Static mixer

[xnabrar]

Hi All.

As per P&ID we required Static Mixer but the supplier asks me the below questions.

1. What is the objective of the mixer, what are you trying to achieve?
2. Will the customer accept a smaller diameter mixer to ensure good mixing? It looks like the mixer is unnecessarily large for the flowrate that is going through it.
3. What is the maximum allowable pressure drop that can occur across the mixer?

the required document I attached, anyone tells me what I reply to supplier?

 

[georgeverghese]

Q1. Ask the process licensor.
Q2. Indeed, for <900bpd, this 36inch line appears to be grossly oversized.
Q3. Choose a dp that is say not more than 20% of the pressure drop permitted at the downstream PCV.

It is strange why the process licensor wants a static mixer here, when there is good shear mixing at the downstream PCV. Why not get rid of the SM, and shift the AIT to downstream of the PCV, provided the fluid remains single phase liquid downstream of the PCV. What dp is allocated to the PCV?

Looks like the piping drafting team in your office have completely hijacked these P&I Ds'.

 

[1503-44]

Sometimes shear mixing should be avoided, such as when using drag reducing agents, but then the control valve is there anyway.
Yeah, no way it is for 900. Maybe it is for 900,000 BOPD

I would expect you should answer with something like this.

1. What is the objective of the mixer, what are you trying to achieve?
That's pretty obvious. It's a mixer, but I imagine you might perfer to answer this with...

Uniformly mixed oil/water/vapor emmulsion at the indicated process conditions and as may be further described in the attached specifications, documents and drawings attached to this inquiry.

2. Will the customer accept a smaller diameter mixer to ensure good mixing? It looks like the mixer is unnecessarily large for the flowrate that is going through it.
The Bidder is instructed to submit his primary quotation strictly as per the requirements of the specifications, documents and drawings attached to this inquiry.

The Bidder may, in addition to his primary quotation, propose an alternative design that meets all the requirements of the attached specifications, documents and drawings included within this inquiry with certain exceptions proposed by Bidder. Any and all deviations from and exceptions to such requirements shall be specifically and clearly noted by Bidder in writing. Any alternate design so proposed by Bidder shall be submitted to CLIENT at no additional cost to CLIENT and only with the full understanding that CLIENT accepts no obligation of any kind, expressed or implied, to consider any such proposed alternate quotation, exceptions, or designs contained therein, in whole or part, should he choose not to do so. The Bidder shall include any and all appropriate supporting calculations and design documentation as may be necessary to prove the technical aspects and advantages of his proposed alternative design to the complete satisfaction of CLIENT.

3. What is the maximum allowable pressure drop that can occur across the mixer?
The maximum pressure drop across the mixer shall not exceed the greater of that required to ensure complete conformance with tbe attached specifications, documents and drawings, or that pressure drop needed to guarantee acceptable performance of the mixer when operated under the specified conditions.

“What I told you was true ... from a certain point of view.” - Obi-Wan Kenobi, "Return of the Jedi"

 

[xnabrar]

dear,
1. georgeverghese
2. ax1e

thanks for the valuable response.

 

[LittleInch]

We can't tell based on this snap shot.

The line is 36" but the data sheet say 42".

Flows unless they mean kbbls/day are crazy low.

It looks to be a mixer to emulsify the water in the oil, but why? - god knows but we don't as we don't know what is coming in and where it fits init the grand scheme of things

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

 

[xnabrar]

LittleInch

 

[Latexman]

Ask the old, gray haired guys there.

Good Luck,
Latexman
Pats' Pub's Proprietor

 

[LittleInch]

Why are you responsible for buying something you clearly know nothing about??

That snapshot doesn't help I'm afraid. Nothing makes sense here. It even says MAOP 610 psi but max operating on the table is 850!

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

 

[mk3223]

It seems that a "mixing efficiency" missed in the static mixer specification.

One experience to share...The mixer element type and sizing could be different as the efficiency changed from 95% to 99%.

 

[xnabrar]

LittleInch

Now we are on the bidding stage, As per SOW, we have to consider the Static mixer.
So it is necessary to understand the equipment operation and other factors.

 

[LittleInch]

If this is not properly described in the bid documents then send in a technical qeury to the client.

There is no point guessing and putting in something which is the wrong item

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

 

[georgeverghese]

As part of bid clarification, you may be permitted to ask why the design calls for a static mixer when there is a PCV downstream that does the same thing - talk to the proposals manager.

 

[xnabrar]

LittleInch
georgeverghese

thanks

 

[xnabrar]

Dear
again vendor query

We need some more clarifications:
- Is the application homogenisation before crude oil sampling? and if so are they are using ISO 3171 as their basis for representative sampling and if yes are they aiming for c1/c2 >0.9 or something else?
- Designing a static mixer that gives homogeneity and c1/c2>0.9 from zero flow to maximum flow as indicated on the datasheets is not possible. If this is the case then we can not quote for this process, only a powdered jet mixer system can provide this solution.
- If the minimum flow is not zero and you would like to have c1/c2>0.9 then we will likely have to make the diameter smaller for all mixers, considering the flowrates given.
- Also we require the pressure drop so we have some constraints to work with

 

[SandCounter]

Maybe drawing BA-528728, sheet 2, rev. 6 will give a clue.