2x100% Simplex Filter v/s 1x100% Duplex Filter 1

[Chemitofreak]

Hi,

Can anybody cite the advantages and disadvantages (barring cost factor) of using 2x100% Simplex Filter v/s 1x100% Duplex Filter.

Should the Process Engineer define it, or should it be left to the vendor to decide.

Thanks in advance.

Dinesh S SHELATKAR.
Process Engineer

 

[EmmanuelTop]

Provided that both arrangements meet the same isolation philosophy/requirements, it all boils down to the same thing. You end up with 2 units designed for 100% throughput.

Dejan IVANOVIC
Process Engineer, MSChE

 

[Chemitofreak]

Dejan,

Thanks a lot for a prompt reply.

I also know that the two units will end up for 100% throughput, but while specifying in the Process Datasheet what shall be specified 2x100% Simplex Filter or 1x100% Duplex Filter. Is there any criteria for concluding what shall be specified i.e. line size, flowrate etc. or shall we leave it to the vendor to take a call on the same.

Thanks once again.





Dinesh S SHELATKAR.
Process Engineer

 

[LittleInch]

Advantages - less space and less valves and piping

~Disadvantages - those 2 three way valves on the unit need to seal very well and hot swapping on line will result in some debris on the upstream side in contact with the valve plug. In theory they are good, but you would need to ask operations how they find them after a few years of operation. Generally only for low pressure applications.

Never leave options like this to a vendor.

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

 

[EmmanuelTop]

The only thing that comes to my mind - apart from what I wrote in my previous post - is configuration of the inlet/outlet and auxiliary piping. If the entire piping has been designed for a single point of connection (i.e. single inlet, single outlet, single drain etc.), this normally calls for a Duplex package where all internal piping connections are in the vendor scope. However, this is all so easily convertible into 2x100% standalone configuration with addition of a few tees.

Plot space requirements are usually less for Duplex units, so limited footprint can be a reason for specifying a Duplex arrangement.

Dejan IVANOVIC
Process Engineer, MSChE

 

[Latexman]

2x100% Simplex is more robust and safer in my experience.

1x100% Duplex has smaller footprint, less valves, less capital cost.

Good luck,
Latexman

Technically, the glass is always full - 1/2 air and 1/2 water.

 

[bimr]

The question is how much downtown is acceptable when you have to stop operating to clean a filter. That is the key consideration.

 

[LittleInch]

In either case it should be none, that's why it's 2 x 1005 or a 100% duplex filter. The problem comes if the 3 way valve passes and whe it's integral, it takes longer to fix than swapping out or blinding a valve on the 2 x 100% option.

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

 

[bimr]

The post is somewhat general. Some filters need to be cleaned every shift, other filter applications maybe only once per year. The cleaning cycle may be a consideration.

However, for maintenance purposes, you would want the filters to be independently operated should something need to be repaired.

A general recommendation is 2x100% Simplex will be more robust and reliable. Agree with Latexman.

 

[Latexman]

Thanks bimr. Since 2x100% Simplex are separate, it's easier to fix problems than on a Siamese twin duplex (they share too many working parts and are too close/tight).

Good luck,
Latexman

Technically, the glass is always full - 1/2 air and 1/2 water.

 

[EmmanuelTop]

Duplex arrangements do not necessarily come with a 3-way valve, however the point made by LittleInch is spot on - this should be examined and approved/rejected on a case to case basis. I have also seen 3-way valve arrangement with 2x100% configuration so it is ultimately with the designer to specify the required valving and isolation facilities.

I would also say that 2x100% configuration works better if more frequent changeovers of filter media is required. Accessibility can be an issue with Duplex filters.

Dejan IVANOVIC
Process Engineer, MSChE

 

[georgeverghese]

As suggested, check if any inbuilt isolation valves meet the project or plant owner maintenance isolation requirements - you may need drop out pipe spools and the like before quick closure disassembly is permitted. If pressures are very high, have come across some plant operators who will not run these changeout operations even when good double block and bleed valves are included on these units.

 

[Chemitofreak]

I would like to summarise what is been discussed over here

2x100% Simplex Filters
• Robust and safer
• Easy accessibility and maintenance
• High Cost
• High floor print

1x100% Duplex Filters
• Low Cost
• Low floor print
• Not so robust and safer as filters are integrated into a common casting/forging
• Not convenient in terms of easy of accessibility and maintenance

The final selection between the two shall be based on the filter changeover time, convenience of the operator and the points aforementioned.

For maintenance purposes, one would want the filters to be independently operated should something needs to be repaired. A general recommendation is 2x100% Simplex.


Dinesh S SHELATKAR.
Process Engineer