ACARP ACARP ACARP ACARP
Technical Market Support

Coal Fluidity, Stockpiling and Coke Quality

Technical Market Support » Metallurgical Coal

Published: May 03Project Number: C10055

Get ReportAuthor: Jeff Keating, Merrick Mahoney, Richard Sakurovs | BHP Billiton, CSIRO Energy Technology

One perception in the marketplace is that coking coal quality decreases during transport and stockpiling due to ageing. This ageing is often estimated using plasticity measures with the assumption that plasticity is an indicator of coal oxidation and, therefore, an indicator of potential adverse effect on coke quality. The project addressed the question of "What is the most appropriate measure of coal plasticity to assess change in coke quality?". Specifically a high volatile Australian coal was allowed to naturally age (oxidise). Various coal plasticity measures were evaluated along with the resultant coke quality. In addition, the interaction of the aged coal with fresh coal was studied.

The coal was aged within 200L drums inside an enclosed building. The ageing technique used was designed to be repeatable and should not be considered to be identical to stockpile ageing. The ageing time of samples stored in drums may not be the same as for coal stored in a stockpile. Both traditional and non-standard tests were conducted as the coal was aged. Traditional plasticity measures used included Gieseler plastometry, Ruhr Dilatation and Crucible Swelling Number (CSN, also called Free Swelling Index - FSI). The two non standard techniques used were - Proton Magnetic Resonance Thermal Analysis (PMRTA) and fluorescence. Each coke sample, produced in a 300kg pilot scale coke oven, was characterised by coke mean size, ASTM Stability and Hardness, JIS indices, Micum/Irsid indices and CSR/CRI.

Plasticity of the aged coal, as determined by Gieseler plastometry and Ruhr dilatation showed a significant, rapid decrease in plasticity with ageing. PMRTA showed a steady decrease in Fmax over the period of the study. Plasticity of the blend decreased, to a lesser degree, during the study. Results indicated that adding aged coking coals to fresh coal blends affected the plasticity of the blend only to the extent that the plasticity of the aged coal was affected.

Cold coke quality indices did not change significantly throughout the program for either the coke produced from the aged coal (aged coke) or the blend coal (blend coke), despite a significant change in the plasticity of the aged coal. As such, it was concluded that no relationship existed between coal plasticity and cold strength indices for the coals during the period of the study.

There was, however, a significant change in hot strength of the aged coke, measured by the NSC CSR/CRI test, during the study. The CSR/CRI was constant for the first 51 days of the program, even though the traditional plasticity measures showed a significant change, before decreasing. The best relationship between coal plasticity and hot coke strength was a linear relationship between the PMRTA Fmax and CSR/CRI indices. The change in blend coke CSR/CRI was less than the change in aged coke CSR/CRI. The aged coal was used in the blend at a level of 30%

It was concluded that changes in traditional plasticity measures could not be used to reliably predict changes in resultant coke quality for either the individual coal or blend. There was no significant change in cold coke strength for coke produced from either the aged or blended coals, despite significant changes in plasticity measures. One non-standard plasticity measure (PMRTA) showed a relationship to the change in hot coke strength for the aged coke. Results were less conclusive for the blend. It was unclear why PMRTA Fmax followed the change in hot coke strength better than the traditional plasticity measures. This is an area that could be explored further. The effect of the aged coal in a blend appeared to be a proportional effect.

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