Overhead Pulley for Heat Exchanger Bundle pulling

[starfarooq]

We have a vertical exchanger (called waste heat boiler)installed at our ammonia plant. Often we have to replace the tube bundle for which we use 150 tons crane (the bundle weight is 50 tons). Now we want to install overhead pulley over the exchanger so that we have permanent arrangement for the tube bundle pulling. Can anybody advise whether pulleys with such capacity are available in the market and is this option financially viable?

 

[berkshire]

I think what you are looking for is more correctly called a hoist not a pulley, try googling hoists.
B.E.

The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor

 

[dhengr]

Starfarooq:
There are a number of systems and means or equipment for doing this operation, and it could likely be a dedicated system, but if you already have a crane, why the new system? And, at what cost? You have to think of a number of things here: lifting capacity, you must already have most of the rigging equipment you need; how does this system move and on what structure, during lift out of the tube bundle and final lay down, or pick-up of the new bundle; what is this new lifting system supported on, and what is its own structural system? The existing crane and operator do all of these things and your new system must duplicate them at a lower cap’y.

 

[MintJulep]

So you put a pulley or a hoist over the exchanger and you lift the tube bundle out.

What next?

You need to be able to move the now removed bundle horizontally to do anything useful.

Jib crane or gantry crane might be what you are looking for.

http://www.spanco.com/products/jib-cranes/

or many other vendors.

 

[racookpe1978]

1) A 150 ton crane rental is $$$$$.$$ per hour - plus a lot of more dollars and time for setup and removal. So, the logic makes sense.

2) Height of the new hoist, run length of the rails to the laydown area, and let-down area "length" (because you are going to lay the tube bundle down changing from vertical to horizontal), and the horizontal component of forces as you lay it down need to be considered by your structural design group for the gantry/rail system.

That is, your new crane needs to be able to lift the tube bundle up clear of the HX, move sideways, then lower the bundle to ground level for removal, then either fix the bottom of the bundle and let the top move sideways as it lowers, or fix the top of the bundle and "pull" the bottom out sideways as it lays over onto the removal truck or chassis.

 

[rmw]

Nice job Mr Cook.

Starfaroog,

It depends too on how often you have to pull this bundle. While as racookpe mentions, the rental on a large crane is expensive, once it is packed up and gone, you have no more expense. Any crane you install you will have to then maintain and have inspected from time to time.

You need to get ahold of a couple of suppliers of this type of equipment and have them come to your plant and see if they have anything to offer that might meet your need. Even if they don't they may be able to refer you to someone else in the business who can.

rmw

 

[Nivrah]

Starfaroog,
you have a number of options there. As rmw pointed out, you have to work out if the installation of a crane is the better cost effective way than hiring a crane. Also, you might want to explore the pay back period if you install a crane.

If you do go for the installing a crane:
Try Kone cranes...we have a lot of them around our site and given that they are one of the key players in the crane world, you can expect good technical advice and support.

P.S: your SWL for the crane has to be 110% (Australia codes) of the working load.See your codes for lifting devices.