49316 materials handling System design for transport of limestone to feed a cement plant at the foot of the Himalayas |
Assignment 3Parviz Raminzad |

49316 materials handling System design for transport of limestone to feed a cement plant at the foot of the Himalayas |
Assignment 3Parviz Raminzad |

Contents Q2) Relevance of System Engineering to bulk materials handling and this project 3 Q3) Alternative Systems 4 Rail and Road 4 Aerial Ropeway 4 Building the Cement Plant near the Mine Site 4 Pipeline 4 Q4) Discuss the purpose of the items in Figure1 5 Q5) Discuss the purpose of Rheological and Flow test 15 Purpose of Rheological and Flow Tests. 15 Importance of Pilot Plant Tests 16 Q6) Design Selection 17 a. Delivery Pipeline 17 Quantity to Be Pumped 18 Size of Pipeline 19 Friction Head Hf for the Pipeline 19 Loss in Discharge Pipe Enlargement 20 Loss at Pipe Discharge 20 Loss of Head at Entrance to Suction Pipe 20 Total Dynamic Head on the Pump [Hm] 21 Equivalent Water Total Dynamic Head [Hw] 21 b. Warman Pump Selection 21 Piston Pumps and Pipe Validation 22 a. Piston Pumps 22 b. Pipe Design Parameters 23 8) Design Parameters of the main pipeline 23 Q9) Alternative Systems 26 References: 27

Q2) Relevance of System Engineering to bulk materials handling and this project

Systems engineering is a methodical, disciplined approach for the design, realization, technical management, operations, and retirement of a system. A “system” is a construct or collection of different elements that together produce results not obtainable by the elements alone. The elements, or parts, can include people, hardware, software, facilities, policies, and documents; that is, all things required to produce system-level results. The results include system-level qualities, properties, characteristics, functions, behaviour, and performance. The value added by the system as a whole, beyond that contributed independently by the parts, is primarily created by the relationship among the parts; that is, how they are interconnected. It is a way of looking at the “big picture” when making technical decisions. It is a way of achieving stakeholder functional, physical, and operational performance requirements in the intended use environment over the planned life of the systems. In other words, systems engineering is a logical way of thinking. (handbook, NASA Systems Engineering, n.d.)

The vital role of system engineering in this project includes efficiency and certainty assurance of transporting of limestone in slurry form from the mining site to the cement manufacturing plant in dry state and also considering the climate and large distance between the two plant and the position of the mining site at the top of the Himalayas. In order to achieve this, there are many sub processes such as crushers, pumps, Storages etc… which have to be carried out precisely along the way. These require a very well planned, accurate and complicated system design.

Q3) Alternative Systems

Based on the article from Bulk Solid Handling Vol 4 No 3, Sept 1994 page 583 to 588 (S.R. Basu and A.K. Saxena, India) there were several different alternatives to do this project:

Rail and Road
Both of these options are not real options due to the tract between the two plants is hilly and rugged terrain, plenty of landslides are experienced in the past and a lot of deforesting would be involved, so it will be so expensive or next to impossible to build road or rail tracks.

Aerial Ropeway
Despite aerial ropeway being a great option for this sort of projects (mountain areas) the distance between the two plants is too big for this option to be considered. About 400 towers are needed to handle this volume of material. Low Tech Magazine (De Decher, 2011)

Building the Cement Plant near the Mine Site
Since roads or rails are needed to transport the building material to the site to build the plant this option for the same reason above is unrealistic.

Pipeline
Considering all the options above a Pipeline (Slurry) transportation system would be the most suitable solution for our project. It is quite ideal for transporting limestone in long distances, and it has been done and tried before.

Q4) Discuss the purpose of the items in Figure1

1. Primary Crusher

The primary crusher is used to break limestone extracted from the mine to smaller and more consistent sizes suitable for the next stage. The most common crusher used for limestone is jaw crusher which a sample can be seen below.

http://modularmachines.co.in/uploads/images/1s.jpg

2. Intermediate Storage

Crushed limestone is move to this point by conveyor to be temporarily stored and used as a buffer to feed the rotor impactor hammer to be crushed further.

http://i.ytimg.com/vi/LfGUjiMhXI4/hqdefault.jpg

3. Sampling and Measurement

Hammered limestone gets sorted by going through a screening process which is normally by using mesh with the required size holes. The larger particles are separated and fed back to the hammer to be reprocessed.

http://www.majorwire.cc/main/sites/default/files/proven-solutions/Casey_0.JPG

4. Impact Hammer

Limestone gets crushed to even smaller particles to suit the next stage of the process (Ball mill). As seen on the pictures below limestone gets repeatedly hit by bouncing backward and forwards between the rotor and the internal lining.

http://i00.i.aliimg.com/img/pb/110/660/295/295660110_855.jpg

http://www.usinenouvelle.com/industry/img/mineral-processing-impact-hammer-mills-000127451-4.jpg

5. Ball Mill

At this stage limestone coming from the storage bin and water are fed into the ball mill. As shown in picture below Materials enter evenly into the first storehouse from feeder though the empty tube in a spiralling way. There are stepped lining plate and corrugated plate in this house which is equipped with different kinds of steel balls. The steel balls are lifted at a certain height with centrifugal force producing by running tube and fall down. The moving steel balls hit and grind materials during such process. The materials are coarse crushed in the first storehouse, then they enter into the second storehouse though single-wall partition. There are steel balls

and a plane liner in the second storehouse which will further grind the materials. The powder material is discharged from exit plate. Then the whole grinding line finishes. (Modular Machines co, n.d.) The output is in a slurry form ready to be filtered again and pumped out.

http://modularmachines.co.in/uploads/images/20140910190625_7500.jpg

6. Slurry Pump and Recycle Circuit

The slurry pump pressurizes the slurry coming out of the ball mill and pumps into the cyclone. As it says in the name a cyclone is created in the cyclone separator by generating a high RPM rotating slurry in order to filter the lighter particles (sitting on top) from the heavier ones (going down to the bottom).Then the lighter parts are sent to be processed further and the heavier particles get pumped back to the ball mill.

https://encrypted- tbn3.gstatic.com/images?q=tbn:ANd9GcT6h14l3KExmsOaCvpFOZbwYH_DNql62NsoYsK6fqpR6WEVKc64Gg

http://exaircorp.files.wordpress.com/2013/09/cyclone.gif

7. Agitated Storage Tanks

The main role for these tanks is to store the slurry and act as a buffer to be pumped by booster pumps into the main pipeline to be delivered to the cement factory. In the meantime these tanks stop any settlement of the particles to avoid any problem with pumping the slurry along the long distance.

8. Main Line Pumps
These pumps in conjunction with piston pumps are used to pump the slurry to the agitated tanks in the factory.

9. Filtering
At this stage the lime stone particles are separated from the slurry

10. Clarifying and Drying Equipment

In clarifying process the water extracted from the slurry gets treated to be reused commercially or in some other industries. Some possible left over lime stone particles are also separated and sent back to the filtering process.
A kiln using hot gases is used in drying process to dry out the lime stone to get ready to be sent out to cement manufacturing unit. The hot gets filtered and released into the atmosphere. Q5) Discuss the purpose of Rheological and Flow test

Purpose of Rheological and Flow Tests.
To determine the properties of fluid, solid and both combined as well as finding important properties as size, viscosity and shear stress rheological and flow test are carried out. All of these tests are to help us find the best possible way to transport the limestone through pipeline avoiding any flow disruption. Some of the important properties tested on this paper are: 1. Unhindered settling velocity of solid particles 2. Slurry specific gravity at various concentrations 3. Slurry viscosities at various concentration 4. Specific gravity of solids 5. Angle of response of slurry 6. Particle shape 7. Chemical composition of solids 8. Particle size distribution Different sizes of samples were used for the laboratory testing in order to create a similar heterogeneity with the one in the actual distribution. The graphs which have been made with the results are: * Size vs. cumulative percent retained * Concentration by weight vs. specific gravity of slurry

Importance of Pilot Plant Tests
Building a pipeline is a very expensive practice. Pilot plant tests are real necessities since they help us making critical decisions by providing: * An estimate of material real behaviour in the whole system * Identify the undesirable behaviour of material which could harm the system * Verify if the pipeline is a suitable option for the life cycle of components * Guide line to calculate and select machinery

Q6) Design Selection a. Delivery Pipeline
Provided information:

Cw=0.55 Circulating load back=125% Zd=22 m Zs=positive 4 m Valves=4 Long Radius Elbows=4 Estimated length of Pipe=32 m Feed Pressure to Cyclone=250 kpa

The best Cw chosen for the proposed pipeline was 0.55(based on pilot test). Based on table 2 and figure 4 (Basu & et.al., 1984) , material properties are:

S=2.89 Average Particle Size=170 meshAverage Particle Size=0.088 mm

Volume of material and hours:

Annual Throughput=2*106 ton/yearAnnual Operating Time=6000 h

With that we can obtain the flow but considering the circulating load back:

m=2*1062.25 tonyear=1 year6000hr=148.15tonhr

Quantity to Be Pumped
Weight of solids in slurry: Ws=148.15 ton

The weight of volume of water equal to solids volume: 148.152.89=51.3 ton

The weight of water in slurry of Cw=55% Ww=148.15 ton100-5555=121.2 ton

The total weight of equal volume of water: 121.2 ton+51.3 ton=172.5 ton

The total weight of slurry mixture: 121.2 ton+148.15 ton=269.35 ton

The specific gravity of slurry mixture Sm=269.35 ton172.5 ton=1.56

The concentration of solids by volume Cv=100172.5 ton51.3 ton=29.74%

Finally the quantity of Slurry taking into account 1m3 of slurry = I ton: Q=121.2m3hr1000[l]1[m3]1[hr]3600[s]=33.7 litre/Sec

Size of Pipeline
To stop the material settling and keep flowing a 125[mm] pipeline as minimum is considered.
The slurry velocity
V=Q*1273d2=33.7*12731252=2.74 m/s
The limiting velocity based on Durand’s Equation in Warman catalogue will be:
VL=FL2gDS-SISI
FL from figure 4-5-2 of Warman catalogue (Warman International Inc., 1968)
FL=0.9
VL=0.929.810.1252.89-11=2.12 m/s
Since the limiting velocity is lower than the slurry mixture velocity 125 mm pipe is suitable.

Friction Head Hf for the Pipeline
Obtaining the head losses of valves and fittings on figure 4-4-3 (Warman International Inc., 1968)
Actual length of pipe=32 m
4 x long radius elbows=13.4 m
Equivalent length of the line=45.4 m
Based on pipe size of 125mm and a slurry mixture velocity of 2.74 m/s and table 4-3-2 f=0.017 By using Darcy’s Equation Hf is:
Hf=fLD∙V22g=0.01745.4m2.74ms220.125m9.8ms2=1.97m

Loss in Discharge Pipe Enlargement
The assumption is a pipe enlargement from 100mm to 125mm so we calculate V with 100mm
V=Q*1273d2=33.67 l/s1273100mm2=4.29 m/s

The head loss assuming an angle of 30deg and using the formula in figure 4-4-4 keV-V122g=0.554.29ms-2.74ms229.81ms2=0.067m Loss at Pipe Discharge
The velocity head
V22g=2.74 229.8=0.38 m

Loss of Head at Entrance to Suction Pipe
Based on being similar to the discharge 125[mm]
0.5V22g=2.74 m/s249.81 m/s=0.19 m

Total Dynamic Head on the Pump [Hm]
Based on information obtained from figures 4-4-1 and 4-4-2 (Warman International Inc., 1968)
Hm=Zd-Zs+Hf=22-4+1.97+0.067+0.38+0.19
Hm=20.6m

Equivalent Water Total Dynamic Head [Hw]
Next equation is to obtain Hw:
Hw=HmHR
HR is obtained from figure 2-3 (Warman International Inc., 1968):
HR=0.92
Hw=20.60.92=22.4m

b. -------------------------------------------------
Warman Pump Selection

Based on this info the pump is chosen figure 3-4 of the Warman catalogue:
Q=33.67 l/s Hw=22.4m SG=1.86
From figure 3-4 a Warman 6/4 D-AH Heavy Duty rubber lined pump is selected with a 5 vane closed rubber impeller at a speed of 975 rpm with an efficiency of 60%
The power consumption is:
P=Q∙Hm∙Sm1.02∙ew=33.67 l/s20.6m1.861.0260=21[kW]

On the safe side a 25kW drive motor is selected.

Piston Pumps and Pipe Validation

a. Piston Pumps

Calculating an approximate for the piston pumps, assuming that our pumps are centrifugal pumps (Pentair Flow Technologies, 2015)
HP=GPM*PSI1710ew SG

Obtaining GPM
33.67 ls=0.2641[gal]1[l]60[s]1[min]=533.7[GPM]
P=30.7[HP]
PSI=1710 HP ew SGGPM=171030.7[HP]0.601.86533.7[GPM]
PSI=109.8[psi]

We have 32m of travel, therefore we need 3 piston pumps to cover the 78km.

b. Pipe Design Parameters

As per the article the pipe diameter of 200mm and the length of 78km
Q=33.67 l/s

The slurry mixture velocity
V=1273∙Qd2=33.6712732002=1.07 m/s

From figure 4-3-2 we obtain the friction factor f f=0.0158 Hf=fLD∙V22g=0.0158780001.07220.29.81=360.6m

8) Design Parameters of the main pipeline

Annual through output The amount of annual slurry to be transported is 2 x 106 ton.
Operating time
Our design is based on the total time of 6000 hours of transportation per year.
Pipeline
Based on the annual through output and operating time, we design a pipeline to handle this load.

Pressure loss model
The problem of friction arises once the limestone slurry is moving through the pipeline .To reduce or eliminate this problem pressure loss models are used based on the given data. Particle size
The Maximum and minimum of lime stone particles are 60% of 170 mesh and 85% of 100 mesh respectively. This is used as a key factor in our design.
Pipeline diameter
200mm of internal dia pipe would give us the optimum flow of the limestone particles.
Slurry consistency
Slurry consistency is important to factor that determines the flow of slurry. As observed in the rheological and flow tests carried out in the pilot plant, the consistency of slurry changes when there is an increase in concentration of solid particle in the slurry and will require more pressure to move the slurry through the pipelines.
Velocity of flow
When the flow velocity is low, the graph is curved but as the flow velocity increases, the graph becomes linear as seen in the rheological and flow tests. This is due to , the slurry is a non-homogeneous mixture at low velocities, however at higher velocity.
Slurry pH
The pH of the slurry plays an important role in determining and extending the life of the pipes since it could cause corrosion.
Wear rate
The obvious outcome of friction between slurry and pipelines is wear, which can cause a great reduction on the equipment life time. By controlling the flow rate of the slurry this can be controlled.
Rotary impact hammer crusher
The impact hammer has a capacity of 450 tons per hour an output of 30 mm limestone particles. The incoming feed is 150 mm limestone.
Ball mills Ball mill is used to grind the limestone particles of size 30 mm down to size of above 72-mesh size.

Cyclones The limestone particles of size 72 mesh from the ball mills are sent into a cyclone which stirs the slurry at a high speed of about 130 m3/hr. The fine particles remain at the top and are then sent to the storage tanks, while the heavier particles sink down are re fed into the ball mill.
Agitated storage tanks
These tanks with 2000 m3 of storage keep mixing the slurry mixture to avoid the particles settling on the bottom of the tank before they are transported to the cement manufacturing plant.
Vacuum filter
This filter is used to separate water and limestone particles from the slurry. The separated limestone particles are sent to the drier to be dried and the water is sent to the clarifier to be reused later. The capacities of the filters are 65 m3/hr.

Drier In this process limestone particles are dried in a kiln by passing hot gas through it. The dried limestone particles are then sent to the cement manufacturing plant while the hot gases are released to the atmosphere via the stacks after passing them through the electrostatic precipitator. Dries has a capacity of 115 t/h.

Q9) Alternative Systems

Alternative System | Suitability | Aerial Ropeway | Despite aerial ropeway being a great option for this sort of projects (mountain areas) the distance between the two plants is too big for this option to be considered. About 400 towers are needed to handle this volume of material. | Road and Rail | Both of these options are not real options due to the tract between the two plants is hilly and rugged terrain, plenty of landslides are experienced in the past and a lot of deforesting would be involved, so it will be so expensive or next to impossible to build road or rail tracks. | | |

References:

http://www.poandpo.com/s1112/linde_material_handling.jpg http://i.ytimg.com/vi/LfGUjiMhXI4/hqdefault.jpg http://www.majorwire.cc/main/sites/default/files/proven-solutions/Casey_0.JPG http://i00.i.aliimg.com/img/pb/110/660/295/295660110_855.jpg. http://www.usinenouvelle.com/industry/img/mineral-processing-impact-hammer-mills-000127451-4.jpg

http://modularmachines.co.in/uploads/images/20140910190625_7500.jpg http://modularmachines.co.in/products/ore-dressing-equipment/Ball_Mill_31.html http://exaircorp.files.wordpress.com/2013/09/cyclone.gif
https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcT6h14l3KExmsOaCvpFOZbwYH_DNql62NsoYsK6fqpR6WEVKc64Gg