DE2013530A1 - Desulfurization of petroleum coke - Google Patents

Description

DR. BERG DIPLHNG. STAPF

8 MUNICH 2. HILBLESTRASSE 2O

Dr. Berg Dipl.-Ing. Stopf, 8 MOnchan 2, Hilblertrofl »20 Your reference Our reference Date L Ui Μ§ΓΖ 1970

Attorney's file 19 397 * M

Be / A

ESSO Research, and Engineering Company • linden, JF. J «(USA)

"Desulfurization of petroleum coke ¹¹

This invention relates to improvements in desulfurization of coke particles containing high percentages of sulfur In particular, the invention relates to desulfurization of High sulfur petroleum coke particles from plied coke or delayed coking processes in which

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coke particles are subjected to gasification treatment with steam at elevated temperatures and pressures.

The prior art methods of desulfurizing petroleum coke involve the combined treatment of coke, which involves treating coke with steam at high temperatures with the addition of hydrogen at pressures ranging from about 1 to about 5 atmospheres. In these known processes, it is typical to have a process with steam treatment followed by a hydrogen treatment at 650 to 925 ° C ( ^{1200-1700 0} P), whereby the sulfur content of coke from blow coke process, hereinafter referred to simply as blow coke, to about 4 wt. ^ is decreased. One of the major disadvantages of using these methods is the use of relatively expensive hydrogen to desulfurize black coke. In addition, the multiple treatments increase the costs involved.

Coking has the greatest benefit in increasing the quality of petroleum vacuum refinery residues Quality and pitches made from acidic crude oils with a high asphalt content. Such residues often contain high concentrations of sulfur, i.e. 3% by weight or more. In general is the sulfur content of the coke product from the Plied Coke or "Delayed Coking" processes is about two times as high as the sulfur content of the residue feed from which it is made will. The sulfur content of coke from acidic return

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can therefore be in a range as high as 5 to 8 # Sulfur or higher.

The high sulfur content of the coke product constitutes a major problem for its effective use. Many non-fuel or premium oil uses require a low sulfur coke of about or less than 4 wt% sulfur. When using coke for the production of certain metals, the sulfur content should be significantly below 4 % .

The conventional methods of removing sulfur from coke of conventional origin with gaseous reagents have heretofore generally not been satisfactory. The results are even lower when these methods are used with fluidized coke versus "delayed" coke or coal. It is due to dies.der fact that the Benandlun ^ sgase have to that contained in the coke particles bchwefel relatively low "access. Flieiikoks is having in its structure lamina U and may be about 50 to 100 one above the other lying ochienten of coke. It is therefore for a Heagens difficult to penetrate into more than a few outer layers.These difficulties in desulphurizing hot coke are further compounded by the higher than normal sulfur content of this coke from high sulfur petroleum feeds.

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The present invention overcomes the foregoing difficulties and disadvantages by providing an improved method for desulfurizing high sulfur petroleum coke using steam at elevated temperatures and pressures. In particular, in the present process is gasified petroleum coke with steam under elevated temperatures and pressures in part, if desired in the presence of a suitable catalyst such as, for example, IL, CO ,, thereby reducing the sulfur content of the petroleum coke to below about 1.5 wt. 1. " .

In accordance with an improved method of the present invention for lowering the sulfur content of petroleum coke, the coke is steamed at a temperature in the range of about 4-30 to about 137O ⁰ C (800-250 ⁰ F) and at pressures in the range of about 7 to about 211 ata (100-3000 psig) partially gasified, with the gasification of the coke being carried out to an extent of about 5 to about 50 wt. 96. The sulfur reduction is preferably carried out

in the unconverted coke to less than 1.5 wt. i »and ideally to less than 1.0 Gew.96 sulfur in the unconverted coke.

The reaction can be carried out in the presence of an alkali metal carbonate catalyst or another suitable steam coke catalyst. The partial gasification of the petroleum, Coke is best achieved by using larger

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Gas or steam velocities than 3.048 cm / sec. (O ₁ l ft / sec) used in either a plague or fluidized bed.

It has been found that when gasifying petroleum coke in the presence of a gasification catalyst, the alkali metal carbonates such as potassium carbonate (K ₂ OO,) and sodium carbonate (Na ₂ OCU) are most useful in practicing the invention. Of particular utility is K ₂ OO, in an amount in the range of up to 50% by weight, based on the coke. However, such amounts of K ₂ OQ- are economically inexpedient. It has therefore been found that a cost-balanced, excellent gasification can be achieved when K ₂ CO used in amounts ranging from about 1 to 25 wt.%. Most suitable amounts of K ₂ OQ in the practice of the invention are in the range of about 2 to about 10 weight percent based on the coke.

It was also found that other variable lactors can be changed to influence the gasification rate. One of the most important is the gas resp. Steam velocities greater than about 5 cm / sec. (0.1 ft./sec.) Should be. Preferably, the Gasge ^ speeds of 1.5 cm / sec. (0.05 ft./sec.) Up to approximately 60 cm / sec. (2.0 ft./sec.), But the most preferred range is 3.04-8 to 12.2 om / sec (0.1 to 0.4 ft./sec »).

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At the same time it is of importance, water loading rates to be used that are compatible with the gas velocities given above. Generally lies the rate of steam feed in the range of 0.1 up to about 20 w / w / h (Part by weight of water / part by weight Coke / btd.). At these speeds and under suitable Temperature and pressure conditions, as indicated below, make it possible to convert more than 25% of steam to reach. Most suitably, the steam feed rate should be in the range of 1 to about 8 W / w / h, depending on the temperature and pressure, under which the gasification takes place lie.

Good gasification and bchwefelentfernung from the .Rückstandkoks was the use of temperatures between 430 and 157O ⁰ C (800 - 25OO ° E) is reached. When catalysts are used, the temperatures are preferably in the range of about 430 to about 87O ⁰ G (800 to 1600 ⁰ F), while temperatures between about 870 to about 1090 ⁰ C (1600 2000 P) are hevorzugt without catalyst usually. Temperatures in the range from approximately 540 to approximately 820 ^° C. (1000 1500 i ¹ ) are particularly preferred when using a catalyst.

It has been found that at the temperatures given above, the petroleum coke up to about 110> o / iitd., Especially at Bridges ranging from about 14 to about 70 ata

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(200-1OQO psig), can be gasified · Within the preferred Range, the higher pressures are desirable due to the fact that such pressures involve the effort the subsequent compression of the by the into consideration reduce hydrogen formed in the coming reactions. There would therefore be pressures in the range of 14 to about 60 ate (200-850 psig) most suitable for practicing the invention with the upper ranges being particularly preferred.

The coke particle size depends on the conditions under which the petroleum coking takes place. The present proceedings can generally be used with flowing or "delayed" cokes in their commercially available form. If desired, the particle size can be reduced to the particular device conditions.

One of the most important factors in the present titanium sulphurisation process consists in the fact that the water supply is omitted. The addition of hydrogen tends to Reduce coke gasification rate, best reaction rates were achieved by being alone Steam in the range of the gas velocities given above and applying temperature and pressure conditions. To this Way it was found that in a gasification of flowing coke -from about 20 to 30; o 77 to 86. # sulfur in that

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Flow coke can be removed. This will be more detailed in the shown in the following example.

example 1

Using a plague bed reaction vessel charged with 33 g of "Billings Green" fluid coke, steam was supplied at 76O ⁰ C (HOO ⁰ P). The amount of steam supplied to the reaction vessel was approximately 1 wt. Water per wt. W coke per hour (w / w / h).

The treatment of the flowing coke with steam was carried out in this Run for three consecutive periods of time with an initial pressure of 21 ata (300 psig), then at atmospheric Pressure and then again at a pressure of 21 ata (300 psig). The exit gas was used to condense cooled by unconverted water and a sample of the dry gas collected at the end of each period and analyzed. The hydrogen sulfide content is below specified. In each case the drying gas contained the expected mixture of hydrogen, carbon monoxide, carbon dioxide and methane.

Period of gasified coke at the HpS content of the end of the period of time _Tr0ckenga8ea , j

(a) 21 ata

(300 psig) 10.5 0.83

(b) atmospheric 13.7 0.14

(c) 21 ata

(300 psig) 19.3 1.01

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Upon examination of the above, it appears that the removed from the coke and evolved into the product gas HpS amount at atmospheric pressure is less than at 21 ata (300 psig)

Examples 2 to 4

A Eestbett reaction vessel was in the same manner as in Example 1 above in turn with "Billings" -FIießkoks produced · The Pließkoks was ata (280 psig) with steam at 76o ⁰ O (HOO ⁰ I ¹⁾ and 19.7 partially gasified both with and without a gasification catalyst (ETr · 2 and 3 without catalyst) «The" Billings ¹¹ coke sample used in these processes contained 5.85% by weight of sulfur. The results of the three desulfurization processes are given below «

example ¥> gassing ψ catalyst * Sulfur content of
not gassed
Coke (? S) 2 23 0 1.4 3 23 0 1.3 '4 32 5 0.8

*) The catalyst was K ₂ CO, *

The results show that under these conditions sulfur is selectively gasified about 3 to 4 times as fast as carbon and that 80 to 90 $> sulfur is removed along with 18 to 27 # carbon.

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Example 5

The partial gasification of a sample of "Billings ^lf -i'ließkoks _f similar to the sample as used in Example 1, delivered at a pressure of 60 ata (850 psig) and at a temperature of 65O ⁰ C (1200 ⁰ P) a Reduction of the sulfur content of the remaining flowing coke from the original 5.7% by weight to 0.2% by weight. The treatment of the coke with steam in the presence of a KgCO ^ catalyst produced a 33% gasification of the coke.

Example 6

A fixed bed reactor was prepared as in Example 1 with a "Billings ^ll -Fließkoksprobe and a KpCO, - prepared catalyst, the coke was filled with vapor at 760 ⁰ C..

P), but partially gasified at atmospheric pressure. The contact time has been significantly increased compared to the time usually used, ie compared to the time when pressures higher than atmospheric pressures are used. This was done in order to achieve up to about 66 fiige gasification of the coke. The remaining coke had a residual sulfur content of 3.05% by weight. This process explains the enormous effect of the implementation, the gasification reaction under pressure, as can also be seen from the other processes.

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Example 7

In a fluidized bed, 600 kg (1100 lbs.) 'Of the 5 _f 3 Gew.fi contained sulfur and 10 wt. ^ KpCO, was added 11 hrs. At 65O ⁰ C (120O ⁰ F) and H ata (200 psig ) with steam at a rate of 0.2 w / w / h. at a linear gas velocity of 9 »1 cm / sec. (0.3 ft./sec.) · The coke was originally made from a high vanadium Caribbean residue. After the above treatment, it was found that the coke has been gasified to 35 i * and the remaining coke had a sulfur content of 1.1 Gew.?6 residue.

Example 8

Using a plague bed type reaction vessel, 454 kg (1000 lbs.) Of delayed coke made from Caribbean residues and containing 5% sulfur was treated in the same manner as the blown coke sample in Example 3, that is, without a catalyst at 760 ⁰ C (HOO ⁰ P) and 19.7 ata (280 psig). Gasification was over 30 #, while the remaining coke had a residual sulfur content of less than 1.5 wt, #.

The method according to the invention includes the use a suitable gasification catalyst such as potassium carbonate. The catalyst can easily with the petroleum coke before it Feed to the reaction vessel. After his-

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The catalyst is of conventional use Procedure removable. However, there may be a slight overall loss of catalyst.

The importance of catalyst use can be inferred from the fact that 'the removal of metals, especially vanadium, possible by simple water washing is when the catalyst verx in the desulfurization step

m is turned. In general, such a procedure would involve charging the coke catalyst mixture into a pressure reaction vessel, the footprints on the above mentioned level at a temperature of about 538-816 ⁰ C (1000 1500 ⁰ F) and the treatment with steam. The resulting gas is discharged, the water is recovered and the hydrogen is purified. The desulphurized coke is removed and washed with water, which removes vanadium and most other metals.

^ material is to be desulfurized, this means that one approximately 0.36 wt. 96 vanadium removed, this removal is again an object of the present invention.

If no catalyst is used, the desulfurization requires a temperature of about 820 to about 1370 ⁰ C (1500 - 250o ⁰ F), preferably from 870 to 1090 ⁰ C (1600 ⁰ 2000 F). One of the disadvantages of not using a catalyst is that metal removal by the water washing step is not possible.

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Both processes, the catalyzed and non-catalyzed, can be used in most conventional reaction vessels that .are suitable for desulphurization. in the in general, reaction vessels of the fluidized bed or moving bed type are suitable. However, others are also suitable suitable contact means acceptable, including reaction vessels, which are designed for step work processes.

It should be noted that the present invention in is also suitable for desulphurisation of shale oil and tar sands products compatible with steam treatment processes o

The vapor supply to the reaction vessel is pretty in one wide range in which one can achieve satisfactory 'desulfurization achieved, variable. Steam can be used in an amount ranging from about 0.05 to about 20.0 w / w / hr. are fed. A more preferred range is from 0.1 up to about 10.0 w / w / hour with best results

with a steam supply in the range of 0.2 to 4 w / w / Hours. can be obtained. . .

These steam additions, particularly in the more preferred ranges at the preferred temperatures and pressures, provide a coke feed rate of up to about 100 < per hour, of course, higher gasification rates allow gasification to be achieved in a shorter time,

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(which reduces the contact time of the coke intended for desulphurization ) · Therefore, depending on the gasification ratios chosen, the solids contact times are in the range from approximately 5 minutes up to approximately
6 hours or more. Preferably, the contaminant contact time should be in the range of 15 minutes to about 2 hours.

ψ Taking away the fact that the present process supplies hydrogen relatively cheaply, one obtains a desulphurized coke which is extremely good for making iron in
Is suitable for blast furnaces. Once the vanadium is extracted from the desulfurized coke, it is useful for making high quality aluminum.

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Claims (1)

Claim O ·) A coke desulfurization process characterized in that coke is treated with steam at a temperature in the range of about 430 to 137O ⁰ C (800-250O ⁰ F) at a pressure between about 7 and about 210 ata (100-3Q00 psig), whereby the coke from about 5 to about 50 sew. is gasified and the sulfur content of the unconverted coke is reduced to less than about 1.5% by weight based on the remaining coke. 2. The method according to claim 1 characterized in that the coke in the presence of a suitable catalyst at a temperature between about 82o and 4-30 ⁰ C is desulfurized (800 to 1500 ⁰ P). 3. Process according to claim 2, characterized in that the catalyst is potassium carbonate (K ₂ CO,) and is present in an amount in the range from about 1 to 50% by weight, based on the reaction charge. 4. The method according to claim 2, characterized in that the catalyst potassium carbonate (K ₂ CO,) and in the reaction in a small amount in the range of 1 to 25 wt. ^, Based on the reaction charge, is present. Q098A0 / 1486 5. The method according to any one of claims 1 to 4, characterized in that that the unconverted, desulphurized coke is then subjected to a water wash and im substantially all of the metals in it are removed. 6. The method according to claim 1, characterized in that the coke without a catalyst at a temperature in the range of about 816 to 1093 ° C (1500 to 2000 ⁰ E) and at a pressure in the range of about 14 to about ^ O ata ( 200 to 1000 psig) is desulfurized, reducing the sulfur content of the unconverted coke to less than 1.5 wt.76 based on the remaining coke. 7. A method in accordance with claim 1 characterized in that (a Fließkoksverfahrens product) a fluid coke used as coke and this with steam in a fluidized bed at a temperature in Keaktionsgefäß .Bereich of 538 to about 760 ⁰ C (1000-1400 ⁰ F) and is treated psig (200 and 800) at a pressure between about 14 and 49 ata, the fluid coke was mixed previously with from about 1 to about 20 wt.% K ₂ CO, catalyst, one then the unconverted desulfurized coke in Treated a water washing stage and removed substantially all of the metals therefrom and treated the gas products for .Reinigung the hydrogen contained therein. 0098 AO / I486 8o method according to one of claims 1 to 5, characterized in that that .the pressure between about H and about 70 ata (200-1000 psig) * 9. Coke desulfurization process, essentially as here
under "special reference to one of the examples. 10. Desulphurized coke, provided that it has been produced by a procedure in accordance with any one of claims 1 to 9 was produced. 009840/1486