CA1155414A - Process for calcining and desulfurizing petroleum coke - Google Patents
Process for calcining and desulfurizing petroleum cokeInfo
- Publication number
- CA1155414A CA1155414A CA000395619A CA395619A CA1155414A CA 1155414 A CA1155414 A CA 1155414A CA 000395619 A CA000395619 A CA 000395619A CA 395619 A CA395619 A CA 395619A CA 1155414 A CA1155414 A CA 1155414A
- Authority
- CA
- Canada
- Prior art keywords
- coke
- range
- sulfur content
- period
- heating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000000034 method Methods 0.000 title claims description 44
- 239000002006 petroleum coke Substances 0.000 title claims description 17
- 238000001354 calcination Methods 0.000 title description 8
- 230000003009 desulfurizing effect Effects 0.000 title description 2
- 239000000571 coke Substances 0.000 claims abstract description 99
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 56
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 56
- 239000011593 sulfur Substances 0.000 claims abstract description 56
- 238000010438 heat treatment Methods 0.000 claims abstract description 28
- 239000012298 atmosphere Substances 0.000 claims abstract description 22
- 239000001257 hydrogen Substances 0.000 claims abstract description 17
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 17
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 15
- 230000001590 oxidative effect Effects 0.000 claims abstract description 15
- 239000002245 particle Substances 0.000 claims description 17
- 239000002008 calcined petroleum coke Substances 0.000 claims description 9
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 6
- 238000004939 coking Methods 0.000 claims description 6
- 230000003111 delayed effect Effects 0.000 claims description 6
- 229910052760 oxygen Inorganic materials 0.000 claims description 6
- 239000001301 oxygen Substances 0.000 claims description 6
- 239000011329 calcined coke Substances 0.000 abstract description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 238000006477 desulfuration reaction Methods 0.000 description 4
- 230000023556 desulfurization Effects 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- DTAFLBZLAZYRDX-UHFFFAOYSA-N OOOOOO Chemical compound OOOOOO DTAFLBZLAZYRDX-UHFFFAOYSA-N 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000003085 diluting agent Substances 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 238000007669 thermal treatment Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L9/00—Treating solid fuels to improve their combustion
- C10L9/02—Treating solid fuels to improve their combustion by chemical means
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Coke Industry (AREA)
- Carbon And Carbon Compounds (AREA)
- Solid Fuels And Fuel-Associated Substances (AREA)
Abstract
A B S T R A C T
Low sulfur calcined coke having an adequate density value for industrial consumers is produced from high sulfur raw coke by treating the coke in three con-secutive heating stages under controlled conditions, the first stage being carried out in an oxidizing atmosphere and the second stage being in the presence of added hydrogen.
Low sulfur calcined coke having an adequate density value for industrial consumers is produced from high sulfur raw coke by treating the coke in three con-secutive heating stages under controlled conditions, the first stage being carried out in an oxidizing atmosphere and the second stage being in the presence of added hydrogen.
Description
1155~
~ROCESS FOR CALCI~ING AND DESULFURIZING PETROLEUM COKE
The invention relates generally to a pxocess for improving the properties of raw or "green" cokes obtained by kr.own proce~ses from materials of petroleum orlgin and 5 particularly to a process for calcining and desulfurlzing such cokes to provide a product having acceptable sulfur conten~ with satisfactory density characteristics.
Industrial petroleum coke is manufactured by methods well known in the art, the major method being delayed coking.
10 Unfortunately, many petroleum cokes produced by this and other known methods contain appreciable amounts of sulfur, and cannot be directly utilized in the fabrication o some carbon products due to this impurity, Aluminum producers, ~or example, ~he largest consumer in total quantity of 15 calcined petroleum coke, xequire low sulfur coke to satisfy environmental xegulations. These producers currently specify that the ~ulfur content of these cokes must be at a level o no more than about 2.5 wt,% to be acceptable for use in the fabrication of anodes for aluminum reduction cells.
Raw petroleum coke fox industrial pw~ses is con-ventionally calcined at tempertures in the range of about 1150-1300C. by me~hads well known in the art to remove substantially all of the volatile matter content of the coke and to provide increased density and conductivity therefor.
25 It is known that the customaxy methods utilized for petroleum coke calcinatlon are, in and of themselves, not adequate to bring about desulfurization of the coke without deterioration of other important coke properties.
~:~554~4 A physical property of calcined petroleum coke recently recognized by those skilled in the art as belng useful in predicting the apparent density, strength, and consumption rate o~ baked carbon anodes made ~rom that coke S in aluminum (Hall) cells is vibrated bulk density (VBD).
A method for determining this property generally comprises placing a 100~0 gram sample of the calcined coke particles sized between 300 and 850 microns (-20/~48 mesh Tyler Screen Scale) in a 2S0 cc graduated cylinder moun~ed in a jogger 10 (shaker) unit and vibrating the cylinder for 5 minutes at a predetermined jogging rate at which maximum particle com-paction occurs. The volume of the compacted coke particles is recorded and the VBD, expressed in g/100 cc, is calculated as ~ollows:
VBD = (A/B) X 100 where:
A = sample weight in grams B = compacted volume in cubic centimeters.
The particle size of the coke sample used in the VBD deter-20 mination is approximately midpoint in the conventional anode aggregate particle size distribution.
It has been found that a VBD value for calcined coke of at least ahout 78 g/100 cc is necessary to provide acceptable quality for u e in anode production.
It is known in the art that the temperatures at whicn calcina~ion of high sulfur raw petroleum coke is con-ventionally carried out are not sufficient to reduce the coke's sulfur level to a value acceptable to consumers.
One method known for desulfuriæing xaw coke comprise~
30 directly heating the coke in a single stage to a temperature above about 1500C. in a rotary kiln or t~e like. Experience has taught that while this procedure effectively reduces the coke's sul~ur content, the VBD and other physical properties are substantially deteriorated during the heat treatment 35 process, as compared to coke pxoperties after calcination at conventional tempexatures.
U.S. Pat. No. 4,160,814 to ~ardin et al. provides a li55414 two stage process for calcining and thermally desul~urizing raw petroleum coke w~thout lowering its bulk density (BD), as defined below, comprising heating the coke at 490C. to 850C. for 30 to 60 minutes while retaining at least 30 wt.
5 of the coke's volatile content, then heating the partially devolatillzed coke at a temperature of at least 1500~C. for 30 to 70 minutes to calcine and desulfurize the coke. The BD
value referred to in the patent is the weight per unit volume of the coke particles, and i9 determined by transferring a 10 weighed sample of the coke, having a particle size elther in a range of 3.36 to 4.76 mm (-4/+6 mesh Tyler Screen Scale) or Run of Kiln (ROK) size, into a graduated container and calculating the BD from the displaced volume and sample weight. While the process provided in this patent advanced 15 the art of coke desulfurization over known processes by provlding retention of normal bulk density values, it was learned that the coke product exhibited lowered VBD pro-perties compared to conventionally calcined coke. The lowered VBD value indicates a decreased strength and increased 20 consumption of anodes made from coke produced accordlng to this patent, compared to coke calcined by conventional methods without desulfurization.
Generally, the present invention relates to a three-stage process for producing calcined petroleum coke 25 having`a sulfur content in the range of about 1.5 wt. % to about 2.5 wt. ~ and a VBD of at least about 78 g/100 cc from raw petroleu,m coke having a sulfur content greater than ahout 2.5 wt. ~ and a volatile content of at least about 7 wt.
~ comprising: (a) heating the coke at a temperature in the 30 range of about 250C. to about 450C. in an oxidizing atmosphere ~or no less than about 0.5 hour, preferably not over two hours; (b) heating the oxidized coke at a temperature in ~he range of about 600C. to about 800C. in an atmo~phere containing added hydroyen for a period of time sufficient to 35 reduce the sulfur content of the coke to a level such that no ~ore than about l.$ wt. ~ of sulfur, preferably about 0.3 to about 1.0 wt. ~ required to be removed in the stage (c~;
1:~554~4 and (c) heatlng the partially desulfurized coke at a tem-perature in the range of about 1350C. to abou~ 1600C. ln the absence of added hydrogen, preferably in an inert or reducing atmosphere, for a period of time sufficlent to re-$ duce the sulfur content of the coke to within the range ofabout 1.5 to about 2.5 wt. %.
Preferably, the treatment stages of the invention ; are controllad to provide a final coke yield of no less than about 80 wt. %, on a dried feed coke basis. When using air 10 to supply oxygen during the first stage, it is preferable to prevent excessive burning by utilizing nitrogen or the like as a diluent to provide an oxidizing atmosphere having about 6 to about 14 wt. % oxygen.
It is critical in this process that the desulfur-15 ization of the coke is not allowed to proceed below about1.5 wt. %, preferably about 1.8 wt. %, as further sulur reduction results in an unacceptably low VBD value for the calcined coke product.
The total coke processing time necessary for carry-20 ing out the process of the invention is generally not o~erabout 8 hours and usually does not require more than about 6 hours, the elapsed time depending on the sulfur content, volatile content and particle size of the raw coke feed material. For example, a process for producing a calcined 25 petroleum coke having a sulfur content of about 1.8 to about
~ROCESS FOR CALCI~ING AND DESULFURIZING PETROLEUM COKE
The invention relates generally to a pxocess for improving the properties of raw or "green" cokes obtained by kr.own proce~ses from materials of petroleum orlgin and 5 particularly to a process for calcining and desulfurlzing such cokes to provide a product having acceptable sulfur conten~ with satisfactory density characteristics.
Industrial petroleum coke is manufactured by methods well known in the art, the major method being delayed coking.
10 Unfortunately, many petroleum cokes produced by this and other known methods contain appreciable amounts of sulfur, and cannot be directly utilized in the fabrication o some carbon products due to this impurity, Aluminum producers, ~or example, ~he largest consumer in total quantity of 15 calcined petroleum coke, xequire low sulfur coke to satisfy environmental xegulations. These producers currently specify that the ~ulfur content of these cokes must be at a level o no more than about 2.5 wt,% to be acceptable for use in the fabrication of anodes for aluminum reduction cells.
Raw petroleum coke fox industrial pw~ses is con-ventionally calcined at tempertures in the range of about 1150-1300C. by me~hads well known in the art to remove substantially all of the volatile matter content of the coke and to provide increased density and conductivity therefor.
25 It is known that the customaxy methods utilized for petroleum coke calcinatlon are, in and of themselves, not adequate to bring about desulfurization of the coke without deterioration of other important coke properties.
~:~554~4 A physical property of calcined petroleum coke recently recognized by those skilled in the art as belng useful in predicting the apparent density, strength, and consumption rate o~ baked carbon anodes made ~rom that coke S in aluminum (Hall) cells is vibrated bulk density (VBD).
A method for determining this property generally comprises placing a 100~0 gram sample of the calcined coke particles sized between 300 and 850 microns (-20/~48 mesh Tyler Screen Scale) in a 2S0 cc graduated cylinder moun~ed in a jogger 10 (shaker) unit and vibrating the cylinder for 5 minutes at a predetermined jogging rate at which maximum particle com-paction occurs. The volume of the compacted coke particles is recorded and the VBD, expressed in g/100 cc, is calculated as ~ollows:
VBD = (A/B) X 100 where:
A = sample weight in grams B = compacted volume in cubic centimeters.
The particle size of the coke sample used in the VBD deter-20 mination is approximately midpoint in the conventional anode aggregate particle size distribution.
It has been found that a VBD value for calcined coke of at least ahout 78 g/100 cc is necessary to provide acceptable quality for u e in anode production.
It is known in the art that the temperatures at whicn calcina~ion of high sulfur raw petroleum coke is con-ventionally carried out are not sufficient to reduce the coke's sulfur level to a value acceptable to consumers.
One method known for desulfuriæing xaw coke comprise~
30 directly heating the coke in a single stage to a temperature above about 1500C. in a rotary kiln or t~e like. Experience has taught that while this procedure effectively reduces the coke's sul~ur content, the VBD and other physical properties are substantially deteriorated during the heat treatment 35 process, as compared to coke pxoperties after calcination at conventional tempexatures.
U.S. Pat. No. 4,160,814 to ~ardin et al. provides a li55414 two stage process for calcining and thermally desul~urizing raw petroleum coke w~thout lowering its bulk density (BD), as defined below, comprising heating the coke at 490C. to 850C. for 30 to 60 minutes while retaining at least 30 wt.
5 of the coke's volatile content, then heating the partially devolatillzed coke at a temperature of at least 1500~C. for 30 to 70 minutes to calcine and desulfurize the coke. The BD
value referred to in the patent is the weight per unit volume of the coke particles, and i9 determined by transferring a 10 weighed sample of the coke, having a particle size elther in a range of 3.36 to 4.76 mm (-4/+6 mesh Tyler Screen Scale) or Run of Kiln (ROK) size, into a graduated container and calculating the BD from the displaced volume and sample weight. While the process provided in this patent advanced 15 the art of coke desulfurization over known processes by provlding retention of normal bulk density values, it was learned that the coke product exhibited lowered VBD pro-perties compared to conventionally calcined coke. The lowered VBD value indicates a decreased strength and increased 20 consumption of anodes made from coke produced accordlng to this patent, compared to coke calcined by conventional methods without desulfurization.
Generally, the present invention relates to a three-stage process for producing calcined petroleum coke 25 having`a sulfur content in the range of about 1.5 wt. % to about 2.5 wt. ~ and a VBD of at least about 78 g/100 cc from raw petroleu,m coke having a sulfur content greater than ahout 2.5 wt. ~ and a volatile content of at least about 7 wt.
~ comprising: (a) heating the coke at a temperature in the 30 range of about 250C. to about 450C. in an oxidizing atmosphere ~or no less than about 0.5 hour, preferably not over two hours; (b) heating the oxidized coke at a temperature in ~he range of about 600C. to about 800C. in an atmo~phere containing added hydroyen for a period of time sufficient to 35 reduce the sulfur content of the coke to a level such that no ~ore than about l.$ wt. ~ of sulfur, preferably about 0.3 to about 1.0 wt. ~ required to be removed in the stage (c~;
1:~554~4 and (c) heatlng the partially desulfurized coke at a tem-perature in the range of about 1350C. to abou~ 1600C. ln the absence of added hydrogen, preferably in an inert or reducing atmosphere, for a period of time sufficlent to re-$ duce the sulfur content of the coke to within the range ofabout 1.5 to about 2.5 wt. %.
Preferably, the treatment stages of the invention ; are controllad to provide a final coke yield of no less than about 80 wt. %, on a dried feed coke basis. When using air 10 to supply oxygen during the first stage, it is preferable to prevent excessive burning by utilizing nitrogen or the like as a diluent to provide an oxidizing atmosphere having about 6 to about 14 wt. % oxygen.
It is critical in this process that the desulfur-15 ization of the coke is not allowed to proceed below about1.5 wt. %, preferably about 1.8 wt. %, as further sulur reduction results in an unacceptably low VBD value for the calcined coke product.
The total coke processing time necessary for carry-20 ing out the process of the invention is generally not o~erabout 8 hours and usually does not require more than about 6 hours, the elapsed time depending on the sulfur content, volatile content and particle size of the raw coke feed material. For example, a process for producing a calcined 25 petroleum coke having a sulfur content of about 1.8 to about
2,5 wt. ~ and a VBD of at least about 7B g/100 cc from a raw coke havlng a sulfur content in the range of about 3.5 to about 5.0 wt. % and a volatile matter content in the range of about 9 to about 14 wt. % generally require~ an oxidation 30 treatment period in the range of about 1 hour to about 2 hours in s~age (a) of the process of the invention; about 2 hours to about 6 hours in hydrodesulfurization stage (b) to produce a coke having a sulfur co~tent in the range of about 2.8 to about 3.3 wt. %, 6 hours being the preferred treatment period 35 for an exceptionally low sulfur product coke with an acceptable ~3D value; and about 0.5 hour to about 1.5 hours, preferably about 1. O hour, in thermal treatment stage (c) to produce a 1 ~ 5 5 4 1 4 calcined coke product having a sulfur content in the range of about 1,8 to about 2.5 wt. %. The time required for hydrodesul~urization stage (b) can be shortened signiflcantly by utilizing a small particle size feed coke, e.g., below 5 150 microns (~lO0 mesh Tyler Screen Scale).
The optimum conditions for each stage of the inven-tion vary according to the characteristics of the partlcular coke being treated. The individual treatment phases can be carried out using any known heating apparatus, such as lO rotary kilns, rotary or multiple hearth furnaces or the like.
Minor modification of the selected heating unit may be necessary to provide the appropriate atmosphere required for the oxidation and hydrodesulfurization stages.
The preferred embodiment of the invention will now 15 be described in non-limiting Example A. Additlonal examples are provided to illustrate additional embodiments. In view ~f the sulfur and volatile contents of the coke used ln the examples, the temperatures and heating periods for the coke calcination/desulfurization process were selected to provide 20 a coke sul~ur content of 2~8 to 3.3 wt. % after the hydrodesulfurization treatment and a final coke product having a sulfur content of 1.8 to 2.5 wt, %.
Example A
The coke employed in this example was a "regular"
25 raw petroleum coke, also known in the art as sponge coke, produced from reduced crude feadstock by the conventional delayed coking process. This raw coke had a sulfur content of 4.4 wt. % and a volatile content of lO.S wt. %. The particle size distribution of the coke is shown below.
The optimum conditions for each stage of the inven-tion vary according to the characteristics of the partlcular coke being treated. The individual treatment phases can be carried out using any known heating apparatus, such as lO rotary kilns, rotary or multiple hearth furnaces or the like.
Minor modification of the selected heating unit may be necessary to provide the appropriate atmosphere required for the oxidation and hydrodesulfurization stages.
The preferred embodiment of the invention will now 15 be described in non-limiting Example A. Additlonal examples are provided to illustrate additional embodiments. In view ~f the sulfur and volatile contents of the coke used ln the examples, the temperatures and heating periods for the coke calcination/desulfurization process were selected to provide 20 a coke sul~ur content of 2~8 to 3.3 wt. % after the hydrodesulfurization treatment and a final coke product having a sulfur content of 1.8 to 2.5 wt, %.
Example A
The coke employed in this example was a "regular"
25 raw petroleum coke, also known in the art as sponge coke, produced from reduced crude feadstock by the conventional delayed coking process. This raw coke had a sulfur content of 4.4 wt. % and a volatile content of lO.S wt. %. The particle size distribution of the coke is shown below.
3~ Sieve Size, mm Cumulative Wt.
6.73 19.6 3.36 39.5 0.84 72.0 0.30 86.8 0,21 89.9 0.15 92.3 7.7 Wt. ~ of the coke had a particle size below 0.15 mm.
115~
A 460 gram sample of the raw coke was charged into a 5~7 cm diameter tube positioned in a tube ~urnace. Air diluted with nitrogen to produce a gas having about 6.7%
oxygen was passed through the sample at a rate of about 2 5 liters/minute via a perforated closure in the tube and the fuxnace was rapidly heated to a temperature of 350C. The sample was treated in this manner for about 1 hour. ~fter puxging the tube with nitrogen to eliminate the oxidizing gas ~rom the sample, a hydrogen flow was passed through the 10 sample at approximately the same rate as the oxidizing gas.
The furnace tempera~ure was rapidly increased to 650~C. and held for about 6 hours to reduce the coke's qulfur content to 3.0 wt. %. The tube was then removed from the furnace and the coke sample was transferred to a tray which was placed in 15 a resistance heated graphite tube furnace having a nitrogen atmosphere and preheated to 1400C. The sample was hea~ed at this temperature for about 1 hour. The calcined coke product had a sulfur conten~ of 2.1 wt. % and a VBD value of 81 g/100 cc, and the coke yield Was 84.8 wt. % (dried ~eed coke basis).
For comparison, samples of the same raw coke having the same particle size distribution were calcined by known methods. The sulfur and VBD values of each product, and those of the calcined coke produced according to the process of the in~ention, are presented below.
Treatment Sulfur V~D
Process Temp_rature(s) C. wt. %g/100 cc St'd Calcination 1300 (0.5 hr) 3.9 85 one Stage High1400 (1 hr) 1.9 70 Temperature Calcination Two Stage High650/1400 1.9 73 Temperature(1 hr/l hr) Calcination According To~The 350/650/1400 2.1 81 In~ention(1 hr/6 hr/l hr) 1~ 554 1 4 : -7-Examples B-G
.
: The samples employed in the examples shown in the ' table below were taken from the same raw coke described above, with the same particle size distribution. The treat-5 ment apparatus and general procedure, including the flow .~ rates of ~he oxidizing gas and hydrogen, were about the same r~ as that used in Example A. The sample weights were in the ~ range of 400 to 465 grams.
:
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1:~554~4 g The data indicate that the process of the inventlon ' is an effective method whereby raw petroleum coke of the type defined can be treated to produce a calcined coke with both sulfur content and VBD values currently acceptable to 5 industrial consumers.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing 10 from the scope and spirit thereof, and, therefore, the inven-tion is not intended to be limited except as indicated in the appended claims.
6.73 19.6 3.36 39.5 0.84 72.0 0.30 86.8 0,21 89.9 0.15 92.3 7.7 Wt. ~ of the coke had a particle size below 0.15 mm.
115~
A 460 gram sample of the raw coke was charged into a 5~7 cm diameter tube positioned in a tube ~urnace. Air diluted with nitrogen to produce a gas having about 6.7%
oxygen was passed through the sample at a rate of about 2 5 liters/minute via a perforated closure in the tube and the fuxnace was rapidly heated to a temperature of 350C. The sample was treated in this manner for about 1 hour. ~fter puxging the tube with nitrogen to eliminate the oxidizing gas ~rom the sample, a hydrogen flow was passed through the 10 sample at approximately the same rate as the oxidizing gas.
The furnace tempera~ure was rapidly increased to 650~C. and held for about 6 hours to reduce the coke's qulfur content to 3.0 wt. %. The tube was then removed from the furnace and the coke sample was transferred to a tray which was placed in 15 a resistance heated graphite tube furnace having a nitrogen atmosphere and preheated to 1400C. The sample was hea~ed at this temperature for about 1 hour. The calcined coke product had a sulfur conten~ of 2.1 wt. % and a VBD value of 81 g/100 cc, and the coke yield Was 84.8 wt. % (dried ~eed coke basis).
For comparison, samples of the same raw coke having the same particle size distribution were calcined by known methods. The sulfur and VBD values of each product, and those of the calcined coke produced according to the process of the in~ention, are presented below.
Treatment Sulfur V~D
Process Temp_rature(s) C. wt. %g/100 cc St'd Calcination 1300 (0.5 hr) 3.9 85 one Stage High1400 (1 hr) 1.9 70 Temperature Calcination Two Stage High650/1400 1.9 73 Temperature(1 hr/l hr) Calcination According To~The 350/650/1400 2.1 81 In~ention(1 hr/6 hr/l hr) 1~ 554 1 4 : -7-Examples B-G
.
: The samples employed in the examples shown in the ' table below were taken from the same raw coke described above, with the same particle size distribution. The treat-5 ment apparatus and general procedure, including the flow .~ rates of ~he oxidizing gas and hydrogen, were about the same r~ as that used in Example A. The sample weights were in the ~ range of 400 to 465 grams.
:
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.: :
1:~554~4 g The data indicate that the process of the inventlon ' is an effective method whereby raw petroleum coke of the type defined can be treated to produce a calcined coke with both sulfur content and VBD values currently acceptable to 5 industrial consumers.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing 10 from the scope and spirit thereof, and, therefore, the inven-tion is not intended to be limited except as indicated in the appended claims.
Claims (14)
1. A three-stage process for producing calcined petroleum coke having a sulfur content in the range of about 1.5 to about 2.5 wt. % and a vibrated bulk density of at least about 78 g/100 cc from raw petroleum coke having a sulfur content greater than about 2.5 wt. % and a volatile content of at least about 7 wt. % which comprises:
(a) heating the coke at a temperature in the range of about 250°C. to about 450°C. in an oxidizing atmosphere for a period no less than about 0.5 hour;
(b) heating the oxidized coke at a temperature in the range of about 600°C. to about 800°C. in an atmosphere containing added hydrogen for a period of time sufficient to reduce the sulfur content of said coke to a level such that no more than about l.5 wt. % of sulfur is required to be removed in the final stage; and (c) heating the partially desulfurized coke at a temperature in the range of about 1350°C. to about 1600°C.
in the absence of added hydrogen for a period of time suf-ficient to reduce the sulfur content of the coke to within the range of about l.5 to about 2.5 wt. %.
(a) heating the coke at a temperature in the range of about 250°C. to about 450°C. in an oxidizing atmosphere for a period no less than about 0.5 hour;
(b) heating the oxidized coke at a temperature in the range of about 600°C. to about 800°C. in an atmosphere containing added hydrogen for a period of time sufficient to reduce the sulfur content of said coke to a level such that no more than about l.5 wt. % of sulfur is required to be removed in the final stage; and (c) heating the partially desulfurized coke at a temperature in the range of about 1350°C. to about 1600°C.
in the absence of added hydrogen for a period of time suf-ficient to reduce the sulfur content of the coke to within the range of about l.5 to about 2.5 wt. %.
2. The process of claim 1, wherein the oxidized coke is heated in the range of about 600°C. to about 800°C. in an atmosphere containing added hydyogen for a period of time sufficient to reduce the sulfur content of said coke to a level such that about 0.3 to about 1.0 wt. % of sulfur is required to be removed in the final stage.
3. A three-stage process for producing calcined petroleum coke having a sulfur content in the range of about 1.8 to about 2.5 wt. % and a vibrated bulk density of at least about 78 g/100 cc from raw petroleum coke having a sulfur content in the range of about 3.5 to about 5.0 wt. %
and a volatile content in the range of about 9 to about 14 wt. % which comprises:
(a) heating the coke at a temperature in the range of about 250°C, to about 450°C. in an oxidizing atmosphere for a period in the range of about l hour to about 2 hours;
(b) heating the oxidized coke at a temperature in the range of about 600°C. to about 800°C. for a period of time of about 2 hours to about 6 hours in an atmosphere containing added hydrogen such that the sulfur content of said coke is reduced to a level in the range of about 208 to about 3.3 wt. %; and c) heating the partially desulfurized coke at a temperature in the range of about 1350°C. to about 1600°C.
in the absence of added hydrogen for a period of time of about 0.5 hour to about 1.5 hours such that the sulfur content of the coke is reduced to a level of about 1.8 to about 2.5 wt. %.
and a volatile content in the range of about 9 to about 14 wt. % which comprises:
(a) heating the coke at a temperature in the range of about 250°C, to about 450°C. in an oxidizing atmosphere for a period in the range of about l hour to about 2 hours;
(b) heating the oxidized coke at a temperature in the range of about 600°C. to about 800°C. for a period of time of about 2 hours to about 6 hours in an atmosphere containing added hydrogen such that the sulfur content of said coke is reduced to a level in the range of about 208 to about 3.3 wt. %; and c) heating the partially desulfurized coke at a temperature in the range of about 1350°C. to about 1600°C.
in the absence of added hydrogen for a period of time of about 0.5 hour to about 1.5 hours such that the sulfur content of the coke is reduced to a level of about 1.8 to about 2.5 wt. %.
4. The process of claims 1,2 or 3, wherein the oxidizing atmosphere consists of about 6 to about 14 wt. %
oxygen. -
oxygen. -
5. The process of claims 1,2 or 3, wherein the final coke yield is no less than about 80 wt. % on a dried feed coke basis.
6. A three-stage process for producing calcined petroleum coke having a sulfur content in the range of about 1.5-to about 2.5 wt.% and a vibrated bulk density of at least about 78 g/lO0 cc from raw petroleum coke produced by the delayed coking process having a sulfur content greater than about 2.5 wt, %, a volatile content of at least about 7 wt. % and a particle size distribution of at least about 39 wt. % greater than 3.36 mm which comprises:
(a) heating the coke at a temperature in the range of about 250°C. to about 450°C. in an oxidizing atmosphere for a period no less than about 0.5 hour;
(b) heating the oxidized coke at a temperature in the range of about 600°C. to about 800°C. in an atmos-phere containing added hydrogen for a period of time sufficient to reduce the sulfur content of said coke to a level such that no more than about 1.5 wt. % of sulfur is required to be removed in the final stage; and (c) heating the partially desulfurized coke at a temperature in the range of about: 1350°C. to about 1600°C. in the absence of added hydrogen for a period of time sufficient to reduce the sulfur content of the coke to within the range of about 1.5 to about 2 5 wt. %.
(a) heating the coke at a temperature in the range of about 250°C. to about 450°C. in an oxidizing atmosphere for a period no less than about 0.5 hour;
(b) heating the oxidized coke at a temperature in the range of about 600°C. to about 800°C. in an atmos-phere containing added hydrogen for a period of time sufficient to reduce the sulfur content of said coke to a level such that no more than about 1.5 wt. % of sulfur is required to be removed in the final stage; and (c) heating the partially desulfurized coke at a temperature in the range of about: 1350°C. to about 1600°C. in the absence of added hydrogen for a period of time sufficient to reduce the sulfur content of the coke to within the range of about 1.5 to about 2 5 wt. %.
7. The process of claim 6 wherein the oxidized coke is heated in the range of about 600°C. to about 800°C.
in an atmosphere containing added hydrogen for a period of time sufficient to reduce the sulfur content of said coke to a level such that about 0.3 to about 1.0 wt. %
of sulfur is required to be removed in the final stage.
in an atmosphere containing added hydrogen for a period of time sufficient to reduce the sulfur content of said coke to a level such that about 0.3 to about 1.0 wt. %
of sulfur is required to be removed in the final stage.
8. A three-stage process for producing calcined petroleum coke having a sulfur content in the range of about 1.8 to about 2.5 wt. % and a vibrated bulk density of at least about 78 g/100 cc from raw petroleum coke produced by the delayed coking process having a sulfur content in the range of about 3.5 to about 5.0 wt. %, a volatile content in the range of about 9 to about 14 wt. %
and a particle size distribution of at least about 39 wt. %
greater than 3.36 mm which comprises:
(a) heating the coke at a temperature.in the range of about 250°C. to about 450°C. in an oxidizing atmosphere for a period in the range of about 1 hour to about 2 hours;
(b) heating the oxidized coke at a temperature in the range of about 600°C. to about 800°C. for a period of time of about 2 hours to about 6 hours in an atmosphere containing added hydrogen such that the sulfur content of said coke is reduced to a level in the range of about 2.8 to about 3.3 wt. %: and (c) heating the partially desulfurized coke at a temperature in the range of about 1350°C. to about 1600°C.
in the absence of added hydrogen for a period of time of about 0.5 hour to about 1.5 hours such that the sulfur content of the coke is reduced to a level of about 1.8 to about 2.5 wt. %.
and a particle size distribution of at least about 39 wt. %
greater than 3.36 mm which comprises:
(a) heating the coke at a temperature.in the range of about 250°C. to about 450°C. in an oxidizing atmosphere for a period in the range of about 1 hour to about 2 hours;
(b) heating the oxidized coke at a temperature in the range of about 600°C. to about 800°C. for a period of time of about 2 hours to about 6 hours in an atmosphere containing added hydrogen such that the sulfur content of said coke is reduced to a level in the range of about 2.8 to about 3.3 wt. %: and (c) heating the partially desulfurized coke at a temperature in the range of about 1350°C. to about 1600°C.
in the absence of added hydrogen for a period of time of about 0.5 hour to about 1.5 hours such that the sulfur content of the coke is reduced to a level of about 1.8 to about 2.5 wt. %.
9. The process of claims 6,7 or 8 wherein the oxidizing atmosphere consists of about 6 to about 14 wt.
oxygen.
oxygen.
10. The process of claims 6,7 or 8 wherein the final coke yield is no less than about 80 wt. % on a dried feed coke basis.
11. A three-stage process for producing calcined petroleum coke having a sulfur content in the range of about 1.5 to about 2.5 wt. % and a vibrated bulk density of at least about 78 g/100 cc from raw petroleum coke produced by the delayed coking process having a sulfur content greater than about 2.5 wt. %, a volatile content of at least about 7 wt. %, and a particle size distribution of at least about 19 wt. % greater than 6.73 mm which comprises:
a) heating the coke at a temperature in the range of about 250°C. to about 450°C. in an oxidizing atmosphere for a period no less than about 0.5 hour;
b) heating the oxidized coke at a temperature in the range of about 600°C. to about 800°C. in an atmosphere containing added hydrogen for a period of time sufficient to reduce the sulfur content of said coke to a level such that no more than about 1.5 wt. % of sulfur is required to he removed in the final stage; and c) heating the partially desulfurized coke at a temperature in the range of about 1350°C. to about 1600°C.
in the absence of added hydrogen for a period of time suffi-cient to reduce the sulfur content of the coke to within the range of about 1.5 to about 2.5 wt. %.
a) heating the coke at a temperature in the range of about 250°C. to about 450°C. in an oxidizing atmosphere for a period no less than about 0.5 hour;
b) heating the oxidized coke at a temperature in the range of about 600°C. to about 800°C. in an atmosphere containing added hydrogen for a period of time sufficient to reduce the sulfur content of said coke to a level such that no more than about 1.5 wt. % of sulfur is required to he removed in the final stage; and c) heating the partially desulfurized coke at a temperature in the range of about 1350°C. to about 1600°C.
in the absence of added hydrogen for a period of time suffi-cient to reduce the sulfur content of the coke to within the range of about 1.5 to about 2.5 wt. %.
12. A three-stage process for producing calcined petroleum coke having a sulfur content in the range of about 1.8 to about 2.5 st. % and a vibrated bulk density of at least about 78 g/100 cc from raw petroleum coke produced by the delayed coking process having a sulfur content in the range of about 3.5 to about 5.0 wt. %, a volatile content in the range of about 9 to about 14 wt. %
and a particle size distribution of at least about 19 wt. %
greater than 6.73 mm which comprises:
(a) heating the coke at a temperature in the range of about 250°C. to about 450°C. in an oxidizing atmosphere for a period in the range of about 1 hour to about 2 hours;
(b) heating the oxidized coke at a temperature in the range of about 600°C. to about 800°C. for a period of time of about 2 hours to about 6 hours in an atmosphere containing added hydrogen such that the sulfur content of said coke is reduced to a level in the range of about 2.8 to about 3.3 wt. %; and (c) heating the partially desulfurized coke at a temperature in the range of about 1350°C. to about 1600°C.
in the absence of added hydrogen for a period of time of about 0.5 hour to about 1.5 hours such that the sulfur content of the coke is reduced to a level of about 1.8 to about 2.5 wt. %.
and a particle size distribution of at least about 19 wt. %
greater than 6.73 mm which comprises:
(a) heating the coke at a temperature in the range of about 250°C. to about 450°C. in an oxidizing atmosphere for a period in the range of about 1 hour to about 2 hours;
(b) heating the oxidized coke at a temperature in the range of about 600°C. to about 800°C. for a period of time of about 2 hours to about 6 hours in an atmosphere containing added hydrogen such that the sulfur content of said coke is reduced to a level in the range of about 2.8 to about 3.3 wt. %; and (c) heating the partially desulfurized coke at a temperature in the range of about 1350°C. to about 1600°C.
in the absence of added hydrogen for a period of time of about 0.5 hour to about 1.5 hours such that the sulfur content of the coke is reduced to a level of about 1.8 to about 2.5 wt. %.
13. The process of claims 11 or 12 wherein the oxidizing atmosphere consists of about 6 to about 14 wt.
% oxygen.
% oxygen.
14. The process of claims 11 or 12 wherein the final coke yield is no less than about 80 wt.% on a dried feed coke basis.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US23382981A | 1981-02-12 | 1981-02-12 | |
| US233,829 | 1981-02-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1155414A true CA1155414A (en) | 1983-10-18 |
Family
ID=22878852
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000395619A Expired CA1155414A (en) | 1981-02-12 | 1982-02-05 | Process for calcining and desulfurizing petroleum coke |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS57151699A (en) |
| BR (1) | BR8200637A (en) |
| CA (1) | CA1155414A (en) |
| GB (1) | GB2093061B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4529717A (en) * | 1982-10-25 | 1985-07-16 | Atlantic Richfield Company | Partially calcined carbonaceous material as a reductant |
| GB2158088B (en) * | 1984-04-18 | 1988-12-29 | Exxon Research Engineering Co | Process and apparatus for the production of calcined coke |
| JPS6181491A (en) * | 1984-09-28 | 1986-04-25 | Kobe Steel Ltd | Desulfurization for carbon material |
| GB2312894A (en) * | 1996-05-10 | 1997-11-12 | Bailey Patricia | Aggregate for electrically conductive concrete |
| JP2015183143A (en) * | 2014-03-26 | 2015-10-22 | コスモ石油株式会社 | Low sulfur solid carbon body production process |
-
1982
- 1982-01-27 GB GB8202372A patent/GB2093061B/en not_active Expired
- 1982-02-05 BR BR8200637A patent/BR8200637A/en unknown
- 1982-02-05 CA CA000395619A patent/CA1155414A/en not_active Expired
- 1982-02-12 JP JP1986682A patent/JPS57151699A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| GB2093061A (en) | 1982-08-25 |
| BR8200637A (en) | 1982-12-14 |
| JPS57151699A (en) | 1982-09-18 |
| GB2093061B (en) | 1984-02-15 |
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