CA1146597A - Crude oil cracking using partial combustion gases - Google Patents
Crude oil cracking using partial combustion gasesInfo
- Publication number
- CA1146597A CA1146597A CA000372906A CA372906A CA1146597A CA 1146597 A CA1146597 A CA 1146597A CA 000372906 A CA000372906 A CA 000372906A CA 372906 A CA372906 A CA 372906A CA 1146597 A CA1146597 A CA 1146597A
- Authority
- CA
- Canada
- Prior art keywords
- range
- steam
- fuel
- zone
- temperature
- 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
Landscapes
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
ABSTRACT
The cracking of crude oil or crude oil resi-dues is accomplished in an adiabatic reactor which fol-lows a partial combustion zone with the injection of superheated or shift steam into the combustion gases.
The advantages obtained are that the carbon monoxide produced by partial combustion is converted to carbon dioxide which is easily removed, there is no need to supply a separate source of fuel or hydrogen, and coke formation is substantially eliminated. The cracked oil produced in the process can be used as a quench oil and/or fuel to feed the partial combustion zone. The yields of olefins, especially ethylene, and aromatics is increased over processes using only superheated steam cracking.
18,442B-F -20-
The cracking of crude oil or crude oil resi-dues is accomplished in an adiabatic reactor which fol-lows a partial combustion zone with the injection of superheated or shift steam into the combustion gases.
The advantages obtained are that the carbon monoxide produced by partial combustion is converted to carbon dioxide which is easily removed, there is no need to supply a separate source of fuel or hydrogen, and coke formation is substantially eliminated. The cracked oil produced in the process can be used as a quench oil and/or fuel to feed the partial combustion zone. The yields of olefins, especially ethylene, and aromatics is increased over processes using only superheated steam cracking.
18,442B-F -20-
Description
CRUDE OIL CRACKING USING
P~RTIAL COMBUSTION GASES
This invention relates to a process for the cracking of crude oil using partial combustion gases wherein superheated steam, crude oil and oxygen are injected into a partial combustion zone at one or more points.
It is known in the prior art that crude oil and other hydrocarbon fractions may be thermally cracked by mixing superheated steam and the oil together and allow-ing the pyrolysis to proceed adiabatically. These pro-cesses allow crude and heavy hydrocarbon fractions, whichwould foul conventional tubes, to be cracked and have the advantage that the steam diluent and heat carrler may be readily condensed from the products and a savings is thereby made as only the product gases need to be com-pressed for separation. Among the disadvantages of theseprocesses are expense associated with the generation of the superheated steam in the 1699C to 2000C range gen-erally required. Also among the by-products formed in the cracking process are heavy aromatic liquids and coke which foul reactors and heat exchangers and which contain 18,442B-F -1- ~
. .
1~6S~7
P~RTIAL COMBUSTION GASES
This invention relates to a process for the cracking of crude oil using partial combustion gases wherein superheated steam, crude oil and oxygen are injected into a partial combustion zone at one or more points.
It is known in the prior art that crude oil and other hydrocarbon fractions may be thermally cracked by mixing superheated steam and the oil together and allow-ing the pyrolysis to proceed adiabatically. These pro-cesses allow crude and heavy hydrocarbon fractions, whichwould foul conventional tubes, to be cracked and have the advantage that the steam diluent and heat carrler may be readily condensed from the products and a savings is thereby made as only the product gases need to be com-pressed for separation. Among the disadvantages of theseprocesses are expense associated with the generation of the superheated steam in the 1699C to 2000C range gen-erally required. Also among the by-products formed in the cracking process are heavy aromatic liquids and coke which foul reactors and heat exchangers and which contain 18,442B-F -1- ~
. .
1~6S~7
-2-high quantities of sulfur and metals whlch must be dis-posed of. Some of the problems associated with the gen-eration of superheated steam have apparently been solved by using a hydrogen burner to generate high temperature gases, but the yields that may be obtained in this manner are still low and the by-products still remain a problem.
Other processes for pyrolysis of heavy hydro-carbons involve the use of a partial or complete combus-tion burner, where the crude oil or fraction thereof to be cracked is sprayed into the hot gases from the burner.
These processes avoid some of the problems associated with the generation of high temperature steam and (when partial combustion is used) also produce hydrogen gas which lowers the heat required for cracking, increases ethylene yield, and aromatics yield, and reduces coke formation.
The main disadvantage of these processes is that large ~uantities of non-condensible gases (especi-ally carbon monoxide) are produced, which must be com-pressed to be removed. This involves a considerable cost for large compressors and large size separation equipment.
In U.S. Patent 4,134,824, issued to Kamm et al., January 16, 1979, a process is disclosed in which crude oil is first distilled to separate asphaltic components. The distillate is then cracked using partial combustion gases from a methane burner to generate ethylene, with recycling of the asphaltic components to the burner. This process uses a high fuel to oxidant ratio, and does not generate H2 ln situ.
18,442B-F -2-~'' 11~6Cj97
Other processes for pyrolysis of heavy hydro-carbons involve the use of a partial or complete combus-tion burner, where the crude oil or fraction thereof to be cracked is sprayed into the hot gases from the burner.
These processes avoid some of the problems associated with the generation of high temperature steam and (when partial combustion is used) also produce hydrogen gas which lowers the heat required for cracking, increases ethylene yield, and aromatics yield, and reduces coke formation.
The main disadvantage of these processes is that large ~uantities of non-condensible gases (especi-ally carbon monoxide) are produced, which must be com-pressed to be removed. This involves a considerable cost for large compressors and large size separation equipment.
In U.S. Patent 4,134,824, issued to Kamm et al., January 16, 1979, a process is disclosed in which crude oil is first distilled to separate asphaltic components. The distillate is then cracked using partial combustion gases from a methane burner to generate ethylene, with recycling of the asphaltic components to the burner. This process uses a high fuel to oxidant ratio, and does not generate H2 ln situ.
18,442B-F -2-~'' 11~6Cj97
-3-It has been discovered that when a partial combustion burner is used to generate hydrogen, carbon monoxide, carbon dioxide, and water, and superheated or shift steam is injected into the burner or combustion gases, the superheated steam is additionally heated to a higher temperature and much of the CO produced in the burner is reacted with the steam by the shift reaction to produce greater quantities of CO2 and H2. This has the advantage that the benefits of hydrogen in the crack-ing process are realized while most of the CO, which isdifficult to remove, is converted to CO2 which can be readily scrubbed from the product gases with conventional acid gas absorbents such as caustic solutions of alkanol-amine solutions.
When crude oil or crude oil fractions are injected into this hydrogen-enriched gaseous mixture, the yield of the desired olefins and aromatics is increased over the use of superheated steam alone while the forma-tion of coke or coke deposits is virtually eliminated.
The use of this invention reduces the volume of off-gases to be processed as compared to the use of partial combus-tion cracking alone.
Additionally, it has been found that if the heavy oils which are generated in the processes are used as fuel for the partial combustion burner, any sulfur compounds contained therein are converted mainly to hydro-gen sulfide, and a smaller amount to carbonyl sulfide which may be scrubbed out using known techniques. This has the unique advantage that it allows a waste stream of residual oils, which may not be suitable for burning in 18,442B-F -3-~4~5~7
When crude oil or crude oil fractions are injected into this hydrogen-enriched gaseous mixture, the yield of the desired olefins and aromatics is increased over the use of superheated steam alone while the forma-tion of coke or coke deposits is virtually eliminated.
The use of this invention reduces the volume of off-gases to be processed as compared to the use of partial combus-tion cracking alone.
Additionally, it has been found that if the heavy oils which are generated in the processes are used as fuel for the partial combustion burner, any sulfur compounds contained therein are converted mainly to hydro-gen sulfide, and a smaller amount to carbonyl sulfide which may be scrubbed out using known techniques. This has the unique advantage that it allows a waste stream of residual oils, which may not be suitable for burning in 18,442B-F -3-~4~5~7
-4-air because of restrictions on sulfur emissions, to be used as some or all of the total fuel required to operate the process.
The present invention is a process for the cracking of crude oils or high boiling fractlons thereof to obtain a mixture of lower hydrocarbons with a high proportion of ethylene characterized by:
(l) partially burning a carbonaceous fuel with an oxidizing gas and process steam in a par-tial combustion zone to form a mixture of hot com-bustion gases having an average temperature in the range from 1200C to 2200C and containing more than 5 volume percent carbon monoxide;
(2) injecting superheated steam into said combustion gases in a shift reaction zone having an average temperature in the range from 1200C
to 1800C react with said carbon monoxide to form a gaseous mixture containing more than 5 volume percent hydrogen and carbon dioxide;
~3) injecting said crude oils or fractions thereof into said steam~hydrogen mixture in a crack-ing zone having an average temperature in the range of from 600C to 1500C under time and temperature conditions which crack the crude oils or fractions thereof into gaseous products and favor the forma-tion of ethylene; and (4) quenching the gaseous products with a hydrocarbon quench oil.
Another aspect of the invention is a method for the partial combustion cracking of crude oil or high boiling crude oil fractions whereby a heavy recycle oil 18,442B-F -4-~14~597 is recovered by quenching the gaseous products from the cracking step and this heavy recycle oil is recycled for use as a quench oil and/or use as a fuel or fuel supple-ment.
The present invention is illustrated by the drawing which is a schematic diagram showing the associ-ation of the reactor 10, the burner assembly 12, and the quench apparatus 14 together with the separation equip-ment 44.
In the drawing, a reactor assembly 10 is shown which has three zones comprising the partial combustion zone 11, a shift reaction zone 13 and a cracking zone 15, respectively. The reactor assembly is conventional and is illustrated by U.S. Patent 2,698,830, issued to Jenny, 15 January 4, 1955.
A burner 12 is fed with oxygen or oxygen--enriched air through conduit 18. A hydrocarbon fuel and steam are supplied to the burner through conduit 20 and a steam inlet conduit 22, respectively. The process or saturated steam used in conduit 22 preferably has a pressure of from about 50 to 250 pounds per square inch (3.53-17.7 kg/cm2) and a temperature of about 150C to 210C. This steam is used to mix and atomize the hydro-carbon feed in the burner 12.
Conduit 34 supplies superheated steam to the reactor 10 and/or the burner 12. This superheated steam generally has a pressure of from about 5 to 50 psig (0.35--3.53 kg/cmZ) and a temperature of about 700C to 1100C.
The superheated steam is supplied from a conventional 18,442B-F -5-~6S97 superheater (not shown). The flow of superheated steam is controlled by valves 26, 28, 30 and 32, associated with conduit 24.
Conduit 16 supplies crude oil or high boiling crude oil fractions, i.e., residuums to the cracking zone 15 in the reactor 10. The crude oil is stored in a sup-ply tank (now shown) and is heated by preheater (not shown) to a temperature of about 30C to 260C, depend-ing upon the crude oil, to a flowable viscosity for use.
Cracked hydrocarbons from the reactor 10 are then quenched with a quench oil in quench apparatus 14.
The quench apparatus can be of any well-known type, but a falling film quench apparatus is preferred. Hydrocar-bon gases are removed through conduit 38 and tars and heavy oils are removed through conduit 40 and fed to the burner 12 by a conduit (not shown).
outlet conduit 42 is provided to recycle quench oil back to the fuel conduit 20. The flow of the quench oil to the fuel conduit 20 is controlled and/or regulated by valve 43. Thus, if or when a surplus of quench oil is generated during the process, it can be used as fuel to make the process partially or wholly self-sustaining.
Hydrocarbon gases leave the quench apparatus 14 through conduit 38 and enter into the separation appa-ratus 44 which consists of conventional fractionators orcondensors, as shown in U.S. Patent 2,698,830, previously identified. The desired lower hydrocarbon gases such as ethylene and propylene, are removed by conduit 52.
18,442B-F -6-Light oils from the separation apparatus 44 are pumped by a pump (not shown) through conduit 47 where they diverge through conduits 36 and 48 to supply quench oil to the quench apparatus 14 and the fuel conduit 20, respectively. The flow of the light oils is controlled by valves 46 and 50. Valve 50 controls the flow back to the quench apparatus 14 and valve 46 controls the flow to the fuel conduit 20.
The temperature of the partial combustion zone is controlled so as to have an average temperature in the range from 1200C to 2200C and preferably from 1600C to 2000C. The average temperature in the shift reaction zone is in the range from 1200C to 1800C and preferably 1300C to 1600C. The average temperature in the cracking reaction zone is in the range from 600C to 1500C and preferably 700C to 1100C. The foregoing : average temperatures represent the estimated average tem-peratures of the top and the bottom of each of the respec-tive zones. Since there are no known temperature probes which can be inserted to directly read these temperatures, due to the high temperatures and high erosion, the same information can be restated by indicating the outlet tem-peratures which are measured on the outside of the respec-tive zones. Thus, for the partial combustion zone the outlet temperature is preferably at least 1700C. In the shift reaction zone the outlet temperature is preferably at least 1100C and the cracking reactor zone has a pre-ferred outlet temperature of at least 600C.
In the partial combustion zone, care should be exercised to insure that the average temperature is not lower than 1200C since the rate of combustion is too 18,442B-F -7-slow and inefficient, which results in more carbon and methane formation. Further, the upper limit should not be exceeded since the high temperatures will damage the refractory linings of the reactor.
In the shift reaction zone, the average tem-perature should be kept above 1200C since below that tem-perature there is no significant shift reaction rate, i.e., conversion of CO and H2O to ~2 and CO2. The upper temper-ature range is limited by the fact that it represents the highest temperature that is known to be obtained under the conditions of this invention.
In the cracking zone, the average temperature should be kept above 600C since there is no significant cracking below this temperature. Above 1500C it has been found that very short residence times are required and that more acetylene and less ethylene are produced.
The hot combustion gases resulting from the partial combustion contain more than 5 volume percent C0 and preferably in the range of 6 to 60 volume percent.
The gaseous shift mixture contains more than
The present invention is a process for the cracking of crude oils or high boiling fractlons thereof to obtain a mixture of lower hydrocarbons with a high proportion of ethylene characterized by:
(l) partially burning a carbonaceous fuel with an oxidizing gas and process steam in a par-tial combustion zone to form a mixture of hot com-bustion gases having an average temperature in the range from 1200C to 2200C and containing more than 5 volume percent carbon monoxide;
(2) injecting superheated steam into said combustion gases in a shift reaction zone having an average temperature in the range from 1200C
to 1800C react with said carbon monoxide to form a gaseous mixture containing more than 5 volume percent hydrogen and carbon dioxide;
~3) injecting said crude oils or fractions thereof into said steam~hydrogen mixture in a crack-ing zone having an average temperature in the range of from 600C to 1500C under time and temperature conditions which crack the crude oils or fractions thereof into gaseous products and favor the forma-tion of ethylene; and (4) quenching the gaseous products with a hydrocarbon quench oil.
Another aspect of the invention is a method for the partial combustion cracking of crude oil or high boiling crude oil fractions whereby a heavy recycle oil 18,442B-F -4-~14~597 is recovered by quenching the gaseous products from the cracking step and this heavy recycle oil is recycled for use as a quench oil and/or use as a fuel or fuel supple-ment.
The present invention is illustrated by the drawing which is a schematic diagram showing the associ-ation of the reactor 10, the burner assembly 12, and the quench apparatus 14 together with the separation equip-ment 44.
In the drawing, a reactor assembly 10 is shown which has three zones comprising the partial combustion zone 11, a shift reaction zone 13 and a cracking zone 15, respectively. The reactor assembly is conventional and is illustrated by U.S. Patent 2,698,830, issued to Jenny, 15 January 4, 1955.
A burner 12 is fed with oxygen or oxygen--enriched air through conduit 18. A hydrocarbon fuel and steam are supplied to the burner through conduit 20 and a steam inlet conduit 22, respectively. The process or saturated steam used in conduit 22 preferably has a pressure of from about 50 to 250 pounds per square inch (3.53-17.7 kg/cm2) and a temperature of about 150C to 210C. This steam is used to mix and atomize the hydro-carbon feed in the burner 12.
Conduit 34 supplies superheated steam to the reactor 10 and/or the burner 12. This superheated steam generally has a pressure of from about 5 to 50 psig (0.35--3.53 kg/cmZ) and a temperature of about 700C to 1100C.
The superheated steam is supplied from a conventional 18,442B-F -5-~6S97 superheater (not shown). The flow of superheated steam is controlled by valves 26, 28, 30 and 32, associated with conduit 24.
Conduit 16 supplies crude oil or high boiling crude oil fractions, i.e., residuums to the cracking zone 15 in the reactor 10. The crude oil is stored in a sup-ply tank (now shown) and is heated by preheater (not shown) to a temperature of about 30C to 260C, depend-ing upon the crude oil, to a flowable viscosity for use.
Cracked hydrocarbons from the reactor 10 are then quenched with a quench oil in quench apparatus 14.
The quench apparatus can be of any well-known type, but a falling film quench apparatus is preferred. Hydrocar-bon gases are removed through conduit 38 and tars and heavy oils are removed through conduit 40 and fed to the burner 12 by a conduit (not shown).
outlet conduit 42 is provided to recycle quench oil back to the fuel conduit 20. The flow of the quench oil to the fuel conduit 20 is controlled and/or regulated by valve 43. Thus, if or when a surplus of quench oil is generated during the process, it can be used as fuel to make the process partially or wholly self-sustaining.
Hydrocarbon gases leave the quench apparatus 14 through conduit 38 and enter into the separation appa-ratus 44 which consists of conventional fractionators orcondensors, as shown in U.S. Patent 2,698,830, previously identified. The desired lower hydrocarbon gases such as ethylene and propylene, are removed by conduit 52.
18,442B-F -6-Light oils from the separation apparatus 44 are pumped by a pump (not shown) through conduit 47 where they diverge through conduits 36 and 48 to supply quench oil to the quench apparatus 14 and the fuel conduit 20, respectively. The flow of the light oils is controlled by valves 46 and 50. Valve 50 controls the flow back to the quench apparatus 14 and valve 46 controls the flow to the fuel conduit 20.
The temperature of the partial combustion zone is controlled so as to have an average temperature in the range from 1200C to 2200C and preferably from 1600C to 2000C. The average temperature in the shift reaction zone is in the range from 1200C to 1800C and preferably 1300C to 1600C. The average temperature in the cracking reaction zone is in the range from 600C to 1500C and preferably 700C to 1100C. The foregoing : average temperatures represent the estimated average tem-peratures of the top and the bottom of each of the respec-tive zones. Since there are no known temperature probes which can be inserted to directly read these temperatures, due to the high temperatures and high erosion, the same information can be restated by indicating the outlet tem-peratures which are measured on the outside of the respec-tive zones. Thus, for the partial combustion zone the outlet temperature is preferably at least 1700C. In the shift reaction zone the outlet temperature is preferably at least 1100C and the cracking reactor zone has a pre-ferred outlet temperature of at least 600C.
In the partial combustion zone, care should be exercised to insure that the average temperature is not lower than 1200C since the rate of combustion is too 18,442B-F -7-slow and inefficient, which results in more carbon and methane formation. Further, the upper limit should not be exceeded since the high temperatures will damage the refractory linings of the reactor.
In the shift reaction zone, the average tem-perature should be kept above 1200C since below that tem-perature there is no significant shift reaction rate, i.e., conversion of CO and H2O to ~2 and CO2. The upper temper-ature range is limited by the fact that it represents the highest temperature that is known to be obtained under the conditions of this invention.
In the cracking zone, the average temperature should be kept above 600C since there is no significant cracking below this temperature. Above 1500C it has been found that very short residence times are required and that more acetylene and less ethylene are produced.
The hot combustion gases resulting from the partial combustion contain more than 5 volume percent C0 and preferably in the range of 6 to 60 volume percent.
The gaseous shift mixture contains more than
5 volume percent H2 and preferably in the range of 6 to 70 volume percent.
The actual composition of these combustion gases can vary considerably depending upon (1) the type of fuel being used, (2) the relative amount of oxidizer to fuel, and (3) the amount of moderating steam used to protect the refractory lining of the reactor. This flex-ibility of composition allows the maximum or optimum con-ditions for each case to be developed on an individual 18,442B-F -8-g basis. For instance, if a heavy oil or residue is being crac~ed there will probably be enough excess (quench oil) heavy cracked oil produced to operate the burner, thus usually a considerable quantity of CO would be present in the burner gas. But, if a relatively low molecular weight paraffinic feedstock is being cracked, not enough heavy cracked oil may be produced to sustain the burner, so that some of the light gas (H2+CH4) produced from the pyrolysis is used in the burner, which results in more hydrogen and less C0 being present.
For the invention to function it is only necessary that the minlmum conditions be met, and the preferred range or values will vary depending upon the factors listed above.
The weight ratio of oxygen to fuel used in the burner in the process of this invention for partial combustion is greater than about 1.2:1. The upper limit should not exceed about 2.9:1. This upper limit will vary somewhat depending upon the carbon-hydrogen ratio of the fuel.
The weight ratio of process steam to fuel is normally in the range from about 0.5:1 to 10:1. The use of this ratio is not critical since the process steam is used primarily to control the temperature in the combus-tion zone, and the above ratios are dependent upon thequantity of oxygen used.
The weight ratio of superheated steam used to burner fuel is in the range from about 2.0:1 to 8.0:1. It -has been found that the use of a ratio below this weight 18,442B-F -9-65~7 ratio results in a poor shift reaction since too little superheated steam ls present, whereas the use of a ratio above this weight ratio will cool the cracking reaction and slow down the desired shift reaction.
The crude oil or fractions thereof is sprayed or injected into the cracking zone at a ratio from about 0.5 to 8.0 parts by weight of oil per part by weight of fuel and preferably 1.5 to 6.0 parts by weight of oil per part by weight of fuel to give a residence time from about 10 0.01 to l.0 seconds in the reactor and preferably 0.05 to 0.5 seconds.
The oxidizing gas used in the partial combus-tion zone can be pure oxygen, or air enriched with oxygen.
The fuel which is burned in the partial com-bustion zone can be any one of the known fuel oils, cracked oils, or a mixture of fuel oils and cracked oils, natural gas, or cracked gases.
The pressure range for the reactor during combustion is in the range from 0-200 psig (0-14.1 kg/cm2) 20 and preferably in the range from 5-65 psig (0.35-4.59 kg/cm2 ) .
The invention is illustrated by the following examples:
Example 1 Using the apparatus disclosed in the drawing and the process of the present invention, the following reactants were processed under the given conditions:
18,442B-F -10-Fuel:
30 API Domestic Crude 100 lb/hr (45.3 kg/hr) Oxidant:
Oxygen 184 lb/hr (83.5 kg/hr) 5 Process steam (200C) to burner: 180 lb/hr (81.6 kg/hr) Shift steam: 549 lb/hr (248 kg/hr) Cracking stock:
30 API Domestic CrudP 223 lb/hr (101 kg/hr) Conditions:
Reactor Pressure 11.1 psig (0.78 kg/cm2) Temperature Partial Combustion Zone 1910C
Shift Steam Inlet Temp. 905C
Shift Steam Inlet Into top of Shift Zone Temperature of Shift Zone Outlet 1210C
Temperature of Cracking Reactor Outlet 696C
Reactor Volume 1.64 ft3 (46.4 1) Residence Time 0.15 seconds The following yields in pounds (kg) were obtained per 100 pounds (45.3 kg) of cracking stock.
18,442B-F -11-~65~7 H23.1 (1.4) C3H41.1 (0.50) C05.7 (2.58) C3H68.8 (3.98) CH414.1 (6.40) C4 5.0 (2.27) C23 0 (1.36) c5 3.8 (1.72) 5 H2S0.2 (0.09) Benzene8.3 (3.76) C2H21.9 (0.86) Toluene4.5 (2.04) C2H424.8 (11.3) c6+*20.5 (9.31) C2H61.6 (0.73) *C + includes all carbon compounds of C6 or greater e~cept benzene and toluene.
Example 2 Using the same apparatus as in Example 1 and the process of the present invention, the following reac-tants were reacted in a continuous manner:
18,442B-F -12-~1~6S~37 Based on 100 lb (45.3 kg/hr) fuel/hr Fuel:
~eavy recycle oil or quench oil from Example 1 100 lb/hr (45.3 kg/hr) Oxidant:
Oxygen 188 lb/hr (85.3 kg/hr) 10 Process steam (200C) to burner: 240 lb/hr (108 kg/hr) shift steam: 311 lb/hr (141 kg/hr) Cracking stock:
30 API Domestic Crude 220 lb/hr (99.8 kg/hr) 15 Conditions:
Reactor Pressure 6.1 psig (0.42 kg/cm2) Temperature Partial Combustion Zone 1903C
Shift Steam Inlet Temp. 870C
Shift Steam Inlet Into top of Shift Zone Temperature of Shift Zone Outlet 1163C
Temperature of Cracking Reactor Outlet 697C
Reactor Volume 1.64 ft3 (46.4 1) Residence Time 0.21 seconds The following yields in pounds (kg) were obtained per 100 pounds (45.3 kg) of cracking stock.
18,442B-F -13-1~46597 H21.3 (0 59) C3H40 9 (0.41) CO3.9 (1.76) C3H67.3 (3.31) CH411.3 (5.12~ c46.2 (2.81) C25.2 (2.36) c51.9 (0.86) 5 H2S0.2 (0.09) Benzene7.2 (3.26) C2H22.5 (1.13) Toluene5.2 (2.36) C2H420.7 (9.38) c6+*25.0 (11.3) C2H61.4 (0.64) *C6+ includes all carbon compounds of C6 or greater except benzene and toluene.
Control - Total Combustion with Superheated Steam 49 Pounds (22 kg) of fuel oil were burned per hour with 145 pounds (65.8 kg~ of oxygen per hour which resulted in essentially complete combustion of the fuel 15 oil to CO2 and H2O. Additionally, 306 pounds (139 kg) of 200C process steam was added to the burner to maintain the temperature below 1900C. The resulting gaseous mix-ture was combined with 300 pounds (136 kg) of steam per hour which had been superheated to 870C to yield a gas-eous heat carrier containing in volume percentages 0.6 H2;
0.3 CO; 8.9 CO2; and 90.2 H2O at a temperature of 1460C.
Into this gaseous heat carrier, 158 pounds (71.8 kg) per hour of vacuum gas oil (650F-1050F (343C--566C) boiling range) was sprayed using 75 pounds (34.0 kg) of 200C process steam per hour for atomization. The yield of products are shown in Table I.
18,442B-F -14-Exam~le 3 82 Pounds (37.2 kg) per hour of fuel oll were burned with 163 pounds (74.0 kg) of oxygen per hour. Addi-tionally, 255 pounds (116 kg) per hour of 200C process steam was added to maintain the flame temperature below 1900C. This mixture was deficient in oxygen and resulted in the partial combustion of the fuel. The gaseous mix-ture contained substantial portions of C0 and H2 in addi-tion to CO2 and H20. The volume percentages in the gas-10 eous mixture were 12.5 H2; 12.5 C0; 11.2 C02; and 63.4 H20 .
The resulting gaseous mixture was combinedwith 300 pounds (136 kg) per hour of steam which had been superheated to 870C. At these conditions with a residence time sufficient to achieve e~uilibrium, 30 percent of the C0 present was converted to C02 with a corresponding increase in ~2 content.
The resulting gaseous heat carrier had a tem-perature of 1460C and consisted of (volume percentages) 20 9.8 H2; 5.3 CO; 8.9 CO2; and 75.9 H2O.
Into this gaseous heat carrier 158 pounds (71.8 kg) per hour of vacuum gas oil was sprayed using 75 pounds (34.0 kg) per hour of process steam (200C).
The yields of products are shown in Table I. It is to be noted that the yield of ethylene is increased about 28 percent over the control and thus the injection of superheated steam into the partial combustion gases is highly effective to lncrease the yield of ethylene.
A detailed comparison of Example 3 and the control is shown in Table II.
18,442B-F -15-TABLE I
Yields in pounds (kg) per 100 pounds (45.3 kg) of feedstock Control Example 3 ~2 1.7 (0.77) 1.0 (0.45) CO S.0 ~2.27) 3.0 (1.36) CH4 10.3 (4.68) 13.7 (6.20) C2 0.2 (0.09) 2.4 (1.09) H2S 0.7 (0.32) 1.1 (0.50) 10 C2H2 2.7 (1.22) 2.7 (1.22) C2H420.9 (9.48) 26.8 (12.2) C2H6 1.0 (0.45) 1.1 (0.50) C3H4 0.8 (0.36) 0.9 (0.41) C3H6 4.3 (1.95) 5.8 (2.63) 15 C4 3.0 (1.36) 4.0 (1.82) C5 1.2 (0.54) 1.3 (0.59) Benzene7.5 (3.40) 8.0 (3.62) Toluene4.7 (2.13) 3.0 (1.36) c6+ 39.6 (17.5) 29.3 (13-3 18,442B-F -16-TABLE II
Control Example 3 Fuel, lb/hr (kg) 49 (22.0) 82 (37.2) Oxygen, lb/hr (kg) 145 (65.8) 163 (74.0) 200C Steam, lb/hr (kg/hr) 306 (139.0) 255 (116.0) Combustion Temp. C1900 1900 870C Steam, lb/hr (kg/hr) 300 (136.0) 300 (136.0) Total lb Carrier Gas (kg)800 (362.0) 800 (362.0) Temp. of Carrier Gas, C 1460 1460 Feedstock, lb/hr (kg)158 (71.8)158 (71.8) Products, lb~hr~ kg) H 2.7 (1.22) 9.6 (4.35) C~ 8.7 (3.94) 44.4 (22.0) 20 CO161.2 (73.0) 181.0 (82.2) CH216.3 (7.39) 21.7 (9.84) C2~24.2 (1.90) 4.1 (1.86) C H33.0 (15.0) 42.3 (19.2) c2H41.5 (0.68) 1.8 (0.81) 25 C3H41.3 (0.59) 1.4 (0.63) C H6.8 (3.08) 9.1 (4.11) c3+683.1 (37.6) 73.8 (33.4) H40638.1 (289) 567.0 (257) H2S1.1 (0.50) 1.7 (0.77) 18,442B-F -17-
The actual composition of these combustion gases can vary considerably depending upon (1) the type of fuel being used, (2) the relative amount of oxidizer to fuel, and (3) the amount of moderating steam used to protect the refractory lining of the reactor. This flex-ibility of composition allows the maximum or optimum con-ditions for each case to be developed on an individual 18,442B-F -8-g basis. For instance, if a heavy oil or residue is being crac~ed there will probably be enough excess (quench oil) heavy cracked oil produced to operate the burner, thus usually a considerable quantity of CO would be present in the burner gas. But, if a relatively low molecular weight paraffinic feedstock is being cracked, not enough heavy cracked oil may be produced to sustain the burner, so that some of the light gas (H2+CH4) produced from the pyrolysis is used in the burner, which results in more hydrogen and less C0 being present.
For the invention to function it is only necessary that the minlmum conditions be met, and the preferred range or values will vary depending upon the factors listed above.
The weight ratio of oxygen to fuel used in the burner in the process of this invention for partial combustion is greater than about 1.2:1. The upper limit should not exceed about 2.9:1. This upper limit will vary somewhat depending upon the carbon-hydrogen ratio of the fuel.
The weight ratio of process steam to fuel is normally in the range from about 0.5:1 to 10:1. The use of this ratio is not critical since the process steam is used primarily to control the temperature in the combus-tion zone, and the above ratios are dependent upon thequantity of oxygen used.
The weight ratio of superheated steam used to burner fuel is in the range from about 2.0:1 to 8.0:1. It -has been found that the use of a ratio below this weight 18,442B-F -9-65~7 ratio results in a poor shift reaction since too little superheated steam ls present, whereas the use of a ratio above this weight ratio will cool the cracking reaction and slow down the desired shift reaction.
The crude oil or fractions thereof is sprayed or injected into the cracking zone at a ratio from about 0.5 to 8.0 parts by weight of oil per part by weight of fuel and preferably 1.5 to 6.0 parts by weight of oil per part by weight of fuel to give a residence time from about 10 0.01 to l.0 seconds in the reactor and preferably 0.05 to 0.5 seconds.
The oxidizing gas used in the partial combus-tion zone can be pure oxygen, or air enriched with oxygen.
The fuel which is burned in the partial com-bustion zone can be any one of the known fuel oils, cracked oils, or a mixture of fuel oils and cracked oils, natural gas, or cracked gases.
The pressure range for the reactor during combustion is in the range from 0-200 psig (0-14.1 kg/cm2) 20 and preferably in the range from 5-65 psig (0.35-4.59 kg/cm2 ) .
The invention is illustrated by the following examples:
Example 1 Using the apparatus disclosed in the drawing and the process of the present invention, the following reactants were processed under the given conditions:
18,442B-F -10-Fuel:
30 API Domestic Crude 100 lb/hr (45.3 kg/hr) Oxidant:
Oxygen 184 lb/hr (83.5 kg/hr) 5 Process steam (200C) to burner: 180 lb/hr (81.6 kg/hr) Shift steam: 549 lb/hr (248 kg/hr) Cracking stock:
30 API Domestic CrudP 223 lb/hr (101 kg/hr) Conditions:
Reactor Pressure 11.1 psig (0.78 kg/cm2) Temperature Partial Combustion Zone 1910C
Shift Steam Inlet Temp. 905C
Shift Steam Inlet Into top of Shift Zone Temperature of Shift Zone Outlet 1210C
Temperature of Cracking Reactor Outlet 696C
Reactor Volume 1.64 ft3 (46.4 1) Residence Time 0.15 seconds The following yields in pounds (kg) were obtained per 100 pounds (45.3 kg) of cracking stock.
18,442B-F -11-~65~7 H23.1 (1.4) C3H41.1 (0.50) C05.7 (2.58) C3H68.8 (3.98) CH414.1 (6.40) C4 5.0 (2.27) C23 0 (1.36) c5 3.8 (1.72) 5 H2S0.2 (0.09) Benzene8.3 (3.76) C2H21.9 (0.86) Toluene4.5 (2.04) C2H424.8 (11.3) c6+*20.5 (9.31) C2H61.6 (0.73) *C + includes all carbon compounds of C6 or greater e~cept benzene and toluene.
Example 2 Using the same apparatus as in Example 1 and the process of the present invention, the following reac-tants were reacted in a continuous manner:
18,442B-F -12-~1~6S~37 Based on 100 lb (45.3 kg/hr) fuel/hr Fuel:
~eavy recycle oil or quench oil from Example 1 100 lb/hr (45.3 kg/hr) Oxidant:
Oxygen 188 lb/hr (85.3 kg/hr) 10 Process steam (200C) to burner: 240 lb/hr (108 kg/hr) shift steam: 311 lb/hr (141 kg/hr) Cracking stock:
30 API Domestic Crude 220 lb/hr (99.8 kg/hr) 15 Conditions:
Reactor Pressure 6.1 psig (0.42 kg/cm2) Temperature Partial Combustion Zone 1903C
Shift Steam Inlet Temp. 870C
Shift Steam Inlet Into top of Shift Zone Temperature of Shift Zone Outlet 1163C
Temperature of Cracking Reactor Outlet 697C
Reactor Volume 1.64 ft3 (46.4 1) Residence Time 0.21 seconds The following yields in pounds (kg) were obtained per 100 pounds (45.3 kg) of cracking stock.
18,442B-F -13-1~46597 H21.3 (0 59) C3H40 9 (0.41) CO3.9 (1.76) C3H67.3 (3.31) CH411.3 (5.12~ c46.2 (2.81) C25.2 (2.36) c51.9 (0.86) 5 H2S0.2 (0.09) Benzene7.2 (3.26) C2H22.5 (1.13) Toluene5.2 (2.36) C2H420.7 (9.38) c6+*25.0 (11.3) C2H61.4 (0.64) *C6+ includes all carbon compounds of C6 or greater except benzene and toluene.
Control - Total Combustion with Superheated Steam 49 Pounds (22 kg) of fuel oil were burned per hour with 145 pounds (65.8 kg~ of oxygen per hour which resulted in essentially complete combustion of the fuel 15 oil to CO2 and H2O. Additionally, 306 pounds (139 kg) of 200C process steam was added to the burner to maintain the temperature below 1900C. The resulting gaseous mix-ture was combined with 300 pounds (136 kg) of steam per hour which had been superheated to 870C to yield a gas-eous heat carrier containing in volume percentages 0.6 H2;
0.3 CO; 8.9 CO2; and 90.2 H2O at a temperature of 1460C.
Into this gaseous heat carrier, 158 pounds (71.8 kg) per hour of vacuum gas oil (650F-1050F (343C--566C) boiling range) was sprayed using 75 pounds (34.0 kg) of 200C process steam per hour for atomization. The yield of products are shown in Table I.
18,442B-F -14-Exam~le 3 82 Pounds (37.2 kg) per hour of fuel oll were burned with 163 pounds (74.0 kg) of oxygen per hour. Addi-tionally, 255 pounds (116 kg) per hour of 200C process steam was added to maintain the flame temperature below 1900C. This mixture was deficient in oxygen and resulted in the partial combustion of the fuel. The gaseous mix-ture contained substantial portions of C0 and H2 in addi-tion to CO2 and H20. The volume percentages in the gas-10 eous mixture were 12.5 H2; 12.5 C0; 11.2 C02; and 63.4 H20 .
The resulting gaseous mixture was combinedwith 300 pounds (136 kg) per hour of steam which had been superheated to 870C. At these conditions with a residence time sufficient to achieve e~uilibrium, 30 percent of the C0 present was converted to C02 with a corresponding increase in ~2 content.
The resulting gaseous heat carrier had a tem-perature of 1460C and consisted of (volume percentages) 20 9.8 H2; 5.3 CO; 8.9 CO2; and 75.9 H2O.
Into this gaseous heat carrier 158 pounds (71.8 kg) per hour of vacuum gas oil was sprayed using 75 pounds (34.0 kg) per hour of process steam (200C).
The yields of products are shown in Table I. It is to be noted that the yield of ethylene is increased about 28 percent over the control and thus the injection of superheated steam into the partial combustion gases is highly effective to lncrease the yield of ethylene.
A detailed comparison of Example 3 and the control is shown in Table II.
18,442B-F -15-TABLE I
Yields in pounds (kg) per 100 pounds (45.3 kg) of feedstock Control Example 3 ~2 1.7 (0.77) 1.0 (0.45) CO S.0 ~2.27) 3.0 (1.36) CH4 10.3 (4.68) 13.7 (6.20) C2 0.2 (0.09) 2.4 (1.09) H2S 0.7 (0.32) 1.1 (0.50) 10 C2H2 2.7 (1.22) 2.7 (1.22) C2H420.9 (9.48) 26.8 (12.2) C2H6 1.0 (0.45) 1.1 (0.50) C3H4 0.8 (0.36) 0.9 (0.41) C3H6 4.3 (1.95) 5.8 (2.63) 15 C4 3.0 (1.36) 4.0 (1.82) C5 1.2 (0.54) 1.3 (0.59) Benzene7.5 (3.40) 8.0 (3.62) Toluene4.7 (2.13) 3.0 (1.36) c6+ 39.6 (17.5) 29.3 (13-3 18,442B-F -16-TABLE II
Control Example 3 Fuel, lb/hr (kg) 49 (22.0) 82 (37.2) Oxygen, lb/hr (kg) 145 (65.8) 163 (74.0) 200C Steam, lb/hr (kg/hr) 306 (139.0) 255 (116.0) Combustion Temp. C1900 1900 870C Steam, lb/hr (kg/hr) 300 (136.0) 300 (136.0) Total lb Carrier Gas (kg)800 (362.0) 800 (362.0) Temp. of Carrier Gas, C 1460 1460 Feedstock, lb/hr (kg)158 (71.8)158 (71.8) Products, lb~hr~ kg) H 2.7 (1.22) 9.6 (4.35) C~ 8.7 (3.94) 44.4 (22.0) 20 CO161.2 (73.0) 181.0 (82.2) CH216.3 (7.39) 21.7 (9.84) C2~24.2 (1.90) 4.1 (1.86) C H33.0 (15.0) 42.3 (19.2) c2H41.5 (0.68) 1.8 (0.81) 25 C3H41.3 (0.59) 1.4 (0.63) C H6.8 (3.08) 9.1 (4.11) c3+683.1 (37.6) 73.8 (33.4) H40638.1 (289) 567.0 (257) H2S1.1 (0.50) 1.7 (0.77) 18,442B-F -17-
Claims (7)
1. A process for the cracking of crude oils or high boiling fractions thereof to obtain a mixture of lower hydrocarbons with a high proportion of ethylene characterized by:
(1) partially burning a carbonaceous fuel with an oxidizing gas and process steam in a par-tial combustion zone to form a mixture of hot com-bustion gases having an average temperature in the range from 1200°C to 2200°C and containing more than 5 volume percent carbon monoxide;
(2) injecting superheated steam into said combustion gases in a shift reaction zone having an average temperature in the range from 1200°C
to 1800°C react with said carbon monoxide to form a gaseous mixture containing more than 5 volume percent hydrogen and carbon dioxide;
(3) injecting said crude oils or fractions thereof into said steam-hydrogen mixture in a crack-ing zone having an average temperature in the range of from 600°C to 1500°C under time and temperature conditions which crack the crude oils or fractions thereof into gaseous products and favor the forma-tion of ethylene; and (4) quenching the gaseous products with a hydrocarbon quench oil.
18,442B-F -18-
(1) partially burning a carbonaceous fuel with an oxidizing gas and process steam in a par-tial combustion zone to form a mixture of hot com-bustion gases having an average temperature in the range from 1200°C to 2200°C and containing more than 5 volume percent carbon monoxide;
(2) injecting superheated steam into said combustion gases in a shift reaction zone having an average temperature in the range from 1200°C
to 1800°C react with said carbon monoxide to form a gaseous mixture containing more than 5 volume percent hydrogen and carbon dioxide;
(3) injecting said crude oils or fractions thereof into said steam-hydrogen mixture in a crack-ing zone having an average temperature in the range of from 600°C to 1500°C under time and temperature conditions which crack the crude oils or fractions thereof into gaseous products and favor the forma-tion of ethylene; and (4) quenching the gaseous products with a hydrocarbon quench oil.
18,442B-F -18-
2. The process as set forth in Claim 1 wherein the gas formed by said partial combustion has an average temperature in the range of 1300°C to 1600°C.
3. The process as set forth in Claim 1 wherein the weight ratio of superheated steam to fuel is in the range of 2:1 to 8:1.
4. The process as set forth in Claim 1 wherein the crude oils or fractions thereof are cracked at a temperature in the range from 700°C to 1100°C and have a residence time of 0.01 to 1.0 second.
5. The process as set forth in Claim 1 wherein said superheated steam has a temperature in the range of 700°C to 1100°C.
6. The process of Claim 1 wherein said carbonaceous fuel is a hydrocarbon oil.
7. The process of Claim 1 wherein a por-tion of said quench oil is recycled to the quench zone and a second portion is recycled to said combustion zone and is blended with said hydrocarbon oil.
18,442B-F -19-
18,442B-F -19-
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000372906A CA1146597A (en) | 1981-03-12 | 1981-03-12 | Crude oil cracking using partial combustion gases |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000372906A CA1146597A (en) | 1981-03-12 | 1981-03-12 | Crude oil cracking using partial combustion gases |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1146597A true CA1146597A (en) | 1983-05-17 |
Family
ID=4119439
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000372906A Expired CA1146597A (en) | 1981-03-12 | 1981-03-12 | Crude oil cracking using partial combustion gases |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1146597A (en) |
-
1981
- 1981-03-12 CA CA000372906A patent/CA1146597A/en not_active Expired
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4264435A (en) | Crude oil cracking using partial combustion gases | |
| CA1219005A (en) | Thermal cracking process for selectively producing olefins and aromatic hydrocarbons from hydrocarbons | |
| EP0130932B1 (en) | Thermal cracking process for selectively producing petrochemical products from hydrocarbons | |
| US4599479A (en) | Thermal cracking process for producing olefins from hydrocarbons | |
| CA1218957A (en) | Process for the production of acetylene and synthesis or reduction gas from coal in an electric arc process | |
| JPS60219292A (en) | Selective production of petrochemicals | |
| US3252774A (en) | Production of hydrogen-containing gases | |
| CA1110191A (en) | Processing of tar sands | |
| US4134740A (en) | Method for energy utilization in producing synthesis gas and recovering unconverted carbon | |
| CA1227500A (en) | Production of acetylene from coal | |
| JPH0244355B2 (en) | ||
| EP0059772B1 (en) | Crude oil cracking using partial combustion gases | |
| JPH0323590B2 (en) | ||
| CA1146597A (en) | Crude oil cracking using partial combustion gases | |
| US2977299A (en) | Production of chemical products from coal products | |
| US4402709A (en) | Simultaneous production of clean dewatered and clean saturated streams of synthesis gas | |
| US2698782A (en) | Preparation of motor gasoline from carbonaceous feed material | |
| CA1212968A (en) | Thermal cracking process for producing olefins and synthetic gas from hydrocarbons | |
| US3980451A (en) | Gasification process | |
| US4840723A (en) | Hydrocarbons pyrolysis | |
| CA1044894A (en) | Substitute fuel gas generation | |
| US4411671A (en) | Production of synthesis gas from heavy hydrocarbon fuels containing high metal concentrations | |
| CA1038627A (en) | Gasification process | |
| KR840000577B1 (en) | Crude oil crackung using partial combustion gases | |
| CA1204285A (en) | Production of synthesis gas from heavy hydrocarbon fuels containing high metal concentrations |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |