AU2021461615B2 - A pigging system and method - Google Patents

Abstract

A pipeline pigging system including: a pipeline used for material transportation, wherein the pipeline includes a rubber lining; at least one pigging device, arranged to be introduced into the pipeline at a first end of the pipeline, and caused to travel in the pipeline for pigging purpose between the first end and a second end of the pipeline; a launching system, for introducing the at least one pigging device into the pipeline at the first end, and a receiving system for collecting the pigging device at the second end of the pipeline after decaling.

Description

A pigging system and method

TECHNICAL FIELD

[001] TheThe present present disclosure disclosure relates relates to to systems systems andand methods methods forfor pigging pigging a pipeline. a pipeline.

BACKGROUND

[002] Pipeline transportation is a transportation method developed in the 1950's and has been widely

employed in metal mines, coal mines and non-metallic mineral mines. Compared with other types of

transportation methods, for example, automobile and train transportation, pipeline transportation has a

number of advantages, such as continuous operation, increased transportation capacity, reduced

environmental impact, low material loss, resistance to weather and climate conditions, low infrastructure

investment, low operating cost, and so on. In addition, long-distance pipeline transportation is highly

adaptable to changing terrains, and it is easier to transport materials across, for example, mountains and

rivers. It is one of the most practical and economical transportation methods, and has been widely used

especially with the increasing concerns over environmental protection.

[003] In mining operations, pipelines are widely used to transport slurry mixtures. In the initial stage of

slurry transportation, pipelines manufactured from a single metal material, such as unlined steel or

stainless steel pipelines, are generally utilised. However, these unlined steel pipelines have poor

corrosion and wear resistance and tend to scale, that is, a solid or semi-solid deposit will form on an inner

wall of the pipelines. The thickness of the deposit grows overtime, which can noticeably reduce the

transport capacity of the pipelines. The mineral processing industry soon proposed higher standards for a

pipeline's performance, such as wear resistance, corrosion resistance, and anti-scaling. Therefore, the

pipelines used for transporting slurry mixtures evolved from being manufactured from a single metal

material to other forms, including pipelines manufactured from multiple materials, pipelines with wear-

resistant rubber or ceramics lining, UHMWPE (ultra high molecular weight polyethylene) plastic pipelines,

and polyolefin composite wear-resistant pipelines in more recent years.

[004] Rubber-lined pipelines have been widely used in slurry transfer due to their improved

performance in corrosion resistance and wear resistance. However, slurry pipelines with a wear-resistant

rubber-liner, used for transferring slurry which contains calcium, magnesium and carbonate species,

reagents, ultrafine particles, or fibrous materials, are also prone to build up of scale residue. As soon as

scaling occurs on an inner surface of the pipelines, the thickness of the scaling will grow rapidly, which

leads to a decrease of the flow rate of the slurry in the pipelines. In a beneficiation plant, tailing slurry

transfer is essential to maintain continuous operation of production. The decrease of transfer capacity of

the tailing pipeline will become the bottleneck for the whole processing plant. In the past, acidic

chemicals, such as sulphuric acid and hydrochloric acid, have been used to remove the build up of

calcium carbonate and magnesium hydrate. It is known that chemical cleaning methods can potentially corrode pipelines and are found to be ineffective for some residues such as fibrous material scaling.

Chemical cleaning methods are also known to produce hazardous waste which is an environmental

concern.

[005] Accordingly, Accordingly, there there is is a need a need forfor a system a system and/or and/or a method a method of of pigging pigging a pipeline a pipeline which which ameliorates ameliorates

or addresses at least one of the issues mentioned above.

[006] Any reference to or discussion of any document, act or item of knowledge in this specification is

included solely for the purpose of providing a context for the present invention. It is not suggested or

represented that any of these matters or any combination thereof formed at the priority date part of the

common general knowledge, or was known to be relevant to an attempt to solve any problem with which

this specification is concerned.

SUMMARY OF THE INVENTION

[007] In In

[007] a first a first aspect, aspect, thethe present present disclosure disclosure provides provides a pipeline a pipeline pigging pigging system system including: including:

a pipeline used for material transportation, wherein the pipeline includes a rubber lining;

at least one pigging device, arranged to be introduced into the pipeline at a first end of the

pipeline, and caused to travel in the pipeline for cleaning purpose between the first end and a second end

of the pipeline;

a launching launchingsystem, system, for for introducing introducing the atthe at one least least one device pigging pigging device into into the the pipeline pipeline at the first at the first

end, end, and and a receiving system for collecting the pigging device at the second end of the pipeline after

decaling.

[008] In In an an embodiment, embodiment, thethe pigging pigging device device includes includes a substantially a substantially cylindrical cylindrical main main body body portion. portion.

[009] In In an an embodiment, embodiment, a diameter a diameter of of thethe pigging pigging device device is is smaller smaller than than an an inner inner diameter diameter of of thethe

pipeline.

[010] In an embodiment, the pigging device further includes a head portion formed in a truncated cone

shape, and extends from one end of the cylindrical main body.

[011] In an embodiment, the pigging device is made from compressible materials, allowing dimensions

of the pigging device to be varied to accommodate for different inner dimensions of the pipeline as it

travels between the first and second end of the pipeline.

[012] In In an an embodiment, embodiment, thethe compressible compressible materials materials have have a compression a compression rate rate of of about about 30%, 30%, that that is,is, thethe

diameter of the pigging device is able to be reduced by about 30% when it is compressed.

[013] In In an an embodiment, embodiment, thethe pigging pigging device device is is made made of of high high density density open open cell cell polyurethane. polyurethane.

[014] In an embodiment, the pigging device includes a polyurethane outer coating, wherein the outer

coating comprises surface formations that assist in lifting or removing the scales as the pigging device

travels within the pipeline.

[015] In In an an embodiment, embodiment, thethe polyurethane polyurethane outer outer coating coating is is attached attached andand wrapped wrapped around around at at least least a a

substantial outer surface of the pigging device.

[016] In In an an embodiment, embodiment, thethe surface surface formations formations include include raised raised structures structures which which areare evenly evenly distributed distributed

around the outer surface of the pigging device.

[017] In In an an embodiment, embodiment, thethe surface surface formations formations areare arranged arranged in in an an array array andand in in a crisscross a crisscross pattern. pattern.

[018] In In an an embodiment, embodiment, thethe polyurethane polyurethane outer outer coating coating is is of of a thickness a thickness of of 2 to 2 to 5 mm. 5 mm.

[019] In In an an embodiment, embodiment, thethe pigging pigging device device further further includes includes oneone or or more more gripping gripping portions portions arranged arranged to to

assist with moving or carrying of the pigging device by an operator or by a machinery when required.

[020] In an embodiment, the one or more gripping portions include one or more ropes.

[021] In In an an embodiment, embodiment, thethe oneone or or more more gripping gripping portions portions areare located located near near a front a front endend of of thethe pigging pigging

device and/or at a back end of the pigging device.

[022] In an embodiment, the one or more gripping portions additionally include a recess, or a channel,

formed at, or near the back end and/or a front end of the pigging device, allowing the pigging device to be

lifted by engaging the recess or the channel.

[023] In In an an embodiment, embodiment, thethe pigging pigging device device includes includes oneone or or more more bores bores which which extend extend in in a lengthwise a lengthwise

direction of the pigging device, allowing a material to move from a front end of the pigging device to a

back end of the pigging device and be discharged therefrom as the pigging device moves within the

pipeline.

[024] In an embodiment, the material includes water, or build up of materials removed from an inner

surface of the pipeline.

[025] In an embodiment, the pigging device includes a location tracking device, enabling positions of

the pigging device to be detected and forwarded to an electronic position receiver.

[026] In In an an embodiment, embodiment, a plurality a plurality of of pigging pigging devices devices which which areare of of different different diameters diameters and/or and/or surface surface

formations and are arranged to be introduced into the pipeline in a predetermined sequence.

[027] In In an an embodiment, embodiment, thethe plurality plurality of of pigging pigging devices devices include include four four pigging pigging devices: devices: a first a first pigging pigging

device device with with aa first first diameter diameter d1, d1, aa second second pigging pigging device device with with diameter diameter d1, d1, aa third third pigging pigging device device with with aa

diameter d2, and a fourth pigging device with diameter d2, wherein d1<d2, and wherein each of the

second, third, and fourth pigging device is provided with a polyurethane outer coating with surface

formations.

[028] In In an an embodiment, embodiment, thethe first first pigging pigging device device is is used used in in a pigging a pigging operation operation first, first, then then followed followed by by thethe

second pigging device, the third pigging device, and finally the fourth pigging device.

[029] In In an an embodiment, embodiment, thethe launching launching system system is is hydraulically hydraulically powered. powered.

[030] In In an an embodiment, embodiment, thethe launching launching system system includes includes an an inlet, inlet, into into which which thethe pigging pigging device device is is

inserted, an outlet coupled to the first end of the pipeline to be cleaned, and a launching pipe extending

between the inlet and the outlet of the launching system.

[031] In In an an embodiment, embodiment, thethe launching launching pipe pipe includes includes sections sections which which areare of of different different diameters. diameters.

[032] In In an an embodiment, embodiment, a diameter a diameter of of thethe launching launching pipe pipe at at or or near near thethe inlet inlet is is greater greater than than a diameter a diameter

of the launching pipe at or near the outlet.

[033] In In an an embodiment, embodiment, thethe launching launching system system further further includes includes a pressure a pressure balancing balancing pipe, pipe, which which

balances pressure changes between sections of the launching pipe which are of different diameters.

[034] In In an an embodiment, embodiment, thethe launching launching system system further further includes: includes: a fast a fast opening opening blind blind valve, valve, a pigging a pigging

device passing indicator, a pressure indicator, an air bleed and an air vent, and a drain valve.

[035] In In an an embodiment, embodiment, thethe pressure pressure indicator indicator is is used used to to monitor monitor a pressure a pressure inside inside thethe launching launching

system to avoid causing personal injuries when the fast opening blind valve is opened.

[036] In an embodiment, the air bleed and air vent are arranged to release air inside the launching

system.

[037] In an embodiment, the receiving system includes: an inlet, being coupled to the second end of

the pipeline to be descaled, an outlet, from where the pigging device exits and is collected, a receiving

pipe extending between the inlet and outlet of the receiving system.

[038] In an embodiment, the receiving system further includes: a fast-opening blind valve, a pigging

device passing indicator arranged to track the location of the pigging device within the receiving system,

pressure indicators, an air bleed and an air vent arranged to release the air inside the receiving system,

and a drain valve.

[039] In In an an embodiment, embodiment, thethe receiving receiving system system includes includes twotwo pressure pressure indicators indicators at at a front a front endend andand a a

rear end of the receiving system respectively, arranged to monitor a pressure change inside the receiving

system and to avoid any personnel injuries when opening the fast-opening blind valve.

[040] In an embodiment, the receiving system includes a drain pipe to discharge a material from the

receiving system.

[041] In In an an embodiment, embodiment, thethe pipeline pipeline includes includes steel steel barrier barrier bars bars to to help help guide guide movement movement of of thethe pigging pigging

device within the pipeline and prevent the pigging device from being stopped at a corner.

[042] In a second aspect, the present disclosure provides a method of cleaning a pipeline using a

plurality of pigging devices, the method comprising:

providing a plurality of pigging devices, wherein at least one pigging device is of a smaller

diameter, and wherein at least one pigging device is of a larger diameter,

introducing the plurality of pigging devices into the pipeline according to a predetermined

sequence, such that the pigging device with a smaller diameter is used in a pigging operation before the

pigging device with a larger diameter is used to clean the pipeline.

[043] In In an an embodiment, embodiment, thethe plurality plurality of of pigging pigging devices devices include include a first a first pigging pigging device device with with diameter diameter d1,d1,

a second pigging device with diameter d1, a third pigging device with diameter d2, and a fourth pigging

device with diameter d2, wherein d1 1 dd2, d1<d2, andand wherein wherein thethe second, second, third, third, andand fourth fourth pigging pigging devices devices areare

provided the surface formations.

[044] In In an an embodiment, thethe embodiment, step of of step introducing thethe introducing plurality of of plurality pigging devices pigging into devices thethe into pipeline pipeline

comprises introducing the first pigging device into the pipeline first, then followed by the second pigging

device, the third pigging device, and finally the fourth pigging device.

[045] In In an an embodiment, thethe embodiment, step of of step introducing thethe introducing plurality of of plurality pigging devices pigging into devices thethe into pipeline pipeline

comprises:

(a) loading one of the plurality of pigging devices into the pipeline;

(b) using a hydraulic force to push the pigging device into the pipeline at a first end thereof, and

to cause the pigging device to advance from the first end to a second end of the pipeline for pigging

purpose; (c) collecting the pigging device at the second end of the pipeline by a receiving system;

wherein steps (a) to (c) are repeated for each of the plurality of pigging devices.

[046] In an embodiment, the surface formations are formed in a polyurethane outer coating, which is

permanently attached and wrapped around a main body portion of the respective pigging device.

[047] In In an an embodiment, embodiment, d1 d1 is is approximately approximately 10 10 to to 15mm 15mm smaller smaller than than d2,d2, wherein wherein both both d1 d1 andand d2 d2 areare

smaller than a diameter of the pipeline.

[048] In In an an embodiment, embodiment, thethe method method further further comprises: comprises:

determining an effective diameter of the pipeline before a pigging operation is performed,

determining diameters of the plurality of pigging devices, based on the effective diameter of the

pipeline,

wherein the effective diameter of the pipeline is determined based on a diameter of the

pipeline and a thickness of scale built up on an internal wall of the pipeline.

Further

[049] Further features features andand advantages advantages of of thethe present present disclosure disclosure will will become become apparent apparent from from thethe

following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Various

[050] Various preferred preferred embodiments embodiments of of thethe present present disclosure disclosure will will nownow be be described, described, by by wayway of of

examples only, with reference to the accompanying figures, in which:

Figure 1 illustrates a schematic diagram of a pigging system, according to an embodiment of the

present disclosure;

Figure 2(a) shows a cross sectional view of a pigging device, according to an embodiment of the

present disclosure;

Figure 2(b) shows a side on view of a pigging device, according to an embodiment of the present

disclosure;

Figure 2(c) shows a front end view of a pigging device, according to an embodiment of the

present disclosure;

Figure 2(d) shows a back end view of a pigging device, according to an embodiment of the

present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

[051] Figure 1 shows a schematic diagram of a pigging system 10, according to an embodiment of the

present disclosure, being incorporated in an interconnected pipeline system. During normal pipeline

transportation, materials are transported by the interconnected pipelines in the direction indicated in

Figure 1 (i.e. from pipeline 130, to pipeline 100, then to pipeline 140, and eventually to pipeline 150). The

pigging system 10 of the present disclosure is configured to clean a section of the of the interconnected

pipeline system, namely pipeline 100 which has a first end 100a and a second end 100b.

[052] The components of the pigging system 10 will now be described in accordance with exemplary

stages of a pigging operation, as follows:

Step 1: preparation

[053] TheThe first first stage stage of of pigging pigging involves involves preparing preparing thethe system system 10 10 such such that that it it is is ready ready forfor pigging pigging

procedure.

[054] A suitable storage facility, for example a facility including storage tanks, is used to maintain

normal production without stopping upstream equipment during the subsequent pigging operation. A

transfer box is installed between the storage facility and the pump that controls material flow rate into the

interconnected pipelines. During the initial preparation phase, material transfer (for example, slurry)

between the storage facility and the transfer box is interrupted, and process water is filled into the transfer

box, which is then ready to be pumped into pipeline 130.

Step 2: flushing

[055] Depending on the type of materials which were being transported within the pipeline 100 prior to

pigging, it may be necessary to flush a cleaning agent, for example, water, through the pipeline 100 to

remove any remaining materials which are still within the pipeline 100. This process may be continued

until the discharge density reading becomes sufficiently low (for example, zero), which is an indication

that a majority of the remaining materials has been flushed out of the pipeline 100. In some cases, the

flushing step may take 25 mins to half an hour.

Step 3: launching a pigging device by the launching system

Once

[056] Once thethe remaining remaining materials materials have have been been flushed flushed outout of of thethe pipeline pipeline 100, 100, pigging pigging operation operation maymay

start. start.

Cleaning

[057] Cleaning of of thethe pipeline pipeline 100100 is is achieved achieved by by causing causing a pigging a pigging device device 20 20 to to travel travel from from thethe first first

end 100a of the pipeline 100, to the second end 100b, and as the pigging device 20 advances within the

pipeline 100, scales within the pipeline 100 is loosened or peeled off the inner wall of the pipeline 100,

due to physical contact between the pigging device and the scales, thereby achieving cleaning purpose. It

PCT/AU2021/050946 8

should be noted that industrial pipelines vary in many different sizes and forms. For mining operations,

pipelines could extend for a few kilometres, and the diameter of such pipelines could also be very large,

for example, around or over 1 meter. Thus, care must be taken when introducing the pigging device 20

into the pipeline 100 and causing it to move through the pipeline 100, as moving the pigging device 20 too

fast may cause structural damage to the pipeline 100 or injuries to the personnel operating the pigging

system, whereas moving it too slow, or not providing sufficient propelling or pushing force to the pigging

device 20 could result in inefficiencies or causing the pigging device 20 to stop at a point before reaching

the second end 100b of the pipeline 100. To ensure that the pigging device 20 is launched safely and

effectively, in the present embodiment, the pipeline 100 is coupled to a launching system 200 arranged to

load the pigging device into the pipeline 100 and causing it to travel along the pipeline 100 by a hydraulic

force.

[058] As shown in Figure 1, the launching system 200 is fluidly coupled to the first end 100a of the

pipeline 100, and the receiving system 300 is fluidly coupled to the second end 100b of the pipeline 100.

In use, the pigging device 20 is introduced into the launching system 200 via inlet 210, and as it

completes its pigging operation, it is collected at an outlet 315 of the receiving system 300.

[059] The launching system 200 includes a launching pipe 110 including sections that have different

diameters. Preferably, the diameter of the launching pipe 110 at the inlet 210 is greater than the diameter

of the launching pipe 110 at the outlet 220. This will allow the pigging device 20 to be more easily inserted

into the launching system 200 via its inlet 210. To accommodate for the difference in pressure in the

launching pipe 110 caused by changing parameters, a pressure balancing pipe 205 is provided which

creates a separate fluid pathway, between sections of the launching pipe 110 having different diameters.

[060] The launching system 200 further comprises a number of valves 201, 206, 207, 209, 211, which

are selectively opened and closed in a predetermined sequence, in order to build up a pressurised

environment within the launching system 200, and to provide a hydraulic pushing force for the pigging

device 20. A fluid source, such as water, is supplied to the launching system 20 via a main fluid inlet 101

in order to create the pressurised environment. The flow rate of such fluid source is controlled by a pump

(not shown in Figure 1). A pressure indicator 202 is included in the launching system 200 which monitors

the pressure within such that it is maintained within a suitable range to avoid any personnel injuries when

opening and closing the valves mentioned above. Furthermore, air vents 203, 204 are arranged to

release the air inside the launching system 200 when required. A pig passing indicator 212 is located

near the outlet 220 of the launching system 200, to monitor whether the pigging device 20 is approaching

the outlet 220 of the launching system 200 and is about to move into the pipeline 100.

[061] In one embodiment, the launching system 200 is arranged to go through the following steps in

order to provide a sufficient hydraulic force to push the pigging device into the pipeline 100:

(a) First, open drain valve 206 to empty the content of the launching system 200. The other

valves retain closed during this step.

(b) After confirming the reading of the pressure indicator 202 has dropped to zero, open fast- opening blind valve 201, which opens up the inlet 210 of the launching system, and load

the pigging device 20 into the launching system 200 by inserting it into the inlet 210.

(c) Close the fast-opening blind valve 201 and drain valve 206, reduce pump speed, which reduces the flow rate of water being supplied to the launching system 200. In a preferred embodiment, the speed of the pump is reduced to 40-50% of its normal operational

speed.

(d) Preferably, the position of the pigging device is also monitored by a location tracking device which is embedded in the pigging device. The next step involves confirming the location tracking device 25 of the pigging device 20 is operating, then open valve 207 to allow process water to start flowing into the launching system. Next, air vent valve 204 is opened to release any remaining air within the launching system, and process water is feed into the pipeline 100. Then, close the air vent valve 204, open the valve 209 such

that a pathway is opened between the launching system 200 and the pipeline 100, and close the valve 211. After the pig passing indicator 212 detects that the pigging device 20

has moved passed it, the pigging device has successfully entered the pipeline 100 and may start its pigging operation.

(e) Next, the pump speed is slowly and cautiously increased in different stages. In a preferred embodiment, each time the speed of the pump is only increased by around 2 to 5%, and the pipeline 100 inlet pressure is maintained at a level equal to, or less than 1.6MPa, at a flowrate of around 6000 to 6500m3/h. 6500m³/h.

(f) As the pigging device approaches the receiving system 300, the flowrate of the pipeline is

reduced to 2500-3000m3/h. 2500-3000m³/h.

(g) Open the drain valve 206 to discharge all water in the launching system and then close

drain valve 206.

Step 4: pigging

Once

[062] Once thethe pigging pigging device device is is launched, launched, that that is,is, it it hashas left left thethe launching launching system system 200200 andand hashas entered entered

the pipeline 100 which requires cleaning, it is pushed along the pipeline 100 by the hydraulic force from a a back end of the pigging device 20. Due to the physical forces (e.g. friction) between an outer surface of

the pigging device 20, and the scale residue on the inner surface of the pipeline 100, the scale residue is

loosened and/or peeled off from the surface of the pipeline 100, which is then flushed away by the water

flowing in the pipeline 100.

[063] Figures 2(a) to 2(d) show a cross sectional view, a side on view, a front view, and a back end

view of an exemplary pigging device 20 according to embodiments of the present disclosure respectively.

[064] The pigging device 20 includes a main body portion 21, which is of a substantially cylindrical

shape, and a head portion 22 extending from a front end of the main body portion 21, wherein the head

portion 22 is formed in a truncated cone shape. The head portion 22 is aerodynamically designed in a

truncated cone shape such that the resistance encountered by the pigging device 20 as it moves along the pipeline 100 is reduced. To further reduce the resistance encountered by the pigging device 20 as it is moved along the pipeline 100, a plurality of through holes 27 extending in a lengthwise direction of the pigging device 20 are provided in the main body portion 21 of the pigging device. These through holes 27 are arranged to discharge some peeling scales to the back end of the pigging device 20 as it travels. The through holes 27 improve the effectiveness of pigging operation and reduce the risk of the pigging device

20 being stuck in the pipeline 100. In a more preferred embodiment, 4 to 6 of such through holes 27 are

provided in the pigging device.

[065] DueDue totothe thesize size and and the the substantially substantiallycylindrical profile cylindrical of the of profile pigging device 20, the pigging it would device 20,beit would be

appreciated that a number of gripping portions are provided in the pigging device 20, which would allow

easier handling and moving of the pigging device 20. For example, at the back end of the pigging device

20, a channel or recess 23b is formed in the main body portion 21, which provides a suitable gripping or

engaging means for lifting or moving the pigging device 20. Similarly, a channel or recess 23a may also

be provided to the front end of the pigging device 20 as shown in Figure 2(b). To further assist with the

lifting or moving the pigging device 20, additional gripping portions 24a and 24b, such as pulling ropes,

are provided at both ends of the pigging device 20.

[066] Preferably, the pigging device 20 is made from a high density open cell polyurethane foam. The

compression rate of the foam is preferably around 30% to accommodate variation of the diameter of the

pipeline 100 while still having enough rigidness to remove the scales and preventing any damage to the

rubber liner.

[067] In In some some embodiments, embodiments, an an outer outer coating coating 28 28 wraps wraps around around thethe main main body body portion portion 21 21 of of thethe pigging pigging

device 20, as shown in Figure 2(c). The outer coating 28 is formed from polyurethane material and is

generally of a thickness of around 2 to 5mm. In one embodiment, the outer coating 28 is formed

separately from the main body 21 of the pigging device 20, and is permanently attached to the main body

21 prior to a pigging operation. The outer coating 28 is formed such that it provides the pigging device 20

with surface formations that assist in lifting or peeling off the scales as it travels within the pipeline 100. In

one embodiment, the surface formations are formed by cutting out sections of the outer coating 28, and

the cut-outs are generally arranged in an array which extend around a major outer surface of the main

body portion of the pigging device, forming a crisscross pattern.

[068] In order to prevent the pigging device 20 from getting seized, steel barrier bars are installed in all

T-branch pipelines along the pigging pathway of the pigging device 20.

[069] As mentioned above, it is desirable to track and monitor the location of the pigging device 20

during a pigging operation. A location tracking device or sensor 25 is provided in the pigging device 20 to

achieve this purpose.

Step 5: collecting the pigging device

[070] After thethe After pigging device pigging 20 20 device hashas finished itsits finished pigging operation pigging within operation pipeline within 100, pipeline it it 100, will need will to to need be be

removed from the pipeline 100 and collected safely without causing any damages to the system, or

injuring operators that are close by. A receiving system 300 is employed to collect the pigging device 20

at the second end of the pipeline 100, as will be further described below.

[071] Similar to the launching system 200, the receiving system 300 also includes a number of valves

303, 307, 309, 312, 313, 314 which are opened and closed in a predetermined sequence in order to

safely reduce the pressure inside the receiving system 300 before collecting the pigging device 20 at the

outlet 315.

[072] TheThe pigging pigging device device 20 20 maymay be be collected collected as as follows: follows:

(a) After confirming the pipeline 100 is discharging water without scale, indicating that pigging operation has been successful, open air vent 303, valves 313 and 309, and close

valve 314 before the arrival of the pigging device 20. Opening air vent 303 will release the

air within the receiving system 300 and prevent the pressure inside the receiving system 300 from raising too quickly.

(b) After receiving a signal from a location tracking device 301 of the receiving system 300, confirming the pigging device 20 has arrived in the receiving system 300, open valve 314, close the valves 313/309 and open drain valve 312 to discharge the water in the receiving

system 300.

(c) When pressure indicators 302 and 306 show zero, open fast-opening blind valve 307 and pull the pigging device out of the receiving system 300 by engaging rope 24a.

(d) Close the fast-opening blind valve 307, drain valve 312 and air vent valve 303.

[073] In In oneone embodiment, embodiment, steps steps 3 to 3 to 5 above 5 above areare repeated repeated multiple multiple times times until until a desired a desired amount amount of of

scale has been successfully removed. To ensure the effectiveness of pigging multiple times, it is

preferred to use pigging devices which have different configurations. For example, the plurality of pigging

devices may be selected such that at least one pigging device is of a slightly smaller diameter than a

subsequent pigging device, and the smaller pigging device is used first before the subsequent pigging

device is caused to travel in the same pipeline. Further, the plurality of pigging devices may also be

configured such that they have different surface configurations provided by the polyurethane outer

coating. In one embodiment, a combination of smooth and textured outer surfaces may be provided to the

plurality of pigging devices.

[074] In In a preferred a preferred embodiment, embodiment, steps steps 3 to 3 to 5 above 5 above areare repeated repeated forfor a total a total number number of of four four pigging pigging

devices to ensure pigging efficiency. The four pigging devices are configured as follows:

First pigging device has a diameter d1, and does not include any surface formations on its outer

surface;

Second pigging device has diameter d1, and is provided with surface formations;

Third pigging device has diameter d2, where d2 is greater than d1, and is also provided with

surface formations;

Fourth pigging device has identical configurations to the third pigging device.

[075] The four pigging devices are used sequentially (first, second, third and then fourth) to prevent the

pigging devices from being stuck in the pipeline, as well as reducing the risk of damaging the rubber lining

of the pipeline 100. In some embodiments, in order to determine suitable diameters for the plurality of

pigging devices, an effective inner diameter of the pipeline 100 will need to be first estimated or

measured, for example, by isolating a section of the pipeline 100, and inspecting a thickness of the scales

either visually or by using a suitable measuring device. The effective inner diameter of the pipeline 100 is

then determined by subtracting the thickness of the scales from the actual diameter of the pipeline 100. If

a rubber lining is provided to the pipeline, it should be noted that the actual diameter of the pipeline

usually equals an inner diameter of the pipeline minus the thickness of the rubber lining. In a preferred

embodiment, d2 is 10 to 15mm greater than d1, and d2 is also approximately 10-20mm smaller than the

effective inner diameter of the pipeline, to account for the thickness of the scales. For example, if the

pipeline 100 has an effective inner diameter of 1000mm, and the thickness of the scale is estimated to be

around 20mm, then d1 is around 960 - 980 mm, and d2 is around 970mm to 990 mm. In another

embodiment, the effect inner diameter of the pipeline is 975mm, and the thickness of the scale is

estimated to be around 20mm, then d1 is around 955mm and d2 is 965mm.

After

[076] After thethe pigging pigging process process finishes, finishes, thethe pipelines pipelines cancan be be used used to to transfer transfer materials materials again. again.

Example

[077] Sino Iron Project, the world's largest magnetite iron ore project, is located within the mineral-rich

Pilbara region of Western Australia. It has 6 milling production lines and all of them have been put into

operation since 2016. The tailings transfer pipeline is 8.124km in length, DN1000 in diameter (i.e. the

nominal diameter of the pipe is 1000mm, but the actual diameter of the pipe is 975mm with a rubber

liner), and is used to transfer iron tailings slurry from the concentrator to the tailings storage facility (TSF).

The designed capacity of the pipeline is 69 MTA (mega tons per annum). Because of the high corrosion

of the process water, the pipeline has been lined inside by a layer of rubber which is approximately

9.53mm in thickness. After operation for several years, the tailings transfer flowrate was observed to

gradually decrease because of scaling on the rubber liner at the beginning of 2019, resulting in

substantial upstream production loss. With the scaling deteriorating, processing capacity of 67,200 tonnes

of raw ore (equalling to 23,172 tonnes of concentrate at a concentration ratio around 2.9) was lost per

day.

[078] Furthermore, the scaling material on the tailing pipeline contains fibrous material and ultrafine

particles, inter grown together and physically adsorbed on the rubber liners. Acid washing has been tried

without any success due to insolubility of the scale material. Thus, a pigging system was proposed.

[079] One of the issues with the pigging of the tailings transfer pipeline is that the scale is too thick, and

the scale on the top section of the tailings transfer pipeline can be up to 110mm in thickness. If too much

scale is scraped off at one time or if the scale collapses and falls to a lower section of the pipeline, it will

bring about excessive scale material in front of a pigging device, which will absolutely prevent the pigging

device from advancing, resulting in blockage of the pipeline and further causing the breakdown of all the

upstream milling lines. In order to address this problem, it is necessary to disassemble the transfer

pipeline to measure the thickness of the scale, determining the effective inner diameter of the pipeline in

order to select a suitably sized pigging device. A total of four pigging devices were used to remove the

scales within the pipeline, with the first pigging device having a diameter of 955mm, and the diameter of

the subsequent pigging devices are incremented by 10mm each time, until it reaches the inner diameter

of the rubber lined pipe, which is 975mm in this instance due to the rubber lining. This measure ensures

that the scale scraped off each time will not be too excessive and the pigging device will not be easily

blocked by the peeled off scale.

Routine

[080] Routine pigging pigging cleaning cleaning by by temporarily temporarily switching switching normal normal slurry slurry transfer transfer mode mode to to pigging pigging

operation without any interruption of processing production is conducted to ensure enough tailings

transfer capacity for normal upstream production. For normal operation of tailings slurry transfer in the

Sino Iron, the tailing slurry is pumped through pipelines 130, 100, 140, 150, to maintain the daily

production of the whole beneficiation plant. Generally the throughput of the tailing slurry is 6700-7500m3/h 6700-7500m³/h

and the slurry density is 45%-55%. Every three months, the throughput will decrease by 200-1200m3/h 200-1200m³/h

due to scaling of mainly minerals in fibrous form and ultrafine particles below 10um. 10µm.

[081] In the Sino Iron Project, various sections of the pipelines are descaled using the systems and

methods described above. After pigging operations, the throughput of the pipeline recovers to its original

value with an increase of the throughput by about 200-1200m3/h. 200-1200m³/h.

In this

[082] In this

[082] specification, specification, the terms the terms 'comprises', 'comprises', 'comprising', 'comprising', 'includes', 'includes', 'including', 'including', or similar or similar terms terms are are

intended to mean a non-exclusive inclusion, such that a method, system or apparatus that comprises a

list of elements does not include those elements solely, but may well include other elements not listed.

[083] TheThe above above description description relating relating to to embodiments embodiments of of thethe present present disclosure disclosure is is provided provided forfor purposes purposes

of description to one of ordinary skill in the related art. It is not intended to be exhaustive or to limit the

disclosure to a single disclosed embodiment. As mentioned above, numerous alternatives and variations

to the present disclosure will be apparent to those skilled in the art from the above teaching. Accordingly,

while some alternative embodiments have been discussed specifically, other embodiments will be

apparent or relatively easily developed by those of ordinary skill in the art. The present disclosure is

intended to embrace all modifications, alternatives, and variations that have been discussed herein, and

other embodiments that fall within the spirit and scope of the above description.

Claims (21)

1. A pipeline pigging system including:

a pipeline used for material transportation, wherein the pipeline includes a rubber lining;

at least one pigging device, arranged to be introduced into the pipeline at a first end of the pipeline, and caused to travel in the pipeline for pigging purpose between the first end and a second end 2021461615

of the pipeline;

a launching system, for introducing the at least one pigging device into the pipeline at the first end, and

a receiving system for collecting the at least one pigging device at the second end of the pipeline after descaling,

wherein the at least one pigging device includes one or more bores which extend in a lengthwise direction of the at least one pigging device, allowing a material to move from a front end of the at least one pigging device to a back end of the at least one pigging device and be discharged therefrom as the at least one pigging device travels within the pipeline.

2. The system of claim 1, wherein a diameter of the at least one pigging device is smaller than a diameter of the pipeline.

3. The system of claim 1 or 2, wherein the at least one pigging device further includes a head portion formed in a truncated cone shape, and extends from one end of a cylindrical main body.

4. The system of any one of claims 1 to 3, wherein the at least one pigging device is made from compressible materials, the compressible materials having a compression rate of about 30%, that is, the diameter of the at least one pigging device is able to be reduced by about 30% when it is compressed.

5. The system of any one of claims 1 to 4, wherein the at least one pigging device includes a polyurethane outer coating, wherein the outer coating comprises surface formations that assist in lifting or removing the scales as the at least one pigging device travels within the pipeline.

6. The system of claim 5, wherein the surface formations include raised structures which are evenly distributed around an outer surface of the at least one pigging device.

7. The system of claim 5 or 6, wherein the polyurethane outer coating is of a thickness of 2 to 5 mm.

8. The system of any one of claims 1 to 7, wherein the material includes water, or build up of materials removed from an inner surface of the pipeline.

9. The system of any one of claims 1 to 8, wherein the at least one pigging device includes a location tracking device, enabling positions of the at least one pigging device to be detected and forwarded to an electronic position receiver.

10. The system of any one of claims 1 to 9, including a plurality of pigging devices which are of 2021461615

different diameters and/or surface formations and are arranged to be introduced into the pipeline in a predetermined sequence.

11. The system of claim 10, wherein the plurality of pigging devices include four pigging devices: a first pigging device with a first diameter d1, a second pigging device with diameter d1, a third pigging device with a diameter d2, and a fourth pigging device with diameter d2, wherein d1<d2, and wherein each of the second, third, and fourth pigging device is provided with a polyurethane outer coating with surface formations.

12. The system of any one of claims 1 to 11, wherein the launching system includes an inlet, into which the pigging device is inserted, an outlet coupled to the first end of the pipeline to be descaled, and a launching pipe extending between the inlet and the outlet of the launching system.

13. The system of claim 12, wherein the launching pipe includes sections which are of different diameters.

14. The system of claim 12 or 13, wherein a diameter of the launching pipe at or near the inlet is greater than a diameter of the launching pipe at or near the outlet.

15. The system of any one of claims 1 to 14, wherein the launching system further includes a pressure balancing pipe, which balances pressure changes between sections of the launching pipe which are of different diameters. .

16. The system of any one of claims 1 to 15, wherein the launching system further includes: a fast opening blind valve, a pigging device passing indicator, a pressure indicator, an air bleed and an air vent, and a drain valve.

17. The system of any one of claims 1 to 16, wherein the receiving system includes: an inlet, being coupled to the second end of the pipeline to be descaled, an outlet, from where the pigging device exits and is collected, a receiving pipe extending between the inlet and outlet of the receiving system.

18. The system of any one of claims 1 to 17, the receiving system further includes: a fast-opening blind valve, a pigging device passing indicator arranged to track the location of the pigging device within the receiving system, pressure indicators, an air bleed and an air vent arranged to release the air inside the receiving system, and a drain valve.

19. The system of any one of claims 1 to 18, wherein the receiving system includes a drain pipe to discharge a material from the pipeline. 2021461615

20. The system of any one of claims 1 to 19, wherein the pipeline includes steel barrier bars to help guide movement of the at least one pigging device and prevent the at least one pigging device from being stopped at a corner.

305 P SLEED BLEED

304 AIR AIR 312 312

CO OF VENT VENT 303 303 AIR AIR

302 150 150

301 a 310 310 Z 311

314 313 313 309

100b

PSE 140 308 308 Figure Figure 11

S *

103 103 PIT

100 100

102 PIT PIT

211 100a 100a

209 209

208 202 203 204 205 212

212 130 220

220

ZI 205

Z 207 206

206 130

DOI 204 VENT VENT

AIR AIR

DE 207

BLEED BLEED

203 AIR 110 110 (3)

202 di

P 101

210 210

201 200 200

SUBSTITUTE SHEET (RULE 26) RO/AU

Figure 2(d) Figure 2(d)

Figure Figure 2(b) 2(b)

BY

23a 23a

23b

24a 24a

24a 24a

22 27

28

Figure Figure 2(c) 2(c)

21 Figure 2(a) Figure 2(a)

23b

24b 24b 24b

SUBSTITUTE SHEET (RULE 26) RO/AU