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时间:2013年04月18日 ⁄ 分类: 制药工程 评论:10
11.3.8   Modified Passivation Procedures
11.3.8   修改的钝化规程

A passivation procedure can be modified to deal with a variety of soils, surface finishes and weld area conditions. Adjusting contact times and solution's temperature and concentration would be the simplest way to modify a specific procedure. Sometimes detergent wash or acid wash chemicals are changed or modified with additives to remove certain soils. For example, when removing rouge, solutions containing sodium hydrosulfite can be substituted for the detergent wash step of the procedure. Citric and Phosphoric Acid also could be used as they do have some ability to remove light rouging. Another example would be the use of Hydrofluoric Acid, or more specifically, Ammonium Bifluoride to remove silica scale. The descaling step and associated rinse would necessitate additional steps being added to the standard procedure.

It is important when developing a passivation procedure, that laboratory testing is performed to determine the effectiveness of your procedure. Without preliminary laboratory testing, an educated guess would have to be made and the results may not prove satisfactory.

Below is a guide that can be used for passivating and derouging stainless steel components, piping, and equipment. The chart has some possible options for determination of the contamination and a course of action.

Cleaning and Passivation



Contamination Analytical Method


Cleaning& Passivation Method


System Chemistry




New Component Electropolished电解抛光的新组件





Component Newly Welded






New System – Tubing






Component/System Discolored (Gold Color)






Component/System Discolored (Brown, Red/Brown Color)






Component/System Discolored (Black, Blue/Black Color)






11.3.9   Contamination Analysis
11.3.9   污染分析

Method 1 Filtration of 1 liter sample through a 0.2-0.5 um filter and inspect.

Method 2 Quantitative analysis of the specified metals and organic compounds with wet chemistry techniques or as available.

Method 3 SEM or Auger Electron microprobe/spectroscopy for analysis of surface chemistry and contamination.

11.3.10   Cleaning and Passivation Method
11.3.10   清洁和钝化方法

Method 1 Clean surface with aqueous cleaning solution, apply passivation paste to surface, rinse surface with DI water until traces of chemicals are removed.

Method 2 Circulate cleaning solutions through piping or vessels by circulation method. Circulate cleaning solutions as required by procedure. Circulate passivation solution as per recommended conditions. Rinse surfaces once through with DI water until conductivity of inlet and outlet fluids are within tolerances.

Method 3 Spray cleaning and passivation solutions onto surfaces of vessels, containers, and equipment as per recommended conditions. Rinse surfaces for minimum of 30 minutes per each rinse stage, and perform triple rinse.

Method 4 Soak components or equipment items in treating solutions or tanks as per recommended conditions. The minimum soak time per each solution is two hours. Process requires cleaning, passivation, and rinsing as a minimum. The cleaning system should include circulation, filtration, and heating.

11.3.11   System Chemistry
11.3.11   系统化学作用

Chemistry 1   Nitric acid passivation is performed at Ambient Temperature for 30 to 60 minutes and at 50-60℃ for 20 to 40 minutes.

Chemistry 2   Alkaline degreasing is performed with detergents (phosphates, sodium hydroxide, and potassium hydroxide), pH buffers, and surfactant. The process will remove organic films and particulate debris from the surface of the stainless steel. Utilize approximately 1.0-2.0% detergent, 0.2-0.5% buffer and 0.01-0.2% surfactant.

Chemistry 3   Citric acid/chelant passivation is performed with chelants, reducing agents, surfactants, and pH buffers. These systems are proprietary processes and the exact chemistry and percentages are not available. The chelant systems are able to remove most metal contamination from the surface including iron, manganese, aluminum, and copper. The systems include 3.0-5.0% Citric acid and a variety of chelants, reducing agents, pH buffers, and surfactants.

Chemistry 4   Mineral acid cleaning and passivation can be performed for iron oxide removal or passivation. Typical mineral acids include phosphoric, sulfuric or sulfamic acid. These acids can be utilized at 3.0-10.0% concentrations and at a variety of temperatures. Sulfuric acid is not typically used due to its highly hazardous nature.

Chemistry 5   Intensified acid/chelant systems are utilized for removal of high temperature iron oxide films, silica scales, and organic/carbon films. These systems are a citric based solution with additional organic acids, strong reducing agents, and acid chelants. These systems can use fluorides for silica removal. After strong acid cleaning in a reducing environment, it is recommended that an oxidizing flush be used to ensure oxidation at the surface, removal of organic films, and sanitization of the system.

Chemistry 6   Sodium Hydrosulfite, a strong reducing agent, typically used at 5% by weight at 120 to 160℉ for two to four hours.
化学作用6:次硫酸钠是强还原剂,通常的用法是:在120 to 160℉、5%浓度(重量百分比)下作用2-4小时。

11.3.12   Procedures
11.3.12   规程   Procedure 1   规程1

Clean surface of organic film and other debris.

a) Rinse surface with DI water.

b) Apply gelled acid onto surface at ambient temperature.

c) Brush passivating agent on surface very 15 minutes, maintain a wet surface.

d) After one hour minimum, brush surface with sodium bicarbonate solution until all reaction ceases.

e) Rinse surface with Dl water until all traces of chemicals are removed.
  用去离子水冲洗表面直到所有的化学试剂的痕迹都被去除了。   Procedure 2   规程2

a) Fill system with Dl water and perform leak test with circulation pump.

b) Circulate for a minimum of one to two hours with alkaline degrease stages and heat to 60-80℃ with filtration.

c) Drain and rinse with Dl water.

d) Circulate for a minimum of one to two hours with acid solution and heat to 60-80℃ with filtration.

e) Drain and rinse with Dl water.
  用去离子水引流并冲洗。   Procedure 3   规程3

a) Fill system with Dl water and perform leak test with circulation pump.

b) Circulate for a minimum of two hours with alkaline degrease stages and heat to 60 - 80℃ with filtration.

c) Drain and rinse with Dl water.

d) Circulate for a minimum of eight hours with intensified passivating acid solution and heat to 60 - 80℃.

e) Drain and rinse with Dl water.

f) Flush with oxidizing/sanitization solution.

g) Drain and rinse with Dl water.

11.3.13   Rouging
11.3.13   水锈

Rouging is seen in many water systems, usually high temperature (80℃) distilled water and clean steam systems. Rouge is not limited to storage and distribution systems; it also can be found in distillation and clean steam generating equipment. The main constituent of the rouge film is ferric oxide, but it can contain iron, chromium, and nickel of different forms. From Auger Electron Spectroscopy, it has been found that the outer layer of a rouge film is carbon rich, and the underlying region is iron and oxygen rich, probably iron oxide. Over time, the film uniformly distributes itself throughout the system. The exact mechanism of the rouge formation and proliferation is unknown. Because the phenomenon occurs in systems that offer the most corrosive environment, it is thought that low molecular weight ions of the stainless steel, such as iron, are drawn to the metal surface or are dissolved and uniformly re-deposited throughout the system. Others feel the rouge is an external contaminant probably colloidal in nature that once in the system, uniformly deposits itself.

Rouging would seem to be very site (facility) specific because of the variety in appearance and texture. Rouge can be observed in a variety of colors including; orange, light-red, red, reddish-brown, purple, blue, gray, and black. It can be a very loose film, dust like in appearance and texture that can be readily wiped off to a tight pertinacious film that requires scraping with a sharp instrument to be removed. In addition to the diversification already discussed, rouge can be multi-layered exhibiting different colors and textures. Traditionally the red rouges are most common in high purity high temperature water systems, while the blue/black rouges are typically found in clean steam systems.

Evidence of the migration of rouging in distribution systems can be demonstrated by monitoring a system over a period of time. Key places to look for rouging are still and clean steam generator discharge lines, tank water/vapor interface, pump heads, Teflon® diaphragms on diaphragm valves, interior surface of tank spray ball, and heat effected area of welds. Rouge deposition seems to have an affinity for Teflon® and would be one of the first places to look for signs of system rouging.

In some cases, the rouging appears as quickly as a month or two after system start up. In other cases, it is several years before rouging is observed. In either case rouging is an industry wide phenomena. In a specific case, a facility cold WFI system would re-rouge within a week of being derouged and passivated. The system was derouged and passivated a total of three times. Each time, within a week, the system was totally rouged again. The specific cause was never determined.

The presence of rouge in high purity water systems has not been proven to effect water quality. The FDA has no written position addressing rouging, its existence, or presence in high temperature high purity water clean steam systems. Their criterion has and remains to be in meeting established USP standards for water quality. There is some fear that as the unwanted film develops, it might eventually slough off and be disperse throughput the system. This, in fact, does occur and is manifested in systems with filtered use points. Filters become discolored with the typical reddish-brown rouge color.

Phosphoric, citric, oxalic acids, and ammonium citrates are used depending on the severity of the problem. Oxalic acid solutions are used for the worst cases of rouge. Passivation with nitric acid is required after an oxalic acid rinse.

11.3.14   Preparing Systems for Passivation
11.3.14   钝化的系统准备

Hydrostatic pressure testing is the first test in preparing a system for passivation. All newly constructed or modified systems require pressure testing prior to implementing any chemical procedure. The second check prior to passivation is to confirm the compatibility of the system, its components, and the passivating solutions. This would include in-line instrumentation, flow meters, regulating valves ultraviolet lights, pumps, pump seals, filter membranes, gasket and seal materials, and other specialized in-line devices. The manufacturer or supplier should be consulted to determine whether their equipment is compatible with passivating solutions. Items that are not compatible should be removed from the system and replaced with a blank, valve, spool piece, or temporary jumper hose. In some cases with in-line instrumentation, chemical incompatibility may lie in the effect it has on instrument calibration. Incompatible components should be processed independent of the main system.

Once the system/chemical compatibility has been established, the system to be passivated should be isolated from existing systems, process equipment, utility tie-ins, etc. In most cases, in-line heat exchangers (excluding plate and frame design) and small filter housings (filter elements removed) are left in place and flowed through. This is acceptable as long as the ability to vent and drain is available.

Isolated equipment that requires passivation should be handled independently from the main system unless, by agreement, it is left in-line and flowed through. All isolation points must be valved to avoid forming dead legs in the system being passivated.

Elimination of all dead legs is critical to ensure chemical contact and complete rinsing.

High point vents and low point drains are desirable for complete filling and draining of systems. In distribution systems where high point vents are not installed, high velocity flow and flow restriction techniques can be used to ensure complete filling of the system.

After the system has been pressure tested, compatibility has been confirmed, the system isolated and dead legs valved, consideration must be given to automated controls that govern the system.

Are all the automatic valves operational? 是否所有的自动控制阀运转?

Will valve alignments atypical of normal system operation be permitted? 正常系统运行的阀门的不标准的调整是否是允许的?

Will in-line temperature sensors open diverter valves if unusual temperatures are detected? 当探测到不正常温度时,在线温度感应器是否能打开换向器阀?

Can the desired flow path safely and effectively be achieved.是否能安全有效的达到理想的流动路径?

Passivation contractors generally supply temporary equipment such as circulating vessels, pumps, heat exchangers, flow meters, filters, hoses, spray heads, fittings, specialized adapters or transition fittings, and neutralization vessels. All this equipment should be inspected to assure it meets the requirements for its intended use.

11.3.15   Disposal of Passivation Chemicals
11.3.15   钝化用的化学试剂的处理

Disposal of waste solution is important issue. The chemicals discussed for cleaning and passivating are all water-soluble and can easily be neutralized. Except for heavy metals dissolved in the acid wash solution, the only criterion that makes the waste solutions hazardous is having the pH outside the range of 2 to 12.5. It is the heavy metals contained in the waste effluent that can cause an environmental or disposal problem. Of the 13 priority pollutant metals tested for, two are found in elevated levels in passivation waste effluent waters. The two heavy metals are chromium and nickel.

Fluids discharged must meet the site's discharge temperature requirements.

There are three options for dealing with waste solutions generated when passivating:

•They can be put into chemical drains. This can only be done where compatible drain and treatment systems are available.

•Neutralize waste solutions in contractor-supplied equipment and discharge through chemical drain to site treatment system.

•Off-site disposal is the final option. It is the most costly form of disposal.

Should a site waste treatment system not be available, permission could be obtained from the municipal or private sewer authority to put neutralized waste solutions to sanitary drains. Under no conditions should any waste solutions in any form be permitted to enter storm sewer systems

You will, however, receive documentation confirming proper disposal of waste solutions. Documentation would include a bill of lading or hazardous waste manifest and receipts from the state certified treatment facility where the waste solutions are being transported and treated. When off-site disposal is being used, it is important to verify the credentials of the hauler and final destination site before utilizing their services.

Ultimately, disposing of waste solutions in a proper and legal manner is the responsibility of all involved parties. The owner of the property where the waste solutions are generated, contractors, subcontractors involved with the use of the chemicals, haulers, and the final waste treatment facility would all have some liability for proper disposal of waste solutions.

11.3.16   Documentation
11.3.16   文件

Complete and detailed documentation should be kept as the procedure is being performed. Specifics on chemical concentrations, temperatures, contact time, quality of rinse water supply, and effluent sample readings should all be recorded.

Some contractors use job log sheets to record chronological job data including specifics from the time the contractor arrives on-site until the time he leaves. In addition to job log sheets, passivation log sheets should be completed. Detailed information, as discussed above, can be plugged into a "fill in the blank" form supplied by passivation contractor, validation firm, or owner. No matter how the information is recorded, the important thing is that detailed and accurate documentation is kept. The following information can be submitted to the owner and become incorporated into the final validation documentation:

•Passivation Procedure

•Miscellaneous Pertinent Information

•Procedure Development Data

•Testing Procedure and Equipment

•Pssivation Log Sheets

•Chemical Batch Record Information

•Marked up system drawings, completed using point check list or line identification list.

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