Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C273/00—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
  • C07C273/02—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of urea, its salts, complexes or addition compounds
  • C07C273/04—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of urea, its salts, complexes or addition compounds from carbon dioxide and ammonia
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C9/00—Alloys based on copper
  • C22C9/01—Alloys based on copper with aluminium as the next major constituent
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/141—Feedstock

Definitions

• the present invention which is based upon the results of applicants researches, relates to materials employed in the construction of apparatus used in the synthetic manufacture of urea.
• the present invention makes it possible to carry out the production. of. urea with only insignificant corrosion, by the use of certain alloys of copper with aluminum.
• the parts of apparatus which are subjected to the attack by hot mixtures of urea-ammonium carbamate-water, are made of or are. protected with. alloys of special composition belonging to the so-called aluminum bronze group-of alloys.
• alloys of special composition belonging to the so-called aluminum bronze group-of alloys.
• copper alloys having 3 to 11% aluminum and, eventually, slight amounts of other metals such,v as Fe, Mn, Ni, Si, V, Cr, Pb, Ti, etc., the sum of which does not exceed 5%.
• aluminum bronzes possessgood, mechanical characteristics, and are easily workable, they are used, according to the present invention, in the construction of the apparatus themselves, such as autoclaves, inlet pipes for CO and NH3, or any other pipes or parts terminatingv atthe autoclave or situated inside thereof, as well as in the manufacture of protecting linings for walls made or other metals.
• the apparatus or parts thereof used in the synthesis of urea are madewith' the view of enhancing their resistance to corrosion-of aluminum bronze which contains manganese, and which hasan iron content lower than that of themanganese.
• the bronzeaccordiug to the invention should contain 0.1 to 4% Mn, while its iron content should not exceed that of the manganese.
• the alloy is composed, in addition to copper, of 8 to 10%- A1, 0.2 to 1% Mn, 0.02 to 0.4% Fe and less than 0.3% other elements, while the ratio- Percent Fe Percent Mn does not exceed 0.5.
• said other elements should be, for example, Cr, V, Ti and/ or, especially, Si.
• the aluminum bronze should be both poor in iron and that the ratio iron/ manganese below.
• commercial aluminum bronzes generally contain more than 0.5% Feand, most often, even more than 1%.; when-they contain manganese, the content of this element is lower than that of Fe.
• most of commercial alloys have 1 to 4.25% Fe and those which also contain Mn, have less than 1.5% of the latter as against 2 to. 3.5% Fe.
• reference ismade to the followingtable which is reproduced from an article entitled: Aluminum Bronze by John L. Everhart, Materials, and Methods, December 1952, vol. 36, #6, pp. 119434, constituting-v Table I found at page 122 thereof.
• the ratio Percent Fe Percent Mn preferably ranging between 0.1 and 0.45. These alloys may preferably contain 0.01 to 0.1% Si, this silicon being partially or completely replaceable by V, Cr or Ti. Alloys within this range have a loss by corrosion in the presence of urea amounting to less than 100 grs. per square metre per year.
• aluminum bronzes are characterized by a critical relationship of the proportions of the constituents used, particularly, as regards the actual and relative proportions of Fe and Mn, when both of these are used in formulating the alloy.
• the resultant product possesses to an exceptional degree resistance to corrosion when in presence of a hot-urea-ammonium carbamatewater mixture.
• the preferred alloys of applicants invention i. e. those possessing the most outstanding characteristics as regards resistance to corrosion, contain both Fe and Mn within the proportions specified.
• aluminum bronzes which are free of manganese, but which have a very low iron content, also possess valuable properties as regards resistance to corrosion. This is particularly true of a bronze-identified as bronze A on the table set out belowhaving the following composition:
• Norm-Minus sign indicates loss of weight; plus sign indicates gain of weight.
• Apparatus for use in the synthesis of urea from ammonia and carbon dioxide characterized in that the parts of the apparatus in contact with the hot reaction medium are formed of aluminum bronze, containing Percent Aluminum 8 to 10 Manganese 0.2 to 1 Iron 0.02 to 0.4 Constituents other than copper less than 0.3
• the ratio of iron to manganese being less than 0.5.
• Apparatus according to claim 1 which includes silicon as one of said constituents.
• Apparatus for use in the synthesis of urea from ammonia and carbon dioxide characterized in that the parts of the apparatus in contact with the hot reaction medium are formed of aluminum bronze, containing Percent Aluminum 9 to 10 Manganese 0.2 to 0.6 Iron 0.05 to 0.25
• the ratio of iron to manganese ranging from 0.1 to 0.45.
• parts of the apparatus in contact with the hot reaction medium are formed of aluminum bronze, which consists of (24th ed., 1940), page 1237.

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

Applications Claiming Priority (1)

Publications (1)

Family

ID=9487533

Family Applications (1)

Country Status (4)

Cited By (8)

Citations (2)

Family Cites Families (1)

• 1952
  • 1952-12-13 FR FR1068305D patent/FR1068305A/fr not_active Expired
• 1953
  • 1953-12-07 US US396729A patent/US2778733A/en not_active Expired - Lifetime
  • 1953-12-11 GB GB34595/53A patent/GB787504A/en not_active Expired
  • 1953-12-12 DE DEP10983A patent/DE954243C/de not_active Expired

Patent Citations (2)

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