panteo - 14-9-2003 at 00:27
Dear Sirs,
Hello, my name is Jae-Hyuk Im.
I'm not sure it's OK to post this message here.
But I desperately need help from expert like you.
Please help me to solve this problem.
I'm working at Fire and Safety division of Huchems fine chemical corporation in Rep' of Korea.
The company's website is http://www.huchems.com.
Next year, we have to carry out the internal inspection of the large CNA storage tanks which are made of aluminum.
The related problems are as follows,
1) We do not have any experience on the internal cleaning for the inspection.
So, we are not sure whether we can carry out the inspection with safely or not.
As Mr.S.P.Arya of Deepak group pointed out, we are afraid of the severe corrosion
caused by diluted NAC during the cleaning work.
2) The CNA tanks have no drain valve. Some 20 tons of NAC can not be pumped out.
3) Production loss during the cleaning and inspection work.
At present, I'm trying to find a company which carried out the internal inspection
of the large CNA storage tank.
I have tried to contact several companies which produce CNA.
So far, I found only two companies with much smaller storage tanks than we have.
1) Deepak group, in India
2) El Dorado Chemical company in USA
We are willing to pay for the information on the required works for the inspection.
(Detailed procedure for emptying, cleaning, waste water disposal, safety)
At least, we need an expert who can make a technical report which explains that the CNA tank can not be emptied for the internal inspection. (We will
use the report to persuade the government authorities.)
Regarding to this matter, I would appreciate it if you could help me to contact a right person or company.
Best regards,
Jae-Hyuk Im
* You can see picture of the CNA storage tanks at the following web page.
http://www.antlove.com/cna_tank.htm
*:"*:"*:"*:"*"*":*":*:"*
Have A Nice Day! (^_^)/
*:"*:"*:"*":*"*":*":*:"*
'==========================================================================================
I exchanged e-mails with Mr.S.P.Arya on the CNA storage tank.
Mr. S. P. Arya
Chief General Manager
Plot K1, MIDC Industrial Area,
P.O.Taloja-A.V-410 208,
Dist: Raigad Maharashtra. India
Phone: (91-22)-741 2411, 741 2412, 741 2810
Fax91-22)-741 2413
Email: aryasp@deepakfertilisers.com
The following e-mail was sent to me from Mr.S.P.Arya on Aug 26.
Dear Mr Jae-Hyuk Im,
I have gone through your email and understood your problem. You can explain to your Inspection Authorities in Korea that cleaning of Aluminium tank is
not possible. In case, you try to clean Aluminium tank with water, it will form weak nitric acid inside the tank and will corrode the tank very fast,
since Aluminium tank is not suitable for Nitric Acid less than 97% concentration.
I am giving below the information you asked for,
1) The Production Manager of our CNA plant is Mr D A Saraiya and the General Manager in-charge of that area is
Mr G Arumugam and their email ids are as follows:-
Mr D A Saraiya - saraiyada@deepakfertilisers.com
Mr G Arumugam - arumugamg@deepakfertilisers.com
Contact Address :-
M/s. Deepak Fertilisers & Petrochemicals Corporation Limited
Plot K-1, MIDC Industrial Area
Taloja, Dist. Raigad, P.B.26
Maharashtra
INDIA
Phone No.: +91 22 27412411, 27412810 to 13
Fax No.: +91 22 27412413
2) There is no specific provision under law for Concentrated Nitric Acid storage tank, however, these are covered under corrosive
substance according to which "Every container having a storage capacity of 20 litres and more and pipelines, fittings etc. used
for storing or carrying corrosive substance shall be examined thoroughly every year for finding out defects and defects shall be
removed forthwith." We are accordingly thoroughly examining storage tanks and pipes externally and carrying out thickness
testing of the same every year.
3) We have emptied out our CNA storage tanks but have never carried out internal inspection of the tank. We are carrying out
inspection as mentioned above under Serial No.2).
4) Life expectancy of Aluminium storage tank depends on the purity of Aluminium metal used. If the purity of Aluminium plates
used for fabricating tank is more than 99.8%, then the life expectancy can be 25-30 years.
5) We have three CNA storage tanks having capacity of 200 MT each.
Regards,
S P ARYA
VICE PRESIDENT (MANUFACTURING)
'==================================================================================
I sent the following e-mail to Mr.S.P.Arya on Aug 13.
Mr. S. P. Arya
Chief General Manager
Plot K1, MIDC Industrial Area,
P.O.Taloja-A.V-410 208,
Dist: Raigad Maharashtra. India
Phone: (91-22)-741 2411, 741 2412, 741 2810
Fax91-22)-741 2413
Email: aryasp@deepakfertilisers.com
Sub: Questions about the CNA Storage tanks ; from Korea
Dear Mr.S.P.Arya,
Hello, my name is Jae-Hyuk Im.
I'm working at Fire and Safety division of Huchems fine chemical corporation in Rep' of Korea.
The company's website is http://www.huchems.com
Huchems corp. is the Korea's largest producer of Concentrated Nitric Acid(CNA: 98%) with a capacity of 104,300 MTPA.
We have two CNA plants designed by CHEMICO(33,000MTPA) and PLINKE(71,300MTPA).
The plants were built in 1979 and 1990. We have two CNA storage tanks made of aluminum.
The capacity of the thanks are 1,360 and 1,019KL each.
As our production quantity is little short of demand, we have to buy some CNA from the other domestic companies.
We use the CNA to produce DNT(Di-nitro-toluene).
The Korean law, revised in 1999, states that the storage tanks for dangerous chemicals of over 1,000 KL capacity must be inspected internally every 10
years.
There has been no need for the internal inspection of the CNA storage tanks according to the previous law.
So, there has been no internal inspection for the CNA storage tanks.
In 1992, we replaced the cone roof of the old CNA tank(1,019KL) while maintaining minimum storage level.
Because of the emptying and cleaning work of the concentrated nitric acid storage tank for the internal inspection is very dangerous, we will request
the government official to lengthen the inspection cycle period from 10 years to 20 years or more.
For over 25 years, nobody performed the internal inspection of the CNA tanks in the company.
Besides the danger relating the task, it will cost too much for us to treat the acidic waste from the CNA tanks.
An operator of the CNA plant told me that lots of white slurry exists in the bottom of the CNA tanks.
The slurry is thought to be aluminum nitrate. Most operators told me that it is impossible to clean the bottom of the CNA tanks.
They curse the Korean law relating the inspection of hazardous chemical storage tanks.
In this regard, I would appreciate it if you could provide me the following information,
1) The contact address of the production manager of the CNA plant
2) The law regarding the internal inspection of the Concentrated Nitric Acid storage tank
3) Emptying experience of the NAC storage tank
4) Life expectancy of an aluminum storage tank
5) Capacity and number of CNA storage tanks
I had worked at an ammonia plant for 9 years.
During that time, I charged the internal inspection of the two large refrigerated ammonia storage tanks.
(The capacity of the tanks was 26,000 KL each)
The emptying, purging and oil removal work for the ammonia tanks were rather easy.
I also performed the internal inspection of the two naphtha storage tanks.
(The capacity of the tanks was 30,000 KL each).
It was easier to inspect the naphtha storage tanks than ammonia storage tanks.
Many thanks in advance,
JaeHyuk Im
vulture - 14-9-2003 at 01:34
Very flattering that you call us experts, but I doubt many members here have experience working on such a large scale.
A possible solution would be dissolving the nitric acid in dichloromethane, but large quantities would be needed and this would also imply other
dangers to the safety of your personnel.
The use of dichloromethane has the advantage that it will cause almost zero corrosion, since it separates the nitric acid from the water, thus
inhibiting formation of H+ which is the main corroding species here.
Please keep us informed, we will try to help you as far as our "expertise" reaches.
EDIT: I assume neutralizing agents or reactions are not possible, because of the large reaction heat?
[Edited on 14-9-2003 by vulture]
PHILOU Zrealone - 13-10-2003 at 05:22
Aluminium resist enough to HNO3 diluted for a transvasement of the remaining bottom CNA and a full cleaning/drying of the installation.
CNA is volatile and boils arround 80°C with emission of nitrous fumes.Al foil stands CNA and it does stand dilute NA for at least 5 days.Here I talk
about less than 0,1 mm foil and your tank is more likely to be > 5 cm.So if you wash it fast enough no noticeable corrosion will
occure...especially if the container is cleaned and dryed and if CNA is again put in it (repassivation will occure).
Al will resist even better if the first neutralisating water contains Na2CO3 (don't use hydroxybase like NaOH since those are prompt to corrode
awfully the Al surface in little time).Na2CO3 will neutralise but don't corrode Al and at worst a thin layer of Al2(CO3)3 will protect the nacked
metal.
True that it is stupid you don't have a bottom outlet that would avoid pumping...since pumps aren't usually done in corrosive resistant
materials.
Note that at such a concentration Fe is passivated by CNA and doesn't corrode but pumps contain also rubber and plastic parts that may not resist
CNA.
Maybe an alternative to conventionnal pumping is peristaltic pumping wich would avoid contact of the metalic parts of the pump with the CNA.The only
need is for a flexible resistant plastic pipe.
The last idea would be a very special diving costume completely hermetic and CNA resistant.
Then internal inspection without emptying the container would be possible.
Alternatively to man a telecommanded submarine with a camrecorder/transmitter could be used!
See you.
Ph Z
Theoretic - 24-10-2003 at 10:51
Aluminium carbonate doesn't exist, actually.
Blind Angel - 24-10-2003 at 15:07
What about a teflon coated vacuum pump?
panteo - 6-11-2003 at 21:39
Our company is looking for a experienced consultant for this matter.
We are willing to pay for the technical info regarding the emptying & cleaning procedure of large CNA tanks.
Regards,