US1551956A

US1551956A - Process of distilling wet combustible material

Info

Publication number: US1551956A
Application number: US715167A
Authority: US
Inventors: Hubmann Otto
Original assignee: American Lurgi Corp
Current assignee: American Lurgi Corp
Priority date: 1924-05-22
Filing date: 1924-05-22
Publication date: 1925-09-01
Anticipated expiration: 1942-09-01

Description

the distillation process differ materially in` all essential characteristics. Whereas the' the two operations do Patented Sept. l, 1925.

UNITED STATES PATENT OFFICE.

OTTO* HUBMA'NN, OF FRAN KFORT-ON-THE -MA1N, GERMANY, AssIGNoa ro AMERICAN Lunel conroRArIoN, or NEW Yoax, N. Y., A conronA'rIoN 0F NEW YORK.

rnocms or DISTILLI'N WET conuar'rsrlriarm` MATERIAL.

Application med May 22, 1924..l serial'Nn. 715,167.

To'all 'whom it may concern: f

Be it known that I, 'OTTO I-IUBMANN, a citizen of Germany', residingat Frankforton-theMain, Germany, in the county of Hesse-Nassau and State of Prussia, have invented certain new and useful Improvements in Processes of Distilling Wet Combustible Material, of which the a specification.

This invention relates tilling combustible siderable amounts combustible gases. p processes of this character distillation 1s particularly promoted if the material to distilled has been preliminarily well dried. The distillation of wet combustible material by means of combustible gases is well known.' 'It bustible materialto a operation for which the heat is furnished by the combustion of gases. However, up to the present time nobody seems to have realized the possibility of a combination of the two operations, as a unitary process in which the two operations favorably supplement leach other, for the drying process and following is to a process of dismaterials containing conof water, byl means of dr in process involves a purely physical chng taking place in the material at relatively low temperature, the distillation process involves principally chemical changes takin place at temperatures not lower than 400 It has been found that an intimate inter- .action of the drying operation'and the distilling operation may be 'so controlled that not only not interfere with each other but actually supplement each other towa d a common end..

For a full understanding of the invention,

' its principle of operation and its advan-` tagesZ reference is had to the accom anying drawing which is a more orless sc ematic representation of an apparatus by which the 'invention may be carriedout.

In the drawing 1 represents a drying chamf ber disposedV above and communicating throu h a passage 21 atr its bottom with .the

top o a still which provides for three Secbe tions in superposed relation. The uppermost section 2 is the distilling chamber proper, the r space of which has an outlet connected y means of ltpipez 2l with an exlas a regenerator residue or It is well known that in 410 leads to a gas admission -which is also old to subject wet compreliminary drying,

bottom of the distilling haustv device 12 preferably of the ventilator type. 'Ihe lower section 3 is provided space in which the sensible y stored up inthe coke or the `distillation in general may be abstracted by a stream of gas passed through it as will be more fully explained. Between the section 2 `and the section 3 is. provided a section 4 which serves the pur' ose to prevent a direct flow of gas from t e section 3 into the section 2. `Below the sectionf3 is a hopper portion 22 from which the material may be disch rged from the still through a gate 22.v f

The combustible gas is duced by a generator 5 heat ener preferably profrom which a pipe chamber 11 may form part of the still structure. The admission chamber communicates through two openings 1l and l1b with the interior of the still. One of the openings (.118) is on-a level defining in substance the chamber 2 -while the second openinglll?) is on a level defining in substance the top ofthe regenerator space 3. In other words, the openings referred to lie substantially in two planes between which is disposed the space 4.-.

The air for the gas generator 5 is furnished' by a blower 6 connected to yit by a pipe 7 containing a flow control device 7". A pipe 9 may be provided for passin steam linto the generator ltogether with t e air,

as indicated. 1-

The gaseous productsozt distillation, i. e., the gases and vapors drawn from the vapor space of the distilling chamber 2 by the exhaust device 12, are passed through a tar separator 13, of any suitable construction and the so purified gases are then conducted partly through a p-ipe 14 into the regenerator section 3 and partly thro h pipe 15' to the combustion chamber 17. Flow control devices 16 in

lines

14 and 15 serve the purpoise to vary at will the relative rates of as flow to there enerator 3 ustion' chamber l respectively.

A circulating system including aL blower 18 or the like and'pipes 18a and 18b leading into the bottom portion of the d ing chamr 1 and out of the upper portion thereof respectively, passes the hot products of combustion from the combustion chamber 17 upwardlythroughA the chargein the drying chamber. The combustion chamber 17 is 100 and the comr blower 18 to the bottom portion `of connected to the pipe 18EL generally to thefdiference between the rate ull working condition.

of gas flow into the drying chamber and the rate of flow out of it, which dierence in turn corresponds approximately to the rate at which the Water isV withdrawn from the charge.

From the blower 6 a ipe 8 leads directly to the combustion cham er 17 and by means of a suitable control device 8F* the rate of flow of air through this pipe may be determined at will.

The mode offloperation of the apparatus for carrying out the invention is as follows:

The drawing represents an apparatus in The material in sections 3 and 4 of the still is theisolid residue ofdistillation, i. e., coke or theV like, while the material in section 2 is undergoing distillation after previous treatment in the drying chamber 1. The-charge in the drying chamber represents wet combustible material, forinstance lignite, in a wet state as it is found in various places.

The gas generator 5fis'- assumed to be in operation and the flowy'control devices are adjusted to determine the 'lowof air to the generator 5 and the combustion chamber 17 'lhecontrol devices 16 in

pipes

14 and 15 are adjusted ,to divide the gas coming vlrom the tar separator 13 in delimte proportion, one part flowing to the-regenerator sec- .tit

tion 3 and the other to the combustion chamber 17. l l

The gas flowing into theregenerator section 3 passes through the hot coke to the lower opening (11b) communicatin with the gas admission chamber 11 and mingling with the gas coming from the generator 5 .enters the "distilling chamber 2 through the opening 11. n

The three sections of the still terminate at their lower ends in contracted portions which in conjunction with the wider upper portions of -the adjoining sections define abruptradial shoulders. The material passdownwardly through the still does .not the peripheral corner s aces below the shoulders so that periphera gas spaces are formed at the upper end of sections 3 and 4 and -at the upper end o the hopper 22.

The gas coming romthe pipe 14 thus may pass all around thev gasspace below secs tion 3 and then rising uniformly through the column of coke in section 3 may be col-l 'lected in the gas space below section 4 and then flow unimpeded to the lower opening Similarly the gas passing from the admission chamber 11 lthrough opening 11 It is apparent that the coupling of the drying operation with the distilling 0pcration can he varied within wide limits. vithout tirstexplaining the practical signiiicance ot' such variations,` it is obvious that by means of the valves 16 the gas coming from the separator 13 can be divided at will. Also the iow of air to the combustion chamber can be' regulated at will by means of the valve 8". By varying the rate of gas generation, or in other words the volume and composition and also the temperature ot' the combustible gas and'the rate of combustion and by Varying, on the other hand, the gas ow through the regenerator section, the cooperation of the drying process and th distilling process may be adjusted to the greatest advantage for they treatment of materials whose water contents may vary within wide limits.

The practical significance may be understood from the following:

The drying process as applied to combustible material containing muchwater requires considerably more heat-than the distilling process, in fact several times the amount necessaryfor the latter. This discrepancy in the expenditure otheat for the two operations is, of course, generally taken care of vin the invention by the fact thatvthe distillation is carried out by means of the sensible heat energy of the hot generator gas, while the drying is done by the heat of combustion of the gases derived from the distillation, .which include the generator gas. However, the general difference in the distribution of heat lis in many cases not suiicient. I n many instances the amount of heat required for-the distillation can not be furnished alone by the sensible heat of a volu`me of gas, the heat of combustion of which would be suiiicient Jfor the drying operation, especially --since the temperature of the distilling gas' must not exceed a 'definite limit. In such cases the drying operation may be carried on farther than was heretofore the practice` In this manner it l is possible to almost perfectly balance the system. On theone hand a relatively greater amount of heat may be'utilized for the drying operation, and, on the other hand, a relatively smaller amount of heat is made necessary for the distilling operation.l To more fully explain this phase, it may be mentioned that in the past wet lignite has been dehydrated to a point where the water the limit referredl tol practical to carry the dehydration below However, in the present invention where the sensible heat of the combustible gases and the heat of combustion of the gases coming from the still are correlated to a single unitary end,

a carrying forward of the drying operation may be highly advantageous and desirable.

In such cases an extension of the drying op-l eration means a shortening of the distilling operation and a balancing of the system in such a way that according to the law of minima, a minimum amount of heat energy is expended for the process as a whole. It

has been found that in extreme cases4 the dehydration of the material may be carried to a lower limit of 1- 2%.

In fact, practical results have shown that the correlationship ofthe drying operation and the distilling operation in the manner described not only leads often to an acceleration of the operation as a. whole, vbut'also brin s about a considerable reduction and simp ification of the apparatus.

In addition to that, it should be noted that a decrease in the quantity of gas lnecessary for the distillation means a decrease in velocity of the gas out of the distilling zone, which in turn has a beneficial influence upon the dust content of the tar.

In fact, it has been found that in order Y to obtain distillation products which represent a maximum both as to quality and as to quantity, the water content of the dried material shouldnot beabove a certain limit. In certain kinds of lignite this limit was about 2% at which the recovery of tar was most favorable.

In the above remarks, the discussion of the coupling of the drying operation and the distilling operation has dealt with the iiexibility of the system only in so-far as the difference between the sensible heat en! ergy of a combustible gas heated totemperatures suitable for4 distilling and the heat of combustion of the gasV coming from the still permits a general working comromise between the two phases, i. e.,l dry- 1n and distillingL n some cases itV may not be possible in the manner just discussed to adjust the two phases to obtain the best results. A

ready remedy is obtained bypassing gas throng the hot coke to abstract sensible heat energy therefrom and utilizing the heat thus recovered `for the distillation.

In .should be understood that the gas passed through the regenerating zone may be taken from any part of the system,"either directly from the gas generator or from the tar separator as previously described.v

By acceleration or by'retardation of the -flow of the gas through the regenerating zone it is possible to regulate the-volume and the temperature 0f the distilling gas bustion.

which is within wide limits. By means of a system for circulating gas throu h the regenerating zone, it is possible to nely regulate the amounts of heat to be transferred to the drying chamber and the distilling chamber, respectively.

The heating of the combustible gas may be effected in the gas generator itself or in any lother suitable manner. Instead of heating the gas by external means, it is, of course, possible to effect the heating by partial combustion,l as will be readily understood. It is thereby immaterial whether the gas coming from the generator or the gas coming out of the regenerator zone ora mixture thereof is subjected to partial com- The generator 5 has been referred to only in a general way, since there is considerable latitude in ythis direction. I prefer a gas generating plant includin means for heating the gases produced, o a type that permits variation within wide limits of the volume, quality and temperature of the gas.

The greater the adaptability of the plant in these respects, the greater is the flexibility of the system as a whole for the purpose of the invention.

In the foregoing special stress was laid upon the adaptability of the system to increase the transfer of heat to the distilling chamber. If it is found necessary or desirable to at any time eifect a relative increase in the transfer of heat into the drying chamber, 'it is only vnecessary to restrict the liow of gas to the'regenerating section 2 to cause a proportionatel larger flow of the gas to the combustion c amber 117.

Incase no separate source of power is available for doing the work involved in driving theblowers of the system, the gas of the gas generator or of the s ystem in general, may, of course, be used, 1n which case special provision is made therefor.

I claim:

1. In a roce of distilling wet'materi'al ecomposable by heat to form a combustible gas and a solid residue, involving the drying of said material to any certain degree and 'the distillation of the dried material, thesteps which consist inmoving said material v to be treated successively through a drying zone and a distilling zone,

maintaining a flow of combustible gas heated to distillin temperature through themagaseous products to effect t e drying of the material in the drying zone to sald certain. 1

degree.

material, the steps which consist in moving Vthe said material to be treated successively through a drying zone,a distilling zone and .a cooling zone, maintaining a flow of acombustible gas heated to distilling temperature through the material Vin the dlstilling zone; passing a gas through. the hotsoli'd residue of the distillation in the cooling zone and then through said material in said distilling zone, burning at least part of the gaseous' products evolved from said material in the distilling zone and `passing thev result- -ing products of combustion through the material in the drying zone, and regulating the volume,- temperature and composition 'ot said combustible gas passed through the material in the dryinzone, the volume of saidv gas passed throug the hot solid residue of the distillation-in the cooling zone and the burning of the said evolved gaseous products to eicctthe drying of the material in 4. Process as defined in claim 2 in Whichsaid gas passed through the hot solid distillation residue is a part of the gaseous products'of the distillation.

5.- Claim according to claim 1, in which part of the resulting gaseous products of distillation is returned and admixedto' the combustible gas entering the distillin'g zone.I f 6. Claim according to claim 1,v in which part of the resulting gaseous products of distillation is heated; and then returned and admixed to the combustible gasentering the d distilling zone.

In testimony whereof I aix my slgnature.: f OTTO