Stockyard layout (re)design

Transcription

1 Delft University of Technology Faculty 3ME, Transport Engineering & Logistics G. Lodewijks, T.A. van Vianen and J.A. Ottjes Delft University of Technology Challenge the future 1

2 Export Terminal Saldanha Bay SA 2 2

3 Bulk terminal simulation 3

4 Content 1. Stockyard functions 2. Stockyard machines 3. The machine selection for capacity & blending or homogenizing 4. The machine selection for the storage of bulk materials 5. CASE: stockyard layout design for an import terminal 6. Summary Delwaidedok, Antwerp (Courtesy HeliHolland/Kees Vlot) 4

5 1. Stockyard functions 5

6 Stockyard functions 6

7 2. Stockyard machines 7

8 Stockyard machines - Overview (1) Handling coal using wheel loaders and mobile feed bunker (Courtesy N.M. Heilig BV) Stacking of coal using a stacker (Courtesy ThyssenKrupp) Circular storage (Courtesy HeliHolland/ Kees Vlot) 8

9 Stockyard machines - Overview (2) Bucket wheel reclaimer (Courtesy FAM) Bucket wheel stacker/reclaimer, left: stacking, right: reclaiming (Courtesy ThyssenKrupp) 9

10 Stockyard machines - Overview (3) Double sided bridge scraper reclaimer (Courtesy ThyssenKrupp) Reclaiming with a side scraper and stacking with an overhead belt conveyor (Courtesy Taim Weser) 10

11 3. The machine selection for capacity & blending or homogenizing 11

12 Stockyard machines - Effective capacity ratio (1) During terminal (re)design, the effective capacity ratio is essential to prevent selecting a machine with insufficient capacity Effective capacity ratio for a bucket wheel reclaimer relates to the used reclaiming method Long-travel reclaiming method Slewing bench reclaiming method 12

13 A s (θ) θ max ω s θ (A) Δx M M A s (θ) Δr p ω r Δx (B) h s h Slewing reclaiming method A) top view and B) lateral view 13

14 Nominal reclaiming capacity, without slewing speed adjustment: cos( ) C h x l r r s ss b bw m Nominal reclaiming capacity, with slewing speed adjustment: C h x l r r s ss b bw m Parameter Description Value Unit Parameter Description Value Unit h s Slice height 4.5 [m] r bw Radius of bucket wheel 4.5 [m] Δx Max. chip thickness 1 [m] ω ss Minimum slewing speed [rad/min] ρ m Bulk density coal 0.8 [t/m 3 ] ω sm Maximum slewing speed 0.58 [rad/min] l b Boom length 60 [m] a s Maximum slewing acceleration/ deceleration 0.5 [rad/min 2 ] 14

15 Reclaiming capacity for the slewing bench reclaiming method relates to (i) slice cross-sectional area, (ii) the slewing speed and (iii) bulk density of the reclaimed material. The reclaim capacity can be kept stable with an increase of the slewing speed Cr ωs Cr ωs 0.4 Cr [kt/h] ωs [rad/min] Cr [kt/h] ωs [rad/min] θ [ ] θ [ ] Without slewing speed adjustment With slewing speed adjustment 15

16 Stockyard machines - Effective capacity ratio (2) The effective capacity ratio was calculated for bucket wheel reclaimers for the long-travel and the slewing-bench reclaiming method. Parameter Description Value Unit Parameter Description Value Unit l t Total pile s length 325 [m] h Slice height 4.5 [m] w Pile s width 50 [m] Δx Maximum chip thickness 1 [m] h Height of the pile 18 [m] l b Boom length 60 [m] ρ m Bulk density coal 0.8 [t/m 3 ] r bw Radius of bucket wheel 4.5 [m] α Angle of repose 38 [ ] ω ss Start slewing speed 0.25 [rad/min] v t Travelling speed 10 [m/min] ω sm Maximum slewing speed 0.58 [rad/min] a t Travel acceleration and deceleration 0.15 [m/min 2 ] a s Maximum slewing acceleration & deceleration 0.5 [rad/min 2 ] y Distance centerline machine to pile 10 [m] 16

17 The effective capacity ratio was for the long-travel reclaiming method 75% and for the slewing bench reclaiming method 45% Note: these ratios are not general but were derived using specific input parameters Cr [kt/h] long travel slewing bench Time [min] Reclaiming capacity during a time interval of 40 hours for two reclaiming methods 17

18 C r [kt/h] l t [m] Reclaiming efficiency versus the pile's length for the long-travel reclaiming method 18

19 Stockyard machines Main Characteristics Machine type Maximum capacity [t/h] Effective capacity ratio [ ] Stockpile width [m] Reclaiming method to the pile Stacker 10, Radial stacker 8, Ø120 Side scraper 1, Alongside reclaimer Single boom portal 2, Alongside scraper reclaimer Double boom portal 4, Alongside scraper reclaimer Bridge scraper 1, At the face reclaimer Bridge bucket wheel 10, At the face reclaimer Drum reclaimer 4, At the face Bucket wheel reclaimer 12, Alongside 19

20 Blending or homogenizing machines Stacking is the starting point of the blending process. Generally there are four basic stacking methods in out Reclaimer machine Single scraper reclaimer and Portal scraper reclaimer Stacking method Cone Shell Chevron Strata Windrow Bridge scraper reclaimer Bridge bucket wheel reclaimer Drum reclaimer Bucket wheel reclaimer

21 4. The machine selection for the storage of bulk materials Selection of archetype Cost calculation Operational performance 21

22 Selection of archetype Multi-purpose machine (stacker/reclaimer) or two single-purpose machines (stacker and reclaimer) ṁ in A ṁ out (I) (A) ṁ in B1 ṁ out (II) B2 (B) Stacker/reclaimer Stacker Reclaimer Incoming stream Outgoing stream Belt conveyor Stockyard lane Two layout archetypes 22

23 Cost calculation Selection must be based on the archetype s investment cost and performance It was assumed that the machine investment cost relates to its weight and the belt conveyor investment cost relates to its capacity 1,200 1,000 lb=25±3 [m] lb=30±3 [m] lb=37±3 [m] Upper limit Lower limit Quotations: 1 Lbc 1.5 [km] w [t] lb=46±1 [m] lb=63±3 [m] κbc [k /m] C s + C r [t/h] C bc [kt/h] Stacker/reclaimers weight versus capacities as function of boom length Price per meter for belt conveyors versus its transport capacity 23

24 Operational performance The performance at dry bulk terminals is generally expressed in the total time that ships and trains spend in the port The port time is the sum of the waiting time and service time The ships waiting time relates to: Interarrival time distribution Carrier tonnage distribution The ship (un)loader utilization Mean service rate Mean arrival rate Queuing theory formulas or simulation 24

25 5. Case: stockyard layout design for an import terminal 25

26 Main requirements: Import terminal with an annual throughput of 37 [Mt/y], 21% bypass (no storage and handling by stockyard machines) Required stockyard area: 92 [ha] Seaside: bulk carriers, landside: trains Interarrival time distribution seaside and landside: NED Carrier tonnage distribution: based on historical data (avg. 101 [kt]) Train tonnage distribution : uniform distributed between 2 and 4 [kt] Stockyard machine efficiency: 0.55 [-] 4 unloaders at seaside and 4 loaders at landside Average seaside s port time (W ss ): 3 days and average landside s port time (W ls ): 0.5 day Blending of coal: 1.7 [Mt/y] 28 different grades of bulk materials must be stored separately 26

27 Step 1: Determine the number of stockyard lanes (n l ) and dimension the stockyard lanes (length L l and width w). Assume a machine s boom length (l b ) of 60 meter and use 10 meter as distance from the machine s centerline to the stockyard lane (p). Assume that the lane s length (L l ) must be in the range between 1,000 and 1,500 meter Number of stockyard lanes must be an even number to realize complete archetypes. Calculate the number of archetypes using the following equation: A n l L l l b p An outcome is n l = 14, L l = 1,315 [m] and w = 50 [m] 27

28 Step 2: Determine the required machine capacity based on W ss 3 days and W ls 0.5 day for both archetypes. 1,315 [m] Layout A with 7x archetype (I) S1 A B S2 C E R1 D F 1,315 [m] S3 G I R2 H J A C E G I K M SR1 SR2 SR3 SR4 B D F H J L N S4 S5 S6 K M O Q S U R3 R4 R5 L N P R T V O Q SR5 P R S7 W Y R6 X Z S U SR6 T V AA R7 BB W Y SR7 X Z Stacker Bulk carrier AA Stacker/reclaimer Stockyard lane (un)loader Bulk carrier Train Yard conveyor BB Reclaimer Train Stockyard lane Yard conveyor (un)loader Layout B with 7x archetype (II) 28

29 Step 2: results of the simulation study Wss [d] Wls [d] (A) Layout A: 7x archetype (I) Layout B: 7x archetype (II) C s [kt/h] (B) Layout Machine C s [kt/h] C r [kt/h] A Stacker/Reclaimer B Stacker 3.6 Reclaimer Layout A: 7x archetype (I) Layout B: 7x archetype (II) C r [kt/h] 29

30 Step 3: Calculate the total investment cost per archetype. Calculate the stockyard machine s weight (w) based on the determined stacking and reclaiming capacities Investment cost of the stockyard machine(s): ICsm w sm where for this case it was assumed that κ sm was 8 [ /kg], machine fully installed at the stockyard Investment cost for the belt conveyor(s): IC bc L bc where L bc is conveyor length (1,400 [m]) and κ bc was according Figure slide 22 upper limit. Layout Machine C s [kt/h] C r [kt/h] w [kt] IC sm [M ] IC bc [M ] TIC (A) [M ] bc A Stacker/Reclaimer B Stacker Reclaimer

31 Step 4: Design the blending bed with associated machine types. Future: high-quality coal will probably become scarce thus install stacker and reclaimer combination which is able to realize the highest bed blending ratio Blending bed dimensions: assume coal-fired power plant s own storage of 5 days and use two blending beds for simultaneously stacking and reclaiming. 31

32 Step 5: Final layout. 1,315 [m] A C E G I K M O Q S U W Y AA SR1 SR2 SR3 SR4 SR5 SR6 SR7 B D F H J L N P R T V X Z BB Stacker/reclaimer Stockyard lane Bulk carrier Train (un)loader Stacker Yard conveyor Double sided bridge scraper reclaimer 32

33 6. Summary 33

34 Summary Three main stockyard functions: storage, blending and homogenizing Main characteristics of stockyard machines were presented The effective capacity ratio for bucket wheel reclaimers differs per reclaiming method; a method has been provided. Different combinations of stacking methods and reclaimers result in specific bed blending effect ratios. A selection procedure was introduced to select single-purpose or multi-purpose machines for the storage of bulk materials For a specific case, the stockyard layout was designed Future work: Design of the network of belt conveyors 34

35 Questions? 35