US1933108A - Art of and apparatus for converting hydrocarbons - Google Patents

Description

Oct. 31, "1933. w GOMQRY 1,933,108

ART OF AND APPARATUS FOR CONVERTING HYDROCARBONS Filed Aug. 15, 1950 2 Sheets-Sheet l WEN /28 hi/EATER 7 PAT/M34725? Oct. 31, 19 w. GOMORY 1,933,108

ART OF AND APPARATUS FOR CONVERTING HYDROCARBONS Filed Aug. 13, 1930 Z'Sheecs-Sheet 2 wrgwrw;

Patented Oct. 31, 1933 ART OF AND APPARATUS FOR CONVERT- ING HYDROCARBONS William L. Gomory, Paris, France, assignor to Standard Oil Development Company, a corporation of Delaware Application August 13,

1930, Serial No. 475,099,

and in Great Britain July 15, 1930 6 Claims.

This invention relates to an improved process and apparatus for the treatment of hydrocarbons in the presence of hydrogen or hydrogen-containing gas.

According to my invention, the oil is subjected to vaporization at atmospheric or super atmospheric pressure in a vaporizing zone, from which there is recovered a reflux condensate that is subjected to cracking conditions of temperature, pressure and time in a heating and cracking zone, in the presence of hydrogen or hydrogen-containing gas or gas capable of liberating hydrogen, or in the presence of substances capable of liberating hydrogen or hydrogen-containing gas or gaseous hydrocarbons, and in the presence or absence of catalysts. All of these alternatives, either singly or in any desired combination will be hereinafter referred to as hydrogen. Such heating and cracking zone may consist of a heating coil arranged in conjunction with one or more conversion chambers; or it may consist of a coil which forms a combined heating and cracking zone. The products from the heating and cracking zone are discharged into the vaporizing zone, from which the vapours are removed and the residue withdrawn. The oil, before being subjected to vaporization as above mentioned, may be advantageously heated while passing it through a heating zone, for example a coil, under pressure.

The residue obtained in the evaporator is subjected to cracking conditions of temperature, pressure and time in the heating and cracking zone or in a separate apparatus in the presence of hydrogen. The residue is introduced either wholly or partly to the inlet of the heating and cracking zone; or the said residue may be introduced at an intermediate point or points of a coil forming the heating zone or both the heating and the cracking zone; or the residue may be introduced intothe stream of material at the outlet end of the coil. Or the residue may be introduced into the system at two or more of th positions above mentioned.

The reflux condensate from the vaporizing zone may be introduced either wholly or partly into the inlet of the heating and cracking zone; or the said reflux condensate may be introduced at an intermediate point or points of the coil which forms either the heating zone or a combined heating and cracking zone. The reflux condensate may also be introduced into the stream of material at the outlet end of the coil. The reflux condensate may however be introduced into the system at two or more of the positions above mentioned.

In cases where there are separate heating and cracking zones the quantity of residue or of reflux condensate, or of both residue and reflux condensate introduced into the stream of heated oil and hydrogen passing from the heating zone, e. g, a coil or series of coils, to the cracking zone, e. g. one or more conversion chambers, is so regulated that it will control the temperature of the oil in the cracking zone. A further means of effecting such regulation of the temperature, consists in that part of the oil from the coil or series of coils is taken from an intermediate point in such coil or series of coils and is introduced into the stream of heated oil and hydrogen passing from the heating coil or coils into the conversion chamber or chambers.

The temperature of the stream entering the evaporator can be controlled in a similar manner.

In cases where the heating and cracking zone consists of a coil or series of coils only, the quantity of the residue and/or reflux condensate introduced into the stream of products and hydrogen passing from the heating and cracking coil or coils to the evaporator, is so regulated that it will control the temperature of the oil before the same enters into such evaporator, or will control the temperature of the oil in the evaporator. Furthermore part of the oil passing through the coil or coils may be taken from an intermediate point of the coil or coils and introduced into thestream of products passing to the evaporator, in order to regulate the temperature thereof.

The reflux condensate before it is introduced into the heating and cracking zone, is subjected to distillation at atmospheric or super-atmospheric pressure for the purpose of recovering light fractions from the same.

The light vapours recovered from the reflux condensate are introduced into the fractionator or frictionators either separately or together with the vapours obtained in the vaporizing zone. Or if desired such light vapours may be introduced into the vaporizing zone. Moreover the 100 vapours obtained from the reflux condensate may be partly introduced into the vaporizing zone,

e. g. the heavier fractions, and partly into the fractionator or fractionators, e. g. the lighter fractions. Or the said light vapours may be 105 fractionated in a separate fractionator.

The residue removed from the vaporizing zone before further hydrogenation treatment is advantageously subjected to a second vaporization at atmospheric or super-atmospheric pressure, 110

the vapours so obtained being introduced into the first vaporizing zone, the final residue being withdrawn and if desired subjected to further destructive Hydrogenation. The vapours obtained from the residue in the second vaporizing zone may be' introduced into the fractionator or fractionators. The vapours obtained from the residue in the second vaporizing'zone may be separately fractionated or they may be partly introduced into the first vaporizing zone and partly into the fractionator or fractionators receiving the vapours from the evaporator, e g., the heavier and lighter fractions respectively.

In some cases it may be desirable to subject the residue from the first vaporizing zone to a second vaporization at atmospheric or superatmospheric pressure in such a manner as to vaporize all volatile matter contained in the residue, the resulting solid residue being removed and the vapours introduced into the first vaporizing zone or into the fractionators or into both the first vaporizing zone and the fractionators.

The vapours obtained from the residue in the second vaporizing zone are advantageously subjected to fractional condensation, the uncondensed vapours being passed into the first vaporizing zone or into the fractionators, or into both the first vaporizing zone and the fractionators, and the condensed heavier fractions being returned to the system with or without subjecting them to distillation in a still, which may be the still in which the reflux condensate from the first vaporizing zone is re-run.

In all the above forms of my improved process, the vapours may be separated into good-end point gasoline and other valuable fractions by passing them through fractionators and rectifiers provided with controlled cooling, which cooling may be effected either by the feed oil or by means independent thereof.

The reflux condensate obtained in the fractionator or fractionators may be introduced into the vaporizing zone for redistillation.

In cases where the heating and cracking zone consists of separate heating and cracking zones,

the oil may advantageously be conducted through a continuous heated coil and one or more heatinsulated conversion chambers, wherein the oil is subjected to cracking conditions of temperature, pressurc and time in the presence of hydrogen. In such conversion chambers, the material under conversion may be thoroughly agitated during the reaction. Thus the material under conversion may be circulated from the lower part to the upper part or top of the conversion chamber or chambers. Or it may be circulated from the conversion chamber or chambers into the coil and back into the chambers.

The hydrogen under pressure and in heated condition may be introduced into the inlet end of the heating and cracking zone; or it may be introduced at an intermediate point or points of a coil forming the heating zone or both the heating and the cracking zones; or it may be introduced directly into the conversion chamber or chambers. The hydrogen may also be simultaneously introduced into the inlet end of the heating and cracking zone and into the conversion chamber or chambers; or it may be introduced into the coil at various points thereof and into the conversion chamber or chambers.

A uniform super-atmospheric pressure may be maintained in the coil and in the conversion chambers, where'such are employed, or a higher pressure may be maintained in the heating coil than in the conversion chamber or chambers. The pressure in the vaporizing zone may be maintained at a lower value than that in the conversion chamber or chambers, or in the coil or coils in cases where no separate conversion chamber is employed. The pressure in the still, in which the reflux condensate from the first or primary vaporizing zone is re-run, is maintained at a higher value than that in the first vaporizing zone or in the fractlonators. Furthermore a higher pressure is advantageously maintained in the auxiliary or secondary vaporizing zone than in the first or primary vaporizing zone. Generally speaking difi'erent pressure conditions may be maintained in the various parts of the system. Moreover in cases where a coil forms a combined heating and cracking zone, uniform pressure conditions may be maintained in the coil and in the evaporator.

The material under conversion is advantageously subjected to the action of catalysts and/ or substances capable of liberating hydrogen or hydrogen-containing gas or gaseous hydro-carbons in the conversion chamber or chambers or in the coils, or in both the conversion chamber or chambers and in the coils. These materials may be spread on perforated trays or otherwise suitably disposed of in the chambers. Whilst being subjected to the action of catalysts the material under conversion is preferably thoroughly agitated in the conversion chamber or chambers.

Substances capable of liberating hydrogen or hydrogen containing gas or hydrocarbon gases which may be used are for instance: steam and iron, water and alkali metals, naphthenes in the presence of nickel, water and carbide, natural gas, coal gas, hexamethylene in the presence of porous porcelain, etc.

The catalysts and/ or the substances capable of liberating hydrogen or hydrogen containing gas or hydrocarbon gases can be employed in suspension or in colloidal solution and thus circulated through the system together with the material to be treated.

In the above operations the excess hydrogen is separated from the vapours produced and is returned to the system after proper purification.

The not condensed hydrocarbon vapours and gases on their way to the hydrogenating system may be subjected to dissociation in a dissociating 12o furnace, for instance in an electric arc furnace or coil furnace, as it is described in my co-pending application Serial Number 475,102 filed August 13, 1930.

In a preferred form of my improved process 130 the hot products of destructive hydrogenation are introduced without substantial loss of heat into a vaporizing zone in which the introduced charging material is subjected to vaporization together with the hot products of destructive hydrogena- 135 tion and from which the vapours and the residue are separately removed. The residue thus obtained is preferably introduced into a second vaporizing zone wherein it is subjected to a second vaporization. The vapours from the second 140 vaporizing zone can be introduced into the first vaporizing zone. Furthermore the vapours obtained in the second vaporizing zone are subjected to fractional condensation, the uncondensed vapours being passed into the first vaporizing zone 145 or into the fractionator or fractionators or into both the first vaporizing zone and the fractionator or fractionators, the condensed heavier fracwhich the reflux condensate from the first vaporizing zone is re-run.

My said invention comprises a process wherein the oil is subjected to cracking conditions of temperature, pressure and time whilst it is conducted through a continuous heated coil and one or more heat-insulated conversion chambers in the presence of hydrogen the material under conversion being circulated from the lower part to the top or upper part of the conversion chamber or chambers.

The present invention also comprises suitable apparatus for carrying into practice the several forms of my improved process.

In order that the invention may be fully understood reference will be made to the accompanying drawings which illustrate in diagrammatic form with parts in section preferred apparatus for carrying my improved process into practice.

Referring to Figure 1, the oil to be treated is drawn from any convenient source of supply 1 by means of a pump 2 and is forced through line 3 into a heating coil 4 located in a furnace setting 5, the oil then passing through line 6 into an evaporator 7. Valved by-pass lines 90, 91 and 92 are provided in line 3 whereby a regulated amount of feed oil may be sent through cooling coils 8 i and 9 located in the upper parts of the fractionators 10 and 11 respectively and thence through line 12 into line 6. A by-pass line 13 is also provided in line 3 whereby all or part of the feed oil may be passed directly to the evaporator 7 without passing through heating coil 4. A heating coil 14 is provided in the lower portion of evaporator '7. Moreover steam may be injected into the evaporator through spray pipe 15. A cooling coil 16 is provided in the upper portion of the evaporator '7 through which feed oil passing from line 6 to furnace coils 23 may be passed whilst a further cooling coil 17 is provided in the evaporator, so that the cooling may be controlled by means which are independent of the supply of feed oil. Bafile plates 17 are suitably disposed within the evaporator 7 to ensure a thorough intermingling of ascending vapour with descending liquid and the evaporator is advantageously heat insulated. The temperaturemaintained in the evaporator will vary according to the nature of the raw material undergoing treatment. The temperature in the evaporator is so regulated that the fractions which consists mainly of gasoline, naphtha, and kerosene leave the evaporator as vapours, whilst heavier fractions are condensed therein to form reflux condensate and residue. Reflux condensate formed in the evaporator 7 is collected in a pan 18 from which it is withdrawn through line 19 by means of a pump 20. Reflux condensate is forced by reflux pump 21 through line 22 into the inlet of the furnace coils 23 which are located in a suitable furnace setting 24. The furnace coils 23 comprise three pipe sections 25, 26 and 27 which are situated in different positions in the furnace. The pipe section 27 of the furnace coils 23, which may beof larger diameter than the pipe sections 25, 26, may contain suitable hydrogenating catalysts or substances capable of liberating hydrogen or hydrogen-containing gas or gaseous hydrocarbons. The heating coils may advantageously be built up of a series of straight pipes in accordance with standard practice, e. g. with the ends of the pipes extending through the flue walls and suitably connected by headers having apertures provided with removable plugs to permit inspection of the pipes. Feed oil from cooling coil 16 is passed to the inlet of the furnace coils 23 through line 28.

Hydrogen is withdrawn from a suitable source of supply 99 by means of pump 101'and is passed through line 100 into a heating coil 102 which is heated in any suitable manner. Heated hydrogen is passed from the heating coil 102 through line 103 to the inlet end of the furnace coils 23 where it mixes with the oil passing to the coil.

The mixture of heated oil and hydrogen from the furnace coils 23 passes through line 29 and thence through lines 31, 33 and 34 into the thermally insulatedconversion chambers 30, 32 from which the products are withdrawn through lines 95, 96 and 97 to line 98 having pressure reducingvalves 35, 35' and thence pass to the evaporator '7. Valves are suitably disposed in lines 29, 31, 33, 34, 95, 96, and 97, so that the conversion chambers 30, 32may be operated in series or in parallel.

The conversion chambers can be equipped with agitators to keep the material under treatment in vehementsmotion, whilst, if desired, the catalysts may be spread on perforated trays or otherwise suitably disposed within the chambers.

Hydrogen may be passed to an intermediate point of the'furnace coils 23 through line 104 and branch line 105, to the outlet end of the furnace coils 23 through line 104 and to the conversion chambers 30, 32, through line 106 and branch lines 107 and 108 respectively.

Reflux condensate from the evaporator '7 may also be passed by means of pump 36 through line 37 to the limit of the furnace coils 23 and the reflux condensate may be passed to intermediate points of the furnace coils through branch lines 38 and 39 or to the outlet end of the furnace coils through lines 40 and 41,0r through branch-line 22' into the stream of the products passing to the evaporator. Heated oil may be withdrawn from an intermediate point of the furnace coils 23 through line 42 and passed to the conversion chambers through line 29.

Residue is withdrawn from the bottom of the pipes 48 and 40.

Oil undergoing conversion and hydrogenation in the conversion chambers 30, 32 may be agitated during the reaction with the aid of agitators or by a withdrawal of oil therefrom by means of pump 52 through branch lines 49, 50 and line 51 and circulation of such oil through line 53 back to the inlet of the conversion chambers, or through lines 53, 53 and branch lines 53a. 532), from the lower to the upper part of the conversion chambers, or such oil may be circulated through line 45 to the inlet of the furnace coils 23 and thence back to the conversion chambers through line 29.

Vapour and gas from the evaporator 7 pass through line 54, having a pressure control valve 55. into the lower portion of fractionator 11 from the upper portion of which vapour and gas are withdrawn by line 56 to a second fractionator 10. Cooling coils 58 and 59 are provided in the upper portions of the fractionators 10 and 11 respectively to provide cooling means independent of the supply of feed oil, whilst spray pipes 60,

are provided in the lower portion of the frac-' tionators for the injection of steam. The fractionators 10, 11 are heat-insulated. Condensate from the fractionators 10 and 11 is withdrawn through coolers 61 and 62 to storage whilst vapour and gas from 'fractionator 10 is withdrawn through line 63 to a condenser 64. Incondensible gas is separated from condensed vapours in separation drum 109, the condensate flowing through cooler 110 to receiver 93. The incondensible gas is withdrawn from drum 109 by a pump 111 and passed through line 112 to the source of supply 99. Preferably, the incondensible gas, prior to its return to the system is washed with alkali and a hydrocarbon oil in purifiers 114, 114 to remove hydrogen sulphide and other impurities contained in the gas as well as gaseous and low-boiling hydrocarbons.

Preferably the hydrocarbon vapours and gases while being returned to the hydrogenating system are subjected to optimum dissociating conditions.

The dissociation treatment of these gases may be accomplished in a furnace, as shown in my co-pending application Serial Number 475,102. filed August 13, 1930, or an electric arc furnace can be used.

When certain catalysts such as for instance molybdenum and tungsten are. employed it is preferable not to remove the hydrogen sulphide from the gas as hydrogen sulphide increases the activity of these and like catalysts.

Part or all of the condensate from the fractionators 10 and 11 may be passed by pump 80 to the evaporator 7 through line 79.

When it is desired to subject the reflux condensate from evaporator '7 to distillation prior to its return to the furnace coils 23, the reflux condensate is passed through line 65 into the re-run still 66 into which steam is passed through line 6'7 and 'which still can be heated directly or otherwise. Residue from the re-run still 66 is returned to the furnace coils through line 68 and line 3'7 or may be withdrawn from the system through line 68.

Vapour is withdrawn from the re-run still 66 through line 69 to fractionator 11 or all or part of the vapour may be passed through branch pipe 70 to the evaporator 7.

In cases where it is desired to subject the residue from the evaporator 7 to a second vaporization, such residue is withdrawn from the evaporator by pump 72' through lines 71, 72 and branch line 73, into auxiliary evaporators '74 and '75, which are heated by the injection of steam through spray pipes '76 or by direct heat or both. Final residue from the auxiliary evaporators may be withdrawn by pump 94 through line 77 to storage, or it may be returned to the hydrogenation plant through lines 113, and 45 by means of pump 46. Vapour from the auxiliary evaporators 74, is withdrawn through line 78 and is passed either to evaporator 7 through line 81 or into fractionator 11 through branch lines 82, 83. Or if desired, such vapour may be passed through line 84 to a fractional condenser 85 from which uncondensed vapours are returned through lines 86 and 78 either to the evaporator 7 or to the fractionator 11. The fractional condenser 85 is heat insulated and is provided with a cooling coil 85' in the upper part thereof and with a spray pipe 85" for direct steam in the bottom thereof. The condensed heavier'fractions from the fractional condenser 85 are passed'by pump 87 either to the re-run still 66 through line 88 or to the furnace coils 23 through lines 89, 68 and 37.

Referring now to Figure 2 it will be seen that the heating and cracking coils 23 comprise both the heating and the conversion zones and that the conversion chambers have been dispensed with. Generally speaking, however, the operation of the plant is the same as that shown in Figure 1 and like reference numerals have been used to designate like parts of the apparatus. According to the apparatus shown in Figure 2, the treated oil leaving the heating and cracking coils 23 is passed directly to the evaporator '7 through line 29.

In the operation of my improved process, the temperatures and pressures to be used will vary according to the nature of the material undergoing treatment and the products desired. The oil may be heated in the coils to temperatures ranging from 750 to approximately 1500 F. under a pressureof from 50 to 300 atmospheres or more, whilst a temperature of approximately 750 to 850 F. or more and a pressure of 50 to 300 atmospheres or more may be maintained in the conversion chambers. In the operation of my improved process in which the conversion chambers are dispensed with, the oil may be subjected in the heating and cracking coils to temperatures of the order of 750 to 1500 F. at a pressure of 50 to 300 atmospheres or more and atmospheric pressure or a pressure of 5 atmospheres or more can be maintained in the evaporator. Valves are suitably disposed throughout the apparatus to control the flow of oil to the different parts of the system and to enable any desired pressure to be maintained therein.

All the lines conveying oil or gas into the heating coil, to the outlet thereof, and into the conversion chambers, are provided with check valves to prevent the hot products from backing into these lines and all the lines conveying hot oil are heat-insulated.

I claim:-

1. A process for the conversion of hydrocarbon oils which comprises subjecting the oil to'conversion temperatures in a heating and conversion zone under pressure of at least 50 atmospheres in the presence of hydrogen, transferring the hot resulting products directly to a vaporizing and fractionating zone, recovering a reflux condensate therefrom, separately withdrawing and distilling the reflux condensate to remove light fractions therefrom and returning said reflux free from the light fractions directly to said heating and conversion zone.

2. A process according to claim 1, characterized in that the light vapors separated from the reflux condensate are introduced into the fractionating zone.

3. A process for the conversion of hydrocarbon oils into lower boiling fractions which comprises subjecting the fresh oil to a conversion temperature in a heating and conversion zone in the presence of hydrogen under pressure and temperature conditions commonly employed in destructive hydrogenation, transferring the hot product directly to a vaporization and fractionation zone, recovering a vapor fraction containing the desired low boiling constituents, a reflux condensate and a liquid residue therefrom, subjecting the reflux to further vaporization in a separate vaporizing zone, introducing vapors therefrom directly into the first mentioned vaporizing zone, withdrawing a final residue and returning the heavy components of the reflux condensate directly to the heating and conversion zone.

4. A process according to claim 3, characterized in returning the final residue to the heating and conversion zone for further destructive hydrogenation.

5. A process according to claim 3, characterized in that the vapors obtained from the residue in the second vaporizing zone are subjected to fractional condensation, the uncondensed vapors are passed into the first vaporizing and fractionating zone and the condensed heavier fractions are returned to the heating and. conversion zone.

6. In an apparatus for the treatment of hydrocarbon oils, the combination of a heating coil, a reaction chamber and a vaporizer, serially connected, means for introducing hydrogen into the heating coil and the reaction chamber, means for WILLIAM L. GOMORY.

Images