CA1180975A - Composition and method for controlling foaming in delayed coking process - Google Patents
Composition and method for controlling foaming in delayed coking processInfo
- Publication number
- CA1180975A CA1180975A CA000386825A CA386825A CA1180975A CA 1180975 A CA1180975 A CA 1180975A CA 000386825 A CA000386825 A CA 000386825A CA 386825 A CA386825 A CA 386825A CA 1180975 A CA1180975 A CA 1180975A
- Authority
- CA
- Canada
- Prior art keywords
- composition
- foaming
- weight
- delayed coking
- coking
- 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
- C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
- C10B57/00—Other carbonising or coking processes; Features of destructive distillation processes in general
- C10B57/04—Other carbonising or coking processes; Features of destructive distillation processes in general using charges of special composition
- C10B57/06—Other carbonising or coking processes; Features of destructive distillation processes in general using charges of special composition containing additives
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
- C10B55/00—Coking mineral oils, bitumen, tar, and the like or mixtures thereof with solid carbonaceous material
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Dispersion Chemistry (AREA)
- Degasification And Air Bubble Elimination (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
Abstract of the Disclosure A defoaming composition comprising an organo siloxane polymer, an aliphatic alcohol such as 2-ethylhexanol and, optionally, a liquid carrier which can be added to a coking drum in a delayed coking process to reduce foaming. In cases where the feed stock used in the delayed coking process contains greater than one half percent total sulfur, defoaming in the coking drum can be accomplished by adding an aliphatic alcohol such as 2-ethylhexanol.
Description
Back~ ound o~ the Invention qhe present invention relates to compositions and mcthods for controlling foaming in delayed coking operations.
In refinery operations designed to obtain the yreatest yield of gasoline, the end residue is generally coke rather than a residual oil, the coke being derived from dclayed coking operations. Typically, heavy products such as vacuum tower bottoms or gas oil recycle streams comprise the charge feed to a delayed coking process. The high boiling charge feed is heated to a temperature of between 700-1000F and then fed into a coking drum. The preheating of the charge feed supplies the heat necessary in the coking drum to crack high molecular weight~
hydrocarbons, and volatilize the lighter components e.g. the naphtha fraction. A fractionator is used to separate the naphtha fraction and perhaps a catalytic cracker feed fraction recovered from the charge feed to the coking drum. Because of `the nature of the components present in the charge feed to the coking drum, there is a tendency, on occasion~ for foaming to occur in the coking drum. Foaming can disrupt operation of the fractionator and result in carry over of unwanted components with the fractions removed from the fractionator To control the foaming, it is common practice to add a liquid silicone defoaming agent to the charge feed. This has several dis-advantages. For one, silicone defoamers are quite expensive.
Additionally, there is frequently carry over of the silicone defoamer in the fractions recovered from the fractionator. If these fractions are subsequently used as feed stocks for reforming units, poisoning of the reforming catalyst can result.
Summary of the Invention It is therefore an object of the present invention to provide an improved method for preventing foaming in delayed coking process.
~ further object of the present invention is to provide a new defoaming composition espeeially suited for use in a delayed coking operation.
In accordance with the above objects, there is pro-vided r in one embodiment a compositicn for use as an anti-foaming agent consisting essentially of from about 0.1 to about 20% by weight of a liquid organo-siloxane polymer having the general formula (R2SiO)n, wherein R is a lower alkyl radical, said polymer having a viscosity ranging from about 8000 to about lOO,OQ0 centistokes, and from about 20% to about 60% by weight of a C6-C12 range aliphatie alcohol t and from about 20% to about 60% by weight of a liquid organic carrier in which said siloxane polymer and said aleohol are soluble and whieh is generally inert to reaction in a delayed coking operation.
In another embodiment of the present invention the above composition containing the siloxane polymer and the - aliphatie aleohol, preferably with a earrier, are added to a coking drum used in a delayed eoking process in an amount sufficient to control foaming in the eoking drum.
In a further embodiment of the present invention, a eomposition eomprised of one of the above named aliphatie alcohols preferably in a solvent or earrier such as a polyol is added, in an effective amount, to a coking drum to control foaming.
r ~
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7~i B_ief Descr iption__f the Drawing The single igure is a simplified schematic flow diagram of a typical delayed coking process.
~8()~
Description of the Preferred Embodiments The novel defoamirlg compositions of ttle present invention contain an organo siloxanc polymer, and an aliphatic alcohol.
The organo siloxane po~ymer, commonly referred to as a sili-cone, has the general structure ~R2SiO)n wherein R is an organic radical such as, for example, methyl, ethyl, pro~yl, etc.
Especially preferred are dimethyl polysiloxanes such as, for example, dimethyl silicone fluids sold under the trademark Viscasil marketed by General Electric Company. The or~anic siloxane polymers useful in the present invention are those 10 having viscosities ranging from around 8,000 to about 100,000 centistokes, preferably from about 10,000 to 60,000 centi--stokes, especially around 12,S00 centistokes. The organo siloxane polymer will be present in the composition of the present invention in amounts ranging from about 0.1 to about 20%
by weight. It is a particular feature of the present invention that the silicone containing anti-foaming compositions of the present invention are low in silicones but still provide the same foam control properties at the same injection rates as prior art concentrated silicone products. As previously noted, such concentrated silicone based materials tend to migrate to the naphtha fractions removed from the delayed coking process and can lead to downstream catalyst poisoning in reformers and the like.
The other component of the novel silicone containing compositions of the present invention is an aliphatic alcohol having from about 6 to about 12 carbon atoms. Non-limiting examples of such alcohols include hexanol, heptanol, octanol, 2-ethylhexanol, decanol, etc. Especially preferred as an alcohol is 2-ethylhexanol. The aliphatic alcohol will be present in the silicone containing composition of the present invention in amounts of from about 20 to about 60% by weight.
The novel compositions of the present invention preferably also contain a carrier or solvent for the siloxane polymer and alcohol. Suitable solvents or carriers include kerosene, naphtha, aliphatic hydrocarbons containing from 6 to 3~7~
12 carbon atoms, diesel oil, and other petroleum distillates in which the silox~nc and the alcohol are soluble. Generally speaking, the carrier or solvent can comprise any organic liquid in ~hich the siloxane polymer and the alcohol are soluble, which is generally inert in the sense that it has no deleterious effect on the delayed coking operation or reacts with the siloxane polymer and/or the alcohol. A particularly desirable solvent or carrier comprises a polyol produced by reacting dipropylene glycol with propylene oxide or ethylene o~ide until a polyol is produced having the desired molecular weight, e.g. from about 1,000 to about 3,000, especially around 2,000. The polyols useful in the present invention can be represented by the following formula:
CH3-cH-cH2-o-cH2-c~l-c~3 Rl-CH ~ CH-I~
CH~ CH2 O O
~ L__~ x ~----H Y
wherein Rl and R2 can be methyl or hydrogen and the sum of X
Y is from about 30 to about 45. An especially preferred polyol is one having the above formula wherein Rl and R2 are methyl groups and the molecular weight is around 2,000. When a carrier or solvent is used, it wil~ be present in the sllicone con-taining compositions of the present invention in amounts offrom about 20 to about 60% by weight.
The composition described above containing the organo -siloxane polymer, the aliphatic alcohol and optionally, the carrier is especially useful in delayed coking operations when the charge feed to the coking drum contains less than about 1/2~
by weight sulphur~ In cases where the charge feed contains greater than 1/2Q by weight sulphur, foaming in the delayed coking process can be controlled either by the silicone con-taining composition or simply by the addition of an effective amount of the above described aliphatic alcohol. Preferably for ease of addition, the alcohol is added as a composition ccmprised of from about 20 to about 60~ by ~eigi-lt alcohol arld from about 80 to about ~0~ by weight of onc of the above-described carriers.
To more fully illustrate t~le method of the present invention, reference is had to the accompanying drawing. A
charge feed is inteoduced via pump 10 and line 12 into a heater 14. The charge feed will normally comprise heavy ends from various refinery operations such as vacuum tower bottoms, gas oil recycle streams, or shale oils, coal tar pitch, etc. In heater 14, the charge feed is raised to a temperature in the range of from about 700 to 1,000~ and is introduced via line 16 into a coking drum 18. ~hile for simplicity, only one coking drum is shown, it will be understood, as well known to those skilled in the art, that in a typical delayed coking process at least two drums are employed, one of which is filling while the other is being decoked. Indeed, many delayed coking processes employ four or more drums. Preheating of the charge feed in heater 14 supplies the heat necessary to carry out distillation and co~ing in drum 1~. Volatiles from the charge feed in drum 18 pass via line 20 into a fractionator 22. Coke produced in drum 1~ is removed from the bottom thereof via line 24.
In rractionator 22, several streams are produced. An overhead fraction, removed via line 24 is condensed in con-denser 26 and collected in an accumulator drum 28. From accumulator 28, a light gas fraction, e.g. ethane, pro~ane, etc., is removed via line 30 while a heavier, liquid, light oil fraction is removed via line 32 and sent via pump 34 for further processing. A heavy oil, bottoms fraction i5 removed from fractionator 22 via line 36 and pump 3~ and also sent for ~urther processing or end use via line ~0. In typical delayed coking operations, without the addition of a defoaming agent, it is possible for foam to disrupt the operation offractionator 22 resulting in a carry over of unwanted impurities into the streams leaving via lines 2~ and 36. In the method of the present invention, this foaming is controlled either ~y the addition of the novel defoamer composition comprised of the g~
organo siloxane polymer and the aliphatic alcohol, orr in cases where the charge feed contains greater than ~ 6 b~ weight sulphur, by the addition of the above d~scribed aliphatic alcohol, preferably with a carrier. The defoamer may be introduced directly into coking drum 18 via line 42 through valve ~4 or, alternatively admixed, via line 46 and valve 48, with the heated charge feed passing through line 16 into coking drum 18. In either event, the amount of defoamer added will depend on the foaming conditions existing in coking drum 18~
As indicated~ the precise amount of the defoaming agent added to the coking drum will depend upon the foaming conditions in the coking drum. However, in a typical delayed coking process it is common to add an amount of defoamer ranging from about 1 to about 24 pounds (from about 0.1 to about 3 gallons) per hundred tons of coke produced. The amount of coke produced in a typical delayed coking operation can be easily predicted from the operating conditions of the coking process and the composition of the charge feed. Accordingly, as is well known to those skilled i~ the art, the precise amount of defoamer to be added in any yiven delayed coking operation can be easily determined. The defoaming agent is conveniently added to the -coking drum in admixture with a hydrocarbon diluent such as the light oil being removed via line 32 from drum 28. It has been found, for example, that the defoamer can be mixed in a 1 to 3
In refinery operations designed to obtain the yreatest yield of gasoline, the end residue is generally coke rather than a residual oil, the coke being derived from dclayed coking operations. Typically, heavy products such as vacuum tower bottoms or gas oil recycle streams comprise the charge feed to a delayed coking process. The high boiling charge feed is heated to a temperature of between 700-1000F and then fed into a coking drum. The preheating of the charge feed supplies the heat necessary in the coking drum to crack high molecular weight~
hydrocarbons, and volatilize the lighter components e.g. the naphtha fraction. A fractionator is used to separate the naphtha fraction and perhaps a catalytic cracker feed fraction recovered from the charge feed to the coking drum. Because of `the nature of the components present in the charge feed to the coking drum, there is a tendency, on occasion~ for foaming to occur in the coking drum. Foaming can disrupt operation of the fractionator and result in carry over of unwanted components with the fractions removed from the fractionator To control the foaming, it is common practice to add a liquid silicone defoaming agent to the charge feed. This has several dis-advantages. For one, silicone defoamers are quite expensive.
Additionally, there is frequently carry over of the silicone defoamer in the fractions recovered from the fractionator. If these fractions are subsequently used as feed stocks for reforming units, poisoning of the reforming catalyst can result.
Summary of the Invention It is therefore an object of the present invention to provide an improved method for preventing foaming in delayed coking process.
~ further object of the present invention is to provide a new defoaming composition espeeially suited for use in a delayed coking operation.
In accordance with the above objects, there is pro-vided r in one embodiment a compositicn for use as an anti-foaming agent consisting essentially of from about 0.1 to about 20% by weight of a liquid organo-siloxane polymer having the general formula (R2SiO)n, wherein R is a lower alkyl radical, said polymer having a viscosity ranging from about 8000 to about lOO,OQ0 centistokes, and from about 20% to about 60% by weight of a C6-C12 range aliphatie alcohol t and from about 20% to about 60% by weight of a liquid organic carrier in which said siloxane polymer and said aleohol are soluble and whieh is generally inert to reaction in a delayed coking operation.
In another embodiment of the present invention the above composition containing the siloxane polymer and the - aliphatie aleohol, preferably with a earrier, are added to a coking drum used in a delayed eoking process in an amount sufficient to control foaming in the eoking drum.
In a further embodiment of the present invention, a eomposition eomprised of one of the above named aliphatie alcohols preferably in a solvent or earrier such as a polyol is added, in an effective amount, to a coking drum to control foaming.
r ~
.~.
7~i B_ief Descr iption__f the Drawing The single igure is a simplified schematic flow diagram of a typical delayed coking process.
~8()~
Description of the Preferred Embodiments The novel defoamirlg compositions of ttle present invention contain an organo siloxanc polymer, and an aliphatic alcohol.
The organo siloxane po~ymer, commonly referred to as a sili-cone, has the general structure ~R2SiO)n wherein R is an organic radical such as, for example, methyl, ethyl, pro~yl, etc.
Especially preferred are dimethyl polysiloxanes such as, for example, dimethyl silicone fluids sold under the trademark Viscasil marketed by General Electric Company. The or~anic siloxane polymers useful in the present invention are those 10 having viscosities ranging from around 8,000 to about 100,000 centistokes, preferably from about 10,000 to 60,000 centi--stokes, especially around 12,S00 centistokes. The organo siloxane polymer will be present in the composition of the present invention in amounts ranging from about 0.1 to about 20%
by weight. It is a particular feature of the present invention that the silicone containing anti-foaming compositions of the present invention are low in silicones but still provide the same foam control properties at the same injection rates as prior art concentrated silicone products. As previously noted, such concentrated silicone based materials tend to migrate to the naphtha fractions removed from the delayed coking process and can lead to downstream catalyst poisoning in reformers and the like.
The other component of the novel silicone containing compositions of the present invention is an aliphatic alcohol having from about 6 to about 12 carbon atoms. Non-limiting examples of such alcohols include hexanol, heptanol, octanol, 2-ethylhexanol, decanol, etc. Especially preferred as an alcohol is 2-ethylhexanol. The aliphatic alcohol will be present in the silicone containing composition of the present invention in amounts of from about 20 to about 60% by weight.
The novel compositions of the present invention preferably also contain a carrier or solvent for the siloxane polymer and alcohol. Suitable solvents or carriers include kerosene, naphtha, aliphatic hydrocarbons containing from 6 to 3~7~
12 carbon atoms, diesel oil, and other petroleum distillates in which the silox~nc and the alcohol are soluble. Generally speaking, the carrier or solvent can comprise any organic liquid in ~hich the siloxane polymer and the alcohol are soluble, which is generally inert in the sense that it has no deleterious effect on the delayed coking operation or reacts with the siloxane polymer and/or the alcohol. A particularly desirable solvent or carrier comprises a polyol produced by reacting dipropylene glycol with propylene oxide or ethylene o~ide until a polyol is produced having the desired molecular weight, e.g. from about 1,000 to about 3,000, especially around 2,000. The polyols useful in the present invention can be represented by the following formula:
CH3-cH-cH2-o-cH2-c~l-c~3 Rl-CH ~ CH-I~
CH~ CH2 O O
~ L__~ x ~----H Y
wherein Rl and R2 can be methyl or hydrogen and the sum of X
Y is from about 30 to about 45. An especially preferred polyol is one having the above formula wherein Rl and R2 are methyl groups and the molecular weight is around 2,000. When a carrier or solvent is used, it wil~ be present in the sllicone con-taining compositions of the present invention in amounts offrom about 20 to about 60% by weight.
The composition described above containing the organo -siloxane polymer, the aliphatic alcohol and optionally, the carrier is especially useful in delayed coking operations when the charge feed to the coking drum contains less than about 1/2~
by weight sulphur~ In cases where the charge feed contains greater than 1/2Q by weight sulphur, foaming in the delayed coking process can be controlled either by the silicone con-taining composition or simply by the addition of an effective amount of the above described aliphatic alcohol. Preferably for ease of addition, the alcohol is added as a composition ccmprised of from about 20 to about 60~ by ~eigi-lt alcohol arld from about 80 to about ~0~ by weight of onc of the above-described carriers.
To more fully illustrate t~le method of the present invention, reference is had to the accompanying drawing. A
charge feed is inteoduced via pump 10 and line 12 into a heater 14. The charge feed will normally comprise heavy ends from various refinery operations such as vacuum tower bottoms, gas oil recycle streams, or shale oils, coal tar pitch, etc. In heater 14, the charge feed is raised to a temperature in the range of from about 700 to 1,000~ and is introduced via line 16 into a coking drum 18. ~hile for simplicity, only one coking drum is shown, it will be understood, as well known to those skilled in the art, that in a typical delayed coking process at least two drums are employed, one of which is filling while the other is being decoked. Indeed, many delayed coking processes employ four or more drums. Preheating of the charge feed in heater 14 supplies the heat necessary to carry out distillation and co~ing in drum 1~. Volatiles from the charge feed in drum 18 pass via line 20 into a fractionator 22. Coke produced in drum 1~ is removed from the bottom thereof via line 24.
In rractionator 22, several streams are produced. An overhead fraction, removed via line 24 is condensed in con-denser 26 and collected in an accumulator drum 28. From accumulator 28, a light gas fraction, e.g. ethane, pro~ane, etc., is removed via line 30 while a heavier, liquid, light oil fraction is removed via line 32 and sent via pump 34 for further processing. A heavy oil, bottoms fraction i5 removed from fractionator 22 via line 36 and pump 3~ and also sent for ~urther processing or end use via line ~0. In typical delayed coking operations, without the addition of a defoaming agent, it is possible for foam to disrupt the operation offractionator 22 resulting in a carry over of unwanted impurities into the streams leaving via lines 2~ and 36. In the method of the present invention, this foaming is controlled either ~y the addition of the novel defoamer composition comprised of the g~
organo siloxane polymer and the aliphatic alcohol, orr in cases where the charge feed contains greater than ~ 6 b~ weight sulphur, by the addition of the above d~scribed aliphatic alcohol, preferably with a carrier. The defoamer may be introduced directly into coking drum 18 via line 42 through valve ~4 or, alternatively admixed, via line 46 and valve 48, with the heated charge feed passing through line 16 into coking drum 18. In either event, the amount of defoamer added will depend on the foaming conditions existing in coking drum 18~
As indicated~ the precise amount of the defoaming agent added to the coking drum will depend upon the foaming conditions in the coking drum. However, in a typical delayed coking process it is common to add an amount of defoamer ranging from about 1 to about 24 pounds (from about 0.1 to about 3 gallons) per hundred tons of coke produced. The amount of coke produced in a typical delayed coking operation can be easily predicted from the operating conditions of the coking process and the composition of the charge feed. Accordingly, as is well known to those skilled i~ the art, the precise amount of defoamer to be added in any yiven delayed coking operation can be easily determined. The defoaming agent is conveniently added to the -coking drum in admixture with a hydrocarbon diluent such as the light oil being removed via line 32 from drum 28. It has been found, for example, that the defoamer can be mixed in a 1 to 3
2; weight ratio with such light oil recovered from the delayed cokinq process and that mixture conveniently added to control foaming.
Example 1 A defoamer comprising 50% by weight of a polyol having a molecular weight of 2,000 and 50% by weight of 2-ethylhexanol was admixed in a 1 to 3 ratio with a distilate from the delayed coking drum. The mixture was injected into the coking drum when foam was present. The total charge to the coking drum was 4,180 barrels comprised of 3,580 barrels of vacuum tar bottoms and G00 barrels of gas oil recycle. The temperature of the charge feed to the coking drum was 927F. Approximately ~0 pounds of the 7~
defoamin~ agent was added to the co~e drum during a 20 hour cycle of thc process. The deoaming ac~ent was added to t~
coking drum by means of a chernical pump which pumped the defoaming mixture through a nozzle in the top of the drum. It was noted that the defoaming agent containing no silicolle prevented any substantial foaming.
Example 2 The procedure of Example 1 was followed with the exception that thc defoarner used comprised 10% by weight dimethyl poly-10 siloxane, 40% by weight 2-ethyl~exanol and 60% by weight kerosene. Foaming in the coking drum was substantially prevented.
_ample 3 The procedure of Example 1 is followed with the exception that the defoamer used comprises 2-ethylhexanol added without any carrier. No substantial foaming in the coking drum is observed.
As previously noted, the method of the present invention wherein a non-silicone based defoaming agent is used has considerable advantage. For one, the cost of silicone based defoaming agents is considerably higher than that of the non-silicone based defoaming agent used in the method of the present invention. Additionally, because no sillcone is present, there is no risk that- the distillates recovered from the delayed coking process will be contaminated with silicone which can cause downstream catalyst poisoning. While the non-silicone based defoaming agent described herein can be used with charge feeds having greater than 1/2% by weight sulphur, when the sulphur content is less than 1/2% by weight, it is necessary to use the novel silicone-containing composition of the preserlt invention. However~ even in this case, considerable advantage is realized as compared with conventional concentrated sili-cone defoamers. The silicone defoamer of the present invention, although containing much less silicone, produces the same foam control proper~ies as concentrated silicone products while minimizing the principal disadvantages involved 9~,~
with the use of such concentrated silicones. Specifically, since the silicone defoamers of the present invention contain only a small quantity of the organo siloxane polymer, there is less chance that silicone materials will migrate to the dis~illate fractions recovered from the coking drum.
Accordingly, there is less chance of downstream catalyst poisoning in the subsequent processing of the streams.
I'he invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are there-fore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalence of the claims are therefore intended to be embraced therein.
Example 1 A defoamer comprising 50% by weight of a polyol having a molecular weight of 2,000 and 50% by weight of 2-ethylhexanol was admixed in a 1 to 3 ratio with a distilate from the delayed coking drum. The mixture was injected into the coking drum when foam was present. The total charge to the coking drum was 4,180 barrels comprised of 3,580 barrels of vacuum tar bottoms and G00 barrels of gas oil recycle. The temperature of the charge feed to the coking drum was 927F. Approximately ~0 pounds of the 7~
defoamin~ agent was added to the co~e drum during a 20 hour cycle of thc process. The deoaming ac~ent was added to t~
coking drum by means of a chernical pump which pumped the defoaming mixture through a nozzle in the top of the drum. It was noted that the defoaming agent containing no silicolle prevented any substantial foaming.
Example 2 The procedure of Example 1 was followed with the exception that thc defoarner used comprised 10% by weight dimethyl poly-10 siloxane, 40% by weight 2-ethyl~exanol and 60% by weight kerosene. Foaming in the coking drum was substantially prevented.
_ample 3 The procedure of Example 1 is followed with the exception that the defoamer used comprises 2-ethylhexanol added without any carrier. No substantial foaming in the coking drum is observed.
As previously noted, the method of the present invention wherein a non-silicone based defoaming agent is used has considerable advantage. For one, the cost of silicone based defoaming agents is considerably higher than that of the non-silicone based defoaming agent used in the method of the present invention. Additionally, because no sillcone is present, there is no risk that- the distillates recovered from the delayed coking process will be contaminated with silicone which can cause downstream catalyst poisoning. While the non-silicone based defoaming agent described herein can be used with charge feeds having greater than 1/2% by weight sulphur, when the sulphur content is less than 1/2% by weight, it is necessary to use the novel silicone-containing composition of the preserlt invention. However~ even in this case, considerable advantage is realized as compared with conventional concentrated sili-cone defoamers. The silicone defoamer of the present invention, although containing much less silicone, produces the same foam control proper~ies as concentrated silicone products while minimizing the principal disadvantages involved 9~,~
with the use of such concentrated silicones. Specifically, since the silicone defoamers of the present invention contain only a small quantity of the organo siloxane polymer, there is less chance that silicone materials will migrate to the dis~illate fractions recovered from the coking drum.
Accordingly, there is less chance of downstream catalyst poisoning in the subsequent processing of the streams.
I'he invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are there-fore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalence of the claims are therefore intended to be embraced therein.
Claims (9)
1. A composition for use as an anti-foaming agent consisting essentially of from about 0.1 to about 20% by weight of a liquid organo-siloxane polymer having the general formula (R2SiO)n, wherein R is a lower alkyl radical, said polymer having a viscosity ranging from about 8000 to about 100,000 centistokes, and from about 20% to about 60% by weight of a C6-C12 range aliphatic alcohol, and from about 20% to about 60% by weight of a liquid organic carrier in which said siloxane polymer and said alcohol are soluble and which is generally inert to reaction in a delayed coking operation.
2. The composition of Claim 1 wherein said carrier comprises a polyol having the formula:
wherein R1 is hydrogen or a methyl group, R2 is hydrogen or a methyl group and the sum of x + y is from about 30 to about 45.
wherein R1 is hydrogen or a methyl group, R2 is hydrogen or a methyl group and the sum of x + y is from about 30 to about 45.
3. The composition of Claim 1 wherein said organo siloxane polymer comprises dimethyl polysiloxane.
4. The composition of Claim 1 wherein said alcohol com-prises 2-ethylhexanol.
5. The composition of Claim 2 wherein R1 and R2 are methyl groups.
6. In a delayed coking process wherein a heated feed stock is fed to a coking drum, the improvement comprising adding to said feed stock an effective amount of an anti-foaming composition as defined in claim 1.
7. The process of Claim 6 wherein the alcohol in the anti-foaming composition is 2-ethylhexanol.
8. The process of Claim 7 wherein the carrier in the anti-foaming composition comprises a polyol having the formula:
wherein R1 is hydrogen or a methyl group, R2 is hydrogen or a methyl group and the sum of x + y is from about 30 to about 45.
wherein R1 is hydrogen or a methyl group, R2 is hydrogen or a methyl group and the sum of x + y is from about 30 to about 45.
9. The process of Claim 8 wherein R1 and R2 are methyl groups.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US20157380A | 1980-10-28 | 1980-10-28 | |
| US201,573 | 1980-10-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1180975A true CA1180975A (en) | 1985-01-15 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000386825A Expired CA1180975A (en) | 1980-10-28 | 1981-09-28 | Composition and method for controlling foaming in delayed coking process |
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| Country | Link |
|---|---|
| JP (1) | JPS57102206A (en) |
| CA (1) | CA1180975A (en) |
| GB (1) | GB2088405B (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1296670C (en) * | 1988-04-15 | 1992-03-03 | Anil K. Jain | Use of antifoam to achieve high conversion in hydroconversion of heavy oils |
| WO2012117004A2 (en) * | 2011-03-01 | 2012-09-07 | Basf Se | Medium chain alkanols in additive concentrates for improving the reduction of foam in fuel oils |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55129116A (en) * | 1979-03-28 | 1980-10-06 | Adeka Argus Chem Co Ltd | Defoaming agent composition |
-
1981
- 1981-09-28 CA CA000386825A patent/CA1180975A/en not_active Expired
- 1981-10-27 JP JP17086481A patent/JPS57102206A/en active Pending
- 1981-10-27 GB GB8132395A patent/GB2088405B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB2088405A (en) | 1982-06-09 |
| JPS57102206A (en) | 1982-06-25 |
| GB2088405B (en) | 1984-07-18 |
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