WO2003018861A1 - Procede permettant de rendre des metaux resitants a la corrosion - Google Patents

Procede permettant de rendre des metaux resitants a la corrosion Download PDF

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Publication number
WO2003018861A1
WO2003018861A1 PCT/NL2001/000644 NL0100644W WO03018861A1 WO 2003018861 A1 WO2003018861 A1 WO 2003018861A1 NL 0100644 W NL0100644 W NL 0100644W WO 03018861 A1 WO03018861 A1 WO 03018861A1
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WO
WIPO (PCT)
Prior art keywords
urea
process according
maximum
peroxide
perborate
Prior art date
Application number
PCT/NL2001/000644
Other languages
English (en)
Inventor
Johannes Henricus Mennen
Tjay Tjien Tjioe
Paulus Lambertus Alsters
Johan Jozef Ghislain Thoelen
Mathieu Johannes Guillaume Notten
Jan Wiebe Werf Van Der
Original Assignee
Dsm Ip Assets B.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dsm Ip Assets B.V. filed Critical Dsm Ip Assets B.V.
Priority to CNA018235948A priority Critical patent/CN1545565A/zh
Priority to CA002457200A priority patent/CA2457200A1/fr
Priority to PCT/NL2001/000644 priority patent/WO2003018861A1/fr
Priority to JP2003523704A priority patent/JP2005501178A/ja
Publication of WO2003018861A1 publication Critical patent/WO2003018861A1/fr

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Classifications

    • 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
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/40—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using liquids, e.g. salt baths, liquid suspensions
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten

Definitions

  • the invention relates to a process for rendering metals corrosion resistant by treating them with an anti-corrosion agent.
  • an oxidizer is often added to the plant as anti-corrosion agent in order to protect metallic materials of construction against corrosion.
  • an oxide scale develops on the metal parts, which protects against corrosion.
  • This process is also known as passivation of the metal.
  • Customary passivating agents are oxygen or an oxygen-releasing compound as described in for example US-A-2.727.069, where preferably oxygen in the form of air is employed in a urea process.
  • the passivating agent is added to for example one of the raw materials but may be introduced into the plant in various locations.
  • the amount of oxygen used according to US-A-2.727.069 is 0.1-3 percent by volume relative to the amount of CO 2 when used in a, urea plant fabricated from chromium nickel steel preferably containing 16-20% chrome, 10-14% nickel and 1.75-4% of a metal belonging to the group of molybdenum and zirconium. Although such addition of oxygen/air protects the metallic materials of construction against corrosion, it has a number of drawbacks:
  • the raw materials for example urea production (ammonia and carbon dioxide) as delivered from a modern ammonia plant invariably contain traces of hydrogen. These, in combination with the passivating air added, may lead to the formation of flammable hydrogen/air mixtures in particular plant areas.
  • WO-95/00674 describes the application of a duplex steel grade in urea plants and refers to omission of the passivating gas.
  • Duplex steel is a stainless steel with a ferritic-austenitic structure with the two phases having different compositions.
  • the duplex structure means that chromium and molybdenum are predominantly present in the ferrite phase and nickel and nitrogen in the austenite phase.
  • Duplex steel may be used especially in urea plants, where it comes into contact with the corrosive ammonium carbamate solutions and it may successfully be used particularly in the high-pressure section of urea plants.
  • the most critical items such as the cladding of high-pressure vessels, heat exchanger tubes, seals around manholes, piping, flanges and valves are manufactured from duplex steel.
  • duplex steel may be improved by utilizing a ferritic-austenitic duplex steel having a chromium content of between 28 and 35 wt% and a nickel content of between 3 and 10 wt% with an oxidizer being brought into contact with the metal parts and with the passivating air being completely or partly omitted. In particular, the passivating air is completely omitted.
  • oxidizers use is preferably made of peroxides, perborates, percarbonates, nitrites, nitrates, oxides of nitrogen or trivalent metal ions or a mixture of these oxidizers.
  • 0.001-1.5 wt% peroxide, percarbonate, perborate, nitrite, nitrate, oxide of nitrogen or a trivalent metal ion or a mixtures of these oxidizers is added relative to the amount of fresh raw materials used. If, besides an oxidizer, passivating air is added, the amount of passivating air will be such as to produce an oxygen concentration in the carbamate-containing liquid streams of less than 2 ppm, preferably less than 1 ppm.
  • the oxidizer is particularly added to the high-pressure section of a urea plant, more particularly to a point between the high-pressure reactor and the high-pressure stripper of a urea plant. If the oxidizers are gaseous or may be rendered gaseous, they are preferably introduced into the urea process via the feedstocks ammonia and carbon dioxide. If the oxidizers are added to the high- pressure section of a urea plant as a liquid or solid, this is preferably effected via the recirculated carbamate stream coming from the further recovery of the urea solution that has formed. As peroxides use is preferably made of hydrogen peroxide or a peroxide of an earth alkali metal, for example barium peroxide.
  • Organic peroxides for example urea peroxide may also be used.
  • perborate use is made of for example sodium perborate or potassium perborate.
  • Sodium percarbonate is used as percarbonate.
  • nitrate and/or nitrite use is made of for example the sodium salts or potassium salts or nitric acid and/or nitrous acid.
  • trivalent metal ion use is made of for example ferrisalts.
  • an austenitic-ferritic duplex steel with the following composition is used:
  • Ce maximum 0.2 wt.% the balance consisting of Fe and common impurities and additives and the ferrite content ranging from 30 to 70 vol%.
  • the C content is maximum 0.03 wt.% and in particular maximum 0.02 wt.%, the Si content is maximum 0.5 wt.%, the Cr content
  • the ferrite content is more preferably 30-55 vol%.
  • the Cr content of the austenite phase is more preferably at least 25 wt.% and in particular at least
  • Urea may be prepared by introducing (excess) ammonia and carbon dioxide into a synthesis zone at a suitable pressure (for example 12-40 MPa) and a suitable temperature (for example 160-250°C), which first results in the formation of ammonium carbamate according to the reaction:
  • the theoretically attainable conversion of ammonia and carbon dioxide into urea is determined by the thermodynamic position of the equilibrium and depends on for example the NHs/CO ⁇ ratio (N/C ratio), the H 2 O/CO 2 ratio and temperature, and can be calculated with the aid of the models described in for example Bull, of the Chem. Soc. of Japan 1972, Vol. 45, pages 1339-1345 and J. Applied Chem of the USSR (1981), Vol. 54, pages 1898-1901.
  • a urea synthesis solution which consists essentially of urea, water, ammonium carbamate and unbound ammonia.
  • a gas mixture of unconverted ammonia and carbon dioxide along with inert gases. Ammonia and carbon dioxide are removed from this gas mixture and are preferably returned to the synthesis zone.
  • urea was prepared in so-called conventional high-pressure urea plants, which at the end of the 1960s were succeeded by processes carried out in so-called urea stripping plants.
  • a conventional high-pressure urea plant is understood to be a urea plant in which the ammonium carbamate that has not been converted into urea is decomposed, and the customary excess ammonia is expelled, at a substantially lower pressure than the pressure in the synthesis reactor itself.
  • the synthesis reactor is usually operated at a temperature of 180-250°C and a pressure of 15-40 MPa.
  • a conventional high-pressure urea plant Following expansion, dissociation and condensation at a pressure of between 1.5 and 10 MPa, the reactants that are not converted into urea are returned to the urea synthesis as a carbamate stream.
  • ammonia and carbon dioxide are fed directly to the urea reactor.
  • the N/C ratio in the urea synthesis in a conventional high-pressure urea process is between 3 and 5 and CO 2 conversion between 64 and 68%.
  • a urea stripping plant is understood to be a urea plant in which the ammonium carbamate that has not been converted into urea is largely decomposed, and the customary excess ammonia is largely expelled, at a pressure that is essentially almost equal to the pressure in the synthesis reactor. This decomposition/expulsion takes place in a stripper with or without addition of a stripping agent. In a stripping process, carbon dioxide and/or ammonia may be used as stripping gas before these components are added to the reactor.
  • Such stripping is effected in a stripper installed downstream of the synthesis reactor; in it, the urea synthesis solution coming from the urea reactor, which contains urea, ammonium carbamate and water as well as ammonia, is stripped with the stripping gas with addition of heat. It is also possible to use thermal stripping here. Thermal stripping means that ammonium carbamate is decomposed and the ammonia and carbon dioxide present are removed from the urea solution exclusively by means of the supply of heat. Stripping may also be effected in two or more steps. In a known process a first, purely thermal stripping step is followed by a CO2 stripping step with addition of heat. The gas stream containing ammonia and carbon dioxide exiting from the stripper is returned to the reactor whether or not via a high-pressure carbamate condenser.
  • the synthesis reactor In a urea stripping plant the synthesis reactor is operated at a temperature of 160-240°C and preferably at a temperature of 170-220°C.
  • the pressure in the synthesis reactor is 12-21 MPa, preferably 12.5-19.5 MPa.
  • the N/C ratio in the synthesis in a stripping plant is between 2.5 and 4 and CO 2 conversion between 58 and 65%.
  • the synthesis may be carried out in one or two reactors. When use is made of two reactors, the first reactor, for example, may be operated using virtually fresh raw materials and the second using raw materials entirely or partly recycled, for example from the urea recovery section.
  • a frequently used embodiment for the preparation of urea by a stripping process is the Stamicarbon CO 2 stripping process as described in European Chemical News, Urea Supplement, of 17 January 1969, pages 17-20.
  • the greater part of the gas mixture obtained in the stripping operation is condensed and adsorbed in a high-pressure carbamate condenser, after which the ammonium carbamate stream formed is returned to the synthesis zone for the formation of urea.
  • the high-pressure carbamate condenser may de designed as, for example, a so-called submerged condenser as described in NL-A-8400839.
  • the submerged condenser can be placed in horizontal or vertical position. It is, however, particularly advantageous to carry out the condensation in a horizontal submerged condenser (a so-called pool condenser; see for example Nitrogen No 222, July-August 1996, pp. 29-31).
  • the pressure of the stripped urea synthesis solution is reduced to a low level in the urea recovery and the solution is evaporated, after which urea is released and a low-pressure carbamate stream is circulated to the synthesis section.
  • the present process is highly suitable for improving and optimizing existing urea plants by replacing piping and equipment items in areas where corrosion occurs with duplex steel piping and equipment items that are passivated in accordance with the present invention.
  • the process is also particularly suitable for revamping existing urea plants by applying the steel grade together with the passivating technique according to the present invention in areas where hairline cracks may develop in duplex steel overlay welds.
  • the invention may be applied in all current urea processes, both conventional urea processes and urea stripping processes.
  • conventional urea processes in which the invention may be applied are the so- called 'Once-Through', Conventional 'Recycling' and Heat Recycling Processes.
  • urea stripping processes in which the invention may be applied are the CO 2 stripping process, the NH 3 stripping process, the self-stripping process, the ACES (Advanced Process for Cost and Energy Saving) process, the IDR (Isobaric-Double-Recycle) process and the HEC process.
  • Example I A quartz tube in an inertized autoclave was filled with 36 g of urea, 17.5 g of a 3% hydrogen peroxide solution, 20 g of carbon dioxide and 34 g of ammonia. An austenite-ferrite duplex steel specimen with a surface area of 36 cm 2 was introduced into the tube. The system was heated to 184°C, resulting in a pressure of 148 bar. After five days the system was cooled and depressuhzed. Upon removing the specimen, less than 3 mg of iron, chromium and nickel was found in the remaining urea slurry.
  • Example I The experiment in Example I was conducted except that 17 g of water was used in place of 17.5 g of a 3% hydrogen peroxide solution. The other components were the same. Upon removing the specimen, 12 mg of iron, chrome and nickel was found in the remaining urea slurry.
  • Example II A quartz tube in an inertized autoclave was filled with 36 g of urea, 18 g of a 5% sodium nitrite solution, 20 g of carbon dioxide and 34 g of ammonia. An austenite-ferrite duplex steel specimen with a surface area of 36 cm 2 was introduced into the tube. The system was heated to 184°C, resulting in a pressure of 148 bar. After five days the system was cooled and depressuhzed. Upon removing the specimen, less than 3 mg of iron, chromium and nickel was found in the remaining urea slurry.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

L'invention concerne un procédé permettant de rendre des métaux résistants à la corrosion au moyen d'un traitement avec un agent anticorrosion, un acier duplex ferritique-austénitique présentant un contenu de chrome compris entre 28 et 35% en poids et un contenu de nickel compris entre 3 et 10% en poids étant utilisé, un oxydant étant mis en contact avec les parties métalliques, et l'air de passivation étant complètement ou partiellement omis.
PCT/NL2001/000644 2001-08-31 2001-08-31 Procede permettant de rendre des metaux resitants a la corrosion WO2003018861A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
CNA018235948A CN1545565A (zh) 2001-08-31 2001-08-31 使金属耐腐蚀的方法
CA002457200A CA2457200A1 (fr) 2001-08-31 2001-08-31 Procede permettant de rendre des metaux resitants a la corrosion
PCT/NL2001/000644 WO2003018861A1 (fr) 2001-08-31 2001-08-31 Procede permettant de rendre des metaux resitants a la corrosion
JP2003523704A JP2005501178A (ja) 2001-08-31 2001-08-31 金属を耐腐食性にする方法

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/NL2001/000644 WO2003018861A1 (fr) 2001-08-31 2001-08-31 Procede permettant de rendre des metaux resitants a la corrosion

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WO2003018861A1 true WO2003018861A1 (fr) 2003-03-06

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CN (1) CN1545565A (fr)
CA (1) CA2457200A1 (fr)
WO (1) WO2003018861A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1688511A1 (fr) * 2005-02-02 2006-08-09 DSM IP Assets B.V. Procédé pour la production d'urée dans une usine conventionelle d'urée
WO2014192823A1 (fr) * 2013-05-28 2014-12-04 東洋エンジニアリング株式会社 Procédé de synthèse d'urée
EP2500444A4 (fr) * 2009-11-13 2017-10-25 Nippon Steel & Sumitomo Metal Corporation Acier inoxydable duplex ayant une excellente résistance aux alcalins

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2107051A1 (fr) * 2008-04-02 2009-10-07 DSM IP Assets B.V. Procédé pour augmenter la capacité d'une installation de production d'urée existante
CN102099500B (zh) * 2008-07-23 2013-01-23 新日铁住金不锈钢株式会社 尿素水箱用铁素体系不锈钢
FI125854B (fi) * 2011-11-04 2016-03-15 Outokumpu Oy Dupleksi ruostumaton teräs
CN103451664A (zh) * 2013-08-23 2013-12-18 苏州长盛机电有限公司 一种链条的钝化方法
CN106362570B (zh) * 2016-08-27 2019-02-05 湖北宜化集团有限责任公司 一种三聚氰胺中含co2尾气的回收方法及装置
CN107904522A (zh) * 2017-10-18 2018-04-13 江苏理工学院 一种高强度的双相不锈钢合金及其制备方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2727069A (en) * 1953-04-15 1955-12-13 Stamicarbon Preparation of urea
US3720548A (en) * 1970-04-02 1973-03-13 Stamicarbon Process for increasing the corrosion resistance of austenitic stainless steels
US4591644A (en) * 1983-12-21 1986-05-27 Stamicarbon B.V. Method and installation for the preparation of melamine
EP0504621A1 (fr) * 1991-03-18 1992-09-23 Urea Casale S.A. Méthode pour la passivation de surfaces de métaux attaquées par des conditions opérationelles et des agents favorisant la corrosion
US5582656A (en) * 1993-06-21 1996-12-10 Sandvik Ab Ferritic-austenitic stainless steel

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2727069A (en) * 1953-04-15 1955-12-13 Stamicarbon Preparation of urea
US3720548A (en) * 1970-04-02 1973-03-13 Stamicarbon Process for increasing the corrosion resistance of austenitic stainless steels
US4591644A (en) * 1983-12-21 1986-05-27 Stamicarbon B.V. Method and installation for the preparation of melamine
EP0504621A1 (fr) * 1991-03-18 1992-09-23 Urea Casale S.A. Méthode pour la passivation de surfaces de métaux attaquées par des conditions opérationelles et des agents favorisant la corrosion
US5582656A (en) * 1993-06-21 1996-12-10 Sandvik Ab Ferritic-austenitic stainless steel

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1688511A1 (fr) * 2005-02-02 2006-08-09 DSM IP Assets B.V. Procédé pour la production d'urée dans une usine conventionelle d'urée
WO2006083166A1 (fr) * 2005-02-02 2006-08-10 Dsm Ip Assets B.V. Procédé de production de mélaminés dans une installation de production de mélaminés
EP2500444A4 (fr) * 2009-11-13 2017-10-25 Nippon Steel & Sumitomo Metal Corporation Acier inoxydable duplex ayant une excellente résistance aux alcalins
WO2014192823A1 (fr) * 2013-05-28 2014-12-04 東洋エンジニアリング株式会社 Procédé de synthèse d'urée
GB2530447A (en) * 2013-05-28 2016-03-23 Toyo Engineering Corp Urea synthesis method
JPWO2014192823A1 (ja) * 2013-05-28 2017-02-23 東洋エンジニアリング株式会社 尿素合成方法
GB2530447B (en) * 2013-05-28 2020-02-26 Toyo Engineering Corp Urea synthesis method

Also Published As

Publication number Publication date
JP2005501178A (ja) 2005-01-13
CN1545565A (zh) 2004-11-10
CA2457200A1 (fr) 2003-03-06

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