US2030771A - Apparatus for the expansion of hydrocarbons for cracking and distillation - Google Patents

Description

Feb. 11, 1936. c. STILL 2,030,771 APPARATUS FOR THE EXPANSION OF HYDROCARBONS FOR CRACKING AND DISTILLATION Filed July 27, 1933 76] U1 I L/1 I a. mjli E Jlzvevzfon Car! 0522']! Patented Feb. 11, 1935 UNITED STATES APPARATUS FOR THE EXPANSION F HY- DROCARBONS FOR CRACKING AND DIS- TILLATION Carl Still, Recklinghausen, Germany Application July 27, 1933, Serial No. 682,492

In Germany August 5, 1932 4 Claims.- (Cl. 196104) g For carrying out cracking and distillation of liquid hydrocarbons, such as petroleum and petroleum products, tars and tar oils from lignite and pit coals etc., it is usual to heat the oils in heating tubes under pressure to cracking or distillation temperature, and after they have left the heating furnace to expand them, by means of a valve having a suitably loaded valve cone, to low pressure. Such expansion valves when in operation have the drawback that at the moment of expansion of the oils heated under pressure, separation of carbon occurs which settles particularly in the immediate vicinity of the valve opening as a coke-like deposit and thereby chokes thepassage openings of the pressure piping closed by the valve cone and also prevents the free movement of the valve cone.

The object of the invention is to overcome the aforesaid drawbacks and this is done by the valve cone being designed as a member capable of being set in rotation about its centre axis. One formof construction consists, for instance, in that the valve cone is prolonged into a spindle which is in the form of a rotatable shaft and on which the load for pressing the valve on to its seat act's. In this arrangement the shaft may be prolonged to such an extent that its end remote from the valve cone is carried out of the expansion chamber and outside the latter is connected with gearing which maintains the rotation.

In a modified embodiment of the invention, on the valve cone extending in the direction of its centre axis, there is fitted a knife-like scraping device which protrudes slightly into the valve seat and into the connected pressure piping.

According to another embodiment of the invention, the housing forming the expansion chamber, in the region of the valve at the places where the impinging expansion jet tends to produce tightly adhering deposits of carbon, etc., is in the form of a rotating member concentric with the axis of the valve, for instance a circular cylinder, and on the shaft carrying the valve cone scrapers are fitted in such a manner that they constantly scrape the aforesaid parts of the inner sides of the wall of the housing and thereby keep them clear.

Fig. 1 of the drawing shows a vertical axial section of an example of one construction of the apparatus according to the invention;

I Fig. 2 represents mainly a part of the apparatus according to Fig. 1 on an enlarged scale, and

Fig, 3, which is a horizontal section along the line IIIIII of Fig. 2, shows a modification.

In Fig. 1, I denotes a vertical cylindrical housing manhole 4 closed by a lid 5. In the bottom 3 of the housing is an opening 6 adapted to be closed by a stop valve 1. At the bottom part of the housing I there is provided a pipe connection 8 for the supply of liquid hydrocarbons and at the upper part a further pipe connection 9 for the discharge of mainly vaporous expansion products.

At the manhole 5 there is attached the delivery piping I 0 for the supply of the liquid hydrocarbon oils coming from the heating oven 'and which are under high pressure. An extension I I on the pipe III engaging with the member I2 inserted in the housing I serves to secure and exact support on the side opposite the lid 5. Inside the housing I 7 the delivery pipe ID is bent round vertically upwards so as to form an elbow I3, at the upper end of which (see also Fig. 2) the jacket I4 which carries the valve-seat member I5 is fitted. The centre axis of this valve seat I5 is located 1 centrally in the cylindrical housing I. On the valve seat I5 there rests the actual valve cone I6 which is screwed into the lower tubular end of a short shaft I'Iin such a manner as to be exchangeable, and for this purpose its middle part is square, as can be seen in Figs. 1 and 2. The shaft member I1 is guided in a bearing I8 which is firmly connected to the sleeve II by an arm I9 and thereby held exactly in central position.

Th upper part of the shaft member I1 is connected with a shaft 20 in line with its axis by a universal joint 2 I. The upper end of the shaft 20 is connected by a similar universal joint 22 with a further shaft 23 forming the upper prolongation of the valve spindle.

The lower part of this shaft is supported by the bearing 24 which is attached to the housing I by means of the arm 25. The upper part of the shaft 24 is supported and guided by the member 26 of a stufi'ing box fixed in the lid 2. The member 21 of this stuffing box packs the shaft or spindle 23 and seals the opening at this point 'by means of the packing 28. the shaft 23 which protrudes from the lid 2 is The top end of attached a worm wheel 36 which meshes with a worm 3'! which is mounted in a bracket 38 on the lid 2. The drive is provided by a small elecclosed at the top by the lid 2, and having a lateral I tro-motor 39 (likewise supported by the bracket 38) by means of the spur-wheel gearing 40.

The aforesaid vertical shaftZiJ arranged between the universal joints Zl and 22 carries a plurality of arms II to which by means of hinges 42, scrapers 43 are fitted in such a manner that 7 downward axial'prolongation, carries a scraper 44 which in cross-section, as shown in Fig. 3, is formed as knife-like, double-edged member. This scraping knife 3 as may be seen in Fig. 2, protrudes 'a certain distance into the central channel 45 of the valve seat I5 and into the delivery pipe I3, in prolongation of it, and on rotation of the valve cone I 6, serves to keep continuously'clear of deposit this part'of the pas sage-way for the highly compressed oils from the heating oven which is located immediately 7 Le. in the delivery piping l3 and in the valve seat I5 the pressure under which the hydrocar-- in front of the opening closed by the Valve cone I6.

After detachment of the valve cone I6 from the shaft member I'I, made possible by the screwthreaded connection between them, the entire valve assembly I5, I3 (together with the delivery pipe I0, I3)'may be removed through the manhole 4, and, if necessary be replaced.

In operation, the loading exercised by the weight lever 32, 35 on the shaft 23'and; therefore, finally on the valve cone I5, is adjusted to such a value that under the valve cone l5,

bon oils to be treated are to be constantly kept is maintained. When cracking is effected, pressures of about 50 atm. and more, for instance up to approximately 89 atm., may be used.

the intermediate gearing 48.

Now while the oils heated, for instance, to 400 to 500 C., under the aforesaid pressure are delivered through the piping l0, I3 to the valve I5, I5 for the purpose of expansion, the valve cone I6 is kept in continuous rotation by means of the worm gearing 36, 31 by the motor 39 and] The insertion of the two universal joints 2| and 22 ensures that any slight deviations of the centre axis of the valve shaft I? and the upper shaft 23 shall not produce any disadvantageous effects on the free movement of the valve cone both in respect of its vertical movement and also its rotation. The highly compressed oils which are delivered are expanded by the valve I5, I6 for instance to atmospheric pressure, whereby the major part,

thereof is vaporized and a residue of liquid oil constituents and of solid carbon-like constituents are carried over in vapour form. The vapour jets impinge on the inner wall of the housing I approximately at the places which are swept by the scrapers 43. The latter ensure that deposits, 'mainly' of carbon'or viscous pitch-like constituents, are removed. The mixture of expansion products consistingof vapours and mist, is carried off through the pipe connection 9 for further treatment, for instance fractionation. Such non-vaporous constituents which fall by gravity to the bottom of the housing I are collected in the lower space 3 of the housing below'the manhole 4 and are discharged periodically through the opening 6 and the valve I. r

The above-described continuous rotation of the valve cone I6 according to the invention ensures that deposits of carbon are prevented from forming at the outlet of the valve seat I5 and in the immediate vicinity of the valve cone H5, or if they have already been formed, that they are removed. This effect can be further improved by the modification shown in Figs. 2 and 3 by means of the scraper 44, as the latter keeps the inner channel and the delivery pipe I3 free from deposits of carbon. When the liquid which has collected in the bottom part 3 of the housing I has reached such a level that it covers the valve seat I5, the injector-like suction action of the expansion jets can then be utilized to drive, through the lower lateral pipe connection 8 from a storage vessel (not shown in the drawing), any liquid hydrocarbons, for instance fresh raw material or products of the aforesaid fractionation of the expansion products, into the expansion chamber. The cooling and rinsing effect produced by such additional oils on the valve I5, I6 is suited 'to assist in keeping the latter free from deposits of carbon. The oils which are sucked in injectorwise are in this case discharged partially together with the expansionvapour and'mists through the pipe connection 9.

When the interior of the housing I is made sufficiently largev to ensure a marked reduction of the speed of flow of the expansion jet, this alone can cause from the outset a reduction of the deposit of carbon and pitch constituents on the walls of the housing I and assists them to fall into the bottom part 3 of the housing.

In such cases the scrapers 43 provided on the valve shaft 20 are unnecessary.

The continuous rotation of the valve cone, which is an essential feature of the invention;

can naturally be produced by means other than those described above without departing from the scope of the invention. Thus, for instance, in-

stead of the worm mechanism 36, 31 a ratchet 'mechanism or a friction wheel mechanism may be used. Further, the rotation mechanism may be and distillation thereof, comprising in combination an expansion chamber, an inlet and outlet .universal joint connecting said spindle and said intermediate shaft section, a driving shaft, a

universal joint connecting said intermediate shaft section and said driving shaft, means for rotatably supporting said driving shaft in said chamber, means for loading said valve member and driving means connected to said driving shaft to effect rotation thereof.

2. Apparatus for the expansion of hydrocarbons after heating under pressure for cracking and distillation thereof, comprising in combination an expansion chamber, an inlet and outlet therefor, a pipe connected to said inlet and supported in said chamber, a valve seat in said pipe, a valve member adapted to rest on said seat to close said inlet, a spindle connected to said valve closure member and slidably supported in said chamber, an intermediate shaft section, a universal joint connecting said spindle and said intermediate shaft section, a driving shaft, a universal joint connecting said intermediate shaft section and said driving shaft, means for rotatably supporting said driving shaft in said chamber, means for loading said valve member, driving means connected to said driving shaft to effect rotation thereof, and a knife-edged scraper fixed to said valve member and protruding into said pipe.

3. Apparatus for the expansion of hydrocar bons after heating under pressure for cracking and distillation thereof, comprising in combination an expansion chamber, an inlet and outlet therefor, a pipe connected to said inlet and supported in said chamber, a valve seat in said pipe, a valve member adapted to rest on said seat to close said inlet, a spindle connected to said valve closure member and slidably supported in said chamber, an intermediate shaft section, a universal joint connecting said spindle and said intermediate shaft section, a driving shaft, a universal joint connecting said intermediate shaft section and said driving shaft, means for rotatably supporting said driving shaft in said chamber, means for loading said valve member, driving means connected to said driving shaft to effect rotation thereof, and scraper members fixed to said shaft to rotate therewith, said scrapers engaging with the sides of said chamber.

4. Apparatus for the expansion of hydrocarbon after heating under pressure for cracking and distillation thereof, comprising in combination an expansion chamber, an inlet and an outlet therefor, a pipe connected to said inlet and supported in said chamber for conducting hydrocarbon under pressure to said chamber, a valve seat on said pipe, a valve member adapted to rest on said seat to close said inlet, a freely slidable shaft rotatably supported in said chamber, a universal joint connecting said shaft and said valve member, a scraper fixed to said valve member and pro-

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