ACARP ACARP ACARP ACARP
Low Emission Coal Use

Tarong Power Station - Unit 3 Boiler Combustion Optimisation

Low Emission Coal Use » Low Emission Coal Use

Published: March 09Project Number: C17059

Get ReportAuthor: Rob Korbee, Matt Barlow, Lionel Marshall, Elizabeth Hodge, Alicia Constable, Scott Salter | HRL Technology Pty Ltd

Optimisation of fuel and air distribution in a black coal fired utility boiler is one way to reduce the consumption of fossil fuel and abate CO2 emissions.

HRL Technology (HRLT), six Australian Generators and the Australian Coal Association Research Program (ACARP) funded a substantial research program to demonstrate the technical feasibility of real time coal flow distribution measurement, and the benefits of coal flow balancing.

Extensive trials were performed at Tarong Energy Power Station to provide the data needed to quantify the potential benefits of fuel distribution optimisation. To reduce cost, Unit 3 Boiler was selected for the trials as it already had installed valves to control coal flow in its fuel lines.

A relatively new, microwave-technology based, non-intrusive system was selected and acquired by HRLT to measure relative coal flows. The coal flow distribution was balanced by means of the existing adjustable valves in each pulverised fuel pipe. The combustion process itself was optimised using CFD (Computational Fluid Dynamic) model predictions. The differences between pre- and post-optimisation were measured by comprehensive testing.

The current project has established that coal mass flow distribution can be optimised using on-line microwave-based technology to measure the relative distribution of coal between burners in a row or group. A system purchased from MIC GmbH Germany was validated at two different power stations and provided results which were within a maximum 6% difference to traditional standard pulverised fuel sampling techniques. The MIC system was used to influence the coal flow distribution to a pre-determined non-ideal condition using existing, manually operated valves in the pulverised fuel lines. Comprehensive boiler tests were completed under this condition and then repeated after balancing the coal flows. Comparison of the test results before and after optimisation demonstrated the following benefits for a single 350 MWe unit:

- Boiler efficiency improved by 0.2% or fuel consumption reduced by 2,500 tonne coal per annum

- CO2 emission reduced by 6,000 tonne per annum

- Excess air trimmed back from 22% (3.5-4.0 %vol O2) to 8% (1.5 %vol O2)

- NOx emission reduced by 10% (and even by 30% after trimming excess air)

- Auxiliary power consumption reduced by 2,500 MWh per annum

The boiler efficiency improvement achieved was only modest; it is directly associated with an incremental improvement of fuel burnout which is traditionally high (99.4% fuel conversion, or a carbon in ash value of 1.3%) at Tarong Power Station. Computational Fluid Dynamic modelling has shown that, theoretically, another incremental improvement of 0.2% would have been obtained if the coal flow distribution were optimised more accurately. More significant efficiency improvements can be expected for power stations operating at higher unburnt levels. In addition, it was found that excess air requirements could be reduced quite drastically once the coal flows were balanced. In this case, while typically operating at 22% excess air (3.5-4.0 %vol dry basis of oxygen in flue gas), after balancing the unit could be run without problems at 7-8% excess air (1.5 %vol dry basis of oxygen in flue gas). An optimum excess air level can be found by negotiation between boiler efficiency and carbon in ash levels, and is essentially a result of the economic benefits that can be gained from both.

Capitalisation of the benefits of coal flow optimisation demonstrated in this study indicates that the combined dollar value is of the order of $1.5-3 million per GWe installed capacity per annum. Reduced CO2 emissions, maintenance (extended life of materials) and fuel savings are the main benefits obtained. Based on an budget cost for purchasing and installing a manually operated system on a 350 MWe boiler, a 1-2 year Payback Period and an Internal Rate of Return of 41-90% is expected. It should be noted, however, that the results obtained, and benefits concluded, are specific to the conditions of Tarong Power Station and need to be reviewed for other cases.

While the technique of real time coal flow measurement, and the benefits of its use in coal flow balancing, have been clearly demonstrated, it is recommended to extend this to include real time control of coal flow distribution. This would further pave the way towards combining fuel control and combustion performance monitoring systems to optimise combustion real time.

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