Rotating boiler

P. J. Marto and V. H. Gray, Effects of High Accelerations and Heat Fluxes on Nucleate Boiling of Water in an Axisymmetric Rotating Boiler, NASA TN D-6307, NASA, Cleveland, OH, 1971. 

The historical aspects of heat and mass transfer enhancement, or intensification, are of interest for many reasons. We can examine some processes that were intensified some decades before the phrase process intensification became common in the process engineering (particularly chemical) literature. Some used electric fields, others employed centrifugal forces. The use of rotation to intensily heat and mass transfer has, as we wiU see, become one of the most spectacular tools in the armoury of the plant engineer in several unit operations, ranging from reactors to separators. However, it was in the area of heat transfer - in particular two-phase operation - that rotation was first exploited in industrial plants. The rotating boiler is an interesting starting point, and rotation forms the essence of PI within this chapter. 

Figure 1.3 Schematic diagram of the experimentai NASA rotating boiler.

An application of a rotating boiler, and all other components in the rotating heat pipe described above, is in a rotating air conditioning unit. Illustrated in Figure 1.5, the... 

Anon, (1946). Vorkanf rotating boiler (Drehkessel) and rotating boiler gas turbine (Drehkessel Turbine). British inteUigenee objectives sub-committee final report No. 931, item no. 29, London, HMSO. 

Gray, V.H., Marto, PJ. and Joslyn, A.W. (1968). Boiling heat transfer coefficients, interface behaviour, and vapour quality in rotating boilers operating to 475 Gs. NASA TN D-4136, March. 

The core (almond, nut, sugar crystal etc.) is moistened with a sugar solution in a rotating boiler and then covered with a layer of sugar by the subsequent addition of powdered sugar. This process is repeated until the desired layer thickness is attained. Chocolate, if necessary, is applied in a corresponding manner. 

Smooth starts are possible with steam turbine installations that include an auxiliary boiler because the startup phases of the turbocompressor can be matched to different plant operating conditions. Aside from process-related timing issues, the time elapse or machinery startup duration is generally determined by the temperature gradients admissible on both steam turbine and expander. These factors are influenced by the relative expansion rates of the fixed and rotating components in these machines. 

Linked characterized valves. The relationship between angular rotation of the valve spindle and open area of the valve can be adjusted over different portions of the flow range using a series of screws. In this way, the air/gas ratio can be characterized to any desired profile over the whole firing range. These valves are suited to fully modulating systems and are commonly used on steam boilers. 

Gas boosters may be fitted with motor enclosures or designed to operate at lower rotating speeds. Alternatively, they may be housed in an acoustic enclosure within the boiler house. The booster and drive unit can be supplied with anti-vibration mountings to isolate it from the floor or steelwork and flexible bellows fitted to the gas inlet and outlet connections. 

The need to remove alkali material from the biogas stream depends on the end use for the gas. Problems associated with alkali vapor formation and deposition are critical in systems where the hot biogas is to be used without significant cool-down. Moderate gas cooling followed by removal of bulk particulates provides adequate cleaning for simple boiler systems that can tolerate some ash deposition. Other applications such as gas turbines require cleaner fuel gases. Since turbines operate at high rotational speeds, deposition can... 

Fuel oils are used extensively in War Plants, as, for example, a typical WWII TNT manufg plant used them iii sulfuric acid concentrators, in quadruple effect evaporators of TNT, red waste water, in rotating drums for incineration of the so-called "thick liquor" and as foel for heating boilers... 

Between the beaters or mills and the boilers, an apparatus for separating long fibre nitrocellulose from the cut fibres is inserted. This is a tank carrying a vertical cylindrical screen drum, with apertures 0.4 mm dia. The drum rotates and the cut fibres pass through the sieve into the drum, whence the contents flows to the boilers. The uncut fibres are caught on the surface of the screen from which they are removed by means of a brass knife and recycled to the beaters. 

In small-scale farm production of ethanol a possible environmental impact could occur through removal of crop residues for use as a boiler fuel. Crop residues are important because they help control soil erosion through their cover and provide nutrients, minerals, and fibrous material which help maintain soil quality. However, not more than one-third to one-half of the residues from a grain crop devoted to ethanol production need be used to fuel the process. Also, there are several methods, such as crop rotation and winter cover crops, which lessen the impact of crop residue removal. ... 

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