CA1283616C - Process of thermally cracking heavy petroleum oil - Google Patents
Process of thermally cracking heavy petroleum oilInfo
- Publication number
- CA1283616C CA1283616C CA000523656A CA523656A CA1283616C CA 1283616 C CA1283616 C CA 1283616C CA 000523656 A CA000523656 A CA 000523656A CA 523656 A CA523656 A CA 523656A CA 1283616 C CA1283616 C CA 1283616C
- Authority
- CA
- Canada
- Prior art keywords
- cracking
- tank reactor
- pitch
- heavy petroleum
- conversion
- 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 - Lifetime
Links
Landscapes
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
PROCESS OF THERMALLY CRACKING
HEAVY PETROLEUM OIL
Abstract A process of thermally cracking a heavy petroleum oil characterized in that the heavy petroleum oil is treated with the use of a combination of one cracking furnace and one perfect mixing type tank reactor, that the thermal cracking in the cracking furnace is performed at a temperature of 450-520 °C
with a conversion of at least 50 % of the total conversion rate and that the thermal cracking in the tank reactor is performed at a temperature of 400-450 °C to produce a liquid pitch having a volatile matter content of 30-45 wt % and useful as a fuel along with a gaseous product including cracked light oil.
HEAVY PETROLEUM OIL
Abstract A process of thermally cracking a heavy petroleum oil characterized in that the heavy petroleum oil is treated with the use of a combination of one cracking furnace and one perfect mixing type tank reactor, that the thermal cracking in the cracking furnace is performed at a temperature of 450-520 °C
with a conversion of at least 50 % of the total conversion rate and that the thermal cracking in the tank reactor is performed at a temperature of 400-450 °C to produce a liquid pitch having a volatile matter content of 30-45 wt % and useful as a fuel along with a gaseous product including cracked light oil.
Description
36,~
PROCESS OF THERMALLY CRACKING
HEAVY PETROLEUM OIL
Technical Field:
This invention relates to a process of continuously thermally cracking a heavy petroleum oil.
Prior Art:
Various methods are known for thermally cracking a heavy petroleum oil and for producing a liquid pitch and a cracked light oil. For example, United States patent No. 4,477,344 proposes a method of thermally cracking a heavy hydrocarbon oil with the use of one cracking furnace and two or more perfect mixing type reactors so as to obtain a pitch suitable as a fuel and a cracked light oil. This method is advantageous because the thermal cracking can be conducted in a continuous manner while effectively preventing the occurrence of coking troubles.
However, this method is not fully satisfactory from the standpoint of economy and apparatus efficiency because the method requires the use of two or more perfect mixing type reactors operated at temperatures which are gradually increased in the later stages.
United States patent No. 4,581,124 discloses a method in which a heavy feed stock is thermally cracked with the use of a combination of one cracking furnace and one tank reactor. In this method, since the conversion rate in the cracking furnace is suppressed to a low degree and the thermal cracking is mainly effected in the tank reactor, coking troubles are apt to occur in the tank reactor. To prevent the occurrence of coking troubles in the tank reactor, a mixture of mesophase pitch and matrix pitch (isotropic pitch) is continuously withdrawn from the tank reactor and is introduced into a separator for the sepration of the mixture into the mesophase pitch and the matrix ~ ~ Z~336~
~ - 2 -pitch. The mesophase pitch thus separated is recovered while the matrix pitch thus separated is recycled to the tank reactor to keep the ratio of the matrix pitch to the mesophase pitch within the rank reactor high. Thus, the prior art method has a drawback because the operation in the separating step becomes complicated due to the necessity for keeping the ratio of the matrix pitch to the mesophase pitch high.
Obiect:
It is an object of an aspect of the present invention to provide a process of thermally cracking a heavy petroleum oil which is devoid of the drawbacks of the conventional technique and which is free of coking troubles.
An object of an aspect of the present invention is to provide a process of thermally cracking a heavy petroleum oil with the utilization of a combination of one thermal cracking furnace and one tank reactor while preventing the occurrence of coking troubles in the tank reactor.
Constitution:
An aspect of this invention is as follows:
A process of thermally cracking a heavy petroleum oil characterized in that the heavy petroleum oil is treated with the use of a combination of one cracking furnace and one perfect mixing type tank reactor, that the thermal cracking in the cracking furnace is performed at a temperature of 450-520C and a pressure of from ambient pressure to 20 kg/cm2 with a conversion of 50-80% of the total conversion rate and that the thermal cracking in the tank reactor is performed at a temperature of 400-450C and a pressure of 100 mmHg to 5 kg/cm2 for 10-120 minutes with a conversion of not higher than 50% of the total conversion rate while r~
~ . - ~
12836~6 - 2a -feeding steam in such an amount as to maintain the partial pressure of hydrocarbons in the range of 100-600 mmHg to produce a liquid pitch having a volatile matter content of 30-45 wt % and useful as a fuel along with a gaseous product including cracked light oil.
The present invention will be described in detail below with reference to the accompanying drawing, in which the sole FIGURE illustrates a flow diagram for carrying out the process according to the present invention.
Examples of the heavy petroleum oils used in the present lZ1~36~L6 invention include atmospheric and vacuum residues of petroleum crude oils, various cracking residues, asphalt products from solvent deasphalting and native natural asphalt.
When such a heavy hydrocarbon oil is subjected to a thermal cracking treatment in a known manner with the use of a combination of one cracking furnace and one tank reactor, mesophase is formed in a large amount. The mesophase tends to coalesce with each other to grow to large particles. Namely, carbon is apt to form so that coking troubles are liable to occur. Upon study by the present inventors, it has been found that such coking troubles in the tank reactor can be effectively prevented from occurring by increasing the conversion in the cracking furnace. When the thermal cracking product obtained in the cracking furnace with a high conversion rate is treated in the succeeding tank reactor, the mesophase produced in the tank reactor is small in size and excellent in dispersibility.
Therefore, precipitation of carbon (coking) hardly occurs and, hence, coking troubles in the tank reactor are prevented.
The process of the present invention is conducted with the use of a combination of one cracking furnace and one perfect mixing type tank reactor. In this process, the feed stock is thermally cracked in the cracking furnace until at least 50 % of the total thermal cracking conversion is reachedO
The term "total thermal cracking conversion" used in the present specification is intended to mean the total conversion accomplished in the cracking furnace and the tank reactor and is defined by the following equation:
R = [(A - C)/A]x100 (I) = ~(A - B)/A + (B - C)/A] x 100 (II) 30 wherein R: Total thermal cracking conversion (~) A: The weight of the components in the feed stock which have a boiling point of at least C: The weight of the components contained in the thermal cracking product which are _ 4 _ ~2~36~6 obtained in the tank reactor and which ha~e a boiling point of at least 538 C
B: The weight of the components contained in the thermal cracking product which are obtained in the cracking furnace and which have a boiling point of at least 538 C
[~A - s)/~]x100: Conversion (%) in the cracking furnace ~(B - C~/A]x100: Conversion (%~ in the tank reactor The total thermal cracking conversion is selected according to the kind of the feed stock and the like. Generaly speaking, the total conversion required for obtaining pitch having volatile matter content of 30-45 wt % is 65-75 %.
The reaction conditions adopted in the cracking furnace include a temperature of 450-520 C and a pressure of from ambient pressure to 20 kg/cm2~ In the cracking furnace, the thermal cracking is conducted so that the conversion in this step is at least 50 - 80 %, preferably 60-75 % of the total thermal cracking conversion. The conversion in the cracking furnace may be controlled by the control of the reaction temperature, reaction pressure and residence time.
The reaction conditions in the perfect mixing type tank reactor involve a reaction temperature of 400-450 C, a reaction pressure of 100 mmHg to 5 Kg/cm2 and a reaction time of 10-120 min, preferably 20-60 min. The perfect mixing type tank reactor is operated under a reduced pressure or under a partial pressure of hydrocarbons of 100-600 mmHg by feeding an inert gas such as steam. The thermal cracking in the perfect mixing type tank reactor is conducted so that the conversion does not exceed 50 %, preferably falls within the range of 25-40 % of the total thermal cracking conversion. The conversion can be controlled by controlling the reaction temperature, partial pressure of hydrocarbon and reaction time. When the reaction temperature and pressure are kept constant, the conversion can be controlled by control of the reaction time. In the perfect mixing type tank reactor, liquid pitch and gaseous product including cracked light oil are produced. The liquid pitch thus produced contain ; :
- 5 - ~2~3G~6 mesophase. The amount of the mesophase is relatively small, i.e.
generally 30 vol % or less, especially 15-25 vol ~. The mesophase has a particle size of 20-50~m and is excellent in dispersibility in the pitch. ~he mesophase is hardly carbonized (formation of coke).
The cracking furnace may be, for example, an external heating type tubular reactor while the tank reactor may be, for example, of a type equipped with an agitating apparatus within the reactor. If desired, the tank reactor can be further provided with a wet wall system or a scraper to keep the inside wall of the reactor clean. Any known cracking furnace and the tank reactor may be suitably used for the purpose of the present inventionO
In the process according to the present invention, a cracked heavy oil produced in the process may be recycled to the cracking furnace to increase the overall yield of cracked light oil. The cracked heavy hydrocarbon oil suitably used for this purpose has generally a boling point of 340 C or more. The amount of the cracked oil recycled is 0.1-0.3 part by weight per one part by weight of the feed stock. Too large an amount of the recycled heavy cracked oil causes the increase of the cracked gas and pitch and reduction of total liquid yield.
Referring now to the FIGURE, the feed stock is fed to a cracking furnace 1 through a line 5. In this case, before being introduced into the cracking furnace 1, the feed stock may be mixed with a cracked heavy oil recycled through a line 17 from the bottom of a ~ractionating tower 4, if desired. The feed stock which is mixed with the cracked heavy oil is subjected to a thermal cracking treatment in the cracking furnace 1 and the resulting cracked product is fed through a line 7 to a perfect mixing type tank reactor 2 where it is subjected to a further thermal cracking treatment. To the bottom of the tank reactor 2 is supplied through a line 8 high temperature steam ~with a temperature of about 400-700 C) which has been fed through a line 6 and heated in the cracking furnace 1 and, if necessary, by means of a steam super heater 12. The steam serves to heat a ~Z83~1~
liquid pitch contained in the reactor 2 for the further thermal cracking thereof, to accelerate the stripping of volatile components from the liquid pitch and to decrease the partial pressure of hydrocarbons in the space within the reactor 2. The steam supplied to the reactor 2 is not necessarily high temperature steam heated by means of a steam super heater 12.
When steam which is not heated by means of the super heater is supplied to the reactor 2, the steam serves to strip volatile components from the liquid pitch and to decrease the partial pressure of hydrocarbons in the space within the reactor 2.
The gas components including the cracked oil produced in the reactor 2 are introduced into a fractionating tower 4 through a line 10, whereas the liquid pitch obtained in the reactor 2 is discharged threfrom through a line 9 and introduced into a pitch cooling drum 3 where the liquid pitch is cooled for the termination of the reaction. The liquid pitch in the cooling drum 3 is discharged therefrom through a line 11 and recovered as a pitch product. The pitch product has a volatile matter content of 30-45 wt % and a softening point of 160-220 C
and is suitable for use as a fuel pitch.
The gas components introduced into the fractionating tower 4 through the line 10 are fractionated into a cracked gas discharged through a line 14, a cracked light oil (boling point of C5-370 C) discharged through a line 15, a cracked heavy oil 25 (boling point of 370-538 C) discharged through a line 16 and a recycling cracked heavy oil (boiling point of 535 ~C or more) discharged through a line 17. The cracked heavy oil discharged through the line 17 is recycled for mixing with the feed stock to be fed to the cracking furnace 1.
The process shown in the FIGURE can be varied and modified in various manners. For example, the fractionating tower 4 may be composed of a combination of two or more fractionating towers. Further, in stead of directly feeding the feed stock to the cracking furnace, the feed stock can be previously introduced into the fractionating tower 4, introducing the mixture of the feed stock and the cracked heavy oil obtained in _ 7 _ '12~361~
the bottom of the fractionating tower 4 into the cracking furnace 1. Furthermore, the cracked heavy oil discharged through the line 16 may be added to the cracked heavy oil discharged from the bottom of the tower 4 for mixing with the feed stock. The recycling of the cracked heavy oil for mixing with the feed stock is not essential but can be omitted.
The above-described process according to the present invention uses a combination of one cracking furnace and one perfect mixing type tank reactor for the thermal cracking treatment of petroleum heavy hydrocarbon oil and permits one to continuously obtain a sufficiently lightened, cracked oil and a pitch which is suitable as a fuel and which contains a volatile matter in the amount of 30-45 wt ~, without encountering coking troubles in the tank reactor. In the conventional thermal cracking treatment of heavy petroleum hydrocarbon oils using a combination of one cracking furnace and one perfect mixing type tank reactor, the mesophase produced in the tank reactor tends to coalesce to form precipitates of carbon, namely tends to encounter coking troubles. In contrast, the mesophase in the pitch produced according to the process of the present invention, in which the thermal cracking conversion rate in the cracking furnace is made high, has a small particle size, hardly coalesces, and is excellent in dispersibility in the pitch, so that precipitation of carbon scarecely occurs.
In addition to the above-described merits, the present invention has the following advantages:
(1) Since majority of the reaction hea~ may be supplied from the cracking furnace, the amount of the heating gas medium can be reduced so that the operation cost can be considerably reduced.
PROCESS OF THERMALLY CRACKING
HEAVY PETROLEUM OIL
Technical Field:
This invention relates to a process of continuously thermally cracking a heavy petroleum oil.
Prior Art:
Various methods are known for thermally cracking a heavy petroleum oil and for producing a liquid pitch and a cracked light oil. For example, United States patent No. 4,477,344 proposes a method of thermally cracking a heavy hydrocarbon oil with the use of one cracking furnace and two or more perfect mixing type reactors so as to obtain a pitch suitable as a fuel and a cracked light oil. This method is advantageous because the thermal cracking can be conducted in a continuous manner while effectively preventing the occurrence of coking troubles.
However, this method is not fully satisfactory from the standpoint of economy and apparatus efficiency because the method requires the use of two or more perfect mixing type reactors operated at temperatures which are gradually increased in the later stages.
United States patent No. 4,581,124 discloses a method in which a heavy feed stock is thermally cracked with the use of a combination of one cracking furnace and one tank reactor. In this method, since the conversion rate in the cracking furnace is suppressed to a low degree and the thermal cracking is mainly effected in the tank reactor, coking troubles are apt to occur in the tank reactor. To prevent the occurrence of coking troubles in the tank reactor, a mixture of mesophase pitch and matrix pitch (isotropic pitch) is continuously withdrawn from the tank reactor and is introduced into a separator for the sepration of the mixture into the mesophase pitch and the matrix ~ ~ Z~336~
~ - 2 -pitch. The mesophase pitch thus separated is recovered while the matrix pitch thus separated is recycled to the tank reactor to keep the ratio of the matrix pitch to the mesophase pitch within the rank reactor high. Thus, the prior art method has a drawback because the operation in the separating step becomes complicated due to the necessity for keeping the ratio of the matrix pitch to the mesophase pitch high.
Obiect:
It is an object of an aspect of the present invention to provide a process of thermally cracking a heavy petroleum oil which is devoid of the drawbacks of the conventional technique and which is free of coking troubles.
An object of an aspect of the present invention is to provide a process of thermally cracking a heavy petroleum oil with the utilization of a combination of one thermal cracking furnace and one tank reactor while preventing the occurrence of coking troubles in the tank reactor.
Constitution:
An aspect of this invention is as follows:
A process of thermally cracking a heavy petroleum oil characterized in that the heavy petroleum oil is treated with the use of a combination of one cracking furnace and one perfect mixing type tank reactor, that the thermal cracking in the cracking furnace is performed at a temperature of 450-520C and a pressure of from ambient pressure to 20 kg/cm2 with a conversion of 50-80% of the total conversion rate and that the thermal cracking in the tank reactor is performed at a temperature of 400-450C and a pressure of 100 mmHg to 5 kg/cm2 for 10-120 minutes with a conversion of not higher than 50% of the total conversion rate while r~
~ . - ~
12836~6 - 2a -feeding steam in such an amount as to maintain the partial pressure of hydrocarbons in the range of 100-600 mmHg to produce a liquid pitch having a volatile matter content of 30-45 wt % and useful as a fuel along with a gaseous product including cracked light oil.
The present invention will be described in detail below with reference to the accompanying drawing, in which the sole FIGURE illustrates a flow diagram for carrying out the process according to the present invention.
Examples of the heavy petroleum oils used in the present lZ1~36~L6 invention include atmospheric and vacuum residues of petroleum crude oils, various cracking residues, asphalt products from solvent deasphalting and native natural asphalt.
When such a heavy hydrocarbon oil is subjected to a thermal cracking treatment in a known manner with the use of a combination of one cracking furnace and one tank reactor, mesophase is formed in a large amount. The mesophase tends to coalesce with each other to grow to large particles. Namely, carbon is apt to form so that coking troubles are liable to occur. Upon study by the present inventors, it has been found that such coking troubles in the tank reactor can be effectively prevented from occurring by increasing the conversion in the cracking furnace. When the thermal cracking product obtained in the cracking furnace with a high conversion rate is treated in the succeeding tank reactor, the mesophase produced in the tank reactor is small in size and excellent in dispersibility.
Therefore, precipitation of carbon (coking) hardly occurs and, hence, coking troubles in the tank reactor are prevented.
The process of the present invention is conducted with the use of a combination of one cracking furnace and one perfect mixing type tank reactor. In this process, the feed stock is thermally cracked in the cracking furnace until at least 50 % of the total thermal cracking conversion is reachedO
The term "total thermal cracking conversion" used in the present specification is intended to mean the total conversion accomplished in the cracking furnace and the tank reactor and is defined by the following equation:
R = [(A - C)/A]x100 (I) = ~(A - B)/A + (B - C)/A] x 100 (II) 30 wherein R: Total thermal cracking conversion (~) A: The weight of the components in the feed stock which have a boiling point of at least C: The weight of the components contained in the thermal cracking product which are _ 4 _ ~2~36~6 obtained in the tank reactor and which ha~e a boiling point of at least 538 C
B: The weight of the components contained in the thermal cracking product which are obtained in the cracking furnace and which have a boiling point of at least 538 C
[~A - s)/~]x100: Conversion (%) in the cracking furnace ~(B - C~/A]x100: Conversion (%~ in the tank reactor The total thermal cracking conversion is selected according to the kind of the feed stock and the like. Generaly speaking, the total conversion required for obtaining pitch having volatile matter content of 30-45 wt % is 65-75 %.
The reaction conditions adopted in the cracking furnace include a temperature of 450-520 C and a pressure of from ambient pressure to 20 kg/cm2~ In the cracking furnace, the thermal cracking is conducted so that the conversion in this step is at least 50 - 80 %, preferably 60-75 % of the total thermal cracking conversion. The conversion in the cracking furnace may be controlled by the control of the reaction temperature, reaction pressure and residence time.
The reaction conditions in the perfect mixing type tank reactor involve a reaction temperature of 400-450 C, a reaction pressure of 100 mmHg to 5 Kg/cm2 and a reaction time of 10-120 min, preferably 20-60 min. The perfect mixing type tank reactor is operated under a reduced pressure or under a partial pressure of hydrocarbons of 100-600 mmHg by feeding an inert gas such as steam. The thermal cracking in the perfect mixing type tank reactor is conducted so that the conversion does not exceed 50 %, preferably falls within the range of 25-40 % of the total thermal cracking conversion. The conversion can be controlled by controlling the reaction temperature, partial pressure of hydrocarbon and reaction time. When the reaction temperature and pressure are kept constant, the conversion can be controlled by control of the reaction time. In the perfect mixing type tank reactor, liquid pitch and gaseous product including cracked light oil are produced. The liquid pitch thus produced contain ; :
- 5 - ~2~3G~6 mesophase. The amount of the mesophase is relatively small, i.e.
generally 30 vol % or less, especially 15-25 vol ~. The mesophase has a particle size of 20-50~m and is excellent in dispersibility in the pitch. ~he mesophase is hardly carbonized (formation of coke).
The cracking furnace may be, for example, an external heating type tubular reactor while the tank reactor may be, for example, of a type equipped with an agitating apparatus within the reactor. If desired, the tank reactor can be further provided with a wet wall system or a scraper to keep the inside wall of the reactor clean. Any known cracking furnace and the tank reactor may be suitably used for the purpose of the present inventionO
In the process according to the present invention, a cracked heavy oil produced in the process may be recycled to the cracking furnace to increase the overall yield of cracked light oil. The cracked heavy hydrocarbon oil suitably used for this purpose has generally a boling point of 340 C or more. The amount of the cracked oil recycled is 0.1-0.3 part by weight per one part by weight of the feed stock. Too large an amount of the recycled heavy cracked oil causes the increase of the cracked gas and pitch and reduction of total liquid yield.
Referring now to the FIGURE, the feed stock is fed to a cracking furnace 1 through a line 5. In this case, before being introduced into the cracking furnace 1, the feed stock may be mixed with a cracked heavy oil recycled through a line 17 from the bottom of a ~ractionating tower 4, if desired. The feed stock which is mixed with the cracked heavy oil is subjected to a thermal cracking treatment in the cracking furnace 1 and the resulting cracked product is fed through a line 7 to a perfect mixing type tank reactor 2 where it is subjected to a further thermal cracking treatment. To the bottom of the tank reactor 2 is supplied through a line 8 high temperature steam ~with a temperature of about 400-700 C) which has been fed through a line 6 and heated in the cracking furnace 1 and, if necessary, by means of a steam super heater 12. The steam serves to heat a ~Z83~1~
liquid pitch contained in the reactor 2 for the further thermal cracking thereof, to accelerate the stripping of volatile components from the liquid pitch and to decrease the partial pressure of hydrocarbons in the space within the reactor 2. The steam supplied to the reactor 2 is not necessarily high temperature steam heated by means of a steam super heater 12.
When steam which is not heated by means of the super heater is supplied to the reactor 2, the steam serves to strip volatile components from the liquid pitch and to decrease the partial pressure of hydrocarbons in the space within the reactor 2.
The gas components including the cracked oil produced in the reactor 2 are introduced into a fractionating tower 4 through a line 10, whereas the liquid pitch obtained in the reactor 2 is discharged threfrom through a line 9 and introduced into a pitch cooling drum 3 where the liquid pitch is cooled for the termination of the reaction. The liquid pitch in the cooling drum 3 is discharged therefrom through a line 11 and recovered as a pitch product. The pitch product has a volatile matter content of 30-45 wt % and a softening point of 160-220 C
and is suitable for use as a fuel pitch.
The gas components introduced into the fractionating tower 4 through the line 10 are fractionated into a cracked gas discharged through a line 14, a cracked light oil (boling point of C5-370 C) discharged through a line 15, a cracked heavy oil 25 (boling point of 370-538 C) discharged through a line 16 and a recycling cracked heavy oil (boiling point of 535 ~C or more) discharged through a line 17. The cracked heavy oil discharged through the line 17 is recycled for mixing with the feed stock to be fed to the cracking furnace 1.
The process shown in the FIGURE can be varied and modified in various manners. For example, the fractionating tower 4 may be composed of a combination of two or more fractionating towers. Further, in stead of directly feeding the feed stock to the cracking furnace, the feed stock can be previously introduced into the fractionating tower 4, introducing the mixture of the feed stock and the cracked heavy oil obtained in _ 7 _ '12~361~
the bottom of the fractionating tower 4 into the cracking furnace 1. Furthermore, the cracked heavy oil discharged through the line 16 may be added to the cracked heavy oil discharged from the bottom of the tower 4 for mixing with the feed stock. The recycling of the cracked heavy oil for mixing with the feed stock is not essential but can be omitted.
The above-described process according to the present invention uses a combination of one cracking furnace and one perfect mixing type tank reactor for the thermal cracking treatment of petroleum heavy hydrocarbon oil and permits one to continuously obtain a sufficiently lightened, cracked oil and a pitch which is suitable as a fuel and which contains a volatile matter in the amount of 30-45 wt ~, without encountering coking troubles in the tank reactor. In the conventional thermal cracking treatment of heavy petroleum hydrocarbon oils using a combination of one cracking furnace and one perfect mixing type tank reactor, the mesophase produced in the tank reactor tends to coalesce to form precipitates of carbon, namely tends to encounter coking troubles. In contrast, the mesophase in the pitch produced according to the process of the present invention, in which the thermal cracking conversion rate in the cracking furnace is made high, has a small particle size, hardly coalesces, and is excellent in dispersibility in the pitch, so that precipitation of carbon scarecely occurs.
In addition to the above-described merits, the present invention has the following advantages:
(1) Since majority of the reaction hea~ may be supplied from the cracking furnace, the amount of the heating gas medium can be reduced so that the operation cost can be considerably reduced.
(2) Since the feed to be subjected to the thermal cracking treatment in the tank reactor is a product obtained by thermal cracking of a feed stock at a high conversion rate in a cracking furnace in which the reaction time is not distributed, it is possible to reduce the reaction load in the tank reactor.
Therefore, the tank reactor can be constructed into a small - 8 ~ ~ ~36~6 sized reactor. Moreover, the pitch obtained in the tank reactor has uniform properties and is low in content of highly polycondensed components such as mesophase and quinoline insolubles. Such a pitch when used as binder for the preparation of metallugical coke exibits excellent properties as a binder and when used as a fuel is excellent in perfect combustibility.
The present invention will described in more detail by way of examples.
Example 1 Using the apparatus as shown in the FIGURE, a heavy petroleum oil having the properties shown in Table 1 was treated for thermal cracking. Thus, the feed stock was fed to a cracking furnace at a feed rate of 300kg/hr where it was thermally cracked and the resulting-thermally cracked product was introduced into a perfect mixing type reactor ~stirring tank reactor with an inside diameter of 500 mm and a height of 3000 mm) to which steam was supplied from the bottom for further thermal cracking. The conversion rates in the cracking furnace and the tank reactor were varied by varying the reaction time, with the total conversion being kept constant (about 67 %). The pitch products obtained were examined for their coking -tendency in the perfect mixing type reactor, the results of which are summarized in Table 2.
g ~LZ~33~1~
Table 1 Properties of Feed Stock Specific gravity (15/4 C) 1.021 Molecular weight 934 Heptane insolubles (wt%) 8.93 Conradson carbon residue (wt%) 20.8 Elementary analysis (wt %) Carbon 84.56 Hydrogen 10.37 Sulfur 3.95 Nitrogen 0.51 Table 2 Properties of Pitch _ _ _ Experiment Conversion (%) ¦ Properties of Pitch ~ _ No. Crac]cing Tank ¦ Particle size Coking Furnace Reactor I of Mesophase ~ m) Tendency 1 ___ _ 70 r 100< _ great 2 45 55 50-100 fair 3 60 40 30-50 none 4 _ 75 _5_ _ 20 30 _ _ none The coking tendency was determined as follows:
Mesophase in the pitch was observed by polarizing microscope to evaluate the coking tendency by the particle size of the mesophase unit and the degree of coalescence. Evaluation was made according to the following ratings.
None: No coking Fair: Coking occurred slightly Great: Coking occurred considerably
Therefore, the tank reactor can be constructed into a small - 8 ~ ~ ~36~6 sized reactor. Moreover, the pitch obtained in the tank reactor has uniform properties and is low in content of highly polycondensed components such as mesophase and quinoline insolubles. Such a pitch when used as binder for the preparation of metallugical coke exibits excellent properties as a binder and when used as a fuel is excellent in perfect combustibility.
The present invention will described in more detail by way of examples.
Example 1 Using the apparatus as shown in the FIGURE, a heavy petroleum oil having the properties shown in Table 1 was treated for thermal cracking. Thus, the feed stock was fed to a cracking furnace at a feed rate of 300kg/hr where it was thermally cracked and the resulting-thermally cracked product was introduced into a perfect mixing type reactor ~stirring tank reactor with an inside diameter of 500 mm and a height of 3000 mm) to which steam was supplied from the bottom for further thermal cracking. The conversion rates in the cracking furnace and the tank reactor were varied by varying the reaction time, with the total conversion being kept constant (about 67 %). The pitch products obtained were examined for their coking -tendency in the perfect mixing type reactor, the results of which are summarized in Table 2.
g ~LZ~33~1~
Table 1 Properties of Feed Stock Specific gravity (15/4 C) 1.021 Molecular weight 934 Heptane insolubles (wt%) 8.93 Conradson carbon residue (wt%) 20.8 Elementary analysis (wt %) Carbon 84.56 Hydrogen 10.37 Sulfur 3.95 Nitrogen 0.51 Table 2 Properties of Pitch _ _ _ Experiment Conversion (%) ¦ Properties of Pitch ~ _ No. Crac]cing Tank ¦ Particle size Coking Furnace Reactor I of Mesophase ~ m) Tendency 1 ___ _ 70 r 100< _ great 2 45 55 50-100 fair 3 60 40 30-50 none 4 _ 75 _5_ _ 20 30 _ _ none The coking tendency was determined as follows:
Mesophase in the pitch was observed by polarizing microscope to evaluate the coking tendency by the particle size of the mesophase unit and the degree of coalescence. Evaluation was made according to the following ratings.
None: No coking Fair: Coking occurred slightly Great: Coking occurred considerably
Claims
1. A process of thermally cracking a heavy petroleum oil characterized in that the heavy petroleum oil is treated with the use of a combination of one cracking furnace and one perfect mixing type tank reactor, that the thermal cracking in the cracking furnace is performed at a temperature of 450-520°C and a pressure of from ambient pressure to 20 kg/cm2 with a conversion of 50-80% of the total conversion rate and that the thermal cracking in the tank reactor is performed at a temperature of 400-450°C and a pressure of 100 mmHg to 5 kg/cm2 for 10-120 minutes with a conversion of not higher than 50% of the total conversion rate while feeding steam in such an amount as to maintain the partial pressure of hydrocarbons in the range of 100-600 mmHg to produce a liquid pitch having a volatile matter content of 30-45 wt % and useful as a fuel along with a gaseous product including cracked light oil.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60-264,119 | 1985-11-25 | ||
| JP26411985A JPH0689343B2 (en) | 1985-11-25 | 1985-11-25 | Pyrolysis treatment method for heavy petroleum oil |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1283616C true CA1283616C (en) | 1991-04-30 |
Family
ID=17398750
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000523656A Expired - Lifetime CA1283616C (en) | 1985-11-25 | 1986-11-24 | Process of thermally cracking heavy petroleum oil |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPH0689343B2 (en) |
| CA (1) | CA1283616C (en) |
-
1985
- 1985-11-25 JP JP26411985A patent/JPH0689343B2/en not_active Expired - Fee Related
-
1986
- 1986-11-24 CA CA000523656A patent/CA1283616C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0689343B2 (en) | 1994-11-09 |
| JPS62124191A (en) | 1987-06-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5580443A (en) | Process for cracking low-quality feed stock and system used for said process | |
| US3966585A (en) | Manufacture of coke from a coal extract | |
| US3956101A (en) | Production of cokes | |
| EP0044761A2 (en) | Process of preparation of a mesophase pitch for producing carbon fibers | |
| CA1110193A (en) | Method of thermally cracking heavy petroleum oil | |
| US4581124A (en) | Process for thermally cracking heavy hydrocarbon oil | |
| CN113667505B (en) | Production method and production system of mesophase pitch | |
| CN86102643B (en) | Process for treating heavy petroleum oil reside | |
| US4663022A (en) | Process for the production of carbonaceous pitch | |
| US4836909A (en) | Process of thermally cracking heavy petroleum oil | |
| CA1202589A (en) | Process of thermally cracking heavy hydrocarbon oils | |
| JPS6158514B2 (en) | ||
| RU2062285C1 (en) | Method to produce petroleum fiber-forming pitch | |
| EP0285261B1 (en) | Premium coking process | |
| CA1283616C (en) | Process of thermally cracking heavy petroleum oil | |
| US4859284A (en) | Combined process for the separation and continuous coking of high softening point asphaltenes | |
| US4624807A (en) | Process for producing microspherical, oil-containing carbonaceous particles | |
| US4961837A (en) | Process for the production of petroleum tar pitch for use as a binder in the production of electrodes | |
| CN113667506B (en) | Preparation method and preparation system of mesophase pitch | |
| CA1288716C (en) | Process of thermally cracking heavy petroleum oil | |
| EP0455504B1 (en) | Coking decanted oil and other heavy oils to produce a superior quality of needle-grade coke | |
| GB2083492A (en) | Production of pitch from petroleum fractions | |
| US4220474A (en) | Amorphous refractory compositions | |
| US5228981A (en) | Coal as an additive to accelerate thermal cracking in coking | |
| GB2103650A (en) | Microspherical pitch spheres |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |