US3353995A - Removal of ferrous sulfide deposits - Google Patents
Removal of ferrous sulfide deposits Download PDFInfo
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- US3353995A US3353995A US355113A US35511364A US3353995A US 3353995 A US3353995 A US 3353995A US 355113 A US355113 A US 355113A US 35511364 A US35511364 A US 35511364A US 3353995 A US3353995 A US 3353995A
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- thiourea
- weight
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- ferrous
- ferrous sulfide
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- MBMLMWLHJBBADN-UHFFFAOYSA-N Ferrous sulfide Chemical compound [Fe]=S MBMLMWLHJBBADN-UHFFFAOYSA-N 0.000 title claims description 41
- UMGDCJDMYOKAJW-UHFFFAOYSA-N aminothiocarboxamide Natural products NC(N)=S UMGDCJDMYOKAJW-UHFFFAOYSA-N 0.000 claims description 62
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Natural products NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 36
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims description 28
- JPVYNHNXODAKFH-UHFFFAOYSA-N Cu2+ Chemical compound [Cu+2] JPVYNHNXODAKFH-UHFFFAOYSA-N 0.000 claims description 27
- 229910001431 copper ion Inorganic materials 0.000 claims description 27
- 239000002184 metal Substances 0.000 claims description 24
- 229910052751 metal Inorganic materials 0.000 claims description 24
- 239000007864 aqueous solution Substances 0.000 claims description 21
- 238000000034 method Methods 0.000 claims description 17
- -1 THIOUREA COMPOUND Chemical class 0.000 claims description 10
- HTKFORQRBXIQHD-UHFFFAOYSA-N allylthiourea Chemical compound NC(=S)NCC=C HTKFORQRBXIQHD-UHFFFAOYSA-N 0.000 claims description 10
- 229960001748 allylthiourea Drugs 0.000 claims description 10
- KREOCUNMMFZOOS-UHFFFAOYSA-N 1,3-di(propan-2-yl)thiourea Chemical compound CC(C)NC(S)=NC(C)C KREOCUNMMFZOOS-UHFFFAOYSA-N 0.000 claims description 8
- FLVIGYVXZHLUHP-UHFFFAOYSA-N N,N'-diethylthiourea Chemical compound CCNC(=S)NCC FLVIGYVXZHLUHP-UHFFFAOYSA-N 0.000 claims description 8
- PDQAZBWRQCGBEV-UHFFFAOYSA-N Ethylenethiourea Chemical compound S=C1NCCN1 PDQAZBWRQCGBEV-UHFFFAOYSA-N 0.000 claims description 7
- VLCDUOXHFNUCKK-UHFFFAOYSA-N N,N'-Dimethylthiourea Chemical compound CNC(=S)NC VLCDUOXHFNUCKK-UHFFFAOYSA-N 0.000 claims description 7
- 239000002253 acid Substances 0.000 claims description 6
- 150000007513 acids Chemical class 0.000 claims description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 21
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 20
- 239000000243 solution Substances 0.000 description 8
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 6
- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 6
- 239000010949 copper Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000003208 petroleum Substances 0.000 description 4
- 238000011282 treatment Methods 0.000 description 4
- 150000001879 copper Chemical class 0.000 description 3
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical compound [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 229910000365 copper sulfate Inorganic materials 0.000 description 2
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 2
- OPQARKPSCNTWTJ-UHFFFAOYSA-L copper(ii) acetate Chemical compound [Cu+2].CC([O-])=O.CC([O-])=O OPQARKPSCNTWTJ-UHFFFAOYSA-L 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 239000011593 sulfur Substances 0.000 description 2
- 150000003585 thioureas Chemical class 0.000 description 2
- 229910021591 Copper(I) chloride Inorganic materials 0.000 description 1
- 230000001154 acute effect Effects 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- OXBLHERUFWYNTN-UHFFFAOYSA-M copper(I) chloride Chemical compound [Cu]Cl OXBLHERUFWYNTN-UHFFFAOYSA-M 0.000 description 1
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Substances Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 description 1
- 229940076286 cupric acetate Drugs 0.000 description 1
- 229960003280 cupric chloride Drugs 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- ALYDDXONYRLFSU-UHFFFAOYSA-N ethene;thiourea Chemical compound C=C.NC(N)=S ALYDDXONYRLFSU-UHFFFAOYSA-N 0.000 description 1
- IXCSERBJSXMMFS-UHFFFAOYSA-N hcl hcl Chemical compound Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
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
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
- C23G1/08—Iron or steel
Definitions
- This invention relates to a method of removing ferrous sulfide deposits from ferrous metal surfaces, and more particularly to a method for removing such deposits with dr ic acid or sulfuric acid whereby the presence of free hydrogen sulfide is substantially minimized.
- ferrous sulfide In many processes involving sulfur, deposits including ferrous sulfide (FeS) tend to build upon ferrous metal surfaces such as reactor walls, p ipipg, etc. Petroleum processing presents a particularly acute problem when sulfur is removed from the petroleum in a desulfurizer. Deposits of coke containing as much as 80 percent ferrous sulfide may accumulate. Since hydrochloric acid (HCl) and sulfuric acid (H 50 generally react with the ferrous sulfide to produce hydrogen sulfide (H 5) which is extremely toxic and generally very corrosive to ward materials commonly used in construction, sulfuric acid and hydrochloric acid, although readily available, economic materials, are seldom used to remove ferrous sulfide-containing deposits from such metal surfaces.
- HCl hydrochloric acid
- sulfuric acid H 50 generally react with the ferrous sulfide to produce hydrogen sulfide (H 5) which is extremely toxic and generally very corrosive to ward materials commonly used in construction,
- a common method of removing ferrous sulfide-containing deposits is to subject the deposit-supporting ferrous material to high temperatures in the presence of oxygen. Such methods are usually costly and are inherently dangerous to the ferrous material of construction.
- an aqueous solution. containing from about 1 to about percent by weight sulfuric Q1 hydrochloric agigl, a soluble ggpper salt, copper ion being present in an amount of from about 0.1 to about 1.0 percent by weight and an amount of a thiourea compound equivalent to thiourea in an amount of from about 2 to about times the weight of copper ion present is employed to treat a ferrous metal surface which is contaminated by a ferrous sulfide-containing deposit, thereby to react with the ferrous sulfide-containing deposit and safely remove said ferrous sulfide without the presence of substantially any free hydrogen sulfide.
- Copper ion is usually introduced to the solution by dissolving a suitable copper salt therein.
- suitable copper salts are those having anions which do not form interfering byproducts during treatment.
- Appropriate soluble copper salts for use in the present invention are: copper sulfate (CuSO cupric nitrate (Cu(NO cupric acetate (Cu(C I-l O- cupric chloride (CuCl and the like.
- thiourea compounds for use in the present invention are: thiourea, 1,3-dimethyl thiourea, 1,3-
- 1,3-dimethyl thiourea, 1,3-diethyl thiourea, allyl thiourea, ethylene thiourea, or 1,3-diisopropyl thiourea are substituied for thiourea, such substitution should be made in approximately equimolar amounts based on the desired concentration of thiourea.
- hydrochloric acid When hydrochloric acid is employed, it is generally present in concentrations of from about 1 to about 10 percent by weight, with concentrations of from about 2 to about 5 percent by weight being preferred. Concentration of copper ion, when hydrochloric acid is employed, is generally from about 0.2 to about 1.0 percent by weight, with copper ion concentrations of from about 0.5 to about 1.0 percent by weight being preferred. Thiourea, when hydrochloric acid is employed, is generally present in an amount of from about 2 to about 10 times the weight of copper ion present, and preferably in a concentration of from about 2 to about 5 times the weight of copper ion.
- sulfuric acid When sulfuric acid is employed, it is generally present in concentrations of from about 1 to about 5 percent by weight, with concentrations of from about 3 to about 5 percent by weight being preferred. Copper ion, when sulfuric acid is employed, is generally present in an amount of from about 0.1 to about 0.5 percent by weight, with concentrations of from about 0.2 to about 0.5 percent by weight being preferred. Thiourea, when sulfuric acid is employed, is generally present in an amount of from about 10 to about 20 times the weight of copper ion present, and preferably from about 10 to about 16 times the weight of copper present.
- treatment is carried out by contacting the surface to be treated with solution at ambient temperatures, although the solution may be warmed to facilitate dissolution of ferrous sulfide, if desired.
- Extreme high temperatures i.e., near the boiling point of the solution, however, should be avoided since the presence of free hydrogen sulfide is more likely during such high temperature treatments, and the likelihood of copper plating of the ferrous metal surface is also increased.
- the treatment is advantageously carried out under pressure in excess of atmospheric. Pressure is not, however, required for operability of the present invention.
- Example 1 Furthermore, the expected precipitate of Cu S or Cus did not form.
- Example 2 An aqueous solution was prepared containing 5 percent by weight HCl, 0.5 percent by weight of copper ion, and 2 percent by weight of thiourea. To the solution at ambient temperature was added a known amount of FeS. Substantially the same results were obtained as described hereinbefore in Example 1.
- Example 3 In substantially the same manner as described in Examples 1 and 2, allyl thiourea, 1,3-dimethyl thiourea, 1,3- diethyl thiourea, ethylene thiourea, and 1,3-diisopropyl thiourea may be substituted, on an equimolar basis, for the thiourea employed therein, with substantially the same results.
- Example 4 An aqueous solution containing 5 percent by weight sulfuric acid, copper sulfate in an amount equivalent to 0.4 percent by weight copper ion, and 9.6 weight percent allyl thiourea (equivalent to 6.3 weight percent thiourea). FeS added to the solution dissolved with no noticeable amounts of free H 8 being given off and no precipitate formed.
- Example 5 t/ In substantially the same manner as described in Example 4, thiourea, 1,3-dimethyl thiourea, 1,3-diethyl thiourea, ethylene thiourea, and 1,3-diisopropyl thiourea may be substituted, on equimolar basis, for the allyl thiourea employed therein, with substantially the jame results.
- Example 6 An aqueous solution containing about five percent by weight hydrochloric acid, about 0.5 percent by weight copper ions, and about 4 percent by weight thiourea was employed to remove ferrous sulfide from the interior surface of a ferrous metal pipe employed in a petroleum process. Removal of ferrous sulfide was readily accomplished by simple contact of the solution with the ferrous sulfide deposit the pipe. Substantially no free hydrogen sulfide was given off.
- a method of removing ferrous sulfide from ferrous metal surfaces comprising providing an aqueous solution containing from about one to about ten percent by weight of an acid selected from the group consisting of hydrochloric and sulfuric acids, from about 0.1 to about 1.0 percent by weight of copper ion, and a thiourea compound selected from the group consisting of thiourea, 1,3- dimethyl thiourea, 1,3-diethyl thiourea, allyl thiourea, ethylene thiourea, and 1,3-diisopropyl thiourea, said thiourea compound being present in an amount equivalent to an amount of thiourea from about 2 to about 20 times the weight of copper ion present, and contacting the ferrous sulfide-containing ferrous metal surface with said aqueous solution, thereby to remove ferrous sulfide.
- a method of removing ferrous sulfide from ferrous metal surfaces comprising providing an aqueous solution containing from about one to about ten percent by weight of hydrochloric acid, from about 0.2 to about 1.0 percent tron containing about five percent by weight sulfuric V by weight of copper ion, and a thiourea compound selected from the group consisting of thiourea, 1,3-dimethy1 thiourea, 1,3-diethyl thiourea, allyl thiourea, ethylene thiourea, and 1,3-diisopropyl thiourea, said thiourea compound being present in an amount equivalent to an amount of thiourea from about 2 to about 10 times the weight of copper ion present, and contacting the ferrous sulfide-containing ferrous metal surface with said aqueous solution, thereby to remove ferrous sulfide.
- a method of removing ferrous sulfide from ferrous metal surfaces comprising providing an aqueous solution containing from about one to about five percent by weight sulfuric acid, from about 0.1 to about 0.5 percent by weight of copper ion, and a thiourea compound selected from the group consisting of thiourea, 1,3-dimethyl thiourea, 1,3-diethyl thiourea, allyl thiourea, ethylene thiourea, and 1,3-diisopropyl thiourea, said thiourea compound being present in an amount equivalent to an amount of thiourea from about 10 to about 20 times the weight of copper ion present, and contacting the ferrous sulfide-containing ferrous metal surface with said aqueous solution, thereby to remove ferrous sulfide.
- a method of removing ferrous sulfide from ferrous metal surfaces comprising providing an aqueous solution containing about five percent by weight of hydrochloric acid, 0.5 percent by weight of copper ion, and about 2 percent by weight of thiourea, and contacting the ferrous sulfide-containing ferrous metal surface with said aqueous solution, thereby to remove ferrous sulfide.
- a method of removing ferrous sulfide from ferrous metal surfaces comprising providing an aqueous solution containing about five percent by weight of hydrochloric acid, 0.5 percent by weight of copper ion, and about 4 percent by weight of thiourea, and contacting the ferrous sulfide-containing ferrous metal surface with said aqueous solution, thereby to remove ferrous sulfide.
- a method of removing ferrous sulfide from ferrous metal surfaces comprising providing an aqueous solution containing about five percent by weight sulfuric acid, 0.4 percent by weight of copper ion, and about 9.6 percent by weight of allyl thiourea and contacting the ferrous sulfidecontaining ferrous metal surface with said aqueous solution, thereby to remove ferrous sulfide.
- a method of removing ferrous sulfide from ferrous metal surfaces comprising providing an aqueous solution containing about five percent by weight sulfuric acid, 0.4 percent by weight of copper ion, and about 6 percent by weight of thiourea and contacting the ferrous sulfidecontaining ferrous metal surface with said aqueous solution, thereby to remove ferrous sulfide.
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Description
HJQ
United States Patent 3,353,995 REMOVAL OF FERROUS SULFIDE DEPOSITS Fred Norman Teumac, Lake Jackson, Tex., assignor to The Dow Chemical Company, Midland, Mich., a corporation of Delaware No Drawing. Filed Mar. 26, 1964, Ser. No. 355,113 7 Claims. (Cl. 134-3) ABSTRACT OF THE DISCLOSURE This invention relates to an improved process for removing ferrous sulfide from ferrous metal surfaces by contacting such surfaces with a dilute (ll0%) aqueous solution of a strong mineral acid such as HCl or H 50 containing from about 0.1 to about 1.0 weight percent of copper ion and from 2 to 20 times the weight of such copper ions of a thiourea compound.
This invention relates to a method of removing ferrous sulfide deposits from ferrous metal surfaces, and more particularly to a method for removing such deposits with dr ic acid or sulfuric acid whereby the presence of free hydrogen sulfide is substantially minimized.
In many processes involving sulfur, deposits including ferrous sulfide (FeS) tend to build upon ferrous metal surfaces such as reactor walls, p ipipg, etc. Petroleum processing presents a particularly acute problem when sulfur is removed from the petroleum in a desulfurizer. Deposits of coke containing as much as 80 percent ferrous sulfide may accumulate. Since hydrochloric acid (HCl) and sulfuric acid (H 50 generally react with the ferrous sulfide to produce hydrogen sulfide (H 5) which is extremely toxic and generally very corrosive to ward materials commonly used in construction, sulfuric acid and hydrochloric acid, although readily available, economic materials, are seldom used to remove ferrous sulfide-containing deposits from such metal surfaces.
A common method of removing ferrous sulfide-containing deposits is to subject the deposit-supporting ferrous material to high temperatures in the presence of oxygen. Such methods are usually costly and are inherently dangerous to the ferrous material of construction.
I have discovered a method whereby unexpectedly, ferrous sulfide is safely removed from ferrous metal surfaces by means of dilute strong mineral acids without the presence of significant amounts of free hydrogen sulfide.
In accordance with the present invention, an aqueous solution. containing from about 1 to about percent by weight sulfuric Q1 hydrochloric agigl, a soluble ggpper salt, copper ion being present in an amount of from about 0.1 to about 1.0 percent by weight and an amount of a thiourea compound equivalent to thiourea in an amount of from about 2 to about times the weight of copper ion present is employed to treat a ferrous metal surface which is contaminated by a ferrous sulfide-containing deposit, thereby to react with the ferrous sulfide-containing deposit and safely remove said ferrous sulfide without the presence of substantially any free hydrogen sulfide.
Copper ion is usually introduced to the solution by dissolving a suitable copper salt therein. Suitable copper salts are those having anions which do not form interfering byproducts during treatment. Appropriate soluble copper salts for use in the present invention are: copper sulfate (CuSO cupric nitrate (Cu(NO cupric acetate (Cu(C I-l O- cupric chloride (CuCl and the like.
Appropriate thiourea compounds for use in the present invention are: thiourea, 1,3-dimethyl thiourea, 1,3-
"ice
diethyl thiourea, allyl thiourea, ethylene thiourea, and 1,3-diisopropyl thiourea. For clarity in expressing suitable solution composition and concentrations, all such references made herein will be based on thiourea. Quantities of the substituted thiourea compounds, therefore, will be expressed as the thiourea equivalent. To illustrate, when 1,3-dimethyl thiourea, 1,3-diethyl thiourea, allyl thiourea, ethylene thiourea, or 1,3-diisopropyl thiourea are substituied for thiourea, such substitution should be made in approximately equimolar amounts based on the desired concentration of thiourea.
When hydrochloric acid is employed, it is generally present in concentrations of from about 1 to about 10 percent by weight, with concentrations of from about 2 to about 5 percent by weight being preferred. Concentration of copper ion, when hydrochloric acid is employed, is generally from about 0.2 to about 1.0 percent by weight, with copper ion concentrations of from about 0.5 to about 1.0 percent by weight being preferred. Thiourea, when hydrochloric acid is employed, is generally present in an amount of from about 2 to about 10 times the weight of copper ion present, and preferably in a concentration of from about 2 to about 5 times the weight of copper ion.
When sulfuric acid is employed, it is generally present in concentrations of from about 1 to about 5 percent by weight, with concentrations of from about 3 to about 5 percent by weight being preferred. Copper ion, when sulfuric acid is employed, is generally present in an amount of from about 0.1 to about 0.5 percent by weight, with concentrations of from about 0.2 to about 0.5 percent by weight being preferred. Thiourea, when sulfuric acid is employed, is generally present in an amount of from about 10 to about 20 times the weight of copper ion present, and preferably from about 10 to about 16 times the weight of copper present.
Generally, treatment is carried out by contacting the surface to be treated with solution at ambient temperatures, although the solution may be warmed to facilitate dissolution of ferrous sulfide, if desired. Extreme high temperatures, i.e., near the boiling point of the solution, however, should be avoided since the presence of free hydrogen sulfide is more likely during such high temperature treatments, and the likelihood of copper plating of the ferrous metal surface is also increased.
Where operating conditions permit, the treatment is advantageously carried out under pressure in excess of atmospheric. Pressure is not, however, required for operability of the present invention.
A better understanding of the present invention may be obtained in light of the following examples which are set forth to illustrate, and are not to be construed to limit, the present invention.
Example 1 Furthermore, the expected precipitate of Cu S or Cus did not form.
Example 2 An aqueous solution was prepared containing 5 percent by weight HCl, 0.5 percent by weight of copper ion, and 2 percent by weight of thiourea. To the solution at ambient temperature was added a known amount of FeS. Substantially the same results were obtained as described hereinbefore in Example 1.
Example 3 In substantially the same manner as described in Examples 1 and 2, allyl thiourea, 1,3-dimethyl thiourea, 1,3- diethyl thiourea, ethylene thiourea, and 1,3-diisopropyl thiourea may be substituted, on an equimolar basis, for the thiourea employed therein, with substantially the same results.
Example 4 An aqueous solution containing 5 percent by weight sulfuric acid, copper sulfate in an amount equivalent to 0.4 percent by weight copper ion, and 9.6 weight percent allyl thiourea (equivalent to 6.3 weight percent thiourea). FeS added to the solution dissolved with no noticeable amounts of free H 8 being given off and no precipitate formed.
Example 5 t/ In substantially the same manner as described in Example 4, thiourea, 1,3-dimethyl thiourea, 1,3-diethyl thiourea, ethylene thiourea, and 1,3-diisopropyl thiourea may be substituted, on equimolar basis, for the allyl thiourea employed therein, with substantially the jame results.
Example 6 An aqueous solution containing about five percent by weight hydrochloric acid, about 0.5 percent by weight copper ions, and about 4 percent by weight thiourea was employed to remove ferrous sulfide from the interior surface of a ferrous metal pipe employed in a petroleum process. Removal of ferrous sulfide was readily accomplished by simple contact of the solution with the ferrous sulfide deposit the pipe. Substantially no free hydrogen sulfide was given off.
Substantially the same results were obtained when ferrous sulfide deposits were removed from petroleum process mby contacting the deposits with an aqueous soluacid, about 0.4 percent by weight copper ion, and about 6 percent by weight thiourea.
Various modifications may be made in the present invention without departing from the spirit or scope thereof, and it is to be understood that I limit myself only as defined in the appended claims.
I claim:
1. A method of removing ferrous sulfide from ferrous metal surfaces comprising providing an aqueous solution containing from about one to about ten percent by weight of an acid selected from the group consisting of hydrochloric and sulfuric acids, from about 0.1 to about 1.0 percent by weight of copper ion, and a thiourea compound selected from the group consisting of thiourea, 1,3- dimethyl thiourea, 1,3-diethyl thiourea, allyl thiourea, ethylene thiourea, and 1,3-diisopropyl thiourea, said thiourea compound being present in an amount equivalent to an amount of thiourea from about 2 to about 20 times the weight of copper ion present, and contacting the ferrous sulfide-containing ferrous metal surface with said aqueous solution, thereby to remove ferrous sulfide.
2. A method of removing ferrous sulfide from ferrous metal surfaces comprising providing an aqueous solution containing from about one to about ten percent by weight of hydrochloric acid, from about 0.2 to about 1.0 percent tron containing about five percent by weight sulfuric V by weight of copper ion, and a thiourea compound selected from the group consisting of thiourea, 1,3-dimethy1 thiourea, 1,3-diethyl thiourea, allyl thiourea, ethylene thiourea, and 1,3-diisopropyl thiourea, said thiourea compound being present in an amount equivalent to an amount of thiourea from about 2 to about 10 times the weight of copper ion present, and contacting the ferrous sulfide-containing ferrous metal surface with said aqueous solution, thereby to remove ferrous sulfide.
3. A method of removing ferrous sulfide from ferrous metal surfaces comprising providing an aqueous solution containing from about one to about five percent by weight sulfuric acid, from about 0.1 to about 0.5 percent by weight of copper ion, and a thiourea compound selected from the group consisting of thiourea, 1,3-dimethyl thiourea, 1,3-diethyl thiourea, allyl thiourea, ethylene thiourea, and 1,3-diisopropyl thiourea, said thiourea compound being present in an amount equivalent to an amount of thiourea from about 10 to about 20 times the weight of copper ion present, and contacting the ferrous sulfide-containing ferrous metal surface with said aqueous solution, thereby to remove ferrous sulfide.
4. A method of removing ferrous sulfide from ferrous metal surfaces comprising providing an aqueous solution containing about five percent by weight of hydrochloric acid, 0.5 percent by weight of copper ion, and about 2 percent by weight of thiourea, and contacting the ferrous sulfide-containing ferrous metal surface with said aqueous solution, thereby to remove ferrous sulfide.
5. A method of removing ferrous sulfide from ferrous metal surfaces comprising providing an aqueous solution containing about five percent by weight of hydrochloric acid, 0.5 percent by weight of copper ion, and about 4 percent by weight of thiourea, and contacting the ferrous sulfide-containing ferrous metal surface with said aqueous solution, thereby to remove ferrous sulfide.
6. A method of removing ferrous sulfide from ferrous metal surfaces comprising providing an aqueous solution containing about five percent by weight sulfuric acid, 0.4 percent by weight of copper ion, and about 9.6 percent by weight of allyl thiourea and contacting the ferrous sulfidecontaining ferrous metal surface with said aqueous solution, thereby to remove ferrous sulfide.
7. A method of removing ferrous sulfide from ferrous metal surfaces comprising providing an aqueous solution containing about five percent by weight sulfuric acid, 0.4 percent by weight of copper ion, and about 6 percent by weight of thiourea and contacting the ferrous sulfidecontaining ferrous metal surface with said aqueous solution, thereby to remove ferrous sulfide.
References Cited UNITED STATES PATENTS 2,049,517 8/1936 Saukaitis 134-4l 2,388,302 11/1945 Weyl 1343 XR 2,662,042 12/1953 Dougherty et a1 134-22 2,959,555 11/1960 Martin et a1. 134-3 XR JOSEPH SCOVRONEK, Primary Examiner. MORRIS O. WOLK, Examiner. I. ZATARGA, Assistant Examiner.
Claims (1)
1. A METHOD OF REMOVING FERROUS SULFIDE FROM FERROUS METAL SURFACES COMPRISING PROVIDING AN AQUEOUS SOLUTION CONTAINING FROM ABOUT ONE TO ABOUT TEN PERCENT BY WEIGHT OF AN ACID SELECTED FROM THE GROUP CONSISTING OF HYDROCHLORIC AND SULFURIC ACIDS, FROM ABOUT 0.1 TO ABOUT 1.0 PERCENT BY WEIGHT OF COPPER ION, AND A THIOUREA COMPOUND SELECTED FROM THE GROUP CONSISTING OF THIOUREA, 1,3DIMETHYL THIOUREA, 1,3-DIETHYL THIOUREA, ALLYL THIOUREA, ETHYLENE THIOUREA, AND 1,3-DIISOPROPYL THIOUREA, SAID THIOUREA COMPOUND BEING PRESENT IN AN AMOUNT EQUIVALENT TO AN AMOUNT OF THIOUREA FROM ABOUT 2 TO ABOUT 20 TIMES THE WEIGHT OF COPPER ION PRESENT, AND CONTACTING THE FERROUS SULFIDE-CONTAINING FERROUS METAL SURFACE WITH SAID AQUEOUS SOLUTION, THEREBY TO REMOVE FERROUS SULFIDE.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US355113A US3353995A (en) | 1964-03-26 | 1964-03-26 | Removal of ferrous sulfide deposits |
| BE704792D BE704792A (en) | 1964-03-26 | 1967-10-06 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US355113A US3353995A (en) | 1964-03-26 | 1964-03-26 | Removal of ferrous sulfide deposits |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3353995A true US3353995A (en) | 1967-11-21 |
Family
ID=23396266
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US355113A Expired - Lifetime US3353995A (en) | 1964-03-26 | 1964-03-26 | Removal of ferrous sulfide deposits |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US3353995A (en) |
| BE (1) | BE704792A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3466192A (en) * | 1967-01-23 | 1969-09-09 | Amchem Prod | Corrosion prevention process |
| US4011097A (en) * | 1974-09-23 | 1977-03-08 | Sharp Thomas L | Method of removing iron sulfide and sludge from metal surfaces |
| US4276185A (en) * | 1980-02-04 | 1981-06-30 | Halliburton Company | Methods and compositions for removing deposits containing iron sulfide from surfaces comprising basic aqueous solutions of particular chelating agents |
| US4370197A (en) * | 1981-06-24 | 1983-01-25 | International Business Machines Corporation | Process for etching chrome |
| US4666625A (en) * | 1984-11-27 | 1987-05-19 | The Drackett Company | Method of cleaning clogged drains |
| US4778617A (en) * | 1984-11-27 | 1988-10-18 | The Drackett Company | Acid cleaner composition |
| US4993442A (en) * | 1981-11-05 | 1991-02-19 | Union Oil Company Of California | Methods for removing obstructions from conduits using sulfuric acid adducts |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2049517A (en) * | 1934-06-06 | 1936-08-04 | American Chem Paint Co | Method of and material for inhibiting or retarding acid corrosion of ferrous metals |
| US2388302A (en) * | 1943-03-12 | 1945-11-06 | American Optical Corp | Removal of iron from ceramic raw materials |
| US2662042A (en) * | 1950-02-01 | 1953-12-08 | Sun Oil Co | Progess for cleaning refining equipment |
| US2959555A (en) * | 1956-09-28 | 1960-11-08 | Dow Chemical Co | Copper and iron containing scale removal from ferrous metal |
-
1964
- 1964-03-26 US US355113A patent/US3353995A/en not_active Expired - Lifetime
-
1967
- 1967-10-06 BE BE704792D patent/BE704792A/xx unknown
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2049517A (en) * | 1934-06-06 | 1936-08-04 | American Chem Paint Co | Method of and material for inhibiting or retarding acid corrosion of ferrous metals |
| US2388302A (en) * | 1943-03-12 | 1945-11-06 | American Optical Corp | Removal of iron from ceramic raw materials |
| US2662042A (en) * | 1950-02-01 | 1953-12-08 | Sun Oil Co | Progess for cleaning refining equipment |
| US2959555A (en) * | 1956-09-28 | 1960-11-08 | Dow Chemical Co | Copper and iron containing scale removal from ferrous metal |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3466192A (en) * | 1967-01-23 | 1969-09-09 | Amchem Prod | Corrosion prevention process |
| US4011097A (en) * | 1974-09-23 | 1977-03-08 | Sharp Thomas L | Method of removing iron sulfide and sludge from metal surfaces |
| US4276185A (en) * | 1980-02-04 | 1981-06-30 | Halliburton Company | Methods and compositions for removing deposits containing iron sulfide from surfaces comprising basic aqueous solutions of particular chelating agents |
| US4370197A (en) * | 1981-06-24 | 1983-01-25 | International Business Machines Corporation | Process for etching chrome |
| US4993442A (en) * | 1981-11-05 | 1991-02-19 | Union Oil Company Of California | Methods for removing obstructions from conduits using sulfuric acid adducts |
| US4666625A (en) * | 1984-11-27 | 1987-05-19 | The Drackett Company | Method of cleaning clogged drains |
| US4778617A (en) * | 1984-11-27 | 1988-10-18 | The Drackett Company | Acid cleaner composition |
Also Published As
| Publication number | Publication date |
|---|---|
| BE704792A (en) | 1968-04-08 |
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