4 replies to this topic

[Charu]

I have to blanket a vessel carrying refined palm oil for the manufacture of margarine with nitrogen.

The pressure inside the vessel is maintained at 1.2 atm. The blanketing is necessary only during the weekend. After the start up, after the week end, it is necessary to add ingrediants to this vessel through a manhole. But if we open the manhole, the operator will face the hazard by exposing himself to too much nitrogen. What modification can be done?? There is a pressure relief valve, and a vacuum breaker installed and a nitrogen vent to vent the nitrogen till the pressure inside the vessel reaches 1 atm.

[breizh]

Hi ,
To me not much , you have all the hardware in place . Make sure that the operator stops the N2 prior to vent the vessel to atmosphere and before opening the manhole . You need to write a standard operating procedure ( SOP) + train your teams
Hope these helps
Breizh

[riven]

Don't know much about palm oil but the most important question is why do you blanket in the first place (which is probably obvious to those familiar with palm oil)?

If it is to prevent explosive atmosphere then opening the manhole is not a possibility: Use a pump to add your ingredients and adjust the nitrogen pressure accordingly.
If it for product protection/degradation prevention then a short opening of the manhole will cause little problem - follow Breizh advice.

Remember to ensure that the operator may also be exposed to palm oil vapors which may be an issue?

[Art Montemayor]

Charu:

Both Breizh and Riven’s responses are not specific to your query because you fail to furnish specific, detailed basic data. I also have to guess and make assumptions (which may or may not apply):

• I took the time to edit your original post to make it more readable and understandable. You fail to space between sentences and you don’t use Spell Check – if you lack English vocabulary knowledge.
• You give The pressure inside the vessel as maintained at 1.2 atm, but you fail to state if this is operating, or another pressure state. I presume that you are venting the vessel while it is at 1.2 atm, since you fail to say what is the pressure at which you vent to add ingredients.
• You fail to state that the ingredients added are either liquid or solid. This is a BIG issue.
• If this is Palm Oil used as raw material for local margarine production, I assume that you nitrogen blanket in order to protect the Palm Oil from oxidation from the ambient air and cause a raw material off-spec, and impurity in the final margarine product.

As Riven suggests, if the ingredients are liquids, than a pump is called for and this is a straight-forward process that does not require any nitrogen venting (& blanket wastage).

If, however, the ingredients are solids the issue becomes one of having to gain a sizable access to manually add the solids. But even this scenario is subject to a modification that allows you to maintain the nitrogen blanket and not have to go through the time and nitrogen expense of venting procedures. Please refer to the attached Excel Workbook where I show a modification that I have used in the past for batch reactors in which solid catalysts or ingredients have had to be added while the reactor is under pressure. This may be what you need to save time, nitrogen, and maintain a safe operation.

Attached Files

•  Solids additon to Pressurized Vessels.xls   25.5KB   75 downloads

[fallah]

Charu:

Both Breizh and Riven’s responses are not specific to your query because you fail to furnish specific, detailed basic data. I also have to guess and make assumptions (which may or may not apply):

• I took the time to edit your original post to make it more readable and understandable. You fail to space between sentences and you don’t use Spell Check – if you lack English vocabulary knowledge.
• You give The pressure inside the vessel as maintained at 1.2 atm, but you fail to state if this is operating, or another pressure state. I presume that you are venting the vessel while it is at 1.2 atm, since you fail to say what is the pressure at which you vent to add ingredients.
• You fail to state that the ingredients added are either liquid or solid. This is a BIG issue.
• If this is Palm Oil used as raw material for local margarine production, I assume that you nitrogen blanket in order to protect the Palm Oil from oxidation from the ambient air and cause a raw material off-spec, and impurity in the final margarine product.

As Riven suggests, if the ingredients are liquids, than a pump is called for and this is a straight-forward process that does not require any nitrogen venting (& blanket wastage).

If, however, the ingredients are solids the issue becomes one of having to gain a sizable access to manually add the solids. But even this scenario is subject to a modification that allows you to maintain the nitrogen blanket and not have to go through the time and nitrogen expense of venting procedures. Please refer to the attached Excel Workbook where I show a modification that I have used in the past for batch reactors in which solid catalysts or ingredients have had to be added while the reactor is under pressure. This may be what you need to save time, nitrogen, and maintain a safe operation.

Dear Art,

Appreciate for your attractive solid addition configuration.My minor comments:

1-Vent valve to be rated for MAWP of vessel
2-Added solid should be in powder form
3-In some cases (smaller valve size,agglomeration of powder,....) it may need to shaking facilities e.g. putting an expantion joint (rated for MAWP of the vessel) between hopper and ball valve and shaking the hopper
4-In the case of moderate/high pressure in the vessel,for emptying the hopper,it may need to pressurizing the hopper by a separate line through the vent valve on the hopper (or by taking-off a pressure equalization line from top of the vessel and connect to vent valve)
Please correct if it needs to correction

Edited by fallah, 01 June 2010 - 03:00 AM.