US2347916A - Container containing hydrogen sulphide vapor - Google Patents

Description

Patented May 2, 1944 await con'mnvm con'ramue nr noenm a summon varon Clifford P. Larrabee, Vandergrilt, Pa.

No Drawing. Application December 3, 1942,

' Serial No. 467,785

.5 Claims. (Cl. 206-84) I This invention relates to steel containers containing hydrogen sulphide vapor, the object being to provide an inexpensive steel container capable of resisting the peculiarccorfosion properties of this vapor. Such a steel container is exemplified by a steel storage tank containing sour petroleum cilwhich includes sulphur compounds and fills vapor consisting of hydrogen sulphide, moisture and air.

. other is present in a lower percentage, neither of I the tank'inside, unoccupied by the oil itself, with Since cost prohibits the use of'high-alloy steels, Y

exemplified by the stainless steels, which adequately-resist corrosion of this vapor, such steel containers are conventionally made of plain-carbon. or lowealloy structural steel. Heretofore, it has not been known how to make such steel adequately resistant to the corrosion of hydrogen sulphide vapor, the storage tank mentioned having an undesirably short service life due to corrosion of its parts contacted by the vapor.

The present invention is predicated on the discovery that, with but one exception, any the plain-carbon or low-alloy structural steels may have its resistance to corrosion by hydrogen sulphide vapor, greatly increased by" the addition of relatively small amounts of arsenic, which do not materially affect its cost. The exception is represented by those steels containing both chro- .mium and nickel with both these elements in excess of .25%. However, when either of these elements exceeds 25%, it can be rendered harmless, to the described eflect of the arsenic, by keeping the other of these elements below 25%. Because of cost, neither chromium nor.nickel should be included in excess of the percentages within low-alloy ranges, this, generally speaking, limiting these elements to maximums.

' Otherwise, the use of arsenic seems to functionproperly to increase the corrosion resistance to the vapor, in the case or any of the steels mentioned as conventionally used where cost'excludes the high-alloy types.

It follows that the invention consists of a steel container containing hydrogen sulphide vapor made of steel containing an amount of arsenic eflecting an increase in its resistance to corrosion.

by this vapor and with its balance iron excepting for elements harmless to this effect of the arsenic..

More specifically, the arsenic should preferably range in content from ".05 to 1.50%, and the maxirnum increase in resistance to corrosion by this vapor is effected by about a 1% arsenic content.

If the steel includes chromium and nickel, the contents of these elements that when one is present in excess of the must be adjusted so these named elements being present in suflicient amount, in any event, to provide the efiect of the arsenic to the same degree. In other words, there is no point in using the arsenic to effect a lowcost product of increased corrosion resistance. when the steel is of the high-alloy chromium or chromium-nickel type. Furthermore, there is no point in increasing either expensive element to a point where, by itself, the steels resistance to the vapor is increased beyond what could be afiorded by the arsenic.

Since the arsenic works with any 01 the structural steels, the invention may be defined as a container containing hydrogen sulphide vapor,

made of steel'containing from .05 to 1.05% carbon, from-.25 to 1.20% manganese, a maximum of .055% sulphur, a maximum of .20% phosphorus. from .50 to 1.50% arsenic, effecting an increase in its resistance to corrosion by the vapor, and the balance mainly iron. These compositional ranges cover the structurarsteels generally. In the case of the low-alloy structural steels, the balance is still considered as being mainly iron, this term being construedherein as covering ,the alloy amounts which are used in this type of steel.

- Therefore, the steel may contain from smaller amounts to not more than 5% of chromium or 5% of nickel, with the contents of these two justnamed elements adjusted, if used together, so that the content of one is less than..25% when the other exceeds this amount. Actually, these two elements are not normally used in such maximum amounts because of cost, but are usually restricted to a value less than 3%.

Heretofore, it has been known that arsenic,

along with copper, phosphorus, chromium, nickel, etc., enhancethe resistance of the lowalloy structural steels to corrosion 01' other types.

2 But it has not been known that of all these various alloys, arsenic exerts, a critically greater lncrease in the resistance 0! such steels to corrosion by hydrogen sulphide vapor, than do equal amounts or any of the others. The most practical embodiment of the arsenic, is to include it as the sole alloy in' what would otherwise be a plain-carbon structural steel, but other alloys may be required to 'meet special physical requiremenfs.

It is to be understood that the phosphorus content must be adjusted respecting the carbon content. Ingeneral, when the carbon content does not exceed about .10%, 1.20% phosphorus may be used, while with carbon contents exceeding about 30%. the phosphorus content should 7 not exceed about 345%.

I claim:

1. A container containing hydrogen sulphide vapor. made or steel containing 1mm .05 to 1.50% arsenic electing an' increase in its resistance to corrosionbythis vapor and with'its balancigen exceptins for or thearsenicui Y a 2. .A container containing hydrogemsulphide senic. eflectinganincrease in its resistance to corrosion by this vapor and with its balance iron exceptingior elements harmless to t eflect. or -thearsenic.""f 3. A container containing, hydrogen sulphide 1.50% arsenic effecting an increase in its resistance to corrosionby this'vapor and with its balgance iron excepting for elements harmless to this eflect of the, arsenic, including chromium and nickel with the contents of these elements adjusted so that whenone is present in excess of 25% the other is present in a lower percentelements, harmless to this t age, neither of these named elements being present'in sumcient amount. to provide the effect or the arsenic to; the same degree.

4.11 container containing va made of steel containing from .05 to 1.05%

irom'.25 to 1.20% manganese, a maxi-.

mum-.0: 105595, sulphur, a maximum of 42% phosphorus, from .50 to 1.50% arsenic eflectins an increase in its resistance to corrosion by the vapor, madeof steel-containing about1-%'ar-.,

vapon'and-the balance mainly iron.

15.! container containing hydrogen sulphide from .osto 1.05%

vapor, made of steel con I carbon, mm .25 to 1.20%,manganese, a maxi- -"vapor, made of-steel' containing from .05% .to J

mum ot- .055%-'sulp'hur, amaximum of .12% phosphorus, from so to 1.50% arsenic eflectim! an increase inits resistance .tocor'rosion by the vapor, and the balance mainly iron, including 7 iromsmaller amounts to not more than 5% oi chromium and 5%; nickel with the contents of these last two named elements adjusted so that the content or one is less than 25% when the other exceeds-this amount. I

CLIFFORD P. LARRABEE.

hydrogen sulphide