SG178245A1

SG178245A1 - Processes for removing hydrogen sulfide from refined hydrocarbo streams

Info

Publication number: SG178245A1
Application number: SG2012007647A
Authority: SG
Inventors: Malxolm Craig Winslow; Larry John Karas; Sherif Eldin
Original assignee: Gen Electric
Priority date: 2009-08-04
Filing date: 2010-07-02
Publication date: 2012-03-29
Also published as: US20110031165A1; WO2011016935A3; JP2013501126A; MX2012001530A; AU2010281621A1; EP2462207A2; KR20120055582A; CN102549114A; CA2770008A1; WO2011016935A2; RU2012103702A; BR112012002528A2

Abstract

A method for reducing the amount of hydrogen sulfide present in refined hydrocarbon streams and reducing the amount of corrosion in processing equipment contacting the refined hydrocarbon stream The method includes adding a corrosion inhibitor to the ielined In drocarbon stream in contact with the processing equipment to protect the processing equipment and adding glyo\al to the refined hydrυcaibυn stream in contact with the protected processing equipment The corrosion inhibitor includes an organic soluble compound having a nitrogen-containing ring

Description

PROCESSES FOR REMOVING HYDROGEN SULFIDE FROM REFINED

HYDROCARBON STREAMS

FIELD OF THE INVENTION

[G0G1] This invention relates generally to processing hydrocarbon media, and more particularly, to methods for removing hydrogen sulfide from a refined hydrocarbon stream.

BACKGROUND OF THE INVENTION

[0002] Hydrocarbon media, such as a refined hydrocarbon stream, may contain hydrogen sulfide, which is highly corrosive and poisonous in very small concentrations. The risk of exposure to hydrogen sulfide from handing hydrocarbon media is a health and safety concern during storage, transportation (shipping, truck or pipeline} and processing. [C003] Hydrogen sulfide scavengers can be used to remove hydrogen sulfide from hydrocarbon media. One type of hydrogen sulfide scavenger is glvoxal. During production of glvoxal, acidic byproducts are often formed. These byproducts can lead to increased corrosion rates dering hydrocarbon processing. When glyoxal 1s added to a refined hydrocarbon stream, the acidic byproducts, which are not soluble in the refined hydrocarbon stream, can settle out from the refined hydrocarbon stream into a separate aqueous phase. For example, the aqueous phase may run along the bottom of the processing or refinery equipment as small tributaries in pipelines or stagnate at the bottom of holding tanks. This acidic aqueous phase is highly corrosive and can cause troughing ins the processing or refinery equipment,

[0004] What is needed is an improved method for removing hydrogen sulfide from a refined hydrocarbon stream without causing corrosion to processing equipment.

BRIEF DESCRIPTION OF THE INVENTION

[CO0ST In one embodiment, a method for reducing the amount of hydrogen sulfide present in a refined hydrocarbon stream and reducing the amount of corrosion in processing equipment contacting the refined hydrocarbon stream, said method inclodes adding a corrosion inhibitor to the refined hydrocarbon stream in contact with the processing equipnient to protect the processing equipment and adding glvoxal to the refined hydrocarbon stream in contact with the protected processing equipment, wherein said corrosion inhibitor includes an organic soluble compound having a nitrogen- containing ring.

[0006] The various embodiments provide an improved hydrogen scavenging process for refined hydrocarbon streams that reduces hydrogen sulfide while minimizing corrosion to processing equipment,

DETAILED DESCRIPTION OF THE INVENTION

[0007] The singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. The endpoints of all ranges reciting the same characteristic are independently combinable and inclusive of the recited endpoint. All references are incorporated herein by reference. [C008] The modifier “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g, includes the tolerance ranges associated with measurement of the particular quantity).

[0009] “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, or that the subsequently identified material may or may not be present, and that the description includes instances where the event or circumstance occurs or where the material 1s present, and instances where the event or circumstance does not occur or the material 1s not present.

[0010] In one embodiment, a method for reducing the amount of hydrogen sulfide present in a refined hydrocarbon stream and reducing the amount of corrosion in processing equipment contacting the refined hydrocarbon stream, said method includes adding a corrosion inhibitor to the refined hydrocarbon stream in contact with the processing equipment to protect the processing equipment and adding glyoxal to the refined hydrocarbon stream in contact with the protected processing equipment, wherein said corrosion inhibitor includes an organic soluble compound having a nitrogen- containing ring.

[0011] The refined hydrocarbon stream may be any type of refined hydrocarbon stream containing hydrogen sulfide. In one embodiment, the refined hydrocarbon stream includes, but is not limited to, gas oil, naphtha, FCC slurry, diesel fuel, fuel oil, jet fuel, gasoline, Kerosene or vacuum residua. In one embodiment, the refined hydrocarbon stream may be at an elevated temperature. In another embodiment, the refined hydrocarbon stream may be at a temperature of from about ambient to about 150°C. In another embodiment, the refined hydrocarbon stream may be at a temperature of from about 40°C to about 100°C,

[0012] The processing equipment in contact with the refined hydrocarbon stream may be any type of equipment that can be used {for processing the refined hydrocarbon stream, such as pipelines and holding tanks. Processing equipment subject to corrosion is generally processing equipment made of carbon steel, but any type of processing equipment may be protected.

[0013] The corrosion inhibitor includes an organic soluble compound having a nitrogen- containing ring. In one embodiment, the corrosion inhibitor is miscible in the refined hydrocarbon streant.

[0014] In one embodiment, the nitrogen-containing ring may be a five-membered ring or a six-membered nang. In one embodiment, the nitrogen-containing ring may be an imidazoline derivative. In another embodiment, the corrosion inhibitor may be a fatty acid imidazoline. In one embodiment, the fatty acid imidazoline has the following structure:

N X

A . “

R' wherein R and R™ are each, separately, a Cg to Css alkyl, alkylene or aromatic group. In another embodiment, R and R” are each, separately, a Cg to Cop alkyl, alkylene or aromatic group. In another embodiment, R and R ave each, separately, a Cito Cy alkyl, alkylene or aromatic group. In another embodiment, R and R7 are each, separately, a Ce to Cys alkyl, alkylene or aromatic group having branched alkyl groups. In one embodiment, R may be stearyl, napthyl, palmyl, olyi, linolyl or inolenyl. In one erabodiment, R may be stearyl, napthyl, palmyl, olvl, linolyl or linolenvl.

[0015] In ove embodiment, the fatty acid imidazoline compound includes, bat is not limited to, stearic acid imidazoline, naphthenic acid imidazoline, palmitic acid imidazoline, oleic acid imidazoline, Hinoleic acid imidazoline or hnolenic acid imidazoline.

[0016] In ove embodiment, the fatty acid imidazoline may contain a mixture of two or more fatty acid imidazoline compounds.

[0017] In one embodiment, fatty acid imidazolines may be prepared by the condensation reaction of at least one fatty acid and diethylenctriamine. In one embodiment, the fatty acids may have a Cg to Cie chain length. In another embodiment, the fatty acids may have a Cy to Cys chain length. In another embodiment, the fatty acids may have a Cig to

Cis chain length. In one embodiment, the fatty acids may include natural acids derived from tall oils, oleic acid, stearic acid, palmitic acid, linoleic acid, linolenic acid or naphthenic acid or may include synthetically prepared fatty acids. The synthetically prepared fatty acids may include acids with an even number of carbon atoms or an odd number of carbon atoms. In one embodiment, the condensation reaction may be ata reaction temperature of up to about 400°F. In another embodiment, the reaction temperature may be from about 200°F to about 400°F.

[0018] In another embodiment, the nitrogen-contaimng ring may be a pyrimidine derivative. In another embodiment, the corrosion inhibitor may be a faity acid pyrunidine. In another embodiment, the fatty acid pyrimidine has the following structure:

N

PN

Re wherein R, and Ry, are each, separately, a Cs to Cag alkyl, alkylene or aromatic group. In another embodiment, R, and R, are each, separately, a Cs to Cy alkyl, alkylene or aromatic group. In another embodiment, R, and Ry, are each, separately, a Cie to Cig alkyl, alkylene or aromatic group. In one embodiment, R, and Ry, are each, separately, a

Cs to Cie alkyl, alkylene or aromatic group having branched alkyl groups. In one embodiment, R, may be stearyl, napthyl, palmyl, olyl, linolyt or linclenyl. In one embodiment, Ry may be stearyl, napthyl, palmyl, oly}, linolyl or linolenyl.

[0019] In one embodiment, the fatty acid pyrimidine compound includes, but is not limited to, stearic acid pyrimidine, naphthenic acid pyrimidine, palmitic actd pyrimidine, oleic acid pyrimidine, linoleic acid pyrimidine or linolenic acid pyrimidine.

[0020] In one embodiment, the fatty acid pynmidine may contain a mixture of two or maore fatty acid pyrimidine compounds.

[0021] In one embodiment, fatty acid pyrimidines may be prepared by the condensation reaction of at least one fatty acid with a fatty acid-dernived 1 3~propane diamine and paraformaldehyde. In one embodiment, the fatty acids may have a Cs to Css chain length.

In another embodiment, the fatty acids may have a Co to Cy cham length, In another embodiment, the faity acids may have a Cyq to Cig chain length. In one embodiment, the fatty acids may include natural acids derived from tall oils, oleic acid, stearic acid, palmitic acid, linoleic acid, Hnolenic acid or naphthenic acid or may include synthetically prepared fatty acids. The synthetically prepared fatty acids may include acids with an even number of carbon atoms or an odd number of carbon atoms. In one embodiment, the condensation reaction may be at a reaction temperature of up to about 400°F. In another embodiment, the reaction temperature may be from about 200°F to about 400°F,

[0022] The corrosion inhibitor may be added to the refined hydrocarbon stream in contact with the processing equipment to protect the processing equipment. In one t embodiment, the corrosion inhibitor 1s added to the refined hydrocarbon stream, which then contacts the processing equipment. In another embodiment, the corrosion inhibitor is added to the refined hydrocarbon stream while it is in contact with the processing equipment.

[0023] The corrosion inhibitor is added to the refined hydrocarbon stream in any conventional manner. In one embodiment, the corrosion inhibitor may be injected into the refined hydrocarbon stream. In one embodiment, the corrosion inhibitor may be injected into the refined hydrocarbon stream by a conventional in-line injection system and may be injected at any point in-line suitable to allow the corrosion inhibitor to mix with the refined hydrocarbon stream. The corrosion inhibitor may be added to the refined hydrocarbon stream in a continuous manner or can be added in one or more batch modes and repeated additions may be made.

[0024] In another embodiment, the corrosion inhibitor is injected into the refined hydrocarbon stream as the refined hydrocarbon stream is flowing through a pipeline. In one embodiment, the corrosion imhubitor is injected into the refined hydrocarbon stream as it enters a pipeline. In another embodiment, the corrosion inhibitor is injected into refined hydrocarbon stream in a holding tank. In another embodiment, the corrosion inhibitor is injected into the refined hydrocarbon stream as it enters a holding tank.

[0025] The corrosion inhibitor disperses into the refined hydrocarbon stream and eventually contacts the processing equipment and deposit onto the processing equipment, forming a protective coating or film. The corrosion inhibitor may be added in any amount suitable for forming a protective coating or film on the processing equipment. In one embodiment, the corrosion mhibitor may be added to the refined hydrocarbon stream in an amount of from about 2 ppm by volume to about 200 ppm by volume, based on the volume of the refined hydrocarbon stream. In another embodiment, the corrosion inhibitor may be added to the refined hydrocarbon streant in an amount of from about 5 ppm by volume to about 100 ppm by volume, based on the volume of the refined hydrocarbon stream. In another embodiment, the corrosion inhibitor is added to the refined hydrocarbon stream in an amount of from about 10 ppm by volume to about 100 ppm by volume, based on the volume of the refined hydrocarbon stream. In another embodiment, the corrosion inhibitor 13 added {o the refined hydrocarbon stream in an amount of from about 20 ppm by volume to about 100 ppm by volume, based on the volume of the refined hydrocarbon stream. The corrosion inhibitor may be added in a single batch or mav be added in continuing dosages to the refined hydrocarbon stream.

[0026] The corrosion iatlubitor will begin to deposit evenly on the processing equipment as it contacts the equipment. A protective coating will form on the processing equipment as the refined hydrocarbon stream containing the corrosion inhibitor continues to contact the processing equipment. The amount of time suitable for forming a protective coating will depend on many factors, such as the amount of corrosion whibitor 1 the refined hydrocarbon stream, the temperature of the refined hydrocarbon stream, the amount of time that the refined hydrocarbon stream is in contact with the processing equipment and the speed at which the refined hydrocarbon stream may be traveling as it contacts the processing equipment. In one embodiment, the corrosion inhibitor will provide a protective coating or film onto the processing equipment after at least about 5 minutes of adding the corrosion inhibitor to the refined hydrocarbon stream in contact with the processing equipment. In another embodiment, the corrosion inhibitor provides a protective coating onto the processing equipment from about § minutes to about 100 hours of adding the corrosion inhibitor to the refined hydrocarbon stream in contact with the processing equipment. In another embodiment, a protective filin or coating is formed onto the processing equipment from about 15 minutes to about 75 hours of adding the corrosion inhibitor to the refined hydrocarbon stream in contact with the processing equipment, In another embodiment, a protective film or coating 1s formed onto the processing equipment from about 30 minutes to about 60 hours of adding the corrosion inhibitor to the refined hydrocarbon stream in contact with the processing equapment. In another embodiment, a protective film or coating is formed onto the processing equipment from about 1 hour to about 50 hours of adding the corrosion inhibitor to the heavy oil 1 contact with the processing equipment. In another embodiment, a protective film or coating is formed onto the processing equipment from about 10 hours to about 40 hours of adding the corrosion inhibitor to the refined hydrocarbon stream in contact with the processing equipment. In another embodiment, the corrosion inhibitor provides a protective coating to the processing equipment from about 12 hours to about 36 hours of adding the corrosion inhibitor to the refined hydrocarbon stream in contact with the processing equipment. [00271 Glvoxal is added to the refined hydrocarbon stream in contact with the protected processing equipment to reduce the hydrogen sulfide. Glyoxal 1s a water-soluble aldehyde and may include oligomers of glvoxal. Glvoxal is commercially available as a 40 weight percent aqueous solution.

[0028] The glvoxal may be added to the refined hydrocarbon stream in any conventional manner. In one embodiment, the glvoxal may be injected into the refined hydrocarbon stream by a conventional in-line injection system and may be injected at any point in-line suitable to allow the glyoxal to mix with the refined hydrocarbon stream. The glvoxal may be added to the refined hydrocarbon stream in a continuous manner or can be added in one or more batch modes and repeated additions may be made.

[0029] The glyoxal is added to the refined hydrocarbon stream in any amount sufficient to reduce the levels of hvdrogen sulfide in the refined hydrocarbon stream. In one embodiment, glvoxal may be added in an amount of from about 1 ppm to about 3000 ppm by volume, based on the volume of the refined hydrocarbon stream. In another embodiment, glvoxal may be added 1 an amount of from about 10 ppm by volume to about 2000 ppm by volume, based on the volume of the refined hydrocarbon stream. In another embodiment, glvoxal may be added in an amount of from about 50 ppm by volume to about 1500 ppm by volume, based on the weight of the refined hydrocarbon stream. In another embodiment, glvoxal may be added in an amount of from about 100 ppm by volume to about 1200 ppm by volume, based on the volume of the refined hydrocarbon stream. [C030] Any amount of hydrogen sulfide in the refined hydrocarbon stream may be reduced and the actual amount of residual hydrogen sulfide will vary depending on the starting amount. In one embodiment, the hydrogen sulfide levels are reduced to 130 ppm by volume or less, as measured in the vapor phase, based on the volume of the refined hydrocarbon stream. In another embodiment, the hydrogen sulfide levels are reduced to 100 ppm by volume or less, as measured in the vapor phase, based on the volume of the refined hydrocarbon stream. In another embodiment, the hydrogen sulfide levels are reduced to 50 ppm by volume or less, as measured in the vapor phase, based on the volume of the refined hydrocarbon stream. In another embodiment, the hydrogen sulfide levels are reduced to 20 ppm by volume or less, as measured in the vapor phase, based on the volume of the refined hydrocarbon stream.

[0031] During the production of glyoxal, acidic byproducts are formed and the glyoxal can have a pH in the range of about 2 10 about 3. These byproducts can be highly corrosive. Glyoxal 1s water-based and after an initial dispersion throughout the refined hydrocarbon stream, will eventually settle out of the heavy oil in an aqueous phase. This aqueous phase will be very acidic and can corrode processing equipment. The coating or film formed by the corrosion inhibitor on the processing equipment protects the processing equipment and reduces or eliminates the corrosion from the acidic aqueous phase.

[0032] The corrosion iahubitor may continue to be added as the glyoxal 1s added to the refined hydrocarbon stream in contact with the protected processing equipment. The corrosion inhibitor will continue to deposit on the processing equipment and maintain the protection on the processing equipment. The additional corrosion inhibitor may be added in amounts of from about 1 ppm by volume to about 20 ppm by volume, based on the volume of the refined hydrocarbon stream. In another embodiment, the corrosion inhibitor may be added in an amount of from about § ppm by volume to about 10 ppm by volume, based on the volume of the refined hydrocarbon stream.

[0033] In one embodiment, a catalyst may be added to enhance the removal of the hydrogen sulfide. In one embodiment, the catalyst is a quaternary ammonium salt. The catalyst may be any suitable quaternary ammonium salt. In one embodiment, the catalyst has formula I: i]

RR RR4N TX i wherein Ry, Rg, Ry and Ry are each independently an alkyl group having from 1 to 30 carbon atoms, an aryl group having from 6 to 30 carbon atoms or an arylalkyl group having from 7 to 30 carbon atoms; and X is a halide, sulfate, nitrate or carboxylate. The alkyl groups and the aryl groups may be substituted or unsubstituted.

[0034] In one embodiment, Ry 1s an alkyl group having from 1 to 24 carbon atoms. In one embodiment, R; is an alkyl having from 1 to 24 carbon atoms, an aryl group having from 6 to 24 carbon atoms or an arylalkyl group having from 7 to 24 carbon atoms.

[0035] In one embodiment, Rs and Ry are each, independently, an alkyl group having from 1 to 24 carbon atoms. In another embodiment, Ry and Ry are each, independently, an alkyl group having from 1 to 4 carbon atoms.

[0036] The alkyl group includes, but 1s not linuted to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, decyl or dodecyl. The aryl group may be phenyl. The arvlalkyl group include may be benzyl. The halide may be chloride, bromide or iodide.

The sulfate may be a methyl sulfate. The nitrate may be a bisulfate nitrate, The carboxylate may be acetate.

[0037] In ove embodiment, the quaternary ammonium salt is alkyl benzyl ammonium chloride or benzyl cocoalkyl {C2-Cig) dimethylammonium chionide. In another embodiment, the quaternary ammonium salt includes, but is not limited to dicocoatkyl {C2-Cig) dimethylammonium chloride, ditallowdimethvlammoniom chloride, dithydrogenated tallow alkyl) dimethyl quaternary ammonium methyl chloride, methyl bis (2-hydroxyethyl cocoalkyl {Ci2-Cig) quaternary ammonium choride, dimethyi{(2- ethyl} tallow ammonium methyl sulfate, n-dodecyibenzyldimethylammonium chloride, n-

octadecyibenzyldimethyl ammonium chlonde, n~dodecyltrimethylammonium sulfate, sova alkyltrumethylammonitum chlonde or hydrogenated tallow alkyl (Z-ethylhyexyl) dimethyl quaternary ammonium methylsulfate.

[0038] In one embodiment, the catalyst is present from about 0.01 to about 15 percent by weight based on the weight of glvoxal. In another embodiment, the catalyst ts present from about 1 to about 10 percent by weight based on the weight of glvoxal.

[0039] The catalyst may be added to the refined hydrocarbon stream simultaneously with the glyoxal or may be added separately from the glyoxal. In one embodiment, the catalyst is preblended with the glyvoxal before being added to the refined hydrocarbon stream.

[0040] In order that those skilled in the art will be better able to practice the present disclosure, the following examples are given by way of illustration and not by way of limitation.

EXAMPLES

EXAMPLE 1

[0041] Glyoxal is an aqueous-based compound having a pH from about 2 to about 3.

When dispersed in refined hydrocarbon streams, it will eventually settle out of the refined hydrocarbon streams into an acidic aqueous phase and settle to the bottom of processing equipment causing corrosion. To test the efficacy of the corrosion inhibitor for reducing corrosion, the corrosion test was simulated mm water,

[0042] Two metal coupons of Carbon C1010 steel were weighed and added to two spindles mounted on a stirring shaft in an 800 ml Auto-Clave. The metal coupons were 180° from each other. The stirring shaft was placed into water and stirred at the revolutions per minute as shown in Table 1. The revolutions per minute were used to calculate the approximate flow through a pipeline and are shown in Table 1. A corrosion inhibitor was added to the water at room temperature in the amounts shown in Table 1. 1S minutes later, glvoxal was injected into the water in the amounts shown in Table 1.

The Aunto-Clave was sealed and the water was heated to about 180°F to simulate the temperature of a typical refined hydrocarbon stream during processing. After 4 hours, the metal coupons were tested for corrosion by measuring any weight loss of the metal coupons and averaging the metal coupons.

Table

Sample | Glyoxal'! | Corrosion {RPM | Pipeline | Weight | Corrosion {ppm by ¢ Inhibitor Flow Loss (g) | Rate (MPY) volume) (100 ppm by | (ftymin}

CE-1 None { None {450 4 0.0033 43.1 {CE-2 | 300 SK (5° 450 14 0.0083 11107 11500 SK1642 L430 4 0.0001 1 <05

Glyvoxal used contams 2% by weight quaternary ammonium catalyst and is available commercially as §-1730 from GE Water. 3 - . \ vg a . . ny TH, - “SK 15 is a water-soluble corrosion inhibitor available commercially as Philmplus 5K 13 from GE Water.

Np - . . . . yw . . - ~ TH, "SK 1642 is an organic-soluble corrosion inhibitor available commercially as Philmplus

SK 1642 from GE Walter and containing a 3:1 by weight blend of oleic acid pyrimidine and dimer/trimer acid.

[0043] The organic soluble corrosion inhibitor shows a marked decrease in corrosion compared with the blank {sample CE-1}. A water-soluble corrosion inhibitor was tested {sample CE-2}, but it actually increased the corrosion.

EXAMPLE 2

[0044] Additional corrosion tests were performed on organic soluble corrosion whibitors and were conducted in water in accordance with Example 1. Results are shown in Table 2,

Table 2

Sample | Glyoxal' | Corrosion Inhibitor | Corrosion | Corrosion Rate {ppm by | | Inhibitor LMPY) volume) | | {ppm by volume) : } 500 | Oleic acid Pymmidine and | 100 L392 { Dime Trimer Acid (3:1 wit eatin

CE4 1500 | DimerTemeracid’ 25 S18 2 500 | Oleic acid Imidazoling” | 25 L173 3 300 | Oleic acid Imidazoline and | 24 L233

Dimer/Trimer Acid (3:1 wt. Ratio) 4 500 \ Oleic acid Imidazoline and | 100 14.0

Hlydroxvacetic acid (3:1 wt ratio)’ 5300 [Olcicacid Pyrimidine” (100 1100 'Glyoxal used contains 2% by weight quaternary ammonium catalyst and is available commercially as §-1730 from GE Water. » . IN a - or fr ER ?Available commercially as Philmplus ~ SK 1642 from GE Walter. “Available commercially as Sylvadym™ T-18 from Sylvachem Corp. *Available commercially as CI-11C from GE Water. 2 * i | gs . = Yin § “Available commercially as SK28 from GE Water. “Available commercially as 3K7 from GE Water.

[0045] The organic soluble corrosion inhibitors in Samples 1-5 show improved corrosion resistance in comparison with the blank (sample CE-3) and in comparison with an organic soluble dimer/trimer acid {sample CE-4).

EXAMPLE 3

[0046] Corrosion experiments and hydrogen sulfide scavenging were tested in a mixture of oil gas and water in an 800 mi Auto-Clave. The gas oil was initially spiked with an approximate 0.5 wt. % solation of HS in kerosene before being mixed with the water.

Two metal coupons of Carbon C1010 steel were weighed and added to two spindles mounted on a stirring shaft. The metal coupons were 180° from each other. The stirnng shaft was placed into the gas oil and water mixture and stirred at 300 rpm. The mixture of oil gas and water was 200 mi of gas oil and 400 ml of water. The 2:1 volume ratio of water to gas oil ensured that the coupons were always immersed in water @ 300 rpm to test the corrosion in an aqueous phase. A corrosion inhibitor was added to the gas oil mixture at room temperature in the amounts shown in Table 3. 135 minutes later, glvoxal was injected into the gas oil mixture in the amounts shown in Table 3. The Aunto-Clave was sealed and the gas aif and water mixture was heated to about 180°F to simulate a typical processing temperature. After 4 hours, the metal coupons were tested for corrosion by measuring any weight loss of the metal coupons, averaging the metal coupons and calculating the mils per year (MPY).

[0047] Hydrogen sulfide testing was performed using the modified ASTM §705-95 test that measures vapor phase HeS two hours after treatment (140°F) with Drager tubes.

Final H2S concentration measurements are shown in Table 3.

Tahle 3

Sample | Glyvoxal' | Corrosion Inhibitor | Corrosion | Corrosion Final HoS {ppm by | \ Inhibitor | Rate (mpy) | (ppm) volume) | {ppm by volume) 1 500 | Oleic acid Pyridine | 100 6.67 <15 : {and Dimer/Trimer Acid {ra PPR ! !

TGlyoxal used contains 2% by weight quaternary ammonium catalyst and is available commercially as $-1750 from GE Waler. “Available commercially as Philmplus 5K 1642 from GE Water.

[0048] Both samples (CE-S and 1) show removal of hydrogen sulfide while Sample 1 also shows a marked decrease in corrosion compared with the blank (sample CE-3).

[0049] While typical emobodiments have been set forth for the purpose of iHtustration, the foregoing descriptions should not be deemed to be a limitation on the scope herein.

Accordingly. various modifications, adaptations and alternatives may occur to one skilled in the art without departing from the spirit and scope herein.

Claims

WHAT IS CLAIMED IS: Having described the Invention that which is claimed is: i A method for reducing the amount of hydrogen sulfide present in a refined hydrocarbon stream and reducing the amount of corrosion in processing equipment contacting the refined hydrocarbon stream, said method comprising adding a corrosion inhibitor to the refined hydrocarbon stream in contact with the processing equipment to protect the processing equipment and adding glyoxal to the refined hydrocarbon stream in contact with the protected processing equipment, wherein said corrosion mhibitor comprises an organic soluble compound having a nifrogen-containing ring.
2. The method of claim 1 wherein the refined hydrocarbon stream ts selected from the group consisting of gas oil, naphtha, FCU slurry, diesel fuel, fuel oil, jet fuel, gasoline, kerosene and vacuum residua.
3 The method of claum 1 wherein the refined hydrocarbon stream 1s at an elevated temperature.
4 The method of claim 3 wherein the refined hydrocarbon stream 1s at a temperature of from about ambient to about 150°C.
5. The method of claim 1 wherein the processing equipment is & pipeline or a holding tank.
6. The method of claim 3, wherein the processing equapment is made of carbon steel.
7. The method of claim 1, wherein the corrosion inhibitor comprises a five- membered or six-membered nitrogen-containing ring.
8. The method of claim 7, wherein corrosion inhibitor is an imidazoline derivative.
9. The method of claim &, wherein the corrosion inhibitor 1s a fatty acid imidazoline.
10. The method of claim 8, wherein the fatty acid imidazoline has the following structure: 1 R Rr wherein R and R are each, separately, a Cs to Use alkyl, alkylene or aromatic roup.
11. The method of claim 7, wherein the nifrogen-~containing ring is a pyvrmidine derivative.
12. The method of claim 11 wherein the pyrmidine derivative is a fatty acid pyrimidine.
13. The method of claim 12 wherein the fatty acid pyrimidine has the following structure: ] AN Rp wherein R, and Ry, are each, separately, a Cy to Cae alkyl, alkylene or aromatic group.
i4. The method of claim | wherein the corrosion inhibitor is injected into the refined hydrocarbon stream,
is. The method of claim t wherein the corrosion inhibitor ts present from about 2 ppm by volume to about 100 ppm by volume, based on the volume of the refined hydrocarbon stream.
16. The method of claim 1, wherein the corrosion inhibitor provides a protective coating onto the processing equipment after at least about 5 minutes of adding the corrosion inhibitor to the refined hydrocarbon stream in contact with the processing equipment.
17. The method of claim 1, wherein glvoxal is added to the refined hydrocarbon stream in an amount of from about 1 ppm to about 3000 ppm by volume, based on the volume of the refined hydrocarbon stream.
ig. The method of claim 1, wherein the corrosion inhibitor continues to be added to the refined hydrocarbon stream after the glvoxal has been added.
19. The method of claim 18, wherein the corrosion inhibitor continues to be added in an amount of from about 1 ppm by volume to about 20 ppm by volume, based on the volume of the refined hydrocarbon stream.
20. The method of clam 1, wherein the glyoxal turther comprises a catalyst.
21. The method of claim 20, wherein the catalyst is a quaternary ammonium salt.
22. The method of claim 21, wherein the catalyst has formula I: RiIRGRRIN TX I wherein Ry, Rz, Ry and Ry are each independently an alkyl group having from 1 to carbon atoms, an aryl group having from © to 30 carbon atoms or an arylalkyl group having from 7 to 30 carbon atoms; and X is a halide, sulfate, nitrate or carboxylate.
23. The method of claim 22, wherein the quaternary ammonium salt is alkyl benzyl ammonium chioride or benzyl cocoalkyl {(Cy2-Cig) dimethylammonium chloride.
24. The method of claim 21, wherein the catalyst ts present from about 0.01 to about percent by weight based on the weight of glyoxal.