US 1409588 A
Description (OCR text may contain errors)
OBTAINING TAR ACIDS.
APPLICATION FILED FEB. 8, 1918.
1,409,588. Patented Mar. 14, 1922 Non Held 50/,
Fee 'EIr/IcI T MlVE/V TOR fl/J ATTORN Y8 UNITED. STATES PATENT OFFICE.
WALTER RUNGE, OF ORANGE, NEW JERSEY, ASSIGNOR T0 INTERNATIONAL COAL PRODUCTS CORPORATION, OF RICHMOND, VIRGINIA, A CORPORATION OF- VIR- GINIA.
- OBTAINING TAR ACIDS.
' Specification of Letters Patent. Patented 11 14 1922 Application filed February 8, 1918. Serial No. 215,992.
To all whom it may concern:
Be it known that I, WALTER RUNGE, a citizen of the United States, and a resident of Orange, in the county of Essex and State of New Jersey, have made certain new and useful Improvements in Obtaining Tar Acids, of which the following is a specifito 170 degrees C. a light oil fraction is derived; where the maximum temperature is up to 230 degrees C. a middle oil fraction is derived; where the maximum temperature is up to 270 degrees C. a creosote oil fraction is derived, and where the maximum temperature is up to 360 degrees C. an anthracene oil fraction is derived.
These several fractions are, respectively, referred to as the light oil, middle oil, creosote oil and anthracene oil. Each fraction thus obtained contains tar acids and herein applicant is interested only in the light oil and in the middle oil; The light and middle oils each contain the tar acids above enume rated, to wit, phenol, cresylic acid and the higher homologues, and which it is the purpose of the present process to quickly and cheaply obtain. Said light and middle oils also contain certain hydrocarbon oils.
According to the process herein described the light and the middle oilscaneach be treated separately, or they can be treated together, dependent upon Whether the hydrocarbon oils of each fraction are to remain separate and thus be recovered separately, or whether the hydrocarbon oils of both fractions may be mixed and as thus mixed to ether be recovered.
he light oil, that is the light oil fraction,
and the middle oil, that is the middle oil fraction, contain several different oils some of which prominent oils are as follows:
Light Oil. Middle Oil. Benzol, Solvent naphtha, Toluol, Heavy naphtha, Solvent naphtha, Neutral oil, Phenol, and Phenol,
Higher tar acids. Cresylic acid, and Higher tar acids.
As previously indicated the present invention is particularly directed to the sepa-.
trated diagrammatically in the sole figure of the accompanying drawing. The phenol, cresylic acid and higher tar acids may be referred to as the M acids orthe tar acids and-may be designated by the symbol MOI-I, in which the M represents the base element ofthe tar acids, such as in the case ofphenol.
where M would represent the radical C H or in the case of cresylic acid Where M would represent the radical 'C,,H,.CH,', and so on for the higher taracids. In case of mixtures containing a plurality of acids then M represents the base of each acid as, for example, C H,; C H,.CH which represent the bases where the mixture had phenol and cresylic acid. The constituents of the light oil group and of the middle oil group collectively may be broadly referred to as the aromatic derivatives divisable into acid solutions which are the M acids and non-acid solutions. The M or tar acid solution includes, as just indicated, the
phenol, cresylic acid and higher tar acids,
while the non-acid solution includes benzol, toluol, solvent naphtha, heavy naphtha and neutral oils.
In the performing of the invention the l soda to form the sodium salt of the M or tar acids, as is shown by the following equation;
MOH NaOH H 0 MONa The M or (aqueous solution oi (sodium salt (excess at acids) caustic soda) of tar acid) water) The operationjust referred to is carried out in a tank (an agitator) with. a itation for a peroid of 2 to 6 hours and by t is agitation the M or tar acids are brought into intimate contact with the caustic soda in the solution to assist the reaction. At the end of this period the agitation is arrested and the contents of the tank allowed to settle.
. The solution of the sodium salts of the tar acids, being of higher gravity than the nonacid solution, settles to the bottom and the non-acid solution rises. There is a sharp line of demarkation or division where the two solutions meet and due to this physical characteristic 'of the two solutions they may be separated mechanically. This mechanical separation may be effected as by drawing oil the solution of the sodium salt of the M or tar acids; in other words, the Mor tar acid sodium salt solution may be separated mechanically by this drawing ofi' operation from the non-acid solution. The M or tar acid sodium salt solution is now treated by brin ing into contact therewith and while under pressure carbondioxide CO either as pure C0,, or as the CO containing any mixed gases as, for example, flue gases. The CO gas is preferably brought into intimate contact, as by bubbling, that is by blowing jets of CO in the aqueous solution containing the sodium salt of the M or tar acids (the MONa.)
The reaction which takes place is as follows:
. 2MONa 00 H O ZMOH N a OO (sodium salt of (carbondi- (water) (free tar acid) (sodium carbon- M or tar acid oxide) (light liquid) ate in SOllltlOl]. in solution) (carbonic acid) in excess H2O) The solution of sodium salt of M or tar acids is under substantially super-atmospheric pressure, preferably of 100 pounds, during the time the reaction just described is taking place. Other methods than bubbling for bringing'the CO gas into intimate contact with the M or tar acid sodium salt solution maybe employed.
It will be understood, 'however, that an important feature of the present invention is the employment of said pressure which expedites the ultimate reaction. During the process the pressure is maintained substantially super-atmospheric, preferably at 100 pounds, by supplying additional Ct) under pressure to replace the CO absorbed as the reaction progresses. If CO is supplied by the introduction of flue gas the inert gases that necessarily constitute a part of flue gas are left and collect in the chamber'as the reaction progresses. These inert gases that collect are withdrawn as desired, or when they become too great in volume. As the M or free tar acids (MOH) are relatively light or of low specific gravity and as the aqueous solution of sodium carbonate is heavy or of high specific gravity the M or tar acids will be readily separated from the aqueous sodium carbonate solution. It will, therefore, be seen that the sodium carbonate solution separates, due to gravity, from the M or tar acids, thus facilitating mechanical se aration.
ferring to the drawing, it will be seen (heavy liquid) that therein there is illustrated diagrammatically a form of apparatus which can be employed in' the realizing of the invention.
In this apparatus there are shown con-' nected tanks A and B respectively, the latter of which is constructed so that substantially super-atmospheric pressure can be maintained while the operation therein is being carried out. I
' Thetank A has an outlet pipe C provided with valve controlled pipes D and E extending in opposite directions. The pipe D is controlled by pipe E is controlled by a hand-valve G. The t nk A has in the lower portion thereof a perforated pipe or coil H to which compressed air is supplied by the valve 'controlled pipe K. The perforated pipe or coil H is a part of the mechanism employed to effect an agitation of the liquid contents of the tank when .it is desired that the agitation be carried out. This mechanism in fact provides air agitation, as it is known in the arts, and may be referred to as air agitating means. With the valves F and G closed there is first placed in the tank A the reuired aqueous solution of caustic soda tNaOH) and this is followed by the insertion of the proper quantity of light oil, or middle oil, or both-of these oils, dependent upon whether the light oil, the middle oil or both of the oils is or are to be treated and until agitation is actually started the aqueous solution of caustic soda will remain at a hand-valve F while the the bottom-and the oil or oils will float on the top of this aqueous solution. \Vhether or not the light oil or the middle oil, or both of these oils is or are introduced is dependent upon the source from which the ultimate M or tar acids are. to be obtained. The oils and the solution in the tank are subjected to agitation by the air agitating means just described; they are also preferably heated as will hereinafter appear. As the reaction proceeds there is a tendency for heavy particles in the solution to settle to the bottom of the tank and therefore there is provided a pumping mechanism L in the form of an ejector having a suction pipe L extending from the lower portion of the tank and a delivery pipe L? emptying into the upper portion of the tank. As the pumping mechanism L is in the form of an ejector dependent for its operation upon steam flowing inwardly through the valve controlled pipe L and being delivered from the nozzle L of the ejector, said ejector can be employedto perform two functions: (a) to serve purely as a pump to convey or transfer the contents from the lower portion of the tank to the upper portion of the tank and (b) to serve as a means to supply heat during the period the reaction is taking place. It is desirable to maintain the solution hot While the reaction is taking place and it will be manifest that the ejector supplies this heat from the incoming steam. However, heat can be supplied in other ways, as by inserting an independent heating coil in the lower portion of the tank, or by providing a heating means exterior of the tank. Or, the heat could be supplied by air heated prior to passing through and from the coil H. In place of the ejector there could be'employed a purely mechanical pump. The pump or ejector L assists in the agitation, as is obvi-v ous, due to the transferring of the solution from the lower portion of the tank to the upper portion thereof. The reaction which takes place in this tank generally requires from 2 to 6 hours. Then the reaction is completed the contents of the tank are comprised of the non-acid solution which is relatively light and the sodium salt solution of the M or tar acids which is relatively heavy, the latter of which is marked on the drawing MONa. When the settling operation is completed a sharp line of demarkation exists, at X, between the non-acid solution and the MONa solution.
With no pressure in the tank B-viz. with no pressure substantially above-that of the atmospherethe MONa solution can be permitted to flow directly into the tank B by merely opening the valve G and in this way the mechanical separation of the MONa solution from the non-acid solution is completed. When the MONa solution is completely withdrawn the valve G is closed and thereafter by opening the valve F the nonacid solution can be withdrawn from th tank A.
The tank B has an outlet pipe 0 controlled by a hand-valve N. Within the tank B there is a mechanical agitator P. having a shaft extending through a' packing Q and suitably driven as by bevel gearing R. In the lower portion of the tank B there is a perforated pipe or coil S to which CO is supplied through a valve controlled pipe T. From the upper portion of the tank there extends a valve controlled pipe U. No substantial pressure exists in the tank B, as will hereinafter appear, when MONa. is being supplied -to the tank through pipe E. The MONa solution, as has been previously pointed out, is an aqueous solution. \Vhen the reaction is being carried out in tank B the CO is supplied under substantially super-atmospheric pressure, as by the compressor T through pipe T to the perforated pipe or coil' S. As the valve G in pipe E and valve in pipe U are closed during the time the reaction is taking place the CO is supplied in such a manner that the pressure within the tank is maintained at approximately 100 pounds per square inch. The packing Q is constructed so that 'said pressure can be maintained.
As has been reviously pointed out the water of the solution and the CO unite to form carbonic acid which in turn reacts with the MONa and thus there is a continuous absorption of the CO tending to reduce the pressure within the tank B. Therefore, CO must be supplied either continuously or intermittently to replace the CO used up by the reaction. The absorption of the CO tends to reduce the pressure and the CO is supplied not only to furnish the requisite O necessary for the chemical reaction but also to maintain the desired approximate 100 pounds pressure-substantially super-atmospheric pressurewhich expedites the reaction. During the time the reaction is taking place the agitator P is operating and as the CO is introduced under substantially super-atmospheric pressure through the perforated pipe or coil S it will be observed the CO is bubbled into the solution being treated within the tank B. The mechanical agitating and the bubblingwhich is also agitating-bring the CO into intimate contact with the MONa salt in the solution and with the pressure maintained substantially super-atmospheric the reaction within the tank B is effected in a relatively short space of time. If the CO supplied is derived from flue gases pumped under pressure into the tank B there will be a collection of inert gases in the upper portion of the tank B. These inert gases can be withdrawn intermittently or continuously by opening thevalve in the pi e U. When the reaction is completed the 60, supply is shut off, the agitator P is stopped, and the contents of the tank B are allowed to come to rest and settle. The M or tar acids (MOH) which have been freed as the result of the reaction are relatively light and they collect in the upper portion of the tank. The sodium carbonate (Na,CO
I which is absorbed in the water of the solution together form what may be called the sodium carbonate solution and this solution beingrelatively heavy settles or collects in the lower portion of the tank B. When the settling is completed there is a shar line of demarkation indicated by the line be tween the M or tar acids and the sodium carbonate solution. By opening the valve N the sodium carbonate solution is first withdrawn from the tank B; subsequently the M or tar acids can be withdrawn. In this manner the complete mechanical separation of the sodium carbonate solution and the M or tar acids can be readily effected and the M or tar acids recovered. The valve N is left open until the pressure within the tank B is reduced whereby a new supply of the MONa salt can be introduced into the tank B for treatment and the cycle of operations just described repeated.
As previously indicated an important feature of the present invention resides in the maintaining of the MONa solution under substantially super-atmospheric pressure while it is being treated with CO but it will be pointed out that the expression maintained at substantially super-atmospheric pressure as employed herein is not to be construed as necessarily meaning that the pressure must be maintained at some definite amount as, for example, 100 "pounds throughout the entire time reaction is taking place, but it is to be broadly construed as covering a situation wherein the pressure may vary somewhat during the reaction but one in which the ressure is maintained at all times substantlally super-atmospheric.
quired to accomplish said reaction is often as long as 24: hours or even longer.
According to my process the MOH acids can be recovered or reclaimedseparate d from the rest of the ingredients of a tar.
fraction or tar fractions as the case may be in much less time than by any process heretofore known or employed.
The improvements herein set forth are not limited to the mode of operation, or to the process, construction and arrangement shown and described for they may be employed in various ways, forms and modifications without departing from the spirit and scope of the .invention.
IVhat I claim is:
1. The obtaining of a tar acid from its salt by the method which consists in intimately bringing into contact with each other carbon dioxide and said salt while in the presence of water and under a sub stantially super-atmospheric pressure approximating 100 pounds per square inch, which super-atmospheric pressure is maintained until there results free tar acid, and
subsequently separating said free tar acid from the rest of the solution.
2. The obtaining of tar acids from their salt by the method which consists in intimately bring into contact with each other flue gas and said salt while in the presence of water and under a maintained pressure approaching 100 pounds per square inch until the tar acids .are liberated, and subsequently separating said tar acids from the rest of the solution.
3. In the obtaining of tar acids the method which consists in subjecting an aqueous solution of sodium salt of tar acids, when under approximately 100 pounds pressure per square inch in a closed receptacle, to the hubbling action of CO until tar acids are freed, and subsequently separating said tar acids from the rest of the solution.
4;. In the obtaining of tar acids the method which consists in subjecting an aqueous solution of sodium salt of tar acids, when under a maintained pressure in a closed receptacle and which pressure approximates 100 pounds per square inch, to the bubbling action of flue gas until there result tar acids in free form, and subsequently separating tar acids when in said free form from the rest of the solution, the inert gases which collect at the top of thereceptacle being withdrawn therefrom as desired.
This specification signed and witnessed this 7th day of February, A. D. 1918.
WALTER RUNGE. Signed in the resence of:
EDWIN A. ACKARD, G. MCGRANN.