US1862758A - Art of rectification - Google Patents

Description

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um@ p i933 S, R MERLE? ART oF RECTIFICATION Filed Feb. 9, 1929 @5% his @e @Uilm my w32 s. R. MERLY ART OF RECTIFICATION Filed Feb. 9, 1929 2 Sheets-Sheet 2 CoNoeNsA-n-E. OUTLET HNVENOR SYLAN MERLEY Patented June 14, 1932 UNiTED STATES- PATENT orricr. i

SYLVAN E, MEELEY, OF DOVER, NEW JERSEY, ASSIGNQB TO DOHERTY BmEARCH COM- EQLNY, OF NEW YORK, i'. Y., A COBJPORATIQN OF DELAWARE ABT QF BECTHIGATION Applioaon le February 9, i929. Serial No. 338,811.

This invention relates to the art of rectification and bubbler plate columns, particularly to a special tray and liquid overiow construction and mode of operation.

lin most distillation and rectification.

processes the condensate mixtures involved are completely homogeneous and miscible in all proportion at the temperatures existing in the rectifying column. In such processes the vapors rising through the liquid on the trays of the column come into contact with constantly changing concentrations on the trays, depending on the temperature gradient and number of trays in the column. Some liquid mixtures, however, do not remain completely miscible in the various proportions in which they occur in a rectifying column but separate into two layers on atleast some of the trays. When this condition occurs in the ordinary column the Iupper layer on a particular tray overiiows nrst and becomes a mere nlm on the surface of the lower heavier layer.

Under these conditions, an abnormal condition is created in the column since the tray or trays on which the liquids separate do not contain the proportions of the liquids which would normally condense and be maintained thereon as in the case where the liquids are completely miscible.

Therefore the present invention has as its primary object the provision of a method and a structure particularly adapted to overcome these di iiiculties. in accordance with which the invention comprises a bubble plate column in which means are provided for maintaining on each tray considerable portions of two immiscible liquids which may separate thereon.

The invention includes other objects and advantages which will be apparent from the following description taken in connection with the accompanying drawings in which Fig. 1 is a broken vertical sectional view of a portion of a bubbler tower showing a single tray embodying the features of the invention;

Fig. 2 is a horizontal sectional view of Fig. 1 looking down upon the line 2-2;

Figs. 3 and d are views similar to Fig. 1 showing modified forms of the overflow'mechanism shown in Fig. 1; and

Fig. 5 is a diagrammatic view of' a complete bubble tower with parts broken away to show the application of the apparatus according to one modication of the present invention.

Referring to Figs. 1 and 2 of the drawings, the numeral 2 represents a portion of a side wall oi a hubbler plate column of the type used for the rectification of vapors, and lione of a series o vertically arranged bubble trays mounted therein. This bubble plate or tray s is provided with conventional bubble caps one of which is shown at j6. Each tray is provided with a condensate overflow pipe 8 which deliversthe condensate from one tray to the next lower tray in the column.

The present invention is more particularly concerned with certain improvements in the method and means for regulating the dow of liquid from one tray to another by means of the pipes 8.

In the treatment of mixed vapors which condense to form two immiscible liquids on the trays oi' a bubble column the lighter liquid layer overflows first so that only a film is left on the tray. In order to secure proper rectiication and intimate contact with both liquids in the proportion in which they are condensed the present apparatus includes an additional overflow band or pipe section 10 which is spaced from and around the upper art of the overiiow pipe 8 as shown in Fig. 1. The band 10 may be supported in any convenient manner -such for example as by slotted brackets 12 attached to the pipe 8. These brackets together with the necessary bolts hold the band 10 in the desired position so that the heavier liquid flows under the band 10 and directly into the pipe 8 while the lighter liquid is held to a higher level by the band, over which it then iiows into the overiiow pipe 8.

' The slots in the supporting brackets 12 permit of a ready adjustment of the height of the band 10 above the top of the pipe 8 so that the relative amounts of the two liquids on each tray can be controlled in substantial accordance with the amount-of each liquid condensed thereon and delivered thereto from the upper trays,-or in accordance with the 190 amount of each liquid whichl would be on the tray at the particular temperature, if the liquids were completely miscible.

The overflow pipe 8 terminates at its lower end in a liquid seal cup 14 which may be above the liquid on the next tray below. Near its lower end the pipe 8 is provided with a branchpipe 16 which extends into the cup 14 only a comparatively short distance compared with the main pipe 8. A bah'le 18 is placed above and over the outlet from the pipe 8 to the pipe 16 to prevent direct entry oi the liquids thereinto. The function of the branch pipe 16 will be apparent when it is realized Jthat in its absence the lighter of the two immiscible liquids entering the pipe 8 must accumulate in the lower end of the pipe until its weight is siicient to overcome 'the height of heavier liquid in the cup, before it can he discharged around the lower end. Such operation would give irregular flow of the two liquids onto the trays and cause the baclring up oi: lighter liquid in the overdow pipes. With the branch pipe 16 however, the lighter liquid can Je regularly discharged through a shallow seal and thus avoid the dii'iiciilties mentioned.

If desired the pipe 8 and branch pipe 16 may seal directly in the liquids on the trav onto which they discharge, but the cup 1li: has a distinct advantage ease ci siphoning of tray liquid through the hiihble caps, which would uns-eel the overdow pip-es and thus give a bypass for vapors until suiTicient eenden sate been :formed to .magre a seal.

In order to secure goed .,of

liquids on each tray anar agitation near the vi n 2G may compie overa T i erahly spaced from the han@ l above the liquid level on. tli t Fig. represents a inodii'ied -lerici? ag in which an overflovparatus 1 v charges the iight-er liquid vinile a second 1 i pipe 22 Efiprovided with a vented cap to. discharge the heavier liquid and still maintain a. considerable quantity of lig t liciuid on the tray. lli/leans for adiustiiig the relative heights oi the pipes 22 and 2li while not shown may taketlie 'form of a threaded sleeve on one of the pipes and the discharge end of pipe 22 may have a seal comparable to the branch 16 iii Fig. l.

/l shows a further modification O the overflow mechanism in which the upper end of the pipe 8 is provided with a branch line 28 adapted to discharge the heavier liquid into the pipe 8 at a selected point below the upper edge of the pipe 8 over which the lighter liquid Hows.

Fig. 5 shows the apparatus of the presen-J invention applied to a complete bubble tower 30. In this ligure is shown the apparatus according to the modification illustrated in Fig.

3, but it is to beunderstood that any of the various modifications according to the present invention may be applied in a similar manner. Fig. 5 also shows a screen 32 which operates substantially as screen 20 of Fig. 1. Such a screen may be used with any of the modifications shown.

The form of the column whether circular or rectangular in cross section is unimportant to the present invention, but where a long wier overiiow extends across the side of a column, a vertically adjustable plate or dani may be placed in front of the wier to maintain the level of the lighter liquid in the same manner as the band 10.

The term liquid as used in the speciiicasolubility water under the conditions.

The drawings showing the various forme of the invention are merely diagrammatic and theieore no attempt is made to accurately proportion the various a ed the invention in itsprererred is claimed. as new is:

l; A vapor rechi .drag colnmn,-coniprising a p iurali'ty of vertically spaced hubhler tray-fi, a iiquid cveiiiow pipe prg-sting alcove tray., for alayer of condiensaixa on i r conduct ri .relatively heavy densate therercua c and a vertically spaced riferi, serre .rag projecti :g above the upper prog ing end of' said over iiow .pipe for mcifitainiiig a. higher level of relatively light condensa-te on tray.

21. A vapor column, comprising a piiirality of ve... 'ically spaced hiihbler trays, a liquid overciw pi;VM eci' each tray, the upper end. of which projects above the tray, for maintaining ahody ci ccndensafsieftliereon, means a liquid seal for tie lower end of each pipe, vertically adiustable band surrounding and projecting above the upper projecting end ofi said pipe, and a branch pipe connecting with the lower lor tion of each overow pipe and projecting into said liquid seal to a iess extent than said overflow pipe.

3. ln the art of rectiinying vapors-which condense to i'orm at leas two iininiscilile liquid condensates, the improvement which coniprises passing the vapors through bodies of condensate maintained in separate zones at dierent levels, maintaining portions of each condensate in the zones in which they would exist as liquid at the particular temperatures on the zones, and in substantially the pro- 2t lower tray.,- 't

Lacasse portions in which they would be present if the condensates were completely miscible, and overflowing portions of each condensate from one zone to the next lower zone counter to the flow of vapors through said zones. Y

4. In a bubbler tray column, a hubbler tray, a condensate overflow apparatus therefor, 'comprising an overflow at one level for av heavy liquid, an overflow for a lighter liquid at a higher level, and means for preventing the direct entry of lighter liquid into said first mentioned overflow 'at the overflow level for the heavy liquid. l

5.- In a bubhler tray column, abubbler tray, a condensate overflow apparatus therefor, comprising an overiow at one level for a. heavy liquid, an overflow for a lighter liquid at a higher level, means for preventing the direct entry of lighter liquid into said first mentioned overflow at the overow level for heavy liquid, and a screen surrounding said overflow apparatus for maintaining the liquids in a relatively quiescent state.

In testimony whereof I ailix my si ature.

SYLVAN R. MER EY.

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