Technical Market Support

Nanoporosity in cokes: their origin, control and influence on CO2 reactivity

Technical Market Support » Metallurgical Coal

Published: June 20Project Number: C26039

Get ReportAuthor: Mihaela Grigore, Richard Sakurovs, Lukas Koval, Elizabeth Gawronski, Ian Campbell and Ali Kiani | CSIRO

This project using the outcomes of previous project C24060, examined how the total, closed and open porosity of cokes is affected by partial gasification of the coke and how this varies with pore size. Because maceral composition is believed to be important in predicting coke reactivity, we also investigated cokes made from maceral concentrates.

The coals used for coke preparation were bituminous coals from the Bowen Basin and the Illawarra Measures. Maceral concentrates were prepared from three Bowen Basin coals and one Illawarra Measures coal. The maceral concentrates along with the original coals were carbonised in a 70 g oven. A set of six coals of similar sources were carbonised in a pilot coking oven (300 kg). The cokes prepared in different ovens enabled us to investigate the influence of coking conditions on coke structure and its reactivity. The reactivity tests on the cokes were performed in a fixed-bed reactor under chemically controlled conditions, to different burn-outs 25%, 50% and 75%. Small Angle Neutron Scattering and Ultra Small Angle Neutron Scattering techniques were used for analysis of closed and open porosity in cokes and coals. Three cokes were annealed to 1400°C and 1600°C to determine how porosity changes at high temperature.

It was confirmed that nanoporosity in cokes is largely inherited from the coals. If there were no connections between nanoporosity of coals and nanoporosity of the product cokes, then predictions of coke reactivity from coal rank and maceral composition could never be improved, since there would be no fundamental connections between the organic part of the coal and coke properties, only empirical ones.

Using neutron scattering to characterise coke structure, some of the new findings were unprecedented and shed new light on what happens to coke after reaction with CO2. These include:

  • On gasification closed pores were opened and new pores were formed. The amount to which each occurred at a fixed burn-out level varied with rank, maceral and mineralogical composition of the original coal.
  • In three of the inertinite derived cokes nearly all of the pores - even those of 1nm size - became accessible at 25% burnout, but in vitrinite-derived cokes much of the remaining nanoporosity remained inaccessible even after extensive burn-out.
  • New pores were produced during burnout: this means that even on accessible surfaces, the reaction of coke with carbon dioxide does not occur at a uniform rate. In the cokes made from the two lower rank vitrinite-rich components, there appeared to be selective attack on open 20-80 nm sized pores.
  • Gasification increased dramatically the number of finer open pores (1-30 nm radius) in all cokes compared to those of larger pores (30-100 nm radius). Coal rank, maceral type and region appear to have no influence on this. However, catalytic minerals appear to promote the production of larger (40-100 nm radius) open porosity.
  • Annealing has a dramatic effect on coke structure from 1 nm to 2000 nm radius. It increases both closed and open porosity, and the effect increases with increasing temperature. The largest difference in coke porosity occurred at about 10 nm radius.
  • The effect of temperature on structure differs between cokes. Thus we would expect that NSC tests results of cokes after annealing at high temperature will be different to those of the unannealed cokes.

The results show that the nanostructure of cokes is modified during reaction with CO2 and also how the modification is affected by the maceral composition, rank and mineralogical composition of the original coal. By determining how coke nanostructure changes on reaction with CO2, it becomes feasible to better predict what happens to a coke when it reacts with CO2 and how fast the reaction happens.


Health and safety, productivity and environment initiatives.

Recently Completed Projects

C27052Site Trial And Demonstration Of Integrated Forward And Reverse Osmosis For Mine Water Reuse

The forward osmosis (FO) process, also known as direct osmosis, is a...

C28022Development Of A Simple Rotary Steerable System For Underground Inseam Drilling

The purpose of this project was to complete the design and testing o...

C21002Measurement And Reporting Of Fugitive Emissions From Underground Coal Mines

The National Greenhouse and Energy Reporting Act 2007 (Act), the ...


Open Cut

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

Recently Completed Projects

C28034Mining Equipment Human Factors Design For Workforce Diversity

The objectives of the project were to:

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

Recently Completed Projects

C27025Quantifying The Step-Change Benefit Of Reflux Flotation Cell Circuits

The objective of this project was to quantify the value proposition ...

C24047Characterisation Of Pressure (Hyperbaric) Filter Performance

Hyperbaric disc filter technology has been used to dewater fine coal...

C28058Phase Two Development Of A Low Cost Online Measurement Of Particle Size And Density For Diagnostics Across The Fine Coal Circuit (Particle Profiler)

This project is based around the development of a prototype system (...

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


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