Description
The Punta de Piedra wood chip mill and export facilities is designed for producing and exporting 1 million metric tons per year of caribbean pine wood chips. The complex receives logs by truck fm local plantations, processes the logs into chips, and stores and conveys the chips via network of belt conveyors to the dock where the chips are loaded into ocean-going vessels.
The dock is located on the northern bank of the orinoco river, at mile 167 fm orinoco seabuoy, near to punta piedra, abt 20 miles downstream fm pto.ordaz.
General description of the dock
the dock consists of two (2) breasting dolphins, each of which support a slewing, luffing, and (2) telescoping ship loaders, a central support tower which supports a belt conveyor transfer and control tower, five (5) mooring buoys, and a conveyor belt/walkway bridge which connects the landside conveyor belt system with the dock central tower.
Each breasting dolphin consists of four steel pipe piles (2.238 m o.d.) Connected by a 13 meter wide by 16 meter long by 2 meter deep reinforced concrete pile cap. This concrete deck structure is the main operating and equipment support platform at elevation +13.3 m.
The two breasting dolphins are arranged in the east-west direction, 87 metrs apart, and in a water depth which allows docking of vessels of up to 54.000 dwt capacity throughout the year.
A stationary slewing/luffing/telescoping ship loader is supported on a steel tower over each breasting dolphin.
The south (riverside) face of each breasting dolphin is protected with a fender system designed for berthing woodchip carrier vessels up to 54.000 dwt in full ballast condition.
Each fender system consists of:
1. Two rubber fenders, one supported on the pile cap at elevation +12.3 m and other supported on the two front piles through a steel beam at elevation +5.5 m.
2. A 2,36 m x 9,5 m steel fender panel, which spans over and is supported by the two rubber fenders. This panel is covered with uhmw polyethylene sheets to reduce friction and provide protection to the ship's hull.
The central support tower consists of four steel piles (2,00 m o.d.) Connected by a 10,8 meter wide by 16 m long by 1,75 meter deep reinforced concrete pile cap. This tower, located at the midpoint between the two breasting dolphins, supports the conveyor transfer tower with control cabin, and serves as a storage platform for trimming equipment.
A conveyor with walkway bridge connects the central transfer tower to the landside conveyor system. This bridge is supported by two pile bents spaced at approximately 53 m. Each pile bent consists of two steel piles (2,00 m o.d.) With a 2,80 m wide by 1,75 m meter deep reinforced concrete pile cap. The conveyor and walkway support trusses span between structural steel bents anchored to the concrete pile caps.
A five-buoy mooring system is used to secure the vessel in position during berthing and loading operations.
Tubular truss walkways connect each of the breasting dolphins to the central support tower at elevation +13.3 m. A rotating ramp provides access fm the central support tower deck at elevation +13.3 m to a floating boat landing pontoon attached to the back (landside) of the downstream breasting dolphin.
Design criteria
annual river level fluctuations.
Highest high water (hhw) +11,6 m (refered to m.s.l.)
Lowest low water (llw) +0,30 m (refered to m.s.l.)
L.l.w. (@ aramaya water level recorder) = 0,3 m + m.s.l.
Wood chip carrier particulars used for port design/calculations:
"mv forestal esperanza" (maximum size)
Dwt 53.680
l.o.a. 228.4 m
beam 32.2 m
mld. Depth 22.5 m
draft (summer) 11.0 m
draft (ballasted) 6.85 m
"mv ionian prince" (minimum size)
Dwt 31.905
l.o.a. 196 m
beam 29.7 m
mld.depth 20.8 m
draft (summer) 9.7 m
draft (ballasted) 7.0 m (assumed)
Minimum water depth required along dock 13,70 m
Determined as follows:
Max.size wood chip carrier forestal esperanza
summer draft 11,00 m
draft variation (9") 0,23 m
tropical draft 11,23 m
tropical fresh water darft 11,55 m
vertical ship movement due to wave, trim
and atmospheric pressure 0,35 m
net underkeel clearence 1,20 m
sounding accuracy 0,60 m
total 13,70 m
Berthing criteria
Breasting dolphin are designed for the flwg criteria:
Design vessel 53.680 dwt wood ship carrier (full ballasted)
approach velocity 0,14 m/sec (5.5 in/sec) normal to berth
max.approach angle 8 deg.
Max.fender/hull pressure 15 ton/m2
dist. Between breasting dolphins: 87 m
Mooring buoy system
A five-buoy mooring system is used to secure the vessel in position during berthing and loading operations. Two buoys are located to the bow of the ship, one to each side of its axis. Two buoys are located between the ship and river bank. The remaining buoy is located rowards the stern of the ship at an angle of approximately 45 deg. With respect to its longitudinal axis. Design horizontal pull each buoy is 100 tons.
Each mooring buoy consists of:
" a cylindrical buoy (10 ft diameter x 4,5 ft deep)
" a 200 ton quick release hook
" mooring chain (100 ton cap.)
" a 4 ton concrete sinker
" anchorage to bottom/shore:
buoy no.1 is connected to two (2) ship anchors, while the remainder of the buoys are anchored directly to rock near or at shoreline.
The mooring lines are designed for a 54.000 dwt wood chip carrier:
" in ballast condition subject to a 40 mph lateral wind force.
" in ballast condition subject to 40 mph longuitudinal wind force and 4
knot current parallel to the berthing line.
" in loaded condition subject to a 45 mph longitudinal wind force and 4
" knot current parallel to the berthing line.
Ship loader information
The two ship loaders are fixed base, slewing, luffing, telescoping
boom units, manufactured by bmh, designed for independent loading of
wood chips into dedicated wood chip carriers. Vessel up to 228 m in lenght
can be fully loaded in one position. No ship shifting will be required to
accomplish complete loading of all vessel holds. At river water
elevations +9.0 m and higher, vessel may require ballasting.
Each ship loader is independently operated. The operator uses a radio control remote operator's panel to control the movement of the ship loader. The ship loaders may also be controlled fm the mcc/control room located in the central transfer tower.
The ship loaders are designed so that they can be shifted fm the stowed position (boom tip pinned to the central tower) to the ship loading position during high water conditions for the range of ships specified.
After positioning the ship loader over the selected hatch the operator can adjust the slewing angle, incline of the boom, and shuttle position to start loading of the hold. The ship loader is fitted with a telecopic spout and high speed belt trimmer which allows for loading of chips to the outer dimensions of the ship hold. By rotating the ship trimmer the operator can distribute chips in 360 deg. Arc from the telescopic spout.
The ship loaders are designed to lift and position a caterpillar d4c track-type tractor (weight not exceed 16,400 lbs). The telescopic chute which is used to raise and lower the tractor. When the tractor is being lifted, the trimmer must be removed fm telescopic chute.
Design ship dimensions
dwt (min-max) 32,000 - 54,000
lenght overall (loa) 196 - 228 m
ship's beam 29,4 - 32,2 m
molded depth 20,8 - 22,4 m
ballasted draft 4,0 - 6,5 m
Material specifications
product handled wood chips
bulk density 22-25 pcf
particle size maximum 3"
angle of repose 42-46 deg.
Moisture by weight 43-47 % nominal
Ship loader data
design loading capacity 1,135 mtph @ 24 pcf
discharge point - boom extended 160' (48,75 m) fm pivot
discharge point - boom retracted 94'-4" (28,75 m) fm pivot
boom lenght overall 211'-7" (64,47 m) extended
operating slewing arc +/-65 deg.(fm perpendicular axis to ship)
slewing speed 30 deg/minute
operating luffing angle +/- 15 deg.
Luffing speed 10 deg/minute
maximum luffing angle +38 deg.
Minimum luffing angle -15 deg.
Shuttling speed +/- 20 fpm
Wind restrictions
each ship loader is designed based on the following criteria of wind speed.
Operating condition: each ship loader is designed for continuos operation at winds up to 50 mph.
Storm condition: each ship loader must be pinned and tied down in a cradle, located on the transfer tower for winds above 50 mph.
Pls find below some graphs abt wood chips installations which we believe will facilitate the understanding of this new project. |
