A Commercial Slurry Pipeline Engineering Essay

In his article Slurry Pipeline Design for Operation with Centrifugal Pumps, G. R. Addie stated that Slurry grapevine engineering is highly complex, and non a to the full understood scientific discipline. This assignment has for aim to picture and research the proficient facets involved and related to the design of grapevines and pumping systems for the conveyance of slurries.

Compared to other technology engineerings, the design of a commercial long distance Slurry

Pipeline design is classed as a comparatively new technology pattern which started in the mid 1960 ‘s. Slurry grapevine was foremost introduced to cut down cost in transporting coal to power bring forthing units. Since so this engineering has caught-up worldwide to transport other minerals such as limestone, Cu, Zn and Fe. In South America, the usage of grapevine is normally practiced in the conveyance of Copper ( Chile and Argentina ) , Iron ( Chile and Brazil ) , Zinc ( Peru ) and Bauxite ( Brazil ) . As more excavation operations expand and new mine installations are opened, the design of the long distance slurry grapevine will continuously show a commercially feasible option.

For illustration, in Coal excavation, a slurry grapevine will affect the pumping of finely ground coal suspended in H2O or other liquid medium through a pipe over a long distance. At the end point the coal and liquid are separated and the coal is prepared for burning or other usage. The primary rail rival of slurry grapevines is the unit train, a complete train of dedicated autos runing on a on a regular basis scheduled motion between a individual beginning and a individual finish.

In this assignment, the writer will be looking at slurry grapevines in general, hardware required in the scene up, edifice and their care. Rules, ordinances, environmental, economic viability and societal impact will be discussed. More countless factors such as the nature of slurries ( settling and non-settling ) including non-Newtonian behavior, will be explored throughout the advancement of the study.

A COMMERCIAL SLURRY PIPELINE

There are two general groups of slurries: non-settling or settling types. Non-settling slurries have a larger spectrum of really all right atoms organizing stable homogenous mixtures with increased viscousness. These slurries are gentler to the interior surface and liner of grapevines. Due to their low erosion belongingss, non-settling slurries requires careful consideration when choosing the right pump and thrust, because they frequently do non act in the mode of a normal liquid. When all right solids are present in the slurry in sufficient measure to do this alteration in behavior off from a normal liquid, they are referred to as being non-Newtonian ( Warman Slurry Pumping ) .

Coarser atoms ( bigger diameters ) form an unstable mixture and sort as settling slurries. This makes them harder to switch and pump applied scientists have to pass more clip on computations and make up one’s mind on a reasonable attack to flux and power. Bigger and coarser atoms have higher erosion belongingss and organize the bulk of slurry applications. This type of slurry is besides referred to as being heterogenous.

One of the most of import characteristics to see when constructing a grapevine is the demand for continuity for medium to long distance conveyance. Features such as flow rate, force per unit area, concentration, size distribution are cardinal. At present, for the excavation industries, slurry grapevine is normally used in the conveyance of mineral ore, dressed ore or shadowings. In the conveyance of dressed ore, a typical system will include a mine, an agitated storage provender armored combat vehicle, a pumping station, the grapevine and a receiving terminus. In some instances, a valve station and force per unit area monitoring station is included for improve grapevine operation ( Bettinol et al, )

DESIGN CONSIDERATIONS

CONCEPTS OF MATERIAL SELECTION

When it comes to choosing stuffs and types of stuffs for a commercial slurry grapevine, applied scientists, mining companies and pump makers face a batch of restraints. The process must first history for all the factors ( variable features ) of the peculiar slurry. The challenges that may originate from conveying slurries will give us an indicant on taking a type of pump, pump velocity for both homogenous and heterogenous slurries, and take the right pump from a scope of the theoretical accounts available.

Choosing the right pump, pump liner and stuffs for the grapevine will depend on the atom size of the solids to be pumped, the form and hardness of these solids, and the caustic belongingss of the “ liquid ” constituent of the slurry to be pumped.

hypertext transfer protocol: //www.weirminerals.com/products/piston_pumps.aspx

CHOOSING THE RIGHT PUMP

The pumps used to drive the slurry along the grapevine must be robust, dependable, and of proved public presentation. For long grapevines, the choice of pick is the positive-displacement pump. Whereas centrifugal pumps are limited by the maximal shell force per unit area, typically about 7 MPa or 700 m caput, positive-displacement pumps can supply pressures up to 25 MPa. Piston wear is decreased by the usage of Piston stop pumps. The stop protects the Piston and line drive from scratchy skiding contact wear. The conveyance system from slurry readying country to refinery consists of a long steel grapevine and high-pressure pumps. To pump big measures of bauxite requires particular considerations to keep a high degree of dependability in this individual “ life line. ” It is indispensable to hold a Piston Diaphragm Positive Displacement pump, as the impellers, being the chief rotating constituent, offer a “ vane ” profile to bring forth adequate force to drive the liquid.

( warman slurry pumping )

Slurry Impellers exist as closed and unfastened types. Closed type Impellers ( with a front shroud ) are preferred as they have a higher efficiency, and are less prone to have on and rupture. The throw outing vanes on the dorsum and forepart shrouds of a slurry impeller aid in cut downing force per unit area. The recirculating flow back is restrained and the pumping force per unit area controlled. The vanes besides keep the solids or oversized atoms out of the spreads found between the shell and the impeller.

Solids debasement by atom abrasion through the pumps and grapevine could alter the fluid rheology, which, in bend, could impact pumping by asking a higher hydraulic caput and more power. Opportunities for the happening of stoppers and leaks need to be mitigated by a design that reduces the hazard of such events. A high grapevine speed has to be maintained to forestall solids from dragging on the underside of the pipe in a state of affairs called “ inchoate sanding, ” . This can increase pipe wear, cut down grapevine life, and lead to a higher pumping head demand as a consequence of the reduced flow cross-section, but well reduced by the usage of Piston Diaphragm pumps.

When planing a grapevine for the slurry devastation system chiefly has to see about wear, corrosion, transient and steel class. Erosion of the inside surface of the pipe is a chief job when pumping slurries. To get the better of this issue, the pipe is either lined or provided with extra wall thickness. Elastomers and wear/erosion immune dramatis personae metals can be used. However utilizing all right atoms will let pretermiting eroding of the pipe. Interior corrosion is hard to foretell but must be allowed for if no liner is used. One method to cut down corrosion of steel pipes is to raise the pH by adding calcium hydroxide. ( http: //www.mrwa.com/OP-Corrosion.pdf accessed 18/02/2013 )

The exterior can be protected by utilizing cathodic protection system. Besides grapevine internal diameter become important for long term public presentation of the system. The diameter will make up one’s mind with the minimal slurry speed to forestall solid subsiding. Using smaller diameter will increase the force per unit area caput. Besides when sing the hardware of shrieking system several valves and adjustments have to be considered. Such as insulating valves, scour valves, and air valves. Pressure proctors and magnetic flow recording equipments are installed as portion of the monitoring/leak sensing system. Air valves and scour valves facilitate emptying subdivisions of grapevine and capturing the associated slurry in shit pools. If these valves are non provided, pull offing line interruptions or obstructions could be ambitious, peculiarly in really long grapevines. Dump pools can utilize to pin down and incorporate slurry if it becomes necessary to pull off interruptions and line obstruction.

Part B

Location and Selection of a mine

The Sino Iron Project is a coaction between the Chinese and Australia. The Mine and slurry grapevine are rather distant and located about

Due to its remote location 1200 kilometres North of Perth in Western Australia, the client CITIC Pacific Mining Management Pty Ltd required the development of dedicated substructure to back up the USD3.5billion greenfields sino Fe undertaking.

The graduated table, complexness and part to regional substructure sets the undertaking apart.A It comprises of mine operations, ore dressed ore works, 25km slurry grapevine presenting merchandise to port, concentrate filter, 6 million metric ton pelletising works, stockyard and material managing systems, 450MW gas-fired powerA station, 51gigelitre desalinization works, power transmittal and transforming installation, H2O supply web in works country, adjustment, new port and transhipmentA installations.

The Australian subordinate of the Chinese EPC Contractor, MCC, is presenting the substructure associated with the undertaking. GHD has been appointed to help MCC ‘s chief design contractor, NETC ( based in China ) to reexamine their designs for conformity with Australian and West Australian criterions. GHD is besides set abouting the structural design computations and hazard analysis for theA undertaking, every bit good as shadowings dam stableness and a safety analysis reappraisal.

HYDRAULIC DESIGN

The sequence followed for the hydraulic design of a paste or thickened shadowings grapevine system is:

i‚· Select the pipe diameter ( and test pipe wall thickness ) sing deposition and laminar subsiding

standards ( Cooke, 2006 ) .

i‚· Calculate the unit clash losingss.

i‚· Plot the hydraulic class line for steady province operating conditions.

i‚· Check that the pipe force per unit area evaluation meets the steady province force per unit area envelope, if necessary change the pipe specification and reiterate the above stairss.

i‚· Determine the hydraulic class line envelope for transeunt conditions ( grapevine get down up, shut down,

flushing, etc ) . This may necessitate a alteration to the pipe specification and a repetition of the above stairss.

i‚· From the hydraulic class line, find the pump station responsibility caput envelope.

i‚· Select and stipulate the pump ( s ) required for the pump station.

i‚· Check the operating point stableness by plotting the grapevine and pump caput versus flow rate curves

( required for centrifugal pump systems ) .

i‚· Check that the pump suction force per unit area is sufficiently high to avoid cavitation.

Part C

Make slurry pipelines stand for a less dearly-won manner to travel coal?

If one ignores regulative deformations and larger societal costs, slurry grapevines can, harmonizing to this analysis, conveyance coal more economically than can other manners under certain fortunes. The undermentioned conditions tend to favor grapevines on any peculiar path:

High one-year volumes of coal shipped.

Long distances to be traversed.

High anticipated rates of rising prices.

Low involvement rates.

Large closely separated mines.

A secure market of several big clients located in such a manner as to allow them to have coal from a individual

grapevine.

Terrain features favorable to grapevine digging and building.

Handiness of sufficient H2O at low delivered cost.

Low cost of electric power for grapevine pumping comparative to that of Diesel fuel for railway engines.

Circuitous rail paths, hapless path, or other conditions unfavorable to railwaies.

Inefficient rail operations, including short or slow trains.

Absence of a parallel navigable waterway.

The pick of grapevine transit over rail represents in portion a determination to incur capital costs, which can be amortized at a predictable rate, instead than operating costs, which are capable to rising prices. This common concern determination involves weighing the existent involvement rate one must pay on invested capital against the unsure rising prices constituent of future operating disbursals. Comparisons of rail and grapevine economic sciences in this analysis are based on entire life rhythm costs, and they take the greater exposure of rail disbursals to rising prices into history. However, directors of electric public-service corporations, which represent possible clients for slurry grapevines, perceive an advantage in greater stableness every bit good as lower overall degrees in transit duties.

The necessity to foretell future building costs, labour productiveness, and rising prices rates adds a major component of uncertainness to the comparative costs of the two manners. In fact, the scope of uncertainness associated with anticipations of rail and grapevine costs in a given instance is frequently every bit great as the difference between them. Pipeline funding requires long-run purchase contracts with clients, which embody important hazard given the trouble in calculating the hereafter. Since the costs of mistakes in judgement will likely be borne mostly by the populace and non needfully by the public-service corporation investors, regulative bureaus regulating public-service corporations should therefore scrutinize long-run contracts for grapevine transit with great attention.

If grapevine economic sciences do ensue in nest eggs, the benefit will accrue to the coal excavation, electric public-service corporation, and grapevine industries. Regulatory mechanisms can do nest eggs in the transit and public-service corporation sectors to be passed on to consumers. The excavation industry is non likewise constrained by ordinance, but competition may Iimit additions in excavation grosss.

Economic conditions favoring grapevines or railwaies are present to changing grades at different times and locations, and since the finding of cost advantages entails considerable guesss for the hereafter.

To find the most economical grapevine system to utilize, it is of import to see location

of installations, the grapevine path, features of slurry and sum of solids ( throughput ) to

conveyance. The combination of these parametric quantities defines the economic viability of the grapevine

conveyance system. In position of these, each parametric quantity will be discussed briefly to understand its

impact for a safe and economic grapevine design.

Facility Location

This refers to the location of the works installation as the grapevine beginning to the having terminal which could be a dike or a filter works. The comparative location between these two installations will order the hydraulic caput required for the conveyance system. In most instances, the choice of the

location of these installations is driven by political, economic and environmental demands.

Pipeline Route

This is the most of import facet of the grapevine conveyance design which could specify the

beginnings or terminal of the undertaking. Theoretically, the most economic path would be one with a

uninterrupted 1 % downgrade and traverses the most direct path as possible with no intermediate high points ( see Figure 4 ) . This nevertheless is barely seen in pattern. Therefore, it is the aim of the interior decorator to choose a path that closely assimilates the theoretical status. The grapevine path choice will necessitate the expertness of both the hydraulic applied scientist and the building specializer. For slurry grapevine, it is the concern of the hydraulic applied scientist to happen the shortest path ( lower force per unit area losingss ) , the least incline ( for easiness in operation and care ) and one with most consistent lift ( for low pumping caput ) . It is the purpose of the building specializer to measure constructability of the path minimising river or creek crossings and avoiding landslides that could be destructive to the grapevine. He besides needs to quantify and minimise building in rocky or difficult dirt formations.

The Sino Iron Project is Australia ‘s first major magnetic iron-ore undertaking and the 2nd largest undertaking presently under building in the Pilbara.

Due to its remote location 1200 kilometres North of Perth in Western Australia, the client CITIC Pacific Mining Management Pty Ltd required the development of dedicated substructure to back up the USD3.5billion greenfields sino Fe undertaking.

The graduated table, complexness and part to regional substructure sets the undertaking apart.A It comprises of mine operations, ore dressed ore works, 25km slurry grapevine presenting merchandise to port, concentrate filter, 6 million metric ton pelletising works, stockyard and material managing systems, 450MW gas-fired powerA station, 51gigelitre desalinization works, power transmittal and transforming installation, H2O supply web in works country, adjustment, new port and transhipmentA installations.

The Australian subordinate of the Chinese EPC Contractor, MCC, is presenting the substructure associated with the undertaking. GHD has been appointed to help MCC ‘s chief design contractor, NETC ( based in China ) to reexamine their designs for conformity with Australian and West Australian criterions. GHD is besides set abouting the structural design computations and hazard analysis for theA undertaking, every bit good as shadowings dam stableness and a safety analysis reappraisal.