Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/12—Accessories for subsequent treating or working cast stock in situ
  • B22D11/124—Accessories for subsequent treating or working cast stock in situ for cooling
  • B22D11/1245—Accessories for subsequent treating or working cast stock in situ for cooling using specific cooling agents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/12—Accessories for subsequent treating or working cast stock in situ
  • B22D11/124—Accessories for subsequent treating or working cast stock in situ for cooling
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
  • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
  • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
  • C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
  • C23F11/14—Nitrogen-containing compounds

Definitions

• the present invention is directed to the use of the reaction product of alkynediols and polyalkylene polyamine compounds to inhibit intergranular corrosion of metal surfaces in industrial water and process systems, which surfaces are in contact with spray water or condensation.
• the microstructure of metals and alloys is made up of grains, separated by grain boundaries. Intergranular corrosion may be defined as localized attack along the grain boundaries, or immediately adjacent to grain boundaries. Such precipitation can produce zones of reduced corrosion resistance in the immediate vicinity.
• Exfoliation corrosion is a particular form of intergranular corrosion. Exfoliation or delamination presents itself as a loss of metal in layers that appear to follow grain boundaries along the surface.
• the exfoliation in the casters for instance, occurs on the non-wetted structures of the lower segments where direct spray water contact does not occur.
• the steel is exposed to a hot, humid environment in which the surfaces are wetted only by spray water mist or condensation. The corrosion propagates rapidly along the steel surfaces, resulting in the loss of structural integrity of the secondary supporting structure.
• the mechanism for exfoliation corrosion is related to the presence of chlorides in the spray water.
• mist steam
• the heat and humidity evaporates the water from the steel surface, leaving behind a concentrated chloride ion. This process continues, concentrating more and more chloride ions to the point where exfoliation occurs.
• Coupon analysis reveals that the corrosion mechanism occurs as follows: The chloride ion that is deposited on the metal surface migrates through the brittle layer of corrosion product/deposit that is generated. Under the deposit, a transient iron chloride salt is generated. The salt is hygroscopic (moisture absorbing) and undergoes hydrolysis, creating acid chloride conditions. Additional iron oxide corrosion products are left behind as the acidic corrosion front advances deeper into the metal surface.
• the present invention is directed toward methods for inhibiting the intergranular corrosion of metal surfaces in industrial processing systems, e.g., steam and cooling water systems, which surfaces are in contact with spray water or condensation, which comprises adding to the spray water a sufficient corrosion inhibiting amount of the reaction product of an alkynediol and a polyalkylene polyamine.
• the alkynediols and alkenediols taught to be effective in producing the reaction product are those containing four to twelve carbon atoms.
• the alkynediols contain four carbon atoms.
• An exemplary alkynediol is butynediol.
• the polyalkylene polyamine compounds taught to be effective in producing the reaction product are those containing two to ten amine groups, and preferably, three to seven amine groups. These amine groups may be substituted or unsubstituted, and each is separated by an alkylene group having from one to six carbon atoms, with two to four being preferred.
• Exemplary polyamines include ethylene diamine, diethylene triamine, pentaethylene hexamine, pentapropylene hexamine, triheptylene diamine, and the like.
• the weight ratio of the reactants are such as to attain full reaction between the respective ingredients with weight ratios of amine to diol of 4:1 to 1:1, with 3:1 being preferred.
• An ionizable compound of copper, such as copper acetate, is employed in this reaction in catalytic amounts.
• the reaction product of the present invention may be added to the spray water in an amount which is sufficient to inhibit corrosion of the metal surfaces.
• the reaction product may be added to a supply line in an amount ranging from 0.5 parts to about 500 parts per million parts of water present in the supply line. Preferably, about 1 to 100 parts per million parts water are added, with about 5 to 10 parts per million parts water particularly preferred.
• the reaction product of the present invention is added to the supply line in either a solvent or in neat form.
• the reaction product is added in an aqueous solvent, of which water is an example.
• the reaction product can be added to the spray water along with other suitable ingredients, such as antifoams, corrosion inhibitors, and the like.
• the spray water is typically at a temperature of from about 110-180° F. in the systems to be treated.
• Coupons tested included: mild steel, stainless steel, copper and coated mild steel.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Preventing Corrosion Or Incrustation Of Metals (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Citations (3)

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• 2002
  • 2002-10-30 US US10/283,457 patent/US20040086419A1/en not_active Abandoned
• 2003
  • 2003-09-10 DE DE60312202T patent/DE60312202T2/de not_active Expired - Lifetime
  • 2003-09-10 CA CA002504421A patent/CA2504421A1/en not_active Abandoned
  • 2003-09-10 NZ NZ540134A patent/NZ540134A/en not_active IP Right Cessation
  • 2003-09-10 AU AU2003267075A patent/AU2003267075B2/en not_active Expired
  • 2003-09-10 KR KR1020057007590A patent/KR101058965B1/ko active IP Right Grant
  • 2003-09-10 RU RU2005116268/02A patent/RU2320778C2/ru not_active IP Right Cessation
  • 2003-09-10 JP JP2004549947A patent/JP4424671B2/ja not_active Expired - Fee Related
  • 2003-09-10 CN CNB038256347A patent/CN100425735C/zh not_active Expired - Lifetime
  • 2003-09-10 AT AT03749550T patent/ATE355402T1/de not_active IP Right Cessation
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  • 2003-09-10 WO PCT/US2003/028266 patent/WO2004042115A1/en active IP Right Grant
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  • 2003-09-10 BR BRPI0315190-5A patent/BR0315190B1/pt active IP Right Grant
  • 2003-09-10 PL PL03376482A patent/PL376482A1/xx unknown
  • 2003-10-09 UA UAA200505034A patent/UA80451C2/uk unknown
• 2005
  • 2005-05-16 ZA ZA200503934A patent/ZA200503934B/en unknown

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