ACARP ACARP ACARP ACARP
Coal Preparation

Reduced Cyclone Wear and Maintenance

Coal Preparation » General

Published: October 06Project Number: C13053

Get ReportAuthor: Anita Hill, James Mardel, T Markley, T Bastow, R Hannink | CSIRO Manufacturing and Materials Technology

This project gives details of a study of the wear and performance of DMCs from the Hunter Valley and the Bowen Basin.  The project consisted of information gathering, in-situ monitoring of DMCs, and ex-situ failure analysis of DMCs. 

Due to cost factors there is a limited number of wear materials used for DMCs, namely Ni-hard cast iron or alumina tiles. 

The service lifetime of DMCs is variable, with complete change out, due to wear, occurring at anytime from 12 months to more than 8 years.  Alumina lined DMCs have a lower wear rate and less change in internal dimensions than Ni-hard DMCs for the conditions examined here (Hunter Valley and Bowen Basin).  The longer lifetime and consistent wear translate to cost savings and efficiency, respectively.  However, there is a reluctance to use alumina due to its catastrophic failure mode and the inability to patch/repair.  Catastrophic failure due to tramp material dramatically reduces the lifetime, with the worst case reported at 3 days.

Three failure mechanisms were identified:

  • Catastrophic failure due to overload (Ni hard and alumina) 
  • Erosion-corrosion and cracking (Ni-hard cyclones)   
  • Abrasive wear (Ni-hard and alumina)

Catastrophic failure comprised less than 5% of the cases studied; however, catastrophic failure caused many tens of thousands of dollars of lost revenue production time.  It has been concluded that the conditions for catastrophic failure can be avoided.

Erosion-corrosion due to inclusions (large inhomogeneities in the material) was observed in greater than 50% of the Ni-hard DMCs indicating poor metallurgical control by the manufacturer.  Better control over the composition, the casting cooling rate, and the subsequent heat treatment are necessary for optimum wear life.

Improvements in DMC lifetime and performance can be made in several ways.

  • The DMC manufacturers can optimise the wear materials for the mineral impurity (ash) content of the coal.  The wear rates can be minimised by controlling the processing and composition of Ni-hard and alumina at the manufacturing end.  The alumina tile wear rates can also be minimised by reducing the angle between the tiles (smoothing the joint between tiles). 
  • Plant managers can specify the materials characteristics to the manufacturer (e.g. Ni hard cast iron with uniform fine dispersion of carbides less than 20mm grain size) instead of specifying just the material (e.g. Ni-hard).  In this way, the microstructure of the Ni-hard is matched with the ash size, reducing the wear rate and increasing the corrosion resistance.
  • Non-destructive evaluation techniques such as ultrasound or X-ray may be used to detect large inclusions in Ni-hard cyclones prior to installation.
  • Plant managers can screen to control the size of tramp entering the cyclone. 
  • Plant managers can monitor and control feed pressure at the inlet. 

A trend that was evident from our interviews was that cyclone performance and wear monitoring was not carried out as regularly as may be needed to ensure that optimum operating conditions of the DMC are maintained.  Another area of concern identified was the possible inaccuracies in measurement of feed inlet pressure into the DMC.  Pressure gauges are located up to 4m away from cyclone inlet, so actual inlet pressure could be higher than that measured.  This increase in pressure would translate to particles of higher velocity entering the cyclone body and increasing the amount of wear and changing the cut-off condition. 

For properly manufactured wear materials, the main cause of corrective or emergency maintenance downtime is due to tramp.  For the plant of the future, which will utilise predictive maintenance with one 12 hr maintenance period occurring every three months, both Ni-hard and alumina wear materials are adequate if the materials are properly manufactured and the operating conditions are controlled.  If one assumes that a 20% change in internal dimensions causes an unacceptable loss of material to discard [ACARP C10045], then properly manufactured alumina DMCs will perform at least 5 times longer than properly manufactured Ni-hard DMCs.  A purchasing decision based on whole of life costing can then be made by the plant manager.

It is recommended that:

  1. DMC manufacturers be approached to discuss the optimisation of existing wear materials, both alumina and Ni-hard
  2. DMC manufacturers include microstructure information, wear rates by standard test method, and fracture toughness of the wear materials in their specifications
  3. Non-destructive evaluation methods for the detection of inclusions be developed in collaboration with the manufacturers such that the manufacturers can use the method for quality control
  4. Methods to eliminate or at least control the size of tramp be investigated and implemented
  5. New composite wear materials that may extend wear life whilst eliminating the catastrophic failure mechanism be investigated.

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