Passivation

Passivation is the process of making a material "passive" in relation to another material prior to using the materials together. For example, prior to storing hydrogen peroxide in an aluminium container, the container can be passivated by rinsing it with a dilute solution of nitric acid and peroxide alternating with deionized water. The nitric acid and peroxide oxidizes and dissolves any impurities on the inner surface of the container, and the deionized water rinses away the acid and oxidized impurities. Another typical passivation process of cleaning stainless steel tanks involves cleaning with NaOH and citric acid followed by nitric acid (up to 20% at 120F) and a complete water rinse. This process will restore the film, remove metal particles, dirt, and welding generated compounds (e.g. oxides).
In the context of corrosion, passivation is the spontaneous formation of a hard non-reactive surface film that inhibits further corrosion. This layer is usually an oxide or nitride that is a few atoms thick.


Passivation is a process performed to make a surface passive, i.e., a surface film is created that causes the surface to lose its chemical reactivity. Passivation unipotentializes the stainless steel with the oxygen absorbed by the metal surface, creating a monomolecular oxide film. Passivation can result in the very much-desired low corrosion rate of the metal.
It is seen that most of the fabricators are using the passivation solution for only the weld pool line or the heat dissipation areas. But that doesn’t ensures from risk of corrosion since the pitting on the remaining surface remain untreated as well as the corrosion susceptible gray zone remains forever. The simple spatters of the grinding also get indented into the surface and it causes the seeding for the corrosion. The chromium in the Stainless steel is playing anticorrosive roll in the play by forming the Cr2O3 Chromic Oxide. But it doesn’t guard against free ferrite on the surface.
With our passivation treatment on total area the there is hardly any corrosion susceptibility since all dirt is dissolved and the surface gets converted to the higher oxidation status as uniform film it becomes redundant to further corrosive attacks.
The passivation cost per square meter area is very less against the life and quality it ensures to the precision products.So we recommend always to go for total Passivation.

Mechanisms of passivation
Under normal conditions of pH and oxygen concentration, passivation is seen in such materials as aluminium, iron, zinc, magnesium, copper, stainless steel, titanium, and silicon. Ordinary steel can form a passivating layer in alkali environments, as rebar does in concrete. The conditions necessary for passivation are recorded in Pourbaix diagrams.
Some corrosion inhibitors help the formation of a passivation layer on the surface of the metals to which they are applied.

Electrochemical passivation processes
Some compounds, dissolving in solutions (chromates, molybdates) form non-reactive and low solubility films on metal surfaces.

Passivation of specific materials
Aluminium may be protected from oxidation by anodizing and/or allodizing (sometimes called Alodining), or any of an assortment of similar processes. In addition, stacked passivation techniques are often used for protecting aluminium. For example, chromating is often used as a sealant to a previously-anodized surface, to increase resistance to salt-water exposure of aluminium parts by nearly a factor of 2 versus simply relying on anodizing.
Iron based (ferrous) materials, including steel, may be somewhat protected by promoting oxidation ("rust") and then converting the oxidation to a metalophosphate by using phosphoric acid and further protected by surface coating. As the uncoated surface is water-soluble a preferred method is to form manganese or zinc compounds by a process commonly known as Parkerizing. Older, less-effective but chemically-similar electrochemical conversion coatings included bluing, also known as black oxide.
Nickel can be used for handling elemental fluorine, thanks to a passivation layer of nickel fluoride.

Terminology for assorted passivation processes
Bluing, also known as black oxide, and sometimes called browning when used in reference to historical processes dating from the 18th Century, is a passivation coating for the surfaces of iron and steel objects. It is one of the oldest passivation processes.
Newer, proprietary (and/or trademarked) processes for conversion coatings include Parkerized for passivating steel, dating to roughly 1912, and Alodine for passivating aluminium; both are trademarked processes and are now owned by Henkel Surface Technologies.
Chem film is any generic chromate conversion coating used to passivate aluminium. One such example is U.S. Patent 5,304,257. In general, however, chromate can also mean any of several chromate conversion coatings that can be applied to a much wider range of metals and alloys than just to aluminium. In recent years, chromate coatings have become less popular due to concerns over environmental pollution from using such processes.
Iridite is another trademarked name of a whole family of proprietary conversion coatings owned by MacDermid. A competing conversion coating used on aluminium, that somewhat ameliorates the environmental pollution concerns caused by chromate coatings, it often appears as a slightly yellowish coating, of roughly the same color as a yellow highlighting pen used to mark text on paper.

Rationale for passivating aluminium
Aluminium naturally forms an oxide almost immediately that protects it from further oxidation in many environments. This naturally-occurring oxide provides no protection during exposure to any saltwater spray environments, such as occurs in areas near bodies of saltwater. In such coastal environments, unprotected aluminium will turn white, corrode, and largely vanish over periods of exposure as short as a few years. The only way to prevent this from occurring is to use a more robust conversion coating on aluminium surfaces that will not be affected by the saltwater atmosphere. Alodine, Iridite, and chem film coatings can provide varying amounts of protection for aluminium surfaces.

"Saudi King: 'We will pump more oil'

Claiming a quarter of the world's proven oil reserves and some of its lowest production costs, Saudi Arabia was producing around 9.2 million barrels per day (1.46×106 m3/d) of oil at the beginning of 2008
According to British Petroleum Statistical Review of World Energy, as of 2007 Saudi Arabia reported it had 264 billion barrels (42×109 m3) of estimated oil reserves, around 21% of conventional world oil reserves.
Since Saudi Arabia produced about 3.2 billion barrels (510×106 m3) of oil in 2006, this would give it over 80 years of reserves at current rates of production.
Although Saudi Arabia has around 80 oil and gas fields, more than half of its oil reserves are contained in only eight fields, and more than half its production comes from one field, the Ghawar field.The raw data are not available to outside scrutiny.
A dissenting opinion regarding Saudi oil reserves came from Matthew Simmons who claimed in his 2005 book "Twilight in the Desert" that Saudi Arabia's oil production faces near term decline, and that it will not be able to consistently produce more than current levels.
In addition to his belief that the Saudi fields have hit their peak, Simmons also argues that the Saudis may have irretrievably damaged their large oil fields by overpumping salt water into the fields in an effort to maintain the fields' pressure and thus make the oil easier to extract.
Since 1982 the Saudis have withheld their well data and any detailed data on their reserves, giving outside experts no way to verify the overall size of Saudi reserves and output. After US President Bush asked the Saudis to raise production on a visit to Saudi Arabia in January 2008, and they declined, Bush questioned whether they had the ability to raise production any more. In the summer of 2008, Saudi Arabia announced an increase in planned production of 500,000 barrels per day.Penketh, Anne.

DECONTAMINATION SPECIALIST

Chemical Decontamination

With PSC OZEST Life Guard™ decontamination programs, benzene and other hazards associated with refinery and petrochemical processing can be eliminated in a fraction of the time normally associated with a shutdown. PSC OZEST provides technical refinery expertise to enhance our turnkey service and to insure that every detail is properly addressed. The processes apply to crude units, FCCU units, lube oil plants, ethylene and butadiene plants as well. Our programs combine unique, environmentally safe chemical products with sate-of-the-art mobile pump and filtration systems. Furthermore, we can customize the service for various plant equipment including refinery distillation and fractionation towers, accumulators, drums, reactors and exchangers. It also safely removes Pyrophoric Iron Sulfides and residual H2S using second stage process that takes only 4 – 6 hours in most cases.

The Life guard chemical was developed and patented by PSC.

In general the client will determine what equipment within the unit is to be decontaminated. PSC OZEST will design a detailed procedure with regards to the most cost effective circulation loops. Upon approval of the detailed procedure PSC OZEST ties in the pump/filtration equipment and other accessories. A special formulated decontaminating solution is circulated for several hours at rates up to 2,000 gpm, filtering out solids down to 40 microns, if necessary.The emulsion that is formed is then broken down in a fracturing tank using a demulsifier to allow recovery of the hydrocarbon that is removed from the process equipment. The subsequent aqueous phase is discharged to the plant’s API or waste treatment facility. PSC OZEST closed loop system Life Guard™ makes EPA and OHSA compliance much easier to achieve.The major benefits are:

■ Zero LEL
■ Zero H2S
■ Less than 0.5 ppm Benzene
■ No steaming out or Nitrogen purging required
■ Less heat exchangers to be pulled during the shutdown, if included in the process.
■ Time saving.
■ Pyrophoric materials will be oxidized
■ Partial scales removal (when scale is bounded with hydrocarbon)
The Life Guard is
■ Neutral
■ Biodegradable
■ Has no impact on any material
■ Very powerful emulsifier
■ Can be easily Broken back into Oil & Water
■ More than 2000 projects worldwide including Saudi Arabia
■ Approved by CSDC ( Aramco ) & used in Ras Tanurah Ref, Riyadh Ref, Jeddah Ref, Yanbu Ref, Lub Ref, Sam Ref , Sas Ref, etc.
PSC OZEST offer more than a chemical-cleaning vendor does. We take a comprehensive approach, as if the refinery belongs to us. OZEST walks every job and with the continuous support of PSC designs the most efficient circulation loops to facilitate the decontamination of entire crude units and coker units. OZEST’s customers offer the best support to the effectiveness of our decontamination processes.