DE4208773A1 - Drying wetting, washing and/or cleaning agent or component - Google Patents

Abstract

In drying wet wetting, washing and/or cleaning agents (IA) and/or components (IB) of these and their aq. solns. and/or suspensions with superheated steam (II), which is recycled after removing the fraction of water vapourised in the drying stage, (II) leaves the drying zone at a temp. of min. 150 (esp. min. 180) deg.C and the internal pressure of the (II)-filled system is at or esp. above normal to prevent air entering, e.g. at sites of damage, the internal pressure pref. being under ca. 50 mbar gauge. (I) may be zeolite cpds., esp. NaA zeolite. Pref. the starting material is spray dried through nozzle(s), e.g. with rotating discs, and the inlet temp. (Ti) of (II) is min. 250 deg.C. To produce high bulk density, Ti is min. 325, esp. min. 350 deg.C and the amt. (Wv) of water vapourised is min. 300 (esp. min.) 400 kg/m2.h w.r.t. the cross-section of the drying zone. To produce the bulk density, Ti is max. 280 deg.C and Wv is 100-250 kg/m2.h. In both cases, the (II) throughput is 1.0-4.0 (pref. 1.5-3.0, esp. 1.8-2.5) m3/m2.s. Additives (III) may be incorporated in the incompletely dry prod. to bind the residual water (partly), so that the dry prod. has storage-stable bulk and free-running property and (III) pref. are (partly) added to the aq. soln. or suspension before drying.

Description

The invention relates to a method for drying water-containing against valuable substances or mixtures of substances that are used as wetting, washing and / or cleaning agents and / or for use in such agents are suitable and can also be present as aqueous preparations, using superheated steam as the drying gas, the after discharge of the evaporated water in the circuit in the Drying level is returned.

To generate particles from an initially liquid product, ie from solutions or suspensions, come in technical application in particular spray drying, spray drying with integrated Fluid bed agglomeration and fluid bed spray granulation in question. Usually is used in the production of granules aqueous preparations of valuable materials of the type mentioned  Spraying on an industrial scale worldwide for decades drying used. Hot air or Mixtures of air and hot combustion gases are used. Textile washing powder as well as recyclable materials and mixtures for recycling of textile detergents in bulk and free-flowing powder form in so-called spray towers, usually in the area of the reverse pressure in countercurrent, more rarely in cocurrent, large technically won.

The advantages of the drying process using hot air among other things, the dry gas includes any available gaseous phase the possibility to work in open systems can, the disposal of the moisture-laden hot gas phase is technically possible by releasing it into the outside air chen. Intensive physico-chemical studies on the Ab course of the drying process have also shown that the Drying with hot air is comparatively milder even when used Hot gas temperatures run effectively and quickly. The drying process on wet particle sets largely independent of the The temperature of the hot gas used is comparatively never low temperatures - for example at temperatures of the particles of around 40 ° C - and settles under comparatively slower Increasing the particle temperature up to the boiling range of the water under normal pressure. Overall, the drying process runs in Hot air quickly and especially in the last drying stages effective, so that the recyclable materials become free-flowing goods when they dry are exposed to a comparatively mild temperature load.

Straight from the disadvantages and limitations of this type of procedure for the subject of drying addressed by the invention of recyclables or mixtures of recyclables from the areas of Tex Detergent and / or detergent is an example of that  the following points: Many of these recyclables are ins especially in the case of organic components - sensitive to oxidation. The treatment with hot air can be especially in the higher temperature rich lead to damage. The drying up pure or largely organic materials, e.g. B. of surfactants based on natural substances, creates significant problems from fire or even explosion Risk of dry goods. Important recyclable components, in particular Nonionic surfactants in the detergent range, show a more or less strong pluming tendency, d. H. on the transition from organic aerosols to the steam-laden exhaust air from the spray towers. Overall he exists increased risk of environmental pollution due to the large quantities of processed processed aqueous, solid and gaseous material and auxiliary materials fabrics. Considerations for recycling the drying gas flow have none in the commercial application of this process reaching precipitation.

In the earlier application DE-A 40 30 688 there is a method for winning of such finely divided, solid pourable or free-flowing value substances or mixtures of substances for wetting, washing and / or cleaning described from their aqueous preparations, being overheated ter steam used as a drying hot gas stream and thereby drying of the particulate material before it is endangered thermal action is canceled. If necessary the storage-stable bulk or free-flowing properties of such partially dried goods by adding such a mixture components ensured that bind limited amounts of water are qualified. In addition to or instead of this measure, a Post-treatment for homogenizing the residual moisture content in the parti kular good and / or its subsequent drying under preserving materials Conditions are connected.  

The invention described below relates to a targeted Ausge Organization of this procedure from the earlier application mentioned. Out For reasons of completeness of the disclosure of the invention is hereby the disclosure of this earlier application expressly also for Ge subject made the present disclosure of the invention.

In this context it should be borne in mind that the practical experience in the use of drying processes Use of superheated steam as a drying gas be very are limited, although this technology has inherently been the ses Century is known and repeated in the literature is written. The older patent application DE-A 40 30 688 settles with the relevant state of the art in print apart. On this information from the older application, be here referenced and only be the following publications named, which in turn has extensive bibliographies on this Field of work included: A. M. Trommelen et al. "Evaporation and Drying of Drops in Superheated Vapors "AIChE Journal 16 (1970) 857-867; Colin Beeby et al. "STEAM DRYING" Soc of Chem Eng, Japan, Tokyo (1984), 51-68 and W. A. Stein "Calculation of the Evaporation of liquid from moist products in the spray tower "Process engineering 7 (1973) 262-267.

A fundamental one for understanding the invention Difference between drying with hot air and drying with superheated Water vapor is striking: when working with the hot air flow the drying process starts at low product temperatures effective one. The water depletion is so out characterizes that when the material temperature of about 100 ° C is reached Drying is almost complete. For example, up to about 90% of the total water available at this time already carried out from the drop. The course looks completely different  the drop temperature when using superheated steam. By condensate sation of the superheated steam on the cooler feed and delivery of the Heat of condensation on the material to be dried finds a spontaneous one Heating of the aqueous drop to the boiling point of the water under working conditions, i.e. when working under normal pressure to temperatures of around 100 ° C. This boiling temperature is called Min minimum temperature during the entire drying period in the crop maintain. The respective loading of the aqueous phase with the leads to winning dry substances - depending on the dry Degree of drop - to individual deviations in tempera upwards at an earlier or later time.

In the process according to the invention, ge is accepted with conscious acceptance some restrictions regarding the drying result in the end product of the many advantages of hot exchange air through superheated steam in the fluidized bed spray granules tion method precisely in the tempera affected according to the invention door-sensitive items to be dried. As an essential ches element provides the invention here, residual moisture in the dry material tolerated, which - depending on the individual case - definitely can be considerable, but at the same time either given if necessary, auxiliary materials to be used and flowability of the granular material thus dried ensure and / or post-treatment z. B. a dressing gown provision. The auxiliaries can, as in the following is still described, in turn selected recyclables for the planned use or inert substances. According to the ge the compliance with the quality standards of the well-known com complex requirements for the More affected by the invention mixtures of substances based on organic and inorganic mixture com components - for example textile detergents - without loss of quality, however, while realizing the benefits of overheating drying Steam. Oxidation processes on endangered components of the  Wetting agents, detergents and cleaning agents are prohibited; Fire and Ex explosion risks are switched off. Since the drying steam in Circulation is dispensed with, the delivery of unwanted components into the ambient air. Only that from the material to be dried The resulting steam partial flow is discharged and requires Reini supply. Any shares of good that are carried along are utilized. Other technological advantages for the interpretation of the corresponding Appropriate facilities can be used.

The invention described in the earlier application DE-A 40 30 688 enables a procedure free of exhaust gas and loaded waste water management, but that to achieve certain product properties, such as B. the bulk density, are to be observed process parameters not known from it.

The invention is therefore based on the object of operating parameters for the procedure of the type mentioned above, which he possible, targeted products with certain properties, e.g. B. Bulk density.

This object is achieved in that with Steam exit temperatures from the drying zone of at least 150 ° C, in particular of at least about 180 ° C and with internal pressures of steam-filled system in the range of normal pressure, but ins special works with such raised pressures so that air inlet breaks, for example at damaged areas, prevented in the system system internal pressures below about 50 mbar overpressure are preferred.

With these outlet temperatures it is possible to recycle and Mixtures of materials of the type described above and also below to produce, the residual moisture is so low that only a little normal post-drying or "internal drying" is required or  can even be completely eliminated. Due to the slight overpressure possible deterioration in the quality of the products due to air ingress definitely excluded. Such ingress of air in the Steam-filled circulatory systems occur in conventional systems that with air as the drying gas and usually with a slight negative pressure work on damaged areas that are not in large-scale plants can be prevented.

Working in the area of normal pressure enables the comparison wise complication-free operation even in large-scale plants the required high material throughputs per unit of time. Since extraneous gas, especially air, into the circulatory system filled with water vapor cannot collapse, secondary damage is the target high-quality product quality thus reliably excluded. Suitable working pressures are in the range up to about 150 mbar moderately up to about 75 mbar and preferably below 50 mbar. The Be range from about 5 to 15 mbar system pressure is particularly imminent moves.

The method according to the invention is used in particular as an atomization drying carried out in a so-called spray tower, the Material to be dried with one or more nozzles, in particular single substance nozzles, rotary disc atomizers and / or other suitable Zer dusting equipment is finely divided. But also a vortex Layer spray granulation or spray drying with integrated Fluid bed agglomeration using superheated steam as Drying gas can be advantageously used with the mentioned steam operate temperature and system overpressure. The above mentioned The advantages apply accordingly.

To operate the process economically and to achieve ei sufficient drying speed and good drying result, the temperature of the cycle steam is maintained  Entry into the drying zone preferably to at least 250 ° C.

This is an important parameter that characterizes the dried material Bulk density. When drying the above-mentioned recyclables and Mixtures of recyclable materials with superheated steam are possible at Adherence to the procedure that makes sense for large-scale plants conditions set a range of bulk weights that the with air drying by at least about 10%, in special cases even by at least about 20%, both higher and never other bulk weights.

Specifically, the following areas are procedural parameters preferred.

To achieve a high bulk density, keep the temperature of the Circulation steam on entering the drying zone is preferred at least 325 ° C, especially at least 350 ° C. this applies especially for steam drying with atomizing nozzles. To make the temperature is set for products with low bulk density of the cycle steam is preferred when entering the drying zone to a maximum of 280 ° C. The terms "high bulk weight "and" low bulk density "compared to the forth conventional drying with products obtained using hot air, currently, depending on the recipe, bulk weights can have between about 250 to about 600 g / l. So "high Bulk density "the range of more than 300 to 400 g / l and" low bulk density "is less than about 400 g / l sen. In the case of formulations and procedures other than those currently customary Conditions accordingly include these terms in other areas.

It is also proposed that to obtain a product with a high bulk density with a water evaporation of at least 300, in particular at least 400 kg / m ² h, based on the cross-sectional area of the drying zone.

In order to obtain a product with a low bulk density, on the other hand, it is preferred to work with water evaporation from 100 to 250 kg / m ² h, based on the cross-sectional area of the drying zone.

In a further advantageous embodiment of the invention, both a drying performance which is sufficient from an economic point of view and a limitation of the filter load by discharging fine dust are achieved if the steam throughput is preferably from 1.0 to 4.0, in particular 1.5-3.0 1.8 to 2.5 m ³ / m ² s, based on the cross-sectional area in the drying zone, a.

The following is a more detailed explanation of general characteristics and other advantageous embodiments of the invention, which does not only relate to the setting of certain procedural parameters refer to.

An important embodiment of the invention is thus the waiver on the setting of optimal drying results by superheated steam action in the end product of the process. Residual moisture, also be pregnancy, can be tolerated if together of the goods is ensured by a kind of "interior Drying "this residual water is bound as far as possible det that the storage-stable pourability and flowability of the Troc good quality is guaranteed.

Requires the temperature sensitivity of the material to be dried or mixture of recyclable materials the retention of not inconsiderable what Amounts of water in the product of the main drying and, if necessary, the Binding of this residual water to ensure storage stability Bulk and free-flowing properties of the dry goods, so fiction used according to auxiliaries, preferably as a particulate solid  body are capable of water fixation. Such fixation of Residual water can be incorporated as a crystal, for example water. But also a purely absorptive bond limited amounts of water in solid particles of those affected Possible without causing undesirable stickiness or Adhesion of the particles to one another is effected. The excipients are used in at least such a sufficient amount that despite the the residual and storage stability in the residual moisture is guaranteed.

The auxiliary materials that bind the residual water can be in one version Form of the invention expediently the dried fresh material added immediately after its discharge from the drying container and thus be mixed intensively. In a preferred embodiment However, these auxiliaries take at least some form se, the aqueous solutions or suspensions even before feeding mixed into the drying zone. The latter is possible Embodiment whenever the respective temperature sensitivity of the material to be dried, such extensive drying lets the remaining residual moisture through to a sufficient extent such auxiliary substances used are absorbed and bound can.

In a preferred embodiment of the he The inventive method are used as residual water binding adjuvant corresponding materials from the area of wetting, washing and / or cleaning agents are used, which in turn are sufficiently tempe are insensitive to nature. Typical examples are crystal water-binding inorganic materials from the classes of builders Components, the washing alkalis and / or the so-called adjusting agents, e.g. B. crystal water-binding silicate compounds, in particular Zeo lithe. A particularly characteristic for textile detergents  Today, the detergent-quality zeolite NaA is one game Calcium binding capacity in the range of 100 to 200 mg CaO / g - compare che the details of DE 24 12 837. Examples of crystal water Serum binding alkalis are soda or sodium bicarbonate, while Sodium sulfate as a neutral salt or adjusting agent considerable amounts can bind to crystal water. In addition to or instead of such auxiliary can bind substances with the ability to bind water of crystallization the residual water also by means of auxiliary materials or appropriate materials can be used with the ability to absorb water. It is known that known graying inhibitors on starch or cellulose-based, textile softening aids, in particular based on inorganic, swellable silicates, but also a number of organic surfactant compounds that are solid under normal conditions can absorb significant amounts of water without using an un desired surface tack to respond to.

Depending on the temperature sensitivity of the recyclables used or mixtures of materials on the one hand and the nature and quantity of auxiliary materials used on the other hand can have considerable residual water contents remain in the dried goods without their la to endanger tannable bulk and pourability. Invention is therefore provided for drying with superheated water steam at residual water content from the fluidized bed Abort good in the range of about 1 to 20 wt .-%, the rest water contents in the range of about 5 to 15% by weight are preferred. The ranges given here refer to the weight of the material discharged from the drying zone. According to the invention further preferred, the proportion of this residual water that is not considered Water of crystallization is bound, preferably to a maximum of about 10% by weight limit to no more than about 3 to 4% by weight. Here too applies to the% by weight of what has been said above.  

A particularly interesting embodiment of the invention sees the Recovery and recovery of the heat of condensation from the Cycle of ejected water vapor. Because of the engagement Suitable steps can also be the recycling of low proportions of recyclable materials are ensured, which exceed the flow of hot steam left the primary circuit of the steam have. Here, for example, using the condensate tion heat of the discharged steam portion worked as follows will:

In a preferably multi-stage evaporation plant is used the heat of condensation of the subtracted steam the steam concentrated condensate. The remaining concentrate is returned to the primary process circuit. In particular can this residual concentrate is to be dried by superheated superheated steam Recycled slurry are added.

If necessary, condensation from the primary cycle of discharged superheated steam if necessary falling residual gas phase loaded with the smallest amounts of recyclable material subsequent processing step - for example a scorch treatment, treatment in biofilters or in washing systems will. By such a combination of measures of a practical complete recycling of the respective partial flows and the This enables the reliable destruction of the last traces procedures in accordance with the work area concerned here are large technical production for the first time the possibility of valuable materials and value Exhaust air mixtures of substances from the field of washing and cleaning agents can be extracted free and free of loaded wastewater.

In addition to or instead of using to bind the residual water The invention further provides for qualified auxiliary substances aftertreatment  of the primary accumulated, partially dried granules, if the residual moisture of the dried goods is still too high. The Nachbe is realized through two technical concepts, the can also be connected to each other.

The first of these conceptions assumes that the individual Degree of drying of the particle concerned from its part size is determined. According to the invention, the drying process canceled at a time when there were still considerable quantities of residual moisture in the goods, then an integral consideration the residual moisture content only partially meets reality. In the differential consideration of the distribution of this residual moisture It can be seen from the individual shares that the fine relationship very fine or very dry can be while the coarser good parts are still so moist, that a storage-stable bulk and pourability for the Fluid bed removed material is not yet ensured. In a important embodiment of the method according to the invention correspondingly a "post-drying" of the primary material from the dry zone by an additional, at least one-stage post-treatment action step achieved - without the powdery good of one Suspend exposure through gluing - to homogenization the moisture content of the total good regardless of the individual len particle size leads. In this way, the ver equally coarser moist parts of the goods so much rest moisture can be transferred into the fine and very fine material that after the the storage-stable bulk and trickle Ability of the dry goods are guaranteed without it additional discharge of additional amounts of moisture from the bulk material may.

All procedures are necessary to achieve this post-treatment stage  techniques appropriate to the moisture content of each part kel while preventing sticking of the mass compensate. Circulation and mixing are only examples here or shaking the primary product in continuous or called discontinuous processes. Can be particularly suitable an aftertreatment of the goods in a downstream fluidized bed be.

Here, with any gases, preferably with ambient air, worked. Oxidative material hazards and undesirable pollution Exhaust air cleaning does not occur or hardly occurs here are easy to master. Since the material to be dried is the fluidized bed with elevated temperature - usually in the range of about 105 ° C - can be removed via such a downstream moisture homogenization in a fluidized bed still a little too additional reduction in residual moisture can be achieved.

In addition to or instead of such an auxiliary measure in the Invention according to the method but also an additional drying in one or several stages are provided to further reduce the residual moisture be. It is characteristic of post-drying that here under Conditions are worked, which are the recyclables of the dry material not harm. As an example of process parameters for risk reduction are mentioned: lowering the temperature of the hot gas phase, Avoid superheated steam as a hot gas and replace it by drying gases of other origin, for example air and / or Inert gas and transition to another drying technology.

Are particularly suitable for use in the method according to the invention dere aqueous preparations of such valuable materials and material combinations ions from the field of wetting, washing and / or cleaning agents, caused by short-term exposure to water or water vapor in the  Range of a product temperature of 100 to 120 ° C not or not we be significantly damaged. Are particularly suitable as a value fabric components Components of this type, which are included in the working area conditions the specified temperature range for at least one Period of about 5 s to 5 min. Survive harmless. Crucial is that the period of this temperature exposure in the invention essen procedure is kept so short that under the selected Ar working conditions substantial damage to the goods to be dried not yet occur. For example, hydroly Surfactant compounds at risk under these working conditions Ver because periods of a few seconds to a few minutes largely survive unscathed, if certain, to the relevant specialist known framework conditions are observed. So it becomes possible that aqueous preparation in the drying process according to the invention gene water-soluble and / or insoluble organic and / or anor ganic materials from wetting agents, detergents and / or cleaning agents subject to drying, for example the following Substance classes can be assigned: Components with surfactant or emulsions door effect, inorganic and / or organic framework substances or Builder components, washing alkalis, adjusting agents or neutral salts, Fabric softeners, bleach activators, additives for improvement the dirt-carrying capacity of fleets such as graying inhibitors or abrasives.

In an important embodiment, the method according to the invention for drying mixtures of recyclable materials for building text detergents used. The aqueous application measure to be dried materials contain wash-active surfactants together with framework or builder substances, and if desired washing alkalis and / or neutral salts. At least part of the is used here multi-component mixtures for binding and / or fixing residual water water, especially in the form of crystal water. In such  As a rule, mixtures of fabrics will not be used in laundry detergents its entirety exposed to hot gas drying. The extreme Temperature sensitivity of peroxide-containing bleaching components, such as Perborate monohydrate or tetrahydrate and the like other particularly temperature-sensitive components do not allow this to. Enzymes, fragrances, bleach activators are further examples ren and other small components called. The invention also sees accordingly, among other things, the production of so-called multi-compos Nenten tower powder, which is a large part of the finished detergent constituent components combined in a mixture, subsequently Lich but still with liquid and / or solid further active ingredient com components are applied or mixed. Known examples of such liquid components are particularly volatile niotes Sidic components that are not in the process according to the invention are released into the environment via the exhaust gas, their addition to the Total detergent nonetheless by subsequently spraying on Absorbent granules prepared according to the invention simply out can be designed.

The following is general information on valuable materials for direct or indirect use in the production of wetting agents, detergents and / or cleaning agents using the working principles according to the invention, this compilation of today's common components of textile detergents being shown. For example, soaps made from natural or synthetic, preferably saturated, fatty acids can be used as anionic surfactants. Soap mixtures derived from natural fatty acids, for example coconut, palm kernel or tallow fatty acids, are particularly suitable. Be preferred are those which are composed of 50 to 100% of saturated C _12-18 fatty acid soaps and 0 to 50% of oleic acid soap.

Other suitable synthetic anionic surfactants are those of Type of sulfonates and sulfates. This can be particularly important Plant method according to the invention for corresponding compounds and / or of animal origin.

Suitable surfactants of the sulfonate type are alkylbenzenesulfonates (C _9-15 -alkyl), olefin sulfonates, ie mixtures of alkene and hydroxyalkane sulfonates, and sulfonates, such as those obtained from C _{12 18} monoolefins with a terminal or internal double bond by sulfonating Gaseous sulfur trioxide and subsequent alkaline or acidic hydrolysis of the sulfonation products. Also suitable are the alkanesulfonates which are obtainable from C _12-18 alkanes by sulfochlorination or sulfoxidation and subsequent hydrolysis or neutralization or by bisulfite addition to olefins, and in particular the esters of alpha sulfo fatty acids (ester sulfonates), e.g. B. the alpha-sulfonated methyl ester of hydrogenated coconut, palm kernel or tallow fatty acids.

Important surfactant or emulsifier components in this context are also the so-called di-salts, which can be prepared by saponification of the aforementioned alpha-sulfonated fatty acid methyl esters or by direct sulfonation of, in particular, saturated fatty acids - in particular C _12-18 fatty acids.

Suitable surfactants of the sulfate type are the sulfuric acid monoesters from primary alcohols of natural and synthetic origin, ie from fatty alcohols, e.g. As coconut fatty alcohols, tallow fatty alcohols, oleyl alcohol, lauryl, myristyl, palmityl or stearyl alcohol, or the C _10-20 oxo alcohols, and those secondary alcohols of this chain length. The sulfuric acid monoesters of alcohols of natural and / or synthetic origin ethoxylated with in particular 1 to 6 mol of ethylene oxide are also suitable components. Examples of synthetic alcohols are compounds such as 2-methyl-branched C _9-11 alcohols with an average of 3.5 moles of ethylene oxide. Sulfated fatty acid monoglycerides are also suitable.

The anionic surfactants can be in the form of their sodium, potassium and Ammonium salts as well as soluble salts of organic bases.

Addition products from 1 to 40 are nonionic surfactants. preferably 2 to 20 moles of ethylene oxide to 1 mole of an aliphatic Compound having essentially 10 to 20 carbon atoms from the Group of alcohols, carboxylic acids, fatty amines, carboxamides or Alkanesulfonamides can be used. The attachments are particularly important Products from 8 to 20 moles of ethylene oxide to primary alcohols, such as. B. on coconut or tallow fatty alcohols, on oleyl alcohol, on oxo alcohols or to secondary alcohols with 8 to 18, preferably 12 to 18 C- Atoms. In addition to the water-soluble nonionics, however, are also not or not completely water-soluble polyglycol ethers 2 to 7 ethylene glycol ether residues in the molecule of interest, esp especially when combined with water-soluble, non-ionic or anionic surfactants are used. In the method according to the invention The carryover tendency of such nonionic surfactants can be increased are taken into account that components of this type entirely or partially after the completion of drying with superheated steam on the obtained granules are applied. In particular, it can Valid for nonionic surfactants that are liquid at room temperature.

In addition, alkyglycosides of the general formula RO- (G) _x can also be used as nonionic surfactants, in which R is a primary straight-chain or branched aliphatic radical having 8 to 22, preferably 12 to 18 C atoms, G is a symbol which stands for a glycose unit with 5 or 6 carbon atoms, and the degree of oligomerization x is between 1 and 10.

As an organic and inorganic framework or builder sub punches are weakly acidic, neutral or alkaline de Soluble and / or insoluble components to remove the calcium ions fall or bind complex. Suitable and in particular Ecologically harmless builder substances are fine crystalline synthetic zeolites of the kind already described. As further Builder components, in particular together with the zeolites can be used, come in (co) polymeric polycarboxylates Consider, such as polyacrylates, polymethacrylates and copo in particular polymers of acrylic acid with maleic acid, preferably those with 50% up to 10% maleic acid. The molecular weight of the homopolymers is generally between 1000 and 100,000, that of the copolymers between rule 2000 and 200,000, preferably 50,000 to 120,000, based for free acid. A particularly preferred acrylic acid-maleic acid Copolymer has a molecular weight of 50,000 to 100,000. Suitable, albeit less preferred, compounds of this class are copolymers of acrylic acid or methacrylic acid with vinyl ethers, such as vinyl methyl ether, in which the proportion of acid is at least 50% is. Also useful are polyacetal carboxylic acids, as in for example in US Pat. Nos. 41 44 226 and 41 46 495 are written, as well as polymeric acids, which by polymerization of Acrolein and subsequent disproportionation using alkalis are kept and from acrylic acid units and vinyl alcohol units or acrolein units are constructed.

Usable organic builders are, for example, be preferably polycarboxylic acids used in the form of their sodium salts, such as citric acid and nitrilotriacetate (NTA), if such Use for ecological reasons is not objectionable.  

In cases where a phosphate content is tolerated, too Phosphates are used, in particular pentasodium triphosphate, optionally also pyrophosphates and orthophosphates contained in it act as a precipitant for lime salts.

Suitable inorganic, non-complexing salts are the bicarbonates, carbonates, borates or silicates of the alkalis - also referred to as "washing alkalis"; Of the alkali silicates, especially the sodium silicates with a Na ₂ O: SiO ₂ ratio of 1: 1 to 1: 3.5 can be used. From the remaining groups of conventional detergent components, components from the classes of graying inhibitors (dirt carriers), neutral salts and textile-softening auxiliaries are particularly suitable for use in the process according to the invention.

Suitable graying inhibitors are, for example, carboxymethyl cellulose, methyl cellulose, methyl hydroxyethyl cellulose and their Mixtures. As a typical example of a suitable representative of the Neutral salts include the sodium sulfate already mentioned. Ge Suitable plasticizers are, for example, swellable layered silicates of the type of corresponding montmorilonites, for example bentonite.

High-temperature-sensitive common mixture components of washing and cleaning agents, such as bleaches based on per-compound genes, enzymes from the class proteases, lipases and amylases or Bak strains or mushrooms, stabilizers, perfumes, temperature sensitive Liche dyes and the like, as already stated expediently mixed with the previously obtained granulate.

The following are examples and test results of the invention described according to the method, without the invention being is limited.  

Examples

In a pilot spray tower on a pilot scale of the "Minor Production" type from Niro-Atomizer with a cross-section of 1.13 m ² , a powder product, known as "tower powder", of a detergent was produced by spraying detergent slurry using rotary atomization in superheated steam. The detergent slurry contained 16% by weight of surfactants, about 20% by weight of soda as well as zeolite NaA, water glass, Sokalan (R) and the usual small components in the solid fraction. The water content of the slurry was 42% by weight. The pressure in the test facility was adjustable from 5 mbar negative pressure to 10 mbar positive pressure. The tests were carried out in the range from 1 mbar negative pressure to 2 mbar positive pressure, preferably at 0.5 mbar positive pressure.

For comparison, atomization tests with air as dry were also carried out Gas carried out.

First, the inlet and outlet temperature of the superheated water vapor was kept constant and the water evaporation was increased from 1.3 to 5.2 kg / m ² h. The outlet temperature was kept at approximately constant values by a corresponding increase in the steam throughput (Table 1). The water evaporation per unit area obtained in Table 1 is about two orders of magnitude lower than that of an industrial spray tower. However, if water evaporation is related to the tower volume, it is of the same order of magnitude. The dependence of the bulk density on the size of the water evaporation can be clearly seen without a significant change in the residual moisture. The size X50 also mentioned in Table 1 indicates the diameter, which is less than 50% of all particles.

For comparison, tests were carried out with air as the drying gas under otherwise identical conditions. At constant air inlet temperature and constant air throughput, the water evaporation was increased from 1.9 kg / m ² h to about double by increasing the slurry throughput. Only a slight, less than 10% increase in the bulk density and a slight decrease in the particle size were found here. On the other hand, when drying with superheated steam, the bulk density increased twice as much under otherwise identical conditions.

Experiments with rotary atomization were also carried out in order to achieve the Dependence of the bulk density and the particle size on the input and Outlet temperature with superheated steam and air as dry determination gas. A significant increase in bulk density and a decrease in particle size was seen in a decrease in the intake and Hot air outlet temperature determined as dry gas. Becomes however, dried with superheated steam, the bulk changes density and particle size with little change in on and off entering temperature of the drying gas, provided that the atomization of the Slurry is made with a rotating disc. Against will atomized in a nozzle (Table 2, Examples 8 to 11) so increases Bulk density with increasing inlet temperature. When using The reverse applies to air as the drying gas (Examples 12 to 16) te. A slurry was also used in Examples 8 to 16 of Table 2 a universal detergent of the recipe given above, but with an initial moisture of about 50% under otherwise the same conditions conditions atomized as in Examples 1 to 7.

Claims (21)

1. Process for drying water-containing materials or mixtures of materials which are suitable as wetting, washing and / or cleaning agents and / or for use in such agents and can also be present as aqueous preparations, using superheated steam as the drying gas, which is returned to the drying stage after the evaporated water portion has been discharged, characterized in that steam exit temperatures from the drying zone of at least 150 ° C, in particular at least about 180 ° C and with internal pressures of the steam-filled system in the range of normal pressure, but in this case works in particular with pressures raised in this way, so that air ingresses, for example at locations of damage, are prevented in the system, system internal pressures below about 50 mbar overpressure being preferred. 2. The method according to claim 1, characterized, that one carries out the drying as spray drying, whereby the material to be dried with one or more nozzles, in particular Single-substance nozzles, with rotary disc atomizers and / or others suitable atomizing devices is finely divided. 3. The method according to claim 2, characterized, that the temperature of the cycle steam when entering the Drying zone holds at least 250 ° C.   4. The method according to claim 3, characterized, that the temperature to achieve a high bulk density of the cycle steam as it enters the drying zone holds at least 325 ° C, in particular at least 350 ° C. 5. The method according to claim 3, characterized, that the tempera to achieve a low bulk density circuit steam when entering the drying zone holds at most 280 ° C. 6. The method according to any one of claims 2 to 5, characterized in that to obtain a product with a high bulk density with a water evaporation of at least 300, in particular at least 400 kg / m ² h, based on the cross-sectional area of the drying zone. 7. The method according to any one of claims 2 to 5, characterized in that to obtain a product with a low bulk density with a water evaporation of 100 to 250 kg / m ² h, based on the cross-sectional area of the drying zone. 8. The method according to claim 6 or 7, characterized in that the steam throughput is based on 1.0 to 4.0, in particular 1.5 to 3.0, preferably 1.8 to 2.5 m ³ / m ² s on the cross-sectional area in the drying zone. 9. The method according to any one of claims 1 to 8, characterized, that one is incomplete to at least partially bind the im dig dried product contained residual water auxiliaries uses, so that the storage-stable bulk and pourability of the dry goods is ensured, and these auxiliaries, too at least in part, the aqueous solutions or suspensions especially mixed before drying. 10. The method according to claim 9, characterized, that components as auxiliary substances for binding the residual water the wetting agent, detergent or cleaning agent, in particular builder, Used alkalis and / or adjusting agents. 11. The method according to any one of claims 1 to 10, characterized, that the drying with the superheated steam at rest water content in the range of about 1 to 20% by weight, in particular breaks off in the range of about 5 to 15 wt .-% and preferred show the content of free, not bound as crystal water Water based on values of at most about 10% by weight, in each case the weight of the material discharged from the drying zone, limited. 12. The method according to any one of claims 1 to 11, characterized, that the residual moisture content of the granules obtained in one homogenized at least one-step after-treatment step. 13. The method according to claim 12, characterized,  that the residual moisture content in a fluidized bed with air homogenized as fluidizing gas. 14. The method according to any one of claims 1 to 13, characterized, that the granules still containing residual water are undervalued conditions gentle to the material agglomerate and dry or aftertreated. 15. The method according to any one of claims 1 to 14, characterized, that aqueous preparations of such valuable materials or valuable material uses combinations that are caused by short-term exposure to Water and steam in the temperature range from 100 to 120 ° C not be damaged and at least this temperature range for a period of 5 s to 5 min. in the form of preparation used Survive harmless. 16. The method according to any one of claims 1 to 15, characterized, that aqueous preparations are water-soluble and / or insoluble organic and / or inorganic materials from wetting, Detergents and / or cleaning agents, such as components with tenside or emulsifier effect, inorganic and / or organic Ge builders or builder components, washing alkalis, Stellmit tel or neutral salts, fabric softeners, bleach activators, Auxiliaries to improve dirt-carrying capacity such as ver anti-graying and abrasive substances subject to the process. 17. The method according to any one of claims 1 to 16, characterized, that organic components selected as valuable materials  or inorganic in nature from the classes of surfactants or emuls gators or the builder or builder, in particular the field of valuable materials for textile detergents, as free-flowing dry goods can be obtained. 18. The method according to any one of claims 1 to 17, characterized, that mixtures of valuable materials for the construction of textile detergents be dried, the surfactants together with framework or Builder substances and, if desired, washing alkalis and / or Contain neutral salts, with some of the multi-component mixtures is capable of binding and / or fixing residual water. 19. The method according to any one of claims 1 to 18 for the production of free-flowing surfactant solids, especially anionic surfactants based on natural substances, especially when mixed with soluble Chen inorganic salts to ensure the pourability and / or the bulk density are present. 20. The method according to any one of claims 1 to 18 for the production of dried silicate-based hosts, particularly in Textile detergents can be used and correspond appropriate swellable and / or non-swellable representatives such as Layered silicates and / or zeolite compounds, in particular Zeo lith NaA in detergent quality. 21. The method according to any one of claims 1 to 18 for the production of Textile detergent tower powders, to which temperature-sensitive and / or steam-volatile components to build the finished Textile detergents can be added.