CENTRIFUGATION James 0. Msloney,
0 QUANTITATIVE information on the effect of the major variables influencing centrifugal operation has appeared in the literature during the year. Although the qualitative effects are fairly well known, chemical engineers still need a considerable amount of data in order to make a preliminary selection of equipment. GENERALAPPLICATIONSOF EQUIPMENT. Two papers appeared during the past year, describing in some detail the fields of application of certain types of centrifuges. Bryden (5) points out that new developments resulting in improved lubricating oils have, in turn, required that equipment be better protected from dust and water in the oils. Now improved turbine oils in which the oxidation rate has been greatly reduced require a minimum of water washing under normal conditions to remove oxidation products. Water washing, however, has been found desirable if the oil is in an atmosphere of corrosive vapors which condense in the oil and attack the metal parts in contact with the oil. It haa been found that many oxidation-inhibited oils are more easily purified centrifugally than are the straight mineral oils. Bryden states that operators of turbine equipment are using their centrifugal purifiers continuously in order to decrease maintenance costs on the turbine. Filtration of the oil through certain types of activated earth has been found to remove both oxidation and rust inhibitors. The desire for a visibly clean Diesel lubricating oil has resulted in the combination of a paper disk filter and an oil-water separating centrifuge. Bryden reports that the centrifuge needs cleaning only about one third as often and that the filter does not plug up with water. A centrifuge separating wax continuously from crude oil, used as a fuel for Diesel engines, has improved the operation of Diesel engines pumping crude oil. Jacobs el al. (11)describe pilot plant comparisons of a Shriver filter, an Oliver precoat filter, a Bird solid bowl centrifuge, and a Lurgi band filter for the separation of solids from a manganese sulfate solution. Essentially complete operating data on. all of these units are presented. Because of limitations in the performance of all except the Shriver filter, an economic analysis was not required. Experiments on the extraction of tannins are reported by Beebe et al. (4). It was observed that if the pieces of tannincontaining material were too large, it was difficult to extra& the tannin. On the other hand, when the material was ground too h e , it either could not be wet thoroughly or it packed into a solid. By grinding the material or crushing it, mixing it with water and grinding, and finally centrifuging the entire mixture in a basket-type centrifuge, the recovery of tannins was good. There is an increasing use of high speed centrifuges in the biological sciences. Ogston (17, 18, 19) employed an air-driven centrifugal operating a t two speeds-24,000 and 40,000 revolutions per minute-to separate tobacco mosaic virus. Chargaff (6) studied the distribution of thromboplastic activity in representative cellular fractions of beef lungs. The fractions were obtained by centrifugation at 1900 times gravity, followed by centrifugation at 31,000 times gravity. All of the activity was found to be confined to the sediment from the 31,000 X gravity operation. Stanley (22) and Taylor et al. (25) employed the high speed centrifuge in the sedimentation of influenza virus and vaccinee. Taylor (23, 24) also employed a Sharples mpercentrifuge for preliminary concentration of rabbit papilloma. This was followed by further concentration in an ultracentrifuge to
UNIVERSITY OFKANSAS,LAWRENCE, KANS.
produce this virus in satisfactory purity and yield. An unsuccessful attempt was made by Baker el al. (I, 8) to determine the distribution of water in bread doughs with a Sharples centrifuge. Mitham and Yardley (16) describe in considerable detail a dynamic brake for a laboratory high speed centrifuge. Dynamical braking is a method of stopping or slowing down moving equipment in which the stored mechanical energy of the body is converted into electricity and the electricity reconverted into work in an external circuit. The rate at which this energy is removed determines the time required to bring unit to rest. This method of stopping rapidly moving mechanisms saves wear and tear. A clever process for continuously obtaining the specific gravity of a gas by means of centrifugal force was devised by Dowling (7). It is based on the principle that, if a tube filled with gas is revolved about one end, a pressure difference proportional to t h e average density of the gas develops. By having two tubes, one containing a standard gas and the other the gas whose gravity is to be determined, it is possible to measure the pressure differencea and determine the gravity of the unknown gas. Irving (10) describes the ter Meer continuous centrifugal and points out that it is limited to the separation of relatively coarse, free-draining solids from a liquid. The considerations in the design of the discharge mechanism are reported in considerable detail. FUNDAMENTAL DEVELOPMENTS.Bryden (6) lists a number of important considerations in the design of centrifugal purifier bowls. Included in this list are: efficiency of separation, stability of operation with varying feed composition, feed distribution and flow, mechanical stability, and ease of cleaning. PATENTS.A number of patents have appeared during the year on centrifugal separations (3, 8, 9, 18-f6,go, 81, 86). Lindgren and Thylefors (15) patented a device for discharging sludge from the periphery of the bowl. I n Schutte's centrifugal filter for removing wax @I),a temperature gradient exists from the top to the bottom of the unit. A method for refining crude waxes in a centrifuge waa patented by Gilmore (8). Lars (IS) designed a vertical, pear-shaped, centrifugal separator bowl containing a number of flat disk-shaped separator elements, in each of which a hole is drilled. Jones (18) patented a unit for separating three phases by first separating the mixture into a light and heavy phase, the heavy phase containing essentially all of the intermediate phase. Hertrich (9) describes a device for driving centrifugal equipment employing a turbine.
N
LITERATURE CITED
(1) Baker, J. C., Parker, H. K., and Mise, M. D., Cereal Chem., 23,, 16-30 (1946). (2)Ibid., 23, 30-8 (1946). (3) Bath, W. H.,U. 8. Patent 2,350,014(July 10, 1945). (4) Beebe, C.W.,Cordon, T. C., and Rogers, J. S., J. Am. Leather Chem. Assoc., 41, 161-71 (1946). (5) Bryden, C . W.,Natl. Conf. on Petroleum, Am. SOC.Mech. Engrs., Tulsa, Okla., Oct. 7,1946. ( 8 ) Chargaff, E., J. B i d . Chem., 160,351-9 (1945). (7) Dowling, J. J., J. Sci. Instruments, 22,No.5,145-8 (1946). (8) Gilmore, F. H., Australian Patent 118,047 (Feb. 3,1944). (9) Hertrich, J., U.S. Patent 2,402,496(June 18, 1946). (10) Irving, H.F.,Mech. Eng., 68, 330-2 (1946). (11) Jacobs, J. H.,Hunter, J. W., Yarroll, W. H., Churchward, P. E., and Knickerbocker, R. G., U. S. Bur. Mines, Bull. 463. (1946).
(Continued on page 36) 1,6
January 1947 (46) (47) (48) (49) (50) (51) (52) (53) (54) (55) (56) (57) (58) (59) (60) (61) (62) (63) (64) (65) (66) (67) (68) (69) (70) (71) (72) (73) (74) (75) (76) (77) (78)
INDUSTRIAL AND ENGINEERING CHEMISTRY
Reinemann, H., Krieger, K. A., and McCarter, W. S. W., IND.ENG.CKEM.,38,839 (1946). Helbig, W. A., in Alexander’s “Colloid Chemistry”, Vol. 6, Chap. 36 and Appendix 2, New York, Reinhold Pub. Cow., 1946. Hinners, H. F-9 McCarthY, J. J., and Bass, R. E., oil & Soap, 33, 22 (1946). Hookley, R. L., Chem. Eng. News, 21, 2132 (1943). Hollings, H., and Hay, S., Chemistry & Industry, Feb. 16, 1934, 143. Hormatz, s., Chem. & Met. Eng., June, 1946, 112. Howard, F., and Sporrer, E. C. R., Chemistry & Industry, May 11, 1946, 186. Jones, G. C., Natl. Petroleum News, 34, No. 7, R57 (1942). Kiesskalt, S., U. 8 . Patents 2,349,098 and 2,354,383 (1944). King, H. L., Jr., Laughlin, C. D., and Gwyn, H. M., Jr., Oil Gas J., 42, No. 49, Sec. 1, 236; No. 50, 71 (1944). Koch, J. M., IND.ENG.CHEM.,ANAL.ED., 16, 25 (1944). Kuhn, A,, and Gerhard, H., Kolloid-Z., 103, 130 (1943). La Lande, W. A., Jr., IND. ENG.CHEM.,33, 108 (1941). La Lande, W. A,, Jr., McCarter, W. S,W., and Sanborn, J. B., Ibid., 36, 99 (1944). La Lande, W. A., Jr., Sanborn, J. B., Aepli, 0. T., and McCarter, W. S. W., Ibid., 34, 988 (1942). Langston, R. B., and Rich, A. D., Oil & Soap, 33, No. 6, 182 (1946). IAeeming, Jos., “Modern Ship Storage”, P. 193, Washington, U. 8. Govt. Printing Office, 1942. TdePaget G. and KamPbek E., J. B i d Chem., 162, 163 (1946). Levin, H., Uhrig, K., and Roberts, F. M., IND.ENO.CHEM., ANAL.ED., 17, 212 (1945). Lew, B. W., Wolfram, M. L.,and Goepp, R. M., Jr., J. Am. Chem. Soc., 68, 1449 (1946). Logan, L. A,, U. 9. Patents 2,111,218 (1938); 2,174,666 and 2,180,712 (1939). Lohmann, B., Oel u. Kohle, 40, 183 (1944). Love, F. H., Petroleum Engr., 17, No. 5 , 151 (1946). hates, E. L., in Alexander’s “Colloid Chemistry”, Chap. 6, p. 840 (1946). McBride, R. S., Chem. & Met. Eng., 42, No. 10, 532 (1935). MacDonald, J. C., Intern. Sugar J.,46, 294, 318 (1944). Mackert, Anton, U. 8. Patent 1,866,417 (1928). Mair, B. J., and Forziata, A. F., J. Research Natl. Bur. Standards, 32, 151, 165 (1944); 34, 435 (1945). Mantell, C. L., “Adsorption”, New York, McGraw-Hill Book Co., 1945. Moffett, T. F. J., Heating & Ventilating, April, 1943, 33. Morgan, J. J., and Fink, C. E., IND.ENO.CHEM., 38, 219 (1946). Mueller, M. F., Chem. Eng. News, 23, 1628 (1945). Munkelt, F. H., A i r Conditioning & Rejrig. News, June 10, 17. and 24, 1946. Munkelt, F. H., Refrig. Eng., 47, 21 (1944). Munkelt, F. H., By.Age, 121, 97 (1946). Naval Med. Research Inst., Natl. Naval Med. Center, Bethesda, Md., Report, June 25, 1946. Nebeck, H. J., U. S. Patent 2,329,930 (1943). Othmer, D. F., and Sawyer, F. G., IND.ENG. CHEM.,35, 1269 (1943). Papps, George, and Othmer, D. F., Ibid., 36, 430 (1944). Parker, R. W., Petroleum Engr., 14, No. 4, 110 (1943). Porter, R. W., Chem. Eng., 53, No. 4, 94 (1946). ftamat, A., Chimie & industrie, 52, 64 (1944). Hay, A. B., U. S. Patent 2,055,774 (1936). Ray, A. B., and Logan, L. A., Ibid., 2,211,162 (1940). Regna, P. P., Trans. Am. Inst. Chem. Engrs., 40, 759 (1944). Ryan, J. F., U. S. Patent 2,402,779 (1946). Sanders, M. T., IND.ENG.CHEM.,20, 791 (1928). Sawyer, F. G., and Othmer, D. F., Ibid., 36, 894 (1944). Schindel, E., Chem. App., 27, 257, 273 (1940). Seddon, H. J., and Florey, H. W., Lancet, 1942, 6200. Sierp, F., Gas- u. Wasserjach, 76, 105 (1933). Sigworth, E. A,, J. Am. Water Works Assoc., 35, 1587 (1943). Simpson, G. L., Chem. & Met. Eng., 47, 310 (1940). Bimpson, T. P., Nicholls, E. S., and Payne, J. W., Trans. Am. Inst. Chem. Engrs., 36, 841 (1940). Bkerrett, R. G., Compressed A i r Mag., 50, 280 (1945). Sleik, Henry, Modern Power and Eng., 40, 59 (1946). Smock, R. M., and Southwick, F. W., Cornel1 Univ., Publication of Dept. of Pomology, 1946. Btanisavlievici, L., Gas- u. Wasserfach., 85, 353 (1942). Y’elephony, “Signal Corps Cable Splicing”, Deo. 11, 1943. Thau, A., Oel u. Kohle, 40, 208 (1944). Xolbert, N. E., and Amerine, M. A,, IND.ENQ.CHBM.,35, 1078 (1943).
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(107) Urdahl, T. H., and Queer, E. R., Heating, Piping Air Conditioning, 71 (March 1946). (108) Wachtel, J. L., U. S. Patent 2,399,840 (1946). (109) Wade, H. W., Petroleum Eng., 14, 100, 184 (1943). (110) Waeser, B., 2. kompr. fliiss. Gase, 38, 1 (1943). (111) Walker, R., Applebee, H. C., and Howell, A. K., Gas J., March 8, 1944, 310. (112) Wilkinson, H. H., Chem. Eng. News, 21, No. 13, 1054 (1943). (113) Williams, G. C., and Fallin, E. A., IND. ENG.CHEM.,35, 241 (1943). (114) Ziel, H. E., and Sleik, Henry, Heating, Piping A i r Conditioning, 15, No. 7, 367 (1943).
CENTRIFUGATION CONTINUED FROM PAQPI 16
(12) Jones, L. D., U. 8. Patent 2,407,834 (Sept. 17, 1946). (13) Lars, E., Ibid., 2,403,089 (July 2, 1946). (14) Lindgren, H. O., Swedish Patent 100,822 (Feb. 4, 1941). (16) Lindgren, H. O., and Thylefors, H., U. S. Patent 2,378,778 (June 19, 1945). (16) Mitham, D. J., and Yardley, V. A., Chemistry & Induatry, 1945, 307-8. (17) Ogston, A. G., Brit. J. Erptl. Path., 26, 286-7 (1945). (18) Ibid., 26, 294-312 (1945). (19) Ibid., 26, 313-15 (1945). (20) Schneible, C. B., and Herman, C. C., U. S. Patent 2,374,238 (April 24,1945). (21) Schutte, A. A., Ibid., 2,379,993 (July 10, 1945). (22) Stanley, W. M., J. Ezptl. Med., 79, 255 (1944). (23) Taylor, A. R., J. Bioi. Chem., 163, 283-7 (1946). (24) Ibid,, 163, 289-99 (1946). (25) Taylor, A. R., Sharp, D. G . , McLean, I. W., Jr., Beard, D., and Beard, J. W., J.Immunol., 50, 291 (1945). (26) Tholl, J. F., U. S. Patent 2,384,784, (Sept. 11, 1945).
HEAT TRANSFER C O N T I N U l D FROM
PAQl29
aircraft wings, Tribus (63) illustrated four exchangers designed primarily for lightness in weight; and with respect to refrigeration equipment Swart (69) described the capillary heat exchanger, which, by virtue of an intentional extremely high pressure drop, is used to replace the expansion valve normally used in vapor compression refrigeration systems. Contributions to the patent literature were made by Sewell (64) for a heat exchanger fin, Ryder (49) for a support for finned tubes, and Stewart (67) for temperature control for heat exchange units. The pebble heater was described by Norton (38)as a new heat transfer unit for industry used for extremely high temperatures. Heat is transferred from combustion gases to a descending body of pebbles which then enter a chamber through a lock feeder; there they give up the absorbed heat to the desired stream. The cooled pebbles are then elevated so they can enter the first chamber through another lock feeder to continue the cycle. Application of air cooling to petroleum refining, of advantage where cooling water is not readily available, was described by Demarest (IO). A tabulation of recently announced heat transfer equipment was compiled in connection with a review article (6) on process equipment developments. The art of exchanger cleaning was discussed by Feller and Williams (I3) in connection with chemical cleaning, and by Williams (6‘7),who described portable pumping equipment for chemical cleaning. Water lancing, which is used to reduce superheater fouling by alternate heating and chilling of bonded deposits, wae
