Wet air oxidation installed cost

[JohnO Regan]

We are looking for a way to deal with a 5 m3 per hour waste caustic stream contaminated with sulphide, mercaptans and organics . C.O.D is approximately 40 grams per litre. We believe that wet air oxidation offers a good solution.
We are struggling to understand the total cost of installation including the capital equipment. Suppliers have provided widely different prices for the same application.
Can anyone provide me with a historical installed cost of a wet air oxidation unit including all services and utilities tie in ?

 

[MJCronin]

Nasty waste streams frequently demand premium materials which pushes costs up ... Nickel based alloys are currently very expensive.

Is the MOC plastic or fiberglass ?.... More details please

I am assuming that Austenitic Stainless Steels may be unacceptable

Suggest that you get a requote from all suppliers with the most premium corrosion resistant materials and the least cost materials

You will then know where you stand.

Please supply more details of the design, configuration and performance requirements

Regards

MJCronin
Sr. Process Engineer

 

[JohnO Regan]

Objective is to reduce the C.O.D as much as possible but definitely o less than 10,000 mg/l. Sulphide must be reduced to less than 1 mg/l.

 

[pierreick]

Hi,
Consider this literature to support your work :

https://www.intechopen.com/chapters/48758

You need to define a clear scope and submit it to reputable companies to get a proper quote ( big names and local contractors)
Flow rate , permanent or batch ?
Temperature? Pressure ?
Compositions ( COD , salt , chemical analysis ) to determine the treatment and the metallurgy of the equipment.
Objective ( specification at the outlet of the unit) , COD ,.... Off gas treatment if needed .

then you should be able to compare the process, the operating cost , the investment (capex) .

Note : Consider to talk to your local EPA about your project , these days regulation are tougher and your process may not be suitable with EPA's requirement

my 2 cents
Pierre

 

[shvet]

Spent caustic neutralization is not a simple process. This is the reason it is subject to licensing. Upstream process where spent caustic is generated is a key to an answer you seek.

Treatment/regeneration of spent caustic generated during mercaptans removal is subject to dedicated patented processes. See Merichem's MERICON/REGEN and UOP's Merox as examples. Be ready that:
- mercaptans removal to be done with Cd-containing catalyst (fixed bed or dissolved - depends on Licensor) which is toxic to environment
- spent air has extremely low odor threshold
- in case of batch neutralization spent gas has high concentration of H2S during start of cycle even caustic has traces of sulfides

Temperature of treatment/regeneration to be maintained well below 50°C (120°F). In this case corrosion rate caused by sulfonic acid is low. Note that SS will not help in case of sulfonic acid corrosion. See API 571 fig. 5-80 and related paragraphs for details.

Final cost depends on:
- input data you provided to suppliers
- experience and reputation of suppliers
- technology you chose
- options (incineration of spent air, disulfide oil handling, oxidizer type, neutralization spent gas handling etc.)
As per my experience options can be as expensive as core process unit. I have met situation when incinerator had more total installation cost then core process unit had (oxidizer+disulfide separator).

 

[JohnO Regan]

Thank you for your comprehensive comments.
It is indeed becoming more clear that the W.A.O quoted by the supplier is going to be only a fraction of the installed cost.