELCOGAS Prenfl o gasifi er (Benyon et al ., 2001).

Gasifier

Coal

CO+H2

CO + H2O = CO2 + H2

CO2+H2 H2

CO2

H2

CO2

Gascleaner

High Tshift

Membrane shifter

Coal

Mem

bran

ere

acto

r

Cur

rent

tech

nolo

gy

Low Tshift

Gas separation

16.15 Conventional and prospective syngas cleaning, processing and

gas separation technologies for CO 2 capture from large-scale hydrogen-

based energy systems.



additional hydrogen. This is an exothermic process and requires staged cooling

to maintain catalyst activity and appropriate conversion yields. The CO 2 /H 2 gas

mixture is then separated, often using solvents or pressure swing adsorption

processes to produce pure CO 2 and hydrogen product streams.

The need for a multi-stage process with multiple heating and cooling

cycles adds complexity and cost (both in capital and operating) and reduces

the thermal effi ciency of the process. Whilst technically mature and well-

demonstrated, there is the opportunity to decrease capital and operating

costs for more widespread application in the power industry through the

development of new gas separation systems involving high temperature

water-gas shift catalysts, membrane-based systems for separating CO 2 and

H 2 , and the integration of these multi-stage unit processes into a single ‘cat-

alytic membrane reactor’, or CMR.

Current research efforts are addressing each of the critical steps in the

technology chain illustrated in Fig. 16.15 with the aim of developing simpli-

fi ed, integrated syngas processing technologies as indicated conceptually in

the lower diagram in Fig. 16.15.

Alloy membranes offer a solution to the challenge of large-scale, cost-

effective separation of CO 2 and H 2 as part of the next generation gas

1e-7

9e-8

8e-8

7e-8

6e-8

V-Ni-Pd

V-Ti-Ni

V85Ni15

Pd75Ag25

Pd

a-Ni42Nb28Zr30

V-Ni-Al

5e-8

4e-8

Per

mea

bilit

y (m

ol m

–1 s

–1 P

a–0.

5 )

3e-8

2e-8

1e-8

0280 300 320 340

Temperature (°C)360 380 400 420

16.16 Hydrogen permeability of different alloy materials, compared

with the ‘benchmark’ of palladium. (Source: After Dolan et al ., 2011.)



separation systems (Dolan et al ., 2006; Dolan et al ., 2009). By seeking alter-

native materials to expensive palladium, and addressing issues of durability,

membranes that meet the US DoE performance targets can be manufac-

tured which are infi nitely selective to hydrogen and can be operated at

temperatures suitable for gasifi cation-derived syngas processing. By alloy-

ing vanadium, titanium and nickel, crystalline membranes with permeabili-

ties orders of magnitude greater than those for palladium membranes can

be manufactured (Fig. 16.16). There is also the option of using amorphous

materials (lower dataset in Fig. 16.16) which offer slightly reduced perme-

abilities but with signifi cant savings in cost.

Combining membrane materials such as these with water-gas shift reac-

tion catalysts, it is possible to continuously (and with 100% selectivity)

remove H 2 from the process using a catalytic membrane reactor (CMR).

Such systems allow greater-than-equilibrium conversion of syngas to sepa-

rate streams of CO 2 and H 2 in a single process step. This has the potential to

replace the high and low-temperature water-gas shift process, and the sol-

vent extraction and regeneration processes, with a single reactor unit offer-

ing a considerable decrease in both capital and operating costs.

It is important to ensure that gasifi cation-based technologies such as

IGCC are considered a part of the ‘CCS’ solution to ongoing coal use in a

carbon-constrained world. Whilst they do require investment in plant which

has not traditionally been used in the power generation sector, and which

has associated with it increased costs and perceptions of risk, this chapter has

shown that, from an international perspective, there is a signifi cant amount

of operating experience with coal gasifi ers. These technologies have also

been demonstrated at a commercial scale for power generation. Ongoing

research and development activities around the world are addressing issues

regarding cost and risk in terms of gasifi er design and operation, as well as in

advanced technologies for effi cient and cost-effective carbon capture.

16.7 References Barnes, I. (2011) Next generation coal gasifi cation technology , Report Number

CCC/187 IEA Clean Coal Centre.

Benyon, P., Boyd, R. and Lowe, A. (2001) Engineering Applications of Gasifi er Data-Gasifi er Simulations , Cooperative Research Centre for Black Coal Utilisation,

Commonwealth of Australia, CRC Research Report 29.

Cargill, P., DeJonghe, G., Howsley, T., Lawson, B., Leighton, L. and Woodward, M.

(2001) Pinon Pine IGCC Project – Final Technical Report to the Department of Energy , DOE Award Number DE-FC21-92MC29309.

Carpenter, A. M. (2008) Polygeneration from Coal , Report Number 978-92-9029-

458-0 IEA Clean Coal Centre.

Collot, A. G. (2002) Matching gasifi ers to coals , IEA Coal Research Report CCC/65

IEA Coal Research.



Collot, A. G. (2006). Matching gasifi cation technologies to coal properties.

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14–8.

Darby, A. (2010) In Gasifi cation Technologies Conference , Gasifi cation Technologies

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(2006) Review: Composition and operation of hydrogen-selective amorphous

alloy membranes. Journal of Membrane Science, 285 , 30–55.

Dolan, M. D., Dave, N. C., Morpeth, L. D., Donelson, R., Kellam, M., Liang, D. and

Song, S. (2009) Ni-based amorphous alloy membranes for hydrogen separation

at 400 ° C. Journal of Membrane Science, 326 , 549–555.

Dolan, M. D., Song, G., Liang, D., Kellam, M. E., Chandra, D. and Lamb, J. (2011)

Hydrogen transport through V 85 Ni 10 M 5 alloy membranes. Journal of Membrane Science, 373 , 14–19.

Gasifi cation Technologies Council (2012) http://www.gasifi cation.org/database1/

search.aspx. Accessed October 2012.

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Power Generation Technologies. Australian Institute of Energy News Journal, 13 , 22–32.

Harris, D. J. and Roberts, D. G. (2010) ANLEC R&D Scoping Study: Black Coal IGCC , CSIRO Report EP103810 CSIRO Energy Technology.

Harris, D. J., Roberts, D. G. and Henderson, D. G. (2003) Gasifi cation Behaviour of Australian Coals , ACARP Project C9066, Final Report (ET/IR 630R) CRC for

Coal in Sustainable Development.

Harris, D. J., Roberts, D. G. and Henderson, D. G. (2006) Gasifi cation behaviour of

Australian coals at high temperature and pressure. Fuel , 85 , 134–142.

Harris, D. J., Roberts, D. G., Mill, C. J., Kelly, M. D., Otake, Y. and Wall, T. F. (1999)

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for ACARP Project C6052 CRC for Black Coal Utilisation, August 1999.

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Burlington, MA.

Hla, S. S., Harris, D. J. and Roberts, D. G. (2005) A coal conversion model for interpre-

tation and application of gasifi cation reactivity data. International Conference on Coal Science and Technology , Okinawa, Japan.

Hla, S. S., Harris, D. J. and Roberts, D. G. (2006) CFD modelling for an entrained fl ow

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Entrained Flow Gasifi cation: Impacts of Coal Type on Gasifi er Performance.

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1831–1840.

Hurst, H. J., Novak, F. and Patterson, J. H. (1999b) Viscosity measurements and

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Hurst, H. J., Patterson, J. H. and Quintanar, A. (2000) Viscosity measurements and

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nous coals for use in slagging gasifi ers. Fuel , 79 , 1671–1678.

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Roberts, D. G. and Harris, D. J. (2003) The Role of Bench-Scale Reactivity Data in

the Assessment of Coals for use in Gasifi cation. 12th International Conference on Coal Science , Cairns, Queensland, Australia, 2–6 November 2003.

Roberts, D. G., Hodge, E. M., Harris, D. J. and Stubington, J. F. (2010) Kinetics of Char

Gasifi cation with CO2 under Regime II Conditions: Effects of Temperature,

Reactant, and Total Pressure. Energy and Fuels , 24 , 5300–5308.

Roberts, D. G., Ilyushechkin, A. Y. and Harris, D. J. (2012a) Linking Laboratory

Data with Pilot-Scale Coal Gasifi cation Performance. Part 1: Laboratory

Characterisation. Fuel Processing Technology , 94 , 86–93.

Roberts, D. G., Ilyushechkin, A. Y., Tremel, A. and Harris, D. J. (2012b) Linking

Laboratory Data with Pilot-Scale Coal Gasifi cation Performance. Part 2: Pilot-

Scale Testing. Fuel Processing Technology , 94 , 26–33.

Shan, G. (2000) A Comprehensive Model for Coal Devolatilisation. PhD Thesis,

University of Newcastle.

Van Dyk, J. C., Keyser, M. J. and Coertzen, M. (2004) SASOL’s Unique Position

in Syngas Production from South African Coal Sources using SASOL-Lurgi

Fixed Bed Dry Bottom Gasifi ers. 21st Annual International Pittsburgh Coal Conference , Osaka, Japan.

the coal handbook: towards cleaner production || coal gasification and conversion

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