unloading system

[uu78hswang]

Dear Sir/Madam

Layout A/B are two different types of unloading system.
Could you please help me out to find out what theese two systems's advantange and disadvatange?
Note. In layout B, (a),(b), ( c) are different ports of truck delivery load to storage tank,
And it seems b, c is perferable but I don't the reason behind
Could you please help me out also.

Thank you so much.

 

[jesspo]

Well in layout A, you have a Flow element on a recyle loop so you cannot tell how much your actually taking out of the tank. there is also no way to feed material into the tank, so i doubt it's viable at all.

In layout B The flow element is in the right spot, so the storage system is at least viable.
(a)you could get into trouble since the truck stream is intersecting with the tank stream, so you can't really tell how much you're putting in the tank. And if you have to shut the tank off, there's possibility of pump cavitation.
(b) is the best option because you'd bet suction action from the pump, with no possibility of feeding directly to the process.
(c) is only gravity fed so if your truck isn't in an ideal location it wouldn't empty all the way into the tank.

 

[uu78hswang]

Dear Jesspo
In layout B, location (a) is easy in since the pump suction pressure might be low enough to suck the raw material out of
the truck into the system. However there are many unseen risks being taken. First, many bulk deliveries are
made by applying pressure load of N2 or compressed air to the top of the delivery vehicle. If the
tank operator is not monitoring the unloading, there is a distinct chance that the compressed gas
could blow through when the vehicle is empty. This may cause the pump to cavitate.

But, I am not quite sure you mention (a)shut the tank off, there's possibility of pump cavitation. Could you explain clearly?

thank you so much.

 

[dcasto]

neither are very good at all. The closests is A. As pointed out above, you do not need a flow element on the recycle, you need it on the to proces line. Then you need a flow control valve on the discharge of the pump. You only need a recycle if you believe the pump could go into surge. If the pump is small energy user, just put a fixed RO on the recycle at a min flow size. If it is a larger pump, the recycle needs a control valve of its own.

If the pump is huge, put a VFD on it.

 

[someguy79]

Follow dcasto's advice for this.

Also, it's not clear how you plan to offload from your supply truck to the ISO/raw material storage tank.

Is this a gravity feed from the truck or a pump line? Different valving and other equipment will be needed depending on your offloading mode.

Also, there will be complications for flammables, combustables, cryogenics, high viscosities, toxics, and various other fluid characteristics. I just mention this stuff because it's not clear what you intend to do with this system.