This paper proposes a method of analysis for problems of complex heat transfer in high-temperature furnaces, based upon the idea of thermal resistances in series and in parallel, and gives formulae for calculating the chief items of thermal resistances in a rotary kiln. It is proposed to use △(Tn) as the driving force in radiant heat-transfer. In a full discussion of periodic heat-flow into and from a refractory lining, it is pointed out that the "Thermal impedance" applicable to average values of temperature and heat flow is different from the ordinary a.c. impedance (applicable to r.m.s. values), and an approximate formula based upon rational analysis is given. The simplified mechanism of heat transfer between granules of calcinated material is also discussed.

In this paper the influence of Pr number, shape and thermal conductivity of the packing material and the bed height on the heat transfer coefficients of the packed beds have been thoroughly studied when air and water were cooled through packed tubes. In order to offer the data for the design of fixed bed, catalytic reactors and packed heat exchangers operated at high space velocity, high Re number was adopted. In case of spherical packings of low thermal conductivity, such as glass, ceramics, the heat transfer coefficient may be correlated as follows: experimental ranges: Dp/Dt = 0.08~0.5; L/Dt = 10~30; Re = 250~6500; Pr= 0.722~4.8. In case of shperical packings of high thermal conductivity such as copper, iron, the heat transfer coefficient may be correlated as follows:Nu = 2.17 Re0.52 . experimental ranges: Dp/Dt = 0.1~0.5; Re = 300~10;000; L/Dt = 10~30. Within above ranges, all experiments were repeated at least twice, the error was not greater than 5%. For the cylindrical packings, the particle diameter in the Re number of the above equations should be changed into the equivalent diameter of a sphere which has the same surface area as the cylinder.

The completely unmixing of the liquid on the plates was assumed by Lewis to derive the theoretical relation between the plate efficiency and local efficiency. This assumption is not true for the actual cases. In the present paper, introducing a conception of the liquid pool, suggested early by Kirschbaum, to express the mixibility of the liquid on the plates. Using this conception the three equations were derived for three cases as in the Lewiss paper. It is interested to note that the first two cases, as k approaches infinity, can be reduced to the Lewiss form, and as k=l, equal to the Murphrees plate efficiency. These derived equations are the intermediate between the Lewis and Murphree equation, which represent the extremes of actual condition. In this paper, a method for estimating the point efficiency is also given, which is resonablly shown by the two examples. However, no further experimental data are available to demonstrate the utility.

Minute amount of sulfur dioxide and impurities are always present in the air of industrial area. Under sunlight, smog is formed, scattering light and reducing visibility. This article is to ascertain the effect of rate of photochemical oxidation of sulfur dioxide in air at high relative humidities. During experiment, pure air from a special kind of filter was mixed with sulfur dioxide and stored in a Lucite reactor (7.94 liters), with RS sunlamp shining successively through an infra-red filter and Plexiglas IA on the top of the reactor for 1 to 2 hours. The size of sulfuric acid aerosol particles thus formed was in logarithmic-probability distribution. The particles were impacted at high velocity upon the photographic film which was impregnated with thymol blue indicator after having had its silver salts removed. The amount of sulfuric acid formed during the reaction was determined from measuring the intensity of light passing through the red spot on the film. The experimental results showed that at high relative humidities, the reaction rates were essentially the same as those at low humidities. This indicated that the reaction was chiefly gas-phase, with relatively very small amount of reaction in the liquid phase. Nitrogen dioxide, sodium chloride nuclei and vanadium pentoxide, the impurities usually present in the air of industrial area, showed no effect toward reaction rate. About 300 hours of intense sunlight would be needed to reduce visibility to 1 kilometer by oxidation of the sulfur dioxide to be expected in naturally occurring polluted atmosphere,

Kinetics of the oxidation of sulfur dioxide on Vanadium catalyst used in the sulfuric acid contact process is complicated not only by diffusional processes but also by the change occurring in the catalyst itself. Kinetic studies have been carried out in flow reactors at different temperatures with catalyst granules of different sizes. The effects of mass transfer have been observed. With catalyst size as ordinarily used in industry (5 mm), the reaction rate is much retarded by diffusional processes and is controlled kinetically by outer diffusion when temperature is higher than 500℃. Different rate equations are obtained with different granular sizes of the catalyst. There exists a range of temperature in which the activity of the catalyst changes according to the operating conditions. Direct observation of the catalyst in operation shows that the catalyst is bluish-green in color at 400℃ and becomes yellowish at 500℃. At 450℃ about half of the catalyst bed from the gas inlet end is bluish-green in color and the other half toward the gas exit end yellowish. The proportion of these two colored parts changes with the operating conditions. A lower activity corresponds to more of the catalyst in bluish-green color and a higher activity to more of the catalyst in yellowish. The rate equation obtained changes in form as the catalyst changes in color (the influence of rate of mass transfer not involved). For the foreward reaction at 400℃,For the reverse reaction at 550℃, Below 475℃ the activation energy is 50 Kcal/mol, but above 475℃ it becomes 24 Kcal/mol. The reduction of activation energy is due to change of the catalyst itself but not to the effect of diffusional processes. Examination of the rate equations according to the theory of indicates that the rate determining step is the reaction in the absorbed layer.

The behavier of a prehydrolysis caustic bagasse pulp in the viscose process was studied in comparison with a spruce sufite pulp. The degree of swelling in different concentrations of alkali solutions, the changes of carboxyl and aldehyde group contents and viscosity of the regenerated cellulose under various ageing conditions of alkali cellulose, the changes of solubility and degree of esterification of xanthate with different amounts of CS2 used during xanthation and the spinning with viscose method were compared. It was found that both pulps had a maximum degree of swelling in alkli solution at a concentration of 10-11 % NaOH. At the same concentration, the degree of swelling of bagasse pulp was greater than that of spruce pulp. With the increase of ageing temperature and time the carboxyl group content of cellucose increased, the viscosity decreased, but no much change in the aldehyde group content was observed. At the same condition of ageing, the oxidation and degradation of bagasse cellulose was faster. No much difference between the two pulps was found in the changes of solubility and degree of esterification of xanthate at xanthation with various amounts of CS2. The tensile strength of viscose filament from bagasse was 2.23 g/d (dry), 1.68 g/d (wet). This experiment confirmed the applicability of bagasse for the preparation of staple fiber.