ICWES15 - Accelerated Drainage in Sand Piles by Convoluted Perforated Pipe. Presented by Eliza Hashemi, Melbourne, AUST

Accelerated Drainage in Sand piles by Convoluted Accelerated Drainage in Sand piles by Convoluted Perforated PipePerforated Pipe

Eliza HashemiEliza Hashemi

Dr. Muhammed BhuiyanDr. Muhammed Bhuiyan

Dr. Niranjali JayasuriyaDr. Niranjali Jayasuriya

Overview Overview

• Background Background

• Available OptionsAvailable Options

• Experimental ProcedureExperimental Procedure

• ResultsResults

• ConclusionsConclusions

BACKGROUNDBACKGROUND


The research is based on the problem presented to RMIT by Bacchus Marsh Boral The research is based on the problem presented to RMIT by Bacchus Marsh Boral Quarry for reducing drying time of sand stockpiles in the processing plantQuarry for reducing drying time of sand stockpiles in the processing plant

Boral Bacchus Marsh QuarryBoral Bacchus Marsh Quarry


• In the processing plant, sand is mixed with In the processing plant, sand is mixed with water and the clay/silt is removed.water and the clay/silt is removed.

• The washed sand (with 20% water) The washed sand (with 20% water) transferred to the plant to dry and reach the transferred to the plant to dry and reach the saleable moisture of 5-6%. saleable moisture of 5-6%.

• A moisture probe had been placed at 2m A moisture probe had been placed at 2m height inside one of the piles and recorded height inside one of the piles and recorded the drying trend. the drying trend.

• Result shows that the moisture reach from 21% to 5% in about 8 daysResult shows that the moisture reach from 21% to 5% in about 8 days• The moisture drops from about 21% to 9% within few hours; then the The moisture drops from about 21% to 9% within few hours; then the

drainage rate decreases as the excess water has drained out.drainage rate decreases as the excess water has drained out.• Space limit and delays in production process are the problems quarries are Space limit and delays in production process are the problems quarries are

facing these days. facing these days.


AVAILABLE OPTIONSAVAILABLE OPTIONS

Different methods proposed for the problem. Different methods proposed for the problem. After several literature review two methods were After several literature review two methods were chosen:chosen:

Spiral DrainSpiral DrainThe system was supposed to drain the excess The system was supposed to drain the excess water that remains at the piles base.water that remains at the piles base.

SurfactantsSurfactantsThe effectiveness of surfactants as dewatering The effectiveness of surfactants as dewatering agents in sand piles by reduction of surface agents in sand piles by reduction of surface tension of water adsorbed to the sand particles.tension of water adsorbed to the sand particles.

EXPERIMENTAL PROCEDUREEXPERIMENTAL PROCEDURE

A. Free Drainage


• The sand was mixed with water and placed on to the metal box in a way to shape a pile with 600 mm height and 700 mm diameter at the base.

• The probes were buried inside the pile.• The first probe was placed at 150mm

from the bottom and the second one at 350mm.

• The probes were connected to a data logger that read and recorded the moisture of the sand for several days.

Probe 2

Probe 1

A. Free DrainageA. Free Drainage

• The sand is in the box and in the lab condition for 14 days. On day 14 the moisture is about 14%.

• Probe 1 showed a slow drainage process due to the water gathered at the base.

Monitoring of moisture content with Probe 1


• The rapid drainage during the first few hours is more clear with Probe 2 which is placed above the Probe 1.

• On day 14 the moisture decreases to 8%.

A. Free DrainageA. Free Drainage

Monitoring of moisture content with Probe 2Monitoring of moisture content with Probe 2


The moisture probes results from free drainage step.

The reduction trend on the second probe seems quite faster.

Date Time Probe 1 Probe 2

01/02/2011 17:50:00 24.45693 21.05778

01/02/2011 17:56:00 24.46183 20.86109

01/02/2011 18:01:00 24.46183 19.5541

01/02/2011 18:10:00 24.46183 18.31694

01/02/2011 18:20:00 24.4289 17.54698

01/02/2011 18:33:00 24.41421 16.96707

01/02/2011 19:57:00 24.26558 15.92174

01/02/2011 20:32:00 24.21619 15.77146

02/02/2011 03:01:00 23.8237 14.98691

03/02/2011 09:17:00 22.62175 13.63572

04/02/2011 12:30:00 21.76913 12.71282

06/02/2011 05:39:00 20.30642 11.52561

06/02/2011 19:32:00 19.51832 10.91477

09/02/2011 02:48:00 17.3574 9.667

10/02/2011 02:43:00 16.76244 9.401358

13/02/2011 00:46:00 15.00647 8.61946

13/02/2011 05:28:00 14.87475 8.558022

15/02/2011 04:14:00 13.89975 8.231826

15/02/2011 13:10:00 13.7885 8.181438

B. Spiral Drain


B. Spiral DrainB. Spiral Drain

• A perforated pipe was fixed on a wooden A perforated pipe was fixed on a wooden board in circular shape and placed at the board in circular shape and placed at the bottom of the boxbottom of the box.

• The perforated pipe was attached to a The perforated pipe was attached to a suction pump with a connecting pipe. suction pump with a connecting pipe.

• The sand was placed over the perforated The sand was placed over the perforated pipe and probes were situated in the same pipe and probes were situated in the same places.places. The pump will suck excess water The pump will suck excess water from the pile base.from the pile base.

Experimental setup

Probe 2Probe 2

Probe 1Probe 1


Probe 1: the moisture content of the sample decreased to 10% in just one day and after 3 days to about 8%. The result showed some fluctuations due to discontinued pump operation.

RESULTS RESULTS


RESULTS RESULTS

The moisture content reduction at the point of Probe 2 is fast and obvious for the first few hours with pump working.

Probe 2: the moisture content decreased to about 4% after 3 days.


The moisture probes results with suction pump in progress.

Date Time Probe 1 Probe 2

17/02/2011 13:34:00 24.5 24.4

17/02/2011 13:36:00 25.0 24.5

17/02/2011 13:40:00 26.1 31.5

17/02/2011 13:42:00 25.4 28.4

17/02/2011 13:44:00 24.6 25.7

17/02/2011 13:48:00 23.1 22.1

17/02/2011 13:50:00 22.7 21.0

17/02/2011 13:59:00 20.8 17.6

17/02/2011 14:05:00 19.8 17.4

17/02/2011 14:11:00 18.7 16.3

17/02/2011 14:15:00 17.7 15.7

17/02/2011 14:38:29 16.1 13.4

17/02/2011 14:40:45 15.4 13.3

17/02/2011 14:43:23 14.8 13.2

17/02/2011 14:50:50 13.9 12.6

17/02/2011 21:59:00 9.6 6.9

18/02/2011 15:30:00 8.6 5.1

18/02/2011 18:15:00 8.4 5.0

19/02/2011 01:30:00 8.4 4.6

19/02/2011 23:55:00 7.9 4.0

RESULTS RESULTS

The suction capacity of the pump was 50 kPa at the start of the experiment and it decreased with moisture reduction in progress. On the 3rd day no water was drained through the pipe and the pump got air and the suction capacity decreased to less than 20 kPa.

Pump suction capacity

• By using the suction system, the moisture reaches to 4-8% in just 3 days while with no suction system it took more than 2 weeks. This is a preliminary study and more investigation is needed in the future.

• The drainage system worked effectively on the sample sand pile and drainage process happened in one fifth of the normal duration of time.

• The drying trend in the plant is quit different and is under the influence of weather conditions.

CONCLUSIONSCONCLUSIONS

Thank youThank you

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ICWES15 - Accelerated Drainage in Sand Piles by Convoluted Perforated Pipe. Presented by Eliza Hashemi, Melbourne, AUST