Dear James,

I do have experience in loading 40.000 dwt ships with cement (In Roterdam and Antwerp).

Both with pneumatic unloaders and fixed, shore based pneumatic conveying installations from silos to the ship.

The principle of pneumatic loading vessels is the reverse of pneumatic unloading vessels.

2 times 300 tons/hr medium sized second hand cement unloaders are capable of doing the job.

The vessel has to be treated as a silo.

The biggest issue is the removal and cleaning of the convey air from the ship's hold and the prevention of over- and under pressure in the ship's hold.

There are ways to cover this issue.

Then, there have to be flanged openings in the hatches of the ship to accommodate trimming devices and de-aeration connections to a shore based filter.

If the flanges in the hatches are not available, then they can be cut and welded and repaired afterwards. (Done before).

To each loading point on the hatches a pipe of 10” or 12” (depending of the unloader size) has to be mounted, connected with flexible hoses.

All this requires the use of a crane (Could be ship’s gear) and the input of man labor.

The pneumatic unit is stationed at one location, close to the silo and the hatches are reached by pipes.

Shifting a 40000 dwt ship is not preferred and most of the time there is not enough quay length available.

The actual layout of the operation is very much depending on the local situation.

It is absolutely necessary that the whole operation is managed by a well informed and experienced supervisor, who is aware of the functioning and possible risks of over pressure in a ship's hold.

At least leave the hatches loose from the coaming (not latched) and maintain some under pressure in the hold.

I know of an occasion where, against the instructions, someone caused a hatch lifting and damaging the structure.

Using a number of bulk trucks is probably a cheaper operation, however, the issues of maintaining under pressure in the hold and cleaning the convey air as well as the loading flanges are the same.

Such big ships are probably not normal sea going ships, as they require more holds to comply with the leak stability rules.

What kind of ships are they, lakers?

Have a nice day

Teus ■

Hi James,

The issue of de-aerating the holds and cleaning the holds air seems to be taken care of.

Using airslides requires elevation above the hatch level of a 40000 dwt ship + loading bellow.

From the pictures, there is no possibility to move the ship, requiring air slides along the whole length of the cargo area of the ship (approx. 150 m) with several loading points.

Assuming an airslide angle of 6 degr. over a distance of 150 m requires alone 150*tan(6) = 16 m of height.

Plus the level of the empty ship of approx 12m, makes 28 m.

Each dropping point (every 15m # 10 dropping points) from the air slides uses approx 1 m, adding another 10m, totaling to 38m.

This 38 m can be divided in 2 or 3 elevators.

All this equipment must be knitted in in the existing structure.

A pneumatic conveying pipe can be routed much easier in an existing structure.

The existing loading tower can be used for airslide loading to the ship. A screw would be too heavy probably.

The silos are converted from grain to, I presume, fly ash.

The existing transportation equipment is most likely not suitable for fly ash, due to the flow ability property differences.

Is the load out equipment from the silos also coverted?

The pneumatic (un)loaders could be positioned near the silos and the fly ash be blown to the loading tower that is modified for the loading of fly ash instead of grain.

The converted loading tower can easily be connected to the pipe connections, spread over the main conveying pipe.

My suggestion of bulk trucks might not be so good, due to the lack of space on the jetty and not a sufficient number of loading stations.

Is the annual throughput enough to justify such investments for big ships? May be smaller and therefore more ships are more economic, but that would destroy the investment in the over 40000 dwt silo storage.

40000 tons of fly ash is a huge amount.

A self discharging bulk carrier for fly ash can only be a dedicated ship, a pneumatic self discharger or with a mechanical unloading system with screws. Both will have fluidized bottoms and very important, filters for the de-aeration of the holds.

A lot of those self dischargers, suited for for cement and fly ash, can be loaded and unloaded pneumatically very easily and they are widely available on the freight market.

If the fly ash is used for cement production, a pneumatic self unloader vessel is preferred, as the silos at the cement production plants are almost always equiped with pneumatic conveying loading pipes.

Or they must buy a pneumatic unlader, which is for a 40000 dwt ship a rather big machine.

It seems that a number of arrangements have to be considered and evaluated, until the most feasible solution emerges.

Have a nice day

Teus ■

Hi James,

I understand the reasoning behind the project.

I presume that the ships are loaded with cement at another site, otherwise you could use the same installation.

A similar installation as on the cement loading site cannot be used?

A sole loading port on the ship is a feature of every, self unloading, cement/fly ash carrier

The only option I see for your project, is making various preliminary designs and evaluate them.

One of them would be using the adapted, existing traveling loading tower.

Success

Teus ■

cement transport

Originally Posted by r.j.morrish

href="showthread.php?p=67298#post67298" rel="nofollow">

Hi Teus

The main plan is to convey pne. from the converted grain silos to the ship. Flex connection to the ships holds - some ships will require on shop rigid pipes.

To cover all cases,....we will provide a shore based dust collector - with flex. ducting from ships holds to the unit. This system has been used by us at other silos/ports....dedicated cement/ash

The exist wharf does not have a lot of clearway due to grain loader/galleries - so I am looking to mount shore based dust collecotr off grain shiploader plus a hose handling crane.

My question is over an alternative system - using air slides to transfer fly ash to the wharf. Using airslides 100% is not neat/easy due to different holds plus 40k DWT ship is 12m above wharf at mean spring.

Hence, a bit of a hybrid situation - airslides to wharf side loader. Then mobile loader to ships holds.....this is my area of interest

I do not know what a lake vessell is...we deal with up to 40k DWT - 4 holds - powder handling or bulk materials self discharger

Attached are images of the wharf.

Thanks

James

Hello and good afternoon Teus and Mr Morrish,

A Laker sized vessel is a long narow ore carrier used to transport iron ore, stone, cement, coal, grain to the Great Lakes of the United States and Canada.

The lakers sized ships are long and relatively narrow in cross section from port to starboard with a very shallow draft to maintain the ability to transition through the Welland Canal, Soo Locks and the Saint Lawrence Seaway to the inland ports along the routes.

I wonder if the Wallinga ship loader- unloader would be of help with the smaller volumes?

These units are on wheeled carrriers and have swivel booms to allow the boom to swing to the middle of the holds of lakers for example to suction out the loads and also discharge them.

Attachments

shipunloader_brochure_jmb (PDF)

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