CA1078109A - Process and apparatus for recovery and reuse of ammonia in a liquid ammonia fabric treating system - Google Patents
Process and apparatus for recovery and reuse of ammonia in a liquid ammonia fabric treating systemInfo
- Publication number
- CA1078109A CA1078109A CA263,240A CA263240A CA1078109A CA 1078109 A CA1078109 A CA 1078109A CA 263240 A CA263240 A CA 263240A CA 1078109 A CA1078109 A CA 1078109A
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- CA
- Canada
- Prior art keywords
- ammonia
- liquid ammonia
- continuously
- water
- effluent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- D06M11/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising
- D06M11/58—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with nitrogen or compounds thereof, e.g. with nitrides
- D06M11/59—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with nitrogen or compounds thereof, e.g. with nitrides with ammonia; with complexes of organic amines with inorganic substances
- D06M11/61—Liquid ammonia
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- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Treatment Of Fiber Materials (AREA)
- Chemical Or Physical Treatment Of Fibers (AREA)
Abstract
PROCESS AND APPARATUS FOR RECOVERY
AND REUSE OF AMMONIA IN A LIQUID
AMMONIA FABRIC TREATING SYSTEM
Abstract of the Disclosure The disclosure is directed to a system for the recovery of spent ammonia, in connection with the processing of fabrics and the like with liquid ammonia, and concerns particularly the elimination from the recovered ammonia of undesired water.
Economic processing of fabrics by liquid ammonia requires recovery and reuse of substantial quantities of ammonia. In the course of processing, the ammonia unavoidably becomes contaminated with water. Separation of water from ammonia on a laboratory level or, in any kind of batch processing is a theoretically simple matter and can be coped with by conventional differential evapo-ration techniques, or otherwise. However, in a continuously operating processing line where large quantities of anhydrous liquid ammonia are being used as the treating medium, water accumulates rapidly, not only from the fabric being processed, but also from a certain inevitable amount of air leakage in the system, Because so much of any given increment of the treating medium must be recycled, as compared to that actually "used up"
in the treating process, water accumulates rapidly in the system and must be removed on a continuous basis. The specification discloses a unique and highly efficient procedure for removal of water by effecting condensation of water and ammonia vapors, con-stituting the process effluent, by feeding the effluent to a de-superheating vessel, where it is brought into direct contact with a body of low temperature liquid ammonia. This is done in con-junction with a preliminary low temperature condensation of the effluent in a non-contact heat exchange stage. The condensed body of liquid ammonia in the desuperheater vessel, including residual condensed water from the process effluent combined with re-lique-fied ammonia, forms the feed supply of liquid ammonia solution to the process. The condensed water, which in the new process constitutes a portion of the feed supply, is applied to the fabric being treated, along with the liquid ammonia. Typically, some of the water is carried away with the processed fabric as a con-stituent of its moisture content. The remainder, which is driven off as steam in the process, is recycled.
- 1a -
AND REUSE OF AMMONIA IN A LIQUID
AMMONIA FABRIC TREATING SYSTEM
Abstract of the Disclosure The disclosure is directed to a system for the recovery of spent ammonia, in connection with the processing of fabrics and the like with liquid ammonia, and concerns particularly the elimination from the recovered ammonia of undesired water.
Economic processing of fabrics by liquid ammonia requires recovery and reuse of substantial quantities of ammonia. In the course of processing, the ammonia unavoidably becomes contaminated with water. Separation of water from ammonia on a laboratory level or, in any kind of batch processing is a theoretically simple matter and can be coped with by conventional differential evapo-ration techniques, or otherwise. However, in a continuously operating processing line where large quantities of anhydrous liquid ammonia are being used as the treating medium, water accumulates rapidly, not only from the fabric being processed, but also from a certain inevitable amount of air leakage in the system, Because so much of any given increment of the treating medium must be recycled, as compared to that actually "used up"
in the treating process, water accumulates rapidly in the system and must be removed on a continuous basis. The specification discloses a unique and highly efficient procedure for removal of water by effecting condensation of water and ammonia vapors, con-stituting the process effluent, by feeding the effluent to a de-superheating vessel, where it is brought into direct contact with a body of low temperature liquid ammonia. This is done in con-junction with a preliminary low temperature condensation of the effluent in a non-contact heat exchange stage. The condensed body of liquid ammonia in the desuperheater vessel, including residual condensed water from the process effluent combined with re-lique-fied ammonia, forms the feed supply of liquid ammonia solution to the process. The condensed water, which in the new process constitutes a portion of the feed supply, is applied to the fabric being treated, along with the liquid ammonia. Typically, some of the water is carried away with the processed fabric as a con-stituent of its moisture content. The remainder, which is driven off as steam in the process, is recycled.
- 1a -
Description
~ ~ 7~ 0 ~
A key factor in the new process is that the re liquefied ammonia, instead of being sent directly back to the process, is directed into the desuperheater vessel9 there being combined with the condensed process ef~luent. The combined solution, cont~ining a minor fraction of condensed residual water is then fed back to the process. In this manner9 the to~al water ~raction in the pro-cess solution may be kept a satisfactorily low level3 typically on the order of two or three percent maximum) under extreme process conditions, and desirably much lower than tha~ under more favarable process conditions.
This application also is related to and constitutes an improvement over the subject màtter o~ the Briley et al patent No. 3~721,097, assigned to Cluett, Peabody ~ Co. a Inc., the assignee of this inventîon.
..
Back~round and Summary o the Xnvention Fabrics constructed at least in part of celluloslc mate-rials can be processed advantageously~by exposure to liquid ammonia, to achieve improvement in shrinkage resistance and to provide greater affinity of the fabric to other process chemicals, In accordance with known liquid ammonia treating techniques, ~he fabric may be exposed briefly to liquid ammonia solution~ as by immersion in a bath o~ the liquid. After a predetermined reaction time~ advantageously leSs than about nine seconds, the fabric is heated, to vaporize and drive off the ammonia and tenminate the ~ ~ 7 ~
reactions at a desired level J
In a typical liquid ammonia process, only a smaLl per-centage 9 (for example~ about 5%) of the ammonla is actually con~
sumed in the process reactions, or otherwlse lost. The baLance is in the fonm of ammonia vapor~ Because of th~ potentially hazardous and unpleasant nature of ammonia vapors, and also ~or obvious economical reasons, it is important ln a pract~cal liquid ammonia processing operation to recover9 for reliquefaction and reuse, the spent ammonia vapors~ Broadly speaking, this can be accomplished by withdrawlng the ammonia vapors from the fabric treatment chamber and compressing and condensing such vapors4 The condensed vapors are returned to a liquid ammonia storage tank for eventual reuse in the ~ystemO
One advantageous system for the recovery ~nd reusè of ammonia vapors is reflected in the aforementloned Briley et al patent No. 3972190970 In the system of the~Briley et:al patent~
the hot vapors from the proces~ing chamber are directed to a de-superheating vessel9 in which the vapors bubble through a bath of liquid ammonia, which may be at a ~emperature around ~28Fo The desuperheated gases are ~hen directed through appropriate compressing and condensing stages9 and the resulting liquefied ammonia is returned to a storage tank for ultimate reuse in the process~
~ hile ~he system of the Briley et al patent NoO 3~7219097, constituted an important advance in the art of ammonia reoovery, overall operating efficiencies are partially limite~ by gradual accumulation of water in the system~ Because water is h7ghly 8~
condensable m relation to the ammonia9 it is difficult to sepa~
rate from the liquid ammonia~ That is 9 ;n a high speed continuous processing lineg large quantities of treating medium in the fonm of anhydrous liquid ammonia are utilized and to a large extent must be continuously recycled~ Because the system inherently will accumulate water9 it must also be accomodated either on a batch basis requiring shutting down the line9 or on a con~inuou~ basisO
However, because the properties of ammonia and water are closely related their separation is difficult in ~he environment of a continuously operating processing line9 as opposed to conventional laboratory separation procedures. These water accumulations have necessitated the extraction and discarding from the process of water-diluted liquid ammonia from time to time~ Where circum~
stances permit9 such extractions can be used in fertilizer appli-cations. Otherwise, the mat~rial must be incinerated or otherwise properly disposed ofO
In accordance with the present invention, a unlque, high~
ly simplified, yet wholly effective procedure is provlded for con-tinuously eliminating water accumulations from the liquld ammonia recovery system without requiring the destruction or low grade utilization of significant quantities o~ liquid ammonia~ The procedure of the invention involves 9 in a liquid ammonia recovery system of the general type described in the Briley et al patent~
the unique procedure of deriv~ng.the liquld ammonia make~up flow to the treatment chamber from the retained Liquid body in the desuperheating vessel which receives the spent process vapors in cluding the residual water-fraction in the first place~ In a con~
tinuously operating process, this continuous outflow of condensed water in the make-up liquid prevents signifi~ant arcumulations of ~ ~ 7 ~
water in the desuperheatlng vessel and maintains the percentage of wa~er at a level Ofg for example9 2-3% under ~he most extreme process conditions and much less under more favorable conditions.
At those levels the water constitutes a relatively insignificant impurity.
In conjunctlon with the forego~ngg the fabric trea~ment process ideally is carried ou~ ln such a manner tha~9 when ~he fabric is heated after contact with the liquid ammonia, to term-inate ~he ammonia reactions~ the ammonia is vaporized 9 bu~ the water content of the fabric substantially remalns~ Thus, fabric emerging from the treatment chamber carries with it an increment of additional moisture9 which is thus permanently removed from the ammonia recovery system.
In some commercial applications of the process 9 it is not always practicable to control the process so as to avoid diso tilling off slgnificant percentages of the residual mois~ure con~
tent of the fabric. In such cases, the gaseous process effluent may carry excessively high percentages o~ moistureO Pursuan~ to another specific aspect of the invention~ such a gaseous process effluent, prior to being discharged into direct heat exchange con tact with liquid ammonia in the desuperheating vessel? is pre chilled by non contact heat exchange~ desirably utilizing liquid ammonia as the heat exchange medium~ With a heat exchange un~t of practical proportions, this can serve to precondense residual moisture out of the gaseous effluent d3wn to the two or three per-cent level.
Reg~rdless of the procedure utilized tv extract excess ~ ~7~
water from the continuous process system9 whether by mechanically conveying it out with the fabric and/or by condensing a portion of it and/or by utilizing some other technique, such as desi~cants, no practical technique for water removal will be 100% effective, Such being the case9 with conventional procedures, water will gradually accumulate ~n the desuperheater vessel~ either rapidly or slowly depending on the efficiency of the w~er extraction techniques, to the point where the desuperheating vesæel will be operating at greatly reduced ef~iciençy. However, pursuant to the invention, the liquid content o~ the desuperheater vessel, including condensed residual water, is continually fed back to the process chamber, and recycled through the various~water re-moval stages. The re-liquefied ammonia from the recovery system, ins~ead of being fed directly back to the processing chamber from its storage vessel7 is fed to the desuperheating vessel as make-up for the extracted watercontainingOsolution. Accordingly, the water content of the desuperheater-vessel is easily maintained at an adequately low level on a s~eady-s~ate basis~
A secondary, but nevertheless significant, advantagç of feeding re-l~quefied ammonia to the desuperheating vessel is that it is thereby simultaneously pre-chilled to its operating tempera-ture of -28F. (-33G) at a convenient location upstream of the processing chæmber without requiring a separate procedure for that purpose. As compared to feeding the re-liquefied ammonia directly tG the processing chamber where ~he eLevated temperature must be accommodated, the pre-chilling significantly reduces the energy requirements of ~he systPmO Thus, the procedure of the invention not only effectively eliminates accumulating water on a continuous, steady-state basis, but simultaneously achieves ~L~713~9 significant e~iciency improvements in the ammonia recovery system.
For a better understanding of the above and o~her fea-tures and advantages, reference should be made to the following detailed description and ~o the accompanying drawings.
Descri~tion of the_Drawings Fig. l is a simplified schematic rapresentation of a typical fonm of liquld ammonia ~abric processing system, lncorpo-rating an ammonia recovery syst.em in accordance with the invention.
Fig. 2 ~s a simplified schema~ic represen~ation of prin-cipaL components of an ammonia recovery liquefaction system ac-cording to the invention~
~ ,.
RefPrring now to the drawin~s~.and initial~y ~o Fig~ 1 thereo~, there is shown schematically an advantageous system for carrying.out a liquid~ammonia trea~men~ of a ~abric or yarn, for ex~mple. For purposes of this deseription, i~ will be assumed that.the material being pro~essed is a fabric web) comprised sub-stantially of ~ellulosic ~aterials. However, apart from the ability of ~he treated material to optimize process efficiencies by receiving and carrying away small quantities of water,~the specific nature of the ma~erial being ~reated is not signlfican~
~o the present i~ventionO
In Fig. L, a ~abrir web 10~ ~rom a suitable supply (not shown) passes over tension r-ontrol rollers 11 and is then direct--ed about one or more heated rollers 12, consti~u~in~ a pre~drying ~ - 7 -~, 1 ~ 7 ~ ~ 9 section, Passing over the series of pre drying rollers L2~ the fabric is heated sufficiently to drive of ~ excess moisture~ In this respect, incoming fabric typically may contain as much as 7-10% (by weight of the fabric) of moisture. The amount of mois-ture in the fabric may unduly inhibit the desired reactions o the liquid ammonia process, which nonmally should be carried out in a liquid ammonia solu~ion containing not more than about 10%
water. Although the weight of ammonia in relation to the weight of abric during the reactlon phase may vary wldely, a relation-ship o~ one-to~one (e~g,, one part by weight of thP ammonia solu-tion to one part by wêight of fabric) i9 not untypical. In such - 7a ~
:1078~C~9 cases, if -the incomin~ Eabric carries as much as 10% water, that amount of water will be present at the reaction site, and will constitute approxima~ely 10% of the ammonia solution. This is an undesirably high level, particularly where the ammonia solution itself may contain some water, as contemplated in the present invention. Accordingly, the pre-drying stage typical~y is con-trolled to drive off enouyh moisture from the fabric to leave a residual moisture content on the order of 3-5~ by weight of the fabric. Of course, if the incoming ~abric is sufficiently dry to be~in with, the pre-drying stage may be omitted.
Fabric leaving the pre-drying stage will be at an un- ~`
desirably elevated temperature and is thus cooled prior to enter-ing the liquid ammonia treatment chamber 13. Typically, suitable ;
fan or blower means 14 is disposed downstream of the pre-drying section, to direct streams of cooling air on the fabric and return it to near ambient temperature levels.
The pre-dried and cooled fabric, after passing over additional tension control rollers 15, enters the treatment cham- -ber 13 through a sealed opening 16. An advantageous form of seal for such opening is described and claimed in U.S. Patent 3,939,576 of Jackson Lawrence, for "Low Friction Pressure Seal ~
For Fabric Processing Chamber". Typically, the interior of -the chamber is maintained at a slightly negative pressure, rela-tive to ambient, and the entrance opening 16 is provided with a double seal. An intermediate chamber, between the double seals, is maintained at a slightly more negative pressure than the interior of the chamber, so that inevitable slight leakage of the seals will ~end to be directed .. . . ..
~ 7 ~
into the intermediate ~hamberO This minimizes leakage of ammonia vapors from the treatment chamber into the atmosphere. In a typo ical process, the main treatment chamber may be operated at a negative pressure of about 0.5" H20 while the intermediate cham-ber may be kept at a negative pressure of about 0.75" H20.
In the simpLified arrangement illustrated in ~ig L~ a processlng trough 17 is provided in the treatment chamber 13.
This trough, through appropriate controls (not shown, and forming no part of the invention) is supplied wlth liquid ammonia process-ing solution through an infeed line 18. The controls o~ thLs may include a float valve (not shown), for maintaining the processing liquid at an appropriate level in the trough After entering the processing chamber, the ~abric is guided into the trough L7 and thus immersed in the liquid ammonia solution which is at a temperature of about 28F. It is then directed through padding rollers 19, ~or extractian of excess processing solution~ then about a series of adjustable timing rollers 20. After a predetermined reaction time, the fabric is brought into contact with a source of heat9 which flash~s off the liquid ammoniaO In the illustrated system, a pair of Palmer~type dryer units 21, 22 are provided. These include large heated drums 23 about which a confining blanket 24 is trained. For practical purposes, the ammonia react~ons are substantially diminished soon after thc initial contact between the fabric and the first dryer drum. To advantage3 the time interval between initial immersion in the liquid ammonia and initial contact with the first dryer drum is controlled to be within the range of 0 6 seconds to 9 secondsO This can be effectlvely controlled by ~ 9 ~
:~71 3~9 regulation of the length o~ travel between the trough 17 and the first dryer unit ~19 as by adjustment of the rollers 20 to lengthen or shorten the path of the web9 as may be appropriate, However, except as relates to the control of water in the ~abric and in the processing solution and as relates to the controL of the operation of ~he dryer units 21, 229 specific process condi~ions do not fonm a part of this invention.
A~ter leaving ~he second dryer stage 22, the fabric leaves the main treatment chamber 13 through a discharge opening 25, This opening9 like the entrance opening 169 advantageously is provided with a double seal with an intenmediate chamber main~
tained at a slightly more negative pressure than the treatmen~
chamber itseLfO
Fabric leaving the ma~n treatment chamber 139 advantage~
ously may be directed through a steam chamber 269 after which the fabric may be conveyed away to a folder or batcher9 for example.
In ~he processing of fabric in the main treatment chamber 13~ only about 5% of the liquid ~mmonia supplied to the trough 15 is actually consumed~ The remainder is flashed off as ammonia vapor. These vapors are not only potentially hazardous9 but the re-use thereof is economically important in a continuous commercial pro~ess~ Heretofore9 recovery of the ammonia vapors has been carried out by withdrawing vapors from the treatment chamber9 and compressing and condensing the vapors~ Considerable amounts of air are normally contained in the withdrawn gases9 but air is easily separated from the ammonia because of the relative non-condensability of air~ The withdrawn gases also include:quantities - 10 ~ ', ~ ~ 7 ~ ~ O ~
o~ water, which continuaLly enter the process because of the basic moisture content of the fabric and also of the incoming air which, notwithstand;ng the efficiencies of the entrance and exit sealsg is present in certain amounts in the interstices of the fabrlc and en~ers with the fabricO Such amounts of wa~er have9 in the past9 proven difficult to remove as noted ~bove9 necessitating occasional discarding of quantities of the diLuted liquld ammonia9 or its use as a low grade materlal such as in fertilizer appl~
cations~ The process of the present invention is directed to the recovery of the spent ammonia in a manner that enables the water to be easily and effectively removed on a continuous basis a SO
that the process react~ons are not inhibited by excessive water in solution with the otherwise relatively pure anhydrous liquid ammonia, and so that maximum utilization of the liquid ammonia in the processing operation may be real~zed.
In the simplified schematic representatlon of Figo 1~ a surtion line 27 Leads from the main treatment chamber 13 for effecting eontinual withdrawal of gases from the interior of the chamber. These gases are dire¢ted initlaLly to a recovery sec~
tion, generally designated by the numeral 28 in Fig. l, in which the gases are processed to compress and condense the liquid ~mmonia and to separate airO A liquid ammonia storage vessel 29 is pro~
vided for temporary contai~ment of the reco~ered liquid ammonia.
As will be~described in greater detail with respect to Figs~ 2 9 the infeed line 189 through wh~ch the processing trough 17 is supplied, is not dir~ctly connected wi~h ~he storage vessel 299 but rather leads from the recovery section ~8~ The stored liquld ammonia is first directed ~rom the vessel 29 back into the re covery system9 where ~t is utilized in a manner to be described~
and then is directed to ~he processing trough 17 along with an increment of water extracted from the recovered gases~
In accordance w;th conventional practice9 air separated from the recovery system is direct to an incinerator or other disposal facility 300 Likewise ? the mixture of air and steam from the steam chamber 269 containing some residual ammonia gas, is directed through a suction lirle 31 to the disposal ~acllity.
Because of the relatively small amoun~s o ammonia ln these gases, it is considered uneconomical to attempt to recover lto Referring now ~o ~he schematic diagram of Fig. 2a the suction line 27 is shown to lead from the treatment chamber 13 to a non~contact heat exchanger 32 which may be of a shell and tube type. The withdrawn gases, comprising.predominantly amm~nia gas9 but also containing quantities of air and water vapor, may be passed throu~h the shell side of the exchanger9 while cooling medi~m ib-flowed in the tube side of the exchanger~
To advantage9 the non~contact heat exchanger-32 has two heat exchange stages constituting cooling and chilling stages~
In the cooling.stage, water may be u~ilized as the heat exchange medium, being flowed through lines 33~ 34~ In this stage3 gas~s leaving the treatment chamber 13 at a temperature of 9 typically9 about 150F., are pre-cooled in the wa~er section of the exchanger to about:90F7 In the second stage of the heat exchanger9 liquid ammonia desirably is u~ilized as the non-contact heat exchange medi~m. The liquid ammonia is supplied through l mes 33a9 34a9 being supplied at a temperatur~ of around ~8F~ a~d serving to chill the effluent process gases from the .~re~cooled temperature ~78~119 of 90 to9 say9 about ~21F!
Pursuant to one aspect of the mvention9 the low tempera-ture chilling of the effluent gases in the second stage of the heat exchanger 32 serves to condense out of the gas a substantlal fraction of the residual moisture contentO ThLs condensed wa~er fraction can be drained of~ at 32a and collected for ~urther pro-cesslng or low grade utilization~
Because of ~he extremely high affinity of ~mmonia for water, the water fraction condensed in the heat exchanger 32 will inevitably absorb some ammonia, so that the condensate extracted at 32a typically is around a fifty percent mixture of water and ammonia. The overall amounts of collected cond~nsate are gener-ally quite small. Thus, in a typical commer~;al process handling, say, 3000 pounds o~ fabric per kour and thus requiring a process feed of liquid ammonia solution of around 2500 to 3000 pounds per hour3 the outtake of condensate may be on the order of eight to ten gallons per hour, approximately half of which is ammonia~
Insofar as the outtake quantity of ammonia At this stage may be~
come economically significant in a proeess of sufficiently high overall volume, at least somP of the ammonia content of the con- :
densate could be recovered without great diffieulty~
The chilled gases from the heat exchanger 32~ are di~
rected into a desuperhea~ing vessel 36 conta m ing a body 37 of liquid ammonia9 In the process of the invention9 the de~uper~
heating:vessel is maintained at a sl~ghtly negative pressure9 and thus the,-body 37 of liquid ammonla therein is maintained at a temperature on the order o~ ~28F., (or slightly higherg depend~
- 13-~
7~
ing primarily on the total water fraction)~ The incoming process gases can be discharged directly into the lower portion of the de-superheating vessel 36 and bubbled upward through the cold liquid ammonia~ Alternatively, the process gases may be sprayed with liquid ammonia. In either case, the direct contact heat exchange serves to remove superheat from the ammonla gases 9 with the cooled gases acc~mulating in the upper portion 38 of the vessel, along with additional gases which are 1ashed o~f from the liquid itself, in order to maintain its low temperature and liquid phase.
A suction line 39 connect~ the upper portion.of the de superheating vessel 36 with the suction side of a compressor 40 driven by a motor 41~ In the compressor~ the gases comprising principally desuperheated ammonia gas together with alr~ may be compressed to a pressure o~, for exampleg about 180 psigO The compressed gases are heated substantially by the compression and leave the compressor through a high pressure llne 42g at a tempera ture of about 100F O The high pressure l me 42 leads to the shell side of a shell and tube condenser~heat ex~hanger 43~ cooled by water supplied to the tube side by inlet and outlet lines 449 45 Liquid ammonia condensate from the condenser 43~ now at a temperature of about 95F~, is flowed throu~h a high pressure line 46 into the storage and retention vesseL 29u Uncondensed vapors.from the condenseroheat ~xchanger 439 are taken off through a line 47 and directed into a pur~ing vessel 489 in which the un-condensed vapors are fLowed in non-contact heat ex~hange relation-ship with liquid ammonia at Low temperature (typi~ally ~28Fo) and caused to condense~ The condensed material from the purge v~ssel 48, is flowed through a:.llne 49 into the desuperheating ~ ~4 ~
1~78~'3 vessel 36, where the liquid fraction of such mater~al adds to the body of liquid ammonia9 and the contained gaseous fraction, if any, is bubbled through the liquid ammonia and recycled~
Liquid ammonia ~or cooling the purge vessel 48 is drawn from the retention vessel 299 passed throu~h a suitable expanslon valve 50 and directed into the tube side of ~he purge vessel, which typically is a sheLl and tube type heat exchange vessel~
After passing through the tube side o~ the purge vessel 489 the liquid ammonia may be directed through an outlet line Sl and combined with the condensate flowing in the line 499 to the de~
superheating vessel.
In accordance with a significant aspect of the i~ventlon, the liquid ammonia requirements of the process are supplied to th~
main treatment chamber 139 entirely or in subst~ntial part through a l~ne 18 which leads, not directly from the storage vessel 299 but rather from the de~upe~heating vessel 36 whi~h received the efflu~nt in the first place. To this end9 the vessel 36 has an outlet line 52~ leading to the intake side of a suitable pump 53 which dischar~es through a ~ontrol valve means 54 into the line 18a connected to the processing trough 17. To advantage9 the de~
superheating vessel 36 may be provided wi~h appropriate liquid level sensing elements 55, 56, establishing upper and L~wer limits for the level of liquid ammonia thereln. A valve 579 in a liquid ammonia supply line 58 from the high pressure suppLy ve~sel 29, may be controlled by the sensors 559 569 to admit liquid ammonia into the desuperheater vessel, as necessary9 to maintain the de~
sired level thereinO
As will be understood~ ~he fresh9 relatively pure an~
hydrous liquid ~ 15 ~ ~ 7 ~
ammonia admitted into the desuperheating vessel 36 from the storage vessel 29 perfonms several functions. First, the liquid may be directed to the desuperheating vessel 36 while still at a relatively high temperature of around 95F~ for example, and at a relatively high pressure of around 180 psig~ Since the liquid body within the desuperheating vesseL i5 in equilLbrium at a slightly negative pressure and at a temperature o~ around -28F.
a certain amount of the incoming, ~resh liquid ammonia is initi-ally 1ashed of to provide sel~-cooling to the equilibrium con-ditions. In a typical process~ as much as 25% by weight of the liquid ammonia rom the storage vessel is flashed off as gas in order to effect self-cooling to -28F~ of the remaining 75%O
Significant advantages are realized, in the process of the invention, by effecting self~cooling of the re~liquefied ammonia at the desuperheater stage~ rather than in the treatment chamber 13, as would be the case if the re~liquefied ammonia were taken directly from the storage vessel 29 to ~he treatment chamber.
As will be appreciated, large volumes of ammonia are required for the self-coollng action and, where sueh volum~s are released with~
in the treatment chamber 13, as in the past, this serves to in~
crease the energy requiremen~s of the heating section of the pro-cessing chamber and correspondingly to increase the cooling re-quirements of the ammonia recovery system~
In the operation of the system of Fig. 29 liquid ammonia, rontaining a mlnor fraction of water, is directed through the lines 52, 18 into the processing chamber 13, and is supplied direc~ly to the trough 17. The fabric web 10 is continuously advanced in~o and through the processing chamber at a predetanmined ~ 16 -1~7~3~L09 speed. As the fabric en~ers the chamber, it is immersed in ~he trough 17 and becomes saturated with the liquid ammonia solution.
When the processing equipment is in a steady-state condition, the chamber 13 is fully saturated with ammonia vapors so that, when the fabric emerges from the trough 17 and travels to the point o its initial contact wlth the dryer unit 21~ lt remains e~fectively saturated with the liquid ammonia. During thl~ ln~erval, the principal desired reactLons between the ammonla and the ~abric occur Soon after the ~abric is flashed o~f to substantialLy tenminate the reaction, and the balance is substantially removed as the fabric travels over the dryer units 21, 22.
Although the relationship of fabric processed to ammonia solution utilized may vary widely with different fabrics, a reW
lationship of one pound liquid ~mmonia infeed to one;pound of fabric infeed is not untypical and will be assumed for the pur-poses of illustration herein. Thusg for each pound of fabric e~tering the chamber, a pound of the liquid ammonia solu~ion is ~bsorbed ~rom the trough 17 and carried away with the moving fabric, wi~h approximately 95% of tha~ ~mount being 1ashed by the dryer units 21, 22. Thus, for each pound of fabric processed, nearly a pound of spent gases must be withdrawn from the chamber 13.
Because the incoming fabric conveys trappe~ air within its interstices, and because that air inherently will contain som moisture, the atmQsphere within the chamber 13 necessarily will become partly dilu~ed wi~h air and its mois~ureO This will occur regar~less of the ef~ica~y of the seals at the entrance and exit openings. When this ammonia~rich mixture of gases is withdra~ from the chamber and bubbled through the desuperheating vessel 36, the moisture fraction in the gases readily condenses in the body 37 of liquid ammonia, which is at approximately -28F.
In addition, for some processing operations, an additional mois-ture fraction may be driven off of the fabric by the heat of the dryers 21,22. Unless properly dealt with, these water fractions will accumulate in the vessel 36, causing the temperature in the bath 37 eo progressively rise until it is no longer serving its intended function, and must be e~tracted and discarded an/or used in low grade application. In accordance with the invention, however, the water-containing liquid ammonia in the desuperheating vessel 36, is constantly extracted through the line 52 and uti~
lized as the make-up feed to the impregnating trough 17.
As an integral part of the process of the invention, pro-vision is made for the constant removal of water from the process, on a convenient and economical basis. Although the particular technique utilized for water extraction is not critical to the basic process of the invention) it is of~rourse critical that some means be provided for water removal. To greatest advantage, and as one of the specific aspects of the in~ention, water is most convenient-ly removed by a combination of techniques, including mechanically conveying a water fraction out with the processed fabrics, where practicable and condensing a water fraction out of the hot ef-fluent gases extracted from the treatment chamber~ Thus, where processing conditions permit, it is advantageous to so control the time-temperature relationships of the heating section as to drive off primarily the ammonia fraction while substantially re-training the wa~er fraction in the fabric. By this means, the -fabric can be caused to leave the process with a slightly gxeater ~' :.
7 ~ ~ g moisture content than when it enters, resulting in a net out~ake of water from the processing system.
Since not all fabrics and not all proc~ssing conditions admit of optimum control of the heating sec~ions, secondary pro-vision is made for pre-cooling and then chiLli~g ~he hot ef~luent gases from the process, in order to condense out at least part of the water fraction in the spent gasesO By pre-chilling the spent gases down to about -21F., for example, which ls readily accomplished in a non-contact heat exchanger of practical propor-tiQns, using available liquid ammonia as the chilling agent, the water fraction may easily be reduced down to 2~3%. By thus pro-viding for alternative water removal by fabric conveyance or by condensation from the hot effluent gas, optimum process efficien-cies may be realized. Where the nature of the fabric-and the particular procesaing admits, the heating stage may be oo~trolled to ach~eve a net outflow of water on the fabric itself. H~wever, where the process cannot be operated in this ideal manner, the resulting high moisture content of ~he hot effLuent gases will be significantLy reduced by chilling in the non-contact heat ex-changer 32 The system of the invention is uniquely effe tive in eliminating the build-up of undesired quantities of water in the systPm and~ at the same t~me, ~ignificantly improving the thenmo-dynamic efficien~y of the system, by drawing upon the ~ody o~
water-containing liquid ammonia solut~on in the desuperheating vessel for ~he supply o~ process solution. By feeding this solu-tion back ~nto the process, the water fraction, which is inherent-ly going to be present in ~he recovexed process gases, ls - 19 ~
~ ~ ~ 8~ ~ 9 prevented from accumulating to an undesired level and can be re-moved at a convenien~ stage of the process.
Under ideal condi~ions of process operation, the steady-state residual water content in the desuperhea~er vessel may be maintained at ex~remely low level. Even under adverse conditions, the water content of the desuperheating vessel may be easily kept at levels (2-3% or less) which enabLes both the primary treating process itself, and also the recovery sys~em, ~o be operated at highly efficient levels.
One of ~he signiflcant dditional advantages of the uni-que process is the improved thenmodynamic efficiency which results from feeding the re-liquefied ammonia into the desuperheating ves-sel, rather than directly into the process chamber 13~ Thus, the re-liquefied ammonia in the starage vessel 29 is both at high pressure and at a relatlvely elevated temperatureO At the time of use, the liquid ammonia must be brought to equilibrium at sub-stantially atmospheric pressure (actually slLghtly below atmos-pheric) and at an equilibrium temperature of about -28F~ In order to achieve this equilibrium ~tate, substantial percentages of the re-liquefied ammonia are flashed off as gas9 When this is caused to occur at the desuperheating vessel~ these substantial quantities o~ flash~d-o~f gases are simply recycled throu~l the recovery s~stem, compressed and re-liquefied~ I~, on the other hand~ the gases are flashed off in the treatment chamber 13, as according to prior practice, the flashed-off gases are returned to the recovery system only after being exposed to substantial heat within the treatment chamber~ As will be appre~iated, the heat which goPs mto elevating the temperature of that fraction - 20 ~-~ ~ 8 1 ~ ~
of gas which is flashed off merely to bring the liquid ~mmonia to an equilibrium condition represents a waste of heat energy in the he~ting section of the processu Likewise, in order to re~
quefy and recover this gas~ the heat ~ust be removed therefrom, which serves to increase the working lo~d on the compressor~ Thus, in the new process, by deriving the process ~eed ~rom ~he desuper-heating vessel, and ~tilizlng the re-lique~ied ammonia as make~up feed to the vessel and not directly to the process chamber, not only is the water conten~ o the system stabilized at an appropri-ate equilibrium level, bu~ significant energy efficiencies are realized.
The system of the invent10n is uniqueLy effective in eliminating undesired water from the recir~ulating ammonia system~
This is of criti~al importance~ ~n a practical, commercial system9 because there is almost a twenty~to~one ratio between the amounts of æmmonia recycled and the ~amount basically consumed ~n the pro-cess, such that effective reclaiming te~hniq~es are vitalq Here-tofore, such reclaiming techniques have been severely limited by the practical difficulties ln ridding:the~system of water which unavoidably en~ers the system.
The process and system of the present invention, operate on the ba~is of condensing out the water frac~ion a~.an early stage in the recovery processJ by dire~t GOntaCt with a body cf cold liquid ammonia,.with or-without a prior non contact conden~
sation stage, to provide the make~up supply to ~he processl The condensed water in the desuperheating vessel is thus fed dirçctly back into the process as qui~kly as it enters~.enabling a steady stae ~evel to be rea hed which~ experience ha$ shown7 is ~7~1~g suficiently low as to ha~e insignificant effects upon the process reactions. Thus, while as much as LO% moisture in th~ liquid ammonia solution may substantially inhibit the desired reactions, the water fraction introduced into the processing solutio~ by the system of the invention, represents a rela~ively insignificant increment. In any case, prov~slon may be made ~or predrying the incoming fabric, not only ~o minimize incoming moisture content, but aLso, under some conditions, enabling a water fraction to be removed by the fabric. Thus, in An ldeal process 9 fabrlc may enter the process with a mois~ure content on the order of 5%, be subjected to the desired liquid ~mmonia reactions, and leave the process with a moisture content on the order, for example, 5.1%~
By this means, the fabric itself serves as a continuous means of extracting water from the ammon~a reco~ry system, permitting the system to operate on an ex~remely efficient basis~ with a minimum wastage or low grad~ utilization of the recovered material. Where such ideal conditions are not realizeable, other means, s~ch as non-contact condensation of spent gases~are utilized to extract a water fraction.
It should be understood, of course, that the form of the invention herein illustrated and described is ~nte~ded to be representative only, as certain changes may be made therein with-out departing~from the clear teachings of the disclosure. Ac-cordingly, reference should be made to the following appended claims in detenmining the full srope of the invention.
~- 22 r
A key factor in the new process is that the re liquefied ammonia, instead of being sent directly back to the process, is directed into the desuperheater vessel9 there being combined with the condensed process ef~luent. The combined solution, cont~ining a minor fraction of condensed residual water is then fed back to the process. In this manner9 the to~al water ~raction in the pro-cess solution may be kept a satisfactorily low level3 typically on the order of two or three percent maximum) under extreme process conditions, and desirably much lower than tha~ under more favarable process conditions.
This application also is related to and constitutes an improvement over the subject màtter o~ the Briley et al patent No. 3~721,097, assigned to Cluett, Peabody ~ Co. a Inc., the assignee of this inventîon.
..
Back~round and Summary o the Xnvention Fabrics constructed at least in part of celluloslc mate-rials can be processed advantageously~by exposure to liquid ammonia, to achieve improvement in shrinkage resistance and to provide greater affinity of the fabric to other process chemicals, In accordance with known liquid ammonia treating techniques, ~he fabric may be exposed briefly to liquid ammonia solution~ as by immersion in a bath o~ the liquid. After a predetermined reaction time~ advantageously leSs than about nine seconds, the fabric is heated, to vaporize and drive off the ammonia and tenminate the ~ ~ 7 ~
reactions at a desired level J
In a typical liquid ammonia process, only a smaLl per-centage 9 (for example~ about 5%) of the ammonla is actually con~
sumed in the process reactions, or otherwlse lost. The baLance is in the fonm of ammonia vapor~ Because of th~ potentially hazardous and unpleasant nature of ammonia vapors, and also ~or obvious economical reasons, it is important ln a pract~cal liquid ammonia processing operation to recover9 for reliquefaction and reuse, the spent ammonia vapors~ Broadly speaking, this can be accomplished by withdrawlng the ammonia vapors from the fabric treatment chamber and compressing and condensing such vapors4 The condensed vapors are returned to a liquid ammonia storage tank for eventual reuse in the ~ystemO
One advantageous system for the recovery ~nd reusè of ammonia vapors is reflected in the aforementloned Briley et al patent No. 3972190970 In the system of the~Briley et:al patent~
the hot vapors from the proces~ing chamber are directed to a de-superheating vessel9 in which the vapors bubble through a bath of liquid ammonia, which may be at a ~emperature around ~28Fo The desuperheated gases are ~hen directed through appropriate compressing and condensing stages9 and the resulting liquefied ammonia is returned to a storage tank for ultimate reuse in the process~
~ hile ~he system of the Briley et al patent NoO 3~7219097, constituted an important advance in the art of ammonia reoovery, overall operating efficiencies are partially limite~ by gradual accumulation of water in the system~ Because water is h7ghly 8~
condensable m relation to the ammonia9 it is difficult to sepa~
rate from the liquid ammonia~ That is 9 ;n a high speed continuous processing lineg large quantities of treating medium in the fonm of anhydrous liquid ammonia are utilized and to a large extent must be continuously recycled~ Because the system inherently will accumulate water9 it must also be accomodated either on a batch basis requiring shutting down the line9 or on a con~inuou~ basisO
However, because the properties of ammonia and water are closely related their separation is difficult in ~he environment of a continuously operating processing line9 as opposed to conventional laboratory separation procedures. These water accumulations have necessitated the extraction and discarding from the process of water-diluted liquid ammonia from time to time~ Where circum~
stances permit9 such extractions can be used in fertilizer appli-cations. Otherwise, the mat~rial must be incinerated or otherwise properly disposed ofO
In accordance with the present invention, a unlque, high~
ly simplified, yet wholly effective procedure is provlded for con-tinuously eliminating water accumulations from the liquld ammonia recovery system without requiring the destruction or low grade utilization of significant quantities o~ liquid ammonia~ The procedure of the invention involves 9 in a liquid ammonia recovery system of the general type described in the Briley et al patent~
the unique procedure of deriv~ng.the liquld ammonia make~up flow to the treatment chamber from the retained Liquid body in the desuperheating vessel which receives the spent process vapors in cluding the residual water-fraction in the first place~ In a con~
tinuously operating process, this continuous outflow of condensed water in the make-up liquid prevents signifi~ant arcumulations of ~ ~ 7 ~
water in the desuperheatlng vessel and maintains the percentage of wa~er at a level Ofg for example9 2-3% under ~he most extreme process conditions and much less under more favorable conditions.
At those levels the water constitutes a relatively insignificant impurity.
In conjunctlon with the forego~ngg the fabric trea~ment process ideally is carried ou~ ln such a manner tha~9 when ~he fabric is heated after contact with the liquid ammonia, to term-inate ~he ammonia reactions~ the ammonia is vaporized 9 bu~ the water content of the fabric substantially remalns~ Thus, fabric emerging from the treatment chamber carries with it an increment of additional moisture9 which is thus permanently removed from the ammonia recovery system.
In some commercial applications of the process 9 it is not always practicable to control the process so as to avoid diso tilling off slgnificant percentages of the residual mois~ure con~
tent of the fabric. In such cases, the gaseous process effluent may carry excessively high percentages o~ moistureO Pursuan~ to another specific aspect of the invention~ such a gaseous process effluent, prior to being discharged into direct heat exchange con tact with liquid ammonia in the desuperheating vessel? is pre chilled by non contact heat exchange~ desirably utilizing liquid ammonia as the heat exchange medium~ With a heat exchange un~t of practical proportions, this can serve to precondense residual moisture out of the gaseous effluent d3wn to the two or three per-cent level.
Reg~rdless of the procedure utilized tv extract excess ~ ~7~
water from the continuous process system9 whether by mechanically conveying it out with the fabric and/or by condensing a portion of it and/or by utilizing some other technique, such as desi~cants, no practical technique for water removal will be 100% effective, Such being the case9 with conventional procedures, water will gradually accumulate ~n the desuperheater vessel~ either rapidly or slowly depending on the efficiency of the w~er extraction techniques, to the point where the desuperheating vesæel will be operating at greatly reduced ef~iciençy. However, pursuant to the invention, the liquid content o~ the desuperheater vessel, including condensed residual water, is continually fed back to the process chamber, and recycled through the various~water re-moval stages. The re-liquefied ammonia from the recovery system, ins~ead of being fed directly back to the processing chamber from its storage vessel7 is fed to the desuperheating vessel as make-up for the extracted watercontainingOsolution. Accordingly, the water content of the desuperheater-vessel is easily maintained at an adequately low level on a s~eady-s~ate basis~
A secondary, but nevertheless significant, advantagç of feeding re-l~quefied ammonia to the desuperheating vessel is that it is thereby simultaneously pre-chilled to its operating tempera-ture of -28F. (-33G) at a convenient location upstream of the processing chæmber without requiring a separate procedure for that purpose. As compared to feeding the re-liquefied ammonia directly tG the processing chamber where ~he eLevated temperature must be accommodated, the pre-chilling significantly reduces the energy requirements of ~he systPmO Thus, the procedure of the invention not only effectively eliminates accumulating water on a continuous, steady-state basis, but simultaneously achieves ~L~713~9 significant e~iciency improvements in the ammonia recovery system.
For a better understanding of the above and o~her fea-tures and advantages, reference should be made to the following detailed description and ~o the accompanying drawings.
Descri~tion of the_Drawings Fig. l is a simplified schematic rapresentation of a typical fonm of liquld ammonia ~abric processing system, lncorpo-rating an ammonia recovery syst.em in accordance with the invention.
Fig. 2 ~s a simplified schema~ic represen~ation of prin-cipaL components of an ammonia recovery liquefaction system ac-cording to the invention~
~ ,.
RefPrring now to the drawin~s~.and initial~y ~o Fig~ 1 thereo~, there is shown schematically an advantageous system for carrying.out a liquid~ammonia trea~men~ of a ~abric or yarn, for ex~mple. For purposes of this deseription, i~ will be assumed that.the material being pro~essed is a fabric web) comprised sub-stantially of ~ellulosic ~aterials. However, apart from the ability of ~he treated material to optimize process efficiencies by receiving and carrying away small quantities of water,~the specific nature of the ma~erial being ~reated is not signlfican~
~o the present i~ventionO
In Fig. L, a ~abrir web 10~ ~rom a suitable supply (not shown) passes over tension r-ontrol rollers 11 and is then direct--ed about one or more heated rollers 12, consti~u~in~ a pre~drying ~ - 7 -~, 1 ~ 7 ~ ~ 9 section, Passing over the series of pre drying rollers L2~ the fabric is heated sufficiently to drive of ~ excess moisture~ In this respect, incoming fabric typically may contain as much as 7-10% (by weight of the fabric) of moisture. The amount of mois-ture in the fabric may unduly inhibit the desired reactions o the liquid ammonia process, which nonmally should be carried out in a liquid ammonia solu~ion containing not more than about 10%
water. Although the weight of ammonia in relation to the weight of abric during the reactlon phase may vary wldely, a relation-ship o~ one-to~one (e~g,, one part by weight of thP ammonia solu-tion to one part by wêight of fabric) i9 not untypical. In such - 7a ~
:1078~C~9 cases, if -the incomin~ Eabric carries as much as 10% water, that amount of water will be present at the reaction site, and will constitute approxima~ely 10% of the ammonia solution. This is an undesirably high level, particularly where the ammonia solution itself may contain some water, as contemplated in the present invention. Accordingly, the pre-drying stage typical~y is con-trolled to drive off enouyh moisture from the fabric to leave a residual moisture content on the order of 3-5~ by weight of the fabric. Of course, if the incoming ~abric is sufficiently dry to be~in with, the pre-drying stage may be omitted.
Fabric leaving the pre-drying stage will be at an un- ~`
desirably elevated temperature and is thus cooled prior to enter-ing the liquid ammonia treatment chamber 13. Typically, suitable ;
fan or blower means 14 is disposed downstream of the pre-drying section, to direct streams of cooling air on the fabric and return it to near ambient temperature levels.
The pre-dried and cooled fabric, after passing over additional tension control rollers 15, enters the treatment cham- -ber 13 through a sealed opening 16. An advantageous form of seal for such opening is described and claimed in U.S. Patent 3,939,576 of Jackson Lawrence, for "Low Friction Pressure Seal ~
For Fabric Processing Chamber". Typically, the interior of -the chamber is maintained at a slightly negative pressure, rela-tive to ambient, and the entrance opening 16 is provided with a double seal. An intermediate chamber, between the double seals, is maintained at a slightly more negative pressure than the interior of the chamber, so that inevitable slight leakage of the seals will ~end to be directed .. . . ..
~ 7 ~
into the intermediate ~hamberO This minimizes leakage of ammonia vapors from the treatment chamber into the atmosphere. In a typo ical process, the main treatment chamber may be operated at a negative pressure of about 0.5" H20 while the intermediate cham-ber may be kept at a negative pressure of about 0.75" H20.
In the simpLified arrangement illustrated in ~ig L~ a processlng trough 17 is provided in the treatment chamber 13.
This trough, through appropriate controls (not shown, and forming no part of the invention) is supplied wlth liquid ammonia process-ing solution through an infeed line 18. The controls o~ thLs may include a float valve (not shown), for maintaining the processing liquid at an appropriate level in the trough After entering the processing chamber, the ~abric is guided into the trough L7 and thus immersed in the liquid ammonia solution which is at a temperature of about 28F. It is then directed through padding rollers 19, ~or extractian of excess processing solution~ then about a series of adjustable timing rollers 20. After a predetermined reaction time, the fabric is brought into contact with a source of heat9 which flash~s off the liquid ammoniaO In the illustrated system, a pair of Palmer~type dryer units 21, 22 are provided. These include large heated drums 23 about which a confining blanket 24 is trained. For practical purposes, the ammonia react~ons are substantially diminished soon after thc initial contact between the fabric and the first dryer drum. To advantage3 the time interval between initial immersion in the liquid ammonia and initial contact with the first dryer drum is controlled to be within the range of 0 6 seconds to 9 secondsO This can be effectlvely controlled by ~ 9 ~
:~71 3~9 regulation of the length o~ travel between the trough 17 and the first dryer unit ~19 as by adjustment of the rollers 20 to lengthen or shorten the path of the web9 as may be appropriate, However, except as relates to the control of water in the ~abric and in the processing solution and as relates to the controL of the operation of ~he dryer units 21, 229 specific process condi~ions do not fonm a part of this invention.
A~ter leaving ~he second dryer stage 22, the fabric leaves the main treatment chamber 13 through a discharge opening 25, This opening9 like the entrance opening 169 advantageously is provided with a double seal with an intenmediate chamber main~
tained at a slightly more negative pressure than the treatmen~
chamber itseLfO
Fabric leaving the ma~n treatment chamber 139 advantage~
ously may be directed through a steam chamber 269 after which the fabric may be conveyed away to a folder or batcher9 for example.
In ~he processing of fabric in the main treatment chamber 13~ only about 5% of the liquid ~mmonia supplied to the trough 15 is actually consumed~ The remainder is flashed off as ammonia vapor. These vapors are not only potentially hazardous9 but the re-use thereof is economically important in a continuous commercial pro~ess~ Heretofore9 recovery of the ammonia vapors has been carried out by withdrawing vapors from the treatment chamber9 and compressing and condensing the vapors~ Considerable amounts of air are normally contained in the withdrawn gases9 but air is easily separated from the ammonia because of the relative non-condensability of air~ The withdrawn gases also include:quantities - 10 ~ ', ~ ~ 7 ~ ~ O ~
o~ water, which continuaLly enter the process because of the basic moisture content of the fabric and also of the incoming air which, notwithstand;ng the efficiencies of the entrance and exit sealsg is present in certain amounts in the interstices of the fabrlc and en~ers with the fabricO Such amounts of wa~er have9 in the past9 proven difficult to remove as noted ~bove9 necessitating occasional discarding of quantities of the diLuted liquld ammonia9 or its use as a low grade materlal such as in fertilizer appl~
cations~ The process of the present invention is directed to the recovery of the spent ammonia in a manner that enables the water to be easily and effectively removed on a continuous basis a SO
that the process react~ons are not inhibited by excessive water in solution with the otherwise relatively pure anhydrous liquid ammonia, and so that maximum utilization of the liquid ammonia in the processing operation may be real~zed.
In the simplified schematic representatlon of Figo 1~ a surtion line 27 Leads from the main treatment chamber 13 for effecting eontinual withdrawal of gases from the interior of the chamber. These gases are dire¢ted initlaLly to a recovery sec~
tion, generally designated by the numeral 28 in Fig. l, in which the gases are processed to compress and condense the liquid ~mmonia and to separate airO A liquid ammonia storage vessel 29 is pro~
vided for temporary contai~ment of the reco~ered liquid ammonia.
As will be~described in greater detail with respect to Figs~ 2 9 the infeed line 189 through wh~ch the processing trough 17 is supplied, is not dir~ctly connected wi~h ~he storage vessel 299 but rather leads from the recovery section ~8~ The stored liquld ammonia is first directed ~rom the vessel 29 back into the re covery system9 where ~t is utilized in a manner to be described~
and then is directed to ~he processing trough 17 along with an increment of water extracted from the recovered gases~
In accordance w;th conventional practice9 air separated from the recovery system is direct to an incinerator or other disposal facility 300 Likewise ? the mixture of air and steam from the steam chamber 269 containing some residual ammonia gas, is directed through a suction lirle 31 to the disposal ~acllity.
Because of the relatively small amoun~s o ammonia ln these gases, it is considered uneconomical to attempt to recover lto Referring now ~o ~he schematic diagram of Fig. 2a the suction line 27 is shown to lead from the treatment chamber 13 to a non~contact heat exchanger 32 which may be of a shell and tube type. The withdrawn gases, comprising.predominantly amm~nia gas9 but also containing quantities of air and water vapor, may be passed throu~h the shell side of the exchanger9 while cooling medi~m ib-flowed in the tube side of the exchanger~
To advantage9 the non~contact heat exchanger-32 has two heat exchange stages constituting cooling and chilling stages~
In the cooling.stage, water may be u~ilized as the heat exchange medium, being flowed through lines 33~ 34~ In this stage3 gas~s leaving the treatment chamber 13 at a temperature of 9 typically9 about 150F., are pre-cooled in the wa~er section of the exchanger to about:90F7 In the second stage of the heat exchanger9 liquid ammonia desirably is u~ilized as the non-contact heat exchange medi~m. The liquid ammonia is supplied through l mes 33a9 34a9 being supplied at a temperatur~ of around ~8F~ a~d serving to chill the effluent process gases from the .~re~cooled temperature ~78~119 of 90 to9 say9 about ~21F!
Pursuant to one aspect of the mvention9 the low tempera-ture chilling of the effluent gases in the second stage of the heat exchanger 32 serves to condense out of the gas a substantlal fraction of the residual moisture contentO ThLs condensed wa~er fraction can be drained of~ at 32a and collected for ~urther pro-cesslng or low grade utilization~
Because of ~he extremely high affinity of ~mmonia for water, the water fraction condensed in the heat exchanger 32 will inevitably absorb some ammonia, so that the condensate extracted at 32a typically is around a fifty percent mixture of water and ammonia. The overall amounts of collected cond~nsate are gener-ally quite small. Thus, in a typical commer~;al process handling, say, 3000 pounds o~ fabric per kour and thus requiring a process feed of liquid ammonia solution of around 2500 to 3000 pounds per hour3 the outtake of condensate may be on the order of eight to ten gallons per hour, approximately half of which is ammonia~
Insofar as the outtake quantity of ammonia At this stage may be~
come economically significant in a proeess of sufficiently high overall volume, at least somP of the ammonia content of the con- :
densate could be recovered without great diffieulty~
The chilled gases from the heat exchanger 32~ are di~
rected into a desuperhea~ing vessel 36 conta m ing a body 37 of liquid ammonia9 In the process of the invention9 the de~uper~
heating:vessel is maintained at a sl~ghtly negative pressure9 and thus the,-body 37 of liquid ammonla therein is maintained at a temperature on the order o~ ~28F., (or slightly higherg depend~
- 13-~
7~
ing primarily on the total water fraction)~ The incoming process gases can be discharged directly into the lower portion of the de-superheating vessel 36 and bubbled upward through the cold liquid ammonia~ Alternatively, the process gases may be sprayed with liquid ammonia. In either case, the direct contact heat exchange serves to remove superheat from the ammonla gases 9 with the cooled gases acc~mulating in the upper portion 38 of the vessel, along with additional gases which are 1ashed o~f from the liquid itself, in order to maintain its low temperature and liquid phase.
A suction line 39 connect~ the upper portion.of the de superheating vessel 36 with the suction side of a compressor 40 driven by a motor 41~ In the compressor~ the gases comprising principally desuperheated ammonia gas together with alr~ may be compressed to a pressure o~, for exampleg about 180 psigO The compressed gases are heated substantially by the compression and leave the compressor through a high pressure llne 42g at a tempera ture of about 100F O The high pressure l me 42 leads to the shell side of a shell and tube condenser~heat ex~hanger 43~ cooled by water supplied to the tube side by inlet and outlet lines 449 45 Liquid ammonia condensate from the condenser 43~ now at a temperature of about 95F~, is flowed throu~h a high pressure line 46 into the storage and retention vesseL 29u Uncondensed vapors.from the condenseroheat ~xchanger 439 are taken off through a line 47 and directed into a pur~ing vessel 489 in which the un-condensed vapors are fLowed in non-contact heat ex~hange relation-ship with liquid ammonia at Low temperature (typi~ally ~28Fo) and caused to condense~ The condensed material from the purge v~ssel 48, is flowed through a:.llne 49 into the desuperheating ~ ~4 ~
1~78~'3 vessel 36, where the liquid fraction of such mater~al adds to the body of liquid ammonia9 and the contained gaseous fraction, if any, is bubbled through the liquid ammonia and recycled~
Liquid ammonia ~or cooling the purge vessel 48 is drawn from the retention vessel 299 passed throu~h a suitable expanslon valve 50 and directed into the tube side of ~he purge vessel, which typically is a sheLl and tube type heat exchange vessel~
After passing through the tube side o~ the purge vessel 489 the liquid ammonia may be directed through an outlet line Sl and combined with the condensate flowing in the line 499 to the de~
superheating vessel.
In accordance with a significant aspect of the i~ventlon, the liquid ammonia requirements of the process are supplied to th~
main treatment chamber 139 entirely or in subst~ntial part through a l~ne 18 which leads, not directly from the storage vessel 299 but rather from the de~upe~heating vessel 36 whi~h received the efflu~nt in the first place. To this end9 the vessel 36 has an outlet line 52~ leading to the intake side of a suitable pump 53 which dischar~es through a ~ontrol valve means 54 into the line 18a connected to the processing trough 17. To advantage9 the de~
superheating vessel 36 may be provided wi~h appropriate liquid level sensing elements 55, 56, establishing upper and L~wer limits for the level of liquid ammonia thereln. A valve 579 in a liquid ammonia supply line 58 from the high pressure suppLy ve~sel 29, may be controlled by the sensors 559 569 to admit liquid ammonia into the desuperheater vessel, as necessary9 to maintain the de~
sired level thereinO
As will be understood~ ~he fresh9 relatively pure an~
hydrous liquid ~ 15 ~ ~ 7 ~
ammonia admitted into the desuperheating vessel 36 from the storage vessel 29 perfonms several functions. First, the liquid may be directed to the desuperheating vessel 36 while still at a relatively high temperature of around 95F~ for example, and at a relatively high pressure of around 180 psig~ Since the liquid body within the desuperheating vesseL i5 in equilLbrium at a slightly negative pressure and at a temperature o~ around -28F.
a certain amount of the incoming, ~resh liquid ammonia is initi-ally 1ashed of to provide sel~-cooling to the equilibrium con-ditions. In a typical process~ as much as 25% by weight of the liquid ammonia rom the storage vessel is flashed off as gas in order to effect self-cooling to -28F~ of the remaining 75%O
Significant advantages are realized, in the process of the invention, by effecting self~cooling of the re~liquefied ammonia at the desuperheater stage~ rather than in the treatment chamber 13, as would be the case if the re~liquefied ammonia were taken directly from the storage vessel 29 to ~he treatment chamber.
As will be appreciated, large volumes of ammonia are required for the self-coollng action and, where sueh volum~s are released with~
in the treatment chamber 13, as in the past, this serves to in~
crease the energy requiremen~s of the heating section of the pro-cessing chamber and correspondingly to increase the cooling re-quirements of the ammonia recovery system~
In the operation of the system of Fig. 29 liquid ammonia, rontaining a mlnor fraction of water, is directed through the lines 52, 18 into the processing chamber 13, and is supplied direc~ly to the trough 17. The fabric web 10 is continuously advanced in~o and through the processing chamber at a predetanmined ~ 16 -1~7~3~L09 speed. As the fabric en~ers the chamber, it is immersed in ~he trough 17 and becomes saturated with the liquid ammonia solution.
When the processing equipment is in a steady-state condition, the chamber 13 is fully saturated with ammonia vapors so that, when the fabric emerges from the trough 17 and travels to the point o its initial contact wlth the dryer unit 21~ lt remains e~fectively saturated with the liquid ammonia. During thl~ ln~erval, the principal desired reactLons between the ammonla and the ~abric occur Soon after the ~abric is flashed o~f to substantialLy tenminate the reaction, and the balance is substantially removed as the fabric travels over the dryer units 21, 22.
Although the relationship of fabric processed to ammonia solution utilized may vary widely with different fabrics, a reW
lationship of one pound liquid ~mmonia infeed to one;pound of fabric infeed is not untypical and will be assumed for the pur-poses of illustration herein. Thusg for each pound of fabric e~tering the chamber, a pound of the liquid ammonia solu~ion is ~bsorbed ~rom the trough 17 and carried away with the moving fabric, wi~h approximately 95% of tha~ ~mount being 1ashed by the dryer units 21, 22. Thus, for each pound of fabric processed, nearly a pound of spent gases must be withdrawn from the chamber 13.
Because the incoming fabric conveys trappe~ air within its interstices, and because that air inherently will contain som moisture, the atmQsphere within the chamber 13 necessarily will become partly dilu~ed wi~h air and its mois~ureO This will occur regar~less of the ef~ica~y of the seals at the entrance and exit openings. When this ammonia~rich mixture of gases is withdra~ from the chamber and bubbled through the desuperheating vessel 36, the moisture fraction in the gases readily condenses in the body 37 of liquid ammonia, which is at approximately -28F.
In addition, for some processing operations, an additional mois-ture fraction may be driven off of the fabric by the heat of the dryers 21,22. Unless properly dealt with, these water fractions will accumulate in the vessel 36, causing the temperature in the bath 37 eo progressively rise until it is no longer serving its intended function, and must be e~tracted and discarded an/or used in low grade application. In accordance with the invention, however, the water-containing liquid ammonia in the desuperheating vessel 36, is constantly extracted through the line 52 and uti~
lized as the make-up feed to the impregnating trough 17.
As an integral part of the process of the invention, pro-vision is made for the constant removal of water from the process, on a convenient and economical basis. Although the particular technique utilized for water extraction is not critical to the basic process of the invention) it is of~rourse critical that some means be provided for water removal. To greatest advantage, and as one of the specific aspects of the in~ention, water is most convenient-ly removed by a combination of techniques, including mechanically conveying a water fraction out with the processed fabrics, where practicable and condensing a water fraction out of the hot ef-fluent gases extracted from the treatment chamber~ Thus, where processing conditions permit, it is advantageous to so control the time-temperature relationships of the heating section as to drive off primarily the ammonia fraction while substantially re-training the wa~er fraction in the fabric. By this means, the -fabric can be caused to leave the process with a slightly gxeater ~' :.
7 ~ ~ g moisture content than when it enters, resulting in a net out~ake of water from the processing system.
Since not all fabrics and not all proc~ssing conditions admit of optimum control of the heating sec~ions, secondary pro-vision is made for pre-cooling and then chiLli~g ~he hot ef~luent gases from the process, in order to condense out at least part of the water fraction in the spent gasesO By pre-chilling the spent gases down to about -21F., for example, which ls readily accomplished in a non-contact heat exchanger of practical propor-tiQns, using available liquid ammonia as the chilling agent, the water fraction may easily be reduced down to 2~3%. By thus pro-viding for alternative water removal by fabric conveyance or by condensation from the hot effluent gas, optimum process efficien-cies may be realized. Where the nature of the fabric-and the particular procesaing admits, the heating stage may be oo~trolled to ach~eve a net outflow of water on the fabric itself. H~wever, where the process cannot be operated in this ideal manner, the resulting high moisture content of ~he hot effLuent gases will be significantLy reduced by chilling in the non-contact heat ex-changer 32 The system of the invention is uniquely effe tive in eliminating the build-up of undesired quantities of water in the systPm and~ at the same t~me, ~ignificantly improving the thenmo-dynamic efficien~y of the system, by drawing upon the ~ody o~
water-containing liquid ammonia solut~on in the desuperheating vessel for ~he supply o~ process solution. By feeding this solu-tion back ~nto the process, the water fraction, which is inherent-ly going to be present in ~he recovexed process gases, ls - 19 ~
~ ~ ~ 8~ ~ 9 prevented from accumulating to an undesired level and can be re-moved at a convenien~ stage of the process.
Under ideal condi~ions of process operation, the steady-state residual water content in the desuperhea~er vessel may be maintained at ex~remely low level. Even under adverse conditions, the water content of the desuperheating vessel may be easily kept at levels (2-3% or less) which enabLes both the primary treating process itself, and also the recovery sys~em, ~o be operated at highly efficient levels.
One of ~he signiflcant dditional advantages of the uni-que process is the improved thenmodynamic efficiency which results from feeding the re-liquefied ammonia into the desuperheating ves-sel, rather than directly into the process chamber 13~ Thus, the re-liquefied ammonia in the starage vessel 29 is both at high pressure and at a relatlvely elevated temperatureO At the time of use, the liquid ammonia must be brought to equilibrium at sub-stantially atmospheric pressure (actually slLghtly below atmos-pheric) and at an equilibrium temperature of about -28F~ In order to achieve this equilibrium ~tate, substantial percentages of the re-liquefied ammonia are flashed off as gas9 When this is caused to occur at the desuperheating vessel~ these substantial quantities o~ flash~d-o~f gases are simply recycled throu~l the recovery s~stem, compressed and re-liquefied~ I~, on the other hand~ the gases are flashed off in the treatment chamber 13, as according to prior practice, the flashed-off gases are returned to the recovery system only after being exposed to substantial heat within the treatment chamber~ As will be appre~iated, the heat which goPs mto elevating the temperature of that fraction - 20 ~-~ ~ 8 1 ~ ~
of gas which is flashed off merely to bring the liquid ~mmonia to an equilibrium condition represents a waste of heat energy in the he~ting section of the processu Likewise, in order to re~
quefy and recover this gas~ the heat ~ust be removed therefrom, which serves to increase the working lo~d on the compressor~ Thus, in the new process, by deriving the process ~eed ~rom ~he desuper-heating vessel, and ~tilizlng the re-lique~ied ammonia as make~up feed to the vessel and not directly to the process chamber, not only is the water conten~ o the system stabilized at an appropri-ate equilibrium level, bu~ significant energy efficiencies are realized.
The system of the invent10n is uniqueLy effective in eliminating undesired water from the recir~ulating ammonia system~
This is of criti~al importance~ ~n a practical, commercial system9 because there is almost a twenty~to~one ratio between the amounts of æmmonia recycled and the ~amount basically consumed ~n the pro-cess, such that effective reclaiming te~hniq~es are vitalq Here-tofore, such reclaiming techniques have been severely limited by the practical difficulties ln ridding:the~system of water which unavoidably en~ers the system.
The process and system of the present invention, operate on the ba~is of condensing out the water frac~ion a~.an early stage in the recovery processJ by dire~t GOntaCt with a body cf cold liquid ammonia,.with or-without a prior non contact conden~
sation stage, to provide the make~up supply to ~he processl The condensed water in the desuperheating vessel is thus fed dirçctly back into the process as qui~kly as it enters~.enabling a steady stae ~evel to be rea hed which~ experience ha$ shown7 is ~7~1~g suficiently low as to ha~e insignificant effects upon the process reactions. Thus, while as much as LO% moisture in th~ liquid ammonia solution may substantially inhibit the desired reactions, the water fraction introduced into the processing solutio~ by the system of the invention, represents a rela~ively insignificant increment. In any case, prov~slon may be made ~or predrying the incoming fabric, not only ~o minimize incoming moisture content, but aLso, under some conditions, enabling a water fraction to be removed by the fabric. Thus, in An ldeal process 9 fabrlc may enter the process with a mois~ure content on the order of 5%, be subjected to the desired liquid ~mmonia reactions, and leave the process with a moisture content on the order, for example, 5.1%~
By this means, the fabric itself serves as a continuous means of extracting water from the ammon~a reco~ry system, permitting the system to operate on an ex~remely efficient basis~ with a minimum wastage or low grad~ utilization of the recovered material. Where such ideal conditions are not realizeable, other means, s~ch as non-contact condensation of spent gases~are utilized to extract a water fraction.
It should be understood, of course, that the form of the invention herein illustrated and described is ~nte~ded to be representative only, as certain changes may be made therein with-out departing~from the clear teachings of the disclosure. Ac-cordingly, reference should be made to the following appended claims in detenmining the full srope of the invention.
~- 22 r
Claims (13)
1. In a continuous process for recycling gaseous effluents, comprised principally of gaseous ammonia, air, and water vapor, derived from the continuous treatment, with substan-tially anhydrous liquid ammonia, of a moving cellulosic-containing web of material, and wherein the moving web is continuously exposed in a confined treatment zone to said liquid ammonia at near-atmospheric pressure, and said web is thereafter heated in said zone to vaporize and remove said liquid ammonia from said web, the improvement characterized by (a) continuously withdrawing said gaseous effluent from said zone, (b) continuously removing a portion but less than all of the water vapor fraction from said gaseous treating zone effluent, (c) continuously introducing said withdrawn gaseous-effluent into a body of substantially anhydrous liquid ammonia maintained at about atmospheric pressure to cool said gaseous ammonia and to condense water vapor from said gaseous ammonia, (d) thereafter compressing and condensing the gaseous ammonia, (e) continuously withdrawing substantially anhydrous liquid ammonia, together with condensed water, from said body and supplying the withdrawn liquid to said treatment zone for said exposing step, and (f) continuously replenishing said body of substantially anhydrous liquid ammonia with anhydrous liquid ammonia from said compressing and condensing step.
2. The process of claim 1, further characterized by (a) said water vapor removing step being carried out by continuously condensing out a portion of said process effluent prior to the step of introducing said effluent into said body of substantially anhydrous ammonia.
3. The process of claim 1, further characterized by (a) a portion of the water contained in the substantially anhydrous liquid ammonia furnished to said treatment zone being carried out of the zone by said web.
4. The process of claim 3, further characterized by (a) the additional step of pre-drying said web prior to its entry into said treatment zone.
5. The process of claim 2, further characterized by (a) said water removal step being carried out by non-contact heat exchange with liquid ammonia.
6. The process of claim 5, further characterized by (a) the additional step of cooling said effluent by non-contact heat exchange with water prior to said condensing step.
7. In a continuous process for recycling the effluent, comprised principally of gaseous ammonia, air, and water vapor derived from continuously treating a moving web of material with substantially anhydrous liquid ammonia in a treatment zone, wherein the treatment comprises continuously exposing said web in said zone to said substantially anhydrous liquid ammonia, immedi-ately thereafter, heating said web in said zone to vaporize and remove said liquid ammonia from said web, the improvement charac-terized by (a) continuously withdrawing said effluent from said zone, (b) continuously pre-condensing out a portion of said effluent by non-contact heat exchange with liquid ammonia, (c) the pre-condensing step continuously removing a portion of condensed water vapor and ammonia from said process, (d) continuously introducing the remainder of said effluent not removed from said pre-condensing step into a first body of chilled substantially anhydrous liquid ammonia maintained at atmospheric pressure, to chill said gaseous ammonia and condense remaining water vapor, (e) the heat from said introducing step generating an additional ammonia gas fraction, (f) compressing and condensing the ammonia gas, including said fraction, to provide a retained second body of liquid ammonia at super-atmospheric pressure, (g) continuously withdrawing substantially anhydrous liquid ammonia together with condensed water from said first body and supplying the withdrawn liquid to said treatment zone for said exposing step, and (h) continuously replenishing said first body of substantially anhydrous liquid ammonia from said retained second body.
8. The process of claim 7, further characterized by (a) the additional step of continuously removing water from said treatment zone by said continuously moving web.
9. The process of claim 8, further characterized by (a) the additional step of continuously pre-drying said continuously moving web prior to entry into such treatment zone.
10. The process of claim 7, further characterized by (a) the water content of said first body being continuously maintained at a level of between about 2 and 3% or less.
11. The process of claim 7, further characterized by (a) said pre-condensing step cooling the remainder of said effluent to about -21°F.
prior to introduction into said first body.
prior to introduction into said first body.
12. In a continuous process for recycling the effluent, comprised principally of gaseous ammonia, air, and water vapor derived from continuously treating a moving web of material with substantially anhydrous liquid ammonia in a treatment zone, wherein the treatment comprises continuously exposing said web in said zone to said substantially anhydrous liquid ammonia, immedi-ately thereafter, heating said web in said zone to vaporize and remove said liquid ammonia from said web, the improvement charac-terized by (a) continuously withdrawing said effluent from said zone, (b) continuously introducing said effluent into a first body of chilled substantially anhydrous liquid ammonia maintained at atmospheric pressure, to chill said gaseous ammonia and condense retained water vapor, (c) the heat from said introducing step generating an additional ammonia gas fraction, (d) compressing and condensing the ammonia gas, including the above mentioned gaseous fraction and the further gaseous fraction referred to in subparagraph (g) hereof, to provide a retained second body of liquid ammonia at super-atmospheric pressure and at a temperature above the equilibrium temperature of liquid ammonia at near-atmospheric pressure, (e) continuously withdrawing substantially anhydrous liquid ammonia together with a condensed water fraction from said first body and supplying the withdrawn liquid to said treatment zone for said exposing step, and (f) continuously replenishing said first body of substantially anhydrous liquid ammonia from said retained second body, (g) said replenishing step generating a further gaseous ammonia fraction while cooling the newly added liquid ammonia to the equilibrium temperature of said first body.
13. The process of claim 12, further characterized by (a) the additional step of continuously removing water from said treatment zone by said continuously moving web.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/679,059 US4074969A (en) | 1974-07-19 | 1976-04-21 | Process for recovery and reuse of ammonia in a liquid ammonia fabric treating system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1078109A true CA1078109A (en) | 1980-05-27 |
Family
ID=24725417
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA263,240A Expired CA1078109A (en) | 1976-04-21 | 1976-10-13 | Process and apparatus for recovery and reuse of ammonia in a liquid ammonia fabric treating system |
Country Status (16)
| Country | Link |
|---|---|
| JP (1) | JPS5853108B2 (en) |
| AR (1) | AR211942A1 (en) |
| BE (1) | BE850054A (en) |
| BR (1) | BR7607794A (en) |
| CA (1) | CA1078109A (en) |
| CH (1) | CH613580GA3 (en) |
| DD (1) | DD130667A5 (en) |
| DE (1) | DE2656719A1 (en) |
| FR (1) | FR2348727A1 (en) |
| GB (1) | GB1525879A (en) |
| HK (1) | HK51479A (en) |
| MX (1) | MX145463A (en) |
| NL (1) | NL7613341A (en) |
| OA (1) | OA05642A (en) |
| TR (1) | TR19638A (en) |
| ZA (1) | ZA772385B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS585999Y2 (en) * | 1978-05-19 | 1983-02-01 | 株式会社東芝 | nuclear fuel elements |
| CN102296435B (en) * | 2011-05-16 | 2013-05-15 | 东华大学 | Feeding and unloading automation device and method for liquid ammonia modification of fiber and yarn |
| JP2015000842A (en) * | 2013-06-18 | 2015-01-05 | 日本パイオニクス株式会社 | Recovery method of ammonia and reuse method of ammonia using the same |
| EP3152358B1 (en) * | 2014-06-06 | 2018-04-11 | REGGIANI MACCHINE S.p.A. | Method for dyeing and finishing textile material and corresponding apparatus |
| CN112879799B (en) * | 2021-03-10 | 2022-09-23 | 大唐贵州发耳发电有限公司 | Ammonia gas replacement method for overhauling liquid ammonia tank |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1433022A (en) * | 1964-04-25 | 1966-03-25 | Sentralinst For Ind Forskning | Process for treating fabrics containing cellulosic fibers with liquid ammonia |
| IE34124B1 (en) * | 1969-05-08 | 1975-02-05 | Tedeco Textile Dev Co As | Apparatus for treatment of fabrics with liquid ammonia |
| US3721097A (en) * | 1970-11-16 | 1973-03-20 | Cluett Peabody & Co Inc | Ammonia effluent recovery and liquefaction from textile treating zone |
| AU465072B2 (en) * | 1971-01-14 | 1975-09-18 | Cluett, Peabody & Co., Inc | Method and apparatus for quickly treating fabrics with liquid ammonia |
-
1976
- 1976-10-13 CA CA263,240A patent/CA1078109A/en not_active Expired
- 1976-11-22 BR BR7607794A patent/BR7607794A/en unknown
- 1976-11-22 GB GB48598/76A patent/GB1525879A/en not_active Expired
- 1976-11-26 AR AR265629A patent/AR211942A1/en active
- 1976-11-30 MX MX167229A patent/MX145463A/en unknown
- 1976-11-30 NL NL7613341A patent/NL7613341A/en not_active Application Discontinuation
- 1976-12-01 CH CH1513376A patent/CH613580GA3/en unknown
- 1976-12-13 FR FR7637528A patent/FR2348727A1/en active Granted
- 1976-12-15 DE DE19762656719 patent/DE2656719A1/en not_active Withdrawn
- 1976-12-20 TR TR19638A patent/TR19638A/en unknown
- 1976-12-23 JP JP51156125A patent/JPS5853108B2/en not_active Expired
- 1976-12-31 BE BE173808A patent/BE850054A/en unknown
-
1977
- 1977-04-19 DD DD7700198476A patent/DD130667A5/en unknown
- 1977-04-20 OA OA56148A patent/OA05642A/en unknown
- 1977-04-20 ZA ZA00772385A patent/ZA772385B/en unknown
-
1979
- 1979-07-26 HK HK514/79A patent/HK51479A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| OA05642A (en) | 1981-04-30 |
| DD130667A5 (en) | 1978-04-19 |
| FR2348727B1 (en) | 1980-12-19 |
| AR211942A1 (en) | 1978-04-14 |
| TR19638A (en) | 1979-09-04 |
| MX145463A (en) | 1982-02-19 |
| DE2656719A1 (en) | 1977-11-03 |
| NL7613341A (en) | 1977-10-25 |
| JPS5853108B2 (en) | 1983-11-26 |
| ZA772385B (en) | 1978-03-29 |
| FR2348727A1 (en) | 1977-11-18 |
| JPS52128494A (en) | 1977-10-27 |
| BR7607794A (en) | 1977-10-11 |
| BE850054A (en) | 1977-04-15 |
| HK51479A (en) | 1979-08-03 |
| GB1525879A (en) | 1978-09-20 |
| CH613580GA3 (en) | 1979-10-15 |
| CH613580B (en) |
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