ACARP ACARP ACARP ACARP
Technical Market Support

Optimisation of the Gieseler Fluidity, Dilatation and Crucible Swelling Number of Australian Coking Coals

Technical Market Support » Metallurgical Coal

Published: June 00Project Number: C9061

Get ReportAuthor: Adrian Reifenstein, Charles Coin, Paul Sullivan | ACIRL

Crucible Swelling Number, Audibert-Arnu dilatometer and Gieseler plastometer residua were collected for a range of Australian coals. The samples were examined at the optical microscope and hand specimen level, to understand the processes that influenced the results. This was with an aim to understand the relationships between these indices and the results obtained from coal carbonisation and coke testing.

The high heating rate in the Crucible Swelling Number [CSN] test produced residua that was least like coke, both in morphology and molecular ordering. During the CSN test, the rate of volatile production within the individual particles exceeded the rate of diffusion through the particles resulting in the formation of numerous pores. As a result of pore formation and development the semi-plastic particles expanded until they compressed against the surrounding particles, forming pore wall material. Larger pores evolved by coalescence with surrounding pores and by further migration of volatile matter from the pore wall material. With increased molecular ordering of the pore wall material, a more dense pore wall microstructure developed. As the pore wall microporosity decreased, the remaining volatile matter did not easily diffuse through the forming coke matrix and a set of smaller pores formed in the pore wall material. The interconnection of the macropores and venting of the volatiles in the latter stages resulted in partial collapse of the foamy structure.

In the Audibert-Arnu Dilatometer test, between the initial softening temperature and the temperature of maximum contraction, softening of grain boundaries with the associated devolatilisation and loss of inter-particle pores resulted in volume loss. In the latter part of this stage intra-particle pore formation was initiated. At the temperature of maximum contraction, inter-particle space had been mostly eliminated and the mass loss due to the devolatilisation process was offset by the volume gain due to intra-particle pore formation. This resulted in a halt in the contraction rate. With a further increase in temperature, intra-particle porosity significantly exceeded mass loss due to devolatilisation and the pencil expanded. The cessation in dilatation was initially not due to resolidification of the pencil, as the temperature at which this occurs is generally lower than the resolidification temperature determined in the Gieseler dilatometer test. It is most probably a result of the force being applied to the piston by the expanding pencil being equal to the force due to the mass of the piston.

It was found that the Gieseler Plastometer results were influenced primarily by the expansion of the transforming coal/coke due to the formation of gasification pores. A strong relationship was found between the density of the residua and the maximum Gieseler plasticity, indicating that this test was not measuring the fluidity of the transforming material but rather the amount of material in the path of the stirrer arms. The residua also showed that the stirrer arms ploughed voids in the transforming material. These voids persisted for up to ? of a revolution behind each arm. For high plasticity samples, the adhesion of the transforming material to both the spindle and the wall of the retort produced a different shaped [spiral] residuum compared to the more dome-like structure of less plastic samples. It may be that the viscosity of the transforming material may be being measured in the Gieseler plastometer test. However, rather than at the point of maximum "Fluidity", it is being measured prior to the formation of gasification pores.

No significant relationships were found between the three tests examined and any of the coke quality indices including cold coke drum strength indices, CO2 reactivity indices, maximum coking wall force measurements or maximum internal gas pressures.

Underground

Health and safety, productivity and environment initiatives.

Underground

Open Cut

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

Recently Completed Projects

C19024Establishing Ecologically Sustainable Mine Water Release Criteria In Seasonally Flowing Streams

Extreme rainfall conditions in the Fitzroy Catchment over an approxi...

C25030Coal Mine Open Pit Final Void Closure And Relinquishment - Addressing Uncertainty In Coal Mine Environmental Planning

This report addresses uncertainties faced by coal mine operators whe...

C27046Estimation Of True Deformation Vector From Slope Radar Monitoring

Slope deformation radar monitors are now widely used in open cut coa...

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

Recently Completed Projects

C27004Improving Coal Flotation With Oscillatory Air Supply

This report provides detailed information on coal flotation with os...

C25018Improving Solids Recovery And Moisture Reduction In Ultrafine Coal Dewatering

This report provides detailed information on fine coal dewatering in...

C27028Lab Froth Flotation Testing Guide With Coal Quality

Correct outcomes from laboratory froth flotation testing in coal bor...

Coal Preparation

Technical Market Support

Market acceptance and emphasising the advantages of Australian coals.

Recently Completed Projects

C26039Nanoporosity In Cokes: Their Origin, Control And Influence On CO2 Reactivity

This project using the outcomes of previous project C24060, examine...

C28063A Comprehensive Technical Review Of High-Efficiency Low-Emission (HELE) Pulverised Coal Combustion Technologies For Power Generation

Research and development has been undertaken worldwide to realise co...

C28064Carbon Structure Transformation During Coking Of Australian Coking Coals: Better Understanding The Coke Formation

Carbon structures of coke that are formed during the plastic layer a...

Technical Market Support

Mine Site Greenhouse Gas Mitigation

Mitigating greenhouse gas emissions from the production of coal.

Recently Completed Projects

C28076Selective Absorption Of Methane By Ionic Liquids (SAMIL) - Phase 2 Demonstration In A Packed Bed Reactor

An alternative approach to high temperature oxidation of ventilation...

C26004CFD Modelling Of Reverse Thermal Oxidisers For VAM Abatement - CFD Modelling Of Fixed-Bed RTO Devices

The project is part of a larger multi‐phase program of study a...

C27058Technological Assessment Of A Recycle Reactor For VAM Abatement

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

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