Coal Preparation

A New Flowrate Measuring Technique for On-Line Monitoring of Coal Washing Processes (Stage 1) and Cross Correlation Flowmeter Plant Trial (Stage 2)

Coal Preparation » Process Control

Published: February 05Project Number: C10046

Get ReportAuthor: Michael O'Brien, Shenggen Hu, Ian Hutchinson | CSIRO Energy Technology

This project has developed and field tested a simple, robust flow rate measuring technique based on signal cross-correlation. It was conducted in two stages. The first, for which a report was published in October 2002, conducted a proof of concept investigation at pilot scale over a wide range of velocity, particle topsize, solids concentration, pipe diameter and pipe orientation. The experimental data showed that the cross correlation flow meter can provide precise (less than 10%) and accurate (5% of mag flow readings) measurements of slurry velocities for diverse feed types at solids concentrations as low as 0.3% w/w.

The second stage developed a robust prototype and carried out on-line testing of a DMC feed to determine the slurry velocity in an operating plant. New robust and environment protected circuits were designed and built. While the circuits built for stage 1 were similar in design they were not suitable for use in the plant environment. The new circuits were designed to give small robust boards which could be mounted in a VersaTainer® ruggedised enclosure. Considerable time and effort went into producing this part of the instrument to ensure a reliable operation in a plant environment. The tuning circuit, which is used to inductively tune the circuit to optimise the signal output from the demodulating circuit, was redesigned from scratch and built for the plant tests to give a high signal to noise ratio in a compact robust enclosure, separate from the generation and demodulation circuits in order to keep it as close to the electrodes as possible for optimum tuning. This new circuit was capable of reducing the system noise by a factor of 10 compared to the old tuning circuit used.

The instrument outputs two analog voltage signals which are collected via a National Instruments PCMCIA data acquisition card operating in a laptop. LabView® software was used to collect and process the signals, which were filtered, passed to a cross correlation function and the velocity determined based on the average time of flight as determined by the cross correlation function and the distance between the two electrodes.

A basalt lined pipe spool piece with a 300mm inside diameter was constructed with flanged ports through which the measurement sensor could be inserted. The measurement sensor consisted of four 316 stainless steel electrodes 0.9mm in diameter set 3mm apart and cast into a wear resistant epoxy to resist abrasion. This sensor was constructed from materials designed to last the duration of the project only. The sensor was inserted into the pipe spool piece until the face of the electrode was flush with the inside basalt pipe lining. Two of the electrode ?wires? were used to transmit the excitation signals and the other two used as measurement electrodes. Data was collected over two trips; the first trip involved testing the hardware and developing the software configuration which may best suit the site. On examining the FFT of the processed signals two close peaks not present in the pilot plant data were found at this plant. During the first trip in June these peaks were quite small compared to the signals generated by the cross correlation events, however during the August trip these peaks were large compared to the signal of interest and careful selection of band pass filters were needed to ensure that the signals did not interfere with the measured cross correlation signals found at the lower end of the frequency spectrum.

During the two months between trips the sensor was left in the pipeline to determine the effect of wear on the signal, examination of the wear resist tip showed some wear of the matrix material around the wear resist particles. The measured cross correlation signal strength was reduced by a factor of four however the signal was still sufficiently strong to produce credible results albeit with a slightly higher raw data standard deviation then the June results. It should be noted that this probe was a prototype and was designed to last the length of the test period only. Materials selection would considerable decrease the rate of wear on this probe particularly if the electrodes were embedded in a ceramic or basalt material.

Velocity data collected during the second trip was compared to calculated flow rates based on the feed pressure and cyclone nominal feed rate. No correlations were found in the data variations between the two measurements or in spikes or trends. These variations in the order of 5% to 10% of the flow velocity to the DMC was unexpected and has obvious implications to the operation of the DMC. The velocity measurements were taken at a point 4m below the cyclone inlet from where the pressure measurements were made. The pressure measurement therefore may be influenced by different factors which influence the cross correlation flow meter. Calculations of the medium to coal ratio at the same point in the DMC feed line using EIS technology(Hu and Firth 2005) found that the coal to medium ratio was also varying in a similar manner to the cross correlation velocity measurements indicating a potential solids surge effect. The cross correlation flow meter will measure particle events crossing the two electrodes while the pressure cell measures an average head or energy not related to the particles within the slurry. For this reason it is not unexpected that the pressure and cross correlation readings while measuring similar velocities would not necessarily have a high correlation with each other in terms of spikes and trends.

This reports shows that a direct, reliable and cost effective method for the measurement of pipe slurry velocity in coal preparation plants can be achieved. This method is applicable to a broad range of slurry types such as tailings, flotation feed and DMC feed. This system could easily be adapted to connect to the plant control system in either a hardwired format or wireless giving an analog signal proportional to the velocity in the pipeline. The method is not inferred from other properties but is a direct measurement of the transit time of resistivity fluctuations between two electrode pairs referenced to the computer clock, and as such is a primary calibration source.


Health and safety, productivity and environment initiatives.

Recently Completed Projects

C34019Longwall Bretby Cable Handling Monitoring With Fibre Optics

This project examined the potential of using fibre optic sensing tec...

C28028The Inclusion Of High Interest Native Plants In Mine Site Restoration Programs: Propagation, Translocation And Field Re-Introduction

This report synthesises over 10 years of ex situ and in si...

C27049Mine Machine Radar Sensor Integration

The aim of this project was to develop an integrated radar sensor an...


Open Cut

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

Recently Completed Projects

C34029Validation Of Laser Induced Breakdown Spectroscopy (LIBS) As A Rapidly Deployable Field Technology To Estimate Coal Quality

Rapid evaluation of a coal resource by in-situ characterisation dow...

C34028Guidelines For Assessment Of Geotechnically Safe And Stable Post-Mining Landforms

The purpose of this project was to develop a guidelines document as ...

C34016Elements In Coal – A Start-To-End Analysis

This project explores the fate and concentration potential of critical e...

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

Recently Completed Projects

C26016Determining The Benefits Of Online Thickener Underflow Rheology Measurements

The aim of this project is to determine how useful the rheology meas...

C33056Modelling And Control Of Classifying Cyclones

Hydrocyclones are one of the key technologies for the classification...

C28056Surface Alloying Of Centrifuge Baskets And Sieve Bends Screen Surfaces To Increase The Service Lifetime

The main objective of this project was to improve the wear resistanc...

Coal Preparation

Technical Market Support

Market acceptance and emphasising the advantages of Australian coals.

Recently Completed Projects

C33066Washability And Distribution Of Sulfur And Trace Elements For Different Size And Density Fractions Of Raw Coals

Based on the hypothesis that the levels of sulfur and other toxic tr...

C34060In-Situ Investigation Of Coke Structure Formation Under Stamp Charged Coking Conditions

Stamp charged cokemaking has emerged as an effective technique to im...

C34062Improving The Classification Of Microstructure Distribution In Coke CT Images Using Deep Learning And Lineal Path Calculations

This project builds on a number of earlier projects that have helped...

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)

This third and final stage of this project was the culmination of a ...

C29069Low-Cost Catalyst Materials For Effective VAM Catalytic Oxidation

Application of ventilation air methane (VAM) thermal oxidiser requir...

C23052Novel Stone Dust Looping Process For Ventilation Air Methane Abatement

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

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