ACARP ACARP ACARP ACARP
Coal Preparation

Improved Ultrasonic Flow Measurements of Coal Slurries

Coal Preparation » Process Control

Published: May 04Project Number: C11014

Get ReportAuthor: Stephen Sullivan, Andrew Meyers, Bob Leach, Michael O'Brien | A&B Mylec, CSIRO Energy Technology

The measurement of volume flows, using portable ultrasonic flow meters, has been a major tool used in the data collection phase during plant audits in the coal industry. The accuracy of these ultrasonic flow measurements have been inconsistent due to various influences, generally related to fluid turbulence and non-full pipe flows. Additionally, more recently, the proliferation of wear resistant lined pipes, eg: ceramic and basalt linings, has resulted in a significant decrease in the accuracy and reliability of these portable ultrasonic flow meters, usually reflected in reduced unit signal strengths.

This project investigated the principal causes of the decreased signal strength and any associated "Non-Doppler" frequency altering effects of the ultrasonic signal as it passes through the steel/lining/coal slurry medium. The project testing involved the measurement of Doppler-Effect flow signals under a range of piping mediums and flow conditions. The specific objective of the project was to investigate and optimise the variables involved with attaining reliable and accurate flow rate measurements.

Current technologies basically address the resolution of the "true" signal from the sampled signal and not signal attenuation issues, caused by the transmission path. The proposed approach in this project is to alter the emitted signal to enhance unit performance rather than waiting until signal capture and then to try and resolve the Doppler spectrum. The proposed technique seeks to improve the accuracy and precision of the resultant flow signal by enhancing the emitted signal instead of the captured waveform.

Key conclusions for the project:
  1. The difficulty in achieving an adequate Doppler-Effect flow meter signal on lined pipes is directly related to the attenuation of the transmitted signal resulting in an inability to discern its specific frequency spectrum from that of the background noise.
  2. Lined pipes may cause high signal attenuation in two (2) ways
    1. Bonding material degradation may cause an air gap to form in the wall cross section. (Resulting in a high attenuation solid/air interface).
    2. Material used to create the pipe wall may cause high attenuation due to its high sonic impedance.
  3. Due to the attenuation for a given transmission path remains constant with variation in emitter signal strength, an increase in the magnitude of the emitted signal (Voltage peak-to-peak) is believed to be the optimum mechanism to generate improved signal to noise ratios on lined pipes, or mediums of high sonic impedance.
  4. Basalt lined pipes gave the worst return signal frequency spectrums due to the low signal to Noise Ratio SNR. Both Poly and steel piping mediums displayed adequate SNR's, sufficient to determine viable flow readings.
  5. It is believed that as flow rate increases there is a larger differential between the laminar wall flow rate and that of the centre flow rate. Should the emitted signal from the flow measurement device fail to penetrate into the centre flow stream, then increasing errors in the observed flow rate are likely to result. This was reflected in a divergence of certain flow meter readings with increasing flow rate.
  6. Using an exposed lining technique and mounting the transducers directly to the lining material significantly improved the ability to achieve a reliable flow measurement.
  7. The impact on flow measurement accuracy on transducer position around the circumference of the pipe is critical. The mounting of the transducers on the pipe at 90 degrees was found to deliver the most reliable flow readings under the conditions tested. However, it is believed that 180 degrees should deliver the optimum measurement of average particle flow in the pipe due to the likelihood that return frequency spectrum would be generated from reflection from the full stream flow profile.
  8. The test unit with the greatest available transmitter voltage peak-to-peak consistently delivered the best flow rate measurements for all of the test run conditions and piping mediums when compared to a reference MagFlo meter.
Key outcomes from this project:
  1. Development of an exposed lining technique for measurement on lined pipes, in particular basalt lined pipes.
  2. The detailing of a proposed conceptual Doppler flow meter inclusive of a range of functionality believed to make such a device capable of generating viable flow measurements on basalt lined pipes and/or high sonic impedance piping mediums.

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