Mine Site Greenhouse Gas Mitigation

The Optimisation and Application of Hybrid Chequer Bricks in Regenerative Thermal Oxidisers for VAM Abatement

Mine Site Greenhouse Gas Mitigation » Mine Site Greenhouse Gas Mitigation

Published: July 20Project Number: C28075

Get ReportAuthor: Mohammed Al Zuraiji, Jafar Zanganeh, Behdad Moghtaderi | University of Newcastle

The capture and use of ventilation air methane (VAM) is regarded as one the most effective means of mitigating fugitive methane emissions in underground coal mines. Methane is the most potent of the greenhouse gases which is emitted during the production and transportation of coal, natural gas and oil. A particular problem is fugitive emissions of methane from the ventilation systems of underground coal mines. In recent years, regenerative thermal oxidiser (RTO) and catalytic thermal oxidiser (CTO) technologies have been adopted to reduce the VAM emissions from underground coal mines. In these technologies, the fixed-bed mediums (i.e., chequer bricks) are considered to be the primary layer of protection to arrest any potential flames travelling from the abatement devices into the coal mine. Despite the important role that these chequer bricks play, from a safety point of view their performances, particularly against flashbacks from the RTO/CTOs into the mine, should be investigated and verified further.

The principal vision of this project was to develop methods for the optimisation and enhancement of the flame arresting properties of the chequer bricks. To fulfil this vision, the project aimed to develop a number of hybrid chequer brick configurations which combined several brick designs in order to examine the behaviours of the hybrid configurations under fire and explosion scenarios pertinent to RTO/CTO based VAM abatement systems. This small-scale pilot study examined the properties, configurations and flame mitigation performances of the newly designed chequer brick flame arresters.

To gain fundamental insights into the flame arrester chequer bricks developed for potential future use in RTOs and CTOs, the project undertook:

  • An examination of the mechanical and thermophysical properties of chequer bricks.
  • The design and manufacture of the most suitable and practical configurations of the hybrid brick flame arresters for testing, assessment and potential future use. These were achieved through comprehensive desktop and laboratory studies.
  • An assessment of the flame mitigation performances of a number of different configurations of the small-scale brick flame arresters were undertaken in methane flame propagation conditions. The testing was carried out in a small-scale propagation tube which was 5 m long and 75 mm in diameter.
  • The optimisation of the small-scale bricks and then the manufacture of different configurations of the large-scale flame arrester chequer bricks. The mitigation performance testing of the large-scale brick flame arresters was conducted in a pilot-scale detonation tube.


The key findings of the project:


Flame Arresting Performances of the Chequer-Bricks

The experimental assessment of the flame arresting properties of the chequer bricks indicated that there were some mixed and inconclusive results. The small-scale and large-scale brick flame arresters demonstrated successful flame mitigation performances, however while under the same conditions and for the same scenarios they failed to stop and mitigate the flames caused by different methane concentrations (e.g., 6.5%, 8%, 9.5% and 12.5%). Amongst the three different configurations of the small-scale brick flame arresters (i.e., Configurations A, B and C), the Configuration C flame arrester demonstrated a relatively better mitigation performance in comparison to the other configurations. All three configurations of the brick flame arresters demonstrated better flame mitigation performances for the stoichiometric methane concentrations. The failure rates of the arresters were less for the stoichiometric methane concentrations in comparison to the leaner and richer methane concentrations. This was mainly due to the stronger flame propagation pushback created by the reflected pressure wave for these concentrations. The pressure wave was reflected when the flame propagation wave hit the flame arrester and bounced back.


Impacts of the Size of the Flame Arrester (Length to Diameter (L/D) Ratio) on the Flame Mitigation

It was determined that the length to diameter (L/D) ratio had a significant impact on the flame mitigation performances of the brick flame arresters. Overall, the chequer bricks with larger L/D ratios demonstrated better flame mitigation performances. The experimental study for both the small-scale and large-scale brick configurations was carried out for L/D ratios of up to 8. It was found that for the small-scale flame arresters with an L/D ratio < 4, the flame could penetrate through the brick flame arresters and then accelerate in the form of a jet fire. It was identified that the frequency of the failures of the bricks was significantly reduced as the L/D ratio increased, however none of the L/D ratios could completely stop the propagation of the flames.

Material Selection and Fabrication

Although different fabrication methods for the brick flame arresters were tried at an early stage of the project, it was identified that the water jet cutting approach was the most reliable and precise method of producing the chequer bricks in any shape and configuration, and from different materials.

Impact of the Stabilised Combustion on the Failure of the Flame Arrester Bricks

A stabilised combustion refers to combustion on the upstream side of the flame arrester. In this study, it was found that a period of stabilised combustion seemed to have a large impact on the failure rate of the flame arrester. The impacts of the stabilised combustion on the flame arresters were more pronounced for those with an L/D ratio > 4. The duration of the period of stabilised combustion for the small-scale brick flame arresters was up to about 280 ms.

Dynamic Pressure Reductions Across the Brick Flame Arresters

The application of brick flame arresters was shown significantly increase reductions in the dynamic pressure. It was found that the pressure drops increased as the L/D ratio increased. The highest dynamic pressure reduction range was about 97%, which was for the Configuration C flame arrester with an L/D ratio of 8.


Influence of Coal Dust on the Failure of the Flame Arresters

It has been identified that fine coal dust particles enhance the severity of methane explosions. The assessment of the experimental performances of the large-scale brick flame arresters indicated that the application of coal dust particles mixed with the methane significantly increased their failure rate in stopping the propagation of flames.


Health and safety, productivity and environment initiatives.

Recently Completed Projects

C27039True Triaxial Strength Of Coal Measure Rocks And Its Impact On Roadway Stability And Coal Burst Assessment

Rocks in the ground are subject to a range of stresses. The stresses...

C3063Underground Vehicle Design Standards And Statutory Implications

The Australian underground diesel vehicle fleet has evolved since di...

C3064Conveyor Belting And Lagging Shear Characteristics - Drive Drum Slip

The primary aim of this project was to investigate the relationsh...


Open Cut

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

Recently Completed Projects

C26029Geological Controls On Fluorine And Phosphorus In Bowen Basin Coals

Increasing global restrictions on fluorine in product coal prompted ...

C28033Raw Ash To Yield Relationships

Correct outcomes in yield predictions for product ash from coal bore...

C27038Establishing Self-Sustaining And Recognisable Ecological Mine Rehabilitation

In recent years an increasing interest has been placed on mining ope...

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

Recently Completed Projects

C27064Dry Beneficiation Using FGX And X-Ray Sorters

Conventional dry processing methods engage a single beneficiation de...

C26010Multi-Sloped Screening Efficiency With Changing Strokes, Frequencies, Feed Solids And Feed Rates-Pilot Plant Study

Optimising multi-sloped screens is often described as an art and the...

C28059Impact Of Water Quality In Coal Handling And Preparations Plants

The objective of this project was to deliver a concise reference do...

Coal Preparation

Technical Market Support

Market acceptance and emphasising the advantages of Australian coals.

Technical Market Support

Mine Site Greenhouse Gas Mitigation

Mitigating greenhouse gas emissions from the production of coal.

Recently Completed Projects

C23052Novel Stone Dust Looping Process For Ventilation Air Methane Abatement

This multi‐phase project is concerned with the mitigation of m...

C27054Optimisation Of A Thermal Flow Reversal Reactor For Ventilation Air Methane Mitigation

Ventilation air methane (VAM) generally accounts for 50-85% of the t...

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...

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


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