CA1107672A - Process for thermally cracking heavy petroleum oil - Google Patents
Process for thermally cracking heavy petroleum oilInfo
- Publication number
- CA1107672A CA1107672A CA307,370A CA307370A CA1107672A CA 1107672 A CA1107672 A CA 1107672A CA 307370 A CA307370 A CA 307370A CA 1107672 A CA1107672 A CA 1107672A
- Authority
- CA
- Canada
- Prior art keywords
- oil
- vessel
- heavy petroleum
- petroleum oil
- heavy
- 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
Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G9/00—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
- C10G9/34—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils by direct contact with inert preheated fluids, e.g. with molten metals or salts
- C10G9/36—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils by direct contact with inert preheated fluids, e.g. with molten metals or salts with heated gases or vapours
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D19/00—Degasification of liquids
- B01D19/02—Foam dispersion or prevention
- B01D19/04—Foam dispersion or prevention by addition of chemical substances
- B01D19/0404—Foam dispersion or prevention by addition of chemical substances characterised by the nature of the chemical substance
- B01D19/0409—Foam dispersion or prevention by addition of chemical substances characterised by the nature of the chemical substance compounds containing Si-atoms
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/0006—Controlling or regulating processes
- B01J19/002—Avoiding undesirable reactions or side-effects, e.g. avoiding explosions, or improving the yield by suppressing side-reactions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/00049—Controlling or regulating processes
- B01J2219/00245—Avoiding undesirable reactions or side-effects
- B01J2219/0025—Foam formation
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Engineering & Computer Science (AREA)
- General Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Dispersion Chemistry (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE:
Herein disclosed is a process for thermally cracking a heavy petroleum oil, which includes introducing a preheated heavy petroleum oil into a reaction vessel in which the oil is contacted with a superheated steam to effect the thermal cracking. In the process, a predetermined amount of a silicone antifoamer is added to the heavy petroleum oil prior to the introduction into the vessel.
Herein disclosed is a process for thermally cracking a heavy petroleum oil, which includes introducing a preheated heavy petroleum oil into a reaction vessel in which the oil is contacted with a superheated steam to effect the thermal cracking. In the process, a predetermined amount of a silicone antifoamer is added to the heavy petroleum oil prior to the introduction into the vessel.
Description
1~76'72 Il FIELD OF THE INVENTION: i This invention relates to a process for thermally Il cracking a heavy petroleum oil in a reaction vessel and more l¦ particularly, to an improvement in effectively preventing the ¦l foaming of the heavy oil upon the thermal cracking.
B~CKGROUN~ OF THE INVENTION:
A num~er of processes of thermally cracking a heavy i¦ petroleum oil are known including a process in which the ¦ heavy petroleum otl heated to 45~-550C is continuously ¦j charged into a reaction vessel for contact with a superheated I ¦ steam of 500-800~C therein, to undergo the thermal cracking to obtain a cracked gas / a cracked oil and a petroleum pitch.
In this process, however~ foams caused by evaporation of the thermally cracked oils and the employed steam tend to I accumulate in the bottom oil (composed of the raw material ¦ and cracked product, l.e. a mixture of the unreacted heavy petroleum o;~l and pitch~. As a result, there appears a l¦ phenomenon that the oil rises in foams in the reaction I li vessel. The foamtng of the bottom oil will undesirably involve I discharge of the kottom oil in large amount~ together with ¦I cracked gases, from an exhaust port located at the upper i section of the vessel. The bottom oil which is susceptible ¦ to coke is deposited in greatly increased amount on the ¦l inner wall o~ a gas discharge pipe connected to the discharge I port and also on the inner wall of the reaction vessel in a Il ~ 2 ~ `
IL~LQ76~
zone of gas phase at the upper section of the vessel. If a large amount of coke is formed and deposited on the inner wall of the vessel, the reaction vessel is reduced in its l effective capacity. This necessitates the use of a sufficiently 1 large-sized reaction vessel, inviting a great imposition from j a viewpoint of economy. Further, the deposition of coke on the inner wall of the reaction vessel will facilitate expansion of the heavy oil by the foaming, thus greatly increase the amount of deposltion of the formed coke. The coke deposited lQin a large amount often falls off from the inner wall in a form of lumps and is dropped into the heavy oil. This will frequently impede the withdrawal of the reaction residue (petro-leum pitch~ from the reaction vessel after completion of the reaction, and the petroleum pitch obtained becomes reduced I in quality due to contamination with such coke. On the other hand, if the coke is deposited on the inner wall of the exhaust ¦I pipe in a large amount, the discharge of gases is rendered ¦¦ difficult accompanying with an increased internal pressure I I of the reaction vessel, making the safe and continuous operation 20 ¦I Yery difficult.
¦¦ In order to overcome these disadvantages, there have ¦¦ been proposed a number of methods of preventing the foaming ¦¦ of the heavy oil upon the thermal cracking of the oil in a I I reaction vessel. For example, in a thermal cracking process ~5of heavy petroleur oll using a un~t such as delayed coker, I
11~7672 etc. a silicone-oased antiFoamer is sprayed into the vessel ¦¦ from the top thereof for a predetermined time after the Il ~oaming oE the heavy oil. However, the antifoaming treatment ¦¦ of the a~ove type can not o~tain a satisfactory effect when 5 ¦¦ applied to the thermal cracking process wherein a large amount of superheated steam is blown into the heavy petroleum ¦ oil for producing a Petroleum pitch, a cracked oil and a cracked gas.
SUMMARY 0~ THE INVENTION:
_. ... _ It is therefore an object of the present invention to proyide a process of the thermal cracking of a heavy petro-leum oil with a superheated steam, ~y which the foaming of the heavy oil occurring upon the thermal cracking can be very ¦ effectively prevented.
¦ Thls and other objects of the present invention will become apparent from the follo~ing detailed description.
In order to achieve the above object, we have made an extensive study on the cracking process and, as a result~
l found that when a heavy petroleum oil to which a predetermined ¦ amount o~ a silicone-based antifoamer has been added in advance is subjected to the thermal cracking by the afore-described prior technique-, the foaming of ~he heavy oil in the reaction ¦ vessel can be effectivel~ prevented. The process of the pre-¦¦ sent invention is based on this finding.
Accordin~ to the present invention, there is provided 11276~
a process for thermally cracking a heavy petroleum oil comprising heating the heavy petroleum oil to a temperature of 450-550C, adding a silicone-based antifoamer at 5 - 20ppm by weight to the heated oilS introducing the heated oil into a reaction ¦ vessel and contacting the oil with superheated steam of a temperature of 500 - 800C to effect the thermal cracking.
I BRIEF DESCRIPTION OF THE DRAWING^
.
The accompanying drawing is a flow chart showing one embodiment for carrying out the process for thermally cracking a heavy petroleum oil according to the invention.
: DETAILED DESCRIPTI3N OF THE INVENTION:
The heavy petroleum oil to be treated according to the process of the invention is not restrictive and includes, for example, a topped crude, a vacuum residue, a thermally cracked residue and other various petroleu~ residue oils. In practice, the heavy petroleum oil 1s first heated to a tempera-1l ture of 450 - 550C, to ~hich is then added a silicone-base - 11 antifoamer at 5 - 20 ppm by weight Any one of known silicone-,f base antifoamers is usable in the practice of the invention, 20. Il however, because of an excellent thermal stability and a ¦¦ stability against decomposition ~y oxidation~ dimethyl-1I silicone oil-based antifoamer is prefera~le. The dimethyl-¦¦ silicone oil-based antifoamer i5 commercially available under ¦¦ the designations of, for Pxampler XSA-6402 (Tokyo Shibaura Electric Co., Ltd.), Narco~141 (~aroo Co., Ltd.) KF-96 ~1 I
Il l 7~
(composed of dimethylsilicone alone, product of Shinetsu Chem. Co., Ltd.), and ~S602 ~mixture oE dimethylsilicone oil and kerosene in a mixing ratio by weight of 50:50, product ~ of Shinetsu Chem. Co., Ltd.~. It should be noted that a 1 less amount than 5 ppm oE the silicone-based antifoamer does I hardly offer any effect of addition, while the addition of a il larger amount than 20 ppm can not be expected to increase ¦ its effect. T~us, the silicon-based antifoamer should be added in a range of 5 - 2Q ppm.
T~e heavy oil of 450 - 550C to which the silicone based anti~oamer has been added is introduced into a reaction vessel. In general, the hea~y oil containing the silicone- ¦
~ased antifoamer is continuously introduced into the reaction vessel from the lower section of the vessel. The thus intro-duced oil is contacted with superheated steam of 50Q - 800C
in the vessel to undergo the thermal cracking reaction. In ¦¦ this case, the superheated steam is lntroduced into the vessel separately from the heavy oil. By the thermal cracking, a ¦¦ cracked gas, a cracked oil and a petroleum pitch are produced~
20 1 No foaming is o~served during the cracking according to the process of the present invention.
The present in~ention will ~e particularly illustrated with reference to the accompanying drawing.
ll In the drawing, a raw ma~erial, the heavy petroleum oil 1, is heated in a heating furnace 2 up to a temperature 1.
IL:ll~767 ~
of 450 - 550C and then continuously fed into a reaction vessel 3 from a feed port 4 located at the ~ottom of the vessel 3. A silicone-based antifoamer is continuously fed to an outlet pipe of the furnace 2 from a storage tank 5 by means of a pump 6. Into the xeaction vessel 3 is continuously blo~n a large amount of superheated steam 7 of 500 - 800C from a feed port 8, so that the introduced heavy oil is contacted 1~ w~ith th~ superheated steam 7 In the vessel 3 to undergo a ¦¦ thermal cracking. The cracked gas.and cracked oil produced by the reaction are discharged together with the steam from a I discharge port 9, while the cracked residue ~petroleum pitch) ¦ is drawn from a recovery port lQ.
The continuous introduction of the antifoamer into . the outlet pipe of the furnace 2 as mentioned above will ¦ facilitate ~l~.rapid and uniform dispersion of the antifoamer in the heavy petroleum oil and also ~2) rapid and uniform contact of the antifoamer ~lth the foams due to the cracked oil f~eshly produced in the vessel 3 and due to superheated ¦ steam.
- 20 . In order to uniformly disperse the antifoamer in the produced cracked oil in the vessel 3, it is prefera le to mix the antifoamer sufficiently well with the heavy oil in the outlet pipe of the heating furnace 2,On the other hand, when exposed to a high temperature over a long time, the silicone-based antlfo3mer undergoes a thermal decomposition and lS
I converted into substances of low molecular weight, thus lowering ! or losing its antifoaming ability. Accordingly, it is prefera~le to shorten the residence time of the antifoamer l in the outlet pipe of the heating furnace 2.
In order to disperse the antifoamer in the raw material, the heavy petroleum oil, to a satisfactory extent, it will ¦~ suffice to increase the tur~ulence of the flo~ in the outlet ¦I pipe of the heating furnace 2 and to suitably select the residence time in that pipe. More particularly, it is desirable I to choose the diameter and length of the pipe so that the flo~ rate in the pipe is above 3Q m/sec and the residence time in the pipe is below 2 minutes.
Since the cracked oil freshly produced in the vessel 3 and the injected superheated steam cause the foaming, it is desirable to permit the antifoamer to rapidly contact ~rith the ~¦ foams of the cracked oil and superheated steam. To this end, the ra~ material, the heavy petroleum oiI, is introduced, as shown in the drawing, from the bottom of the reaction Il vessel 3 by the force o~ inertia while entraining the antifoamer ¦~ in the flo~ of the heavy oil to allow the antifoamer to be ¦¦ mixed ~ith or dispersed in the heavy oil to be cracked. In ~¦ order to more effectively disperse the newly introduced heavy ¦¦ petroleum oil into the heav~ o-~l which is beins cracked in the ¦¦ reaction vessel 3, it is preferable that the feed port 4 for the starting ol1 is inclined downward at an angle of 5 - 40 , ~lPa~7672 prefera~ly 5 - 15 , from the horizontal plane of the bottom of the reaction vessel 3. Alternatively~ a plurality of feed ports 4 may be provided or the flow of the starting oil Il in the pipe may be caused to swivel.
~ The amount of the antifoamer is, as defined herein- ¦
1 before, in the range of 5 ~ 20 ppm ~y weight of the starting Il heaYy petroleum oil and is suitahly selected within the above range dependtng on the type of the antifoamer, the type of the Il starting heavy petroleum oil to be treated and the cracklng conditi~ons.
¦ By the process according to the invention described ¦I hereinabove, the foaming during the thermal cracking of the heaYy petroleum oil under ~lowing of a large amount of super-¦! heated steam, ~hich has been considered to be difficultly ¦I prevented can ~e effectively suppressed or prevented.
~¦ In recent years, the thermal cracking process of the heavy ¦ petroleum oil has come more and more important and thus the ~ contribution of the process of the present invention to the i' industrial field is thought to be very large.
1I The present inventxon will ~e particularly described by way of the following example~
Example:
jl Vacuum residue of a raw oil respectivel~ from Khafji, Il Gach saran, Kuwait, and Ara~ian light was used as the staring ', heavy petroleum oil. The residue ~as thermally cracked in I, _ g ~ I
r~72 .
a system as shown in the accompanying drawing to produce a cracked gas, a cracked o~l and a petroleum pitch. That is, ¦¦ the starting residue oil was heated to about 50aoc in the Il heating furnace and fed into the bottom of the reaction ¦¦ vessel at a rate of 50 tons/hour.
dimethylsilicone~ased antifoamer ~XSA-6402, product of Tokyo Shi~aura Electric Co.~ Ltd~) was continuously added to the starting oil at the outlet pipe of the heating furnace at ¦ 10 ppm by weight. The heated heavy petroleum oil containing lQ the anti~oamer was introduced from the starting material feed port through the pipe, which had a bent portion inclined downward at an angle of lOq to the hirizontal plane, into the bottom of the reaction vessel at a flow rate of 40 - 50 m/sec in a residence time Cin the outlet pipe~ of below 10 seconds.
While, superheated steam ~700Cl was separately blown into the reaction vessel for thermally cracking the heavy petroleum oil at a temperature of 20~ - 500C. The cracking was carried out continuously in such a manner that the reactant ¦ heavy oil was invariably kept in the vessel at a level of 50 ¦ tons wh~le discharging the resulting carcked gas and oil from the upper section and the petroleum pitch from the discharge port at the bottom of the vessel.
¦¦ The degree of foaming of the reactant in the reaction ¦¦ vessel was determlned as follow-s: A plurality of radiation densimeters were provided at several locations of the vertical ~ 1~ ~
(pr~67~
zone along the length of the reaction vessel and the averaye densities of the oil at the respective heights oE the vessel ¦! were measured to determine the degree of foaming.
I ~ run of thermal cracking of the heavy petroleum oil was continued for 400Q hours. As a result, it was found that the foaming in the vessel could be suppressed to a satisfactory ¦l extent, ensuring a sta~le xun to produce a cracked oil, ¦ petroleum pitch, etc. During the run, no rlse in the internal ¦ pressure of the vessel was observed. In addition, no clogging lQ of the recovering pipe ~ith lumps of coke was recognized when the cracking residue was withdrawn from the bottom of the vessel.
Ater 4000 hours continuous run, the vessel was l inspected and the deposition of coke ~as hardl~ found on the lS inner wall of the g~s phase zone at the upper section of the vessel or on the inner wall of the discharge pipe for gas.
Il When the a~ove procedure ~as repeated either ~1) ¦ without use of any antifoamer or C2) using 10 ppm of the anti-,¦ foamer applied by a method ~herein it was sprayed from the 1I top of the ~essel, the internal pressure of the vessel was increased and the clogging of the plpe ~ith coke lumps frequently ¦ took place in 200 - 500 hours in the former case ~1) and in ¦ -¦ 500 - 800 hours in the latter case ~2). Hence, the test runs ¦ had to be stopped~
The inside of the vessel was inspected after the I
stopping of the runs. As a result, it was found that coke deposited in a thickenss of 500 - 1000 mm on the inner wall of the gas phase zone in the upper section of the vessel and in a thickness of 100 - 200 mm on the gas discharge port in each case.
From the above results, the superiority of the process of the present invention will be clear.
B~CKGROUN~ OF THE INVENTION:
A num~er of processes of thermally cracking a heavy i¦ petroleum oil are known including a process in which the ¦ heavy petroleum otl heated to 45~-550C is continuously ¦j charged into a reaction vessel for contact with a superheated I ¦ steam of 500-800~C therein, to undergo the thermal cracking to obtain a cracked gas / a cracked oil and a petroleum pitch.
In this process, however~ foams caused by evaporation of the thermally cracked oils and the employed steam tend to I accumulate in the bottom oil (composed of the raw material ¦ and cracked product, l.e. a mixture of the unreacted heavy petroleum o;~l and pitch~. As a result, there appears a l¦ phenomenon that the oil rises in foams in the reaction I li vessel. The foamtng of the bottom oil will undesirably involve I discharge of the kottom oil in large amount~ together with ¦I cracked gases, from an exhaust port located at the upper i section of the vessel. The bottom oil which is susceptible ¦ to coke is deposited in greatly increased amount on the ¦l inner wall o~ a gas discharge pipe connected to the discharge I port and also on the inner wall of the reaction vessel in a Il ~ 2 ~ `
IL~LQ76~
zone of gas phase at the upper section of the vessel. If a large amount of coke is formed and deposited on the inner wall of the vessel, the reaction vessel is reduced in its l effective capacity. This necessitates the use of a sufficiently 1 large-sized reaction vessel, inviting a great imposition from j a viewpoint of economy. Further, the deposition of coke on the inner wall of the reaction vessel will facilitate expansion of the heavy oil by the foaming, thus greatly increase the amount of deposltion of the formed coke. The coke deposited lQin a large amount often falls off from the inner wall in a form of lumps and is dropped into the heavy oil. This will frequently impede the withdrawal of the reaction residue (petro-leum pitch~ from the reaction vessel after completion of the reaction, and the petroleum pitch obtained becomes reduced I in quality due to contamination with such coke. On the other hand, if the coke is deposited on the inner wall of the exhaust ¦I pipe in a large amount, the discharge of gases is rendered ¦¦ difficult accompanying with an increased internal pressure I I of the reaction vessel, making the safe and continuous operation 20 ¦I Yery difficult.
¦¦ In order to overcome these disadvantages, there have ¦¦ been proposed a number of methods of preventing the foaming ¦¦ of the heavy oil upon the thermal cracking of the oil in a I I reaction vessel. For example, in a thermal cracking process ~5of heavy petroleur oll using a un~t such as delayed coker, I
11~7672 etc. a silicone-oased antiFoamer is sprayed into the vessel ¦¦ from the top thereof for a predetermined time after the Il ~oaming oE the heavy oil. However, the antifoaming treatment ¦¦ of the a~ove type can not o~tain a satisfactory effect when 5 ¦¦ applied to the thermal cracking process wherein a large amount of superheated steam is blown into the heavy petroleum ¦ oil for producing a Petroleum pitch, a cracked oil and a cracked gas.
SUMMARY 0~ THE INVENTION:
_. ... _ It is therefore an object of the present invention to proyide a process of the thermal cracking of a heavy petro-leum oil with a superheated steam, ~y which the foaming of the heavy oil occurring upon the thermal cracking can be very ¦ effectively prevented.
¦ Thls and other objects of the present invention will become apparent from the follo~ing detailed description.
In order to achieve the above object, we have made an extensive study on the cracking process and, as a result~
l found that when a heavy petroleum oil to which a predetermined ¦ amount o~ a silicone-based antifoamer has been added in advance is subjected to the thermal cracking by the afore-described prior technique-, the foaming of ~he heavy oil in the reaction ¦ vessel can be effectivel~ prevented. The process of the pre-¦¦ sent invention is based on this finding.
Accordin~ to the present invention, there is provided 11276~
a process for thermally cracking a heavy petroleum oil comprising heating the heavy petroleum oil to a temperature of 450-550C, adding a silicone-based antifoamer at 5 - 20ppm by weight to the heated oilS introducing the heated oil into a reaction ¦ vessel and contacting the oil with superheated steam of a temperature of 500 - 800C to effect the thermal cracking.
I BRIEF DESCRIPTION OF THE DRAWING^
.
The accompanying drawing is a flow chart showing one embodiment for carrying out the process for thermally cracking a heavy petroleum oil according to the invention.
: DETAILED DESCRIPTI3N OF THE INVENTION:
The heavy petroleum oil to be treated according to the process of the invention is not restrictive and includes, for example, a topped crude, a vacuum residue, a thermally cracked residue and other various petroleu~ residue oils. In practice, the heavy petroleum oil 1s first heated to a tempera-1l ture of 450 - 550C, to ~hich is then added a silicone-base - 11 antifoamer at 5 - 20 ppm by weight Any one of known silicone-,f base antifoamers is usable in the practice of the invention, 20. Il however, because of an excellent thermal stability and a ¦¦ stability against decomposition ~y oxidation~ dimethyl-1I silicone oil-based antifoamer is prefera~le. The dimethyl-¦¦ silicone oil-based antifoamer i5 commercially available under ¦¦ the designations of, for Pxampler XSA-6402 (Tokyo Shibaura Electric Co., Ltd.), Narco~141 (~aroo Co., Ltd.) KF-96 ~1 I
Il l 7~
(composed of dimethylsilicone alone, product of Shinetsu Chem. Co., Ltd.), and ~S602 ~mixture oE dimethylsilicone oil and kerosene in a mixing ratio by weight of 50:50, product ~ of Shinetsu Chem. Co., Ltd.~. It should be noted that a 1 less amount than 5 ppm oE the silicone-based antifoamer does I hardly offer any effect of addition, while the addition of a il larger amount than 20 ppm can not be expected to increase ¦ its effect. T~us, the silicon-based antifoamer should be added in a range of 5 - 2Q ppm.
T~e heavy oil of 450 - 550C to which the silicone based anti~oamer has been added is introduced into a reaction vessel. In general, the hea~y oil containing the silicone- ¦
~ased antifoamer is continuously introduced into the reaction vessel from the lower section of the vessel. The thus intro-duced oil is contacted with superheated steam of 50Q - 800C
in the vessel to undergo the thermal cracking reaction. In ¦¦ this case, the superheated steam is lntroduced into the vessel separately from the heavy oil. By the thermal cracking, a ¦¦ cracked gas, a cracked oil and a petroleum pitch are produced~
20 1 No foaming is o~served during the cracking according to the process of the present invention.
The present in~ention will ~e particularly illustrated with reference to the accompanying drawing.
ll In the drawing, a raw ma~erial, the heavy petroleum oil 1, is heated in a heating furnace 2 up to a temperature 1.
IL:ll~767 ~
of 450 - 550C and then continuously fed into a reaction vessel 3 from a feed port 4 located at the ~ottom of the vessel 3. A silicone-based antifoamer is continuously fed to an outlet pipe of the furnace 2 from a storage tank 5 by means of a pump 6. Into the xeaction vessel 3 is continuously blo~n a large amount of superheated steam 7 of 500 - 800C from a feed port 8, so that the introduced heavy oil is contacted 1~ w~ith th~ superheated steam 7 In the vessel 3 to undergo a ¦¦ thermal cracking. The cracked gas.and cracked oil produced by the reaction are discharged together with the steam from a I discharge port 9, while the cracked residue ~petroleum pitch) ¦ is drawn from a recovery port lQ.
The continuous introduction of the antifoamer into . the outlet pipe of the furnace 2 as mentioned above will ¦ facilitate ~l~.rapid and uniform dispersion of the antifoamer in the heavy petroleum oil and also ~2) rapid and uniform contact of the antifoamer ~lth the foams due to the cracked oil f~eshly produced in the vessel 3 and due to superheated ¦ steam.
- 20 . In order to uniformly disperse the antifoamer in the produced cracked oil in the vessel 3, it is prefera le to mix the antifoamer sufficiently well with the heavy oil in the outlet pipe of the heating furnace 2,On the other hand, when exposed to a high temperature over a long time, the silicone-based antlfo3mer undergoes a thermal decomposition and lS
I converted into substances of low molecular weight, thus lowering ! or losing its antifoaming ability. Accordingly, it is prefera~le to shorten the residence time of the antifoamer l in the outlet pipe of the heating furnace 2.
In order to disperse the antifoamer in the raw material, the heavy petroleum oil, to a satisfactory extent, it will ¦~ suffice to increase the tur~ulence of the flo~ in the outlet ¦I pipe of the heating furnace 2 and to suitably select the residence time in that pipe. More particularly, it is desirable I to choose the diameter and length of the pipe so that the flo~ rate in the pipe is above 3Q m/sec and the residence time in the pipe is below 2 minutes.
Since the cracked oil freshly produced in the vessel 3 and the injected superheated steam cause the foaming, it is desirable to permit the antifoamer to rapidly contact ~rith the ~¦ foams of the cracked oil and superheated steam. To this end, the ra~ material, the heavy petroleum oiI, is introduced, as shown in the drawing, from the bottom of the reaction Il vessel 3 by the force o~ inertia while entraining the antifoamer ¦~ in the flo~ of the heavy oil to allow the antifoamer to be ¦¦ mixed ~ith or dispersed in the heavy oil to be cracked. In ~¦ order to more effectively disperse the newly introduced heavy ¦¦ petroleum oil into the heav~ o-~l which is beins cracked in the ¦¦ reaction vessel 3, it is preferable that the feed port 4 for the starting ol1 is inclined downward at an angle of 5 - 40 , ~lPa~7672 prefera~ly 5 - 15 , from the horizontal plane of the bottom of the reaction vessel 3. Alternatively~ a plurality of feed ports 4 may be provided or the flow of the starting oil Il in the pipe may be caused to swivel.
~ The amount of the antifoamer is, as defined herein- ¦
1 before, in the range of 5 ~ 20 ppm ~y weight of the starting Il heaYy petroleum oil and is suitahly selected within the above range dependtng on the type of the antifoamer, the type of the Il starting heavy petroleum oil to be treated and the cracklng conditi~ons.
¦ By the process according to the invention described ¦I hereinabove, the foaming during the thermal cracking of the heaYy petroleum oil under ~lowing of a large amount of super-¦! heated steam, ~hich has been considered to be difficultly ¦I prevented can ~e effectively suppressed or prevented.
~¦ In recent years, the thermal cracking process of the heavy ¦ petroleum oil has come more and more important and thus the ~ contribution of the process of the present invention to the i' industrial field is thought to be very large.
1I The present inventxon will ~e particularly described by way of the following example~
Example:
jl Vacuum residue of a raw oil respectivel~ from Khafji, Il Gach saran, Kuwait, and Ara~ian light was used as the staring ', heavy petroleum oil. The residue ~as thermally cracked in I, _ g ~ I
r~72 .
a system as shown in the accompanying drawing to produce a cracked gas, a cracked o~l and a petroleum pitch. That is, ¦¦ the starting residue oil was heated to about 50aoc in the Il heating furnace and fed into the bottom of the reaction ¦¦ vessel at a rate of 50 tons/hour.
dimethylsilicone~ased antifoamer ~XSA-6402, product of Tokyo Shi~aura Electric Co.~ Ltd~) was continuously added to the starting oil at the outlet pipe of the heating furnace at ¦ 10 ppm by weight. The heated heavy petroleum oil containing lQ the anti~oamer was introduced from the starting material feed port through the pipe, which had a bent portion inclined downward at an angle of lOq to the hirizontal plane, into the bottom of the reaction vessel at a flow rate of 40 - 50 m/sec in a residence time Cin the outlet pipe~ of below 10 seconds.
While, superheated steam ~700Cl was separately blown into the reaction vessel for thermally cracking the heavy petroleum oil at a temperature of 20~ - 500C. The cracking was carried out continuously in such a manner that the reactant ¦ heavy oil was invariably kept in the vessel at a level of 50 ¦ tons wh~le discharging the resulting carcked gas and oil from the upper section and the petroleum pitch from the discharge port at the bottom of the vessel.
¦¦ The degree of foaming of the reactant in the reaction ¦¦ vessel was determlned as follow-s: A plurality of radiation densimeters were provided at several locations of the vertical ~ 1~ ~
(pr~67~
zone along the length of the reaction vessel and the averaye densities of the oil at the respective heights oE the vessel ¦! were measured to determine the degree of foaming.
I ~ run of thermal cracking of the heavy petroleum oil was continued for 400Q hours. As a result, it was found that the foaming in the vessel could be suppressed to a satisfactory ¦l extent, ensuring a sta~le xun to produce a cracked oil, ¦ petroleum pitch, etc. During the run, no rlse in the internal ¦ pressure of the vessel was observed. In addition, no clogging lQ of the recovering pipe ~ith lumps of coke was recognized when the cracking residue was withdrawn from the bottom of the vessel.
Ater 4000 hours continuous run, the vessel was l inspected and the deposition of coke ~as hardl~ found on the lS inner wall of the g~s phase zone at the upper section of the vessel or on the inner wall of the discharge pipe for gas.
Il When the a~ove procedure ~as repeated either ~1) ¦ without use of any antifoamer or C2) using 10 ppm of the anti-,¦ foamer applied by a method ~herein it was sprayed from the 1I top of the ~essel, the internal pressure of the vessel was increased and the clogging of the plpe ~ith coke lumps frequently ¦ took place in 200 - 500 hours in the former case ~1) and in ¦ -¦ 500 - 800 hours in the latter case ~2). Hence, the test runs ¦ had to be stopped~
The inside of the vessel was inspected after the I
stopping of the runs. As a result, it was found that coke deposited in a thickenss of 500 - 1000 mm on the inner wall of the gas phase zone in the upper section of the vessel and in a thickness of 100 - 200 mm on the gas discharge port in each case.
From the above results, the superiority of the process of the present invention will be clear.
Claims (2)
1. In a process for thermally cracking a heavy petroleum oil by heating the heavy petroleum oil to a tempera-ture of 450-550°C and introducing the thus heated heavy petroleum oil into a reaction vessel in which the heavy petroleum oil is contacted with a superheated steam of 500-800°C to undergo a thermall cracking reaction, the improvement comprising:
adding 5 - 20 ppm by weight of a silicone-based antifoamer to the heavy petroleum oil prior to the introduction into said reaction vessel from the bottom thereof.
adding 5 - 20 ppm by weight of a silicone-based antifoamer to the heavy petroleum oil prior to the introduction into said reaction vessel from the bottom thereof.
2. A process according to Claim 1, wherein said silicone-base antifoamer is a dimethyl silicone oil-based antifoamer.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP84044/1977 | 1977-07-15 | ||
| JP8404477A JPS5420006A (en) | 1977-07-15 | 1977-07-15 | Method of preventing foaming of heavy oil |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1107672A true CA1107672A (en) | 1981-08-25 |
Family
ID=13819501
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA307,370A Expired CA1107672A (en) | 1977-07-15 | 1978-07-14 | Process for thermally cracking heavy petroleum oil |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS5420006A (en) |
| CA (1) | CA1107672A (en) |
| FR (1) | FR2397450A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2072603A1 (en) * | 2006-09-28 | 2009-06-24 | Chiyoda Corporation | Method of thermal cracking processing, thermal cracking reaction vessel and thermal cracking processing apparatus for petroleum heavy oil |
| US7575669B2 (en) | 2002-06-26 | 2009-08-18 | Dorf Ketal Chemicals, Llc | Method of removal of carbonyl compounds along with acid gases from cracked gas in ethylene process |
| US7906012B2 (en) | 2002-07-16 | 2011-03-15 | Dorf Ketal Chemicals India Pvt. Ltd. | Method for reducing foam in a primary fractionator |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7093207B2 (en) * | 2018-03-27 | 2022-06-29 | コスモ石油株式会社 | Method for Quantifying Silicon Element in Heavy Nafsa and Method for Producing Heavy Nafsa |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB357265A (en) * | 1929-06-24 | 1931-09-24 | Petroleum Conversion Corp | Improvements in and relating to oil treatment |
| GB876263A (en) * | 1959-03-04 | 1961-08-30 | Belge Produits Chimiques Sa | A process and apparatus for protecting the internal surface of the walls of a pyrolysis chamber in a furnace for the thermal treatment of hydrocarbons |
| NL277655A (en) * | 1961-07-17 | |||
| SU518959A1 (en) * | 1974-06-18 | 1978-02-25 | Предприятие П/Я А-3483 | Method of heat retreatment of hydrocarbon raw material |
-
1977
- 1977-07-15 JP JP8404477A patent/JPS5420006A/en active Granted
-
1978
- 1978-07-13 FR FR7820981A patent/FR2397450A1/en active Granted
- 1978-07-14 CA CA307,370A patent/CA1107672A/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7575669B2 (en) | 2002-06-26 | 2009-08-18 | Dorf Ketal Chemicals, Llc | Method of removal of carbonyl compounds along with acid gases from cracked gas in ethylene process |
| US7906012B2 (en) | 2002-07-16 | 2011-03-15 | Dorf Ketal Chemicals India Pvt. Ltd. | Method for reducing foam in a primary fractionator |
| EP2072603A1 (en) * | 2006-09-28 | 2009-06-24 | Chiyoda Corporation | Method of thermal cracking processing, thermal cracking reaction vessel and thermal cracking processing apparatus for petroleum heavy oil |
| EP2072603A4 (en) * | 2006-09-28 | 2014-03-12 | Chiyoda Corp | Method of thermal cracking processing, thermal cracking reaction vessel and thermal cracking processing apparatus for petroleum heavy oil |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5745277B2 (en) | 1982-09-27 |
| FR2397450B1 (en) | 1982-11-05 |
| FR2397450A1 (en) | 1979-02-09 |
| JPS5420006A (en) | 1979-02-15 |
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