US2013185A - Coating for vessels - Google Patents

Description

Patented Sept. '3, 193 Q V I i it i UNITED s A'r s PATENT OFFICE COATING FOR VESSELS Ross 0. Powell, Forest Hills, N. Y., assignor to The Texas Company, New York, N. Y., a corporation of Delaware No Drawing. Application June 24, 1932, Serial No. 619,127

2 Claims. (Cl. Ell-70.1)

This invention relates in general to corrosive spraying a corrosive resistant metal or metal alresistant vessels and more especially to a methloy therein while the vessel is at an elevated od of coating a vessel with a corrosive resistant temperature and being rolled. material. Still another object of my invention is to pro- 5 In many operations involving the use of vessels 'vide a vessel having a corrosive resisting coating 5 I subjected to high temperatures and in some inapplied thereto while the vessel is being rolled stances high pressures, and where a corrosive and at a high temperature. I substance is being treated, it is generally the With these and other objects in view,'whic'h practice to fabricate these vessels to a thickness may be incident to my improvement, the inven- 0 sufliciently great to provide for future corrosion tion consists in the several method steps to be without sacrificing safety. Iron or carbon steel, hereinafter set forth in detail for providing andue to its cheapness and strength is generally interior coating for a vessel, with the under- .employed. These metals are readily attacked by standing that the several steps may be varied corrosive substances and, for example, in the without departing from the spirit and scope of treatment of hydrocarbon oils the free sulphur the appended claims.

and/or sulphur compounds evolved during the My invention may be carried out with a vessel J treatment rapidly corrode the portions of the of any size or shape. While it will be described vesselwith which they contact. in connection with large vessels, it is equally It is of prime importance in the coating of a applicable to smaller'ones, such for instance, as p vessel with a corrosive resistant material to protubes forming a heating coil for use in the con- 20 vide a surface of a non-porous nature which'is version of hydrocarbon oils. impervious to corrosive substances. If the -coat- A large vessel may be made from a single billet ing is porous, which presents what is commonly of metal, such as carbon steel. The billet may known as pits in the coating surface, the co 0- be of the pierced billet type and forced to the desive substance being treated, whether in liquid sired size and shape by a plurality of rollers suitor vaporous form, enters these pits and attacks ably positioned with respect to the pierced billet. thebase metal. The deleterious effects of spotted A vessel may also be made up of a plurality of corrosion. arenot only hard to detect but also sections. The sections to be formed into the ves greatly impair the safe operation of the vessel. sel are rolled to the correct curvature and spot 7 In the treatment of hydrocarbonoils in a welded together at the joints. The joints are pressure still-or vessel, the vapors or liquid enter then grooved out and further welded by special 0 the pits and gradually corrode the base metal welding machines to form tight joints.

'to such an extent that future operation of the .In accordance" with my invention an interior same would be extremely .dangerous. It would coating of corrosive resistant material is applied be advantageous, therefore, to provide a coating to any type vessel to prevent corrosion of the on the inside shell of a metallic vesselfree from base metal. The corrosive resistant material pits and capable of resisting corrosion. may, for instance, be chromium or one of its. alloys.

In accordance with my invention there is pro- It is well known that chromium or its alloys posvided a method of applying a corrosive resistant sesses high corrosive resistant properties, espe- 40 metal or metal alloy coating to the interior of a cially to the corrosive substance present or .evolved 40 vessel which closely adheres to the base metal in the cracking of hydrocarbon oils. Another and presents an even smooth surface charactermetal possessing high corrosive resistant properized by the lack of porosity or tpits extending ties is aluminum and this metal can also be used through tothe base metal. f' as a coating as will hereinafter appear.

5 An object of my invention is to provide a. My invention will now be described in connecmethod of coating the interior of a vessel with a. tion with coating the interior of a yessel manucorrosive resistant coating of a homogeneous nafactured by either of the above mentioned methture and free frompits. ods with a'corroslve resistant material, although Another object of my invention is to provide a it is to be clearly understood that the invention method of coating the interior of a vessel by is applicable to a vessel manufactured by any 50 spraying a corrosive resistant metal or metal almethod, whether new or' previously used. loytherein while the vessel is at an elevated In manufacturing a vessel with a single billet temperature. g v of the pierced type, the billet is rotated while at A further object of my invention is to provide an elevated temperature and this rotation. with 56 a method of coating the interior of a vessel by the aid of suitable rollers forms a vessel of the 5 desired size and shape. When the vessel has reached the desired size and shape, it is still at an elevated temperature and is allowed to gradually cool. My invention has to do with the application of the corrosive resistant coating while the vessel is still at an elevated temperature and being rotated.

I propose to insert a Schoop gun or any other suitable type of pressure spraying device into the interior of the vessel. The spraying device is adapted to spray the corrosive resistant material in a molten state evenly onto the interior surface of the vessel with great force and while the vessel is still at an elevated temperature. Prior to the spraying of the interior of the vessel, it has been found desirable to remove the scale which has been formed thereon. This may be accomplished by inserting superheated steam under pressure into the vessel which functions to remove the scaling particles. While I have mentioned steam as being satisfactory for removing the scale, it is to be understood that other scale removing mediums, may be employed. It is also within the scope of my invention to use a flux, whether a scaling medium has been used, or not, to aid fusion between the coating material and the base metal.

After the scale has been removed and the vessel is still at an elevated temperature, the molten corrosive resistant material is forced through the spraying device at a plurality of outlets. material contacts the interior of the vessel with great force and due to the elevated temperature of both the vessel and the corrosive resistant material, fusion between the two takes place. The chromium coating not only forms a layer above the base metal but also penetrates same and alloys therewith to form in effect an integral surface coating. Another feature of my invention is the application of the coating material while the vessel is being rolled. I have found that the rolling operation aids in the fusion of the coating material'with the base metal and reduces the porosity thereof. Moreover, the rolling operation tends to even out the coating material and provides a smooth homogeneous coating of uniform thickness throughout.

In providing a chromium coating in accordance with my invention, the billet is heated to a temperature of .around 2400 F. and rolled at this temperature on suitable rollers to form a vessel of the desired size and shape. superheated steam or any other suitable scaling medium is then introduced into the rotating vessel to remove any scale formed on theinterior thereof. The temperature of the vessel is then reduced to between 1900-and 2300 F. and the chromium coatingin a molten form is evenly sprayed onto the interior of the vessel by the pressure spraying device. The chromium readily fuses with the base metal of the vessel between these temperatures and this fusion together with the rolling action causes the chromium to-penetrate the base metal and closely adhere thereto andform a smooth homogeneous coating free from .pits. The thickness of the coating will vary depending upon the quantity of chromium forced through the spraying device. I havefound that a coating as thin as 1/190 of an inch is satisfactory in viewof the excellent corrosive resistant propertiesof chromium. While I have specifically mentioned the application of chromium as a coating material, it is to be understood that chromium s1- loys, such as chromium and nickel and chromium-iron and nickel or any other chromium alloys maybe used. The thickness of the resisting coating has been merely given as an example and it is to be clearly understood that this thickness may also be varied without departing from the spirit of my invention.

Aluminum is also very satisfactory in resisting corrosion, especially in the treatment of hydrocarbon oils. If an aluminum coating .is used, the vessel is cooled to a temperature of.say, between 900 to 1150 F. and the rolling operation continued. The aluminum may be applied either in a molten or powdered form to the interior surface, after the scale has been removed, by any suitable pressure device such as a Schoop gun.

The aluminum readily fuses with the base metal between these temperatures and forms a protective coating free from pits and of a smooth homogeneous nature. As in the case of applying a chromium coating to the interior of the vessel, the rolling of the vessel and the application of the aluminum while the vessel is at an elevated temperature forms in effect an integral surface coating of a non-porous nature.

Aluminum foil may also be used in accordance with my invention. Aluminum foil is available in sheet form and a sheet or the necessary number of sheets of the foil may be inserted into the vessel to properly cover the interior or any desired portion thereof. The heat of the vessel, that is between 900 and 1150 F., is transmitted to the aluminum foil. This transmittal heat starts fusion between the aluminum foil and the base metal of the vessel and this fusion aided by the rolling operation provides an aluminum coating of a smooth homogeneous nature free from pits and capable of resisting corrosion. I propose to use aluminum foil made up in sheets of approximately 1.5/ 100 of an inch thickness. This specific thickness, however, is merely given as .an example as obviously my aluminum coating may be applied in varying degrees of thickness and with one or more layers, if desired.

When a vessel is made in sections and the sections suitably welded together, heat is applied to satisfactorily anneal the various joints. The vessel is generally placed in a suitable furnace forthe annealing operation.- It is during this operation that I propose to carry out my invention on .a vessel manufactured by this method. The vessel during the annealing operation may be raised to a temperature sufllciently high to correctly anneal same and also to present a sufliciently hot interior surface to the coating material to be applied. After the temperature of the vessel has been raised, a protective coating may be applied in the manner already described. The vessel may also be rolled by any suitable means as the protective coating is being applied.

My invention has been primarily described in connection with the manufacture of'new vessels. It is to be understood that it is likewise applicable to the coating of the interior of old vessels to prevent further corrosion thereof. In carrying out my invention with an old vessel, the interior thereof may be suitably sand blasted to remove all deposits therefrom. The vessel may then be heated by any suitable heating device and raised to an elevated temperature. Any scale resulting from the heating operation may be removed, and the protective coating applied as already described. -If the vessel is in place, corrosive resistant foil in a sheet or sheets may be inserted within the vessel. after same has been cleaned, and the heating and rolling action will cause the coating material to fuse with the base I metal to provide a uon-Lporom aoiaiss protective coating of a smooth homogeneous na My protective coating of corrosive resistant ma' terial may also be applied to vessels in place by any suitable sp aying device. The'vessel is first sand blasted to remove any deposits and raised to a high temperature in any suitable manner, such as'by suitably flrin'g same. The scale is removed and when the temperature of the vessel has reached the point where the base metal will readily fuse with the coating material, the coating material is sprayed onto the interior surface of the vesselin molten form withgreat force. By evenly spraying the corrosive resistant I the interior of the vessel with great force, the

protective layer tightly adheres to and penetrates the base metal to such an extent as to provide a non-porous and smooth homogeneous coating. s w

The heating operation described herein, whether it be in the manufacture 0! a new vessel or the application of a coating to an old vessel;

may be, carried out under ordinary atmospheric conditions or under sub-atmospheric conditions. he applied in the presence of an inert gas, such as nitrogen.

will be readily seen that Moreover, the coating may From the foregoing it I haveprovided a method whereby a non-porous homogeneous coating While I have specifically mentioned that. my

' invention is well adapted to prevent the corrosive being reated.

- it is to be understood that it is notlimited to vessels used in such] processes as obviouslyitis ap-- action of hydrocarbon oils while @Iclaiimi Y 1. A method of protectingthe interior surface of an oil refining vessel fromcorrosion which. materialonto 7 pressure to said coating of substantiallyuniform thickness.-

of corrosive resistant ma-.

. molten form against terial is evenly applied to the interior ofa vesseh said vessel.

ingeneral. I Q I wish it to be understood thatI do not confine myself to the precisedetails herein set forth in the preferred manner ofcarrying out ny'im vention as it is apparent that many changesiand variations may be made by those skilled in the art without departing fromuthe spiritvof the inv N vention, or exceeding the scope of the appended.

claims comprisesheating said vesselxto a'tempe'rature in the neighborhood of from 1900 to 2300" 1 apmy;

ingfl'a chromium lining to' said vessel in "finely divided form while said vessel is at'said elevated pll l mechanical a 1 temperature and thereafter lining to form a; dense, compact 2 A method of manufacturing an oil refining vessel having a protective neighborhood of 2400 F., thereafter rolling said 1 billet into a vessel of the desired and shape, thereafter removing scale formed asa result of said. rolling operation, spraying" chromium in the interior surface of the vessel so formed and while said vessel is at a tempera'ture ranging from 1900' to 23001 F., and

lining which comprises i heating a metal billet to a temperature inthe thereafter applying. mechanical pressure to said lining-to form a dense, compact coating within.

. "ROSS crowns;

plicable the treatment corrosive