7 replies to this topic

[lakshmi.narayanan]

Dear members,

 

We are currently into developing a tools for 98.5% concentrated H2SO4 tank sludge cleaning. In case of MS/SS304/SS316, it seems the materials are resistance to acid sludge to some extent. But they are highly reactive to dilute acids. While cleaning with water, the diluted acid corrodes the metal surface. Hence cleaning of tools becomes problem. 

 

Request you to kindly guide us in selection of proper Metal MOC for the tool. Is there any option available for metal quoted with Teflon/ any other material.

 

Also please guide us in the after cleaning procedure to avoid corrosion. Can we use caustic/Lime solution for cleaning followed by water washing.

 

Regards

Lakshmi narayanan

 

[Pilesar]

Review this sulfuric acid manual for materials of construction and other suggestions:  https://files.engine...lfuric_Acid.pdf

[breizh]

Hi,

Corrosion data from a reputable source.

Breizh

Attached Files

•  Sandvik H2SO4 Corrosion Data.xlsx   217.7KB   20 downloads

[shvet1]

I had been working on a process facility where concentrated H2SO4 was extensively used. We practiced cleaning process equipment (including storage vessels) with weak caustic and subsequent water washing. We used rubber chemical-resistant hoses, self-made simple SS nozzles and similar with no a negative feedback for ~50 years.

 

As for me the critical issue is the layout of system so way to provide total draining (no liquid pockets). The rest issues are minor.

 

Curious to know why you need a special tool for such purposes. Please explain.

Edited by shvet1, 04 January 2024 - 11:45 AM.

[lakshmi.narayanan]

I had been working on a process facility where concentrated H2SO4 was extensively used. We practiced cleaning process equipment (including storage vessels) with weak caustic and subsequent water washing. We used rubber chemical-resistant hoses, self-made simple SS nozzles and similar with no a negative feedback for ~50 years.

 

As for me the critical issue is the layout of system so way to provide total draining (no liquid pockets). The rest issues are minor.

 

Curious to know why you need a special tool for such purposes. Please explain.

 

Dear Shvet1,

 

Thanks for your reply.

 

We are into design of a cleaning robot for removing sludge in H2SO4 (98%) storage tank. Aim is to achieve No man entry while cleaning. The robot will eliminate the risk of manpower engaged in tank cleaning.

We need guidance on the selection of MOC of the robot. Hence shared the query in forum.

As per your reply, it seems we can go with SS316 for robot body with chemical resistance rubber shoes. Is there any theoretical reference for material selection for 98% H2SO4 @ 40 degC. 

 

Also can you please explain us more on the procedure of cleaning H2SO4 storage tank with weak caustic followed by water washing. Our worry in particular is diluted H2SO4 is very much reactive to SS/MS material. How this can be eliminated while caustic cleaning/water washing. 

[lakshmi.narayanan]

Hi,

Corrosion data from a reputable source.

Breizh

Dear Breizh.

 

Thanks for your reply. The data seems to very useful for our purpose.

[lakshmi.narayanan]

Review this sulfuric acid manual for materials of construction and other suggestions:  https://files.engine...lfuric_Acid.pdf

Dear Pilesar,

 

Thanks for sharing the article. 

[shvet1]

This is improper forum for such issues. 

In general - any acid-resistant coating is ok for such environment. In specific - glass, enamel, gold, tantalum and hardwood are the only materials proven for such environment.

 

I recommend start with coated cast-iron & carbon steel (furan-, epoxy-, vinylester-based) and halogenated polymers (HBR, PVC, PTFE, PVDF).

 

Do not reply, no humor.

Are you sure there is a place at this planet where the cost of labour is so high to justiffy investment in mech-robots during a such simple and occasional procedure like tank cleaning? There seems no profits other than reputation as bio-robots renting is the most convenient and competitive. 

Edited by shvet1, 11 January 2024 - 12:15 AM.