Gasoline blending in tanker

shvet,

What do you mean by "gasoline components"? and "blending"

If this is small amounts then a simple injection skid can be used, but its not clear to me whether this is some sort of ship based mixing of products to generate a blended product ( risk of incomplete mixing) or what exactly?

tankers normally allow you to pump products from one tank to the other or blend or mix at your will.

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Let me explain a bit

"Gasoline components" mean blending stocks: C4, naphtha, isomerizate, alkylate, oxygenates etc.
"Blending" means we mix stocks and produce a fuel in specs.
This is not a small amount like a metal-based octane booster is. Most stocks are 1-10% v/v, so a simple injection skid is not applicable.

We have negative experience with on-board mixing. A tanker does have some compartments for components but it is not designed for blending so we obtained blends not in specs / not as was intended. We have positive experience in blending onshore. The question is do we have option to provide precise dosing / blending on board?

On line blending is perfectly feasible, but needs to have on line measurement of whatever your key issue is.

You probably need to use inline mixers, but is best to go via a storage tank of some sort to pick up any variances in quality before delivery to the customer.

You will need a skid with control valves and fast acting control equipment and instruments which can respond quickly to changes in the thing they are measuring. No reason at all why you can't fit that somewhere on the ship upstream of the discharge manifold.

The risk is that if some parameter changes or one of the mixing fluid runs out or stops pumping then you are delivering off spec product. Unless you can catch it in time before delivery your risk is how to dispose of off spec product?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

Thank you, but this is not exactly what I am looking for.

It is difficult to ensure adequate mixing is accomplished without being forced by one mechanical means or another. It is also possible that incompletely mixed components reseparate just due to density differences in a short amount of time. Additives are always injected into the stream as the tankers discharge their loads, never into their tanks themselves.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

Though this ship board blending is out of the ordinary, dont see why this cannot be made to work. What you can do onshore at the tank farm, you can also do on a ship's deck. A lot depends on the reliability of the onboard octane analyser.

On the other hand, if you can establish onshore, a blending recipe for a given set of feedstreams, it is only a matter of maintaining this same blending ratio by means of accurate flow ratio control at the ship board blending skid - no need for the inline octane analyser to be on the ship's blending controls skid.

Thanks, gentlemen

Again - the isuue concerns blending stocks, not additives or specs correcting.

georgeverghese said:

On the other hand, if you can establish onshore, a blending recipe for a given set of feedstreams, it is only a matter of maintaining this same blending ratio by means of accurate flow ratio control at the ship board blending skid - no need for the inline octane analyser to be on the ship's blending controls skid.

Click to expand...

We are looking for options/vendors for such packaged equipment that is practiced being installed on a tanker deck or similar.

This document says on board blending of different cargoes to make new blends is not permitted, for ships registered in flag states operating in the IMO-SOLAS jurisdiction I presume, during sea voyages for reasons listed in the document. The scope of this prohibition is also extended to inter cargo blending whilst a ship may be moored at a port in some cases. What exactly then, is the scope of the operation of this blending skid you plan to source - is it to be operated only when a ship is moored, and that this skid is not for intercargo blending?

Options will depend on whether you are based and what the local manufacturing capacity is.

These will be custom designed and built so first find yourself a design company.

It is a pretty simple skid to design and build.

I don't know enough about in line octane analysers but the designer will.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

After discounting the obvious quality and safety issues, it is solely regulatory matters that apparently prohibit this practice. Looks like its going to be a stick build if you intend to do it.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

Thank ou, gentlemen

1/ Is blending prohibited or not, it is only question of the amount of a surcharge.

2/ It is obvious that any modification is possible if the proper engineering efforts had been applied. If one wants a tanker is able to be redesigned to FPSO. All of you suggest some sort of modification requiring redesign/reengineering of a vessel. While I am looking for a widely practiced option, a device/unit being able to be purchased&installed&connected with minor modifications only.

#1 To the unscrupulous, it is so. We just tend to not give advice that is contrary to law, code and/or safety practice.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."