US2516877A - Desulfurization of heavy petroleum hydrocarbons - Google Patents

Description

Aug. 1, 1950 w. A. HoRNE ETAL 2,516,877

DEsuLFURIzATIoN oF HEAVY PETROLEUM HYDRocARBoNs Filed sept. 27, 194s Patented Aug. l, 19.50

DESULFURIZATION OF HEAVY PETROLEUM HYDROCARBONS William A. Horne, Oakmont, and .James F. Jung, Pittsburgh, Pa., assignors -tocGulf Research & Development Company, Pittsburgh, Pa., a `corporation of Delaware Application September 27, 1946, ISerial No. 699;672

l31Cflaims. 1 This invention relates to the `desuliurizati'o of heavy petroleum hydrocarbons and more particularly to a method of :contacting heavy vpetroleum .hydrocarbons with a reacta'nt to remove the sulfur therefrom.

. `The eincient `.processing of high sulfur crudas, such as those from the `PermianrBasin of West Texas, has long beena problem of utmost `fimpcrtance to the renner of these sour crudos. The

sulfur has been `found highly lobjectionable.in l.

petroleum `oils for two primary reasons; namely, the problem it presents lto the refinery in handling the crude and heavy intermediates, andthe undesirable properties of the raw :products of refining.

The first of these problems is due to the corrosive :action of hydrogen sulde `vvliichis formed in numerous vreiining stages `from the decomposition of the sulfur compounds. Ordinary steels are rapidly corrodedtby hydrogen sulfide, espel.

cially at higher temperatures, so that it has been found necessary to use alloy steels at points of excessive attack, such as heat exchangers, or Ato use ordinary steel with frequentishut-downstfor replacements. VA specialized `technique `has been developed to combat this corrosion `by `the 1injection of neutralizers into the :stream just prior to the point of attack, but this system has no't proved entirely satisfactory.

While acid treating or bauxite desulfurization can be used `for straight-run gasolines and naphthas, no efficient method of Vdesulfurizing total crude and topped or reduced `'crude -has previously been developed. A desirableprocess will substantially reduce the 'corrosion difculties in the subsequent refining stages, and `at lthe same time solve `the problem of ltreating the raw products.

An object of the present invention 'is `to remove sulfur from heavy petroleum hydrocarbons.

A further object of the present invention is to remove sulfur in any form including hydrogen sulfide from heavy petroleum hydrocarbons.

These and other objects are achieved by the process of the present invention in .which a heavy petroleum hydrocarbon such as total crude, topped, or reduced .crude `is passed `together with hydrogen over a contact agent comprising a support and a `nickeliferous reactant initially predcminantly inthe form ofnickel oxide ata temperature in the range 750 to 950 terminating the treatment before a substantial `amount of `hydrogen suldeappears in the treated vapors and beforethe available nickel `content Aof the 2 contact :has `beenentirely converted into nickel sulfide, regenerating the contact iso thatit is predominantly in the form of nickel oxide and :lief using the regenerated contact in the process `flheprocess `generally` `comprisesmixing the change with yi-iydrogen and passing the `mixtllllc overa contact agent Vcol'itai-ning a reactantcm* sistinginitally of `nickel oxide. The nickel compound isrsunpcrted hon a carrervsuch as :alumina and by cont-act or Contact agent .as used here` in `is Ameant the `nickel @compound reactant and a carrier. During the reaction thenichel oxide is converted `.to `nickel sulfide and the `reactionis discontinued when `so much `nickel :sulde :is pres-I ent that theend product contains substantial hydrogen sulfide. Hydrogen `iisipresent inthe .range 300vto 4000 cubic `feet per Abarrel of oil charged. The reaction takes place at varying `temperatures and pressures depending uponthe charge stock, but `generally at a temperature in the range 750i to i950c F. and ata pressure inthe frange l100,110 1000 p. s. img. rIhe space `velocity ispreferably within the range `0.2 to `6:0 volumes of liquid charge per hour per volume 4of contact agent.` It is undesirable to havehydrogen sulde in the product and `*for this reason when about `5,0 :to .percent of the original nickel oxide becomes nickel sulfide, the contact :agent `should be regenerated. The regeneration `is 'accomplished by burning the contact ,agent with oxygen l contain-v ine :gasto reconvert the .reactant to .nicke1 oxide and `.to burn eti the carbonaceousvdeposit.

Our process fbegins with nickeloxide and dur-f` ing the `course of reaction .this is `couver-ted to nic-kel sulfide thereby removing; the: sulfur from the charge stock and liberating the `oxygen of the nickel; oxide asvvater. `There may also be ssimul` taneous reductionofsome of the nickel oxideto lower nickel oxides, `:such `as NizO, `vor metallic nickel with concurrent formation of Water. Subk sequently, part of these lower 'oxides `and/or metallicxnickel probably` react with the sulfur compounds .in the 'charge stock. i It .is possible that lduringthe reaction `.the ,nickel oxide, nickel sulde, or nickel metal may act ras catalystsbut the` 4net resultis :that of `the reaction :between nickel oxide and the sulfur, .Apparentlythe use of nickelcxide as the Astarting material inhibits thercrackfing activity of the` subsequently pro? duced metallic nickelto `.such an extent that cracking to gasand coke is ,not excessive. Elura` ther-more, since the .total .time Aspent by anypf the `reactant Vin the :metallic `.state ,is limited,- rapid loss vof 'activity through `sintering` is avoided,- The Amaximum processing ,period .is limited -to the,

3- interval during which no substantial amount of hydrogen sulde is liberated from the reactor.

The presence of hydrogen sulfide in the effluent product indicates that essentially all of the readily available nickel oxide and nickel has been converted to nickel sulfide. It is then necessary to regenerate the reactant with an oxygen containing gas which converts the nickel sulde back to nickel oxide, and simultaneously removes the sulfur as sulfur dioxide in recoverable concentrations. In general 50-60 'per cent of the total nickel oxide may be reacted before regeneration is necessary. This percentage is not invariant but depends on the operating conditions, sulfur content of the charge stock and contact. It has also been found that a minor amount of sulfur remains in the contact mass after regeneration as nickel sulfate. However, this nickel sulfate does not accumulate during subsequent cycles under our preferred conditions and apparently is not disadvantageous. The herein proposed theory of the action of the reactant should not be interpreted to limit the claims in any manner.

A flow sheet of the equipment for carrying out our desulfurization process is shown in the attached drawing in which the charge stock enters line and is pumped by means of pump 2 through line 3, product heat exchanger 4 and line 5 into heater 6 where it is heated to reaction temperature either before or after mixing with the hydrogen or hydrogen-rich gas from line 29. The mixture of charge and hydrogen or hydrogenrich gas at the desired reaction temperature passes through line 1, valve 8 and line 9 into the reaction chamber I containing the preferred contact. The desulfurized product leaves the reaction chamber by means of line valve |2, line I3, heat exchanger 4 and line I4 into the high pressure separator l5. The liquid product from the high pressure separator passes through line IB, cooler Il, line I3 and valve I9 into a low pressure separator 20. The desulfurized liquid product from the low pressure separator is withdrawn by means of valve 2| and line 22. Gases from the low pressure separator are released through valve 23 and line 24. The separated gases contain hydrogenv which may be recovered for recycle if desired in any conventional manner such as an `oil absorption and stripping system. The hydrogen-rich gas from the high pressure separator may also require some hydrogen enrichment which can also be carried out in a conventional manner. These gases normally pass through line 25, are compressed by pump 26, pass through line 27 and admix with fresh or makeup hydrogen from line 28 and valve 36. This hydrogen-rich gas is preheated either separately or in admixture with the charge stock in heater 6. This mixture then passes through line l as described previously.`

During this on-stream period valves 30, 3| and 32 remained closed. At the completion of the onstream period which varies depending on the charge stock and the conditions of reaction, pumps 2 and 26 are turned off and valves 8, I2 and 36 are closed. The pressure is released on contact bed l0 by means of valve 3| and the reactor is vacuum purged in conventional manner. Alternatively valve 3| and valve 32`may both be opened and the contact purged with an inert gas or steam. The purpose of the purge is to recover valuable hydrocarbons which remain in the contact bed. Following the purge, valve 3| is closed and valves 30 and 32 areo'pened andan oxygen- 4 containing gas is admitted to the reactor by means of line 34, valve 30 and line 9. The admission of this oxygen-containing gas in controlled amounts regenerates the contact converting the reactant to nickel oxide and simultaneously forms sulfur dioxide Which is vented from the reaction chamber by means of line Il, valve 32 and line 35 together with combustion gases from the carbonaceous deposit. This regeneration off-gas contains recoverable quantities of sulfur dioxide in amounts depending upon the quantity of sulfur originally present as nickel sulfide as well as the oxygen content of the regeneration gas. This sulfur dioxide may be recovered in any normal manner such as by solvent absorption and stripping. The sulfur dioxide-free regeneration off-gas may then serve to dilute the fresh regeneration gas admitted to the reaction chamber. Alternatively the sulfur dioxide-containing regeneration off-gas may serve to dilute the fresh regeneration gas. After regeneration is complete, inert gas orrsteam may again be used to iiush the system by closing valve 30 and opening valve 3| or the reaction chamber may be vacuum purged. The unit is then put on-stream again by closing valves 3| and 32, opening valves 8, I2 and 36 and starting pumps 2 and 26.

The foregoing description of the apparatus employed has been used as an example only. Multiple or single beds of fixed contact or iluidized contact as well as systems in which the contact is continuously charged and removed from the reaction zone followed by external regeneration are not excluded.

The following examples using the above described apparatus illustrate the reduction in sulfur and other advantages of the process when using several alternative contacts and charginga West Texas oil.

Eample 1 The contact agent employed'was an unreduced nickel oxide distributed over kieselguhr. This Was prepared by a controlled precipitation of basic nickel carbonate from nickel sulfate in the presence of kieselguhr, followed by controlled Washing and drying. The treated mixture of carbonate and kieselguhr was compressed into one-eighth inch diameter pellets, which were then decomposed by heating in an inert gas stream at 750 F. and the temperature maintained for approximately 1G hours. The contact in this form consisted of approximatelyv 75 per cent nickel oxide and 25 per cent kieselguhr.

West Texas Total Crude containing 1.46 per cent sulfur was processed at a temperature of 750 F., a pressure of -250 p. s. i. g., a space velocity of l volume of charge per hour per volume of contact and a hydrogen-to-oil ratio of 2000 cubic feet per barrel of liquid charge. The product contained 0.28 per cent sulfur. The gravity of the crude increased from 34.2 to 58.2 API. The total liquid recovery was about 99 volume per cent.

Example 2 The contact agent prepared in Example 1 was used in this example as Well as a charge of West Texas Total Crude containing 1.46 per cent sulfur.` The temperature used was 850 F., the pressure was 500 p. s. i. g., a liquid space velocity of 1 volume of charge per hour per volume of contact agent lwas used, and a hydrogen-to-oil ratio of 2000 cubic feet per barrel of `liquid charge was usedr- The product contained 0.18'per cent sulfur. The gravityv of the crude increased from At temperatures below 750 F; the desulfurizing activity of the contact diminisheswhereas above 950 F. excessive cracking reactions :resultin deg.g creased product recovery and rapid coke formation which deactivates the contact..v|f I;

At pressures below- 100 p. s. i. g; the partial pres sure of hydrogen is not sufficient `to maintain desulfurizing activity ,norv to suppress-cracking reactions which result in `coke formation. `Increasing the pressure/aboverlvOOO p. s. i. g. results in onlya slight incremental gainin desulfurization and is thus not commercially desirable.` t w Space velocities below 0.2 vol. of l`charge per hour per volume of contact agent result inexf cessive cracking reactions caused by the long con-v tact time, and at space velocities aboye,6.0 the contact time is too short to allow sufficient desulfurization. Hydrogen concentrations below 300 cu. ft. per barrel of charge stock are not surncient to maintain desulfurization activity nor to suppress undesirable cracking. Hydrogen concentrations above 4000 cu. ft. per barrel result in only a slight incremental gain in desulfurization. Higher space velocities and hydrogen concentrations than 6.0 vol. charge per hour per volume contact and 4000 cu, ft. per barrel, respectively, result in insuicient contact timeand the evolun tion of hydrogen sulde from the reactor within a relatively short processing period.V The vollimes of charge stock passed ovenone Volume of contact during the processing period depends on the per cent sulfur in the charge stock and the per cent nickel oxide in the contact but normally is in the range `of 1 to l0 volumes of charge per volume of contact. This throughput is limited f by the period during which no substantial hydrogen sulfide is evolved from the contact bed. They optimum regeneration conditions are ape proximately: ,Y i

Temperature, F li- 100G-1300 Pressure, p. s. i. g n; --500A Diluent gas to air ratio, vol./vol.' 04-7250 The regeneration temperature is limited to' that which does not produce a loss of mechanical perature and obtain the optimum regeneration time. Diluentgases may includesteam, fluegas, regeneration off-gas. etc.

The present process provides an eicient and economical process of reducing the sulfur 'content of heavy petroleum oils. Among thepa'rticular advantages is the increased yield of lowrsulfur` content gasoline, naphtha and'furnaceoil and a reduced yield of tar. In addition the gasoline 'obtained from the crude treated as herein described has higher clear and leaded octane numbers and higher lead susceptibility than the gasoline from the untreated charge. Further it reduces the equipment requirements for crude fractionation and cracking f and the maintenance thereof. There is no substantial hydrogen sulfide evolved thereby reducing maintenance 'andv equipment costs due to corrosion. i All vof these advantages accrue byl the use of our process due to the fact that theA sulfur com- Pounds inthe Ycrude are removed. and .hrdrosep eliminating the corrosion difficulties as well asthe undesirable properties of the products which are caused by the sulfur compounds. The increased yield of the lower boiling fractions and the reduced yield of the residuum or bottoms are im. portant advantages of this process. The reduction of the sulfur content of the crud substantially eliminates the corrosive action of hydrogen sulfide evolved during conventional processing and makes possible efficient processing of sour'crudes by refineries that are at prese ent only able to process low sulfur or sweet crudes.

The process is not to be confused with hydrogenation processes using metallic nickel as a cat. alyst.y We have found that if a nickeloxide is reduced with hydrogen prior to charging the petroleum oil, the eiiiciency of desulfurization is markedly reduced due to the high cracking activity of reduced nickel which results in excessive4 gas yields and rapid formation of a coke deposit on the contact.

In the following claims when we speak of absorbing sulfur from the hydrocarbon vapors it is tok be understood to mean that the sulfur con-- tained` in the vapors, in whatever form that it is present therein, is taken up by the reactant due to the formation of nickel sulfide.

What We claim is:

l. The process for desulfurizing a high boilin petroleiimv oil which comprises treating vapors thereof with a contact comprising a support and a nickeliferous reactant initially predominantly in the form of nickel oxide at a temperature in the range of 750 to 950 F. at a pressure above about pounds per square inch gauge and in the presence of hydrogen, absorbing sulfur fromthe vapors to form nickel sulfide on the contact', terminating the treatment before a substantial amount of hydrogen sulfide appears in the treated vapors and before about 60 per cent of the nickel content of the contact has been converted into nickel sulfide, regenerating the contact so that it is predominantly in the form of nickel 0X-, ide and re-using the regenerated contact in the process. L

2. The process for desulfurizing a high boilin petroleum oil which comprises treating Avapors thereof with a contact comprising a support and a nickeliferous reactant initially predominantlyin the form of nickel oxide at a temperature in the range of 750 to 950 F. at a pressure between about l100 and 1000 pounds per square inchl gauge and in the presence of hydrogen, absorbing sulfur from the vapors to form nickel sulfide, terminating the treatment before a substantial amount of hydrogen sulfide appears in the treated vapors and before about 60 per cent of' the nickel content of the contact has been con# verted into nickel sulfide, regenerating the con-i' tact so that it is predominantly in the form of` nickel oxide and re-using the regenerated contact in the process. j

` 3. The process for desulfurizing a high boiling petroleum oil which comprises treating vapors thereof with a contact comprising a support and' a nickeliferous reactant initially predominantly in the form of nickel oxide at a temperature'in the range of 750 to 950 F., at a pressure above. about 100 pounds per square inch gaugeL'at a space velocity in the range 0.2 to 6.0 liquid volumesof oil per hour per volume of contact and in the presence of hydrogen, absorbing sul,

fue. from` .the Vesprsto rormky nickel suifiqe, figg-L minating the; treatment before. a' substantial amount of hydrogen `sulfide appears in the treated vapors and before about `60' per cent of the nickel content of the contact has been converted into nickel sulfide, regenerating the contactA so` that it is predominantly in the form of nickel oxideand re`using the regenerated contact in the process.

4. In the process for desulfurizing a high boiling. petroleum :,oil which comprises. treating vaporsthereof with a contact comprising. a support and a` nickeliferous reactant initially predominantly in the form of nickel oxide at a temperature in the range of 750 to 950 F., at a pressure between about 100 and. 1000 pounds per square inch guage, at` a` spacel velocity in the range 0.2 to 6.0 liquid volumes of oil per hour per volume of contact and in the presence of hydrogen, absorbing sulfur from the vaporsto form nickel` sulnde, terminating the` treatment before a, substantial amount` of hydrogen sulfide. appears in. the. treated vapors and before about`60 per cent` of the nickel. contentY of the contact has beeni converted into` nickel sulfide, regenerating thef'contactfso. that. it is` predominantlyin the form of nickel-oxide and re-using the regenerated contact in the process. f

, 55.` `The process for desulfurizing a high boiling petroleum Voil* which comprises treating vapors thereof with contact comprising a support and a nickeliferous reactant initially predominantly in the form of nickel oxide at a temperature in the range of 750 to 950 F. at a pressure between about 100 and 1000 pounds per square inch gauge, at a space velocity in the range 0.2 to 6 0 liquid volumes of oil per hour per volume of contact and in the presence of hydrogen, said hydrogen being present in a concentration between about 300 and 4000 cubic feet per barrel of oil, absorbing sulfur from the vapors to form nickel sulfide, terminating the treatment before a substantial amount of hydrogen sulfide appears in the treated vapors and before about 60 per cent of the nickel content of the contact has been converted into nickel sulfide, regenerating the contact so that it is predominantly in the form of nickel oxide and re-using the regenerated contact in the process.

6. The process for desulfurizing total crude petroleum oil which comprises treating vapors thereof with a contact comprising a support and a nickeliferous reactant initially predominantly in the form of nickel oxide at a temperature in the range of 750 to 950 F. at a pressure above about 100 pounds per square inch gauge and in,

the presence of hydrogen, absorbing sulfur from the vapor to form nickel sulfide, terminating the treatment before a substantial amount of hydrogen sulfide appears in the treated vapors and before about 60 per cent of the nickel content of the contact has been converted into nickel sulfide, regenerating the contact so that it is premodinantly in the form of nickel oxide and re-using the regenerated contact in the process,

'7. The process for desulfurizirig topped crude petroleum oil which comprises treating vapors thereof with a contact comprising a support and a nickeliferous reactant initially predominantly in the form of nickel oxide at a temperature in the range of 750 to 950 F. at a pressure above about 100 pounds per square inch gauge and in the presence of hydrogen, absorbing sulfur from the vapors to form nickel sulfide, terminating the treatment before a substantial amount of hydrogen sulfide appears in the treated vapors and re-using the regenerated contact in the DIOCESS.

8. The processfor desulfurizing reduced crude petroleum oil which comprises treating vapors thereof with a contact comprising a support and a i nickelferous reactant initially predominantly in. the form, of nickel oxide at a temperature` in the range of 750 to 950 F, at a pressure above about.

pounds-perfsquare inch gauge and in the presence of hydrogen7 absorbing sulfur from the va.- pors to form nickel sulfide, `terminating the treatment before a substantial amount of hydrogen sulfide appears in the` treated` vapors and before aboutCGO per cent of the nickel content, of the contact has been converted into` nickel sulfide, re generating the contactrsc1 thatl it isy predominantly inthe form `of nickel oxide and rei-using theregenerated contact in the. process.

9. The process for desul'furizing a high` boiling petroleum oil which comprises treating` vapors. thereof, in the presence` of a diluent, with a contact comprising a support and a nickeliferous reactant. initially-predon'iinantly in the form of nickel` oxide at atemperature1 in therange of pourids per square inch'V gauge and` ing the pres-` ence of hydrogen, absorbing sulfur from the Vapors to form nickel sulfide, terminating the treatment before a substantial amount of hydrogen sulfide appears, in the treated vapors and before about 60 per cent of the nickel content of the contact has been converted into nickel sulfide, regenerating the contact so that it is predominantly in the formof nickel oxide and re-using the regenerated contact in the process.

Ll0. The process for desulfurizing a high boiling petroleum oil which comprises treating vapors thereof, in the presence of a low boiling hydrocarbon diluent, with a contact comprising a support and a nickeliferous reactant initially predominantly in the form of nickel oxide at a temperature in the range of 750 to 950 F. at a pressure above about 100 pounds per square inch gauge and in the presence of hydrogen, .absorbing sulfur from the vapors to form nickel sulde, terminating the treatment before a substantial amount of hydrogen sulfide appears in the treated vapors and before about 60 per cent of the nickel content of the contact has been converted into nickel sulfide, regenerating the contact so that it is predominantly in the form of nickel oxide and re-using the regenerated contact in the process.

11. The process for desulfurizing a high boiling petroleum oil which comprises treating vapors thereof, in the presence of steam, with :a contact comprising a support and a nickeliferous reactant initially predominantly in the form of nickel oxide at a temperature in the range of 750 to 950 F, at a pressure above about 100 pounds per square inch gauge and in the presence of hydrogen, absorbing sulfur from the vapors to form nickel suliide, terminating the treatment before a substantial amount of hydrogen sulfide appears in the treated vapors and before about 60 per cent of the nickel content of the contact has been converted into nickel sulfide, regenerating the contact so that it is predominantly in the form of nickel oxide and re-using the regenerated contact in the process.

12. The process for desulfurizing a high boil* ingpetroleum oil which comprises treating vapors thereof with a contact comprising a support and a nickelirerous reactant initially predominantly in the form of nickel oxide at a temperature in the range of 750 to 950 F. at a pressure above about 100 pounds per square inch gauge and in thepresence of hydrogen, absorbing sulfur from the Vapor to form nickel sulde, terminating the treatment before a substantial amount of hydrogen sulde appears in the treated vapors and before about 60 per cent of the nickel content of the contact has been converted into nickel sulde, regenerating the contact by passing an oxygen containing gas over it and re-using the regenerated contact in the process.

13. The process for desulfurizing a high boiling petroleum oil which comprises treating vapors thereof with a contact comprising a support and a nickeliferous reactant initially predominantly in the form of nickel oxide at a temperature in the range of 750 to 950 F. at a pressure above about 100 pounds per square inch gauge and in the presence of hydrogen, absorbing sulfur from the vapors to form nickel sulfide, terminating the treatment before a substantial amount of hydrogen suliide appears in the treated vapors and before about 50 per cent of the nickel content of the contact has been converted into nickel sulde, regenerating the contact by passing air over itat a temperature in the range between about 1000 and 1300" F. at a pressure in the range be tween about 0 and 500 p. s. i. g. and in the presence of a diluent gas having a ratio to air on a volume to volume basis of between 0 and 20 and f re-using the regenerated contact in the process.

wrLuAM A. HORNE. JAMES F. JUNG.

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

UNITED STATES PATENTS Number Name Date 1,955,297 Jennings Apr. 17, 1934v 2,037,792 Ipatieff Apr. 21, 1936 2,063,113 Morrell Dec. 8, 1936 2,171,009 Rostin et al Aug. 29, 1939 2,236,216 Lyman et al Mar. 25, 1941' 2,298,346 Corson et al Oct. 13, 1942 2,392,579 Cole Jan. 8, 1946 2,409,690 Nicholson et a1 Oct. 22, 1946 2,413,312 Cole Dec. 31, 1946 2,422,372 Smith et a1 June 17, 1947i 2,431,920 Cole Dec. 2, 1947 FOREIGN PATENTS Number Country Date Italy May 31, 1937

Claims (1)

1. THE PROCESS FOR DESULFURIZING A HIGH BOILING PETROLEUM OIL WHICH COMPRISES TREATING VAPORS THEREOF WITH A CONTACT COMPRISING A SUPPORT AND A NICKELIFEROUS REACTANT INITIALLY PREDOMINANTLY IN THE FORM OF NICLE OXIDE AT A TEMPERATURE IN THE RANGE OF 750* TO 950*F. AT A PRESSURE ABOVE ABOUT 100 POUNDS PER SQUARE INCH GUAGE AND IN THE PRESENCE OF HYDROGEN, ABSORBING SULFUR FROM THE VAPORS TO FORM NICKEL SULFIDE ON THE CONTACT, TERMINATING THE TREATMENT BEFORE A SUBSTNTIAL

Images