ACARP ACARP ACARP ACARP
Low Emission Coal Use

Gasification of Australian Coals

Low Emission Coal Use » Low Emission Coal Use

Published: January 10Project Number: C17060B

Get ReportAuthor: Daniel Roberts, Alex Ilyushechkin, Alexander Tremel*, Peter Beavis, Mark Kochanek, David Harris | CSIRO Energy Technology, *Department of Energy Systems, Technical University of M√ľnich

Four Australian coals were trialled in the Siemens 5 MWth pilot scale gasifier in Freiberg, Germany, in August 2007. A summary report of these trials was issued by the former CCSD, which gave an overview of the results of the trials and some preliminary links between existing, laboratory-scale gasification data and coal behaviour under pilot-scale conditions. This report provides a more detailed analysis and interpretation of these gasification trials, as well as providing analysis and characterisation of process streams from the gasifier (in particular feed coals, slags, and other process solids).

 

Whilst all coals achieved similar ranges of conversion over the conditions used, there was some differentiation of the coals in terms of cold gas efficiency and in terms of the O:C ratio required to achieve suitable slag formation and conversion. The slag behaviour of the coals varied from poor to excellent.

 

These differences in conversion and slag behaviour were consistent with our expectation of coal behaviour based on characterisation using laboratory facilities (e.g. Pressurised Entrained Flow Reactor, slag viscometer, etc). These consistencies demonstrate the relevance of the suite of 'coal test procedures' developed to date as tools for estimating the performance of coals under entrained flow gasification conditions.

 

Model estimates and measurements of slag viscosity behaviour of slags made from the coals in the laboratory were shown to be good indicators of the potential slag flow behaviour under entrained flow gasification conditions. One exception to this was the fluxed coal sample-the fluxed mineral matter for this coal did not melt and flow to the extent suggested by the laboratory tests. Analysis of the structure of the chars made from this coal, however, suggest that this is related to the dense, closed nature of chars formed, which prevents interaction of the mineral matter and the slag under entrained flow conditions.

 

Coals that had good volatile yields and char reactivities in laboratory studies, with high conversion and good gas quality as indicated by PEFR tests, were easier to gasify than those that had low volatile yields and poor char reactivity. This meant that they could achieve good conversion levels at relatively low temperatures, leading to good cold gas efficiencies. The results of the trials, however, demonstrated the importance of considering conversion properties and slag behaviour properties in combination when assessing the potential gasification behaviour of a coal. Good 'reactivity' coals with mineral matter that requires a high temperature to melt and flow will not produce good quality syngas compared with a coal that has good 'reactivity' properties and mineral matter that melts and flows at low temperatures. These interactions were evident from the cold gas efficiency of the two 'best' coals (in terms of their conversion reactivity) but which differed significantly in the temperature required for good slag behaviour.  

 

Another valuable aspect of trialling coals in a pilot scale gasifier is the access to realistic process streams. Samples of slag and 'process water solids' (solids that were removed from the gas by the quench water spray) were collected from each set of conditions. The process water solids are essentially fly ash (coal mineral matter that has not melted) and 'fly slag' (mineral matter that has melted but not deposited on the wall of the gasifier), containing unconverted carbon in accordance with the conversion efficiency of the coal.

 

It was shown that the composition of the mineral matter of the feed coal is not necessarily consistent with the composition of the process water solids or the slag formed on the wall of the gasifier. There is a degree of partitioning of mineral matter components between the fly ash and the slag; there is also the potential to have the composition of the slag formed altered by the slag deposited form previous feeds to the gasifier. These changes in composition have been shown to be significant enough to alter the viscosity behaviour of the slag tapped from the gasifier, and therefore should be considered when assessing the potential of a coal's mineral matter for use in slagging gasifiers.

 

Key goals of the gasification trials campaign were to provide access to realistic samples of slag and process solids, and to provide the means by which data and knowledge from existing (laboratory-based) tools and techniques could be applied and tested against realistic gasification data. The work presented in this report clearly achieves these goals by providing new insights into coal conversion to syngas and slag, and by clearly demonstrating the relevance of laboratory and PEFR studies of coal gasification performance to our understanding of coal behaviour under entrained flow gasification conditions.

Underground

Health and safety, productivity and environment initiatives.

Recently Completed Projects

C25060Development Of Borehole Shear Monitoring Device For Routine Application In Coal Mine Roadways

This project outlines the development of a cost effective, routine s...

C26063Reliable Estimation Of Horizontal Stress Magnitudes From Borehole Breakout Data

The main objective of the project is to develop a reliable and simpl...

C26053Predict Stress State And Geotechnical Conditions Near Major Geological Structures Using Microseismic Technology And Distinct Element Modelling

Stress state and geotechnical conditions often change significantly ...

Underground

Open Cut

Safety, productivity and the right to operate are priorities for open cut mine research.

Recently Completed Projects

C25031Developing Closure Criteria For River Diversions: An Alternative To Reference Sites

The use of reference sites for establishing closure criteria in area...

C26034Coking Properties Deterioration In Small Samples

Accurate evaluation of coking coal parameters at the exploration sta...

C23029Alternative And Sustainable Explosive Formulations To Eliminate Nitrogen Oxide Emissions

This technical report describes the technology of a novel mining exp...

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

Recently Completed Projects

C250083D Flotation Of Fine Particles

In this project a process for the continuous, selective agglomeratio...

C26009Improved Precision Of Determining Coal In Urban Dust

Dust samples collected in coastal locations using High Volume Air Sa...

C25014Plant Scale Testing Of Safe Aerosol Frother Addition To Reduce Residual Frother And Reagent Costs

The use of frothers in the froth flotation process is essential in ...

Coal Preparation

Technical Market Support

Market acceptance and emphasising the advantages of Australian coals.

Recently Completed Projects

C26044Physical And Chemical Interactions Occurring During Cokemaking And Their Influence On Coke Strength

This project builds onto a previous project , C24055 in which macera...

C27056Imaging Gas Penetration Inside Coals And Cokes And Determining Influence On Coke Reactivity

The suitability of cokes for use in a blast furnace is determined by...

C26045Mineralogy Effects On The 3D Porosity Evolution Of Coke And Coke Reactivity

CRI/CSR CO2 combustion data are key metrics of coke quality and perf...

Technical Market Support

Mine Site Greenhouse Gas Mitigation

Mitigating greenhouse gas emissions from the production of coal.

Recently Completed Projects

C27058Technological Assessment Of A Recycle Reactor For VAM Abatement

Underground coal mining emits high volumes of methane, diluted in ve...

C27008Selective Absorption Of Methane By Ionic Liquids

The connection of a ventilation air methane (VAM) abatement plant di...

C24061Proof-Of-Concept Photocatalytic Destruction Of Methane For Coal Mining Fugitive Emissions Abatement

Australia's fugitive emissions in 2015 were 41 Mt CO2-e (representin...

Mine Site Greenhouse Gas Mitigation

Low Emission Coal Use

Step-change technologies aimed at reducing greenhouse gas emissions.

Recently Completed Projects

C17060BGasification Of Australian Coals

Four Australian coals were trialled in the Siemens 5 MWth pilot scale ga...

C17060AOxyfuel Technology For Carbon Capture And Storage Critical Clean Coal Technology - Interim Support

The status of oxy-fuel technology for first-generation plant is indicate...

C18007Review Of Underground Coal Gasification

This report consists of a broad review of underground coal gasification,...

Low Emission Coal Use

Mining And The Community

The relationship between mines and the local community.

Recently Completed Projects

C16027Assessing Housing And Labour Market Impacts Of Mining Developments In Bowen Basin Communities

The focus of this ACARP-funded project has been to identify a number...

C22029Understanding And Managing Cumulative Impacts Of Coal Mining And Other Land Uses In Regions With Diversified Economies

The coal industry operates in the context of competing land-uses that sh...

C23016Approval And Planning Assessment Of Black Coal Mines In NSW And Qld: A Review Of Economic Assessment Techniques

This reports on issues surrounding economic assessment and analysis ...

Mining And The Community

NERDDC

National Energy Research,Development & Demonstration Council (NERDDC) reports - pre 1992.

Recently Completed Projects

1609-C1609Self Heating of Spoil Piles from Open Cut Coal Mines

Self Heating of Spoil Piles from Open Cut Coal Mines

1301-C1301Stress Control Methods for Optimised Development...

Stress Control Methods for Optimised Development and Extraction Operations

0033-C1356Commissioned Report: Australian Thermal Coals...

Commissioned Report: Australian Thermal Coals - An Industry Handbook

NERDDC