US2568111A - Corrosion-resistant storage tank - Google Patents

Description

P 18, 1951 D. c. BOND 2,568,111

CORROSION RESISTANT STORAGE TANK Filed April 19, 1946 2 Sheets-Sheet 1 3 5 3 5 25 E -25 11 r: z 1/11 3 r 1 5 E 15 E E M 2 z 5 2-21 00009. one

INVENT OR.

Donald (QBoruZ {i m 4 A f;

ATTORNEY p 18, 1951 1 D. c. BOND 2,568,111

CORROSION RESISTANT STORAGE TANK Filed April 19, 1946 2 Sheets-Sheet 2 IN V EN TOR.

DONALD C. BOND BY a corrosion-resistant substance. sheeted fibrous material, such as heavy wrapping Patented Sept. 18, 1951 1 2,568,111 v conaosron-nnsrs'mm s'ronaoa TANK Donald c. none, Normal-mam, assignor to'lhe'; Pure Oil Company, Chicago, 111., a corporation I of Ohio Application April 19,1.946, Serial No. cease;

3 Clalms; (craze-63") f This invention relates to corrosion-resistant containers and to a method for rendering steel containers non-corrosive to mineral oils, brine and gases containing corrosive reagents, such as hydrogen sulfide.

Considerable difficulty is experienced in the storage of crude petroleum 011 due to the fact that such oils contain brine in admixture there with, and, contain dissolved or include therein gases containing a small amount of hydrogen sulfide. The brine and the hydrogen sulfide exert a corrosive action on the steel walls of the containers, eventually eating through the walls and causing leakage and necessitating replace-.

ment of the container or storage vessel.

Attempts have been made tocoat the inside walls of steel storage vessels with corrosion-resistant coatings, but in general, such coatings have not been satisfactory for the reason that they either peel or crack oif, thereby exposing the walls of the container to the corrosive action of the brine, hydrogen sulfide and other corrosive agents.

I have discovered that the inside walls of steel and other metal containers can be protected against corrosion by lining such containers with flexible sheeted fibrous material or woven fabric which has been impregnated and/or coated with Any su table paper, canvas, roofing felt, woven glassj flber's, nylon or other synthetic resin material may be used. As corrosion-resistant substances with which the fibrous or woven sheets are impreg nated and/or coated may be mentioned Amer- .coat 23, a vinyl resin,'Ucilon, a vinyl resin, or

various resins and thermoplastics, such as phenol-formaldehyde, phenol-paraformaldehyde and thiourea-furfural resins and coal tar pitch.

My invention is particularly applicable to the protection of storage tanks made up of a plurality of staves or sections bolted together. Howfibrous material or fabric adapted to be applied to the stave or section shown in Figure 1; Figure 3' is a perspective view of a bolted storage tank made up of staves or sections corresponding to thestaveshowninliigurol; andl igureliaan 1 z H enlarged perspective view partly .in section, of the tank shown in Figure 3.

Referring more particularly to the drawings,

the numeral l indicates generally a stave or section of a bolted cylindrical storage tank. Section I is a rectangular, arcuate shaped plate formed with the tabs or flanges 3 and 5 along the upper and lower edges thereof. The tabs or flanges 3 and 5 are bent outwardly atsubstantially right angles to the face of the stave; The lateral edges 1 and 9 of the stave are crimped or tapered in accordance with standard practice. The flanges and lateral edges have holes ll punched therein at spaced intervals in order to permit bolts i3 to pass therethrough and hold the staves together, as well as to fasten the top and bottom of the tank to the staves. As shown in Figure 3 the roof is also made of wedge-shaped sections with holes punched along the edges thereof. The tank is of conventional construction generally used in the oil producing industry.

A sheet of fibrous material or woven fabric I5 is cut and shaped to flt against the inner surface of the stave I. The sheet I5 is also formed with tabs l1, l9 and 2| along the edges thereof,-

whichtabs as well as the edge 23 are punched with holes 25. The tabs l1 and I! are adapted to be folded back over the tabs or flanges 3 and 5 of thestave I with the holes of the sheet tabs in alignment with the holes of the stave tabs or flanges. The tab 2| is adapted to be folded back over the lateral edge of the stave inside the tank and to be bolted between the overlapping edges of two adjacent staves. As will be seen from Figure 2 an-extra row of holes 21 is punched along the right edge of the sheet 15 in order to accommodate bolts when the sheet is bent around the edge of the stave. The rows of holes 25 and 21 along the right edge of the sheet are in alignment with each other. The sheets l5 may or may not be fastened to the stave i by suitable adhesive, although we prefer to adhere the sheets to the staves in order to cause the sheets to lie snug against the surface of the stave. Any suitable adhesive may be used to cause the sheet to adhere to the stave. In general, I prefer tov use as adhesive a material similar to that which-is used to impregnate and/or coat thesheet. The roof and bottom will be lined with protective sheets'in the same manner as the'side walls of the tank. Sheets will be'cut of the same size and shape as the roof and bottom section 29f except that an extra tab correspondingto tab II of sheet l5 will be provided along one edge to be bent overthe inside edgeof the stave and be 3 bolted between overlapping edges of adjacent staves. The sheet sections will be punched with holes, as described in connection with sheet l5, to align with the holes of the roof and bottom sections.

very rapidly to 300 F. over a period of 20 minutes. The material to be impregnated and/ or coated is dipped in the resin while it is liquid. The resin becomes hard and transparent after one hour and is insoluble in ordinary organic solvent.

Sheets of fibrous material or fabric may be 5 -Strips of wrapping paper and of canvas were impregnated with the corrosion resistant material impregnated with resins prepared as aforesaid by running the material through a bath of the and tested by immersing the strips in a bath concorrosion-resistant material either in heated talning brine and sour crude mineral oil, so that liquid form or dissolved in a suitable solvent, and the lower third of the strip was covered by brine, thereafter allowing the sheet to dry before cutthe middle third was covered by oil, and the ting it into proper sizes for application to the upper third was exposed to the crude oil vapors. staves or sections. Such operations are well The bath was covered and connected to a reflux known in the roofing industry where cheap felt condenser and placed in a water bath maintained in roll form is run through a molten bath of tar at the desired testing temperature. The results or asphalt in order to impregnate the felt, and of the tests are given in the following table.

Table Test in brine and crude oil Material g.Resi Type of Resin Impregnated Solvent ccerslol- Temp. of D8 8 gfi Test OF y Resin Phenol-Formaldehyde (N HlOH catalyst) Wrapping Papcr.. Alcohol, Toluene" 1.9 140 31 None Thiourea-furfural (HCl catalyst) dc None H0 31 None Styrene (Sne l catalyst) None 15 None Phenol-formaldehyde (NH4OH catalyst) Canvas-.. Alcohol, Toluene. 1.9 140 43 None Thiourea-iurrural (HCl catalyst) None 140 43 None thereafter run between hot rolls to which asphalt is applied in order to coat the sheet, after which the sheet is cut into desired shapes in a continuous operation.

Suitable resins for impregnating and/ or coating the fibrous material or fabric for use in lining storage tanks may be made in the following manner: 2 mols of phenol and 2.2 mols of a 35% aqueous formaldehyde solution are placed in a three necked flask equipped with a mechanical stirrer, thermometer, and reflux condenser. The reaction mixture is heated to 176 F. and 15 grams of concentrated ammonium hydroxide solution added. The mixture is raised to 248 F. and the reaction allowed to continue under reflux for minutes. The resulting resin is cooled by immersing the flask in a bath of cold water and then immediately dehydrated by distilling off the water under reduced pressure. When the temperature of the resin undergoing distillation reaches 176 F. the flask is removed from the oil bath which is used to heat the flask during the dehydrating operation, and 1.2 grams of stearic acid is added with stirring. The resulting phenolformaldehyde resin is dissolved in 125 cc. of a mixture containing 9 volumes of ethyl alcohol and one volume of toluene.

The phenol-paraformaldehyde resin may be made in the same manner as the phenol-formaldehyde resin except that the dehydrating step is omitted.

A thiourea-furfural resin may be made by mixing 100 parts by weight of water with 100 parts by weight of thiourea and 197 parts by Weight of furfural. The mixture is heated to 95 F. and stirred until the thiourea is dissolved. The mixture is cooled to 80 F. and 32 cc. of concentrated hydrochloric acid is added slowly with stirring. The temperature is not allowed to exceed 110 F. When the viscosity of the resin reaches that of glycerine the fabric or fibrous sheets are dipped into the resin in order to impregnate and/or coat them, and allowed to drain. The resin becomes hard after one hour.

I Styrene resin may be prepared by mixing 66 cc. of styrene with 16 drops of stannic chloride and raising the temperature slowly at first, and then From the table it is apparent that the coated strips were unaffected by the crude oil, brine or vapors liberated from the crude.

As previously said, I prefer to fasten the corrosion-resistant sheets to the inner Walls of the tank, and this may be done by coating the walls of the tank with an adhesive to which the sheets are applied, or by applying heat and pressure to the sheets as they are applied to the staves, causing the plastic, resin or other coating material to adhere to the metal.

Instead of impregnating and/or coating the corrosion-resistant sheets prior to applying them to the inner walls of the tank the uncoated sheets of fibrous material or fabric may be applied to the tank and painted or coated with the corrosion-resistant paint or plastic material after the tank has been completely assembled.

The joints between the sections of lining material may be sealed with thermoplastic or resinous material of the same nature as that used to coat the sheets.

When using impregnated and/or coated felt to line the inner walls of the tank it will be unnecessary to provide gaskets between the flanges, since the sheet sections will serve as gaskets to prevent leakage. However, gaskets may be used if desired.

Instead of using impregnated and/or coated sheets of fibrous material or fabric as a protective lining for the tank, sheets made of flexible or elastic synthetic rubber such as Thiokol which are resistant to attack by the corrosive agents encountered and to the materials to be stored may be used.

By applying sheets to the. staves and/or sections of the tank in the manner shown in the drawings and described herein, every portion of the tank will be protected against corrosion. Furthermore, if any portion of the linin becomes damaged it can be readily removed and replaced.

It will-be seen, therefore, that I have provided an economical means for protecting steel and other metal storage tanks against corrosion.

It is claimed:

1. A liquid storage tank comprising, a plurality rosion resistant flexible sheet material, each of said sections being adhered to and covering a corresponding section of said tank and the ends of said material being fastened between the flanges of said tank sections.

2. A storage tank in accordance with claim 1 in which said sheets are plastic impregnated and adhered to the inner wall of said tank sections.

3. A tank for holding corrosive hydrocarbon liquids and accompanying vapors, brine and fibrous material, resistant to deterioration by said hydrocarbons and accompanying materials. conformed to the shape oi said iron sections and being closely adhered to said iron sections with a. thermoplastic material. whereby the fibrous sections form a substantially continuous protective inner lining protecting the iron sections of said tank against corrosion by the hydrocarbons and accompanying material contained therein.

- DONALD C. BOND.

REFERENCES CITED The following references are of record in the flie of this patent:

UNITED STATES PATENTS .Number Name 7 Date 675,357 Maeonochie May 28, 1901 1,076,382 Maioney Oct. 21, 1913 1,489,725, Wilson Apr. 8. 1924 1,709,648 Aalborg --Apr. 16,1929 2,102,590 Gray et al. Dec. 21, 1937' 2,278,345 Benson Mar. 31, 1942 2,381,739 Gray Aug. "I, 196

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