Ind. Eng. Chem. Res. 1988,27, 1291-1296
Nomenclature Ca = p U / u , bubble capillary number CaT = pUT/u, bubble capillary number in straight section of the capillary d = density of mineral oil, kg/m3 F = denotes general function g = acceleration of gravity, m/sz Ho= film thickness deposited by bubble, m i.d. = internal diameter of glass capillaries, m L = initial upstream bubble length, m Lb = bubble length generated by snap-off, m nDZo= refractive index Oh = p / ( p ~ R ~ Ohnesorge ) ~ / ~ , number PL= liquid pressure, Pa Pc = gas pressure, Pa PL1= liquid pressure at point 1, Pa PL2= liquid pressure at point 2, Pa r = radial position, m F = r / R T , dimensionless radial position Rneck= radius of pore neck, m RT = radius of unconstricted capillary, m R1,2,3 = radii of curvature, m t = time, s t b = time to breakup, s U = instantaneous velocity of bubble front, m/s Uchar= characteristic velocity of bubble jump, m/s UT = velocity of bubble front in straight section of the capillary, m/s x = axial position relative to constriction neck, m 2 = x/RT, dimensionless axial position Greek Symbols X = rPmwd/RT,dimensionless radial position of the pore wall p = viscosity of wetting liquid, mPa.s r = 3.141 59 p = density of wetting liquid, kg/m3 pgas = density of gas in the bubble, kg/m3 u = surface tension, mN/m 7 b = t b / ( 3 p R T / u ) dimensionless , time to breakup Tsurfactanta = t b / ( 3 p R ~ / u dimensionless ), time to breakup for
surfactant solution
Literature Cited Adamson, A. M. Physical Chemistry of Surfaces; Wiley: New York, 1976. Bretherton, F. P. J. Fluid Mech. 1961, 10, 166.
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Carnahan, B.; Luther, H. A.; Wilkes, J. 0. Applied Numerical Methods; Wiley: New York, 1969; p 63. Dilgren, R. E.; Deemer, A. R. Presented a t the SPE California Regional Meeting, San Francisco, March 24-26, 1982; SPE 10774. Falls, A. H.; Gauglitz, P. A.; Hirasaki, G. J.; Miller, D. D.; Patzek, T. W.; Ratulowski, J. Presented at the SPE/DOE 5th Symposium on EOR, Tulsa OK, April 20-23, 1986; SPE 14961. Fried, A. N. “The Foam-Drive Process for Increasing the Recovery of Oil”; U. S. Department of the Interior, Bureau of Mines R. I. 5866, 1961. Friedmann, F.; Jensen, J. A. Presented a t the SPE California Regional Meeting, Oakland, CA, April 2-4, 1986; SPE 15087. Gauglitz, P. A. Ph.D. Thesis, University of California, Berkeley, 1986. Gauglitz, P. A.; St. Laurent, C. M.; Radke, C. J. J . Pet. Technol. 1987, 39(9), 1137. Goldsmith, H. L.; Mason, S. G. J . Fluid Mech. 1962, 14, 42. Goldsmith, H. L.; Mason, S. G. J. Colloid Sci. 1963, 18, 237. Hammond, P. S. J. Fluid Mech. 1983, 137, 363. Hirasaki, G. L.; Lawson, J. B. Soc. Pet. Eng. J . April 1985, 176. Hornbeck, R. W. Numerical Methods; Quantum: New York, 1975. Levich, V. G. Physicochemical Hydrodynamics: Prentice-Hall: Englewood Cliffs, NJ, 1962. Mast. R. F. Presented at the 47th Annual Fall Meetine of SPE. San Antonio, TX, 1972; SPE 3997. Morrow, N. R. Ind. Eng. Chem. 1970, 62, 32. Owete, 0. S.; Brigham, W. E. “Flow of Foam Through Porous Media”. SUPRI TR-37, July 1984; Stanford University Petroleum Research Institute, Stanford, CA. Park, C. W.; Homsy, G. M. J . Fluid Mech. 1984, 139, 291. Perry, J. H. Chemical Engineers’ Handbook, 3rd ed.; McGraw-Hill: New York, 1950. Ploeg, J. F.; Duerksen, J. H. Presented at the California Regional SPE Meeting, Bakersfield, March 27-29, 1985; SPE 13609. Ransohoff, T. C.; Radke, C. J. SPE Reservoir Eng. 1988, in press. Ransohoff, T. C.; Gauglitz, P. A.; Radke, C. J. AIChE J . 1987,33(5), 753. Roof, J. G. Soc. Pet. Eng. J. 1970, 10, 85. Sadhal, S. S.; Johnson, R. E. J. Fluid Mech. 1983, 126, 237. Schwartz, L. W.; Princen, H. M.; Kiss, A. D. J. Fluid Mech. 1986, 172, 259. Shen, E. I.-C. Ph.D. Thesis, University of California, Berkeley, 1984. St. Laurent, C. M.; Gauglitz, P. A.; Radke, C. J. “An Experimental Study of Snap-off in Constricted Glass Capillaries of Circular and Square Cross Section”. Undergraduate Research Report, 1986; Lawrence Berkeley Laboratory, University of California, Berkeley, LBID-1165. Strand, S. R.; Hurmence, C. J.; Davis, H. T.; Scriven, L. E.; Mohanty, K. K. “Choke-off of Non-wetting Fluids in Porous Media”. Research Report, 1982; University of Minnesota, Minneapolis.
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Received for review September 22, 1986 Accepted February 10, 1988
Synthesis of 4A Zeolite from Calcined Kaolins for Use in Detergents Enrique Costa,* Antonio de Lucas, M. Angeles Uguina, and Juan Carlos Ruiz Department of Chemical Engineering, Universidad Complutense, 28040 Madrid, Spain
The synthesis of 4A zeolite from calcined kaolins has been investigated. The process variables of the different synthesis steps have been optimized in order t o produce 4A zeolite at a lower price with the established specifications for use in detergents. The recovery of the mother liquors required for the economical viability of this process has been verified. An economical evaluation of this process has been carried out with an estimated price for the zeolite of 5 4 peseta ($0.43)/kg. The necessity to reduce the contamination of rivers and lakes caused by phosphates has led to the development of a phosphate substitute as a builder in detergents (Layman, 1984). The builder content in detergents can reach 30% by weight (Burzio and Pasetti, 1983). A suitable builder as a substitute for phosphates should meet the following requirements: no degradation of detergent qualities,
toxicologically and ecologically safe, and economically feasible with the possibility of large-scale production from easily available raw materials (Ettlinger and Ferch, 1978). The search for phosphate substitutes was initially concentrated on water-soluble inorganic substances such as soda and water glass, and organic complexing agents such as citrate and NTA and EDTA sodium salts (Berth et al.,
0888-5885/88/2627-1291$01.50/0 0 1988 American Chemical Society
1292 Ind. Eng. Chem. Res., Vol. 27, No. 7, 1988 NAmM
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Table I. Chemical and Mineralogical Compositions and Particle Sizes of Kaolins kaolin Pa kaolin E* kaolin P-3OC Chemical Composition, wt % SiO, 49.00 47.70 48.00 36.50 37.00 38.20 '41203 0.47 0.98 %O3 0.46 TiO, 0.25 0.11 MgO 0.12 0.26 CaO 0.17 0.07 0.03 K20 0.48 0.46 0.96 Na,O 0.06 0.04 0.06 12.80 13.25 1.1.50 calcination loss Si0,/ A1,0," 2.25 2.14 2.24 kaolinite mica quartz
d, > 10 Wm d, < 2 ym i
4~
Mineralogical Composition, wt % 93.0 95.0 2.0 5.0
3.0 2.0
Particle Size, wt 70 13.0 12.0 53.0
51.o
90.0 10.0
14.9 47.1
"Caosil S.A. ',Canbar S.A. 'Canlines de Vimianzo S.A. "Molar ratio.
ira ITE
Figure 1. Sequential steps and process variables for synthesis of zeolites from natural clays.
the established specifications for its use in detergent formulation.
1975). In the past decade, numerous patents have been filed by different companies which produce detergents (Burriesci et al., 1983). Among the sequestrants and ion exchangers proposed, synthetic zeolites such as types 4A and 13X constitute a valid alternative for phosphate substitution in detergents (Stack, 1983). Thus, the commercial produds HAB-40 and SASE produced by Degussa and Henkel, respectively, are a pure 4A zeolite, whose characteristics have been optimized for use in detergents (Ettlinger and Ferch, 1978; Weber, 1977; Ferris, 1977; Bosh et al., 1983). The use of zeolites as builders in detergents requires a competitive price with regard to phosphates and other possible sequestrants. For this reason, zeolites must be synthesized from economical raw materials such as natural clays, particularly kaolins. Figure 1shows the necessary sequential steps for this synthesis and the most significant process variables. These variables must be optimized for each raw clay due to their different structures and compositions (Bosh et al., 1983). The recovery of mother liquors is essential for the economical viability of this process. The principal problem of marketing zeolite from natural clays for its use in detergent formulation is that the product fulfills the established specifications: high crystallinity (X, = loo%), calcium binding (C, = 2.8 mmol/g), whiteness (Hunter index, L > 90%), and adequate particle size distribution (average diameter = 4 pm, 99 wt % in the range 1-10 pm) (Derleth et al., 1977; Endres and Drave, 1978; Ettlinger and Ferch, 1978; Gresser, 1982). Spanish clays and clay minerals reserves are very important because of their abundance, high purity, and variety. In a previous investigation, the synthesis of 4A zeolite from different Spanish clay minerals was considered. Three Spanish kaolins were selected, based on their optimum Si02/A1,0, molar ratio (==2), high purity (kaolinite >90 wt %) and easy pretreatment by calcination. The maximum concentration allowed for the impurities in the raw kaolins (CaO + MgO 10 pm is Jifferent. The zeolites obtained with the three kaolins are adequate for use in the formulation of detergents if the particles with d, > 10 Fm are removed, but the zeolite obtained from kaolin P is the best from an economical point of view. Although it needs to be ground and wet sieved, both the crystallization time and the contents of particles with d, > 10 pm are the lowest. The detersive efficacy (detersive efficacy was determined by a Spanish detergent maker, measuring the whiteness of a white standard cloth after washing) of three detergents with a standard formulation (30 wt % of builder) was tested using sodium tripolyphosphate, zeolite 4A obtained from kaolin P without removing particles with d, > 10 pm, and Sasil. It was observed that the detersive efficacy of Sasil and zeolite 4A was the same and 8% lower than that of the detergent with sodium tripolyphosphate.
Ind. Eng. Chem. Res. 1988,27, 1296-1300
1296
Finally, an economical evaluation of the process proposed in this investigation using kaolin P has been carried out for a production of 30.000 metric tonlyear. Taking into consideration a period of amortization of 10 years and an annual profit of approximately 15% of the total investment of 1700 X IO6 peseta ($14 x lo6), the resulting estimated price for the zeolite is 54 peseta ($0.43)/kg, (Ruiz, 1986). This price is comparable with other detergent builders.
Literature Cited Aranda, C. "Capacidad de intercambio ibnico de la zeolita 4 A Influencia de las condicioness de sintesis y de operacibn." Tesina de licenciatura, Universidad Complutense de Madrid, Madrid, 1982. Berth, P.; Jakobi, G.; Schmadel, E.; Schwuger, M. J.; Krauch, C. H. Angew. Chem. 1975,87, 115. Bosh, P.; Ortiz, L.; Schifter, I. Ind. Eng. Chem. Prod. Res. Deu. 1983, 22, 401. Burriesci, N.; Corigliano, F.; Saja, L.; Zipelli, C.; Bart, C. J. J. Chem. Technol. Biotechnol. 1983, 33A, 421. Burzio, F.; Pasetti, A. Rev. It. Sostanze Grasse 1983, 60, 7. Costa, E.; Sotelo, J. L.; Gutierrez, M. L.; Uguina, M. A. An. Quim. 1979, 75, 96.
Costa, E.; Lucas, A.; Uguina, M. A.; Ruiz, J. C. An. Quim. 1988, in press. Derleth, H.; Walter, L.; Bretz, K. H.; Kurs, A. Ger. Often Patent P2705088.0, 1977. Endres, R.; Drave, H. Ger. Often Patent P2852674.1., 1978. Ettlinger, M.; Ferch, H. Manuf. Chem. Aerosol News 1978,49, 51. Ferris, A. P. G.B. Patent 23049, 1977. Garside, J. Chem. Eng. Sci. 1985, 40, 3. Gresser, R. Fr. Patent APPL 82/10.368, 1982. Grove, C. S. Advances in Chemical Engeneering; Academic: New York, 1962; Vol. 3. Kostinko, J. A. Symposium of Advances in Zeolite Chemistry, Las Vegas, 1982. Layman, P. Chem. Eng. News 1984,23, 17. Rodrigo, L. C. "Sintesis de la zeolita A de sodio a partir de productos comerciales: Influencia de las variables." Tesina de licenciatura, Universidad Complutense de Madrid, Madrid, 1981. Ruiz, J. C. "Sintesis de zeolita 4A a partir de caolines." Tesis doctoral, Universidad Complutense de Madrid, Madrid, 1986. Stack, H. Eur. Chem. News 1983, 1. Schweitzer, P. Handbook of Separation Techniques f o r Chemical Engineers; McGraw-Hill: New York, 1979. Weber, H. Ger. Often Patent P 2715934.8, 1977.
Received for review J u n e 25, 1987 Revised manuscript received January 26, 1988 Accepted February 10, 1988
Water Repellent Efficacy of Wax Used in Hardboard Oscar H. H. HSU*and Howard S. Bender John M. Coates Research Center, Masonite Corporation, St. Charles, Illinois 601 74
An important property of commercial hardboard is its resistance to wetting and the penetration of water. T o accomplish a satisfactory degree of water resistance generally requires the use of a hydrophobic material called "size". Wax has been used as a water-repellent sizing agent in the hardboard industry for decades. Work was conducted to identify the mechanism of wax performance as an effective sizing compound. The chemical structure and molecular size were found to be the essential factors which determine the effectiveness of wax as a water repellent. The degree of branching and carbon chain length of the hydrocarbon affect water repellency. Furthermore, by heat treating the wax, its effectiveness can be increased. A simple technique to identify the efficacy of the wax is described.
Wood and paper products have traditionally used sizes to impart water repellency. For wood fiberboards and hardboards exposed to weather as siding and roofing products, high water repellency is essential to prevent wetting of rain into exposed faces and edges. In these products, hydrocarbon waxes derived from petroleum crude are the commonly used sizing agents. These waxes come from petroleum refining involving distillation at elevated temperatures and subatmospheric pressures to split the petroleum crude into distillates and unvolatilized residues. Some of the distillates are sufficiently high in molecular weight to yield semisolid waxes (slack waxes) when cooled to room temperature. The residue is solvent extracted to yield lube oils, waxes, and asphaltic tars. Slack waxes are a mixture of viscous oils and semisolid (paraffinic) waxes, whereas, petrolatum contains hard wax (microcrystalline waxes) mixed in semisolid paraffinic wax and viscous oils. Wide variations in color, hardness, melting point, melt viscosity, and water repellency have been observed by hardboard makers using these different waxes. Because of the criticality of water repellency to weatherability, we undertook a study to ascertain those attributes of hydrocarbon waxes that affect water repellency. The results of the investigation are described in this paper and involved 0888-588518812621-1296$0l.50/0
studies of the materials in bulk and at the molecular level. Roffael and May (1983) have discussed the influence of chain length, chain length distribution, and paraffinicity on the sizing behavior of paraffins in particleboard. We have extended our program beyond this point; molecular weight, molecular weight distribution, viscosity, melting point, oil content, and degree of branching are discussed. As a result of this work, a practical method for measuring water-repellent efficacy is introduced. Materials used in hardboard manufacture, in addition to wood, include substances which influence either the physical or mechanical properties of the final product. Sizing compounds are normally used to affect the interaction between water and wood, in particular, the cellulose and hemicellulose fraction. Products derived from wood through their reduction to fiber and subsequent processing to hardboard, paper, and similar materials retain this interaction with water. The interaction between the wood components and water causes profound dimensional and strength changes. A variety of materials have been employed by various manufacturers of hardboard to achieve water repellency. Consequently, a number of hardboard manufacturers have used various substances to impart water repellency to their product. These include petrolatum wax, tall oil pitch, fatty acids and their derivatives, 0 1988 American Chemical Society
