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surface arrangement to reduce deposi tion of chemical solids end facilitate removal of solids that are deposited. Mechanical soot blowing can bo ap plied successfully to clean the entire unit, eliminating crews for hand lanc ing. Parallel flow of air and gas Instead of counterflow eliminates forma tion of hard chemical deposits in air heater. Paper also presents economic factors influencing steam production and bow they enter into over-aU design of unit. ASMS Paper No. 48-S-2. Mechanisms of Combustion and Their Relation to OU.Burner Design, by H R Heiple and IP A Sullivan* Shell OU Co, lac. Combustion of fuels generally occurs in the vapor phase. To under stand the combustion process the au thors take up first a study of the kinetics of gaseous reactions. Rste of reaction depends on temper ature because collisions occur more often (proportional to the square root of the absolute temperature) and the percentage of molecules, possessing ex cess energy above the minimum needed, increases. Activation energy is ex pressed by e**'"r, where E and R are constants; T la absolute temperature. Chemical reactions occur by one cf ' two mechanisms, namely, thermal or chain. Thermal reactions involve mole cular species only. Reactant molecules dissipate excess energy liberated. by the reaction nonapecifically. Fre quently this dissipation raises the tem perature of the reacting mass, acceler ates the reaction. If the initial temper ature is above a certain value, reaction accelerates until the rate becomea in finitely large. A thermal explosion results. Chain mechanism, the second path for reactions, hat the initial reaction followed by a chain of successive ontes. Sometimes resultant molecules transfer excess energy to one or another of the reactant molecules. This gives rise to s series of reactions. The reaction is described as an energy-chain one. Other chain reactions Include as re actants atoms and radicals (metastable molecular species.) The over-aU rate of reaction is proportional to concen tration of chain carriers. The rate of formation or destruction of these car riers is most important. Whb this background the authors study oxidation of hydrocarbons and in turn their properties as they affect burner design. Next, they discuss ma jor burner types! how they fit theory developed. ASME Paper No. 47-A-34. the base-load unit is definitely superior, To Obtain Complete Text Material In these briefs comes from one of two sources; American Soe of Mechanical En gineers, annual meeting, Atlantic City. N. U Dee. 1-5, 1947. Papers Identified by initials ASME and paper No. preeeded by 4T-A. to that of peak load. Tests of 4000-kw standby unit foti Chimboto, Peru (PowEn,- Apr 1947, p. 228-9) again show better than gusi-'y anteed performance and .indicate id. r. vancea. made aince design of similar Neuchatel unit. Paper also describes other current American Soe of Mechanleal En gineers, spring meeting. New Or leans, La, March 1-4, 1948. Papers identified by Initials ASMS and paper No. procoded by 48-S. Available while supply lasts at American Soc. of Mechanical En gineers, 29 IP JWi St, Now York. designs: (1) Two 4000-kw units (or Southern Iren, using natural gas fuel, employ s slnglo-stago Impulse^ turbine for starting. Expansion of gu,< from well pressure of about 400-pai to' 60-psi pressure of the combustion cham ber, drives this turbine, which provider UJadditional net power after starting accomplished. (2) Sets of 13,000 andj Synthetic Liquid Foals In the United States, by IP C Schroedcr, U. S. Bureau of Minei. The disappearance of reserve copacity to produce natural crude oil in the U. S. U the most important differ ence between the country's prewar and postwar economic and security situa tion. Since the passage of the Synthetic Liquid Fuels Act in 1944 it has become increasingly apparent that the U. S. will turn to synthetic sources to augment its petroleum resources. Anticipated costs 27,000 kw (largest yet built) under; construction for Beznau Station Switzerland, where they will serve lo! back up hydro system in water-short] winter months. Low Inlet-air tempers; tures then prevailing give considerable! added capacity; 13,000-kw unit is saini as 10,000-kw design for normal sir! inlet temperature, 27,000-kw machlnt Is essentially the same os a 10,000-kvj design doubled. Paper concludes with reasoning hind adherence to relatively concern] Uve throttle temperatures in light at the plant for products produced from, first, natural gas and, later, oil shale and eoal, will run from.3 to Sc a gallon lack of long-time data on hlgh-lempersture alloys. ASME Paper No. 4B-S-7. higher than the present prices. ASME Paper No. 47-A-40. The Goa Tnrbine as a Stationary Prli Mover, by L N Rowley and B G SkrotM, Powcn, McGraw-Hill Publish BAS TURBINES Performance of Commercial Gas Tarbines, by Paul R Sidler, Broun Boveri ing Co. Because fuel cost and plant investment Tory widely from place place and lime to time, comparison o[ gas turbines with steom and d!ox]| plants is presented with these elemenf Corp. After reviewing experience with original 4000-kw standby installation at Neuchatel, Switxerlond, and with 2200bp locomotive unit of Swiss Federal as variables. Curves show, for any gives] fuel cost and plant Investment, the lastifiable investment in the competing font) of plant These comparisons, for as! Railways, paper describes and gives performance of severat larger units tested and shipped in last year or so. isolated plant of 10,000 kw, are sup* plemented by an economic evaluation of gas turbines and steam plants, W! Tests of 10,000-kw standby unit for both base and peak loads, as an tddn Fllxret Station, Rumania, show: (1) tion to an existing system. This csw] overload capacity to 12,000 kw at 68-F study shows marked influence of tl air-inlet temperature (2) ability to efficiency level of the existing systefll reach full speed about S minutes after starting motors are switched in, or 4 to 4.5 minutes after combustion chambers are Ignited (3) ability to take full load as fast as load .can be applied after on the results. The gas turbine as W booster at the end of a transmission Us*j is also evaluated. - To adapt the gas turbine to Industrie!; power applications, provision (or obv speed has been reached, and (4) shutting-down time no longer than for steam turbines. Tests of generally similar unit for base-load service at talning process heat is often naeesssflj. Various possible modifications of d*. gas-turbine cycle to effect heat recover?! are illustrated. Diagrams show potf, Lima, Peru, show guarantee of 28% sibilitics of heat recovery at high over-all thermal efficiency ..met by com perature as well as at exhaust-temp*^ fortable margin. Pert-load efficiency for ture level. ASME Paper No. 48-S-S- 1)4 (441) POWER July H.4*