US2347271A

US2347271A - Feed device

Info

Publication number: US2347271A
Application number: US311831A
Authority: US
Inventors: Norman F Linn
Original assignee: Standard Oil Development Co
Current assignee: Standard Oil Development Co
Priority date: 1939-12-30
Filing date: 1939-12-30
Publication date: 1944-04-25
Anticipated expiration: 1961-04-25

Description

Aprilzs, 1944. N EUNN v2,347,271

FEED DEVICE Filed Dec. 50, A1939 I GA; VAroA Pmi-,3

- Patented Ape. 2s, 1944 Norman F. Linn, nooene, ruin. N. J., ossimor- `so Standard il Development Company, a corporation of Delaware Application December 30,1939, Serial No. 311,831

3 Claims.

The present invention relates to an apparatus for feeding finely divided pulverulent materials into a high pressure zone from a zone of lower pressure. More particularly, the invention relates to a means for discharging inely powdered catalyst materials into a cracking vessel or a feed line thereto, in which a gaseous material is contained under a substantially higher pressure than that existing in the reservoir for the powderedmaterial, or outside the line. Specifically, the invention relates to a pocket type feed mechanism providing for the more or less continuous introduction of powdered catalyst under the circumstances set forth, and to the combination of such a mechanism with other elements in a complete system.

It is an object of the inventionto provide for the continuous introduction of a powdered matethrough a restricted opening or slot 1 at the end of the plate I. The powdered material from the hopper s carried through the easing in the powdered material in the line ..but also to prerial into a zone of higher pressure without blow` back' or pressure loss, and also to prevent any packing or coking of the catalyst material in the vicinity of the point of introduction.

These objects and` others inherent .in the structure and operation may be fully understood from the following speciiication when it is read netos a cylindrical member having about its Iperiphery a series of,helical pockets 2, cut in the face of the member I in such manner that one end of one pocket is disposed in spaced.

l slightlyoverlapping relation to the other end-of another, along a line parallel' to the axis of said member. For the'purpose of the description. the cylindrical member I may be termed a feed wheel, the pockets 2 being formed or cut between spacing portions I. These angular. arcuate pockets 2 are preferably formed or out in the feed wheel at an angle of not more 30, with reference to the axis or a surface line parallel thereto.

As shown in Fig. 2, a. feed wheel 1 is disposed within a casing 4the casing opening upwardly .and exposing the feed wheel surface within a hopper or reservoir 5,- and opening downwardly into a zone of higher pressure, such as line t,

rf ci vent the 'reactive material from coming in contact with the powder before it leaves the feeding mechanism.'

Various means may accumulation of caked material on the surfaces 3 of the feed member I between the respective pockets 2, such as may be caused by pressure between the closely spaced surfaces of the feed wheel and casing. For example, the edge portion of the plate I may be held againstthegear under slight tension so as to act as a scraper to remove any particles adhering thereto'.l

Figs. 2 and 3 illustrate the simplest arrangement of elements according to the invention, the powdered material .being discharged directly from the reservoir therefor into the reaction zone inlet line. As shown in Fig. 2, the discharge plate 8 is disposed diametrically opposite -tlie hopper outlet. In the structure illustrated by Fig. 3, however, provision is made for balancing the pressure seal desired between the reaction zone or vessel inlet and the reservoir. In this arrangement, the plate l is disposed at a point about from the hopper outlet in the direction of rotation of the feed wheel. When the pockets pockets are empty and the seal depends almost entirely upon the surface to surface relation between the case and feed wheel. a greater coni tact or sealing area is desirable. The desired balance between the sealing areas' is obtained substantially in the manner shown,

The structure shown according to Fig.4 is `particularly suitable for use when the pressures existing in the reaction vessel, or adjacent the point at which the powdered material is to be introduced, are exceptionally high.v As illustrated, the feed wheel mechanism is combined with a screw type feeder. In addition to the fact that this combination improves the seal obtained,

be utilized to prevent the it has been found that when thus combined, the constancy and uniformity of the feeding step is greatly improved also.

In the structure shown, powdered material is introduced into the line 9 through line t, by

means of the feed member I. 'Ihe powdered material to be handled by the feed wheel i is received by way of the line Il in which is disposed a constant diameter screw feed member I2, the line il communicating with a hopper or reservoir i3. The screw feed member l2, while it may be constant in pitch as well as diameter, is preferably of decreasing pitch, so that an increased sealing effect may be obtained. The relatively large volumes of solids receivable in the 'rst few nights of the screw are compacted into the smaller volume of the'smaller flights, producing the desired result. Although a screw feed mem-- which the gear i revolves. This form of structure is illustrated, and it has the advantage of provid-l ing for the redispersion of the powdered material discharged from the screw member. aiding in avoiding-the formation of lumps of compressed material. That portion of the line il in which such re-dispersion is to take place is indicated as chamber Ila. The screw member and feed wheel when thus combined are intended to be rotated -by power derived from the same source, their speeds f rotation andtherefore their rates of delivery being adjusted to their respective capacities.

The structure as described is suitable for use in a variety of operations, but itis particularly adapted to combination in a process for the cracking of hydrocarbon materials in the presence of a nely divided or comminuted catalyst material such as activated clay. In such a process, large volumes of catalyst must be supplied to the system in a continuous fashion, and at a rate which by its uniformity wil1 maintain the proper ratio between the volume of catalyst and the volume of the reactive materials. As disclosed, the apparatus contemplated provides a means by which the feed rate of catalyst may be maintained within the desired limits, while avoiding the eifects produced by escape or blow-back of portions of the reactive material into prematurecontact with the catalyst material to cause coking and clogging of the mechanisms and passages through K I c: y

l. In an apparatus for feeding powdered catalyst into a reaction zone for the heat and pressure treatment of hydrocarbon material, a high pressure reaction zone adapted to contain the `hydrocarbon material under elevated temperai ture and pressure, a reservoir for the powdered catalyst at lesser temperature and pressure, a conduit connecting the zone and reservoir, a feed wheel for positively feeding the catalyst from the reservoir into the conduit toward the zone at a constant and uniform rate, the feed wheel comprising a cylindrical member with relatively wide peripheral spacing portions between a series of helical pockets, the spacing portions cooperating with the wall of the conduit to form a substantially fluid-tight t, and an inlet for fluid inert to the hydrocarbons opening into the conduit between rthe wheel and reaction zone to iluidize the powdered catalyst on itsway to the reaction zone and prevent the hot hydrocarbon material from contacting the catalyst before the catalyst leaves the feed wheel.

2. In an apparatus for feeding powdered catalyst into a reaction zone forthe heat and pressure treatment of hydrocarbon material, a high pressure' reaction zone adapted to contain the hydrocarbon material under elevated temperature and pressure, a reservoir for the powdered catalyst at lesser temperature and pressure, a conduit connecting the zone and reservoir, a feed wheel for positively feeding the catalyst from the reservoir through the conduit toward the zone at a constant and uniform rate, and a compression screw member in the conduit between the reservoir and the feed wheel, the feed wheel comprising a cylindrical member with relatively wide peripheral spacing portions between a series of helical pockets, the spacing portions cooperating with the wall o1' the conduit to form a substantially duid-tight fit'. f

3. In an apparatus for feeding powdered catalyst into a'reaction zone for the heat and pressure treatment of hydrocarbon material, a high pressure reaction zone adapted to contain the hydrocarbon material under elevated temperature and pressure, a reservoir for the powdered catalyst at wall of the conduit to form a substantially iiuidtightt, and an inlet for iluid inert to the hydrocarbons opening into the conduit between the wheel and reaction zone to iiuldize the powdered catalyst on its way to the reaction zone and prevent the hot hydrocarbon material from contacting the catalyst before the catalyst leaves the feed wheel.

- NORMAN F. LlNN.