Chemical cleaning procedure 3

[ivu]

Dear all,

I'm looking for a chemical cleaning procedure for carbon steel pipes. The aim is cleaning some new lines upstream a recip compressor.
I will really appreciate any information (guidelines, acid/neutralizing solutions,...).
Thanks in advance
IVU

 

[jonralph]

I work for a company involved in Pre-Commissioning of plant. We do chemical cleaning, both the normal Acid pickling and the more modern one step and neutral processes. I can email or fax you some guidelines. Whats your intention? Guidelines for review of a subcontractor, information for a bid or are you intending to do this yourself?

Email me at jralph@pslg.com

 

[ivu]

As this is a small conventional pickling job to be performed, we would like to do it ourselves.
I'm interested in as much information as possible: fluid summary, solution compositions, soaking times, fluid velocities for each stage, filtering system...
As it is available onsite, we are thinking on using citric acid.

 

[butelja]

We have used citric acid for cleaning pipes and storage tanks (liquid service) with excellent results. I'm not sure what the concentration was. One thing to be careful of is that the cleaned steel is activated and more succeptable to corrosion imediately after cleaning. If ppm levels of iron could contaminate your product, then this could be a problem.

 

[imtiyaz]

hello ivu!!
i am not a expert in this field but i could get something for you from a friend. hope you will find it useful.
precaution is metal other than steel should not come in contact with pickling solution and all valves gaskets, CV etc should be dropped before chemical cleaning.
the procedure is the method of cleaning & passivation of internal surface of CS piping based on use of inhibited HCL acid followed by passivation with sodium hexametaphosphate, prior to taking in service.

seq. of operation;
a0 flushing with water to remove dirt etc.
b0 degreasing
c0 inhibited acid circulation
d0 neutralisation with soda ash / caustic soda.
e0 rinsing
f0 passivation
g0 drying

Concentration of HCL should be 5-10% by wt. HCl (on 100% purity basis) and Rodine-213 special (corrossion inhibitor)should be added in acid solution in prop of i lit. Rodine 213 special to 100 lit 30-33% HCl. however exact conc. and acid solution to be decided on visual inspection of CS piping.

there are other steps to follow. if i am in right track for your question please reply. so that i can send down the balance part of the procedure.

 

[ivu]

Imtiyaz,
This is the information I needed, and matches with the procedures I'm using as a basis.
At this moment I'm checking the Citric acid concentration needed to give a solution similar to this 7-10% HCl you are talking about.
In any case I'd really appreciate any further information you could send to me: ivu@bilbao.com
thank you very much indeed. IVU

 

[imtiyaz]

hello ivu!
it's great to know that my answer(information) to your query on eng-tips.com corrossion forum was of some help to you. i have emailed you the complete detail and posting it here for our other forum friends. do let me know about your sucess with citric acid.

now starting from where i left;
chemicals required are;
1) caustic soda-rayon grade or technical grade.
2) HCL acid commercial/technical grade
3) corrosion inhibitor (in india rodine-213 is generaly used)
4) glassy sodium meta-phosphate (sodium hexametaphosphate.
5) soda ash technical grade
6) potable water
NOTE :test of inhibitor efficiency and effectiveness of the solution in removing mill scale.
cleaning procedure:
1) general precaution & testing of loop to be done. flushing is recommended.
2) filling & circulation of sodium hydroxide sol for 2 hrs (minimum).
3) temp. of sod. hydoxide sol. during circulation between 65-75 deg Centigrade.
4) concentration of sod hydroxide should be 50 gm/lit(on 100% purity basis)
5) drain sod hydroxide sol. clean with water till pH of water at inlet & outlet ends are same.
6) fill and circulate inbited HCL solution for 6 hrs (minimum).
7) temp. of the sol between 50-60 deg C.
8) Concentration of HCL should be 5-10% by wt. HCl (on 100% purity basis) and Rodine-213 special (corrossion inhibitor)should be added in acid solution in prop of i lit. Rodine 213 special to 100 lit 30-33% HCl. however exact conc. and acid solution to be decided on visual inspection of CS piping.
9)drain the sol. fill with 1-2% sol. of soda ash or caustic soda and circulate for 1 hr at 40-50 deg C.
10) drain the neutralising sol. clear with water till pH of water at inlet & outlet is same.
11)fill and circulate sod. hexametaphosphate sol for 2-4 hrs.
12) conc of the sod. hexametaphosphate sol should be 2-3% by wt (on 67% P2O5 basis) with pH adjusted to 5.50-6.50. and temp while circulating 70-75 deg C.
note: to prevent reoxidation, passive sol to be introduced immediately.
13) drain passive sol (remember)without flushing with water.
14) dry the circuit with dry air.
NOTE: #these operation in any loop when commenced must be completed without interruptions.
#also whenever acid is added the corrosion inhibitor should be added first.
#acid strength, total iron and ferric iron to be determined every hour during operation.
#during passivation presence of phosphate to be checked periodically.

best of luck and take care.
imtiyaz

 

[john52]

DEAR SIR.
I CAN GIVE YOU ANY INFORMATION YOU WANT FOR CHEMICAL CLEANING PROJECTS.
OUR COMPANY IS DEALING SINCE MANY YEARS BEFORE IN THIS BUSINESS.
OUR FIELD IS THE MARINE,OILFIELD AND POWER STATIONS INDUSTRY.
OUR TERRITORY IS ALMOST WORLD WIDE.WE PROVIDE EITHER FULL PACKAGE CONTRACT SERVICES OR SIMPLY CONSULTANCE SERVICES.
IN CASE YOU ARE INTERESTED PLEASE CONTACT US.
RGRDS
JOHN PITSILOS/ DIRECTOR
jpc@jpchemicalnet.gr

http://www.jpchemicalnet.gr

 

hi all,,

that discussion was very useful,,,

i would ask a basic question ,,,

why we need to clean carbon steel new pipes ..? is it because of some particles left after manufacturing of pipes ?

is this needed for seamless pipes ?

is there another alternative of chem cleaning ? like sandblasting ?