CA1047543A - Process for cracking crude oil - Google Patents
Process for cracking crude oilInfo
- Publication number
- CA1047543A CA1047543A CA242,995A CA242995A CA1047543A CA 1047543 A CA1047543 A CA 1047543A CA 242995 A CA242995 A CA 242995A CA 1047543 A CA1047543 A CA 1047543A
- Authority
- CA
- Canada
- Prior art keywords
- zone
- crude oil
- psig
- mixing
- gases
- 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
-
- 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
- C10G2400/00—Products obtained by processes covered by groups C10G9/00 - C10G69/14
- C10G2400/20—C2-C4 olefins
Landscapes
- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A process for the cracking of crude oil to provide lower olefins, said process being carried out in a system comprising a mixing zone and an adiabatic reaction zone, each of said zones having an upstream end and a downstream end, the downstream end of the mixing zone being contiguous with the upstream end of the reaction zone, wherein both of said zones are in open relationship with each other and have a common geometrical axis running from the upstream end of the mixing ??e through the downstream end of the reaction zone, and a quenching zone, comprising the following steps:
(a) introducing into the mixing zone in a direction about perpendicular to the axis, a mixture of combustion gases,produced from the essentially complete combustion of a fuel gas and oxygen mixed together with steam, at subsonic velocity ant an inlet temperature of about 1000°C. to about 2400°C.;
(b) introducing into the mixing zone in a downstream axial direction, crude oil, in a ratio of about 0.5 to about 1 part by weight of crude oil per part by weight of gases, in such a manner that essentially all of the crude oil vaporizes into the gases in said mixing zone;
(c) passing the effluent from the mixing zone into the reaction zone wherein the outlet temperature of the reaction zone is in the range of about 600°C. to about 1100°C., the pressure of the reaction zone is in the range of about 3 psig to about 30 psig, and the residence time of the crude oil and products thereof in the mixing zone and the reaction zone combined in about 6 to about 60 milliseconds;
(d) passing the effluent from the reaction zone into the quenching zone, said quenching having a sufficiently low temperature to stop the reaction essentially instant-aneously; and (e) recovering the effluent from the quenching zone.
A process for the cracking of crude oil to provide lower olefins, said process being carried out in a system comprising a mixing zone and an adiabatic reaction zone, each of said zones having an upstream end and a downstream end, the downstream end of the mixing zone being contiguous with the upstream end of the reaction zone, wherein both of said zones are in open relationship with each other and have a common geometrical axis running from the upstream end of the mixing ??e through the downstream end of the reaction zone, and a quenching zone, comprising the following steps:
(a) introducing into the mixing zone in a direction about perpendicular to the axis, a mixture of combustion gases,produced from the essentially complete combustion of a fuel gas and oxygen mixed together with steam, at subsonic velocity ant an inlet temperature of about 1000°C. to about 2400°C.;
(b) introducing into the mixing zone in a downstream axial direction, crude oil, in a ratio of about 0.5 to about 1 part by weight of crude oil per part by weight of gases, in such a manner that essentially all of the crude oil vaporizes into the gases in said mixing zone;
(c) passing the effluent from the mixing zone into the reaction zone wherein the outlet temperature of the reaction zone is in the range of about 600°C. to about 1100°C., the pressure of the reaction zone is in the range of about 3 psig to about 30 psig, and the residence time of the crude oil and products thereof in the mixing zone and the reaction zone combined in about 6 to about 60 milliseconds;
(d) passing the effluent from the reaction zone into the quenching zone, said quenching having a sufficiently low temperature to stop the reaction essentially instant-aneously; and (e) recovering the effluent from the quenching zone.
Description
, 960'~
1~)475~3 FIELD OF THE INVENTION
This invention relates to an improvement in the processes presently used for the thermal cracking of hydro-carbons with hot gases and, more particularly, to a process adapted particularly to the cracking of crude oils.
DESCRIPTION OF THE PRIOR ART
Thermal cracking of hydrocarbon feedstocks has for many years been a major source for supplying the needs of the chemical industry with the most basic of chemicals such as ethylene and propylene, the former being used chiefly in the production of low and high density polyethyl-ene, ethylene oxide and vinyl chloride, and the latter for the production of isopropyl alcohol, acrylonitrile, poly-propylene and propylene oxide.
Natural gas, or various components thereof, and naphtha are currently the major feedstocks from which ethylene, propylene, and acetylene are derived by thermal cracking; however, shortages of these feedstocks at reasonabIe cost suggest that industry may eventually have to turn to heavier materials or crude oil in their stead.
One method of thermal cracking involves introduc-ing liquid feedstock into a reactor in atomized form together wtih superheated steam and/or another hot gas, which supplies the heat necessary for the endothermic cracking reaction. The introduction of the feedstock and hot gas is accomplished in such a manner that the components are thoroughly mixed and the high temperatllre is uniformly and rapidly established throughout the incoming feedstock.
While prior art processes for carrying out this general method are satisfactory for natural gas and naphtha ~Ji!
< 9609 feedstocks, they leave much to be desired in the field of crude oil cracking in that yields have been low and ~oke d,eposition has caused severe operating difficulties.
In view of the uneconomical results obtained when prior art processes are applied to crude oil cracking, a constant effort is being made to upgrade these processes so that they will efficiently accept crude oil feedstocks, but this goal has until now proved elusive.
SUMMARY OF THE INVENTION
An object of this invention, therefore, is to provide a process for cracking crude oil which has higher yields, particularly of ethylene, propylene and acetylene, than have been previously achieved together with improved operating characteristics.
Other objects and advantages will become apparent hereinafter, According to the present invention, such a process has been discovered for the cracking of crude oil to provide lower olefins, said process being carried out in a system comprising a mixing zone and an adiabatic reaction æone, each of said zones having an upstream end and a downstream end, the downstream end of the mixing zone being contiguous with the upstream end of the reaction zone, wherein both of said zones are in open relationship with each other and have a common geometrical axis running from the upstream end of the mixing zone through the downstream end of the reaction zone, and a quenching zone, comprising the following steps:
(a) introducing into the mixing zone in a direction about perpendicular to the axis, a mixture of combustion ' 9609 gases, produced from the essentially complete combustion of a fuel gas and oxygen mixed together with steam, at an inlet temperature of about 1000C. to about 2400~c.;
(b) introducing into the mixing zone in a downstream axial direction, crude oil, in a ratio of about 0.5 to about 1 part by weight of crude oil per part by weight of gases, in such a manner that essentially all of the crude oil vaporizes into the gases in said mixing zone;
(c) passing the effluent from the mixing zone into the reaction zone wherein the outlet temperature of the reaction zone is in the range of about 600C. to about 1100C., the pressure of the reaction zone is in the range of about 3 psig to about 30 psig, and the residence time of the crude oil and products thereof in the mixing zone and the reaction zone combined is about 6 to about 60 milli-seconds;
(d) passing the effluent from the reaction zone into the quenching zone, sai~ quenching zone having a sufficiently low temperature to stop the reaction essentially instant-aneously; and (e) recovering the effluent from the quenching zone.
A preferred mode substitutes the following steps for step (a), above:
(A) introducing into a burner zone under conditions Of high turbulence (i) at at least one point of entry, oxygen at an inlet pressure of about 15 psig to about 150 psig.
(ii) at at least one other, but separate, ~ S)47S~3 point of entry, hydrogen and from ~ to about 90 parts by weight of another ~uel gas per part by weight of hydrogen at a total inlet pressure of about 15 psig to about 150 psig, and (iii) at at least one of the points of entry set forth in (i) and (ii), steam at an inlet pressure of 15 psig to about 150 psig;
wherein the ratio of oxygen to steam is about 0.1 part by weight to about 50 parts by weight of oxygen per part by weight of steam and wherein pressure, rate of flow> temperature, and turbulence are maintained at sufficient levels to provide an essentially homogeneous gas mixture and essentially complete combustion thereof;
the burner zone outlet temperature is in the range of about 1200C. to about 2600C.; and the burner zone pressure is in the range of about 15 psig to about 150 psig;
and igniting said gas mixture to form together with the steam a mixture of combustion gases;
(B) introducing the gases from the burner zone into the mixing zone in a direction about perpendicular to the axis through at least one constricted throat section, the constriction being of such cross-section relative to the burner zone that the gases are accelerated when passing therethrough, wherein the mixing zone is constructed in ~47S43 9609 such a manner that thè gases expand on entry into said mixing zone.
BRIEF DESC~IPTION OF THE DRAWING
The sole figure ls an illustrative schematic diagram of a zoned apparatus in which the process of the present invention can be carried out.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The type of apparatus, many of the techniques and the terminology used here have been disclosed previously.
A representative publication is United States Patent
1~)475~3 FIELD OF THE INVENTION
This invention relates to an improvement in the processes presently used for the thermal cracking of hydro-carbons with hot gases and, more particularly, to a process adapted particularly to the cracking of crude oils.
DESCRIPTION OF THE PRIOR ART
Thermal cracking of hydrocarbon feedstocks has for many years been a major source for supplying the needs of the chemical industry with the most basic of chemicals such as ethylene and propylene, the former being used chiefly in the production of low and high density polyethyl-ene, ethylene oxide and vinyl chloride, and the latter for the production of isopropyl alcohol, acrylonitrile, poly-propylene and propylene oxide.
Natural gas, or various components thereof, and naphtha are currently the major feedstocks from which ethylene, propylene, and acetylene are derived by thermal cracking; however, shortages of these feedstocks at reasonabIe cost suggest that industry may eventually have to turn to heavier materials or crude oil in their stead.
One method of thermal cracking involves introduc-ing liquid feedstock into a reactor in atomized form together wtih superheated steam and/or another hot gas, which supplies the heat necessary for the endothermic cracking reaction. The introduction of the feedstock and hot gas is accomplished in such a manner that the components are thoroughly mixed and the high temperatllre is uniformly and rapidly established throughout the incoming feedstock.
While prior art processes for carrying out this general method are satisfactory for natural gas and naphtha ~Ji!
< 9609 feedstocks, they leave much to be desired in the field of crude oil cracking in that yields have been low and ~oke d,eposition has caused severe operating difficulties.
In view of the uneconomical results obtained when prior art processes are applied to crude oil cracking, a constant effort is being made to upgrade these processes so that they will efficiently accept crude oil feedstocks, but this goal has until now proved elusive.
SUMMARY OF THE INVENTION
An object of this invention, therefore, is to provide a process for cracking crude oil which has higher yields, particularly of ethylene, propylene and acetylene, than have been previously achieved together with improved operating characteristics.
Other objects and advantages will become apparent hereinafter, According to the present invention, such a process has been discovered for the cracking of crude oil to provide lower olefins, said process being carried out in a system comprising a mixing zone and an adiabatic reaction æone, each of said zones having an upstream end and a downstream end, the downstream end of the mixing zone being contiguous with the upstream end of the reaction zone, wherein both of said zones are in open relationship with each other and have a common geometrical axis running from the upstream end of the mixing zone through the downstream end of the reaction zone, and a quenching zone, comprising the following steps:
(a) introducing into the mixing zone in a direction about perpendicular to the axis, a mixture of combustion ' 9609 gases, produced from the essentially complete combustion of a fuel gas and oxygen mixed together with steam, at an inlet temperature of about 1000C. to about 2400~c.;
(b) introducing into the mixing zone in a downstream axial direction, crude oil, in a ratio of about 0.5 to about 1 part by weight of crude oil per part by weight of gases, in such a manner that essentially all of the crude oil vaporizes into the gases in said mixing zone;
(c) passing the effluent from the mixing zone into the reaction zone wherein the outlet temperature of the reaction zone is in the range of about 600C. to about 1100C., the pressure of the reaction zone is in the range of about 3 psig to about 30 psig, and the residence time of the crude oil and products thereof in the mixing zone and the reaction zone combined is about 6 to about 60 milli-seconds;
(d) passing the effluent from the reaction zone into the quenching zone, sai~ quenching zone having a sufficiently low temperature to stop the reaction essentially instant-aneously; and (e) recovering the effluent from the quenching zone.
A preferred mode substitutes the following steps for step (a), above:
(A) introducing into a burner zone under conditions Of high turbulence (i) at at least one point of entry, oxygen at an inlet pressure of about 15 psig to about 150 psig.
(ii) at at least one other, but separate, ~ S)47S~3 point of entry, hydrogen and from ~ to about 90 parts by weight of another ~uel gas per part by weight of hydrogen at a total inlet pressure of about 15 psig to about 150 psig, and (iii) at at least one of the points of entry set forth in (i) and (ii), steam at an inlet pressure of 15 psig to about 150 psig;
wherein the ratio of oxygen to steam is about 0.1 part by weight to about 50 parts by weight of oxygen per part by weight of steam and wherein pressure, rate of flow> temperature, and turbulence are maintained at sufficient levels to provide an essentially homogeneous gas mixture and essentially complete combustion thereof;
the burner zone outlet temperature is in the range of about 1200C. to about 2600C.; and the burner zone pressure is in the range of about 15 psig to about 150 psig;
and igniting said gas mixture to form together with the steam a mixture of combustion gases;
(B) introducing the gases from the burner zone into the mixing zone in a direction about perpendicular to the axis through at least one constricted throat section, the constriction being of such cross-section relative to the burner zone that the gases are accelerated when passing therethrough, wherein the mixing zone is constructed in ~47S43 9609 such a manner that thè gases expand on entry into said mixing zone.
BRIEF DESC~IPTION OF THE DRAWING
The sole figure ls an illustrative schematic diagram of a zoned apparatus in which the process of the present invention can be carried out.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The type of apparatus, many of the techniques and the terminology used here have been disclosed previously.
A representative publication is United States Patent
2,934,410 to Smith issued on April 26, 196D.
The instant process is particularly adapted to the cracking of crude oils or deasphalted crude oils containing 0 to about 3 percent by weight of sulfur based on the weight of the crude oil. It is preferred that at least about 0.3 percent by weight of sulfur be present in the feedstock because the sulfur is found to enhance the production of unsaturates. The sulfur can be present in the crude oil as it is obtained from natural sources or it can be introduced into the crude oil wholly or partially to make up the desired percentages. Examples of sulfur bearing crude oils which can be used are obtainable from Arabia and Iran.
An example of a crude oil to which sulfur can be added is obtainable from Penrlsylvania.
A preferred sulfur containing crude oil is Arabian Light Crude Oil. The composition of a typical ~rabian Crude Oil is as follows:
: -~, 1(~475~3 gravity, API:34 (API = American Petroleum Institute) Sulfur, weight %: 1.3 viscosity SUS at 100F.: 45 (SUS = Saybolt Universal pourpoint degrees F: -5. Seconds~
C-4 and lighter %: 2.3 It should be noted that subject process can be applied to crude oils, which do not contain sulfur;
however, the same level of optimization is not reached.
The underlying theory supporting the use of sulfur containing crudes is that, at the process temperatures, the combustion gases form low molecular weight sulfur cornpounds such as hydrogen sulfide, which give higher yields of ethylene and other unsaturates in the cooler end of the adiabatic reactor, described further below, as a result of hlgher free radical concentrations.
Whether or not the crude oil contains sulur, the process described here is adapted to handle those high boiling fractions, which cannot be vaporized at 500C. at normal pressures.
Apparatus-wise, the essentials of the system described here are an adiabatic reactor and a quenching zone, which can be an integral part of the reactor or independent thereof. In the preferred mode, a burner and constricted throat sections play a prominent role. Inlet nozzles or other inlet means and various fittings round out the picture.
The burner can be of the type represented by United States patent 3,074,469. It can be made of varlous metals and metal alloys, the pre~erred materlal being stainless steel, e.g., AISI (American ~ 9609 ~0475~3 Iron and Steel Institute) type 321 stainless steel.
Other representative materials from which the reactor can be made are AISI type 310 stainless steel and copper. Ceramic burners can also be used.
The preferred burners have mixing devices and can be operated under conditions to insure the instantaneous and complete mixing of the fuel, oxygen and steam.
Various means for cooling the burner are available such as passing steam or water through jackets.
The construction of the burner is such that the combustion gases can be in a highly turbulent state within the burner. The structure of the internal por-tion, the rate and direction of flow of the gases entering the burner9 the temperature and pressure, all combine to provide essentially complete combustion and the avoidance of having ur.combusted gases in the reaction zone that detract from the efficiency of the process.
In a typical burner, oxygen is introduced through an oxygen inlet line along the axis of the burner zone. The axis, of course, is not a physical structure, but a geometrical location. The burner zone is generally a modified cylindrical tube, the dimensions of which are not critical although the larger the tube or chamber, the more gases it can ~ 047543 handle. Various characteristics of the burner zone were described above. There can be several oxygen inlets preferably parallel to the axis of the zone, but they can be at various angles to the axis or per-pendicular and spread along the zone at various intervals. It is preferred, however, that the oxygen, as well as the fuel gas and steam, be introduced at/or near the upstream end of the burner zone. The total oxygen inlet pressure is about ~ psig (pounds per square inch gauge) to about 150 psig and is preferably about 2~ psig to about 40 psig.
It is preferred that the fuel gas enter the burner zone substantially perpendicular to the flow of oxygen into the zone; however, aside from the requirement that the oxygen and fuel gas enter at separate points, the fuel gas can be introduced at one or more points in the burner zone parallel, perpen-dicular, or at various angles to and intervals along the axis of the zone.
The fuel gas is made up of hydrogen and from 0 to about 90 parts by weight of another fuel gas per part by weight of hydrogen. The other fuel gases are preferably methane or propane, ~ut can be any gaseous . , .
- or liquid fuel.
It is preferred to use either hydrogen alone - or a ratio of about 1 to about 50 parts by weight of other fuel gas per part by weight of hydrogen. The ~-~ total inlet pressure of the hydrogen and other fuel ,, ,.~
gas is about 15 psig to about 150 psig, and preferably bout 20 psig to about 40 psig.
At one of the points of entry for the oxygen or the fuel gas or at both, steam is introduced into the burner zone. There is no restriction here on the entry of steam at all or any points together with the oxygen and/or ~uel gas; however, the following scheme is preferred, i.e, the steam enters the burner zone through the oxygen inlet and/or the hydrogen inlet at a total inlet pressure of about 15 psig to about 150 psig and preerably about 20 psig to about 40 psig.
The ratio o~ oxygen to steam is about 0.1 part by weight to about 50 parts by weight o~ oxygen per part by weight of steam and ~referably about 0.5 part by weight to about 10 parts by weight ol oxygen per part by weight of steam, .. .. . .
Steam can be introduced at both the oxygen inlet and the hydrogen inlet to assist in the intense mixing in the burner zone and promote homogeneity.
I~ the oxygen is not mixed properly and essentially complete combustion is not attained, the oxygen gets into the mixing zone alld the reactor zone and destroys the crude oil by forming the usual carbon oxide compounds.
Advantages of steam mixing in the burne-c zone, in addition to more complete combustion, are the lowering of tempera-tures and associated heat losses in the burner zone and the lowering of the overali heat losses as a result of the avoidance of secondary steam-mixing chambers. It is a featu~e of this invention tha~ no steam per se is i~troduced into the mixi~g zone and reaction zone às a cracking medium.
The steam, prior to its introduction into the burner zone, is superheated to a temperature of about 200C, to about 1200C. and preferably about 700C.
to about 1100C. by conventional methods.
The ratio of fuel gas to oxygen is about stoichiometric and preferab~y is a slightly fuel rich mixture.
The pressure inside the burner zone is about 15 psig to about 150 psig and preferably about 20 psig to about 40 psig; and the outlet temperature is about 1200C. to about 2600C. and preferably about 1900C.
to about 2400C.
A fuel-oxygen mixture is ignited at a point in the burner zone usually near the inlet with an igniter. Essentially complete combustion is determined by conventional analytical techniques and adjustments are made to the process conditions to attain this goal.
In view of the high temperatures involved, the mixture of combustion gases found are not completely in the molecular state, but are dissociated gases. They will be referred to as a mixture of combustion gases.
Referring to the drawing a brief description of which is set-forth hereinabove:
The unnumbered parallel broken lines perpendicu-lar to axis 6 divide the diagram of the apparatus into .
1~47543 contiguous zones. It is understood by those skilled in the art th~t, in practice, these zones are not sharply de.fined and that their functions may overlap.
The mixture of combustion gases (sometimes referred to as the mixture or gase~3 passes from the burner zone (not shown) into mixing zone 1 through constricted throat sections 4. Conven~ional connections are used between the burner and the throat sections, and the connections, which can be in the form of pipes or tubes, are preferably short and insulated to prevent heat loss.
These sections numbered 4 are tubes having a much narrower cross-section than the burner zone or mixing zone 1, There can be from one to twenty constricted throat sections depending on the size of the burner zone and mixing zone. Preferably there are 4 to 12 constricted throat sections connecting the burner zone with the mixing zone, The diameter of each section 4 and the number of constricted throat sections is selected by determining the best combination to handle all of the combustion gases needed for cracking and, at the same time, maintain a suitable pressure in the burner. Each section 4 can be a cylindrical tube, a cone shaped section similar to a nozzle, or a tube of varying cross-section such as a venturi.
The two constricted throat sections 4 in the draw-ing are opposite one another as shown by common geometrical axis 7, the flow of gases from each meeting at about the center of zone 1. It will be noted that while the mixture ~75~3 of gases is introduced initially in a direction aboutperpendicular to axis 6, the gases expand immediately after entry into the mixing zone and fan out. Common geometrical axis 7 illustrates the initial direction of the gases. Although the angle of initial dixection can vary from the perpendicular somewhat, an angle of more than about 20 degrees upstream(plus) relative to axis 7 and an angle of more than about 45 degrees downstream (minus) relative to axis 7 are not recommended. The objective is to operate as close to the perpendicular as possible to achieve optimum cross-current flow and to have the various streams of combustion gases converging at about the center of the mixing zone, and the throat sections are placed accordingly. Assuming mixing zone 1 to be cylindrical having an axis 6, it is seen that sections 4 are located on the perimeter of the cylinder 180 from each other, and where additional constricted throat sections are used, the preferred locations are equidistant from each other, e.g., three sections are located 120 apart; four sections 90 apart; five sections 72 apart, etc., their axes about perpendicular to axis 6 as for throat sections 4. The throat sections are preferably at the same distance from the upstream end of the mixing zone although these distances can be varied somewhat depending on the configuration of the reactor and the number of throat sections desired.
The length of each constricted throat section 4 is short enough to avoid unnecessary heat losses. There is a temperature drop at the outlet of section 4 due to the expansion of the gases into the mixing zone. The determination of this temperature (which can be called the inlet temperature of the mixing zone) has its origin in the selection of burner pressure and temperature and reactor pres-sure.
The velocity of the gases in the th~oat preferably is subsonic even though the gases are accelerating there. Thus the velocity approaches, but does not reach sonic . 9609 ~047543 velocity, Supersonic velocity can aLso be used ifdesired, however.
The mixture of combustion gases then enters the much wider mixing zone where the gases expand. Although the gases enter the mixing zone at the outlet velocity derived from the constricted throat section the velocity is slowed by the expansionto that of about200 feet per second to about 600 feet per second and preferably about 300 feet per second to about 550 feet per second.
The crude oil is then introduced into atomiza-tion zone 8.
Two crude oil inlets 2 are shown in the drawing at the upstream end of atomization zone 8. As the name of the zone indicates, this is where the crude oil is placed in a form preparatory to its being mixed with the combustion gases. Although these inlets 2 are each depicted as a simple line various kinds of injection apparatus can be used to get the crude oil into zone 8 in atomized form and preferably as cone shaped sprays 3.
The crude oil can be introduced by itself or together with an inert carrier such as steam; however, the carrier is not at cracking temperatures.
The crude oil then proceeds into mixing zone 1 immediately downstream from atomization zone 8. The combustion gases stream into this zone. The term "immed-iately" is considered here to mean that the atomized crude oil, i.e., the crude oil droplets, is permitted to first enter the cone shaped pattern before the mixing zone begins; however, the upstream edge of the mixing zone encroaches on the downstream end of the cone so that, in effect, the atomization zone and the mixing zone ~ 9609 overlap. The reaction or cracking begins in the mixing zone. On the downstream side of the mixing zone, again overlapping, is zone 9 where the bulk of the cracking takes place. Preferably, a plug flow configuration is used here, and a throat may be used to assist in preventing coke formation.
Although the crude oil inlets are preferably at the beginning of the atomization zone, they can be located farther downstream. This is not practical, however, because it only means that the mixing zone has to be moved farther downstream thus wasting apparatus space. There can be 1 to 20 crude oil inlets and there are preferably 8 to 14 crude oil inlets spaced to get the best droplet distribution in the atomization zone.
Prior to the introduction of the crude oil intô atomization zone 8, the crude oil is preferably preheated to temperatures in the range of about 50C.
to about 400C. and, preferably, about 250C. to about 350C. The preheating step is preparatory to handling the crude oil in theapparatus,which, as will be described below, is controlled in terms of crude oil viscosity and temperature so that the crude oil does not become too vlscous prior to vaporization and, on the other hand, so that it does not vaporize prior to reaching the nozzle.
As noted, the crude oil is introduced in a downstream direction through crude oil inlets 2.
The preferred mode i8 a spray in the shape of hollow or full right circular cone 3 (a cone that is generated by _16-` 9609 1()475~3 thc rotation of a right triangle about one of its ~-legs as axis) wherein the base of the cone is down-stream from the apex of the cone; the axis of the cone is essentially parallel to the flow of the gases or axis 6; the apex angle of the cone is about 15 degrees to about 140 degrees and preferably about 30 degrees to about 100 de~rees, the frustrum of the cone closest to the apex is comprised of a film of crude oil, which breaks up into ligaments and then to droplets of crude o~l having a size in the range of about 10 microns to about 100 microns and, preferably, less than about 50 microns. The size of the droplets given are minimum and maximum sizes for at least about ninety percent of the droplets, It is preferred that the droplet size be as small as possible.
The introduction of the crude oil in the shape of a cone is created by the selection of a device for inlet 2, generally, a type of nozzle, which under the correct conditions of pressure, rate of flow, temperature, and viscosity will provide a spray which takes the form of the described cone, A hydraulic hollow or full cone swirl nozzle is one such type of nozzle, The apex and the base of the cone are not clearly delineated in actual practice, Therefore, the apex angle is measured by simply extending the sides of the cone until they meet at a point and then measuring the angle there-between, The base of the cone is transitory since it cannot be determined exactly where the droplets of spray pass from the cone into the stream of combustion gases thus the overlap between the atomization zone and the mixing zone. Since the crude oil spray takes on a cone-` 9609 10475~3 shape and the mixture of gases expands and fans out, it is apparent that the two meet at a variety of angles;
however, the general flow of the mixture of combustion gases can be described as cross-current to the flow of the crude oil. In practice of the preferred mode, the axes, e.g., axes 7, of the throat sections are set so that they meet axis 6 and this insures good cross-current flow with a uniform distribution of combustion gases in the mixing zone.
Various types of nozzles can be used for the introduction o~ crude oil into the atomization zone via a cone-shaped spray. The nozzles are generally made of stainless steel, e.g., AISI type 321 or AISI
type 310, and may be cooled with various types of coolants such as water or steam by passing the coolant through a jacket surrounding the crude oil inlet 2.
Nozzles less than 10 GPM (GP~ = U.S. gallons per minute) in size are suggested. The nozzles can be inserted into the apparatus at various angles, which may be helpful in temperature control, provided, however, that the spray enters the atomization zone as described above.
Suitable nozzles can be classified, in order of increasing particle size, as follows: two-fluid nozz~es, hydraulic hollow cone nozzles and hydraulic flat spray nozzles.
The crude oil is injected into the mixture of combustion gases at a ratio of about 0.5 to about one part by weight of crude oil per part by weight of ~ 75~3 gases, i.e., mixture of combustion gases, and, prefer-ably, in a ratio of aboutO.70 to about 1 part of crude oil per part of gases and under a total inlet pressure of about 100 psig to about 1000 psig and preferably about 500 psig to about 800 psig.
The temperature of the mixture of combustion gases and the inlet temperature of the crude oil main-tain the viscosity of the crude oil below about 10 centipoises and, preferably, below about 1.25 centipoises, prior to vaporization and prevent the crude oil from vaporizing at its inlet pressure prior to and in the nozzle.
The temperature of the mixture of combustion gases is most easily maintained by keeping the a~ex of the cone as close to the mixing zone as practicable so that, along with the insulating qualities of the materials used to construct the apparatus, ve-y little heat loss occurs in transit.
Simultaneous control of the inlet tempera-ture of the crude oil by using a jacketed crude oil inlet with a coolant passing therethrough assists in maintaining the correct viscosity and, at the same time, avoiding vaporization. The temperature of the combustion gases at ~he region of injection is, therefore, maintained at aboutlooooc to about 2400OC.
and, preferably, about 1700c. to about 2200C. (this can be considered the mixing zone inlet temperature), and the point of control, ~hen, is at the coolant in the `` 9609 1~)47543 nozzle where an adjustment of crude oil inlet tempera-ture is made to compensate for the tèmperature of the combustion gases and the inlet pressure of the crude oil. Inlet pressure can also be adjusted within the above-mentioned limits. These adjustments achieve the correct viscosity and prevent vaporization of the crude oil prior to and in the no~zle.
Viscosity control agents can also be used, if desired. The advantage of these agents is that adjustments can be directed solely to the avoidance of vaporization, which simplifies the process somewhat It should be noted that the foregoing provide maintenance of the desired viscosity when the crude oil is in the film,ligaments, and droplet stages, i.e.
prior to vaporization.
The temperature of the mixture of combustion gases in the region of injection into the mi~ing zone (it should be remembered that this mixture includes the products of the combustion of oxygen with the fuel gas plus the steam in partially dissociated form) is generally determined from heat balance calculations or from flow-pressure measurements across the constricted throat section. Inlet steam temperatures and tempera-tures in the downstream portion of the apparatus are measured with thermocouples.
The outlet temperature of reac~ion zone 9 is maintained in the range of about 600C. to about 1100C., and, preferably~ in the range of about 800C
9609 ~`
10~7~43 to about 1000C.; the pressure of the reaction zone is maintained in the range of about 3 psig to about 30 psig and, preferably, about 10 psig to about 25 psig; and the~residence time of the crude oil and products thereof in the mixing zon~ and r-eaction zone combined is kept within about 6 milliseconds to about 60 milliseconds and, preferably, about lO to 40 milliseconds.
Heat loss control has been mentioned previously. One of the ways heat loss is controlled is through the materials used in constructing the apparatus, particularly the reaction zone. Alumina mullite, zirconia, graphite, silicon carbide, and magnesia can be used with alumina or mullite being preferred as liners for a stainless steel reactor.
The burner and apparatusinlet portion are liquid cooled, in any case, to avoid excessive temperatures. Stain-less steel fittings can be used. Preferred stainless steels are AISI types 310, 321, 330, and 333. The amount of nickel used in contact with the reactants 2b is limited or avoided altogether since it causes carbon formation and promotes CO and C02 formation. Loss of heat contributes to poor economics due to poor thermal efficiency.
The drawing has been referred to as an apparatus. In practice, the atomization zone, the mixing zone, and the reaction zone can be a piece of apparatus called an adiabatic reactor. Quenching zone 10 and recovery zone ll can be integral parts of the reactor or 1~1475~3 separate, the latter being the usual case. The reactoris preferably a hollo~ cylindrical tube having a length to d~ameter ~atio of aBout 5:1 to aBout 50:1 and prefer-ably about 7:1 to about 20:1.
Many types of reactors can be used, e.g., those described in United States Patents 3,959,401 and
The instant process is particularly adapted to the cracking of crude oils or deasphalted crude oils containing 0 to about 3 percent by weight of sulfur based on the weight of the crude oil. It is preferred that at least about 0.3 percent by weight of sulfur be present in the feedstock because the sulfur is found to enhance the production of unsaturates. The sulfur can be present in the crude oil as it is obtained from natural sources or it can be introduced into the crude oil wholly or partially to make up the desired percentages. Examples of sulfur bearing crude oils which can be used are obtainable from Arabia and Iran.
An example of a crude oil to which sulfur can be added is obtainable from Penrlsylvania.
A preferred sulfur containing crude oil is Arabian Light Crude Oil. The composition of a typical ~rabian Crude Oil is as follows:
: -~, 1(~475~3 gravity, API:34 (API = American Petroleum Institute) Sulfur, weight %: 1.3 viscosity SUS at 100F.: 45 (SUS = Saybolt Universal pourpoint degrees F: -5. Seconds~
C-4 and lighter %: 2.3 It should be noted that subject process can be applied to crude oils, which do not contain sulfur;
however, the same level of optimization is not reached.
The underlying theory supporting the use of sulfur containing crudes is that, at the process temperatures, the combustion gases form low molecular weight sulfur cornpounds such as hydrogen sulfide, which give higher yields of ethylene and other unsaturates in the cooler end of the adiabatic reactor, described further below, as a result of hlgher free radical concentrations.
Whether or not the crude oil contains sulur, the process described here is adapted to handle those high boiling fractions, which cannot be vaporized at 500C. at normal pressures.
Apparatus-wise, the essentials of the system described here are an adiabatic reactor and a quenching zone, which can be an integral part of the reactor or independent thereof. In the preferred mode, a burner and constricted throat sections play a prominent role. Inlet nozzles or other inlet means and various fittings round out the picture.
The burner can be of the type represented by United States patent 3,074,469. It can be made of varlous metals and metal alloys, the pre~erred materlal being stainless steel, e.g., AISI (American ~ 9609 ~0475~3 Iron and Steel Institute) type 321 stainless steel.
Other representative materials from which the reactor can be made are AISI type 310 stainless steel and copper. Ceramic burners can also be used.
The preferred burners have mixing devices and can be operated under conditions to insure the instantaneous and complete mixing of the fuel, oxygen and steam.
Various means for cooling the burner are available such as passing steam or water through jackets.
The construction of the burner is such that the combustion gases can be in a highly turbulent state within the burner. The structure of the internal por-tion, the rate and direction of flow of the gases entering the burner9 the temperature and pressure, all combine to provide essentially complete combustion and the avoidance of having ur.combusted gases in the reaction zone that detract from the efficiency of the process.
In a typical burner, oxygen is introduced through an oxygen inlet line along the axis of the burner zone. The axis, of course, is not a physical structure, but a geometrical location. The burner zone is generally a modified cylindrical tube, the dimensions of which are not critical although the larger the tube or chamber, the more gases it can ~ 047543 handle. Various characteristics of the burner zone were described above. There can be several oxygen inlets preferably parallel to the axis of the zone, but they can be at various angles to the axis or per-pendicular and spread along the zone at various intervals. It is preferred, however, that the oxygen, as well as the fuel gas and steam, be introduced at/or near the upstream end of the burner zone. The total oxygen inlet pressure is about ~ psig (pounds per square inch gauge) to about 150 psig and is preferably about 2~ psig to about 40 psig.
It is preferred that the fuel gas enter the burner zone substantially perpendicular to the flow of oxygen into the zone; however, aside from the requirement that the oxygen and fuel gas enter at separate points, the fuel gas can be introduced at one or more points in the burner zone parallel, perpen-dicular, or at various angles to and intervals along the axis of the zone.
The fuel gas is made up of hydrogen and from 0 to about 90 parts by weight of another fuel gas per part by weight of hydrogen. The other fuel gases are preferably methane or propane, ~ut can be any gaseous . , .
- or liquid fuel.
It is preferred to use either hydrogen alone - or a ratio of about 1 to about 50 parts by weight of other fuel gas per part by weight of hydrogen. The ~-~ total inlet pressure of the hydrogen and other fuel ,, ,.~
gas is about 15 psig to about 150 psig, and preferably bout 20 psig to about 40 psig.
At one of the points of entry for the oxygen or the fuel gas or at both, steam is introduced into the burner zone. There is no restriction here on the entry of steam at all or any points together with the oxygen and/or ~uel gas; however, the following scheme is preferred, i.e, the steam enters the burner zone through the oxygen inlet and/or the hydrogen inlet at a total inlet pressure of about 15 psig to about 150 psig and preerably about 20 psig to about 40 psig.
The ratio o~ oxygen to steam is about 0.1 part by weight to about 50 parts by weight o~ oxygen per part by weight of steam and ~referably about 0.5 part by weight to about 10 parts by weight ol oxygen per part by weight of steam, .. .. . .
Steam can be introduced at both the oxygen inlet and the hydrogen inlet to assist in the intense mixing in the burner zone and promote homogeneity.
I~ the oxygen is not mixed properly and essentially complete combustion is not attained, the oxygen gets into the mixing zone alld the reactor zone and destroys the crude oil by forming the usual carbon oxide compounds.
Advantages of steam mixing in the burne-c zone, in addition to more complete combustion, are the lowering of tempera-tures and associated heat losses in the burner zone and the lowering of the overali heat losses as a result of the avoidance of secondary steam-mixing chambers. It is a featu~e of this invention tha~ no steam per se is i~troduced into the mixi~g zone and reaction zone às a cracking medium.
The steam, prior to its introduction into the burner zone, is superheated to a temperature of about 200C, to about 1200C. and preferably about 700C.
to about 1100C. by conventional methods.
The ratio of fuel gas to oxygen is about stoichiometric and preferab~y is a slightly fuel rich mixture.
The pressure inside the burner zone is about 15 psig to about 150 psig and preferably about 20 psig to about 40 psig; and the outlet temperature is about 1200C. to about 2600C. and preferably about 1900C.
to about 2400C.
A fuel-oxygen mixture is ignited at a point in the burner zone usually near the inlet with an igniter. Essentially complete combustion is determined by conventional analytical techniques and adjustments are made to the process conditions to attain this goal.
In view of the high temperatures involved, the mixture of combustion gases found are not completely in the molecular state, but are dissociated gases. They will be referred to as a mixture of combustion gases.
Referring to the drawing a brief description of which is set-forth hereinabove:
The unnumbered parallel broken lines perpendicu-lar to axis 6 divide the diagram of the apparatus into .
1~47543 contiguous zones. It is understood by those skilled in the art th~t, in practice, these zones are not sharply de.fined and that their functions may overlap.
The mixture of combustion gases (sometimes referred to as the mixture or gase~3 passes from the burner zone (not shown) into mixing zone 1 through constricted throat sections 4. Conven~ional connections are used between the burner and the throat sections, and the connections, which can be in the form of pipes or tubes, are preferably short and insulated to prevent heat loss.
These sections numbered 4 are tubes having a much narrower cross-section than the burner zone or mixing zone 1, There can be from one to twenty constricted throat sections depending on the size of the burner zone and mixing zone. Preferably there are 4 to 12 constricted throat sections connecting the burner zone with the mixing zone, The diameter of each section 4 and the number of constricted throat sections is selected by determining the best combination to handle all of the combustion gases needed for cracking and, at the same time, maintain a suitable pressure in the burner. Each section 4 can be a cylindrical tube, a cone shaped section similar to a nozzle, or a tube of varying cross-section such as a venturi.
The two constricted throat sections 4 in the draw-ing are opposite one another as shown by common geometrical axis 7, the flow of gases from each meeting at about the center of zone 1. It will be noted that while the mixture ~75~3 of gases is introduced initially in a direction aboutperpendicular to axis 6, the gases expand immediately after entry into the mixing zone and fan out. Common geometrical axis 7 illustrates the initial direction of the gases. Although the angle of initial dixection can vary from the perpendicular somewhat, an angle of more than about 20 degrees upstream(plus) relative to axis 7 and an angle of more than about 45 degrees downstream (minus) relative to axis 7 are not recommended. The objective is to operate as close to the perpendicular as possible to achieve optimum cross-current flow and to have the various streams of combustion gases converging at about the center of the mixing zone, and the throat sections are placed accordingly. Assuming mixing zone 1 to be cylindrical having an axis 6, it is seen that sections 4 are located on the perimeter of the cylinder 180 from each other, and where additional constricted throat sections are used, the preferred locations are equidistant from each other, e.g., three sections are located 120 apart; four sections 90 apart; five sections 72 apart, etc., their axes about perpendicular to axis 6 as for throat sections 4. The throat sections are preferably at the same distance from the upstream end of the mixing zone although these distances can be varied somewhat depending on the configuration of the reactor and the number of throat sections desired.
The length of each constricted throat section 4 is short enough to avoid unnecessary heat losses. There is a temperature drop at the outlet of section 4 due to the expansion of the gases into the mixing zone. The determination of this temperature (which can be called the inlet temperature of the mixing zone) has its origin in the selection of burner pressure and temperature and reactor pres-sure.
The velocity of the gases in the th~oat preferably is subsonic even though the gases are accelerating there. Thus the velocity approaches, but does not reach sonic . 9609 ~047543 velocity, Supersonic velocity can aLso be used ifdesired, however.
The mixture of combustion gases then enters the much wider mixing zone where the gases expand. Although the gases enter the mixing zone at the outlet velocity derived from the constricted throat section the velocity is slowed by the expansionto that of about200 feet per second to about 600 feet per second and preferably about 300 feet per second to about 550 feet per second.
The crude oil is then introduced into atomiza-tion zone 8.
Two crude oil inlets 2 are shown in the drawing at the upstream end of atomization zone 8. As the name of the zone indicates, this is where the crude oil is placed in a form preparatory to its being mixed with the combustion gases. Although these inlets 2 are each depicted as a simple line various kinds of injection apparatus can be used to get the crude oil into zone 8 in atomized form and preferably as cone shaped sprays 3.
The crude oil can be introduced by itself or together with an inert carrier such as steam; however, the carrier is not at cracking temperatures.
The crude oil then proceeds into mixing zone 1 immediately downstream from atomization zone 8. The combustion gases stream into this zone. The term "immed-iately" is considered here to mean that the atomized crude oil, i.e., the crude oil droplets, is permitted to first enter the cone shaped pattern before the mixing zone begins; however, the upstream edge of the mixing zone encroaches on the downstream end of the cone so that, in effect, the atomization zone and the mixing zone ~ 9609 overlap. The reaction or cracking begins in the mixing zone. On the downstream side of the mixing zone, again overlapping, is zone 9 where the bulk of the cracking takes place. Preferably, a plug flow configuration is used here, and a throat may be used to assist in preventing coke formation.
Although the crude oil inlets are preferably at the beginning of the atomization zone, they can be located farther downstream. This is not practical, however, because it only means that the mixing zone has to be moved farther downstream thus wasting apparatus space. There can be 1 to 20 crude oil inlets and there are preferably 8 to 14 crude oil inlets spaced to get the best droplet distribution in the atomization zone.
Prior to the introduction of the crude oil intô atomization zone 8, the crude oil is preferably preheated to temperatures in the range of about 50C.
to about 400C. and, preferably, about 250C. to about 350C. The preheating step is preparatory to handling the crude oil in theapparatus,which, as will be described below, is controlled in terms of crude oil viscosity and temperature so that the crude oil does not become too vlscous prior to vaporization and, on the other hand, so that it does not vaporize prior to reaching the nozzle.
As noted, the crude oil is introduced in a downstream direction through crude oil inlets 2.
The preferred mode i8 a spray in the shape of hollow or full right circular cone 3 (a cone that is generated by _16-` 9609 1()475~3 thc rotation of a right triangle about one of its ~-legs as axis) wherein the base of the cone is down-stream from the apex of the cone; the axis of the cone is essentially parallel to the flow of the gases or axis 6; the apex angle of the cone is about 15 degrees to about 140 degrees and preferably about 30 degrees to about 100 de~rees, the frustrum of the cone closest to the apex is comprised of a film of crude oil, which breaks up into ligaments and then to droplets of crude o~l having a size in the range of about 10 microns to about 100 microns and, preferably, less than about 50 microns. The size of the droplets given are minimum and maximum sizes for at least about ninety percent of the droplets, It is preferred that the droplet size be as small as possible.
The introduction of the crude oil in the shape of a cone is created by the selection of a device for inlet 2, generally, a type of nozzle, which under the correct conditions of pressure, rate of flow, temperature, and viscosity will provide a spray which takes the form of the described cone, A hydraulic hollow or full cone swirl nozzle is one such type of nozzle, The apex and the base of the cone are not clearly delineated in actual practice, Therefore, the apex angle is measured by simply extending the sides of the cone until they meet at a point and then measuring the angle there-between, The base of the cone is transitory since it cannot be determined exactly where the droplets of spray pass from the cone into the stream of combustion gases thus the overlap between the atomization zone and the mixing zone. Since the crude oil spray takes on a cone-` 9609 10475~3 shape and the mixture of gases expands and fans out, it is apparent that the two meet at a variety of angles;
however, the general flow of the mixture of combustion gases can be described as cross-current to the flow of the crude oil. In practice of the preferred mode, the axes, e.g., axes 7, of the throat sections are set so that they meet axis 6 and this insures good cross-current flow with a uniform distribution of combustion gases in the mixing zone.
Various types of nozzles can be used for the introduction o~ crude oil into the atomization zone via a cone-shaped spray. The nozzles are generally made of stainless steel, e.g., AISI type 321 or AISI
type 310, and may be cooled with various types of coolants such as water or steam by passing the coolant through a jacket surrounding the crude oil inlet 2.
Nozzles less than 10 GPM (GP~ = U.S. gallons per minute) in size are suggested. The nozzles can be inserted into the apparatus at various angles, which may be helpful in temperature control, provided, however, that the spray enters the atomization zone as described above.
Suitable nozzles can be classified, in order of increasing particle size, as follows: two-fluid nozz~es, hydraulic hollow cone nozzles and hydraulic flat spray nozzles.
The crude oil is injected into the mixture of combustion gases at a ratio of about 0.5 to about one part by weight of crude oil per part by weight of ~ 75~3 gases, i.e., mixture of combustion gases, and, prefer-ably, in a ratio of aboutO.70 to about 1 part of crude oil per part of gases and under a total inlet pressure of about 100 psig to about 1000 psig and preferably about 500 psig to about 800 psig.
The temperature of the mixture of combustion gases and the inlet temperature of the crude oil main-tain the viscosity of the crude oil below about 10 centipoises and, preferably, below about 1.25 centipoises, prior to vaporization and prevent the crude oil from vaporizing at its inlet pressure prior to and in the nozzle.
The temperature of the mixture of combustion gases is most easily maintained by keeping the a~ex of the cone as close to the mixing zone as practicable so that, along with the insulating qualities of the materials used to construct the apparatus, ve-y little heat loss occurs in transit.
Simultaneous control of the inlet tempera-ture of the crude oil by using a jacketed crude oil inlet with a coolant passing therethrough assists in maintaining the correct viscosity and, at the same time, avoiding vaporization. The temperature of the combustion gases at ~he region of injection is, therefore, maintained at aboutlooooc to about 2400OC.
and, preferably, about 1700c. to about 2200C. (this can be considered the mixing zone inlet temperature), and the point of control, ~hen, is at the coolant in the `` 9609 1~)47543 nozzle where an adjustment of crude oil inlet tempera-ture is made to compensate for the tèmperature of the combustion gases and the inlet pressure of the crude oil. Inlet pressure can also be adjusted within the above-mentioned limits. These adjustments achieve the correct viscosity and prevent vaporization of the crude oil prior to and in the no~zle.
Viscosity control agents can also be used, if desired. The advantage of these agents is that adjustments can be directed solely to the avoidance of vaporization, which simplifies the process somewhat It should be noted that the foregoing provide maintenance of the desired viscosity when the crude oil is in the film,ligaments, and droplet stages, i.e.
prior to vaporization.
The temperature of the mixture of combustion gases in the region of injection into the mi~ing zone (it should be remembered that this mixture includes the products of the combustion of oxygen with the fuel gas plus the steam in partially dissociated form) is generally determined from heat balance calculations or from flow-pressure measurements across the constricted throat section. Inlet steam temperatures and tempera-tures in the downstream portion of the apparatus are measured with thermocouples.
The outlet temperature of reac~ion zone 9 is maintained in the range of about 600C. to about 1100C., and, preferably~ in the range of about 800C
9609 ~`
10~7~43 to about 1000C.; the pressure of the reaction zone is maintained in the range of about 3 psig to about 30 psig and, preferably, about 10 psig to about 25 psig; and the~residence time of the crude oil and products thereof in the mixing zon~ and r-eaction zone combined is kept within about 6 milliseconds to about 60 milliseconds and, preferably, about lO to 40 milliseconds.
Heat loss control has been mentioned previously. One of the ways heat loss is controlled is through the materials used in constructing the apparatus, particularly the reaction zone. Alumina mullite, zirconia, graphite, silicon carbide, and magnesia can be used with alumina or mullite being preferred as liners for a stainless steel reactor.
The burner and apparatusinlet portion are liquid cooled, in any case, to avoid excessive temperatures. Stain-less steel fittings can be used. Preferred stainless steels are AISI types 310, 321, 330, and 333. The amount of nickel used in contact with the reactants 2b is limited or avoided altogether since it causes carbon formation and promotes CO and C02 formation. Loss of heat contributes to poor economics due to poor thermal efficiency.
The drawing has been referred to as an apparatus. In practice, the atomization zone, the mixing zone, and the reaction zone can be a piece of apparatus called an adiabatic reactor. Quenching zone 10 and recovery zone ll can be integral parts of the reactor or 1~1475~3 separate, the latter being the usual case. The reactoris preferably a hollo~ cylindrical tube having a length to d~ameter ~atio of aBout 5:1 to aBout 50:1 and prefer-ably about 7:1 to about 20:1.
Many types of reactors can be used, e.g., those described in United States Patents 3,959,401 and
3,849,075. As noted above, a simple hollow cylindrical tube reactor of the plug flow type having a length to diameter ratio of about 7:1 to about 20:1 is most commonly llsed and is preferred.
An alternative configuration is one in which the atomization and mixing zones have a cyl-indrical shape and the reaction zone has a frusto-conical shape, the top or narrower part of the frustrum being contiguous with the boundary of the mixing zone and the base being at the downstream end of the reactor. The divergent half angle of the frustrum can be about 4 degrees to about 25 degrees.
The effluent from reaction zone 9 is then passed into quenching zone 10 which, in the drawing, is served by quench sprays 5. The temperature in the quenching zone must be sufficiently low to stop the reaction essentially instantaneously, which means in the present context stopping the reaction in less than about 10 milliseconds and preferably less than about 6 milli-seconds. Conventional quenching techniques can be used such as a heavy oil quench or a light oil quench with a heavy oil wall flush to avoid fouling. A water quench can also be used. Usually quench nozzles are used in conventional systems and the axes of the nozzles are ~s)47~s3 preferably about perpendicular to the f ow of the effluent, i.e., the quench spray or stream is direc~ed cross-current to the flow. The pressure drop across the quench zone is usually less than about one psi. Heat exchangers may be used in the quench zone as well as spray nozzles or other conventional quench means.
Although quench zone 10 in the drawing is depicted as covering a broader area than quench sprays 5, quenching does not begin until the effluent reaches the quenching apparatus. The area prior to the quenching apparatus, then, is still, in effect, part of the reaction zone and it should be understood that the residence time of the crude oil and products thereof mentioned heretofore covers the span of time beginning with contact of combust-ion gases with the crude oil in the mixing zone until the quench.
Pre-quenching may be used to bring the temperature down to the lower limit required in the reaction zone, i.e., about 600C.
The effluent then passes from the quenching zone and is recovered and separated by various conven-tional means in recovery zone 11. It contains hydrogen, methane, ethylene, acetylene, propylene, carbon monoxide, and carbon dioxide. Carbon and tar, as well as minor amounts of other materials such as aromatics, and various sulfur compounds are also present.
The following example illustrates the invention Parts, percentages, and ratios are by weight unless otherwise specified.
~0475~3 EXAMPLE
The process is run according to the scheme represented by the sole figur~ of the drawing and the process described above. The positioning of eight equidistant crude oil inlets and four constricted throat sections, which are used, and the quenching zone is similar to the drawing.
The burner (not shown in the drawing) is a modified Marquardt burner manufactured by the Marquardt Company of Van ~uys, California. Its shape is roughly that of a cylinder of varying diameters with a maximum internal diameter of 1.25 inch and a minimum internal diameter of 1 inch. The burner is fabricated from AISI
type 321 Stainless Steel.
Steam is introduced at an oxygen inlet of the burner (total steam = 62 pounds per hour).
Oxygen inlet temperature = ambient Fuel gas inlet temperature = ambient Steam inlet temperature = ~00C.
Oxygen inlet pressure = 30 psig Fuel gas: hydrogen = 5 pounds per hour (by weight) Hydrogen/oxygen/atom ratio = 2.0 Fuel gas inlet pressure = 30 psig Steam total inlet pressure = 30 psig Burner zone outlet temperature - 2300C.
(estimated) Burner zone pressure = 30 psig ~ -24-There are two pairs of constricted throat sections, which are also cylindrical tubes each having an internal diameter of 0.19 and spaced 90 from each other. They are constructed of the following material: AISI type 330 Stainless Steel.
-24~-1~)475~3 The outlet velocity of the gases in the constricted throat section: Mach number = 0.93. (estimate) The outlet temperature of the constricted throat section or inlet temperature of the mlxing zone = 2100C.
The reactor is a cylindrical tube having a length of 3 feet and a internal diameter of 2 inches.
The materials used for the reactor and its fittings are as follows: 2 inch diameter alumina inner tube, 1 inch thick mullite insulation, 4 inch diameter AISI
type 330 Stainless Steel.
The volume of the reactor - 1850 cubic centimeters.
Arabian Light Crude Oil is fed at a rate of 80 pounds per hour.
The ratio of crude oil feed to mixture of combustion gases = 0.75.
The inlet pressure of the crude oil = 600 psig.
The positioning of the inlet nozzles for the crude oil is 3 inches away from axis 7.
The apex angle of the cone shaped spray is 70.
The inlet temperature of the crude oil = 300C.
The viscosity of the crude oil at the nozzle tip is 1 centipoise.
The reactor outlet temperature = 850c.
The reactor pressure = 12.5 psig.
1~)47543 The residence time in the reactor zone = 30 milliseconds.
~uenching is accomplished by the spraying of water cross-current to the flow of the effluent.
The quench zone is a tubular extension of the reactor and is constructed of AISI type 330 Stain-less Steel.
The quenched gas temperature = 100C.
The quench time - 5 milliseconds (estimated).
The effluent is recovered from the quench zone and analyzed.
The yields* per 100 parts of crude oil feed are as follows:
Compound Parts methane 8.3 ethylene 32.8 acetylene 2.2 propylene 9.6 carbon monoxide) carbon dioxide ) 1.2 other 45 9 *The gas yields are measured by metering a cooled demisted gas stream using a dry gas meter.
The ga~ i5 then analyzed for all C3 and lighter com-ponents with on-line gas analyzers. A computer program is used to calculate yields on the basis of pounds per 100 pounds of eed.
An alternative configuration is one in which the atomization and mixing zones have a cyl-indrical shape and the reaction zone has a frusto-conical shape, the top or narrower part of the frustrum being contiguous with the boundary of the mixing zone and the base being at the downstream end of the reactor. The divergent half angle of the frustrum can be about 4 degrees to about 25 degrees.
The effluent from reaction zone 9 is then passed into quenching zone 10 which, in the drawing, is served by quench sprays 5. The temperature in the quenching zone must be sufficiently low to stop the reaction essentially instantaneously, which means in the present context stopping the reaction in less than about 10 milliseconds and preferably less than about 6 milli-seconds. Conventional quenching techniques can be used such as a heavy oil quench or a light oil quench with a heavy oil wall flush to avoid fouling. A water quench can also be used. Usually quench nozzles are used in conventional systems and the axes of the nozzles are ~s)47~s3 preferably about perpendicular to the f ow of the effluent, i.e., the quench spray or stream is direc~ed cross-current to the flow. The pressure drop across the quench zone is usually less than about one psi. Heat exchangers may be used in the quench zone as well as spray nozzles or other conventional quench means.
Although quench zone 10 in the drawing is depicted as covering a broader area than quench sprays 5, quenching does not begin until the effluent reaches the quenching apparatus. The area prior to the quenching apparatus, then, is still, in effect, part of the reaction zone and it should be understood that the residence time of the crude oil and products thereof mentioned heretofore covers the span of time beginning with contact of combust-ion gases with the crude oil in the mixing zone until the quench.
Pre-quenching may be used to bring the temperature down to the lower limit required in the reaction zone, i.e., about 600C.
The effluent then passes from the quenching zone and is recovered and separated by various conven-tional means in recovery zone 11. It contains hydrogen, methane, ethylene, acetylene, propylene, carbon monoxide, and carbon dioxide. Carbon and tar, as well as minor amounts of other materials such as aromatics, and various sulfur compounds are also present.
The following example illustrates the invention Parts, percentages, and ratios are by weight unless otherwise specified.
~0475~3 EXAMPLE
The process is run according to the scheme represented by the sole figur~ of the drawing and the process described above. The positioning of eight equidistant crude oil inlets and four constricted throat sections, which are used, and the quenching zone is similar to the drawing.
The burner (not shown in the drawing) is a modified Marquardt burner manufactured by the Marquardt Company of Van ~uys, California. Its shape is roughly that of a cylinder of varying diameters with a maximum internal diameter of 1.25 inch and a minimum internal diameter of 1 inch. The burner is fabricated from AISI
type 321 Stainless Steel.
Steam is introduced at an oxygen inlet of the burner (total steam = 62 pounds per hour).
Oxygen inlet temperature = ambient Fuel gas inlet temperature = ambient Steam inlet temperature = ~00C.
Oxygen inlet pressure = 30 psig Fuel gas: hydrogen = 5 pounds per hour (by weight) Hydrogen/oxygen/atom ratio = 2.0 Fuel gas inlet pressure = 30 psig Steam total inlet pressure = 30 psig Burner zone outlet temperature - 2300C.
(estimated) Burner zone pressure = 30 psig ~ -24-There are two pairs of constricted throat sections, which are also cylindrical tubes each having an internal diameter of 0.19 and spaced 90 from each other. They are constructed of the following material: AISI type 330 Stainless Steel.
-24~-1~)475~3 The outlet velocity of the gases in the constricted throat section: Mach number = 0.93. (estimate) The outlet temperature of the constricted throat section or inlet temperature of the mlxing zone = 2100C.
The reactor is a cylindrical tube having a length of 3 feet and a internal diameter of 2 inches.
The materials used for the reactor and its fittings are as follows: 2 inch diameter alumina inner tube, 1 inch thick mullite insulation, 4 inch diameter AISI
type 330 Stainless Steel.
The volume of the reactor - 1850 cubic centimeters.
Arabian Light Crude Oil is fed at a rate of 80 pounds per hour.
The ratio of crude oil feed to mixture of combustion gases = 0.75.
The inlet pressure of the crude oil = 600 psig.
The positioning of the inlet nozzles for the crude oil is 3 inches away from axis 7.
The apex angle of the cone shaped spray is 70.
The inlet temperature of the crude oil = 300C.
The viscosity of the crude oil at the nozzle tip is 1 centipoise.
The reactor outlet temperature = 850c.
The reactor pressure = 12.5 psig.
1~)47543 The residence time in the reactor zone = 30 milliseconds.
~uenching is accomplished by the spraying of water cross-current to the flow of the effluent.
The quench zone is a tubular extension of the reactor and is constructed of AISI type 330 Stain-less Steel.
The quenched gas temperature = 100C.
The quench time - 5 milliseconds (estimated).
The effluent is recovered from the quench zone and analyzed.
The yields* per 100 parts of crude oil feed are as follows:
Compound Parts methane 8.3 ethylene 32.8 acetylene 2.2 propylene 9.6 carbon monoxide) carbon dioxide ) 1.2 other 45 9 *The gas yields are measured by metering a cooled demisted gas stream using a dry gas meter.
The ga~ i5 then analyzed for all C3 and lighter com-ponents with on-line gas analyzers. A computer program is used to calculate yields on the basis of pounds per 100 pounds of eed.
Claims (18)
1. A process for the cracking of crude oil to provide lower olefins, said process being carried out in a system comprising an atomization zone, a mixing zone, an adiabatic reaction zone and a quenching zone, wherein each of said atomization, mixing and adiabatic reaction zones has an upstream end and a downstream end and a common geometrical axis running from the upstream end of the atomization zone through the downstream end of the reaction zone, the downstream end of the atomization zone being contiguous and in open relationship with the upstream end of the mixing zone, and the downstream end of the mixing zone being contiguous and in open relationship with the upstream end of the reaction zone, comprising the following steps:
(a) introducing into the mixing zone in a direction about perpendicular to said axis, a mixture of combustion gases produced from the essentially complete combustion of a fuel gas and oxygen mixed together with steam, at a subsonic velocity approaching sonic velocity and an inlet temperature of about 1000°C. to about 2400°C.;
(b) introducing crude oil into the upstream end of the atomization zone in a downstream axial direction and in such a manner that crude oil is converted into droplets in the atomization zone;
(c) passing the droplets of crude oil from the atomization zone into the gases in the mixing zone in a downstream axial direction in a ratio of about 0.5 to about 1 part by weight of crude oil per part by weight 27.
of gases and in such a manner that essentially all of the crude oil vaporizes into the gases in said mixing zone;
(d) passing the effluent from the mixing zone into the reaction zone wherein the outlet temperature of the reaction zone is in the range of about 600°C. to about 1100°C., the pressure in the reaction zone is in the range of about 3 psig to about 30 psig, and the residence time of the crude oil and products thereof in the mixing zone and the reaction zone combined is about 6 to about 60 milliseconds;
(e) passing the effluent from the reaction zone into the quenching zone, said quenching zone having a sufficiently low temperature to stop the reaction essentially instantaneously; and (f) recovering the effluent from the quenching zone.
(a) introducing into the mixing zone in a direction about perpendicular to said axis, a mixture of combustion gases produced from the essentially complete combustion of a fuel gas and oxygen mixed together with steam, at a subsonic velocity approaching sonic velocity and an inlet temperature of about 1000°C. to about 2400°C.;
(b) introducing crude oil into the upstream end of the atomization zone in a downstream axial direction and in such a manner that crude oil is converted into droplets in the atomization zone;
(c) passing the droplets of crude oil from the atomization zone into the gases in the mixing zone in a downstream axial direction in a ratio of about 0.5 to about 1 part by weight of crude oil per part by weight 27.
of gases and in such a manner that essentially all of the crude oil vaporizes into the gases in said mixing zone;
(d) passing the effluent from the mixing zone into the reaction zone wherein the outlet temperature of the reaction zone is in the range of about 600°C. to about 1100°C., the pressure in the reaction zone is in the range of about 3 psig to about 30 psig, and the residence time of the crude oil and products thereof in the mixing zone and the reaction zone combined is about 6 to about 60 milliseconds;
(e) passing the effluent from the reaction zone into the quenching zone, said quenching zone having a sufficiently low temperature to stop the reaction essentially instantaneously; and (f) recovering the effluent from the quenching zone.
2. The process defined in claim 1 wherein the direction in step (a) is about +20° to about -45°.
3. The process defined in claim 1 wherein the system additionally comprises a burner zone in which the combustion gases are produced, and wherein the combustion gases are passed from the burner zone and are introduced to the mixing zone in step (a) through at least one constricted throat section in which the velocity of the gases is subsonic, the constriction being of such cross-section relative to the burner zone that the subsonic velocity of the gases accelerates when passing therethrough and approaches said sonic velocity.
28.
28.
4. The process defined in claim 1 wherein the crude oil contains about 0.3 to about 3 percent by weight of sulfur based on the weight of the crude oil.
5. The process defined in claim 1 in which crude oil is introduced to step (b) as a cone-shaped spray, the base of the cone being downstream from the apex of the cone and comprising droplets of crude oil, and wherein, the droplets of crude oil pass to step (c) from the base of the cone.
6. The process defined in claim 1 wherein the atomization, mixing and reaction zones are in a hollow cylindrical tube having a length to diameter ratio of about 7:1 to about 20:1.
7. The process defined in claim 1 wherein the reaction zone has a frusto-conical shape, the narrower end of the frustum being upstream.
8. A process for the cracking of crude oil con-taining 0 to about 3 percent by weight of sulfur based on the weight of the crude oil to provide lower olefins, said process being carried out in a system consisting essentially of a burner zone, an atomization zone, a mixing zone, an adiabatic reaction zone, and a quenching zone, wherein each of said atomization, mixing and adiabatic reaction zones has an upstream end and a downstream end and a common geo-metrical axis running from the upstream end of the atomization zone through the downstream end of the reaction zone, the downstream end of the atomization zone being contiguous and in open relationship with the upstream end of the mixing zone, 29.
and the downstream end of the mixing zone being contiguous and in open relationship with the upstream end of the reaction zone, comprising the following steps:
(a) introducing into the burner zone under conditions of high turbulence (i) at at least one point of entry, oxygen at a total inlet pressure of about 15 psig to about 150 psig, (ii) at at least one other, but separate, point of entry, hydrogen and from 0 to about 90 parts by weight of another fuel gas per part by weight of hydrogen at a total inlet pressure of about 15 psig to about 150 psig, and (iii) at at least one of the points of entry set forth in (i) and (ii), steam at a total inlet pressure of about 15 psig to about 150 psig, wherein the ratio of oxygen to steam is about 0.1 part by weight to about 50 parts by weight of oxygen per part by weight of steam and wherein pressure, rate of flow, temperature and turbulence are maintained at sufficient levels to provide an essentially homogeneous gas mixture and essentially complete combustion thereof, and wherein the burner zone outlet temperature is in the range of about 1200°C. to about 2600°C. and the burner zone pressure is in the range of about 15 psig to about 150 psig, and igniting said gas mixture to form together with the steam a mixture of combustion gases;
(b) introducing the gases from the burner zone into the mixing zone in a direction about perpendicular to the axis through at least one constricted throat section, the velocity of the gases in the throat section being subsonic 30.
and the constriction being of such cross-section relative to the burner zone that the subsonic velocity of the gases accelerates when passing therethrough and approaches sonic velocity, wherein the mixing zone is constructed in such a manner that the gases expand on entry into said mixing zone;
(c) introducing crude oil into the upstream end of the atomization zone in a downstream axial direction and in such a manner that crude oil is converted into droplets, the inlet pressure of the crude oil being from about 100 to about 1000 psig;
(d) passing the droplets of crude oil into the gases in the upstream end of the mixing zone in a downstream direction about parallel to the axis, in a ratio of about 0.5 to about 1 part by weight of crude oil per part by weight of gases, and in such a manner that essentially all of the crude oil vaporizes into the gases in the mixing zone;
(e) passing the effluent from the mixing zone into the reaction zone wherein the outlet temperature of the reaction zone is in the range of about 600°C. to about 1100°C., the pressure in the reaction zone is in the range of about 3 psig to about 30 psig, and the residence time of the crude oil and products thereof in the mixing zone and the reaction zone combined is about 6 to about 60 milliseconds;
(f) passing the effluent from the reaction zone into a quenching zone having a sufficiently low temperature to stop the reaction essentially instantaneously; and (g) recovering the effluent from the quenching zone.
31.
and the downstream end of the mixing zone being contiguous and in open relationship with the upstream end of the reaction zone, comprising the following steps:
(a) introducing into the burner zone under conditions of high turbulence (i) at at least one point of entry, oxygen at a total inlet pressure of about 15 psig to about 150 psig, (ii) at at least one other, but separate, point of entry, hydrogen and from 0 to about 90 parts by weight of another fuel gas per part by weight of hydrogen at a total inlet pressure of about 15 psig to about 150 psig, and (iii) at at least one of the points of entry set forth in (i) and (ii), steam at a total inlet pressure of about 15 psig to about 150 psig, wherein the ratio of oxygen to steam is about 0.1 part by weight to about 50 parts by weight of oxygen per part by weight of steam and wherein pressure, rate of flow, temperature and turbulence are maintained at sufficient levels to provide an essentially homogeneous gas mixture and essentially complete combustion thereof, and wherein the burner zone outlet temperature is in the range of about 1200°C. to about 2600°C. and the burner zone pressure is in the range of about 15 psig to about 150 psig, and igniting said gas mixture to form together with the steam a mixture of combustion gases;
(b) introducing the gases from the burner zone into the mixing zone in a direction about perpendicular to the axis through at least one constricted throat section, the velocity of the gases in the throat section being subsonic 30.
and the constriction being of such cross-section relative to the burner zone that the subsonic velocity of the gases accelerates when passing therethrough and approaches sonic velocity, wherein the mixing zone is constructed in such a manner that the gases expand on entry into said mixing zone;
(c) introducing crude oil into the upstream end of the atomization zone in a downstream axial direction and in such a manner that crude oil is converted into droplets, the inlet pressure of the crude oil being from about 100 to about 1000 psig;
(d) passing the droplets of crude oil into the gases in the upstream end of the mixing zone in a downstream direction about parallel to the axis, in a ratio of about 0.5 to about 1 part by weight of crude oil per part by weight of gases, and in such a manner that essentially all of the crude oil vaporizes into the gases in the mixing zone;
(e) passing the effluent from the mixing zone into the reaction zone wherein the outlet temperature of the reaction zone is in the range of about 600°C. to about 1100°C., the pressure in the reaction zone is in the range of about 3 psig to about 30 psig, and the residence time of the crude oil and products thereof in the mixing zone and the reaction zone combined is about 6 to about 60 milliseconds;
(f) passing the effluent from the reaction zone into a quenching zone having a sufficiently low temperature to stop the reaction essentially instantaneously; and (g) recovering the effluent from the quenching zone.
31.
9, The process defined in claim 8 wherein oxygen and steam are introduced at one point of entry located at the upstream end of the burner zone and along the axis of the burner zone in a downstream direction, and hydrogen and another fuel gas are introduced at one point of entry located at the upstream end of the burner zone and about perpendicular to said axis.
10. The process defined in claim 8 wherein oxygen and steam are introduced at one point of entry located at the upstream end of the burner zone and along the axis of the burner zone in a downstream direction, and hydrogen, another fuel gas, and steam are introduced at one point of entry located at the upstream end of the burner zone and about perpendicular to said axis.
11. The process defined in claim 8 wherein the direction in step (b) is about +20° to about -45°.
12. The process defined in claim 8 wherein the viscosity of the crude oil prior to vaporization is less than 10 centipoise.
13. The process defined in claim 8 wherein the crude oil is introduced to step (c) at at least one point of entry as a cone-shaped spray, the base of the cone being downstream from the apex of the cone and wherein the droplets of crude oil pass to step (d) from the base of the cone.
14. The process defined in claim 8 wherein the size of at least about ninety percent of the crude oil drop-lets in step (c) is in the range of about 10 to about 100 microns.
32.
32.
15. The process defined in claim 8 wherein the reaction zone has a frusto-conical shape, the narrower end of the frustrum being upstream.
16. A process for the cracking of crude oil con-taining about 0.3 to about 3 percent by weight of sulfur based on the weight of the crude oil to provide lower ole-fins, said process being carried out in a system consisting essentially of a burner zone, an atomization zone, a mixing zone, an adiabatic reaction zone, and a quenching zone, wherein the atomization, mixing and reaction zones each have an upstream end and a downstream end, the downstream end of the atomization zone being contiguous and in open relationship with the upstream end of the mixing zone, the downstream end of the mixing zone being contiguous and in open relationship with the upstream end of the reaction zone, and wherein the atomization, mixing and reaction zones are in a hollow cylindrical tube having a length to diameter ratio of about 7:1 to about 20:1 and have a common geometrical axis running from the upstream end of the atomization zone through the downstream end of the reaction zone, comprising the following steps:
(a) introducing into the burner zone under con-ditions of high turbulence (i) at at least one point of entry, oxygen at a total inlet pressure of about 20 psig to about 40 psig, (ii) at at least one other, but separate, point of entry, hydrogen and about 1 to about 50 parts by weight of another fuel gas per part by weight of hydrogen at a total inlet pressure of about 20 psig to about 40 psig, and 33.
(iii) at at least one of the points of entry set forth in (i) and (ii), steam at a total inlet pressure of about 20 psig to about 40 psig wherein the ratio of oxygen to steam is about 0.5 part by weight to about 10 parts by weight of oxygen per part by weight of steam and wherein pressure, rate of flow, temperature, and turbulence are maintained at sufficient levels to provide an essentially homogeneous gas mixture and essentially complete combustion thereof, and wherein the burner zone outlet temperature is in the range of about 1900°C. to about 2400°C. and the burner zone pressure is in the range of about 20 psig to about 40 psig, and igniting said gas mixture to form together with the steam a mixture of combustion gases;
(b) introducing the gases from the burner zone into the mixing zone in a direction about perpendicular to the axis through at least one constricted throat section, the velocity of the gases in the throat section being subsonic and the constriction being of such cross-section relative to the burner zone that the subsonic velocity of the gases accelerates when passing therethrough and approaches sonic velocity, wherein the mixing zone is constructed in such a manner that the gases expand on entry into said mixing zone;
(c) introducing crude oil into the upstream end of the atomization zone in a downstream direction at an inlet pressure of about 500 psig to about 800 psig and in the shape of a right circular cone, wherein the base of the cone is downstream from the apex of the cone, the axis of the cone is essentially parallel to the axis of the mixing 34.
and reaction zones, the apex angle of the cone is about 15 degrees to about 140 degrees, and the downstream portion of the cone is comprised of droplets of crude oil having a size of less than 50 microns;
(d) passing the droplets of crude oil from the downstream end of the atomization zone into the gases at the upstream end of the mixing zone in a ratio of about 0.75 to about 1 part by weight of crude oil per part by weight of gases and in such a manner that essentially all of the crude oil vaporizes into the gases in the mixing zone;
(e) passing the effluent from the mixing zone into the reaction zone wherein the outlet temperature of the reaction zone is in the range of about 800°C. to about 1000°C., the pressure in the reaction zone is in the range of about 10 psig to about 25 psig, and the residence time of the crude oil and the products thereof in the mixing zone and the reaction zone combined is about 10 to about 40 milliseconds;
(f) passing the effluent from the reaction zone into a quenching zone having a sufficiently low temperature to stop the reaction essentially instantaneously; and (g) recovering the effluent from the quenching zone.
(a) introducing into the burner zone under con-ditions of high turbulence (i) at at least one point of entry, oxygen at a total inlet pressure of about 20 psig to about 40 psig, (ii) at at least one other, but separate, point of entry, hydrogen and about 1 to about 50 parts by weight of another fuel gas per part by weight of hydrogen at a total inlet pressure of about 20 psig to about 40 psig, and 33.
(iii) at at least one of the points of entry set forth in (i) and (ii), steam at a total inlet pressure of about 20 psig to about 40 psig wherein the ratio of oxygen to steam is about 0.5 part by weight to about 10 parts by weight of oxygen per part by weight of steam and wherein pressure, rate of flow, temperature, and turbulence are maintained at sufficient levels to provide an essentially homogeneous gas mixture and essentially complete combustion thereof, and wherein the burner zone outlet temperature is in the range of about 1900°C. to about 2400°C. and the burner zone pressure is in the range of about 20 psig to about 40 psig, and igniting said gas mixture to form together with the steam a mixture of combustion gases;
(b) introducing the gases from the burner zone into the mixing zone in a direction about perpendicular to the axis through at least one constricted throat section, the velocity of the gases in the throat section being subsonic and the constriction being of such cross-section relative to the burner zone that the subsonic velocity of the gases accelerates when passing therethrough and approaches sonic velocity, wherein the mixing zone is constructed in such a manner that the gases expand on entry into said mixing zone;
(c) introducing crude oil into the upstream end of the atomization zone in a downstream direction at an inlet pressure of about 500 psig to about 800 psig and in the shape of a right circular cone, wherein the base of the cone is downstream from the apex of the cone, the axis of the cone is essentially parallel to the axis of the mixing 34.
and reaction zones, the apex angle of the cone is about 15 degrees to about 140 degrees, and the downstream portion of the cone is comprised of droplets of crude oil having a size of less than 50 microns;
(d) passing the droplets of crude oil from the downstream end of the atomization zone into the gases at the upstream end of the mixing zone in a ratio of about 0.75 to about 1 part by weight of crude oil per part by weight of gases and in such a manner that essentially all of the crude oil vaporizes into the gases in the mixing zone;
(e) passing the effluent from the mixing zone into the reaction zone wherein the outlet temperature of the reaction zone is in the range of about 800°C. to about 1000°C., the pressure in the reaction zone is in the range of about 10 psig to about 25 psig, and the residence time of the crude oil and the products thereof in the mixing zone and the reaction zone combined is about 10 to about 40 milliseconds;
(f) passing the effluent from the reaction zone into a quenching zone having a sufficiently low temperature to stop the reaction essentially instantaneously; and (g) recovering the effluent from the quenching zone.
17. The process defined in claim 16 wherein the viscosity of the crude prior to vaporization is below about 1.25 centipoise.
18. The process defined in claim 16 wherein the direction in step (b) is about +20° to about -45°.
35.
35.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US54746975A | 1975-02-06 | 1975-02-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1047543A true CA1047543A (en) | 1979-01-30 |
Family
ID=24184746
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA242,995A Expired CA1047543A (en) | 1975-02-06 | 1976-01-06 | Process for cracking crude oil |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS51103106A (en) |
| BE (1) | BE838290A (en) |
| CA (1) | CA1047543A (en) |
| DE (1) | DE2604392A1 (en) |
| FR (1) | FR2333851A1 (en) |
| GB (1) | GB1529738A (en) |
| IT (1) | IT1054843B (en) |
| NL (1) | NL7601183A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2463800A1 (en) * | 1979-08-23 | 1981-02-27 | Algas Recources Ltd | Cracking hydrocarbon feeds to produce ethylene and synthesis gas - using gas filmed combustor, reactor and quench zone |
| US4256565A (en) * | 1979-11-13 | 1981-03-17 | Rockwell International Corporation | Method of producing olefins from hydrocarbons |
| JPS601138A (en) * | 1983-06-17 | 1985-01-07 | Mitsubishi Heavy Ind Ltd | Thermal cracking process for selective production of olefin and aromatic hydrocarbon from hydrocarbon |
| CA1266059A (en) * | 1983-10-31 | 1990-02-20 | David Milks | Control acr product yields by adjustment of severity variables |
| WO2022220996A1 (en) * | 2021-04-16 | 2022-10-20 | Exxonmobil Chemical Patents Inc. | Processes and systems for analyzing a sample separated from a steam cracker effluent |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1186454A (en) * | 1956-11-10 | 1959-08-25 | Koppers Gmbh Heinrich | Process for the production of precious gaseous hydrocarbons |
| FR1235328A (en) * | 1957-09-03 | 1960-07-08 | Huber Corp J M | Process and device for the production of carbon black |
| CA1032561A (en) * | 1973-07-09 | 1978-06-06 | Gerard R. Kamm | Process for cracking crude oil |
-
1976
- 1976-01-06 CA CA242,995A patent/CA1047543A/en not_active Expired
- 1976-02-05 IT IT1993976A patent/IT1054843B/en active
- 1976-02-05 FR FR7603225A patent/FR2333851A1/en not_active Withdrawn
- 1976-02-05 NL NL7601183A patent/NL7601183A/en not_active Application Discontinuation
- 1976-02-05 GB GB449276A patent/GB1529738A/en not_active Expired
- 1976-02-05 JP JP1089476A patent/JPS51103106A/en active Pending
- 1976-02-05 BE BE164109A patent/BE838290A/en not_active IP Right Cessation
- 1976-02-05 DE DE19762604392 patent/DE2604392A1/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| GB1529738A (en) | 1978-10-25 |
| DE2604392A1 (en) | 1976-08-19 |
| JPS51103106A (en) | 1976-09-11 |
| NL7601183A (en) | 1976-08-10 |
| BE838290A (en) | 1976-08-05 |
| IT1054843B (en) | 1981-11-30 |
| FR2333851A1 (en) | 1977-07-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US2809104A (en) | Gasification of liquid fuels | |
| US5254325A (en) | Process and apparatus for preparing carbon black | |
| US4444697A (en) | Method and apparatus for cooling a cracked gas stream | |
| US2767233A (en) | Thermal transformation of hydrocarbons | |
| CA1116114A (en) | Process for the thermal cracking of hydrocarbons | |
| Longwell et al. | High temperature reaction rates in hydrocarbon combustion | |
| US3408417A (en) | Thermal cracking method of hydrocarbons | |
| US4256565A (en) | Method of producing olefins from hydrocarbons | |
| KR100480536B1 (en) | Method and apparatus for producing a single coherent gas jet | |
| US5120582A (en) | Maximum combustion energy conversion air fuel internal burner | |
| US2971822A (en) | Process for producing carbon black | |
| US2572338A (en) | Autothermic cracking reactor | |
| US4088741A (en) | Carbon black process | |
| US2722553A (en) | Partial oxidation of hydrocarbons | |
| CA1293851C (en) | Process and apparatus for contacting at least two gaseous compounds which react in particular at high temperature | |
| US3498753A (en) | Apparatus for thermal cracking of hydrocarbon | |
| US3079236A (en) | Manufacture of carbon black | |
| US3222136A (en) | Carbon black apparatus | |
| US4775314A (en) | Coal gasification burner | |
| US2934410A (en) | Two-stage burner apparatus | |
| CA1047543A (en) | Process for cracking crude oil | |
| US2989380A (en) | Apparatus for carrying out chemical reactions | |
| NZ211695A (en) | Process for the production of synthesis gas | |
| US3988478A (en) | Carbon black | |
| US4244684A (en) | Method for controlling corrosion in thermal vapor injection gases |