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More TECHNICAL BRIEFS. exciter in the Holtwood *101100. The lotol power required is SO lew.; or 1.7S vote* per squore inch of screen bar area; of 7.5% of (he power generated by (he unit; or the equivalent of 0 4% reduction in a lota) head ol 60 feet. The heating it applied only when the temperature record* Indicate 0 postible ice run. The velocity at intake entrance ii 2.0 f(./sec. AIEE Paper No. 53-3. Coal Gasification Pulverlied Cool Combustion In o Water. Cooled Radiant Tube. By R A Sherman, C E Keinath, Battelle Memorial Insti tute ; R T Sawyer, American Locomo tive Co, Steam generators fired with pulver ized coal are now designed for rates of heal liberation of th'a order of 20.000 Biu per hour per cufl^ foot of furnace volume or leu. On the assumption of a 20 per cent excess air, of an average gas temperature in the furnace of 2500 F, and of a uniform gas flow over the entire cross-section of the furnace, the residence time of a particle in the fur nace would be 2ft seconds. Because the gas does not flow uniformly through the entire crosa-seotion, the velocity of travel is higher and the residence lime is leu than would be calculated. Inas much, however, as the residence time required for 99 per cent completeness ol combustion ol most high-volatile bi tuminous coals In the order of onequarter of d second, it is obvious that large combustion chambers ere not necessary to insure economically com plete combustion. The large volume, practically always surrounded by heat-absorbing surface. Is provided to Insure that the ash Is cooled to a temperature low enough to ovoid slagging and fouling of the boiler tubes. Such designs are highly satisfac tory from the viewpoints both of ef ficiency of combustion and freedom from excessive slagging, particularly for large steam generators where space Is not a particular premium. Where, however, space It at a pre mium as, for example, on a locomotive, pulverized coal has not been success fully fpplied. All attempts of the early 1920'a to apply pulverised coal to the team locomotive encountered difficulty because of slagged oah In the firebox and on the flue sheet of the boiler. Some years ago, under the sponsor ship of Bituminous Coal Research, Inc, it was demonstrated that pulverised coal could be successfully burned' without difficulty from slagging of ash at heat release rates of 400,000 Btu per cubic foot per hour. This was accomplished by firing the coal into a long tube of small diameter, which provided a large area of heat-absorbing surface per unit volume. The tubes used were alloy steel ol S-lneh diameter and 10-foot length. The tubes, heated to 1700 F, were the healing elements in an experi mental metallurgical annealing fumaoe. Such tubes, fired with natural gas or oil, are widely used for the heat-treat ment of metals where it is important that the combustion products must not come into contact with the work. So it was a natural step to try H on cool. This paper describes a series of com bustion trials of pulverised coal in alloysteel tubes from which the heal was absorbed by an outer, annularly spaced, water-cooled tube. Only one diameter of alloy tube, 5 in., in lengths of 10, IS and 20 ft, wos used for the trials. A highly volatile coal, pulverized to a fine ness of 90 per cent through a 200 mesh screen, was fired into this tube at rates of 40 to 160 lb. per hr. For the arrangement used, the frac tion of the coal heat input absorbed by the water in (he outer tube was only 20 to 40 per cent. Thus the particular ar rangement used wos not practical for a boiler. The interest in the tests lies in the feet that a coal whose -ash softening and fluid temperatures were 2160 and 2220 F respectively, was burned at ex tremely high heat liberation rates with out difficulty from slagging. It appears possible that 0 tube of somewhat larger diameter would give a wall temperature high enough to have s satisfactorily low loss in unbumed TO OBTAIN COMPLETE TEXT Material for these abstracts comes from the fallowing sources unless otheruns* stated. Order complete paper from source net Powxn. American Society of Mechani cal Engineers, annual meeting, Staffer Hotel, New York, N. Y. Nov 30-Dec 5, 1952. Identified by initials A$ME and obtainable through ASMS, 29 V 39th St, New York 18, N. Y. American Institute of Electrical Engineers, winter general meet ing, Staffer Hotel, New York, N. Y. Jan 19-23. J953. Identified by initials AIEE end obtainable through AlEE, 33 IP 39th St, New York 18, N. Y. carbon yet not 00 high as to difficulty from slag formal]*, . `bilily of application of Uj, Bf<3 to the steam locomotive boi|et PJ the research described, a dtu* locomotive incorporating thesehSa presented in the paper. JCtiSm No. S2-A-I23. Pulvorizad-Cool OoslficQt]i.. Troencfener, Ruhrgas aL tchaft. After briefly reviewing the ^ of Cermsny's gas demand sod * which makes U highly deslnbl f free larger omonnts of eokso* J by firing coke ovens with prodoc. the general program of resesie development of the Rtihrgn explained. Moin efforts were directed tofj the development of two gas using low-grade pulverized coal dust obtained from the wsUl. operations. The first process, invefi gasification of pulverized coil la A lex-type system, with slagged uhE moval, has reached the state of con cial applicability, and the resnlu tained exceed those ol eonvenile^^ producers gasifying coke. -j The second process described b q detail, the coal dust pulso-jet | is in the experimental stage but sin has shown promising results. Far work is in progress to improve apt (ions and efficiencies. 1 So far only producer-gas tests aiB air blast hove been mentioned. Hg ever, the same principles can be a In making synthesis gas or water fii operating with oxygen-steam blast, * the results would be expected to bs.|> ter because of the Increase in coaq (ration of the reactants. Tests with gen-steam blast are scheduled sssooo'| the ptoducer-ftM program *99TM completion. Other proeesses are 1^ under consideration at Ruhrgas *51 some are in or past the pilot-plant si including the high-pressure gssifif of bituminous eoat. The problem of producing !* fuels and synthesis gas for a number*^ Important industrial products iud H ammonia, liquid fuel, rubber, cels, etc, using coal os a basic mstenJJ is of great interest throughout the wWtl Not only do many countries have w*j quite supply of this raw material deposits are mostly of such a that sufficient supply is ensured JJI other sources moy be greatly depK*^jj| XSMrPapsr No- S2-A-102. (Continued on page 222) d|rte '''''' rfgntgirs for eliminating the impurities from boiler feed make-up rcgrigihtliy developed for large power generating stations. Eowmr, the results obtained with C-R Type R Horixomsl and yH Vertical Dentube Evaporators in industrial plants alt over Sentry hsve proved that moderate size planit con also fre- profit by the manybenefits of distilling the raw water suppiy. IHDus is a possibility well worth your investigation. Boiler feed BjMrion by G-R Evaporators does not involve the use of chemiKyypor require periodical water tests or manipulation by skilled Moreover, it is the simplest method of eliminating raw impuritieswrJy*116 ?or complete information. GR1SCOM - RUSSELL CO. MASSILLON. OHIO G-R Type R end Type H Evap orators are adaptations of the larger TypeJ-2 Bomube Evap- ' orator--widely used by cen tral power generating stations. They embody the exclusive scale-shedding G-R Bemube heating elements, and have many additional distinctive G-R features that assure ample capacity, pure dry vapor, Jong service, low maintenance ex pense and convenient attend- Bentube Evaporators 1 READER SERVICE SECTION 2; march issi