US2273298A

US2273298A - Treatment of hydrocarbons

Info

Publication number: US2273298A
Application number: US231298A
Authority: US
Inventors: Szayna Antoni
Original assignee: ALBERT CHESTER TRAVIS
Current assignee: ALBERT CHESTER TRAVIS
Priority date: 1938-09-23
Filing date: 1938-09-23
Publication date: 1942-02-17
Anticipated expiration: 1959-02-17

Description

Feb. 17, 1942. A. szAYNA TREATMENT OF HYDRCARBONS Original Filed Aug, 6, 1936 N lIJ NIPII .0 R. Qn.

mnentor Patented Feb. 17, 1942 TREATMENT F HYDRV'OCABBONS Antoni Szayna, Brooklyn, N. Y., assixnor to Albert Chester Travis, New York, N. Y.

Continuation of application Serial No. 94,578, August 6, 1936. This application September 23, 1938,' Serial No. 231,298

4 Claims.

f This invention relates to the processing of de rivative hydrocarbon products of crude pretroleum, shale oil, coal tar or natural gases and more particularly to the treating and reforming of such of the foregoing products as are in their unfinished state unsuitable for use as motor fuel because of the low volatility and anti-knock value, poor color and odor, and the presence of elementary sulphur, corrosive organic sulphur compounds, mercaptans, and gums, to thereby render such products suitable for use as motor fuel,

This invention is best illustrated by its application to the processing of so-called pressure distillate, a derivative hydrocarbon product of crude petroleum, produced by the cracking of -crude petroleum, which distillate in its unfinished, that is, chemically untreated state is generally not suitable for immediate use as motor fuel. Such uniinished distillate is most frequently high in elementary sulphur, hydrogen sulphide, mercaptans and gums, contains corrosive organic sulphur compounds, and is of unpleasant odor and 'poor color.

It is to be understood, however, that derivative hydrocarbon products such as are contemplated herein are made up of hydrocarbons boiling within a range of from about 70 F. to about 700 F. or, in general, hydrocarbons Whose molecules have in the main not more than sixteen (16) carbon atoms per molecule. Such products will include hydrocarbons forming light or heavy naphtha, kerosene or light gas oil fractions which in their unfinished state are unsuited -for use as motor fuel, not only because of the features previously referred to, but particularly because of their low volatility.

The prior` art teaches that it is customary to separate the gasoline fraction from the heavier fractions of the distillate and to subject these heavier fractions` such as, for example, the naphtha, to a mild cracking or reforming operation productive of the lighter gasoline. This gasoline resulting fromv the naphtha reforming operation must then be chemically treated to eliminate corrosive sulphur and sulphur compounds, hydrogen sulphide, mercaptans and gums, improve the color and'reduce the tendency to gum formation.

This separate reforming and treating of the naphtha or heavier fractions of the distillate to obtain an increased yield of finished, more volatile gasoline suitable for use as motor fuel is an economically unsound and wasteful operation.

It is an object of this invention to perform as a substantially unitary operation the treating and reforming of derivative hydrocarbon products of crude petroleum,shale oil, coal tar or natural gases to render such products suitable for use as motor fuel.

It is an other object of this invention to reduce the sulphur and gum content and improve the color and odorl of derivative hydrocarbon products of crude petroleum, shale oil, coal tar or natural gases and in the same operation by which vthe foregoing results are accomplished, effect an increase in the percentage of lower boiling hydrocarbons in such products.

It is still another object of this invention to produce from a derivative hydrocarbon product of crude petroleum, shale oil, coal tar or natural gases, a motor fuel having a higher lead response or susceptibility than a motor fuel produced from the application to such a product of the separate reforming and treating processes heretofore known to the art.A

It is another object of this invention to effect the unitary treating and reforming of unfinished derivative hydrocarbon products of crude petroleum, shale oil, coal tar or natural gases, such as, for example, naphtha and/or kerosene, to produce thereby a finished motor fuel which is stable as to color and gums, of desired volatility and octane number, of improved color, which is doctor stable in that it remains doctor sweet on heating or distillation, is free of elementary sulphur, hydrogen sulphide and mercaptans, and generally is low in sulphur and gum content.

It is a further object of this invention to provide a novel process for accomplishing the foregoing and related results which is of great utilit simple in operation and of proved economy.

Other and further objects of this invention will appear from the following description and appended claims.

The accompanying drawing which forms part of the instant specification and is to be read in conjunction therewith is a diagrammatic showing in elevation of one form of apparatus capable of carrying out the process of this invention.

In general, when processing pressure distillate, for example, the distillate, preferably in admixture with small quantities of hydrogen is heated to a cracking temperature sufiicient to vaporize the distillate and initiate a mild cracking, or reforming, of its heavier hydrocarbons. The mixture of hot distillate vapors and hydrogen, together with some water or steam if desired, is passed under pressure through beds of specially prepared inorganic materials in a series of insulated chambers or reaction zones where the treating and reforming of the distillate vapors is carried to its conclusion. For convenience, the mixture of distillate vapors, hydrogen, and Water or steam, if the latter ls employed, will be termed, hereinafter, the reactant.

The specially prepared inorganic material, or contactor, as it will be hereinafter termed, may be metallic iron, nickel, cobalt or copper, or oxides of these metals, or suitable combinations of these metals, or of their oxides, or of these metals and their oxides, preferably deposited on particles of inert refractory carriers such as porcelain, pumice, bauxite, silica gel or carborundum or combinations of such carriers. These carriers may be admixed with small quantities of metals such as aluminum, chromium, thorium, or magnesium or suitable mixtures thereof.

These contactors have the capacity of irreversibly absorbing the sulphur from sulphur compounds in the reactant, thus producing a reactant low in sulphur and gum content and especially free of elementary sulphur, hydrogen sulphide and mercaptans. The foregoing contaotors do not interfere with the mild cracking, or reforming of the reactant, but on the contrary, at or above a cracking temperature and in the presence of small quantities of hydrogen such contactors assist the cracking reaction in the formation of lighter hydrocarbons condensable to motor fuels of high quality, good color, and of low gum and sulphur content. The previously described contactors do not act as catalysts as such term is generally understood since they do not reversibly absorb sulphur.. After passing a limited amount of the reactant over the contactor, the contactor must be regenerated with hot air, ue gas, or steam, or suitable mixtures thereof. The regenerated contactor is then activated with hydrogen to obtain a contactor of the desired special state of activity. A catalytic process as distinguished from the present process produces a nished motor fuel contaminated with hydrogen sulphide which must subsequently be removed.

It is necessary that the contactor employed be in a special state of activity which is less than. its maximum state of hydrogenating activity. In general, a contactor is employed whose special state of activity is that which will eiect the desired desulphurization and the desired hydrogenation of the gum forming constituents of the reactant without undesirable hydrogenation of its valuable aromatics.

The hot reactant first enters a reaction chamber containing relatively leastactive contactor and then enters a reaction chamber containing contactor in a relatively higher state of activity while one or more chambers containing exhausted contactor are cut out of the system for regeneration and activation of the contactor.

The chamber into which the reactant first enters contains partially exhausted contactor which will eiect the removal of the majority of the more 4easily removable sulphur and in this chamber most of the cracking or reforming will take place. The reactant issuing from the first chamber enters a second chamber containing contactor of a higher state of activity. This higher state of activity is preferably that which exhibits, first, a pronounced desulphurizing action on the more dicultly removable sulphur compounds, and second, a relatively low hydrogenating action on the valuable aromatic hydrocarbons of the reactant.

It is known to those skilled in the art that nickel in a finely divided state has the capacity to decompose highly heated hydrocarbons into their elements. This capacity is counteracted in the practice of this invention by first, employing a contactor such as nickel in a partially exhausted, poisoned or impure state and second, by the presence of hydrogen in the reactant.

Preferably, the system should include at least three reaction chambers, although it is possible to use two or only one, though in the latter case batch operation must be practiced. When three chambers are employed, although any greater number may be employed if desired, one is cut out for regeneration and activation of the contactor while the reactant undergoes treating and reforming in the remaining two. When the least active contactor in one of the two chambers on stream becomes too exhausted to accomplish the desired treatment in this stage, the ow is changed so that the reactant is first fed into the second chamber containing partially exhausted contactor and from there into the third chamber containing freshly regenerated and activated contactor.

The regeneration and activation of the contactor is carried on in situ by rst steaming out the reaction chamber to remove residual liquid, slop, etc., then removing the sulphur from the contactor with hot air, iiue gas, or steam, or mixtures at the proper temperature and finally activating the hot regenerated contactor to the desired state of activity with a stream of hydrogen.

It is essential that the reactant be at a temperature such that a mild degree of cracking or reforming of the heavier hydrocarbons of the reactant takes place simultaneously with the treating action for sulphur absorption, gum removal, color improvement and the formation of a stable doctor sweet motor fuel.

The reactant on issuing from the final reaction chamber is subjected to absorption and fractionation operations for the separation and recovery of the hydrogen and for the recovery of treated motor fuel of the desired end point, respectively. The treated motor fuel may be subjected to an acid and caustic wash to remove nitrogen bases and phenols and to secure the nal improvement in color if the source of the distillate renders this necessary.

Referring now more particularly to the drawing, liquid to be processed iiows through the pipe I and is charged by a pump 2 controlled by a flow controller diagrammatically shown at 3, serially through a pipe 4, vapor heat exchanger 5, pipe 6, liquid heat exchanger 1, pipe 8, vapor heat exchanger 9, and pipe I0 into a convection heating coil II positioned in a combustion gas passageway I2 of a tube still I3 provided with burners I4 and having the combustion gas discharging through a duct I5. The coil II is serially connected by pipe I6 with a heating coil I1 positioned in a hotter portion of the convection gas passageway. 'I'he coil I'I is connected by a pipe I8 with a radiantly heated coil I9 whose discharge end is connected to a high pressure vapor transfer line and inlet header 20.

'Ihe header 20 is connected by means of a plurality of branch lines 2|, 23 and 25 controlled respectively by valves 22, 24 and 26 to the top of a plurality of

reaction chambers

21, 28 and 29, respectively although this by way of example only since the header may be connected through branches (not shown) to the bottoms of the reaction chambers. Although but three reaction chambers are shown and described, it is to be understood that this is by way of example only and others may be added if necessary.

The reaction chambers are provided with connections permitting vapors to be processed to pass through the chambers in series or, parallel ow as desired.

For obtaining parallel operation, the bottoms of

reaction chambers

21, 28 and 29 are connected by means of the pipes 32, 34 and 36, respectively, having valves 83, 35 and 31, respectively, to a pipe, or high pressure outlet header 38 connecting the chambers with absorption and fractionation apparatus, as will be more fully described hereinafter. I

For obtaining series loperation, the bottoms of

reaction chambers

21, 28 and 29 are4 connected The outlet header pipe 38 is connected serially through the heat exchanger 9, pipe 52, heat exchanger 53, pipe 54, condenser 55 and pipe 56 to a high pressure gas separator 58. Cooling liquid inlet and exit pipes 59 and 60, respectively. are connected to the condenser 55.

Separator 58 is provided with a drain pipe 6| controlled by a valve 62, and with suitable baiiles 63 for obtaining separation of water from distillate condensate. arator 58 to a header 66 provided with a drain valve 61. A pipe 68 is connected to the header 66 for discharging water, and is provided with a trap 69.

An absorber connected to the top of separator 50 contains a spray nozzle 1|, or other suitable absorption oil injection device. A tail gas discharge pipe 12 havingpressureycontrol valves 13 and 14 connects absorber 10 with a hydrogen storage tank 15. A portion of the hydrogen flowing through the pipe 12 may be diverted through a pipe 16 to a compressor (not shown) by which fresh and recycle hydrogen may be fed through pipe 3| controlled by valve 30 into distillate owing through pipe 4. The pipe 12 contains a pressure responsive valve governing a flow control device controlling pressure control valve 14.

The separator 58 is serially connected by a condensate discharge pipe 11, having a valve 18 controlled by liquid level control device 19, vapor heat exchanger 53 and pipe 80 to a fractionating tower 8|.

Fractionating tower 8| is provided with a drain pipe 89 controlled by a blowdown valve 80. The bottom of the fractionator is serially connected by a pipe 9| having a pump 92, controlled by a flow control device 93, through pipe 94, heat exchanger 1, pipe 95, cooler 96, pipe 91, to a lean absorption oil supply pipe 98, having a valve 99 and flow meter |00a, connected to the spray nozzle 1| of absorber 10.

The separator I|0 is provided with a drain pipe contrclled by a valve ||2 and with suitable bales ||3. Pipes ||4 and ||5 connect the separator with a water header |1 having a drain valve ||6. A pipe ||8 is connected to the header ||1 for discharging water.

The separator ||0 is serially connected by pipe ||9, pump |20, pipe |2| and reflux pipe |23 to the top of fractionator 8|. A flow control device |22 connectedV between pump |20 and pipe |2| controls the rate of pump discharge. The reux return pipe |23 contains a valve |24 operated by a suitable device |25 connected to respond to the temperature at the top of the fractionating tower.

The pipe |2| is also connected with a pipe |26 having a valve |21 controlled by a liquid level control device |28 in the separator ||0 for delivering the net treated distillate to storage.

The apparatus for the regeneration and activation of the contactor in the

reaction chambers

reaction chamers

21, 28 and 29 by means of the pipes |42, |44 and |46, respectively, having valves |43, and |41, respectively and is connected to the bottoms `of the

reaction chambers

Av high pressure steam pipe |56 having a throttle valve |64 and one way check valve |65 is connected to transfer pipe 20 for adding steam to the .reactant in such quantities as may be deemed desirable.

The storage tank 15 containing recycle hydrogen for the activation of the contactor in the various chambers is connected to the utility ring header |31 by means of a pipe |13 having a pressure control valve |14 and throttle valveA |15.

The following is an example of the operation'of this invention:

A heavy naphtha from a high sulphur California crude containing about 0.6% sulphur, having an octane number of about 30, and boiling from about 300 F. up to about 450 F. was fed to the system through the pipe and charged by the pump 2 serially through the pipe 4, heat exchanger 5, pipe 6, heat exchanger 1, pipe 8, heat exchanger 9 and pipe i0 to the convection heating section of the tube still i3. Hydrogen in ture, or reactant, thus formed heated in convection sections and |1 and radiant heating section I9 of the tube still i3 to va temperature of about 890 F., sulcient to initiate a cracking or reforming of the heavier hydrocarbons of the naphtha into lighter, more volatile gasoline hydrocarbons.

The reactant on issuing from the tube still 3 at the cracking temperature flowed serially through the pipe 20 and pipe 2|, valve 22 being open, into the reaction chamber 21 containing about three tons of partially exhausted nickel contactor deposited on pumice. The temperature of the reactant during passage through the insulated chamber 21 was preferably maintained between about 890 F. and about 860 F. The reactant on issuing from the chamber through the pipe 39, valve 40 being open and valves 33, |49, 41 and ,|43 in pipes 32, |48, 46 and |42, respectively, being closed, flowed from thence serially through the pipe 45 and the pipe 48, valve 49 being opened, into the top of reaction chamber 28, valves |5|, 42, |45 and 24 in pipes |50, 4|, |44 and 23 respectively being closed.

The reactant in the chamber 28 was preferably maintained at a temperature of from about 850 F. to 800 F. during its passage over a bed of more active contactor comprising about three tons of metallic nickel deposited on pumice, and on issuing through the pipe 34, valve 35 being opened, entered the vapor line 38.

The treated and reformed reactant passes serially through the pipe 38, heat exchanger 9, pipe 52, heat exchanger 53, pipe 54, condenser 55, and pipe 56 into the gas separator 58 where a separation of condensate from uncondensed gases is eiected. The separator 58 and the absorber 10 connected thereto were operated substantially at the pressure existing in the reaction chambers, namely 200 lbs. per square inch. The uncondensed gases consisting primarily of hydrogen diluted with some gas from the cracking or reforming operation amounting to, roughly, about 4% by weight of the naphtha to be treated is scrubbed in the absorber with lean oil injected into the absorber through the spray nozzle 1|. The hydrogen was discharged through the pipe 12 and valves 13 and 14 into the storage tank 15, a portion of the hydrogen being diverted through the pipe 12 to pipe 16 to suitable compressors (not shown) The condensate collecting in the separator 58 on being freed of water through the water drawoi pipe 68 passed through pipe 11 at a reduced substantially atmospheric pressure effected by the valve 18, through the heat exchanger 53 and through pipe 80 to the fractionating tower 8|.

Steam supplied through the pipe 82 may be superheated in the tubes 83 of the top still |3 and passed through the line 85, the valve 86 being open, into the bottom of the fractionating tower 8| through the perforated pipe 88 in such amount as may be desired to facilitate the fractionation and stripping of the bottoms. The flow of this steam may be determined by the ow meter 81. The connection 84 may be provided if steam from the line 82 is desired for other purposes.

The temperature and the reflux) ratio in the tower 8| was controlled so as to permit the taking overhead of cracking gases and a treated gasoline boiling from about 90 F. to about 400 F., which gas vapor mixture passes serially through pipe |04, heat exchanger S, pipe |05, condenser |06 and pipe |09 into the gas separator and reflux tank ||0. A portion of the treated gasoline accumulating in the tank |0 is returned through the pipes ||9, |2| and |23 as reflux to the fractionating tower by the pump |20. The net treated gasoline removed from the system through the pipe |26 was doctor" sweet, doctor and color stable, was free of elementaryl sulphur, mercaptans and hydrogen sulphide, and a sulphur content of only 0.05%, was of good color and odor and the octane numbers had been improved from the original 30 to approximately 69. In addition, the lead response, or susceptibility, of this gasoline was better than that of gasoline produced by conventional treating and reforming processes.

The tail gas from the separator |I0 was discharged from the system at reduced pressure Athrough pipe |29 and valve |30 and water separated from the gasoline drawn from the accumulator through the pipe ||8.

Hydrocarbons higher boiling than are desired in the finished gasoline are withdrawn as a liquid from the bottom of the fractionator 8| through the pipe 8| and after cooling discharged from the system through the pipe |80, a portion of the cooled liquid being returned, however, through the pipe 98 to the spray nozzle 1| of the absorber 10 as lean absorption oil.

The chamber 29 contains poisoned or exhausted contactor to be regenerated and activated. Following regeneration and activation of the contactor, the chamber 29 will be cut into the system in place of chamber 21 and the reactant will then be passed through the reaction chamber 28 containing least active contactor and then through the reaction chamber 29 which latter will contain contactor of a higher degree of activity. The substitution of the chamber 29 for the chamber 21 and the change of the ow of the vapors through the chambers 28 and 21 may be eiected by obvious manipulation of the valves shown.

In regenerating the contactor in the chamber 29, air fed to the compressor |32 through the pipe 63| was heated in the heater |35 and then passed through the pipe |36 into the utility ring header |31. Live steam from pipe |56 was admixed with the air by opening the valve |58 in the pipe |51 while additional steam was passed through the pipe |60 and branch pipe |6| into the utility ring header |31 by opening the valve |62, valve |64 being closed. The mixture of air and steam at a temperature of about 750 F. entered the chamber 29 through the pipe |46, passed through the bed of contactor in the chamber 29 and then discharged through the pipe |52 into the header |31 from which it was discharged through the pipe |54, valve |55 being open. An initial steaming out of the reaction chamber 29 prior to regeneration was carried out to discharge the slop in the chamber 29 into the header |31 through pipe |52 and from thence through the pipe |66 in which valve |61 is opened into the cooling coil |68 of the cooler |69. This cooled slop or material washed from the contactor was discharged from the cooler through the pipe |10. The iiuid medium used for regeneration decomposes the nickel sulphide to nickel oxide and this regenerating material is passed over the contactor for a period of time sucient to accoml plish the desired result. Some sulphur is left in the contactor.

The activation of the regenerated contactor relatively high temperature of from 500 to 800 F.

is reduced by the hydrogen to the selected state of activity. The flow of hydrogen is discontinued When this state is reached which may be determined either as the result of experience gained from previous runs or by laboratory tests of the activated contactor.

It is to be understood that the operating conditions herein recited are by way of example only and are not to be considered as limiting since obviously Various changes in the conditions of time, temperature and pressure may be made, depending upon the sulphur content of the material being charged and its general characteristics necessarily determining the operating conditions to be employed for achieving the desired degree of reforming or cracking of the heavier hydrocarbons and treating of the charging stock.

The following are examples of operating factors for the practice of this process: Temperature range: 750 F. to 1000o F.

Pressure: Atmospheric to 1400 lbs. per sq. in.

gage.

Amount of hydrogen: Oto 5% by weight of charging stock.

Contactor: 1% to 25% by weight of charging' stock. Water (steam) 0% to 5% by weight of charging stock.

Degree of cracking: The amount of cracking gasl formed should in general not exceed more than 8% by weight of the charging stock. Regeneration: Air, steam, nue gas or mixtures at a temperature of from 500 to 1000 F. Activation: Hydrogen reacting with contactor at 500 F'. to 800 F.

It will be observed that the objects of this invention have been accomplished. There has been provided a process by which the simultaneous treating and reforming of a derivative hydrocarbon product may be carried out to produce a treated liquid suitable for use as motor fuel. There has been provided a process by which the volatility and octane number and the lead susceptibility of a relatively wide boiling range hy drocarbon fraction may be increased simultaneously with the removal of all elementary sulphur, hydrogen sulphide and mercaptans, and a substantial decrease of the other sulphur compounds. There has been provided a process by which a motor fuel of suitable volatility may be produced by the unitary treating and reforming of a hydrocarbon fraction such as naphtha or kerosene, which motor fuel is of improved color, is low in sulphur and gum, is non-corrosive, is doctor sweet, and is doctor stable in that it does not become sour on reheating or rerunning.

It will be observed that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is Within the scope of the following claims. It is further obvious that Various changes may be made in details Within the scope of these claims without departing from the spirit of this invention. It is, therefore, to be understood that this invention is not to be limited to the specific details shown and described. This application is a continuation of application Serial No. 94,578, led August 6, 1936.

What I claim is:

1. A process for treating hydrocarbon oils to produce therefrom motor fuel substantially free of sulfur Which comprises heating said oil to a cracking temperature, passing said heated oil in vapor phase inadmixture with l to 5% of hydrogen by Weight through a body of Contact material comprising a metal of the group consisting of iron, nickel, cobalt and copper in a special state of activity wherein its hydrogenating and desulfurizing power is less than maximum throughout said body to effect removal of sulfur from said hydrocarbon oil by absorption of sulfur from said oil in said body, discontinuing the flow of said oil vapor through said body, regenerating said body by removal of sulfur therefrom, controlling said regeneration to effect retention throughout said body of a minor proportion of sulfur in combination with said metal and effect regeneration of said body to said special state of activity.

2. A process in accordance with claim 1 wherein regeneration is effected by the passage through said body of an oxygen-containing gas to effect oxidation of compounds of said metal and sulfur and removal of sulfur from said body in a gaseous product, the reaction of said compounds and said oxygen is controlled to effect retention throughout said body of a minor proportion of sulfur in combination with said metal, passage of said oxygen-containing gas through said body is discontinued, and reduction of oxide reaction products in said body is effected by the passage therethrough of a hydrogen-containing gas.

3. A process in accordance with claim 1 wherein said oil is heated to a temperature of 750 to 1000 F.

4. A process in accordance with claim 1 wherein regeneration of said body is effected at 500 to 1000 F.

ANTONI SZAYNA.