US2606156A - Deaeration and drying of watersoluble sulfonated detergent compositions - Google Patents

Description

Aug. 5, 1952 2,606,156

E. DAVIS DEAERATION AND DRYING OF WATER-SOLUBLE SULFONATED DETERGENT COMPOSITIONS Filed June 9, 1950 MIXER EUTRALIZER AERATOR RECEIVYER WEIGH TANKS SPRAY DRYER IN V EN TOR.

Patented Aug. 5, 1952 DEAERATION DRYING OF WATER- SOLUBLE SULFONATED DETERGENT I ccnrosmoss EarliDavis, Whittier, Calif., assignor t01Purex Corporation,,Ltd South Gate, Calif., a combration of- California Applicatieniune 9, 1950, Serial No. 167,086

9 Claims- (c1; 2s2- -1c1) This invention has to do generall with the manufacture of detergents suitable for use as washing compounds, and particularly with the production of such compounded detergents by methods having for" their major object to give to the final and marketable products d'esirablesolm bility properties and high bulk densities. While applicable broadly to the manufacture ofdetergent compositions ingeneral and whose densities are subfiect to increase by deaeration of a dry'able slurry containing the detergent, the invention will be described typically, though as illustrative only, with reference to detergents containing as active ingredients the alkali metal salts of organic 'sul- -fonates and sulfates having such molecular structures as'to possess detergent properties.

It has been customary the manufacture-of such detergents to produce'firs't an aqueous slurry of the alkali metal organic sulfonates or sulfates, to which are added one or more salts or additives such as soda ash, sodium bicarbonate, alkali metal silicate, borax, sodium sulfate, sodium chloride, fullers earth and the like, to produce a mixture orslurr-y dr'yaole to any final form, e. g. as by spray drying, drum'drying, or tray drying. Considering spray drying as typical,- it is desirable that the solidgranules resulting from spray drying of the slurry, have a high bulk density, say upward of 0.40or above. Now by the usual methods of slurry treatment. and dehydration, potentially high bulk densities of final product either are not obtainable, or can be reached only as a result of relatively inconvenient and prolonged procedures. V

7 It is found that lower densities of the final product generally are .due to the presence of air in the mixture or slurry to be dried, and to the retention of the air in the dried product, as in the case of spray dried granules wherein the entrapped air tends to expand the particles and therefore lower their bulk density. My general object is toprovide a simple and emiently practical method-whereby in continuous operation an aeratedslurry may be quickly and efiectively deaerated to the degree desired, and the deaerated slurry thenvdehydrated and dried, as by a final spray drying operation. I

- In accordance withthe invention, a slurry containing any suitable alkali metal sulfonates orsul fates possessing detergent properties, (for example as more fully developed in a copending Stoneman application Serial Number 167,642,

.filed' June 12, 1950), may be mixed with any of such solid additives as the -builders and fillers referred toabove, Merely as illustrative, the

organic detergent components of the slurry may include or consist of compounds of the general formula R,SO2-OH, wherein R. is any benzenoid hydrocarbon radical having two or more replaceable nuclear hydrogen atoms (as derived frombenzene, toluene or xylene), and at least one nuclear hydrogen atom replaced by aliphatic or alicyclic radical containing 8 to 18 carbon atoms. Examples are the alkali metal salts of n-dode'cyl benzene sulfonic acid, n-dodecyl toluene sulfonic acid, undecane-Z-benzene sulfonic acid, and in generalv mixtures of this class in which t s a is; c r on alkyl radical isderived frorn aliphatic or alicyclic compounds of either straight or branched, symmetrical or non-symmetrical structure, such as may be foundin ledpetroleum fractions or in other naturally H I, 7 ng substances. Other contemplated detergets mentioned also in the Stoneman application) include the sultonic and sulfuric acid derivatives ofthe 8-18 carbon atoms olefins, alcohols, fatty acids, alkyl halides, and esters in the alipha-te or alicyclic series and mixtures thereof, Generally, the slurry to be deaerated prior to. drying rnay be characterized with respect; to its 3 active content as containing an .lanionic or mixture thereof, in the class of organic ,sultonates or sulfates containing an aliphatic or iiJiQYQli? ar W 5K 3 m b attached to an aromatic ring, with the aliphatic or alipart being derived irorn compounds contai-ning 8-13 carbonatoms and capableof either direct reaction to the sulfates or sulfonates, or indirect reaction by combination with an aromatic ring part or radical.

Deaeration of the slurry preparatoryto drying,

is accomplishedby passingthe slurry through azone maintained under subatmospheric pressure and within a range that may be regulated in accordancewith the degree of deaeration desired. Typically, the deaeration chamber is main- ;tained at an absolute pressure within the range of about to 250 mm. As will appear, the invention contemplates an uninterrupted process wherebythe admixed slurry and additives may be passedcontinuously from the mixer and .thencethrough the deaerator to the spray drier.

mar object-of the invention is to make higher density final products from a slurry pro duced bythe method of my copending application referred to above, accordance with which the I alkali metalorganicsulfonate results from neutralizationunder low pressure and under conditionssueh that the neutralized slurry going into the mixer, has been subjected to eiiective preliminary deaeration. When operated in conjunction with this low pressure process of neutralization, the bulk of the air removed in the final deaeration stage is that introduced into the slurry in the mixing operation.

All the features and objects of the invention, as well as the details of an illustrative embodiment, will be more clearly understood from the following detailed description of the accompanying drawing illustrating a typical procedure diagrammatically and in flow sheet form:

While it is to be understood that in the broad contemplation of the invention, the slurry to be subjected to final deaeration preliminary to drying, may be produced in any suitable manner, there are advantages in so treating a slurry which has been subjected to prior deaeration during and as a result of a low pressure neutralization stage. For more complete details concerning the low pressure neutralization of a suitable sulfated or sulfonated detergent stock, reference may be had to the copending Stoneman application referred to above. For present purposes, it will suflice to refer to the neutralizing stage, generally indicated at H], as comprising a neutralizing chamber ll evacuated through head [2 connecting with a vacuum pump or steam ejector to maintain in the chamber an absolute pressure within the range of about 9 to 88 mm. of mercury and at a corresponding water vapor temperature range between about 50 to 120 F.

Chamber ll communicates through line 13 with one or the other of the closed weigh tanks 15 and i 6 which, should line 13 form a direct and unrestricted passage, are located below the neutralizer a distance such that the communication between the neutralizer and tank constitutes a barometric leg. This distance may be shortened by placing in line I3 a pump 11, the displacement rate of which is suflicient to permit maintenance of the stated low pressure in the neutralizer. At the start of the neutralizing operation, one or the other of the tanks 15 and I6 is charged with a weighed quantity of alkali, preferably caustic soda solution, a stream of which is constantly circulated through line II! by pump 18 into a header I9 communicating with circularly arranged spray nozzles 20 in the head of the neutralizing chamber. The sulfonated hydrocarbon stream is fed at a predetermined rate through line 2| into a second header 22 which also connects with the spray nozzles 20. The sulfonic acids and alkali are premixed, reacted and sprayed into the neutralizer, and the resulting solution or slurry is taken through line l3 to the weigh tank. This cycle of alkali and slurry recirculation from the tank to the spray nozzles continues until a predetermined and stoichiometric quantity of the acids is neutralized by reaction with the alkali in the neutralizer. The neutralized slurry finally is withdrawn from tank l or 16 through line 24 for delivery to the mixer 25.

Suitable solid builders or flllers are added through inlet 26 to the slurry in the mixer and the components are subjected to thorough mixing as by a mechanically driven agitator diagrammatically indicated at 21. From typical operating data, it is found that the specific gravity of the neutralized slurry going to thei mixer may be within the range of about 0.84 to 1.14. The sulfonated slurry after compounding with the additives in the mixer and containing for example 8 to 27 by weight of the neutralized active detergent, has an increased density with-' in the range of about 1.15 to 1.20. This slurry then is continuously withdrawn from the mixer through line 28 and discharged by pump 29 into a deaerating chamber 30 preferably in flnely divided or sprayed form, as through a spray nozzle 3| in the head of the chamber. The latter is connected through line 32 with a suitable evacuator, so that the deaerator is operated under a pressure considerably below atmospheric pressure, and typically within the range of 50 to 250 mm. absolute. Ordinarily the temperature of the compounded slurry will be approximately atmospheric temperature. Being dispersed in finely divided form within the evacuated zone, the compounded slurry is effectively depleted of its air content, as well as some moisture, in accordance with the pressure existing in the deaerator, and its density is brought within the range of say 1.20 to 1.44.

The deaerated slurry is continuously withdrawn from the deaerator through line 33 and is discharged by pump 34 into a suitable drier 35, preferably of the spray type within which the slurry is reduced to finely divided form and dried by contact with hot gases or air, resulting in the production of the detergent as granulized particles. As previously indicated, the primary effect and advantage of the deaeration is the production of granules having higher bulk densities, this property apparently being due to the fact that whereas ordinarily the presence of air in the slurry being spray dried tends to remain entrapped and to expand therein, thus enlarging the hollow globular particles and thinning the shells, preliminary removal of the air in ac- ;-to produce the detergent in solid form.

2. The method of producing an increased density detergent of the class consisting of synthetic anionic sulfated and sulfonated water soluble detergents, that comprises subjecting an air-containing fluid aqueous slurry of the detergent to deaeration, without drying at an absolute pressure between about 50 to 250 mm. of mercury in one zone, and then drying the deaerated fluid slurry in another independent zone to produce the detergent in solid form.

3. The method of producing an increased density detergent from an air-containing fluid slurry thereof of the class consisting of synthetic anionic sulfated and sulfonated water soluble detergents, that comprises deaerating, without drying the slurry by' dispersing the slurry in divided and extensively exposed surface within a zone maintained at subatmospheric pressure. continuously withdrawing the deaerated slurry from said zone into a second zone, and then spray drying the fluid deaerated slurry in said second zone to produce the detergent in solid granular form. a

4. The method of producing an increased density detergent of the class consisting of synthetic v anionic sulfated and sulfonated water soluble detergents, that comprises mixing solid additives with and thereby entraining air in an aqueous slurry of the detergent in a first zone, subjecting the resulting mixture to deaeration and partial dehydration, but without drying, at subatmospheric pressure in a second zone by dispersing the slurry in extensively exposed surface form into the evacuated atmosphere of the second zone and then spray drying the deaerated mixture in a third independent zone.

5. The method of producing an increased density detergent of the class consisting of synthetic anionic sulfated and sulfonated water soluble detergents, that comprises mixing solid additives with and thereby entraining air in an aqueous slurry of the detergent in a first zone, subjecting the resulting mixture in divided and extensively exposed surface form to deaeration, without drying at an absolute pressure between about 50 to 250 mm. of mercury in a second zone, and then spray drying the deaerated mixture in a. third independent zone.

6. The method of producing an increased density detergent of the class consisting of synthetic anionic sulfated and sulfonated water soluble detergents, that comprises mixing solid additives with and thereby entraining air in an aqueous slurry of the detergent in a first zone, deaerating the mixture, without drying it, by spraying a, slurry of the mixture within a second zone maintained at subatmospheric pressure, and continuously withdrawing and spray drying the deaerated slurry in a third independent zone.

'7. The method of producing an increased density product detergent from an aqueous slurry of an alkali metal alkyl aryl sulfonate detergent. that includes mixing solid additives with said slurry in a first zone under conditions tending to aerate the slurry and thereby producing an aerated slurry having a density between about 0.95 to 1.20, deaerating, Without drying, said aerated slurry in a second zone to a degree increasing its density to within the range of about 1.20 to 1.44, and finally spray drying the deaerated slurry in a third independent zone.

8. The method of producing an increased density detergent product from a detergent of the class consisting of alkyl aryl sulfonates having a benzene radical to which is attached an aliphatic radical containing between 8 to 18 carbon atoms, that includes mixing solid additives with an aqueous slurry of the detergent in a first zone under conditions tending to aerate the slurry and thereby producing an aerated slurry having a density between about 0.5 to 1.20, deaerating, without drying, said aerated slurry in a second zone to a degree increasing its density to within the range of about 1.20 to 1.44, and finally spray drying the deaerated slurry in a third independent zone.

9. The method of producing an increased density product detergent of the class consisting of synthetic anionic sulfated and sulfonated water soluble detergents from an aqueous slurry thereof that,includes mixing solid additives with said slurry in a first zone under conditions tending to aerate the slurry, continuously discharging the serated slurry through a second zone maintained at subatmospheric pressure below 250 mm. absolute pressure and therein removing the bulk of the air content of the slurry without drying the slurry, continuously pumping the deaerated slurry from the second zone into a third zone, and spray drying the slurry in the third zone to convert the slurry to dry granu lized particles.

1 EARL DAVIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 19,456 Clayton Feb. 12, 1935 1,414,015 Godfrey Apr. 25, 1922 2,084,446 Lorenz June 22, 1937 FOREIGN PATENTS Number Country Date 61,127 Great Britain 1899

Claims (1)

1. THE METHOD OF PRODUCING AN INCREASED DENSITY SOLID DETERGENT OF THE CLASS CONSISTING OF SYNTHETIC ANIONIC SULFATED AND SULFONATED WATER SOLUBLE DETERGENTS, THAT COMPRISES SUBJECTING AN AIRCONTAINING FLUID AQUEOUS SLURRY OF THE DETERGENT

Images