EP2215421A1 - Utilisation d'un acier inoxydable duplex dans un système de production d'acide phosphorique - Google Patents

Utilisation d'un acier inoxydable duplex dans un système de production d'acide phosphorique

Info

Publication number
EP2215421A1
EP2215421A1 EP08841210A EP08841210A EP2215421A1 EP 2215421 A1 EP2215421 A1 EP 2215421A1 EP 08841210 A EP08841210 A EP 08841210A EP 08841210 A EP08841210 A EP 08841210A EP 2215421 A1 EP2215421 A1 EP 2215421A1
Authority
EP
European Patent Office
Prior art keywords
max
phosphoric acid
stainless steel
duplex stainless
heat exchanger
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP08841210A
Other languages
German (de)
English (en)
Other versions
EP2215421A4 (fr
Inventor
Sabina Ronneteg
Knut Tersmeden
Anna-Lena NYSTRÖM
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sandvik Intellectual Property AB
Original Assignee
Sandvik Intellectual Property AB
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 Sandvik Intellectual Property AB filed Critical Sandvik Intellectual Property AB
Publication of EP2215421A1 publication Critical patent/EP2215421A1/fr
Publication of EP2215421A4 publication Critical patent/EP2215421A4/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
    • F28F21/08—Constructions of heat-exchange apparatus characterised by the selection of particular materials of metal
    • F28F21/081—Heat exchange elements made from metals or metal alloys
    • F28F21/082—Heat exchange elements made from metals or metal alloys from steel or ferrous alloys
    • F28F21/083—Heat exchange elements made from metals or metal alloys from steel or ferrous alloys from stainless steel
    • 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
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
    • 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
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • 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
    • 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
    • C22C38/52—Ferrous alloys, e.g. steel alloys containing chromium with nickel with cobalt
    • 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
    • C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
    • 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
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
    • F28F21/08—Constructions of heat-exchange apparatus characterised by the selection of particular materials of metal

Definitions

  • the present invention relates to a heat exchanger for use in an evaporator in a phosphoric acid production system. More specifically, it relates to a metallic heat exchanger comprising a tube of a metallic material, said heat exchanger intended to be used in an evaporator use in a phosphoric acid production be means of the wet method. Furthermore, the present invention relates to the use of a duplex stainless steel in environments containing phosphoric acid.
  • Phosphoric acid can be produced by two different methods, commonly known as the wet method, in which phosphate ore is used to produce the phosphoric acid, and the thermal or hot method, in which elemental phosphorus is used to produce the phosphoric acid.
  • the majority of the phosphoric acid used today is produced by means of the wet method since it is less costly than the thermal process.
  • the wet method phosphoric acid is for example commonly used in fertilizer production.
  • the thermal phosphoric acid is of a much higher purity and is for example used in the manufacture of high grade chemicals, pharmaceuticals, detergents and food products.
  • the wet method comprises reacting diluted sulphuric acid (H 2 SO 4 ) with naturally occurring phosphate rock (generally consisting of calcium phosphate Ca 3 (PO 4 ) 2 ) thereby producing a calcium sulphate slurry and phosphoric acid, which are separated by filtration.
  • the acidic filtrate is recycled to the reactor to concentrate the P 2 O 5 content of the acid produced.
  • the temperature is generally between 70-90 0 C.
  • the produced crude acid is concentrated and clarified.
  • An additional step in which precipitates of sulphate arsenic and fluorosilicates are removed is often included prior to purification.
  • the corrosiveness of phosphoric acid during wet-process concentration is quite complex and is dependent on several influencing factors.
  • the factor, which has the most significant impact, is the presence of impurities.
  • impurities For example, at a given concentration, the presence of fluorides, chlorides and dilute sulfuric acid in the process will increase the corrosivity of the acid. Pure phosphoric acid is less corrosive than both sulfuric acid and hydrochloric acid.
  • standard stainless steels such as AISI 316L and 317L, are sufficient materials for construction equipment when the material is in contact with pure phosphoric acid.
  • the wet method phosphoric acid invariably contains impurities, which are derived from the phosphate rock from which the acid is produced.
  • the concentration of fluoride and chloride during the wet method varies greatly from plant to plant depending on the origin of the phosphate rock, i.e. the composition of the phosphate rock.
  • the acid also contains other ions, such as Fe 3+ , which affect the corrosion properties. Fe 3+ strongly contributes to the oxidizing potential of the acid and when present in sufficient amounts it therefore reduces corrosion of a stainless steel by facilitating the formation of a passive film on the steel surface.
  • the process media is very complex and individual. This should be taken into consideration when selecting material for a tube of the heat exchanger in the evaporator since the tube will be in direct contact with the process media.
  • the temperature can vary in the process and it is required to use the heat exchangers in the evaporator at high temperatures in order to increase the efficiency of the process.
  • This also puts high demands on corrosion resistance of a material in contact with the process media.
  • the most widely used material for heat exchanger tubes to be used in the wet method has been graphite.
  • the mechanical weakness and bhttleness of graphite is a major drawback which often resulted in repeated problems with broken tubes and thereby loss of production.
  • metallic construction of heat exchangers has become more common and a preferred solution during the last decade.
  • the most widely used metallic material for evaporator tubes in the manufacture of phosphoric acid by the wet method today is an austenitic stainless steel with the following composition in percent by weight:
  • This austenitic stainless steel is known under the standard UNS N08028.
  • UNS N08028 generally performs very well as material for evaporation tubes. However, if the life time of a tube of a heat exchanger in the evaporator could be even longer, there would be less production loss due to shut downs for changing pipes.
  • duplex stainless steel known under standard UNS S32520 is used for construction of phosphoric acid storage tanks in phosphoric acid production plants.
  • This duplex stainless steel has the following composition in percent by weight:
  • UNS S32520 has also been proposed for construction of vessels, piping, fittings and other proprietary devices in phosphoric acid production plants since it is considered to have good corrosion resistance in phosphoric acid production plant environments. To the best of the applicant's knowledge, this material has not yet been proposed as alternative material for heat exchangers but would probably be sufficient since it can be used in other parts of the plants which are exposed to similar conditions. However, a metallic material with even better corrosion resistance in the environment would probably reduce the number of shut downs for changing pipes and consequently improve production of a phosphoric acid production plant.
  • Hastelloy® G- 30 a nickel based material known under the name Hastelloy® G- 30 has been proposed for phosphoric acid environments.
  • This nickel based alloy comprises approximately max 0.03 % C, max 0.8 % Si, max 1.5 % Mn, 29.5 % Cr, max 5 % Co, 5 % Mo, 3 % W, 15 % Fe, 1.7 % Cu and 0.9 % Nb+Ti.
  • the corrosion resistance of this material is very good in the phosphoric acid environment, but G- 30 is very expensive as a result of the composition and is therefore not considered as a cost-effective material for use as heat exchanger material in a phosphoric acid production plant.
  • the object of the invention is therefore to, to a reasonable cost, improve life time of a heat exchanger for evaporation systems in phosphoric acid production systems using the wet method.
  • Impurities in the duplex stainless steel may result from the raw material used for production of the steel and/or be present in the steel as a result of the production method used. Examples of impurities are S, Al and Ca.
  • the duplex stainless steel used in accordance with the present invention has proven to have an increased corrosion resistance to environments containing phosphoric acid compared to the commonly used austenitic stainless steel UNS N08028. It is also believed that it has better corrosion resistance to the environment than UNS S32520. It has further been established that the duplex stainless steel according to the invention performs very well at temperatures at least up to 110 0 C in the intended environment. Since corrosion resistance is the most critical parameter for a tube to be used in the heat exchanger, the life time of the heat exchanger is prolonged by utilizing this duplex stainless steel.
  • duplex stainless steel is especially advantageous in phosphoric acid production systems using the wet method and wherein the process solution contains 30-80 % H 3 PO 4 , up to 2000 ppm Cl “ and up to 2 % F " .
  • the object of the present invention is related to heat exchangers to be used in the evaporation during manufacturing of phosphoric acid, it is reasonable to believe that the duplex stainless steel identified above is also suitable for use in other applications subjected to environments containing phosphoric acid.
  • Examples of such applications may for example be any application wherein phosphoric acid produced by means of the wet method is used to produce a final product as long as the duplex stainless steel described above also is suitable for use in the environment of the other components used to produce the final product and under the process conditions, such as temperature and pressure, required for the production of the final product.
  • the duplex stainless steel is considered suitable as material at least for vessels, piping, fittings and proprietary devices in phosphoric acid production plants.
  • the duplex stainless steel may also be used as construction material in fertilizer production plants for parts in contact with phosphoric acid containing media.
  • Figure 1 shows the result of a corrosion test in phosphoric acid with three different concentrations.
  • Figure 2 shows the iso-corrosion curve for 0.1 mm/year of the duplex stainless steel used according to the invention.
  • Figure 3 shows the temperature dependence on the corrosion rate of the duplex stainless steel used according to the invention.
  • the duplex stainless steel used according to the present invention has the following composition in percent by weight: C max 0.03
  • the duplex stainless steel has a ferrite content of 40-65 %. Furthermore, it has a well balanced composition such that both the ferrite and the austenite phase have high corrosion resistance as a result of the alloying elements being well distributed between the two phases.
  • the PREW value of the alloy is at least 45, wherein PREW is [wt-%Cr]+3.3([wt-%Mo]+0.5[wt-%W])+16[wt-%N].
  • the PREW value of each phase i.e. ferrite and austenite, is at least 45. More preferably, the relationship [PREW aus t ⁇ n ⁇ t ⁇ ]/[PREf ⁇ rr ⁇ t ⁇ ] is 0.9-1.15.
  • the duplex stainless steel comprises max 1.2 % Cu.
  • the duplex stainless steel comprises 0.5-3.5 % Co.
  • the duplex stainless steel comprises 26.5-28 % Cr.
  • the proof strength and tensile strength, when in the form of a solution annealed seamless tube, of the duplex stainless steel used according to the present invention is listed in Table 1. These figures can for example be compared to UNS N08028 which has a minimum tensile strength at 100 0 C of 510 MPa when in the form of a seamless tube. Clearly the mechanical strength of the duplex stainless steel used according to the present invention is much higher than the conventionally used UNS N08028.
  • the duplex stainless steel has the following nominal composition in percent by weight:
  • Test samples in the form of tube-halves were produced from steels with the following composition in percent by weight: C 0.013
  • Test samples in the form of tube halves were produced of an alloy with the following composition in percent by weight:
  • duplex stainless steel according to the present invention has a good resistance to phosphoric acid in different chloride and fluoride concentrations. Table 3.
  • Example 3 Test samples in the form of tube halves were produced of an alloy with the following composition:
  • Test samples in the form of tube halves were produced of an alloy with the following composition:
  • test samples of the alloy UNS N08028 in the form of tube halves were tested for comparison.
  • the temperature dependence of the general corrosion in synthetic phosphoric acid was investigated in the temperature range 80-1 10°C.
  • the acid had the following composition:
  • Test samples in the form of tube-halves were produced from steels with the following composition in percent by weight:
  • the general corrosion test according to ASTM G 31 -72 rev 2004, was performed at a temperature of 90 0 C using a duration of 1 +3+3 days.
  • the phosphoric acid used had the following composition: H 3 PO 4 -58 %
  • UNS N08028 had a mean corrosion rate of 0.0626 mm/year and UNS S32520 had a mean corrosion rate of 0.0730 mm/year. From this test it is clear that UNS S32520 corrodes much faster than UNS N08028 and thus has a shorter service life in phosphoric acid environments containing impurities.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Thermal Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Rigid Pipes And Flexible Pipes (AREA)
  • Heat Treatment Of Articles (AREA)
  • Heat Treatment Of Steel (AREA)
  • Heat Treatment Of Sheet Steel (AREA)

Abstract

La présente invention porte sur l'utilisation d'un acier inoxydable duplex en tant que matériau d'échange de chaleur dans un système de production d'acide phosphorique utilisant le procédé par voie humide. L'acier a la composition suivante en pourcentages en poids : 0,03 max de C, 0,5 max de Si, 3 max de Mn, 26 à 29 de Cr, 4,9 à 10 de Ni, 3 à 5 de Mo, 0,35 à 0,5 de N, 0,0030 max de B, 3,5 max de Co, 3 max de W, 2 max de Cu, 0,3 max de Ru, le reste étant constitué par Fe et des impuretés apparaissant normalement.
EP08841210A 2007-10-26 2008-10-24 Utilisation d'un acier inoxydable duplex dans un système de production d'acide phosphorique Withdrawn EP2215421A4 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE0702392A SE531593C2 (sv) 2007-10-26 2007-10-26 Värmeväxlare för fosforsyramiljö
PCT/SE2008/051204 WO2009054799A1 (fr) 2007-10-26 2008-10-24 Utilisation d'un acier inoxydable duplex dans un système de production d'acide phosphorique

Publications (2)

Publication Number Publication Date
EP2215421A1 true EP2215421A1 (fr) 2010-08-11
EP2215421A4 EP2215421A4 (fr) 2010-10-06

Family

ID=40579783

Family Applications (1)

Application Number Title Priority Date Filing Date
EP08841210A Withdrawn EP2215421A4 (fr) 2007-10-26 2008-10-24 Utilisation d'un acier inoxydable duplex dans un système de production d'acide phosphorique

Country Status (4)

Country Link
US (1) US20100294472A1 (fr)
EP (1) EP2215421A4 (fr)
SE (1) SE531593C2 (fr)
WO (1) WO2009054799A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2746285C (fr) * 2011-03-31 2018-01-23 Nova Chemicals Corporation Ailettes de serpentin d'appareil de chauffage

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3338745A (en) * 1963-07-03 1967-08-29 Grace W R & Co Method for cleaning evaporator tubes
US20030086808A1 (en) * 2001-09-02 2003-05-08 Ann Sundstrom Duplex stainless steel alloy
US20030133823A1 (en) * 2001-09-02 2003-07-17 Ann Sundstrom Use of a duplex stainless steel alloy

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU296446A1 (ru) * 1966-08-04 1972-01-07 Центральный научно исследовательский институт черной металлургии Нержавеющая сталь
JPH03146641A (ja) * 1989-11-01 1991-06-21 Taiheiyo Tokushu Chuzo Kk 湿式りん酸製造装置用二相ステンレス鋳鋼
AT397515B (de) * 1990-05-03 1994-04-25 Boehler Edelstahl Hochfeste korrosionsbeständige duplex-legierung
KR100704201B1 (ko) * 2003-06-30 2007-04-09 수미도모 메탈 인더스트리즈, 리미티드 2상 스테인리스강
US7396421B2 (en) * 2003-08-07 2008-07-08 Sumitomo Metal Industries, Ltd. Duplex stainless steel and manufacturing method thereof

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3338745A (en) * 1963-07-03 1967-08-29 Grace W R & Co Method for cleaning evaporator tubes
US20030086808A1 (en) * 2001-09-02 2003-05-08 Ann Sundstrom Duplex stainless steel alloy
US20030133823A1 (en) * 2001-09-02 2003-07-17 Ann Sundstrom Use of a duplex stainless steel alloy

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO2009054799A1 *

Also Published As

Publication number Publication date
EP2215421A4 (fr) 2010-10-06
SE0702392L (sv) 2009-04-27
US20100294472A1 (en) 2010-11-25
WO2009054799A1 (fr) 2009-04-30
SE531593C2 (sv) 2009-06-02

Similar Documents

Publication Publication Date Title
CA2165817C (fr) Acier inoxydable ferritique-austenitique; utilisation de l'acier
US10407759B2 (en) Cost reduced steel for hydrogen technology with high resistance to hydrogen-induced embrittlement
JP3355510B2 (ja) オーステナイト合金およびそれらの使用
EP2930254B1 (fr) Plaque d'acier plaqué inoxydable dotée d'une excellente résistance à la corrosion dans l'eau de mer
TW201742932A (zh) 高強度抗腐蝕沃斯田合金
CN111868278A (zh) 耐腐蚀的双相不锈钢
CN111511943B (zh) 双相不锈钢及其用途
CN116179947A (zh) 双相不锈钢及其成型物
CN103215513A (zh) 一种抗腐蚀集输管线管及其制造方法
US10207477B2 (en) Stainless steel clad steel plate including cladding material for stainless steel clad steel plate and method of manufacturing the same
CA2817022A1 (fr) Alliage de nickel-chrome-fer-molybdene
EP2215421A1 (fr) Utilisation d'un acier inoxydable duplex dans un système de production d'acide phosphorique
US5723089A (en) Line pipe metal arc welded with wire alloy
US20170275737A1 (en) Metallic nickel-based acid-resistant material
RU2782563C2 (ru) Дуплексные нержавеющие стали и их применения
US4252561A (en) Chromium-alloyed steel which is corrosion resistant to caustic alkaline solution
JPS6199656A (ja) ラインパイプ用高強度溶接鋼管
JPH0357181B2 (fr)
Bernhardsson Corrosion performance of a high-nickel alloy
JPS63213633A (ja) ラインパイプ用高耐食クラツド鋼管
CN102534412B (zh) 一种高压锅炉用耐腐蚀钢管
US20020009382A1 (en) Stainless alloys for enhanced corrosion resistance
Sugahara A Ni-45Cr-1Mo alloy for industrial cleaning agents such as a mixture of nitric and hydrofluoric acids
CA1115093A (fr) Articles soudes en acier inoxydable ferritique
JPH02274841A (ja) 硫化物環境において溶接熱影響部の耐食性に優れた２相ステンレス鋼

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20100526

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL BA MK RS

A4 Supplementary search report drawn up and despatched

Effective date: 20100907

17Q First examination report despatched

Effective date: 20100920

DAX Request for extension of the european patent (deleted)
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20160607