EP0741599A1 - Procede optimise de retraitement de courants de buees a base de vapeur d'eau - Google Patents

Procede optimise de retraitement de courants de buees a base de vapeur d'eau

Info

Publication number
EP0741599A1
EP0741599A1 EP95906986A EP95906986A EP0741599A1 EP 0741599 A1 EP0741599 A1 EP 0741599A1 EP 95906986 A EP95906986 A EP 95906986A EP 95906986 A EP95906986 A EP 95906986A EP 0741599 A1 EP0741599 A1 EP 0741599A1
Authority
EP
European Patent Office
Prior art keywords
vapor
stream
liquid
separation
condensate
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.)
Withdrawn
Application number
EP95906986A
Other languages
German (de)
English (en)
Inventor
Wilfried Rähse
Reiner Vogler
Johann Friedrich Fues
Wilhelm Beck
Kathleen Paatz
Truc Tran Anh
Yüksel LEVENT
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Henkel AG and Co KGaA
Original Assignee
Henkel AG and Co KGaA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Henkel AG and Co KGaA filed Critical Henkel AG and Co KGaA
Publication of EP0741599A1 publication Critical patent/EP0741599A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D5/00—Condensation of vapours; Recovering volatile solvents by condensation
    • B01D5/0027—Condensation of vapours; Recovering volatile solvents by condensation by direct contact between vapours or gases and the cooling medium
    • B01D5/003—Condensation of vapours; Recovering volatile solvents by condensation by direct contact between vapours or gases and the cooling medium within column(s)
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
    • B01D17/02—Separation of non-miscible liquids
    • B01D17/0208—Separation of non-miscible liquids by sedimentation
    • B01D17/0214—Separation of non-miscible liquids by sedimentation with removal of one of the phases
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
    • B01D17/02—Separation of non-miscible liquids
    • B01D17/04—Breaking emulsions
    • B01D17/042—Breaking emulsions by changing the temperature
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
    • B01D17/02—Separation of non-miscible liquids
    • B01D17/04—Breaking emulsions
    • B01D17/045—Breaking emulsions with coalescers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
    • B01D17/08—Thickening liquid suspensions by filtration
    • B01D17/085—Thickening liquid suspensions by filtration with membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D5/00—Condensation of vapours; Recovering volatile solvents by condensation
    • B01D5/0057—Condensation of vapours; Recovering volatile solvents by condensation in combination with other processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D5/00—Condensation of vapours; Recovering volatile solvents by condensation
    • B01D5/0078—Condensation of vapours; Recovering volatile solvents by condensation characterised by auxiliary systems or arrangements
    • B01D5/0093—Removing and treatment of non condensable gases
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/029—Multistep processes comprising different kinds of membrane processes selected from reverse osmosis, hyperfiltration or nanofiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/147—Microfiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/16—Feed pretreatment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
    • C07B63/00—Purification; Separation; Stabilisation; Use of additives
    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
    • C11B9/00—Essential oils; Perfumes
    • C11B9/02—Recovery or refining of essential oils from raw materials
    • C11B9/022—Refining
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B25/00—Details of general application not covered by group F26B21/00 or F26B23/00
    • F26B25/005—Treatment of dryer exhaust gases
    • F26B25/006—Separating volatiles, e.g. recovering solvents from dryer exhaust gases
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
    • B01D17/02—Separation of non-miscible liquids
    • B01D17/04—Breaking emulsions
    • B01D17/047—Breaking emulsions with separation aids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
    • B01D17/02—Separation of non-miscible liquids
    • B01D17/04—Breaking emulsions
    • B01D17/048—Breaking emulsions by changing the state of aggregation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working

Definitions

  • the teaching of the invention is based on the object of demonstrating improvements for the separation of water vapor-based vapor streams which occur at least in part in a mixture with components of organic origin in the context of a wide variety of process technologies.
  • the problem given here can be briefly represented as follows:
  • reaction products Another typical field of work for the use of cleaning by steaming with industrial importance is the removal of residues based on ethylene oxide and / or propylene oxide from reaction products, which by ethoxylation and / or propoxylation of organic compounds with at least one active Hydrogen atom have been produced.
  • Compounds of this type are important as nonionic surfactants or as intermediates for the preparation of anionic surfactant compounds. They are used, for example, in the field of wetting agents, detergents and cleaning agents, but to a large extent also in the field of cosmetics or pharmaceutical auxiliaries.
  • the reaction products primarily obtained contain traces of ethylene oxide and / or propylene oxide and of undesired reaction secondary products such as dioxane due to the production process.
  • Superheated steam-based vapor streams containing valuable substances and / or pollutants that are volatile in steam are produced to a great extent in the course of drying aqueous valuable substances and mixtures of valuable materials, in particular when drying corresponding aqueous preparations, with steam as the drying gas, which has been overheated under process conditions. Drying processes of this type have become increasingly important in the recent past.
  • the material to be dried can be processed in fluidized beds and / or fluidized beds.
  • the use of superheated steam has also been proposed for spray drying aqueous preparations.
  • the problem according to the invention also arises in other related fields, for example the extraction or recovery of water-vapor-efficient parts from feedstocks which can be assigned to the following fields: nutrients, in particular foodstuffs (food and beverages) and foodstuffs starting materials for their production, preparations containing aroma substances (odorants and flavors), preparations from the fields of cosmetic and pharmaceutical auxiliaries and / or valuable substances and the like.
  • feedstocks which can be assigned to the following fields: nutrients, in particular foodstuffs (food and beverages) and foodstuffs starting materials for their production, preparations containing aroma substances (odorants and flavors), preparations from the fields of cosmetic and pharmaceutical auxiliaries and / or valuable substances and the like.
  • the processing of such feedstocks using superheated steam as a working aid - be it for drying corresponding aqueous preparations or for the targeted extraction of water vapor-volatile materials or valuable materials - is the subject of the earlier German patent application DE 4326468.
  • the teaching of the invention described below is based in particular on the task, the two main problem areas when working up and to dispose of water vapor streams containing at least partially organic materials in a combined process in a technically improved form.
  • These two main problem areas are the simplified separation of the vapor condensate into, on the one hand, at least largely pure water and, on the other hand - separately from this - the steam-volatile component (s) and the possibility of optimized energy recovery from the condensation of the water vapor-based vapor ⁇ current, which has been subtracted as a product stream from the previously affected work stage.
  • the invention relates in a first embodiment to the method for optimized processing of a superheated steam stream loaded with water vapor-volatile organic components - hereinafter also referred to as "vapor stream" - which can also be present as superheated superheated steam under process conditions Condensation of the vapor phase with recovery of the heat of condensation and at least partial separation of the volatile organic components from the aqueous condensate.
  • vapor stream water vapor-volatile organic components
  • the process according to the invention is characterized in that the thermal energy to be removed from the continuously supplied vapor stream for its condensation is at least predominantly transferred in direct contact to a circulated and cooled liquid stream of condensed vapors, the amount of energy taken up from this cycle stream transferred to a second carrier by indirect heat transfer, taking a partial flow from the circuit of the condensed vapors and subjecting it to material separation in a membrane separation process.
  • the teaching according to the invention encompasses the use of this process principle for the condensation and emulsion splitting of vapor streams from the hot gas drying of valuable materials and / or mixed materials from the area of wetting agents, detergents and / or cleaning agents, in particular with superheated steam as hot gas in the frame spray drying or fluidized bed drying.
  • the subject of the invention is the application of the previously described method for working up superheated steam streams from the distillative separation of multi-component mixtures, at least partly of organic origin, by steaming.
  • FIG. 1 Further embodiments of the invention relate to the use of this process principle for the recovery of valuable substances, in particular aroma and / or fragrance substances, during their extraction and / or purification from a feed material that is preferably liquid and / or solid under normal conditions of pressure and temperature.
  • the invention relates to the use of this process principle for the separation of pollutants from and for the disposal of appropriately contaminated steam-based vapor streams.
  • the vapor stream to be worked up and loaded with organic components is brought into direct contact and exchange with a selected liquid stream for its condensation with absorption and dissipation of the thermal energy thereby released.
  • a liquid stream that is cooled in a targeted manner is condensed and circulated. of leading brothers.
  • This vapor circuit flow, now loaded with the absorbed energy - but kept in the liquid phase - is brought into indirect heat exchange with a second carrier. The amount of energy absorbed is transferred to the second carrier by means of indirect heat transfer.
  • a partial stream is withdrawn from the circuit of the condensed vapors and subjected to material separation in a 1-stage or multi-stage membrane separation process.
  • Maintaining the correct temperature of the circulation flow of the vapor condensate used as a direct coolant can be of crucial importance for a trouble-free implementation of the continuous process. This is understandable, for example, for the application of drying valuable materials from the area of wetting agents, detergents and / or cleaning agents with superheated steam.
  • the vapor part stream drawn off from this drying stage which is the "vapor stream" to be treated in the sense of the definition of the work-up process now concerned, will generally be loaded with a plurality of components of the dried-up material mixture which are volatile in steam, which are generally there as contaminating accompanying substances are present.
  • anionic surfactants based on fatty alcohol sulfates contain residual portions of unreacted fatty alcohols that are produced during drying are discharged with superheated steam as volatile components. For the process according to the invention, they are thus volatile organic components which are to be separated from the condensed aqueous phase.
  • fatty alcohols of the type concerned here can have melting points, for example in the range from 50 ° C. or even above.
  • the circulation flow of the vapor condensate used as the direct coolant and in particular the partial flow withdrawn into the membrane separation is kept at a temperature level which excludes a blockage of the liquid circuit and in particular the membrane separation by condensed organic components.
  • the lower temperature limit of the vapors flow in the circuit or at least the partial flow drawn off for the membrane separation at about 60 or 70 ° C in order to rule out the formation of fine-particle and possibly plastic solid phases in these liquid flows.
  • This limitation does not imply any real restriction on the feasibility of the method according to the invention.
  • the second freedom consists in the quantity of this cooling liquid phase supplied.
  • the required energy absorption capacity in the first direct cooling stage can nevertheless be made available by increasing the circulation speed of this liquid phase even when large quantities of vaporous vapor flow are produced .
  • the combined condensate flow resulting from the direct energy exchange with the liquid stream circulating generally contains a considerable proportion of organic compounds in the state of very fine emulsification. In the periods available for the continuous process, these emulsions give no, or at best only slight, segregation into separate phases. It is also possible, however, that portions of the organic components introduced into the vapor stream tend to demulsify sufficiently quickly that an organic phase which is generally floating and which is formed by an aqueous-organic one is formed, for example in an intermediate residence container Emulsion phase is sub-layered.
  • demulsified portions of the vaporizable organic components are removed from the liquid vapor condensate by phase separation and exclusively or at least essentially feeds the portion of the liquid condensate phase to the process circuit which contains the aqueous-organic dissolved and / or stably emulsified organic portions.
  • it may be essential, in particular for the nature of the partial liquid flow to be fed into the membrane separation stage, to use only or at least predominantly corresponding liquid phases.
  • An important aid for the problem-free implementation and adaptation of the processing method according to the invention lies in the possibility of carrying out the method in its entirety or at least the individual method steps separately in the range of normal pressure.
  • the direct condensation in the first stage of the process can be carried out industrially by transferring the thermal energy of the supplied vapor stream to the circulated vapor condensate stream in any manner known per se. It is particularly simple here to design this process stage as condensation of the vapor part flow in a countercurrent washing device in which the vaporous and the liquid phase with a large surface area are guided in countercurrent to one another.
  • This process step can be particularly simple be carried out in washing columns which are equipped in particular with packing or similar elements, such as bubble trays and the like, the cooled vapor condensate stream advantageously being fed in at the top, while the vaporous vapor stream to be condensed is introduced from below in countercurrent.
  • the condensation of the vapor part current can be carried out in one stage, but also in several stages.
  • the energy portion of the vapor drawn off in such a condensation stage is kept as low as possible in order to ensure the inventive concept of the greatest possible energy return in the described second energy exchange step.
  • By appropriately guiding the second liquid flow it is also possible in such special cases to recover the total energy supplied via the vapor flow.
  • indirect energy exchange is already being carried out, and thus this portion of the condensation energy is also accessible for recycling.
  • such a partial precondensation of the vapor stream to be purified is restricted in such a way that more than 50%, in particular more than 75% and expediently more than 85% of the total condensation energy obtained in the stage of direct exchange enter between vapor and the liquid vapor condensate.
  • the liquid stream leaving the first process stage of direct cooling is fed - optionally after the separation of an organic closed phase which is formed - as an aqueous solution or emulsion of organic components carried with it to the second energy transfer stage, which is designed as indirect cooling.
  • the branching of the partial flow to be discharged into the membrane separation plant can take place before and / or preferably after this indirect cooling stage.
  • the condensate liquid flow is returned to the primary washing stage.
  • the aqueous organic phase can be worked up effectively, taking into account today's one-day technology and with high space / time yields.
  • the selection and adaptation of the respective membrane Separation processes according to the type and nature of the selected membranes and the particular technology to be used are determined by the mixture of substances to be separated.
  • the loaded aqueous phase can be worked up in one or more stages.
  • the selection of the appropriate membrane types ranges from microfiltration to the area of ultra and nanofiltration to reverse osmosis.
  • the technical action is determined in detail by the circumstances of the mixture of substances to be separated which are to be taken into account in each case.
  • a multi-stage condensate purification is used in the membrane separation stage, then it can be particularly expedient to provide semi-permeable membranes with a gradually increasing separation effect in the successive separation stages.
  • a microfiltration of the first stage can be combined with a subsequent ultrafiltration or a subsequent nanofiltration.
  • the second separation stage it is also possible to work in the sense of a reverse osmosis.
  • combinations in the sense of ultrafiltration / nanofiltration or ultrafiltration / reverse osmosis are also possible.
  • separating membranes used are based on the individual circumstances. Numerous semipermeable membrane types of organic origin are known which can be used in the process according to the invention. However, it is generally preferred to use ceramic membrane types which are customary today for this separation stage in the process according to the invention.
  • Inorganic membrane systems currently on the market consist, for example, of a tubular support material, for example based on carbon, with a sintered-on membrane layer made of metal oxides, for example zirconium dioxide.
  • the membranes are combined into modules in tubular form. The design of the modules is designed for high chemical and mechanical resilience. Ceramic membranes of this type have important advantages. In particular, they are not only temperature-resistant, but also have a high resistance to chemicals, for example to solvents and oxidizing agents.
  • the membranes cannot be attacked by microorganisms.
  • Inorganic membranes of the type described usually have high filtrate flow flows and, accordingly, bring high performance even with increased viscosities. They enable the use of increased operating pressures, for example up to 10 bar, and the use of high flow velocities.
  • the membrane life is up to several years. The signs of aging of the membranes are slight. Differences in pressure and pressure surges have practically no influence on the membrane structure.
  • FIGS. 1 to 3 show specific configurations of the working principle according to the invention. The following applies in particular:
  • the process diagram in FIG. 1 shows the principles of acting according to the invention in the sense of a 1-stage process both in the condensation and energy exchange stage and in the downstream stage of the membrane separation process.
  • the vaporous vapor stream to be cleaned - for example a vapor waste stream resulting from the drying with superheated steam, which is loaded with volatile organic components from the material to be dried - is fed via line 1 to the washing column 2 in the lower part, with packings 3 inside this washing column the exchange between vapor and liquid phase with an enlarged surface is ensured.
  • the liquid vapor condensate flowing downward in the washing column collects in the lower part of this washing column 2 and separates here into the stable aqueous-emulsified liquid phase portion 4 and a floating oil / fat phase 5.
  • This portion of the organic load to be separated from the vapor stream can be drawn off via line 6 by means of simple phase separation.
  • the stable aqueous emulsion 4 is withdrawn by means of the pump 7 at the bottom of the washing column via line 8 and fed via line 9 to the indirectly working heat exchanger 10 for heat recovery.
  • the aqueous emulsion cooled in a certain manner is returned to the top of the washing column 2 via lines 11 and 12 and is applied here, for example, via spray nozzles 13 to the packing or packages 3 above.
  • the stream of the second and indirectly used cooling medium is fed via 14 to the indirect heat exchanger 10 and withdrawn therefrom via 15.
  • a partial flow is withdrawn from the circulation flow of the vapor condensate by means of the pump 16 via line 17 and fed to the membrane separation system 21 with the semi-permeable membrane 22 via lines 18 and 20 by means of pump 19.
  • the aqueous permeate stream can be drawn off from the membrane separation stage via 23 and, after a final heat exchange in 24, can be passed, for example, into the waste water.
  • the retentate retained in the membrane stage is removed via line 25. It can be partly recycled to the membrane separation stage via 26 and pump 19, for the rest - or even completely without such a partial recirculation - it is removed via line 27 and, for example, sent for recycling.
  • Vapor flows of the type concerned here generally contain minor proportions of non-condensable gases, in particular a correspondingly low proportion of inert gas.
  • this gaseous fraction is drawn off at the top via 28, subjected to a post-condensation in the cooler 29 and separated into the liquid fraction to be returned via line 30 and the inert gas fraction which, if appropriate after passing through an additional heating stage 31, over the line 32 is withdrawn. If organic components are still contained in this exhaust gas component, these can be reliably eliminated by supplying the gas stream withdrawn via 32, for example, to a combustion stage.
  • FIG. 1 The method principle shown in FIG. 1 is described in FIG. 2 in a technologically refined embodiment.
  • the working principles according to the invention are also implemented here, but both the stage of the condensation of the vapor stream and the downstream membrane separation are now designed in several stages. The following applies in particular:
  • the vapor stream to be worked up is fed by means of the blower 33 via line 34 to a storage container 35 in which a large amount of liquid vapor condensate 36 is present in the liquid phase.
  • a separate, at least predominantly organic phase is deposited on the surface of the hot aqueous-organic emulsate phase and can be removed via 37.
  • the hot vapor stream is introduced via line 34 directly into the hot aqueous emulsate phase 36 and a substantial proportion of it is condensed.
  • Liquid condensate is drawn off at the bottom of the storage container 35 via 39 centers of the pump 38 and fed via line 40 to the subsequent indirect heat exchanger 41, which is in principle comparable to the indirect heat exchanger 10 from FIG. 1.
  • the circulating liquid vapor condensate stream leaves the indirectly working heat exchanger in a predetermined manner, cooled via line 42, and is partly returned to the head of the day container 35 and sprayed onto a packing day 44 here.
  • a partial flow via line 50 is withdrawn from the circulating flow of the liquefied condensate from the first condensation stage.
  • This partial flow is at least partially supplied by means of the pump 51 via line 53 to the membrane separation system 55 with the semi-permeable membrane 57.
  • a portion of the liquid material drawn off over 50 can - but does not have to - be fed by means of the pump 52 via line 54 to a second membrane separation stage 56 with the semipermeable membrane 58.
  • the two membrane separation stages 55 and 56 can thus be connected in series or at least partially operated in parallel.
  • the condensate stream introduced via line 53 into the membrane separation stage 55 is divided into the two sub-streams permeate and retentate.
  • the permeate leaves the membrane separation stage via line 59 by means of pump 60 and is returned to the top of the washing column 46 via line 61 and is sprayed here, for example by means of spray nozzles 62, onto the packs or feed bodies 47.
  • the retentate from separation stage 55 is drawn off by means of line 63. It can be partly recycled in the circuit to the same membrane separation stage via pump 51 and line 53, but at least partially this retentate flow is fed into the downstream membrane stage 56 by means of the pump 52 via line 54.
  • the permeate after passing through the semipermeable membrane 58, leaves this separation stage via 64 under the influence of the pump 65.
  • the retentate from this second separation stage is drawn off via 76. It can be partly returned to the same separation stage via pump 52 and line 54, but at least partly it is drawn off via 77 and can then for example, the recycling of the organic components isolated here.
  • the parallel operation of the two separating devices differs from the description given so far only in that the cooled vapor partial current drawn off via line 50 is simultaneously fed to the two separating devices 55 and 56 under the action of the pumps 51 and 52 and worked up therein.
  • a further processing of the permeate stream 64 or 66 drawn off from the separating device 56 is provided.
  • the temperature provided for the subsequent third membrane separation stage in the aqueous-based liquid stream to be worked up is set via the heat exchanger 68.
  • the pump 69 the liquid flow is introduced via line 70 into the membrane separation stage 71 with the semi-permeable membrane 72.
  • the permeate passing through the membrane is drawn off via 73 and can, for example, be drained into the waste water.
  • the retentate of this separation stage 71 is removed via line 74. It can again be partly returned to this membrane stage by means of pump 69 and line 70, at least partly and preferably predominantly it is disposed of via line 75.
  • the organic components now enriched can be recycled.
  • any non-condensable gaseous constituents present in the feed vapor stream 34 are disposed of from the top of the washing column 46 via line 78, it being possible, if desired, for individual measures to be used, such as are shown in connection with the corresponding disposal of a non-condensable gas constituent in FIG. 1 .
  • FIG. 3 shows the previously mentioned modification of the method according to the invention, in which, in a partial precondensation, particularly easily condensing portions of the product are separated from the vapor stream beforehand and thus its further multi-stage treatment is removed.
  • the vapor stream supplied via line 79 by means of a fan 80 is fed to an indirect heat exchanger 81 leads in which the particularly rapidly condensing portions are converted to the liquid phase and removed from them via 84.
  • the still vaporous portion of the vapor stream is fed via line 82 to the washing column 83 in the lower part and here enters the countercurrent to the liquid phase, which is fed in at the top of this washing column via 94 and sprayed onto the packing or packs 95.
  • the liquid phase collecting at the foot of the washing column 83 is removed via line 85 and, like the first condensate from the partial condensation via line 84, is introduced into the storage container 86.
  • the stable liquid emulsion phase 87 collects in this storage container and is covered by the separating, at least predominantly organic, components 88, which are drawn off via 89.
  • the emulsion condensate is drawn off at the bottom of the storage tank 90 by means of the pump 91 and fed to the indirect heat exchanger 92.
  • the corresponding information in FIG. 1 applies again, there heat exchanger 10.
  • the cooled vapor condensate stream can be partly returned to the top of the washing column 83 via lines 93 and 94.
  • this cooled vapor condensate stream is fed to the membrane separation stage 99 by means of the pump 97 via lines 96 and 98.
  • the method can also be modified so that the cooled vapor condensate stream after passing through the indirect heat exchanger 92 is supplied in its entirety by means of the pump 97 to the membrane separation system 99.
  • the permeate passing through the semipermeable membrane 100 is drawn off via line 101 with pump 102.
  • This aqueous permeate can partly be returned to the top of the washing column 83 via lines 103 and 94, and at least partly it is removed from the circuit via lines 104 and 106 - after the condensate temperature in the heat exchanger 105 has been regulated again.
  • the retentate of the membrane separation system 99 is withdrawn via line 107. It can be partly returned to the separating device via lines 96 and 98. At least partially, however, this retentate is withdrawn from the circuit via line 108.
  • the orga- African components of the vapor stream to be cleaned can be recycled in any manner. Possibly non-condensable gaseous fractions also accumulate in the top of the washing column 83 and are drawn off there via line 109. The more specific details of the corresponding preparation of the inert gas portion from FIG. 1 again apply here in detail.
  • the aqueous slurry is fed to the spray drying in such an amount that the vapor part stream to be separated off and worked up is obtained in an amount of 7.6 kg / h.
  • Circulation narrow of the liquid vapor condensate flow 283.5 1 / h
  • a floating liquid phase of organic components forms in an amount of about 0.5% by weight of the total condensate (water content about 14% by weight), the main constituents of which are fatty alcohols, on the surface of the liquid vapor condensate which collects below in the washing column Chain lengths are C12 to C20.
  • the main components of this floating organic liquid phase are determined as follows:
  • Ci2 ⁇ fatty alcohol 0.6% by weight
  • Ci4 fatty alcohol 2.0% by weight
  • Cjö fatty alcohol 24.9% by weight
  • Cig fatty alcohol 41.4% by weight
  • the organic constituents and in particular the fatty alcohols also present here are present in a stable emulsified form.
  • the following numerical values apply to the composition of this aqueous lower phase:
  • Ci4 fatty alcohol 0.001% by weight
  • C ⁇ 6 fatty alcohol 0.006% by weight
  • Cig fatty alcohol 0.009% by weight
  • the lower emulsified phase is in the form of a milky emulsion. It is subsequently concentrated using microfiltration, the fatty alcohols being recovered in a concentrated form.
  • the permeate obtained in this microfiltration is a completely clear aqueous liquid phase.
  • a monolithic, inorganic membrane of the "Kerasep TM" type from Tech-Sep is used.
  • the basic body consists of Al2Ü3 / Ti ⁇ 2 and has a diameter of 22 mm.
  • This support body contains 19 membrane n ⁇ Te (MuTti-ChanneT module).
  • the diameter of each membrane channel is 2.5 mm. With a module length of 856 mm, this results in a membrane area of 0.12 m 2 .
  • a membrane with a 0.2 ⁇ m cut-off limit was selected for the filtration.
  • the condensate is concentrated by partial recycling in a ratio of 1:40.
  • the COD values of the permeate flow are in the range from 200 to 300 mg / 1 and are practically independent of the concentrating organic load of the emulsion phase supplied to the microfiltration.
  • a detergent formulation was dried by means of superheated steam, the anionic surfactants of which consisted of fatty alcohol sulfates (predominantly the chain length Ciss-Ciß).
  • the evaporation rate averaged 8 kg / h.
  • the excess vapors were withdrawn from the circuit at 120 ° C. and totally condensed in the condensation column according to FIG. 1. The plant was operated as follows:
  • Vapor quantity (1) 12 kg / h (incl. 4 kg / h propellant steam for a two-component nozzle)
  • Circuit condensate flow (9) 290 1 / h condensation temperature before WT (9) 97 ° C condensation temperature after WT (11) 75 ° C in (6) org.
  • Upper phase approx. 12 g / h (water content: 14%)
  • the amount of condensate discharged (17) was further cleaned in a microfiltration (21).
  • the microfiltration was carried out at a condensate temperature of 85 ° C.
  • the organic load on the permeate stream (23), measured as chemical oxygen demand, COD was 215 mg / l. Based on the vapor flow at the entrance to the column, this is a reduction of 95%.
  • the load on the retentate (27) was 16,600 mg / 1 COD (initial value of the condensate: 830 g / 1).
  • a detergent formulation was dried with superheated steam, in which ATkyTbenzoTsuTfonate aTs anionic surfactants were used.
  • the excess vapors were again condensed out in the condensation column shown in FIG. 1.
  • the operating conditions corresponded to Example 2, but the upper phase separated in the kettle sump (6) was only removed at the end of the test because of the very small amount.
  • the condensate flow (8) in the membrane system is cleaned at approx. 80 ° C.
  • the following parameters were set or measured:

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Water Supply & Treatment (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Organic Chemistry (AREA)
  • Nanotechnology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Wood Science & Technology (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)

Abstract

L'invention concerne un procédé optimisé de retraitement d'un courant de vapeur surchauffée chargée en constituants organiques pouvant être entraînés par la vapeur d'eau, par condensation de la phase vapeur avec récupération de la chaleur dégagée lors de la condensation et par séparation au moins proportionnelle des constituants organiques pouvant être entraînés par la vapeur d'eau qui proviennent du condensat aqueux. Ce procédé comprend une première étape d'échange d'énergie au cours de laquelle le courant de buées acheminé en continu est transporté conjointement dans le circuit avec un courant liquide réfrigéré et recyclé de buées condensées. Lors d'une seconde étape consécutive de transfert d'énergie, la chaleur est extraite indirectement du courant liquide chauffé. Un courant partiel est prélevé du circuit liquide des buées condensées et est soumis dans un processus du type faisant appel à une membrane, à une séparation de substances, le courant liquide résideul étant renvoyé dans le premier étage de travail. L'invention concerne l'utilisation de ce mode de travail pour des applications à grande échelle, notamment pour la séparation de mélanges de substances organiques à l'aide de vapeur surchauffée et/ou pour le séchage de préparations de substances aqueuses à l'aide de vapeur d'eau surchauffée faisant office de gaz de séchage.
EP95906986A 1994-02-01 1995-01-23 Procede optimise de retraitement de courants de buees a base de vapeur d'eau Withdrawn EP0741599A1 (fr)

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DE4402883A DE4402883A1 (de) 1994-02-01 1994-02-01 Optimiertes Verfahren zur Aufarbeitung von wasserdampfbasierten Brüdenströmen
DE4402883 1994-02-01
PCT/EP1995/000228 WO1995021010A1 (fr) 1994-02-01 1995-01-23 Procede optimise de retraitement de courants de buees a base de vapeur d'eau

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JPH09508568A (ja) 1997-09-02
WO1995021010A1 (fr) 1995-08-10
DE4402883A1 (de) 1995-08-03

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