Chemical cleaning is the process of technologically treating the inwalls of pipes according to specific craftmanship by adding a few inhibitors or acid/alkali solution mixed with active agent. Pickling pipes is to get rid of oxidazing materials or oil stains through pickling pipes with the effect of brightened surface and required cleanliness. There are two ways to pickle pipes: tank pickling and cycling pickling.

General provisions of Pickling pipes 

a.Pickling should be adopted when derust hydraulic and lubricating pipes.

b. Pickle pipes should be after fixing the pipes and the flushing conditions prepared.

c.While pickling, measures of anti-acid-corrosion  should be taken to the screws  and  seals of the pipes;no metal gasket in the pipes while pickling.

d. Remove paint completely before pickling painted pipes.

e.The density of the pickling solution and the proportion of defferent composition according to the corrosion degree and the quality the water.

f.The water used must be clean and the content of chloridion contained should be more than 25ppm for stainless steel pipes;make sure the compressed air used to spray anti-rust oil after pickling dry and clean.

g. Time needed for pickling is depent on the corrosion condition, the density and temperature of acid solution.

1. Pickling in tanks

a.Procedures:degease→flush→pickle→flush→neutralize→passivate→flush→dry→spray anti-rust oil→seal

b.Exhaust the air of curled pipes before putting them in the pickling solution.

c.Put smaller pipes upside when put them in the pickling tank.

2. Cycle pickling

a. Procedures: test leakage→degease→flush→pickling→flush→neutralize→passivate→flush→dry→spray anti-rust oil→seal.

b.The length of sodium loops is depent on the pipes and should be shorter than 300m.

c.A release should be set on the toppest part of the sodium loop pipes and a valve on the lowest
part.

d. Add neutralization solution thrugh pickling loops till the solution come out of the outlet is not acidic.

Standards after pickling:

a.No adhered substance on the inwalls of the pipes after pickling.

b.The inwalls should be greyish white or greyish black.