Chemical Cleaning
Content
CHEMICAL
CLEANING
GENERAL GUIDELINE AND PROCEDURE
PREPARED BY:
Industrial Cleaning Services Public Company Limited
Office address:
88/8 Warisara 3 Moo 3 Pala , Ban Chang, Rayong 21130, Thailand
CHEMICAL CLEANING
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Ref. No. :
Issued Date: 017/06/ 2014
Rev. 0
Page: 2
Work shop address:
99 Moo 3, Pala District, Ban chang, Rayong 21130, Thailand
Phone: 038 601029 Fax. 038 601030
SECTION 1
STAINLESS STEEL CHEMICAL CLEANING
INTRODUCTION
This procedure covers the chemical cleaning (pickling) of the stainless
piping either prior to fabrication commissioning or post operational
maintenance
purpose
by
chemical
circulation
method.
The
present
specification covers the pickling and passivation of SS piping and does not
require separate passivation of pickled surface.
The object of the chemical cleaning is to remove all extraneous matter,
dirt, dust, grease, oil, welding slag, loose rust, oxide scales that may be
present on the piping to avoid the contamination of the production mainly by
way of iron pick up. The chemical cleaning is required to achieve product
quality. This procedure specifies the method of cleaning and passivation of
internal surfaces of SS piping based on use of acid mixture of nitric acid and
hydrofluoric acid prior to taking in service for the first time after installation
or fabrication.
WORKING PROCEDURE
STEP 01 - WATER FLUSHING & LEAK TEST:
The circuit (loop) shall be checked with circulation of water to check
tightness. Any leakage if observed shall be attended and tightened.
a) Fill up water to Tank
b) Start water circulation : Water Tank => Pump => Piping system
=> Water Tank
CHEMICAL CLEANING
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Ref. No. :
Issued Date: 017/06/ 2014
Rev. 0
Page: 3
c) Stop water circulation if line have not leak and ready to use
chemical circulation
STEP 02 - ALKALINE CLEANING
The purpose of alkaline cleaning is to remove dust, dirt, oil, grease and
other organic matter inside the piping system.
Chemical Cleaning Agent :
a. ICS 008 Surfactant 0.2 – 0.5% vol
b. NaOH 0.5%
Reaction Phenomenon:
Hydrocarbon + ICS 008 [R(OC2H4)nOH]
CxHy + R(OC2H4)nOH R(OC2H4)n.CxHy + H2O :
Hydrocarbon removal
a) Circulate degreaser chemical (Sodium Hydroxide 1-2% + ICS 008
surfactant 0.2-0.4%) in order to remove fat, grease, welding slag,
and other dirt inside the pipe.
b) Regularly check the turbidity content every 10 minutes,
c) Stop the circulation if the turbidity content show stable value at
least 3 times. Estimated time for this step is 1 hour.
3.1 Drain the alkaline solution, and then fill with fresh water and circulate.
This operation of rinsing with water should be continued till pH of water
at the inlet and outlet ends are same.
3.2 Circulate acid cleaner chemical (HNO3 5% + H2SO4 1%) in order to
remove remaining iron contamination and mild scale inside the pipe.
Regularly check the turbidity and iron content every 15 minutes, stop
CHEMICAL CLEANING
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Ref. No. :
Issued Date: 017/06/ 2014
Rev. 0
Page: 4
the circulation if the iron content show stable value at least 3 times.
Estimated time for this step is 2 hour.
3.3 Drain the acid solution, and then fill with fresh water and circulate. This
operation of rinsing with water should be continued till pH of water at
the inlet and outlet ends are same. (notes: the acid waste should be
neutralized prior to disposal)
3.4 Finally, dry the circuit by passing clean dry instrument air.
NOTES:
1. The above pickling procedure includes passivation and does not require separate passivation of pickled
surface.
2. The chemically cleaned and dried piping shall not be taken into operation within 72 hours after the final drying
operation is completed.
Flowchart of Chemical Cleaning
CHEMICAL CLEANING
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Ref. No. :
Issued Date: 017/06/ 2014
Rev. 0
Page: 5
CHEMICAL CLEANING
Ref. No. :
Issued Date: 017/06/ 2014
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Rev. 0
Page: 6
SECTION 2
CARBON STEEL CHEMICAL CLEANING
INTRODUCTION
This procedure covers the chemical cleaning (pickling) of the carbon
steel piping or tubing either prior to fabrication commissioning or post
operational maintenance purpose by chemical circulation method.
The object of chemical cleaning of post operational piping systems is to
remove oil, grease and other organic matter, and mostly include corrosion
products, mineral scale, sludge, or process contaminants, in any
combination.
The result of this cleaning is that the metal surfaces are completely
clean, dry and in the passive state without signs of corrosion. The chemical
cleaning of the steam generators consist of the following:
WORKING PROCEDURE
STEP 01 - WATER FLUSHING & LEAK TEST:
a. Fill up water to Tank
b. Start water circulation : Water Tank => Pump => Piping system =>
Water Tank
c. Stop water circulation if line have not leak and ready to use
chemical circulation
STEP 02 - ALKALINE CLEANING
The purpose of alkaline cleaning is to remove dust, dirt, oil, grease and
other organic matter inside the piping system.
CHEMICAL CLEANING
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Ref. No. :
Issued Date: 017/06/ 2014
Rev. 0
Page: 7
Operating condition :
a. Pressure
: Atmospheric
b. Temperature
: If possible, conveniently piping system
water temperature should be kept from 70°C to 90°C
Chemical Cleaning Agent :
a. ICS 008 Surfactant 0.2 – 0.5% vol
b. NaOH 0.5%
Reaction Phenomenon:
Hydrocarbon + ICS 008 [R(OC2H4)nOH]
CxHy + R(OC2H4)nOH R(OC2H4)n.CxHy + H2O
:
Hydrocarbon removal
Procedure :
a. Inject ICS 008 from chemical mixing tank.
b. Heat-up piping system water to approximately 70°C to 90°C
c. Check water analysis (Turbidity) every hour.
d. Stop alkali cleaning if turbidity analysis show stable trend.
e. Fill up new water in the system and circulate until water clear
STEP 03 - ACID CLEANING
The main purposes of the acid cleaning are removal of mill scale and
iron oxide that deposited inside the tube piping system during
operational period.
Ref. No. :
CHEMICAL CLEANING
Issued Date: 017/06/ 2014
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Rev. 0
Page: 8
Operating condition :
a. Pressure
: Atmospheric
b. Temperature
: If possible, conveniently piping system
water temperature should be kept from 50°C to 70°C
Chemical Cleaning Agent :
a. HCL 5 – 10% vol. solution
b. ICS 02C (acid inhibitor) 1 : 100 of HCL 32%
Reaction Phenomenon:
6HCl + Fe2O3 2FeCl3 + 3H2O
: Rust removal
2HCl + CaCO3 CaCl2 + H2O + CO2
:
Calcium
scale
removal
MgCO3 + 2HCL MgCl2 + CO2 + H2O
:
Magnesium
scale removal
Procedure :
a.
Fill up water into piping system system
b.
Flushed water until water clear
c.
Dose ICS 02C (acid inhibitor) as acid inhibitor in order to
prevent some corrosion on metal surface from acid.
d.
Slowly dose HCL into circulating tank to dilute with water
and then feed into piping system system by using pump
and keep circulate
e.
Maintain pH < 3 during circulation.
f.
Carry on circulation the chemical solution for 6 – 8 hr
CHEMICAL CLEANING
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
g.
Ref. No. :
Issued Date: 017/06/ 2014
Rev. 0
Page: 9
Check water analysis (Fe2+, Turbidity) every 2 hour. If
Fe2+ or turbidity tendency stable at least 2 sample then
drain all solution
h.
Drain to ditch after neutralization until pH = 6 - 8
STEP 04 – NEUTRALIZATION AND PH CONTROL
Operating condition :
o Pressure
: Atmospheric
o Temperature
: Ambient
Chemical Cleaning Agent :
o NaOH – control pH until 8-9
Procedure :
a. Add the NaOH to the system gradually until the pH raise to
9 – 9.5, but not exceed 10 before entering passivation step
b. Maintain the circulation for at least 1 hour to ensure the pH
9 – 9.5 of the system have uniformly established.
STEP 05 - PASSIVATION
The neutralizing treatment is carried out to stabilize the metallic
surfaces of a system after acid cleaning and for preventing the
corrosion until the system start-up. Especially, the rust prevention of
carbon steel requires sufficient cares because the surface becomes
very active after the acid cleaning.
Chemical :
CHEMICAL CLEANING
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Ref. No. :
Issued Date: 017/06/ 2014
Rev. 0
Page: 10
o Hydrazine 0.05%
o NaOH – control pH 9 – 9.5
Reaction Phenomenon:
N2H4 + 6Fe2O3 4Fe3O4 + 2H2O + N2
agent
N2H4 + O2 2H2O + N2
:
Passivizing
: Oxygen scavenger
Procedure :
a.
Fill up water in the system and circulate
b.
Dose of Sodium hydroxide 50% to the circulation tank
slowly.
c.
Circulate until pH of water circulation is more than 9 then
stop dose NaOH.
d.
Dose of hydrazine to chemical mixing tank and start
circulate
e.
Carry on Circulate for about 4 -8 Hours
f.
Drain the water solution and passivation finished.
STEP 06 – DRYING
a.
Finally, dry the system by blowing with nitrogen
b.
Check oxygen content inside the tube regularly
c.
Stop the nitrogen blowing after oxygen content reaches
<0.5%, hold the nitrogen inside with pressure 0.5 barg.
CHEMICAL CLEANING
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Ref. No. :
Issued Date: 017/06/ 2014
Rev. 0
Page: 11
Figure 1. Flowchart of carbon steel chemical cleaning
Table 1. Job quality plan of carbon steel chemical cleaning
N
o
Process
Chemical used
Condition
Control
Measuring
End point
criteria
Remark
CHEMICAL CLEANING
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Temp
1
2
Leak test
Alkaline
cleaning
Demin water
ICS 008 0.2%
ambie
nt
ambie
nt
Time
(hou
r)
8
NaOH 0.5%
3
Acid Pickling
HCL 5-10%
inhibitor 1 : 100
HCL
Item
pH
12
pH
any time
every
hour
every
hour
Turbidity
Iron
content
4
Neutralization
NaOH
5
Passivation
Hydrazine 0.05%
6
Dry
plant air
1.
FLOW DIAGRAM
ambie
nt
ambie
nt
ambie
nt
2
pH
12
pH
12
Nitrogen
Issued Date: 017/06/ 2014
Rev. 0
Page: 12
Frequen
cy
Turbidity
ambie
nt
Ref. No. :
every
hour
every
hour
every
hour
No leakage
pH 10-14
Turbidity stable
at least 2 time
add more
chemical if
pH decrease
pH 1-2
Turbidity stable
at least 2 time
Iron contect
stable at least
2 time
add more
chemical if
pH increase
pH 9-10
pH 9-10
O2 content <
0.5%
CLEANING
GENERAL GUIDELINE AND PROCEDURE
PREPARED BY:
Industrial Cleaning Services Public Company Limited
Office address:
88/8 Warisara 3 Moo 3 Pala , Ban Chang, Rayong 21130, Thailand
CHEMICAL CLEANING
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Ref. No. :
Issued Date: 017/06/ 2014
Rev. 0
Page: 2
Work shop address:
99 Moo 3, Pala District, Ban chang, Rayong 21130, Thailand
Phone: 038 601029 Fax. 038 601030
SECTION 1
STAINLESS STEEL CHEMICAL CLEANING
INTRODUCTION
This procedure covers the chemical cleaning (pickling) of the stainless
piping either prior to fabrication commissioning or post operational
maintenance
purpose
by
chemical
circulation
method.
The
present
specification covers the pickling and passivation of SS piping and does not
require separate passivation of pickled surface.
The object of the chemical cleaning is to remove all extraneous matter,
dirt, dust, grease, oil, welding slag, loose rust, oxide scales that may be
present on the piping to avoid the contamination of the production mainly by
way of iron pick up. The chemical cleaning is required to achieve product
quality. This procedure specifies the method of cleaning and passivation of
internal surfaces of SS piping based on use of acid mixture of nitric acid and
hydrofluoric acid prior to taking in service for the first time after installation
or fabrication.
WORKING PROCEDURE
STEP 01 - WATER FLUSHING & LEAK TEST:
The circuit (loop) shall be checked with circulation of water to check
tightness. Any leakage if observed shall be attended and tightened.
a) Fill up water to Tank
b) Start water circulation : Water Tank => Pump => Piping system
=> Water Tank
CHEMICAL CLEANING
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Ref. No. :
Issued Date: 017/06/ 2014
Rev. 0
Page: 3
c) Stop water circulation if line have not leak and ready to use
chemical circulation
STEP 02 - ALKALINE CLEANING
The purpose of alkaline cleaning is to remove dust, dirt, oil, grease and
other organic matter inside the piping system.
Chemical Cleaning Agent :
a. ICS 008 Surfactant 0.2 – 0.5% vol
b. NaOH 0.5%
Reaction Phenomenon:
Hydrocarbon + ICS 008 [R(OC2H4)nOH]
CxHy + R(OC2H4)nOH R(OC2H4)n.CxHy + H2O :
Hydrocarbon removal
a) Circulate degreaser chemical (Sodium Hydroxide 1-2% + ICS 008
surfactant 0.2-0.4%) in order to remove fat, grease, welding slag,
and other dirt inside the pipe.
b) Regularly check the turbidity content every 10 minutes,
c) Stop the circulation if the turbidity content show stable value at
least 3 times. Estimated time for this step is 1 hour.
3.1 Drain the alkaline solution, and then fill with fresh water and circulate.
This operation of rinsing with water should be continued till pH of water
at the inlet and outlet ends are same.
3.2 Circulate acid cleaner chemical (HNO3 5% + H2SO4 1%) in order to
remove remaining iron contamination and mild scale inside the pipe.
Regularly check the turbidity and iron content every 15 minutes, stop
CHEMICAL CLEANING
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Ref. No. :
Issued Date: 017/06/ 2014
Rev. 0
Page: 4
the circulation if the iron content show stable value at least 3 times.
Estimated time for this step is 2 hour.
3.3 Drain the acid solution, and then fill with fresh water and circulate. This
operation of rinsing with water should be continued till pH of water at
the inlet and outlet ends are same. (notes: the acid waste should be
neutralized prior to disposal)
3.4 Finally, dry the circuit by passing clean dry instrument air.
NOTES:
1. The above pickling procedure includes passivation and does not require separate passivation of pickled
surface.
2. The chemically cleaned and dried piping shall not be taken into operation within 72 hours after the final drying
operation is completed.
Flowchart of Chemical Cleaning
CHEMICAL CLEANING
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Ref. No. :
Issued Date: 017/06/ 2014
Rev. 0
Page: 5
CHEMICAL CLEANING
Ref. No. :
Issued Date: 017/06/ 2014
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Rev. 0
Page: 6
SECTION 2
CARBON STEEL CHEMICAL CLEANING
INTRODUCTION
This procedure covers the chemical cleaning (pickling) of the carbon
steel piping or tubing either prior to fabrication commissioning or post
operational maintenance purpose by chemical circulation method.
The object of chemical cleaning of post operational piping systems is to
remove oil, grease and other organic matter, and mostly include corrosion
products, mineral scale, sludge, or process contaminants, in any
combination.
The result of this cleaning is that the metal surfaces are completely
clean, dry and in the passive state without signs of corrosion. The chemical
cleaning of the steam generators consist of the following:
WORKING PROCEDURE
STEP 01 - WATER FLUSHING & LEAK TEST:
a. Fill up water to Tank
b. Start water circulation : Water Tank => Pump => Piping system =>
Water Tank
c. Stop water circulation if line have not leak and ready to use
chemical circulation
STEP 02 - ALKALINE CLEANING
The purpose of alkaline cleaning is to remove dust, dirt, oil, grease and
other organic matter inside the piping system.
CHEMICAL CLEANING
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Ref. No. :
Issued Date: 017/06/ 2014
Rev. 0
Page: 7
Operating condition :
a. Pressure
: Atmospheric
b. Temperature
: If possible, conveniently piping system
water temperature should be kept from 70°C to 90°C
Chemical Cleaning Agent :
a. ICS 008 Surfactant 0.2 – 0.5% vol
b. NaOH 0.5%
Reaction Phenomenon:
Hydrocarbon + ICS 008 [R(OC2H4)nOH]
CxHy + R(OC2H4)nOH R(OC2H4)n.CxHy + H2O
:
Hydrocarbon removal
Procedure :
a. Inject ICS 008 from chemical mixing tank.
b. Heat-up piping system water to approximately 70°C to 90°C
c. Check water analysis (Turbidity) every hour.
d. Stop alkali cleaning if turbidity analysis show stable trend.
e. Fill up new water in the system and circulate until water clear
STEP 03 - ACID CLEANING
The main purposes of the acid cleaning are removal of mill scale and
iron oxide that deposited inside the tube piping system during
operational period.
Ref. No. :
CHEMICAL CLEANING
Issued Date: 017/06/ 2014
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Rev. 0
Page: 8
Operating condition :
a. Pressure
: Atmospheric
b. Temperature
: If possible, conveniently piping system
water temperature should be kept from 50°C to 70°C
Chemical Cleaning Agent :
a. HCL 5 – 10% vol. solution
b. ICS 02C (acid inhibitor) 1 : 100 of HCL 32%
Reaction Phenomenon:
6HCl + Fe2O3 2FeCl3 + 3H2O
: Rust removal
2HCl + CaCO3 CaCl2 + H2O + CO2
:
Calcium
scale
removal
MgCO3 + 2HCL MgCl2 + CO2 + H2O
:
Magnesium
scale removal
Procedure :
a.
Fill up water into piping system system
b.
Flushed water until water clear
c.
Dose ICS 02C (acid inhibitor) as acid inhibitor in order to
prevent some corrosion on metal surface from acid.
d.
Slowly dose HCL into circulating tank to dilute with water
and then feed into piping system system by using pump
and keep circulate
e.
Maintain pH < 3 during circulation.
f.
Carry on circulation the chemical solution for 6 – 8 hr
CHEMICAL CLEANING
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
g.
Ref. No. :
Issued Date: 017/06/ 2014
Rev. 0
Page: 9
Check water analysis (Fe2+, Turbidity) every 2 hour. If
Fe2+ or turbidity tendency stable at least 2 sample then
drain all solution
h.
Drain to ditch after neutralization until pH = 6 - 8
STEP 04 – NEUTRALIZATION AND PH CONTROL
Operating condition :
o Pressure
: Atmospheric
o Temperature
: Ambient
Chemical Cleaning Agent :
o NaOH – control pH until 8-9
Procedure :
a. Add the NaOH to the system gradually until the pH raise to
9 – 9.5, but not exceed 10 before entering passivation step
b. Maintain the circulation for at least 1 hour to ensure the pH
9 – 9.5 of the system have uniformly established.
STEP 05 - PASSIVATION
The neutralizing treatment is carried out to stabilize the metallic
surfaces of a system after acid cleaning and for preventing the
corrosion until the system start-up. Especially, the rust prevention of
carbon steel requires sufficient cares because the surface becomes
very active after the acid cleaning.
Chemical :
CHEMICAL CLEANING
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Ref. No. :
Issued Date: 017/06/ 2014
Rev. 0
Page: 10
o Hydrazine 0.05%
o NaOH – control pH 9 – 9.5
Reaction Phenomenon:
N2H4 + 6Fe2O3 4Fe3O4 + 2H2O + N2
agent
N2H4 + O2 2H2O + N2
:
Passivizing
: Oxygen scavenger
Procedure :
a.
Fill up water in the system and circulate
b.
Dose of Sodium hydroxide 50% to the circulation tank
slowly.
c.
Circulate until pH of water circulation is more than 9 then
stop dose NaOH.
d.
Dose of hydrazine to chemical mixing tank and start
circulate
e.
Carry on Circulate for about 4 -8 Hours
f.
Drain the water solution and passivation finished.
STEP 06 – DRYING
a.
Finally, dry the system by blowing with nitrogen
b.
Check oxygen content inside the tube regularly
c.
Stop the nitrogen blowing after oxygen content reaches
<0.5%, hold the nitrogen inside with pressure 0.5 barg.
CHEMICAL CLEANING
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Ref. No. :
Issued Date: 017/06/ 2014
Rev. 0
Page: 11
Figure 1. Flowchart of carbon steel chemical cleaning
Table 1. Job quality plan of carbon steel chemical cleaning
N
o
Process
Chemical used
Condition
Control
Measuring
End point
criteria
Remark
CHEMICAL CLEANING
GENERAL
Industrial Cleaning Services Co.,
Ltd. GUIDELINE AND PROCEDURE
Temp
1
2
Leak test
Alkaline
cleaning
Demin water
ICS 008 0.2%
ambie
nt
ambie
nt
Time
(hou
r)
8
NaOH 0.5%
3
Acid Pickling
HCL 5-10%
inhibitor 1 : 100
HCL
Item
pH
12
pH
any time
every
hour
every
hour
Turbidity
Iron
content
4
Neutralization
NaOH
5
Passivation
Hydrazine 0.05%
6
Dry
plant air
1.
FLOW DIAGRAM
ambie
nt
ambie
nt
ambie
nt
2
pH
12
pH
12
Nitrogen
Issued Date: 017/06/ 2014
Rev. 0
Page: 12
Frequen
cy
Turbidity
ambie
nt
Ref. No. :
every
hour
every
hour
every
hour
No leakage
pH 10-14
Turbidity stable
at least 2 time
add more
chemical if
pH decrease
pH 1-2
Turbidity stable
at least 2 time
Iron contect
stable at least
2 time
add more
chemical if
pH increase
pH 9-10
pH 9-10
O2 content <
0.5%
