US540655A - Manufacture of acetic acid an d apparatus therefor - Google Patents

Description

(No Modell.)

r Y 4 Shets-Sheet 1. J. FARMER. MANUPACITURE. 0F AGETIG ACIDl AND APPARATUS' THEREFOR.

Patented 111.1111011, 1895.

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- J. FARMER. MANPAG'IURE OP AGETIG ACID AND APPARATUS THBREPOR.

Patented June l1, 1895.v

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(No Model.) l v '4 Sheets-Sheet 3. J. FARMER.

MANUPAGTURB 0F AGBTIG ACID AND APPARATUS TEEREPOR. No. 540,655. Patented 'June 11, 1895.

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J. 15111111511. MANUFAGTURE 0F AOETIG ACID AND APPARATUS THEREFOR. 115. 540,555. m5111511 June 11, 1895.

, UNITED STATES PATENT y OFFICE. l

JOHN FARMER, OF POLLOIISHIELDS, SCOTLAND, ASSIGN ORTO THE CHARLES LENNIG da COMPANY, LIMITED, OF PHILADELPHIA, PENNSYLVANIA.

MANUFACTURE QFACETIC ACID AND APPARATUS THEREFOR.

SPECIFICATION forming part of Letters Patent No. 540,655, dated June 11, 1895. Application filed .Tune 28, 1892. Serial No. 438,286. A(No model.) Patented in England August 22, 1889, No'. 13,264.

' To al'whom it may concern..-

Be it known that l, JOHN FARMER, a sub-V i jectof the Queen of Great Britain, residing the manufacture of acetic acid, and consistsV especially in the arrangement and combination of partsof apparatus for the distillation of acetic acid from any of the acetates most commonly used, such as acetate of lime; and the object of the invention is to produce acetic acid in a purer state and in a simpler and more efficient manner than heretofore.

Referring to the accompanying drawings, Figure lis aV sectional elevation, and Fig. 2 is a plan corresponding to Fig. 1, both showing an acetic-acid still as constructed in accordance withy my invention and embodying and illustrative of one arrangement and combination of the improvements thereof. Fig. 2fl is a detail. Figs. 3 and 4. 'are respectively a sectional plan and a sectional elevation ot' modification. Fig. 5 is a sectional elevation, showing the application of my improvements to an ordinary acetic-acid still.V

Referring to Figs. 1 and 2, A is the lower body of the still, preferably formed of cast iron and cylindrical in shape lined internally at A', with segmental ireclay, tiles or bricks or other equivalent to resist the' action of the distilledvoff acid vapors or gases, especially at the upper part of the still A.

B B2, is the steam heating worm coil pipe fitted inthe lower part of the vessel for heating and boiling the material under treatment;

and C C are the pipesy for drawing the dis-` tilled off vapor or gas from the"top, and leading it down through the condensing worm D fitted within the cold water condenserl D', which ihay be of any ordinary construction, supplied by water from the pipe D", from any overhead' source of supply and run off by the overflow branch D2.

By my improvements I form in the inside of the metal or equivalent close heating pot or still A, near the top and outside a cavity, recess, or gutter chamber a below and rising above the top A of the still vessel A, and either jointed at a" as shown in Fig. 1, or formed in one with the outer case A'of the still, as shown in Figs. 8 and 4, and preferably annular as shown in the drawings, capable off holding any suitable purifying liquor filledt into it at a below vthe top A of the body of the still A, and I place over the still and partly over this recess or gutter a a cover or lid b, b of gun-metal, stone, or other suitable material, which will resist the action ot the gas, and supported at its vertical lip b' onV bricks or other equivalent at h and having its lower outer edge or rim b turned down to dip a few inches into the said liquor, which forms a seal through which the vapor or gas as it ascends from the still below must pass under the turned down edge and through the liquor stone or other cover A3 jointed over the whole top at A' as shown in Figs. land 2, or it might be only over the outer annular part a as'hereinafter described in reference to Figs. 3 and 4.. To the top of this cover A3, a copper, delf, or other suitable pipe C is luted to convey the gas distilled off direct by the knee branch C' to the worm E of the condenser D', and from the lower part of the worm D, it issues as finished commercial liquid acetic acid at D2. The gas in the still A under this last upper cover A3 referred to (after it has passed through the sealing cover b and liquid CW) being in free communication with the atmosphere through the condensing worm D, and it having thus little or no pressure outside the seal and lip b of thecover b, a putty or. clay' joint at A is all that is required to keep this cover and its gas pipe C tight,thus the trouble, expense, and waste through leakage.v of keeping the ordinary large still covers tight under the pressure of an acid gas, as when stills are used with the old style of small puriiers or traps placed outside andindependent of the still is entirely avoided. VThe liquor A in the gutter a of my still is kept heated suciently by means of a steam pipe c which ICO may receive its steam from any suitable source, as from the steam pipe B which conveys the steam to the heating Worm B. The steam pipe c serves not only to keep the trapping liquid at a proper temperature, but it may also be used for the purpose of boiling down this purifying liquid and maintaining it at a uniform and proper level. I screw an open-mouthed stand or drawing off branch pipe c' from the outside of the still up through the sealing gutter or chamber trap a and reaching a little above the level for emptying or reducing the liquor within it. This I do by screwing the pipe downward the distance, according to the amount of liquor desired to be drained off from, or level to be maintained in the trap a. The liquor so run off may belet direct into the still through a branch pipe c" fitted near to the bottom of the still A, but having an open mouth directly under this draining pipe o', or the liquor may be run into a separate vessel for subsequent use.

The still A is provided with door or doors C" at bottom for drawing off the residual charge after acid has all been extracted, and would also have glass sight holes or gages at C2 to ascertain the height of charge in the still. The still A may be hea-ted by an open fire, but preferably by the steam copper coil B, B2 placed inside, with suitable steam cocks and condensed steam-connections B B and drawing oit condensed water pipe B'".

The opening covered by the door C is adapted not only to serve as a draw off opening through which the contents of the still can be discharged, but also as a man-hole through which an attendant can pass into the interior of the still for the purpose of elean ing it out or repairing it. In order to permit such passage of the attendant into the still, the lower coils B2 of the steam pipe do not extend in front of the door, as shown in Fig. 2, but are of substantially horseshoe shape. This enables the attendant to easily enter the still even while the steam pipes are in place.

To prepare the still A for starting the distillation, a charge say of common acetate of lime and muriatic acid is introduced into the still at the opening or door pipe E near the top fitted with a portable closing lid E. This charge should cover the steam heating coil B to about the level indicated ate. A purifying liquor composed preferably 'of a mixture of a very pure acetate of lime and muriatic acid and having the tar carefully skimmed off, is run into the trap gutter a through a suitable .plug opening at a2 in the top cover A3 to form the seal with the inner cover l), through which the gas has to pass, in escaping to the pipes C C and condensing worm D, and should it be important, for instance to remove most of the tar from the acetic acid being distilled, parafiin wax may be put into the outer division of the seal in gutter ci and will float on the top of the liquor already introduced on the outside A2 of the cover I) as indicated at a3 Fig. 1. Paraffin Wax makes a good separator for the tar and has been worked in these old outside and separate purifiers or traps already referred to, but with indifferent success owing greatly to the choking up of pipes and difficulty of cleaning and recovery of the paraffin. The large area of this new purifier causes a slow speed of the gases passing through it, and the absence of small pipes allows this purifying agent to be easily used when desired. The use of the mixture of acetate of lime and muriatic acid, paraffin, or other equivalent 'liquid with this mode of trapping the gases at the top cof the still relieves the pressure on the escaping gas and enables the distillation to be continued for much longer periods than heretofore without removing the tops of the stills. Other purifiers than those named may be used in this new and improved trap o., the nature of which will depend upon circumstances. Steam be ing admitted into the coil B B2 acetic acid is liberated from the charge as vapor and passes up and through the purifying liquor a inthe trap a thence by the large pipe C, C to condenser D, D all as indicated by the arrows in Figs. l as before described.

To expedite the process of distillation, toward the end, it is a common practice to inject live steam directly into the still as near the bottom as possible. 'lhisis generally done throughan open-mouthed copper pipe fitted inthe still, but this does not permeate the mass of acetate of lime sufficiently owing to the steam being confined to one part. Vhen the pipe is perforated with small holes to distribute the steam, these holes very often choke up during the time they are lying in the still out of action. To remedy this I joint and screw to a branch A* at the side of the still A at bottom, a fianged gland gun metal stuffing box f of say one or two inches in diameter shown in separate end view in Fig. 2, which has a round pin f passed liquid tight through it, with a head on the inside to prevent it being drawn out through the stuffing-box, and outside of the stuffing box a stop or cotterf is inserted in the pin f to prevent it being accidentally pushed inward. The point of the pinf projects a few inches beyond the stuffing boxf and its end is reduced in diameter and screw threaded to engage with a plug which fits into and closes the end of the steam pipe f2, as shown in section in Fig. l of the drawings. A copper pipe fza little longer than the diameter of still Aand the same external diameter as the pin f is prepared by having its surface perforated with small holes nearly its whole length, and the inner closed end of this pipe f2 is screwed to tit the outer Screwed end of the pin f while the other outer open end of the pipe has a coupling and india-rubber steam hose pipe fi attached to it, led from the main supply steam pipe B', fitted with a stop valve or cock B3. This perforated pipe f2 is shown in its outmost position in Figs. 1 and 2 and in its inner acting position in Figs. 3, 4 and 5. Then live steam stuffing box f and charge of material in the lower body ot' the still, and the steam being turned on by the valve B3 now passes up through the perforations in the pipe f and i charge in the still; and the pipe f2 can be drawn backward-and forward from time to time.

The lower coils B2 of the steam heating worm B B2 where theyvlead to the drain pipe B are undulated and tted in the form of a horse shoe, as indicated inidotted lines in Fig. 2, so as to allow of the perforated steam pipe f2 being inserted and withdrawn as described.

It will be observed that the upper end of the still proper, A, is entirely open and that the trapping chamber surrounds the opening therefrom. This arrangement is advantageous for the following reasons: It insures that the passage of the gases or vapors away from the still and through the trapping liquid shall be steady, and comparatively slow, which would not be the case were the opening from the still contracted as is usually the case. Another advantage is that a singletrap is sufticient for the ordinary purication of the vapors, as the trap is of large or relatively large size, and the passage of the vapors through the same is slow. Besides these advantages I secure the requisite purification of the gases, by means of the liquid trap, without necessitating a very considerable enlargement of the apparatus beyond the side of the still proper A.

Referring to the acetic acid still shown on Figs. 3 and 4 the main improvements in this still are all substantially the same as described in reference to Figs. l and 2, and lettered to correspond, so that I need now only describe the features of the improvements of this modification in so far as they are different from Figs. l and 2. In this arrangement the annular trapping chamber a. is shown as formed or cast in` one with the upper part of the body of the still A; and made wider and all lined with segments of tirebrick ctx on the inside and covered at the upper top A of the body of the still A, with segmental fireclay blocks AX. The trapping rim b in this case is formed as a deep annular ring resting on bricksat b with interstices between them for the escape of the gas in the center of the trapping chamber a, and is also lined on both sides with segmental tire bricksl or blocks bx to protect the iron from the corrosive action upper outer edge-of' the covery A5 and the ange A" at the top of the trapping chamber ct to cover the outer annular top part of this trap ot, which forms the seal. When this is done, the gas is taken from the outer di-V ameter of the still A, by the branch C and pipe C through a hole in one of the slabs A5, just over the outer part of the seal as shown particularly on the right of Figs. 3 and4c and not from the center of the top A5 of the still as shown in the lirst arrangement, lwhich thus dispenses with the necessity of removing the large cover A3 as in Figs. l and 2, as the trapping annular chamber ct can be cleaned out from time to time by merely lifting out the small segmental tiles A5 over this chamber a. In this arrangement the acetate of lime and muriatic acid, or other material to be treated is filled into the still A through a central hole or door E in the stone top A3 covered in by a portable fireclay or other block Ez'jointed over this door E.

The drawing off branch c is shown as inserted laterally through a stuffing box in the bottom of the trap chamber a formed with a sight glass at c" so that this branch c may be turned upward to observe and regulate the level of the liquid a. in the trap a or to ll inthe liquid or be turned downward to any angle to draw off the trapping liquid to any level when desired.

Referring to Fig. 5, this shows the application of my improvements to an ordinary acetic acid still A. In this arrangement an additional piece B4 is tted and bolted by ianges B5 to the top of the still A, and the trap wall is formed by adding a conoidal rim a, of copper, brass, or other sheet metal screwed liquidtight between the said flanges B5 of the top piece B4 and still, and the luting or trapping arrangement is formed by cementing and securing a correspondingly formed conoidal rim b in a groove cover stone, and jointing the gas branch C over an opening in the cover above the escaping part A2 of the trap a, and in filling into it the luting purifying liquid d, which in this case is preferably paraffin scale, through the plug hole CL2 over this said recess A2 at the opposite side to the gas drawing-off pipe C. For insuring that the level of the paran or other trapping and purifying liquid a shall not iow over the upper inner lip of the trap a, a trap drawing off branch c', c

is fitted by a liquid-tight screw gland or stuff# ing box, which can be turned round or inverted from the position shown in Fig. 5, to draw o all the liquid from the trap A when desired. The perforated steam blowing off pipe f2 in this ligure is tted with a hollow pin f on its inner end, and shown as inserted in its inward acting position.

What I claim isl. In a Istill for the distillation or manufacture of acetic acid, the combination of a still provided with a stuffing box near its lower portion, and a perforated steam pipe adapted to IOO IIO

slide longitudinally through the said stuffing box into and out of the still, substantiallyas set forth.

2. The combination with the still of the gut ter, a stand pipe adjustably mounted in the gutter and a pipe connected to the still arranged under the stand pipe and adapted to receive the liquid which may be drawn off through the said adjustable stand pipe and conveyed back into the still, substantially as described.

3. The combination with the still, of a stuing box near the bottom thereof, a perforated pipe adapted to slide longitudinally through the said stuiing box into and out of the still, and provided at its inelosed end with an enlargement whereby the steam pipe is prevented from being accidentally Withdrawn from the stuffing box, substantially as described.

4. The combination with the still provided with a stuing box near its bottom, a perforated steam pipe adapted to slide into and out of the stillthrongh the said stuffing box and means for locking the said pipe in its drawn out position, substantially as set forth.

5. The combination with a still provided with astulng box nearits lower end, a headed pin f adapted to close the opening through the stuffing box, means for holding the said pin in place and a steam pipe for heating the contents of the still adapted to be connected with and disconnected from said headed pin, and when connected therewith to be slid through the stuing box, into the still, substantially as set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

JOHN FARMER. lVtncsses:

`JOHN SIME, JOHN MONTGOMERY.

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